Q.1 What is the primary structural component of a liposome?
Proteins
Phospholipid bilayer
Carbohydrate polymer
Metallic core
Explanation - Liposomes are spherical vesicles formed by one or more phospholipid bilayers that encapsulate an aqueous core.
Correct answer is: Phospholipid bilayer
Q.2 Which technique is most commonly used to reduce the size of lipid vesicles to the nanoscale?
Extrusion
Lyophilization
Dialysis
Centrifugation
Explanation - Extrusion forces multilamellar vesicles through membranes with defined pore sizes, producing uniformly sized nanoliposomes.
Correct answer is: Extrusion
Q.3 In drug delivery, what advantage do liposomes offer over free drug molecules?
Increased electrical conductivity
Enhanced solubility and reduced toxicity
Higher magnetic susceptibility
Greater hardness
Explanation - Liposomes can encapsulate both hydrophilic and hydrophobic drugs, improving solubility and shielding the body from toxic effects.
Correct answer is: Enhanced solubility and reduced toxicity
Q.4 Which of the following is a common method for loading hydrophilic drugs into liposomes?
Reverse-phase evaporation
Solvent evaporation
Thin-film hydration
Layer-by-layer assembly
Explanation - Thin-film hydration forms a lipid film that, when hydrated, traps aqueous drug molecules inside the liposome core.
Correct answer is: Thin-film hydration
Q.5 What property of nanoparticles allows them to accumulate preferentially in tumor tissue?
Enhanced Permeability and Retention (EPR) effect
Magnetoresistance
Piezoelectricity
Thermal conductivity
Explanation - Tumor vasculature is leaky, allowing nanoparticles of certain sizes to passively accumulate, known as the EPR effect.
Correct answer is: Enhanced Permeability and Retention (EPR) effect
Q.6 Which material is NOT typically used to fabricate polymeric nanoparticles for drug delivery?
Polylactic acid (PLA)
Polyethylene glycol (PEG)
Silicon carbide
Polycaprolactone (PCL)
Explanation - Silicon carbide is a hard, inorganic material not commonly used for biodegradable polymeric nanoparticles.
Correct answer is: Silicon carbide
Q.7 What is the zeta potential of a particle primarily indicative of?
Particle size
Surface charge and stability
Magnetic susceptibility
Electrical resistance
Explanation - Zeta potential measures the electric potential at the slipping plane, influencing colloidal stability.
Correct answer is: Surface charge and stability
Q.8 Which of the following best describes a “stealth” liposome?
A liposome coated with antibodies
A liposome with a metallic shell
A liposome surface-modified with polyethylene glycol (PEG)
A liposome containing a magnetic core
Explanation - PEGylation reduces opsonization and prolongs circulation time, making liposomes 'stealthy'.
Correct answer is: A liposome surface-modified with polyethylene glycol (PEG)
Q.9 What is the typical size range for nanoliposomes used in intravenous drug delivery?
1–10 µm
100–300 nm
10–50 nm
500–1000 nm
Explanation - Nanoliposomes are generally designed within 100–300 nm to avoid rapid clearance and ensure tissue penetration.
Correct answer is: 100–300 nm
Q.10 In the context of nanomedicine, what does the term “targeting ligand” refer to?
A magnetic field used to guide nanoparticles
A chemical group that binds to specific cell receptors
A fluorescent tag for imaging
A polymer that stabilizes the nanoparticle
Explanation - Targeting ligands (e.g., antibodies, peptides) confer specificity by binding to receptors overexpressed on target cells.
Correct answer is: A chemical group that binds to specific cell receptors
Q.11 Which analytical technique is most suitable for determining the size distribution of liposomal formulations?
Nuclear magnetic resonance (NMR)
Dynamic light scattering (DLS)
Fourier transform infrared spectroscopy (FTIR)
Electrophoretic mobility shift assay
Explanation - DLS measures fluctuations in light scattering due to Brownian motion, providing size distribution data for nanoparticles.
Correct answer is: Dynamic light scattering (DLS)
Q.12 What is the main reason for incorporating cholesterol into liposome membranes?
To increase electrical conductivity
To improve membrane rigidity and reduce permeability
To make the liposome magnetic
To enable fluorescence imaging
Explanation - Cholesterol intercalates between phospholipids, stabilizing the bilayer and decreasing drug leakage.
Correct answer is: To improve membrane rigidity and reduce permeability
Q.13 Which of the following is a major limitation of using inorganic nanoparticles (e.g., gold) for drug delivery?
Low surface area
Rapid renal clearance
Potential long-term toxicity
Inability to be functionalized
Explanation - Inorganic particles may accumulate in organs and cause toxicity; biodegradability is a concern.
Correct answer is: Potential long-term toxicity
Q.14 What does the term “burst release” describe in nanoparticle drug delivery?
A sudden rapid release of drug shortly after administration
Continuous slow release over weeks
Release triggered by magnetic fields
Release only after cellular uptake
Explanation - Burst release can lead to high initial drug concentrations, often undesired for controlled delivery.
Correct answer is: A sudden rapid release of drug shortly after administration
Q.15 Which method is commonly employed to produce polymeric nanoparticles via a bottom‑up approach?
Milling
Emulsion solvent evaporation
Laser ablation
Electrospinning
Explanation - In this method, a polymer solution is emulsified in water, and solvent evaporation yields solid nanoparticles.
Correct answer is: Emulsion solvent evaporation
Q.16 In a liposomal formulation, what is the purpose of using a pH‑sensitive lipid?
To enhance magnetic resonance imaging
To trigger drug release in acidic tumor microenvironments
To increase electrical conductivity
To improve thermal stability
Explanation - pH‑sensitive lipids destabilize under acidic conditions, releasing encapsulated drugs preferentially at tumor sites.
Correct answer is: To trigger drug release in acidic tumor microenvironments
Q.17 Which of the following best defines the term “bio‑nanocomposite” in drug delivery?
A composite of biological molecules and inorganic nanoparticles
A mixture of polymers and metal powders
A blend of sugars and fats
A combination of gases and liquids
Explanation - Bio‑nanocomposites integrate biomolecules (e.g., proteins) with nanomaterials to achieve synergistic therapeutic functions.
Correct answer is: A composite of biological molecules and inorganic nanoparticles
Q.18 Which parameter is most directly related to the ability of a nanoparticle to cross the blood‑brain barrier (BBB)?
Particle size below 100 nm
High zeta potential (> +40 mV)
Presence of a metallic core
Large surface roughness
Explanation - Nanoparticles smaller than ~100 nm can more readily traverse the tight junctions of the BBB, especially when surface-modified.
Correct answer is: Particle size below 100 nm
Q.19 Which of the following is a typical method for functionalizing the surface of polymeric nanoparticles with targeting ligands?
Physical adsorption
Covalent coupling via carbodiimide chemistry
Thermal annealing
Magnetron sputtering
Explanation - Carbodiimide reagents (e.g., EDC/NHS) enable stable amide bond formation between carboxyl groups on the polymer and amine groups on ligands.
Correct answer is: Covalent coupling via carbodiimide chemistry
Q.20 What is the main advantage of using dendrimers over conventional polymeric nanoparticles for drug delivery?
Higher electrical conductivity
Precisely defined size and multivalent surface functionality
Magnetic responsiveness
Lower production cost
Explanation - Dendrimers have a branched architecture with monodisperse size and many terminal groups for drug conjugation.
Correct answer is: Precisely defined size and multivalent surface functionality
Q.21 Which of the following is NOT a common trigger for stimulus‑responsive drug release from nanocarriers?
pH change
Ultrasound
Gravitational waves
Redox potential
Explanation - pH, ultrasound, temperature, and redox conditions are typical stimuli; gravitational waves are not used in biomedical contexts.
Correct answer is: Gravitational waves
Q.22 In the context of liposome stability, what does the term "leakage" refer to?
Escape of encapsulated drug into the surrounding medium
Loss of phospholipid molecules from the bilayer
Change in electrical conductivity of the suspension
Increase in particle size due to aggregation
Explanation - Leakage denotes undesired diffusion of drug from the liposome interior, reducing therapeutic efficacy.
Correct answer is: Escape of encapsulated drug into the surrounding medium
Q.23 Which imaging modality can directly visualize the biodistribution of gold nanoparticles?
Computed tomography (CT)
Magnetic resonance imaging (MRI)
Positron emission tomography (PET)
Ultrasound
Explanation - Gold's high atomic number provides strong X‑ray attenuation, enhancing contrast in CT scans.
Correct answer is: Computed tomography (CT)
Q.24 What is the purpose of “freeze‑drying” (lyophilization) liposomal formulations?
To increase electrical conductivity
To improve long‑term stability and shelf life
To reduce particle size
To embed magnetic nanoparticles
Explanation - Lyophilization removes water, preventing hydrolysis and aggregation, thus extending product stability.
Correct answer is: To improve long‑term stability and shelf life
Q.25 Which of the following polymeric nanoparticles is known for its pH‑sensitive swelling behavior?
Polystyrene
Poly(N‑isopropylacrylamide) (PNIPAM)
Poly(lactic‑co‑glycolic acid) (PLGA)
Poly(ethylene glycol) (PEG)
Explanation - PNIPAM exhibits a lower critical solution temperature and can swell or collapse in response to pH and temperature changes.
Correct answer is: Poly(N‑isopropylacrylamide) (PNIPAM)
Q.26 When a drug-loaded liposome is administered intravenously, which organ’s reticuloendothelial system (RES) primarily clears it?
Kidney
Heart
Liver and spleen
Brain
Explanation - Macrophages in the liver (Kupffer cells) and spleen recognize and phagocytose foreign particles, including liposomes.
Correct answer is: Liver and spleen
Q.27 Which property of a nanoparticle determines its ability to generate a localized hyperthermia effect under an alternating magnetic field?
Magnetic susceptibility
Electrical resistance
Optical reflectivity
Acoustic impedance
Explanation - Superparamagnetic nanoparticles convert magnetic energy into heat when exposed to an alternating magnetic field.
Correct answer is: Magnetic susceptibility
Q.28 What is the typical purpose of adding a surfactant like Tween‑80 during nanoparticle synthesis?
To increase particle density
To prevent aggregation and stabilize the colloidal suspension
To enhance magnetic properties
To induce fluorescence
Explanation - Surfactants lower interfacial tension and provide steric or electrostatic stabilization of nanoparticles.
Correct answer is: To prevent aggregation and stabilize the colloidal suspension
Q.29 Which of the following best explains why PEGylated nanoparticles have prolonged circulation time?
PEG increases particle size beyond renal clearance threshold
PEG creates a hydrophilic shell that reduces protein adsorption
PEG makes particles magnetic
PEG provides a positive surface charge
Explanation - The hydrated PEG layer sterically hinders opsonins from binding, decreasing clearance by the RES.
Correct answer is: PEG creates a hydrophilic shell that reduces protein adsorption
Q.30 Which of the following is a common biodegradable polymer used for making nanoparticles for controlled drug release?
Polyvinyl chloride (PVC)
Polylactic acid (PLA)
Polyethylene terephthalate (PET)
Polytetrafluoroethylene (PTFE)
Explanation - PLA hydrolyzes into lactic acid, making it suitable for biodegradable drug delivery systems.
Correct answer is: Polylactic acid (PLA)
Q.31 What does the term “critical micelle concentration (CMC)” refer to in the context of amphiphilic block copolymers?
The minimum concentration needed for micelle formation
The concentration at which particles become magnetic
The point where polymer degrades
The concentration required for fluorescence
Explanation - CMC is the concentration above which amphiphilic molecules self‑assemble into micelles in solution.
Correct answer is: The minimum concentration needed for micelle formation
Q.32 Which of the following is an advantage of using microfluidic devices for liposome production?
Higher electrical conductivity
Precise control over size and polydispersity
Ability to embed metallic cores
Reduced need for surfactants
Explanation - Microfluidics provides laminar flow conditions that enable reproducible liposome size tuning.
Correct answer is: Precise control over size and polydispersity
Q.33 In nanocarrier design, what is meant by “active targeting”?
Using external magnetic fields to guide particles
Functionalizing carriers with ligands that bind to specific cellular receptors
Increasing particle size to improve retention
Relying on passive diffusion across membranes
Explanation - Active targeting uses specific biomolecular interactions to enhance uptake by target cells.
Correct answer is: Functionalizing carriers with ligands that bind to specific cellular receptors
Q.34 Which analytical method would you use to quantify the amount of drug encapsulated within liposomes?
High‑performance liquid chromatography (HPLC)
Scanning electron microscopy (SEM)
X‑ray diffraction (XRD)
Thermogravimetric analysis (TGA)
Explanation - HPLC separates and quantifies the drug after lysing the liposomes, providing encapsulation efficiency data.
Correct answer is: High‑performance liquid chromatography (HPLC)
Q.35 What is the primary reason for using a “double‑emulsion” (W/O/W) technique in nanoparticle fabrication?
To create magnetic nanoparticles
To encapsulate hydrophilic drugs within polymeric particles
To increase particle conductivity
To produce metallic nanorods
Explanation - The double‑emulsion method traps aqueous drug solution inside a polymeric shell, suitable for water‑soluble agents.
Correct answer is: To encapsulate hydrophilic drugs within polymeric particles
Q.36 Which of the following best characterizes the term “nanotoxicology”?
Study of electrical properties of nanomaterials
Investigation of adverse biological effects of nanomaterials
Analysis of nanomaterial cost effectiveness
Design of nanomaterial synthesis pathways
Explanation - Nanotoxicology focuses on understanding how nanoscale materials interact with biological systems, potentially causing toxicity.
Correct answer is: Investigation of adverse biological effects of nanomaterials
Q.37 Which physicochemical characteristic of a nanoparticle most influences its renal clearance?
Surface charge
Particle size below ~5 nm
Magnetic susceptibility
Shape anisotropy
Explanation - Very small particles can be filtered by the glomerulus and excreted in urine.
Correct answer is: Particle size below ~5 nm
Q.38 What does the term “hydrophobic drug loading” refer to in liposome preparation?
Incorporation of drug into the aqueous core
Integration of drug into the lipid bilayer
Attachment of drug to surface PEG chains
Encapsulation within a polymeric shell
Explanation - Hydrophobic drugs partition into the non‑polar region of the lipid bilayer during liposome formation.
Correct answer is: Integration of drug into the lipid bilayer
Q.39 Which of the following is a common biodegradable metal used in nano‑carriers for bone regeneration?
Magnesium
Gold
Copper
Silver
Explanation - Magnesium degrades in physiological conditions and can support bone tissue engineering applications.
Correct answer is: Magnesium
Q.40 In a nanoparticle‑based vaccine, what is the main benefit of presenting antigen on the particle surface?
Increases antigen solubility
Improves antigen uptake by antigen‑presenting cells
Reduces antigen stability
Makes the vaccine magnetic
Explanation - Surface‑displayed antigens are more readily recognized and processed by dendritic cells, enhancing immune response.
Correct answer is: Improves antigen uptake by antigen‑presenting cells
Q.41 Which parameter is most critical for ensuring that a nanoparticle can be aerosolized for pulmonary delivery?
Zeta potential > +30 mV
Particle aerodynamic diameter between 1–5 µm
Magnetic susceptibility
Electrical conductivity
Explanation - Particles in this size range deposit efficiently in the deep lungs without being exhaled or trapped in the upper airway.
Correct answer is: Particle aerodynamic diameter between 1–5 µm
Q.42 Which of the following best describes “layer‑by‑layer (LbL) assembly” for nanoparticle coating?
Sequential adsorption of oppositely charged polyelectrolytes
Embedding particles in a metallic matrix
Sintering nanoparticles at high temperature
Coating particles with a single polymer film
Explanation - LbL builds multilayer shells by alternately depositing positively and negatively charged polymers, enabling precise control of thickness and functionality.
Correct answer is: Sequential adsorption of oppositely charged polyelectrolytes
Q.43 What is the main reason to incorporate a fluorescent dye into liposomes for research purposes?
To increase drug loading capacity
To track liposome biodistribution using imaging
To make liposomes magnetic
To enhance liposome stability
Explanation - Fluorescent labels allow visualization of liposome location in vitro and in vivo via fluorescence microscopy or imaging systems.
Correct answer is: To track liposome biodistribution using imaging
Q.44 Which of the following mechanisms describes how a pH‑responsive polymeric nanoparticle releases its payload in acidic tumor tissue?
Polymer swelling due to protonation
Magnetic heating
Electrostatic repulsion from negative charges
Thermal degradation
Explanation - Acidic pH protonates ionizable groups, causing the polymer matrix to swell or dissolve and release the drug.
Correct answer is: Polymer swelling due to protonation
Q.45 Which analytical technique can directly measure the surface chemical composition of nanoparticles?
X‑ray photoelectron spectroscopy (XPS)
Atomic force microscopy (AFM)
Dynamic light scattering (DLS)
Differential scanning calorimetry (DSC)
Explanation - XPS detects elemental composition and chemical states within the top few nanometers of a material’s surface.
Correct answer is: X‑ray photoelectron spectroscopy (XPS)
Q.46 In the context of drug delivery, what is meant by the term “pharmacokinetics”?
The study of drug-receptor binding affinities
The absorption, distribution, metabolism, and excretion of a drug
The electrical conductivity of a drug solution
The magnetic properties of a drug carrier
Explanation - Pharmacokinetics describes how the body handles a drug over time, critical for evaluating delivery systems.
Correct answer is: The absorption, distribution, metabolism, and excretion of a drug
Q.47 Which of the following is a common trigger for thermally responsive drug release from liposomes?
Application of focused ultrasound
Exposure to UV light
Magnetic field modulation
pH change
Explanation - Focused ultrasound can locally raise temperature, causing phase transition in temperature‑sensitive lipids and releasing the drug.
Correct answer is: Application of focused ultrasound
Q.48 What does the term “hydrodynamic diameter” refer to when measuring nanoparticles?
The actual crystal lattice size
The effective diameter of a particle moving through a fluid, including its solvation layer
The diameter of the particle’s metallic core
The diameter measured by electron microscopy
Explanation - Hydrodynamic diameter accounts for the particle plus any bound solvent molecules, as measured by DLS.
Correct answer is: The effective diameter of a particle moving through a fluid, including its solvation layer
Q.49 Which of the following best explains why “negative surface charge” can improve nanoparticle circulation time?
Negatively charged particles repel blood cells, preventing aggregation
Negatively charged surfaces attract opsonins, enhancing clearance
Negative charge leads to rapid renal excretion
Negative charge improves magnetic properties
Explanation - A modest negative charge reduces protein adsorption and aggregation, helping nanoparticles evade rapid clearance.
Correct answer is: Negatively charged particles repel blood cells, preventing aggregation
Q.50 Which method is most suitable for preparing solid lipid nanoparticles (SLNs)?
High‑shear homogenization followed by cooling
Solvent evaporation in an oil‑in‑water emulsion
Electrospinning
Spray‑drying
Explanation - The method melts lipids, emulsifies them under high shear, and then solidifies the particles upon cooling.
Correct answer is: High‑shear homogenization followed by cooling
Q.51 What is the main purpose of using a “targeting peptide” such as RGD on a nanoparticle surface?
To increase particle size
To bind integrin receptors on tumor endothelial cells
To provide fluorescent signal
To make the particle magnetic
Explanation - RGD peptide specifically recognizes integrins, facilitating selective accumulation in angiogenic tissues.
Correct answer is: To bind integrin receptors on tumor endothelial cells
Q.52 Which of the following is a key advantage of using microbubbles in combination with liposomal drug carriers for ultrasound‑mediated delivery?
Microbubbles increase electrical conductivity of the formulation
They provide a scaffold for magnetic targeting
Cavitation of microbubbles enhances liposome permeability and drug release
Microbubbles act as a fluorescent marker
Explanation - Ultrasound‑induced microbubble cavitation creates mechanical forces that transiently disrupt liposome membranes, facilitating drug release.
Correct answer is: Cavitation of microbubbles enhances liposome permeability and drug release
Q.53 In the context of nanocarriers, what does the term “bioavailability” refer to?
The proportion of the administered dose that reaches systemic circulation in an active form
The electrical resistance of the carrier
The magnetic susceptibility of the nanoparticle
The optical density of the formulation
Explanation - Bioavailability measures how much of the drug becomes available at the target site after delivery.
Correct answer is: The proportion of the administered dose that reaches systemic circulation in an active form
Q.54 Which nanocarrier type is most appropriate for delivering siRNA molecules?
Hydrophobic polymeric nanoparticles
Cationic liposomes or lipid‑polymer hybrids
Metallic nanorods
Silica nanospheres
Explanation - Cationic carriers can complex with negatively charged siRNA, protecting it from degradation and facilitating cellular uptake.
Correct answer is: Cationic liposomes or lipid‑polymer hybrids
Q.55 Which of the following is a common method for measuring drug release kinetics from liposomes in vitro?
Dialysis bag method
Scanning electron microscopy
X‑ray diffraction
Thermal gravimetric analysis
Explanation - Liposomes are placed inside a dialysis membrane, and drug diffusion into the external medium is monitored over time.
Correct answer is: Dialysis bag method
Q.56 What is the main reason that “nanoparticle shape” (e.g., rod vs. sphere) influences cellular uptake?
Shape determines magnetic properties
Different shapes interact with cell membranes in distinct ways, affecting endocytosis pathways
Shape changes the electrical conductivity of the particle
Shape controls the drug’s chemical stability
Explanation - Cellular membranes recognize curvature and aspect ratio, influencing the efficiency and route of internalization.
Correct answer is: Different shapes interact with cell membranes in distinct ways, affecting endocytosis pathways
Q.57 Which of the following polymers is widely used to create “stealth” nanoparticles due to its hydrophilic nature?
Poly(lactic‑co‑glycolic acid) (PLGA)
Poly(ethylene glycol) (PEG)
Polystyrene (PS)
Polyvinyl alcohol (PVA)
Explanation - PEG creates a hydration layer that reduces protein adsorption and opsonization.
Correct answer is: Poly(ethylene glycol) (PEG)
Q.58 Which factor primarily determines the “release profile” of a drug from polymeric nanoparticles?
Polymer degradation rate
Magnetic field strength
Particle color
Electrical voltage applied
Explanation - As the polymer matrix degrades, drug molecules are liberated, dictating the kinetics of release.
Correct answer is: Polymer degradation rate
Q.59 What is the purpose of using a “cryoprotectant” such as trehalose during lyophilization of liposomes?
To increase particle charge
To protect liposomes from damage during freezing and drying
To make the formulation magnetic
To reduce surface tension
Explanation - Cryoprotectants prevent ice crystal formation that can disrupt lipid bilayers during freeze‑drying.
Correct answer is: To protect liposomes from damage during freezing and drying
Q.60 Which type of liposome contains multiple concentric lipid bilayers?
Multilamellar vesicle (MLV)
Small unilamellar vesicle (SUV)
Large unilamellar vesicle (LUV)
Stealth liposome
Explanation - MLVs have several lipid bilayer shells resembling an onion structure.
Correct answer is: Multilamellar vesicle (MLV)
Q.61 In a nanoparticle formulation, why might a researcher choose to use a “click chemistry” reaction for surface functionalization?
It requires high temperatures
It provides a rapid, specific, and bio‑orthogonal coupling method
It makes the particles conductive
It reduces particle size
Explanation - Click reactions (e.g., azide‑alkyne cycloaddition) proceed efficiently under mild conditions without interfering with biomolecules.
Correct answer is: It provides a rapid, specific, and bio‑orthogonal coupling method
Q.62 Which of the following is NOT a typical advantage of using nanocarriers for ocular drug delivery?
Enhanced penetration through corneal barriers
Reduced dosing frequency
Improved drug solubility
Increased systemic absorption
Explanation - Nanocarriers aim to localize drug effect in the eye while minimizing systemic exposure.
Correct answer is: Increased systemic absorption
Q.63 What is the main function of a “prodrug” strategy when combined with nanoparticle delivery?
To increase particle conductivity
To temporarily mask drug activity until activation at the target site
To make the nanoparticle magnetic
To change the particle’s shape
Explanation - Prodrugs are inactive precursors that are converted to the active drug by enzymes or conditions present at the target.
Correct answer is: To temporarily mask drug activity until activation at the target site
Q.64 Which of the following nanocarriers is best suited for delivering a large protein therapeutic?
Liposomes with a thin bilayer
Solid lipid nanoparticles
Polymeric nanoparticles made from PLGA
Gold nanorods
Explanation - PLGA nanoparticles can encapsulate proteins in a protective matrix, maintaining activity and providing controlled release.
Correct answer is: Polymeric nanoparticles made from PLGA
Q.65 What does the term “endosomal escape” refer to in intracellular drug delivery?
The process by which a nanoparticle leaves the cell nucleus
The ability of a carrier to exit the endosome into the cytosol before degradation
The dissolution of the carrier in blood plasma
The migration of the carrier across the cell membrane
Explanation - Effective delivery of nucleic acids often requires escaping the endosomal pathway to avoid lysosomal degradation.
Correct answer is: The ability of a carrier to exit the endosome into the cytosol before degradation
Q.66 Which technique can be used to impart magnetic responsiveness to polymeric nanoparticles?
Incorporating iron oxide (Fe₃O₄) nanoparticles during synthesis
Coating with gold shell
Adding fluorescent dyes
Embedding silicon nanowires
Explanation - Iron oxide provides superparamagnetic behavior, enabling magnetic guidance or hyperthermia applications.
Correct answer is: Incorporating iron oxide (Fe₃O₄) nanoparticles during synthesis
Q.67 Which of the following best explains why “size uniformity” (low polydispersity index) is important for nanocarrier performance?
Uniform size improves optical transparency
Consistent size leads to predictable pharmacokinetics and biodistribution
Uniform particles have higher magnetic susceptibility
It reduces the need for surfactants
Explanation - Low polydispersity ensures that the majority of particles behave similarly in vivo, enhancing reproducibility.
Correct answer is: Consistent size leads to predictable pharmacokinetics and biodistribution
Q.68 Which of the following is a key factor influencing the “critical packing parameter” (CPP) that determines liposome morphology?
Headgroup size, tail volume, and tail length of phospholipids
Electrical conductivity of the solution
Magnetic field strength during formation
Temperature of the lyophilization process
Explanation - CPP = v / (a₀ × l) where v = tail volume, a₀ = headgroup area, l = tail length; it predicts whether lipids form micelles, bilayers, or inverted phases.
Correct answer is: Headgroup size, tail volume, and tail length of phospholipids
Q.69 What is the primary role of a “co-surfactant” in the preparation of nanoemulsions for drug delivery?
To increase the viscosity of the formulation
To further reduce interfacial tension and stabilize the emulsion droplets
To impart magnetic properties
To provide fluorescence
Explanation - Co‑surfactants work synergistically with primary surfactants to achieve smaller, more stable droplets.
Correct answer is: To further reduce interfacial tension and stabilize the emulsion droplets
Q.70 Which of the following best describes a “nanogel”?
A rigid inorganic nanoparticle
A cross‑linked polymer network that swells in water
A metallic nanowire
A lipid vesicle with multiple layers
Explanation - Nanogels are soft, hydrated particles capable of loading and releasing drugs in response to stimuli.
Correct answer is: A cross‑linked polymer network that swells in water
Q.71 In drug delivery research, what does the abbreviation “IC₅₀” represent?
The concentration of drug that inhibits 50 % of a target activity
The temperature at which 50 % of liposomes melt
The particle size at which 50 % of nanoparticles aggregate
The pH at which 50 % of the drug is ionized
Explanation - IC₅₀ is a standard metric for drug potency, indicating the dose required for half-maximal inhibition.
Correct answer is: The concentration of drug that inhibits 50 % of a target activity
Q.72 Which of the following is a common method to assess the cytotoxicity of a new nanoparticle formulation?
MTT assay
X‑ray diffraction
Fourier transform infrared spectroscopy
Dynamic light scattering
Explanation - The MTT assay measures cell metabolic activity as an indicator of viability after exposure to the formulation.
Correct answer is: MTT assay
Q.73 What effect does increasing the cholesterol content in a liposome typically have on its permeability?
Increases permeability to all solutes
Decreases membrane permeability, reducing drug leakage
Makes the membrane electrically conductive
Changes the liposome shape from spherical to rod‑like
Explanation - Cholesterol packs between phospholipids, tightening the bilayer and limiting passive diffusion of encapsulated compounds.
Correct answer is: Decreases membrane permeability, reducing drug leakage
Q.74 Which of the following is a key advantage of using “microfluidic jetting” for liposome production?
Ability to generate liposomes with a metallic core
Precise control over size and rapid, continuous production
Production of highly charged liposomes
Direct incorporation of DNA without additional steps
Explanation - Microfluidic jetting enables fine-tuning of flow rates and mixing, yielding uniform liposomes at scale.
Correct answer is: Precise control over size and rapid, continuous production
Q.75 What is the primary reason for using a “pH‑gradient” loading method for weakly basic drugs into liposomes?
To increase particle size
To drive drug accumulation into the acidic interior via ion trapping
To make liposomes magnetic
To change the surface charge to positive
Explanation - A transmembrane pH gradient causes weak bases to become protonated inside the liposome, trapping them and achieving high encapsulation efficiency.
Correct answer is: To drive drug accumulation into the acidic interior via ion trapping
Q.76 Which type of nanoparticle is most suitable for simultaneous imaging and therapy (theranostics)?
Gold nanoshells
Silica nanospheres
Polystyrene beads
Alginate microspheres
Explanation - Gold nanoshells possess strong optical absorption for imaging and can convert light to heat for photothermal therapy.
Correct answer is: Gold nanoshells
Q.77 Which of the following parameters is directly measured by a “zeta potential analyzer”?
Particle size distribution
Surface charge potential
Magnetic susceptibility
Thermal conductivity
Explanation - Zeta potential analyzers calculate the electrokinetic potential, indicating colloidal stability.
Correct answer is: Surface charge potential
Q.78 What is the main benefit of using “polymeric micelles” for delivering poorly water‑soluble drugs?
They increase the drug’s magnetic properties
They solubilize hydrophobic drugs within the core, improving bioavailability
They make the drug fluorescent
They reduce the drug’s molecular weight
Explanation - The hydrophobic core of polymeric micelles can encapsulate insoluble drugs, enhancing dissolution in aqueous environments.
Correct answer is: They solubilize hydrophobic drugs within the core, improving bioavailability
Q.79 Which of the following is a typical reason to use “ionic gelation” for forming chitosan nanoparticles?
To create magnetic particles
To crosslink chitosan with multivalent anions, forming stable nanoparticles at mild conditions
To increase particle electrical conductivity
To embed gold nanorods
Explanation - Ionic gelation uses agents like tripolyphosphate (TPP) to crosslink positively charged chitosan, creating nanoparticles without harsh chemicals.
Correct answer is: To crosslink chitosan with multivalent anions, forming stable nanoparticles at mild conditions
Q.80 Which of the following best defines the “enhanced permeability and retention (EPR) effect”?
Increased electrical conductivity of tumor tissue
Passive accumulation of macromolecules and nanoparticles in tumor tissue due to leaky vasculature and poor lymphatic drainage
Active transport of drugs across the blood‑brain barrier
Magnetic attraction of nanoparticles to tumors
Explanation - The EPR effect is a cornerstone of passive tumor targeting for nanomedicines.
Correct answer is: Passive accumulation of macromolecules and nanoparticles in tumor tissue due to leaky vasculature and poor lymphatic drainage
Q.81 What is the purpose of a “burst release” suppressor such as a polymeric coating on a nanoparticle?
To increase magnetic responsiveness
To prevent rapid initial drug leakage and achieve more controlled release
To make the particle fluorescent
To enlarge the particle size beyond 1 µm
Explanation - A coating can act as a diffusion barrier, reducing the early spike in drug concentration.
Correct answer is: To prevent rapid initial drug leakage and achieve more controlled release
Q.82 Which method is most suitable for preparing lipid‑polymer hybrid nanoparticles (LPHNs)?
Single‑step nanoprecipitation followed by lipid film hydration
Electrospinning
Sputter coating
High‑temperature sintering
Explanation - Nanoprecipitation creates the polymer core, then a lipid layer is added, yielding hybrid structures.
Correct answer is: Single‑step nanoprecipitation followed by lipid film hydration
Q.83 Which of the following statements about “active targeting” versus “passive targeting” is correct?
Passive targeting requires ligands on the particle surface, while active does not
Active targeting relies on specific ligand‑receptor interactions; passive relies on physicochemical properties like size
Passive targeting provides higher specificity than active targeting
Active targeting only works for oral drug delivery
Explanation - Active targeting uses molecular recognition; passive targeting exploits size, charge, and the EPR effect.
Correct answer is: Active targeting relies on specific ligand‑receptor interactions; passive relies on physicochemical properties like size
Q.84 Which of the following is an advantage of using “polymeric dendrimers” over traditional polymeric nanoparticles for drug delivery?
Higher mechanical strength
Monodisperse size and a high density of surface functional groups
Intrinsic magnetic properties
Increased opacity
Explanation - Dendrimers have a well‑defined architecture with many terminal groups for drug attachment or targeting.
Correct answer is: Monodisperse size and a high density of surface functional groups
Q.85 What is the main purpose of using a “cryogenic electron microscopy (cryo‑EM)” technique in liposome research?
To measure electrical conductivity
To visualize the native hydrated structure of liposomes at high resolution
To determine magnetic susceptibility
To assess drug release rate
Explanation - Cryo‑EM preserves liposomes in vitreous ice, allowing direct observation of size, lamellarity, and morphology.
Correct answer is: To visualize the native hydrated structure of liposomes at high resolution
Q.86 Which of the following best explains why “PEGylated liposomes” have reduced uptake by Kupffer cells?
PEG creates a steric barrier that hinders protein adsorption and recognition by phagocytes
PEG makes the liposome magnetic
PEG increases the surface charge to highly positive values
PEG reduces the particle size below 10 nm
Explanation - The hydrated PEG chain masks the liposome surface, decreasing opsonization and subsequent clearance by liver macrophages.
Correct answer is: PEG creates a steric barrier that hinders protein adsorption and recognition by phagocytes
Q.87 Which of the following is a typical method to assess the encapsulation efficiency (EE) of a drug in liposomes?
Centrifugation to separate free drug, followed by quantitative analysis of the pellet
Measuring zeta potential
Scanning electron microscopy
Thermal gravimetric analysis
Explanation - After separating unencapsulated drug, the amount of drug retained in the liposome pellet is quantified to calculate EE.
Correct answer is: Centrifugation to separate free drug, followed by quantitative analysis of the pellet
Q.88 In nanomedicine, what does the term “theranostics” refer to?
A device that measures temperature and conductivity
Combined therapy and diagnostics within a single nanocarrier
A magnetic resonance imaging technique
A type of electrophoresis
Explanation - Theranostic agents deliver a therapeutic payload while providing imaging capabilities to monitor treatment.
Correct answer is: Combined therapy and diagnostics within a single nanocarrier
Q.89 Which of the following is the most appropriate technique for determining the drug release profile of a temperature‑sensitive liposome?
Differential scanning calorimetry (DSC)
Dynamic light scattering (DLS)
Dialysis method with temperature‑controlled bath
Fourier transform infrared spectroscopy (FTIR)
Explanation - Placing liposomes in a dialysis setup at varying temperatures allows measurement of drug diffusion rates in response to temperature changes.
Correct answer is: Dialysis method with temperature‑controlled bath
Q.90 Which polymer is commonly used to form “nanocapsules” with a core‑shell architecture for drug encapsulation?
Polylactic acid (PLA)
Polyvinyl chloride (PVC)
Polyethylene terephthalate (PET)
Polystyrene (PS)
Explanation - PLA can be processed to form a solid polymeric shell around a liquid or solid core, creating nanocapsules for controlled release.
Correct answer is: Polylactic acid (PLA)
Q.91 What is the main function of a “pH‑responsive polymer” such as poly(L‑histidine) in a nanocarrier?
To increase particle conductivity
To swell or disassemble under acidic conditions, triggering drug release
To make the carrier magnetic
To generate fluorescence
Explanation - Poly(L‑histidine) becomes protonated in acidic environments, causing structural changes that release the encapsulated drug.
Correct answer is: To swell or disassemble under acidic conditions, triggering drug release
Q.92 Which of the following is a typical indicator that a liposome formulation has high stability during storage?
Constant particle size and low polydispersity index over time
Increasing zeta potential over weeks
Rapid color change of the suspension
Visible precipitation within 24 hours
Explanation - Stable formulations maintain size distribution and do not aggregate or degrade during storage.
Correct answer is: Constant particle size and low polydispersity index over time
Q.93 Which of the following best explains why “nanoparticles” can cross cellular membranes more efficiently than larger particles?
Nanoparticles have higher magnetic susceptibility
Their small size enables uptake via endocytosis and even passive diffusion in some cases
They generate heat that opens pores
They alter the cell’s DNA
Explanation - Cellular uptake mechanisms such as clathrin‑mediated endocytosis preferentially internalize nanoscale objects.
Correct answer is: Their small size enables uptake via endocytosis and even passive diffusion in some cases
Q.94 What is the main reason for using a “double‑layered” liposome (also called a “multilamellar vesicle”) for vaccine delivery?
To increase electrical conductivity
To provide higher antigen payload and sustained release
To make the formulation magnetic
To reduce the need for refrigeration
Explanation - Multilamellar vesicles have multiple bilayers, allowing more antigen to be incorporated and extending release over time.
Correct answer is: To provide higher antigen payload and sustained release
Q.95 Which analytical technique would you use to verify the chemical identity of a polymer used in nanoparticle synthesis?
Nuclear magnetic resonance (NMR) spectroscopy
Dynamic light scattering (DLS)
Scanning electron microscopy (SEM)
Zeta potential measurement
Explanation - NMR provides detailed information about molecular structure and composition of polymers.
Correct answer is: Nuclear magnetic resonance (NMR) spectroscopy
Q.96 Which of the following best describes the “critical micelle concentration (CMC)” for amphiphilic block copolymers?
The temperature at which micelles melt
The concentration above which micelles spontaneously form in solution
The magnetic field strength needed to align micelles
The pressure required to compress micelles
Explanation - CMC is a key parameter dictating the stability of micellar drug carriers in aqueous media.
Correct answer is: The concentration above which micelles spontaneously form in solution
Q.97 Why are “superparamagnetic iron oxide nanoparticles (SPIONs)” frequently used in magnetic resonance imaging (MRI) contrast agents?
They emit fluorescence
They alter local magnetic fields, enhancing T2 contrast without retaining magnetization after field removal
They increase the electrical conductivity of tissues
They produce heat at room temperature
Explanation - Superparamagnetic behavior provides strong T2 shortening while avoiding residual magnetization that could cause artifacts.
Correct answer is: They alter local magnetic fields, enhancing T2 contrast without retaining magnetization after field removal
Q.98 Which of the following is a potential drawback of using high amounts of surfactant in nanoparticle formulations?
Improved drug loading
Increased cytotoxicity and possible irritation
Enhanced magnetic properties
Reduced particle size
Explanation - Excess surfactant can be toxic to cells and may cause adverse reactions in vivo.
Correct answer is: Increased cytotoxicity and possible irritation
Q.99 In the context of drug delivery, what does the term “first‑pass metabolism” refer to?
The metabolism of a drug after it reaches the target tissue
The metabolism of a drug in the liver immediately after oral administration before it reaches systemic circulation
The degradation of a nanoparticle in the bloodstream
The oxidation of a drug by lung tissue
Explanation - First‑pass metabolism reduces bioavailability of orally administered drugs, which nanocarriers can help bypass.
Correct answer is: The metabolism of a drug in the liver immediately after oral administration before it reaches systemic circulation
Q.100 Which of the following best explains the concept of “controlled release” in nanoparticle drug delivery?
Instantaneous release of the entire drug dose
Release of the drug at a predetermined rate over a set period
Release only when the particle is heated to 200 °C
Release triggered by exposure to ultraviolet light only
Explanation - Controlled release aims to maintain therapeutic drug levels while minimizing peaks and troughs.
Correct answer is: Release of the drug at a predetermined rate over a set period
Q.101 Which type of lipid is most commonly used to create “cationic liposomes” for nucleic acid delivery?
Dioleoylphosphatidylcholine (DOPC)
1,2‑Dioleoyl‑3‑trimethylammonium‑propane (DOTAP)
Sphingomyelin
Cholesterol
Explanation - DOTAP carries a permanent positive charge, enabling electrostatic complexation with negatively charged nucleic acids.
Correct answer is: 1,2‑Dioleoyl‑3‑trimethylammonium‑propane (DOTAP)
Q.102 Which of the following is a common reason to use “high‑pressure homogenization” in nanoparticle production?
To increase the magnetic susceptibility of particles
To reduce particle size and achieve narrow size distribution
To embed fluorescent dyes into the core
To raise the temperature of the formulation
Explanation - High‑pressure homogenization forces the suspension through a narrow valve at high pressure, breaking particles into nanoscale fragments.
Correct answer is: To reduce particle size and achieve narrow size distribution
Q.103 What is the primary purpose of using a “targeting antibody” on the surface of a nanoparticle?
To increase particle density
To specifically bind to antigens overexpressed on diseased cells
To change the particle’s color
To make the particle magnetic
Explanation - Antibodies provide high specificity, directing the nanocarrier to cells expressing the target antigen.
Correct answer is: To specifically bind to antigens overexpressed on diseased cells
Q.104 Which of the following best describes the role of “osmotic pressure” in the stability of liposomes?
High osmotic pressure inside liposomes causes them to burst and release cargo
Balanced osmotic pressure between interior and exterior prevents swelling or shrinkage
Osmotic pressure determines magnetic responsiveness
Osmotic pressure controls surface charge
Explanation - Equalizing osmotic conditions avoids liposome deformation and leakage.
Correct answer is: Balanced osmotic pressure between interior and exterior prevents swelling or shrinkage
Q.105 Which of the following statements about “nanoparticle aggregation” is TRUE?
Aggregation always improves drug delivery efficacy
Aggregation can increase particle size, leading to rapid clearance and reduced bioavailability
Aggregation makes particles more fluorescent
Aggregation reduces zeta potential to zero
Explanation - Aggregated particles may be recognized and cleared by the RES, and may not reach target sites effectively.
Correct answer is: Aggregation can increase particle size, leading to rapid clearance and reduced bioavailability
Q.106 Which of the following is a common method to achieve “pH‑triggered drug release” from polymeric nanoparticles?
Incorporating acid‑labile linkers that cleave under acidic conditions
Embedding metallic cores
Using magnetic fields
Adding fluorescent dyes
Explanation - Acid‑sensitive bonds (e.g., hydrazone) break in low pH environments, releasing the drug.
Correct answer is: Incorporating acid‑labile linkers that cleave under acidic conditions
Q.107 What does the term “bio‑distribution” refer to in pharmacology?
The pattern of electrical conductivity in tissues
The distribution of a drug or nanocarrier throughout the body's tissues and organs over time
The magnetic field distribution inside the body
The temperature profile of a drug after injection
Explanation - Bio‑distribution studies map where and how much of a therapeutic reaches various organs.
Correct answer is: The distribution of a drug or nanocarrier throughout the body's tissues and organs over time
Q.108 Which of the following nanocarrier designs is most suitable for delivering a volatile, oil‑soluble drug via inhalation?
Solid lipid nanoparticles (SLNs)
Polymeric micelles
Liposomes with aqueous core
Gold nanorods
Explanation - SLNs can encapsulate lipophilic drugs and are compatible with aerosol formulations for pulmonary delivery.
Correct answer is: Solid lipid nanoparticles (SLNs)
Q.109 Why is it important to assess the “hemolysis” potential of a nanoparticle formulation?
To evaluate its magnetic properties
To determine whether it damages red blood cells upon intravenous administration
To measure its electrical conductivity
To assess its fluorescence intensity
Explanation - Hemolysis assays detect membrane disruption of erythrocytes, indicating potential safety issues for IV formulations.
Correct answer is: To determine whether it damages red blood cells upon intravenous administration
Q.110 Which of the following best describes a “hydrogel nanoparticle”?
A rigid metallic sphere
A cross‑linked polymer network that can swell in water and load drugs
A lipid vesicle with multiple bilayers
A magnetic nanoparticle coated with gold
Explanation - Hydrogel nanoparticles absorb water, creating a hydrated matrix suitable for drug encapsulation and release.
Correct answer is: A cross‑linked polymer network that can swell in water and load drugs
Q.111 Which of the following factors most directly influences the “circulation half‑life” of a nanocarrier?
Particle shape
Surface modification with stealth polymers (e.g., PEG)
Color of the formulation
Magnetic susceptibility
Explanation - Stealth coatings reduce opsonization and clearance, extending the time particles remain in blood.
Correct answer is: Surface modification with stealth polymers (e.g., PEG)
Q.112 What is the typical purpose of adding a “fluorescent marker” to a nanoparticle during pre‑clinical studies?
To increase drug loading
To enable tracking of particle distribution via imaging techniques
To improve magnetic responsiveness
To reduce particle size
Explanation - Fluorescent tags allow visualization of nanocarrier biodistribution in cells or animal models.
Correct answer is: To enable tracking of particle distribution via imaging techniques
Q.113 Which of the following is a major challenge when scaling up liposome production for commercial use?
Achieving consistent size distribution and encapsulation efficiency across large batches
Increasing magnetic susceptibility
Changing the color of the liposomes
Reducing electrical conductivity
Explanation - Scale‑up must preserve critical quality attributes such as size, lamellarity, and drug loading.
Correct answer is: Achieving consistent size distribution and encapsulation efficiency across large batches
Q.114 Which of the following nanocarrier characteristics is most important for crossing the intestinal epithelium via paracellular pathways?
Particle size below 50 nm and neutral or slightly positive surface charge
Strong magnetic properties
High electrical conductivity
Metallic core
Explanation - Small, appropriately charged particles can exploit tight junctions for paracellular transport.
Correct answer is: Particle size below 50 nm and neutral or slightly positive surface charge
Q.115 Which analytical technique can provide information about the crystalline vs. amorphous state of a drug within a nanoparticle?
Differential scanning calorimetry (DSC)
Dynamic light scattering (DLS)
Zeta potential measurement
UV‑Vis spectroscopy
Explanation - DSC detects melting endotherms; disappearance indicates an amorphous or molecularly dispersed drug state.
Correct answer is: Differential scanning calorimetry (DSC)