Nanoparticle Antibody Conjugation
Particle-Specific Conjugation StrategyControlled Antibody Surface PresentationIntegrated Purification & Functional Verification
We provide custom nanoparticle antibody conjugation services for research teams developing immunoassays, affinity-capture reagents, imaging probes, biosensors, cell-labeling tools, and targeted nanomaterial systems. Our capabilities cover antibody attachment to gold nanoparticles, silver nanoparticles, magnetic nanoparticles, silica nanoparticles, polymeric nanoparticles, fluorescent nanobeads, quantum dots, and other functionalized particle surfaces.
Projects can begin with customer-supplied antibodies and nanoparticles or with a complete development program that includes particle selection, antibody-format review, surface activation, linker design, conjugation, passivation, purification, physicochemical characterization, and function-relevant testing. Our nanoparticle antibody conjugation workflow can also be coordinated with broader nanoparticles and beads conjugation or antibody conjugation services when a project requires comparative chemistries, multiple particle platforms, or additional antibody modification.
What Problems Can Nanoparticle Antibody Conjugation Solve?
Attaching an antibody to a nanoparticle is not simply a matter of mixing two components. Particle material, coating chemistry, surface charge, antibody format, conjugation site, linker length, antibody density, and working buffer can all affect whether the final conjugate remains dispersed and whether its antigen-binding region is still accessible. A coupling reaction may appear successful by protein measurement while still producing a reagent with weak target binding, excessive background, poor flow behavior, or rapid aggregation.
A properly designed nanoparticle antibody conjugation strategy helps research teams convert a free antibody into a stable, application-compatible nanosurface reagent. The process can address random antibody orientation, steric blocking of the Fab region, loss of binding after chemical modification, uncontrolled particle crosslinking, inconsistent antibody loading, incomplete removal of free antibody, and instability during storage or exposure to assay matrices. It can also help determine whether passive adsorption, covalent coupling, affinity-directed immobilization, or site-selective chemistry is most appropriate for the particle and application.
The development strategy must balance antibody loading with colloidal stability. Higher surface coverage does not automatically provide better performance: excessive antibody density can restrict antigen access, alter particle mobility, increase nonspecific interactions, or destabilize the suspension. Conversely, insufficient coverage may reduce capture capacity or leave exposed particle surfaces that promote background binding. Surface blocking, spacer selection, reaction stoichiometry, and purification therefore need to be planned as part of the conjugation process rather than treated as separate finishing steps.
Key Challenges in Antibody–Nanoparticle Projects
Antibody Binding Declines After Conjugation
Random lysine modification, direct adsorption, harsh activation conditions, or poorly positioned linkers can partially obstruct the antigen-binding region or disturb antibody structure. We review antibody format, available reactive groups, particle surface chemistry, and assay requirements before selecting a coupling route. When orientation is important, Fc-directed, thiol-selective, glycan-directed, or orthogonal handle-based strategies may be considered.
Particles Aggregate During Coupling
Conjugation changes particle charge, hydration, and surface coverage. Aggregation may occur during pH adjustment, carbodiimide activation, antibody addition, centrifugation, buffer exchange, or exposure to salts and proteins. We evaluate reaction concentration, ionic strength, mixing sequence, surface blocking, and purification conditions to identify a practical operating window for the selected particle platform.
Antibody Loading Is Difficult to Control
Antibody input does not directly equal the amount displayed on the nanoparticle. Surface area, particle size, coating density, activation efficiency, antibody accessibility, and purification recovery all influence the final loading level. We use controlled input ratios and appropriate loading assessments to compare candidate conditions and reduce variability between development and repeat batches.
Analytical Data Do Not Predict Assay Performance
A change in hydrodynamic diameter or zeta potential can support evidence of surface modification, but it does not establish that the antibody still recognizes its target. Our characterization plans connect particle measurements with application-relevant tests such as antigen binding, capture response, lateral-flow behavior, cell-surface recognition, pull-down performance, or comparative signal generation.
Free Antibody and Reactive Residues Remain
Unbound antibody, hydrolyzed activation reagents, excess linker, and unstable particle fractions can increase background or interfere with downstream assays. Purification must be selected according to particle size, density, magnetic behavior, sensitivity to centrifugation, and the required final concentration. Options may include magnetic separation, centrifugation, size-exclusion methods, membrane-based exchange, or combinations of these approaches.
Scale-Up Changes Conjugate Behavior
Mixing, surface-to-volume ratio, activation timing, particle concentration, and purification stress can change when a reaction is transferred from a screening batch to a larger preparation. We document critical parameters during development and use staged scale evaluation when a project requires repeat production or larger research quantities.
Our Nanoparticle Antibody Conjugation Services
We support custom antibody-functionalized nanoparticle projects from feasibility assessment through conjugate preparation and analytical review. Service scope is matched to the particle material, surface coating, antibody format, desired orientation, downstream matrix, and required readout. Customer-supplied monoclonal antibodies, polyclonal antibodies, recombinant antibodies, Fab fragments, F(ab')2 fragments, single-domain antibodies, and other affinity proteins can be evaluated for compatibility.
Gold & Silver Conjugation
Scope: Preparation of antibody-functionalized gold or silver nanoparticles for optical detection, electron microscopy, affinity labeling, biosensor development, and particle-based binding studies.
- Direct adsorption, thiol-mediated attachment, linker-assisted coupling, or functional-coating strategies selected according to particle surface and required stability
- Evaluation of particle diameter, surface ligand, plasmonic behavior, antibody isotype, pH, ionic strength, and blocking requirements
- Antibody-density optimization to balance target accessibility, optical response, and colloidal stability
- UV-Vis assessment where appropriate, together with size, dispersion, loading, and binding-related analyses
Deliverables and value: Purified conjugates, preparation records, characterization results, and recommended handling conditions for customers developing custom gold nanoparticle-labeled antibodies or silver nanoparticle-labeled antibodies.
Magnetic Particle Conjugation
Scope: Antibody conjugation to iron oxide nanoparticles, magnetic nanobeads, and functional magnetic particle surfaces used in affinity capture, enrichment, separation, immunoassay development, and cell-labeling research.
- Coupling to carboxyl-, amine-, maleimide-, epoxy-, tosyl-, streptavidin-, or affinity-protein-functionalized magnetic surfaces
- Selection of direct covalent, thiol-selective, biotin-mediated, or Protein A/G-assisted attachment based on antibody and assay design
- Optimization of antibody input, mixing, blocking, magnetic washing, resuspension, and storage buffer
- Assessment of magnetic recovery, free-antibody removal, particle dispersion, and target-capture performance
Deliverables and value: Application-ready research conjugates and a condition summary that supports reproducible use in capture and separation workflows. Related builds can be coordinated with our magnetic bead-labeled antibody service.
Silica & Polymer Conjugation
Scope: Conjugation of antibodies and antibody fragments to silica, polystyrene, latex, hydrogel, PEG-containing, biodegradable polymer, and other coated nanoparticle or nanobead systems.
- Review of available amine, carboxyl, thiol, aldehyde, azide, alkyne, maleimide, or activated-ester surface groups
- Linker and spacer selection to separate the antibody from crowded or hydrophobic particle surfaces
- Control of reaction pH, organic cosolvent exposure, particle concentration, and surface passivation
- Support for fluorescent or reporter-containing particles requiring preservation of optical properties during coupling
Deliverables and value: Purified antibody-coated nanoparticles with physicochemical and functional data selected for the intended biosensor, imaging, binding, or assay-development workflow.
Quantum Dot Conjugation
Scope: Antibody functionalization of water-dispersible quantum dots and coated fluorescent nanocrystals for multiplex imaging, fluorescence detection, cell-labeling, and biosensor research.
- Compatibility review of shell, polymer coating, hydrodynamic size, surface functionality, and emission characteristics
- Covalent or affinity-based attachment using carboxyl, amine, maleimide, biotin, streptavidin, or orthogonal reactive handles
- Conjugation-density control to reduce fluorescence quenching, particle bridging, and restricted antibody accessibility
- Purification planning that minimizes particle loss and separates unbound antibody without compromising dispersion
Deliverables and value: Antibody–quantum dot conjugates, fluorescence and dispersion observations, and functional comparison data where included in the project. Dedicated support is also available through our quantum dot antibody conjugation service.
Oriented Surface Coupling
Scope: Development of antibody-presentation strategies intended to improve Fab accessibility or reduce the heterogeneity associated with random surface attachment.
- Protein A, Protein G, Protein A/G, or related Fc-binding approaches where antibody species and subclass are compatible
- Controlled thiol coupling using antibody fragments, accessible cysteines, or carefully introduced sulfhydryl groups
- Glycan-directed modification or aldehyde-mediated strategies when Fc-region attachment is technically appropriate
- Azide–alkyne, tetrazine–TCO, or other orthogonal coupling routes after compatible handles have been installed
Deliverables and value: Comparative conjugates or an optimized orientation strategy supported by particle, loading, and binding data. The approach is selected case by case because no orientation method is universally compatible with every antibody or nanoparticle surface.
Purification & Characterization
Scope: Removal of free antibody and reaction residues, buffer exchange, concentration adjustment, conjugate stabilization, and analytical review of antibody-functionalized nanoparticles.
- Magnetic separation, controlled centrifugation, size-exclusion separation, ultrafiltration, dialysis, or combined purification workflows
- DLS, zeta potential, UV-Vis, fluorescence, NTA, electron microscopy, electrophoresis, or protein-quantification methods as appropriate
- Antibody-loading estimation, free-antibody assessment, aggregation monitoring, and stability screening
- Function-relevant testing using customer-provided antigen, capture format, cell model, or assay protocol when included in scope
Deliverables and value: Conjugates accompanied by a project-specific analytical summary that helps customers distinguish simple surface modification from a nanoparticle reagent that remains functional in its intended research workflow.
Design Parameters for Nanoparticle Antibody Conjugation
Successful development depends on the interaction between particle properties, antibody chemistry, conjugation conditions, and the intended application. The following parameters are reviewed when building a nanoparticle antibody conjugation strategy.
| Design Parameter | Common Options | Technical Considerations | Effect on Conjugate Performance | Customer Decision Value |
| Nanoparticle Platform | Gold, silver, iron oxide, silica, polymer, latex, fluorescent nanobead, quantum dot | Material determines available surface chemistry, optical or magnetic behavior, density, purification method, and sensitivity to buffer conditions | Influences signal generation, separation behavior, dispersion, loading capacity, and downstream compatibility | Helps select a particle that supports the intended readout rather than forcing one material into every application |
| Particle Size & Coating | Small or large particles, PEG-coated, citrate-stabilized, polymer-coated, protein-coated, carboxylated, aminated | Surface curvature and coating density affect accessible area, antibody packing, steric hindrance, and colloidal stability | Changes antibody loading, hydrodynamic diameter, target access, optical behavior, and flow characteristics | Reduces the risk of choosing a particle size or coating that performs poorly in the final assay format |
| Antibody Format | IgG, polyclonal antibody, recombinant antibody, Fab, F(ab')2, single-domain antibody, Fc fusion | Molecular size, isotype, species, subclass, free thiols, glycosylation, formulation, and target affinity affect method selection | Determines orientation options, surface footprint, loading density, and purification behavior | Allows the conjugation route to be matched to the actual antibody instead of using a generic protocol |
| Attachment Strategy | Passive adsorption, EDC/NHS, activated ester, maleimide–thiol, affinity-directed, biotin–streptavidin, click chemistry | Each method differs in selectivity, orientation control, reaction conditions, linker requirements, and reversibility | Affects bond stability, antibody accessibility, conjugate heterogeneity, and reproducibility | Provides a rational basis for balancing development speed, functional performance, and process complexity |
| Antibody Surface Density | Low, moderate, or high coverage; mixed-ligand surfaces; controlled antibody-to-particle input ratios | Excessive loading can create steric crowding or particle bridging, while insufficient coverage can reduce capture capacity and leave exposed surfaces | Influences avidity, background binding, aggregation, target accessibility, and assay response | Helps identify a usable loading window rather than assuming that maximum antibody input is optimal |
| Linker & Spacer Design | Short linker, PEG spacer, heterobifunctional linker, cleavable or noncleavable linker, affinity adapter | Spacer length and hydrophilicity affect distance from the surface, flexibility, nonspecific adsorption, and reaction accessibility | Can improve antigen access and dispersion but may increase conjugate size or reduce surface packing | Supports informed selection of a linker that addresses the actual source of steric or stability problems |
| Buffer & Passivation | Phosphate, borate, MES, HEPES, low-salt buffers, protein blockers, PEG-based blockers, surfactants | Buffer amines, reducing agents, preservatives, ionic strength, pH, and competing proteins may interfere with coupling or destabilize particles | Affects activation efficiency, aggregation, nonspecific binding, storage behavior, and assay-matrix tolerance | Prevents avoidable failures caused by incompatible antibody formulations or downstream buffer conditions |
Antibody–Nanoparticle Conjugation Methods
Method selection is based on the nanoparticle surface, antibody format, desired orientation, working matrix, and acceptable process complexity. For additional chemistry-selection guidance, customers may review our resources on choosing antibody conjugation chemistry and site-specific versus random antibody conjugation.
| Conjugation Method | Technical Approach | Suitable Particle Surfaces | Advantages | Key Limitations |
| Passive Adsorption | Antibody is immobilized through electrostatic, hydrophobic, and other noncovalent interactions | Citrate-stabilized gold, silver, latex, and selected hydrophobic polymer surfaces | Straightforward setup, limited antibody derivatization, useful for initial feasibility screening | Orientation and loading may be heterogeneous; desorption, aggregation, or activity loss can occur under changing buffer conditions |
| EDC/NHS Coupling | Surface carboxyl groups are activated and reacted with antibody primary amines to form amide bonds | Carboxylated magnetic, silica, polymeric, latex, quantum dot, and coated metal nanoparticles | Widely applicable covalent attachment using common functionalized particle surfaces | Primarily lysine-directed and therefore heterogeneous; activation timing, pH, aggregation, and antibody orientation require control |
| Maleimide–Thiol Coupling | Maleimide-functionalized particles react with native, fragment-derived, or introduced antibody sulfhydryl groups | Maleimide-modified gold, magnetic, silica, polymeric, and fluorescent nanoparticle surfaces | Greater chemoselectivity than general amine coupling and potential for improved site control | Antibody reduction or thiolation must be controlled to avoid structural damage, crosslinking, or excessive heterogeneity |
| Affinity-Directed Attachment | Protein A, Protein G, Protein A/G, or another affinity adapter captures the antibody through its Fc or a defined tag | Affinity-protein-functionalized magnetic, gold, silica, polymer, and fluorescent particles | Can improve Fab exposure and simplify antibody exchange during screening | Binding depends on antibody species and subclass; noncovalent assemblies may require stabilization for demanding conditions |
| Biotin–Streptavidin Assembly | Biotinylated antibody is assembled onto streptavidin-functionalized nanoparticles | Magnetic particles, quantum dots, gold nanoparticles, silica particles, and polymer nanobeads | Modular workflow, strong interaction, convenient for comparing several antibodies on one particle platform | Requires controlled antibody biotinylation; streptavidin adds size and may introduce multivalent crosslinking |
| Click Chemistry Coupling | Complementary azide–alkyne, tetrazine–TCO, or related orthogonal handles are installed on the antibody and particle | Prefunctionalized polymer, silica, magnetic, gold, quantum dot, and hybrid nanoparticle surfaces | High chemical selectivity, flexible linker design, and compatibility with multifunctional particle architectures | Requires handle installation and additional analytical controls; the modification site on the antibody still needs to be considered |
| Glycan-Directed Coupling | Fc-associated carbohydrate groups are selectively modified or oxidized for reaction with compatible hydrazide, aminooxy, or orthogonal surfaces | Appropriately functionalized magnetic, silica, polymeric, gold, and fluorescent nanoparticle coatings | Can position attachment away from the antigen-binding region and improve orientation | Antibody glycosylation and oxidation conditions must be verified; method suitability varies by antibody format |
Characterization of Antibody-Conjugated Nanoparticles
Characterization should confirm more than the presence of protein on the nanoparticle surface. A useful data package examines particle integrity, surface modification, free-antibody removal, loading, colloidal stability, and retained target-binding performance. Analytical scope is selected according to particle material and project goals. Additional background is available in our guide to characterizing antibody conjugates.
| Analytical Category | Possible Methodology | Development Purpose | Typical Project Output |
| Particle Size & Dispersion | DLS, NTA, electron microscopy, or particle-specific sizing methods | Detecting hydrodynamic-size changes, polydispersity, aggregation, and particle integrity after conjugation | Size-distribution data, comparative diameter results, and dispersion observations |
| Surface Charge | Zeta potential analysis | Monitoring surface-state changes after activation, antibody loading, and passivation | Comparative zeta-potential values and interpretation of surface modification trends |
| Optical Properties | UV-Vis absorbance or fluorescence spectroscopy | Assessing plasmon shifts, aggregation, emission retention, spectral changes, or optical-particle concentration | Spectra, peak-position observations, absorbance ratios, or fluorescence comparisons |
| Antibody Loading | Supernatant depletion, protein assay, fluorescent-antibody measurement, or particle-specific quantification | Estimating the amount of antibody associated with the nanoparticle and comparing input conditions | Loading estimate, coupling-efficiency trend, or antibody-per-particle approximation where technically supportable |
| Free Antibody Removal | Protein analysis of wash fractions, electrophoresis, chromatography, or membrane-based assessment | Confirming that unbound antibody and soluble reaction components have been reduced to an acceptable project-specific level | Wash-fraction results, purification comparison, and final preparation observations |
| Conjugate Integrity | SDS-PAGE, native electrophoresis, SEC, microscopy, or orthogonal surface-analysis methods | Evaluating antibody degradation, particle crosslinking, or changes produced by the coupling process | Comparative profiles and notes on conjugate integrity or heterogeneity |
| Colloidal Stability | Salt challenge, pH screening, storage observation, freeze–thaw assessment, or matrix exposure | Determining whether the conjugate remains dispersed under relevant handling and working conditions | Stability trends, recommended buffer conditions, and identified operating limits |
| Functional Binding | ELISA-style binding, target capture, lateral-flow testing, cell-binding comparison, pull-down, or biosensor response | Confirming that antibody attachment has not eliminated target recognition and that the particle supports the intended function | Comparative target-response data for selected conjugation conditions |
| Project Documentation | Structured reporting of particle inputs, reaction conditions, purification, analytics, and handling recommendations | Supporting repeat preparation, method transfer, scale evaluation, and downstream assay development | Conjugation record, analytical summary, and recommended storage or use conditions |
Custom Nanoparticle Antibody Conjugation Workflow
Our workflow is structured around the final research application rather than around a single standard coupling protocol. Each step is used to reduce uncertainty related to particle compatibility, antibody activity, conjugate stability, purification, and repeatability.
Requirements & Application Review
We define the target, antibody format, nanoparticle material, particle size, surface coating, assay matrix, readout mechanism, desired scale, and available analytical controls. Understanding the final workflow helps prevent selection of a chemistry that is convenient to perform but unsuitable for the intended application.
Molecule & Surface Assessment
Antibody formulation, concentration, isotype, available reactive groups, and sensitivity are reviewed together with particle functionality, coating composition, concentration, and dispersion state. Interfering components such as carrier proteins, amine-containing buffers, reductants, azide, glycerol, or surfactants are considered before reaction design.
Strategy & Linker Design
We select passive, covalent, affinity-directed, or site-controlled attachment and define activation conditions, antibody-to-particle input, linker or spacer requirements, passivation approach, and purification route. Comparative screening may be recommended when more than one strategy is technically plausible.
Conjugation & Condition Optimization
Reactions are performed under controlled pH, concentration, mixing, timing, and temperature conditions. Candidate input ratios or blocking conditions can be evaluated to identify a balance among antibody loading, particle dispersion, target accessibility, and process recovery.
Purification, Stabilization & QC
Free antibody and soluble reaction components are removed using a particle-compatible method. The conjugate is transferred into a suitable buffer, adjusted to the required concentration where feasible, and evaluated using selected physicochemical, loading, stability, and functional tests.
Delivery & Scale Support
Final conjugates are supplied with a project-specific preparation and analytical summary. When repeat production or larger research quantities are required, critical parameters from the development stage can be reviewed for staged scale-up, batch comparison, and downstream integration.
Why Choose Our Nanoparticle Antibody Conjugation Services
Particle-Specific Strategy Matching
Gold, magnetic, silica, polymer, silver, and quantum dot platforms do not respond identically to activation, mixing, washing, or storage. We select conjugation and purification conditions according to the actual particle surface instead of applying one generic antibody-labeling protocol to every nanomaterial.
Activity-Focused Surface Design
Antibody orientation, linker position, spacer length, surface density, and blocking are evaluated with target accessibility in mind. The objective is not only to demonstrate protein attachment but to preserve useful antigen recognition after the antibody becomes part of a nanosurface construct.
Integrated Purification & Analytics
Conjugation, free-antibody removal, buffer exchange, dispersion assessment, loading analysis, and functional testing are planned as one connected workflow. This makes it easier to identify whether poor performance originates from coupling chemistry, aggregation, purification loss, or reduced antibody activity.
Flexible Formats & Scale
We support intact antibodies, antibody fragments, single-domain formats, customer-supplied particles, and prefunctionalized nanoparticle platforms. Projects can range from comparative feasibility studies to repeat research batches, with scope adjusted to the amount of material, analytical needs, and downstream workflow.
Applications of Antibody-Conjugated Nanoparticles
Lateral Flow Research
- Gold, colored, fluorescent, or magnetic nanoparticle labels for rapid strip-format assay development.
- Optimization of antibody loading, conjugate-pad release, flow behavior, and nonspecific background.
- Comparative preparation of candidate conjugates for screening capture and detection pairs.
Immunoassay Development
- Antibody-functionalized nanoparticles for plate-based, bead-based, optical, electrochemical, and fluorescence assays.
- Multivalent capture or signal-enhancement research using controlled antibody surface display.
- Support for reducing free-antibody background and improving reagent consistency.
Affinity Capture & Enrichment
- Magnetic antibody nanoparticles for isolation, enrichment, pull-down, and sample-preparation studies.
- Surface-density and blocking optimization for complex protein, cell, vesicle, or particle-containing matrices.
- Evaluation of magnetic recovery, target capture, wash tolerance, and nonspecific adsorption.
Immunogold & Microscopy
- Gold nanoparticle antibody probes for electron microscopy and high-contrast localization studies.
- Selection of particle size, direct or secondary labeling format, and antibody surface coverage.
- Preparation of different particle-size conjugates for multiplex localization research.
Cell Labeling & Sorting
- Magnetic, fluorescent, gold, or quantum dot antibody conjugates for cell-surface recognition studies.
- Particle and linker selection based on steric accessibility, signal requirements, and separation format.
- Comparative testing of conjugates for binding, enrichment, imaging, or cell-interaction workflows.
Biosensor & Nanomaterial Research
- Antibody-functionalized nanoparticles for plasmonic, electrochemical, SERS, fluorescence, and surface-based sensors.
- Integration of antibodies with reporter particles, hybrid nanomaterials, and multifunctional surface architectures.
- Feasibility and optimization support for customer-defined recognition and signal-transduction systems.
Discuss Your Nanoparticle Antibody Conjugation Project
Whether you are developing a new antibody-functionalized nanoparticle, troubleshooting aggregation in an existing conjugate, comparing random and oriented coupling strategies, or preparing a particle reagent for a defined assay or imaging workflow, we provide technically focused support across surface design, conjugation, purification, and characterization.
Share your antibody format, nanoparticle material, surface functionality, target application, desired quantity, and available testing method with our team. We will review the information and propose a project scope aligned with your molecule, particle platform, and decision needs. Contact our scientific team to request a nanoparticle antibody conjugation proposal.
Frequently Asked Questions (FAQ)
How are antibodies conjugated to nanoparticles?
Antibodies may be attached through passive adsorption, EDC/NHS amine coupling, maleimide-thiol chemistry, affinity proteins, biotin-streptavidin assembly, glycan-directed modification, or orthogonal click chemistry. The appropriate method depends on the nanoparticle surface, antibody format, orientation needs, and downstream application.
Which nanoparticles can be conjugated with antibodies?
Common platforms include gold, silver, iron oxide and other magnetic particles, silica nanoparticles, polymeric or latex particles, fluorescent nanobeads, quantum dots, and hybrid particles carrying compatible reactive surface groups.
Should I use random or oriented antibody conjugation?
Random coupling is often simpler and may be adequate when the antibody tolerates lysine modification and the target remains accessible. Oriented or site-controlled approaches are considered when random attachment reduces binding, when surface crowding is a concern, or when greater conjugate consistency is required.
Can you work with customer-supplied antibodies and nanoparticles?
Yes. Customer-supplied materials can be evaluated based on antibody concentration, formulation, isotype, particle composition, particle size, surface coating, functional groups, concentration, and dispersion state. Additional cleanup or buffer exchange may be recommended before conjugation.
How is antibody loading on nanoparticles measured?
Possible approaches include measuring antibody depletion from the reaction supernatant, protein assays, fluorescent-antibody quantification, electrophoresis, chromatography, or particle-specific analytical methods. Results are interpreted with recovery and assay-interference controls where appropriate.
