MOLECULAR COMPOSITION SOLUTION VIA
Mass Photometry

Label-free analysis of molecular mass, protein oligomeric state, and complex formation.

Fast molecular readouts in solution.

Mass photometry provides a direct, label-free readout of molecular mass distributions in solution. It can show whether a sample is mainly monomeric, forms higher-order oligomers, contains aggregates, or assembles into the expected complex.

At BIMOVIS, we offer mass photometry as a standalone analytical service as well as part of integrated structural biology workflows. It can support questions around sample quality, complex formation, formulation effects, batch comparability, and in-process quality control.

For structural biology projects, mass photometry can also provide an early decision point before cryo-EM, X-ray crystallography, negative stain EM, or further biochemical optimization. This makes it useful both as an independent biophysical readout and as a practical bridge between protein production, sample assessment, and structure determination.

Molecular Mass, Protein Oligomeric State, and Sample Heterogeneity

Mass photometry adds a fast biophysical readout for protein characterization, formulation assessment, comparability studies, and structural biology workflows. It can help determine whether a purified protein, antibody, nucleic acid complex, or macromolecular assembly is present in the expected molecular state.

This is valuable when the question is not only whether a sample is pure, but how it behaves in solution. A protein may contain multiple species, shift between oligomeric states, or form complexes only under certain buffer, concentration, or formulation conditions.

By combining mass photometry data with protein biochemistry and structural biology expertise, BIMOVIS can help assess sample behavior, compare conditions, and define practical next steps for analytical or structural follow-up.

Molecular mass distribution of proteins, antibodies, and complexes
Monomeric state, oligomerization, aggregation, and sample heterogeneity
Complex formation between interaction partners
Comparison of constructs, batches, buffers, or formulation conditions
Formulation effects, and in-process quality control questions
Sample quality assessment before cryo-EM, crystallography, or other structural workflows

How we work.

Project scoping & sample context

We discuss the molecule, expected molecular species and the question the mass photometry experiment should address.

Sample and buffer assessment

We review sample concentration, buffer composition and handling conditions to define a suitable measurement setup.

Measurement setup

Samples are vitrified and screened to assess ice quality, distribution, contrast and suitability for tomography.

Mass photometry measurement

Samples are measured under defined conditions to capture molecular mass distributions and species composition.

Data analysis

We analyse the resulting mass distributions and assign relevant populations such as monomers, oligomers, complexes or aggregates.

Interpretation & next steps

Results are interpreted in the context of the project, sample history and possible analytical or structural follow-up.

Project scoping & sample context

We discuss the molecule, expected molecular species and the question the mass photometry experiment should address.

Sample and buffer assessment

We review sample concentration, buffer composition and handling conditions to define a suitable measurement setup.

Measurement setup

The experiment is planned with appropriate controls, dilution strategy and acquisition conditions for the expected mass range.

Mass photometry measurement

The experiment is planned with appropriate controls, dilution strategy and acquisition conditions for the expected mass range.

Data analysis

We analyse the resulting mass distributions and assign relevant populations such as monomers, oligomers, complexes or aggregates.

Interpretation & next steps

Results are interpreted in the context of the project, sample history and possible analytical or structural follow-up.

Where Mass Photometry applies.

Mass photometry supports standalone analytical questions and integrated structural biology projects where molecular state, complex formation, formulation effects, or sample heterogeneity influence the next scientific or technical decision.

Protein Engineering

Assessment of engineered proteins, variants, or assemblies for oligomeric state, stability, and sample behavior.

Antibody Epitope Mapping

Evaluation of antibody-antigen complex formation and stoichiometry before structural or biophysical follow-up.

Drug Delivery Vector Characterization

Analysis of particle-related systems, assemblies, or formulation-dependent changes where size distribution and heterogeneity matter.

Structure-Based Drug Design

Sample quality and complex formation checks for targets entering structural biology or screening workflows.

AI Structure Model Validation

Experimental context for predicted assemblies, oligomeric states, or protein complexes.

Mass photometry questions.

What kinds of samples are suitable for mass photometry?

The service supports purified proteins, antibodies, nucleic acid-containing complexes, and larger macromolecular assemblies. Mass photometry can assess molecular species such as monomers, oligomers, complexes, and aggregates in solution, making it useful for engineered proteins, antibody–antigen systems, and targets entering structural studies or screening workflows.

How does mass photometry help before cryo-EM or X-ray analysis?

Mass photometry provides an early, label-free assessment of molecular state and sample quality, showing whether a sample is predominantly monomeric, forms the intended complex, or contains aggregates or heterogeneous populations. This can reduce downstream risk by informing construct selection, buffer conditions, and sample preparation before cryo-EM, X-ray crystallography, or negative stain EM.

Can mass photometry compare different constructs, buffers, or batches?

Yes. Mass photometry is well suited for comparing protein preparations, constructs, buffer conditions, formulations, and production batches. Measurements under controlled conditions can reveal differences in oligomeric state, complex formation, aggregation, and sample heterogeneity.

What can mass photometry tell me that concentration or purity measurements cannot?

Mass photometry provides information about the molecular species present in solution, not simply the total amount of protein. A sample can have high purity and concentration while still containing multiple oligomeric states, aggregates, or incomplete complexes. Mass photometry helps distinguish these populations and assess how the sample behaves under defined conditions.

Extend your project.

Protein Production & Purification

Preparation and optimization of protein samples for structural biology, biophysical analysis and complex formation studies.

Cryo-Electron Microscopy (Cryo-EM)

Structural analysis of large complexes and molecular assemblies once sample quality and particle behavior are suitable.

Negative Stain Electron Microscopy

Visual assessment of particles, aggregation, and sample heterogeneity as a complementary readout to mass photometry.

Go deeper in our Knowledge Hub.

Guides, protocols, and reference materials to support your structural biology projects — free to access.

MOLECULAR COMPOSITION SOLUTION VIA Mass Photometry