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Profacgen offers high-sensitivity DLS services for analyzing hydrodynamic size, size distribution, aggregation, and stability of proteins, antibodies, nanoparticles, and biomolecular complexes.
Based on Brownian motion, DLS measures scattered light to determine diffusion and size distribution (0.3 nm–10,000 nm), excelling where laser diffraction fails below 100 nm. It handles varied sample concentrations, supports zeta potential and MW analysis, and is widely used for proteins, nucleic acids, viruses, and molecular interactions.
Overview of DLS Technology
DLS measures time-dependent fluctuations in scattered light intensity caused by Brownian motion. Autocorrelation analysis of these fluctuations yields the diffusion coefficient, which is converted to hydrodynamic diameter via the Stokes-Einstein equation. Key analytical principles include:
Brownian motion: Random thermal motion of particles in suspension, where smaller particles diffuse faster and larger particles diffuse more slowly, enabling size-dependent discrimination
Hydrodynamic diameter: The effective diameter of a hypothetical hard sphere that diffuses at the same rate as the particle under analysis, incorporating the particle core, surface layers, and associated solvent molecules
Particle size distribution: The relative intensity or volume distribution of particle sizes within a sample, revealing monodisperse, bimodal, or polydisperse populations and detecting minor aggregate species
Figure 1. Basic setup of DLS measurement system. (Hassan et al., 2015)
Our platform also supports temperature-controlled DLS for aggregation temperature determination and stability monitoring. The well-plate design enables simultaneous multi-sample analysis, not just sequential measurement. This approach is widely applied in studying proteins, nucleic acids, and viruses—including ternary complex sizing and protein globule structure. Profacgen provides DLS-based quality control, homogeneity assessment, and physical/chemical treatment evaluation, supporting a one-step protein degrader development platform.
What Can DLS Measure?
Profacgen's DLS platform delivers comprehensive quantitative measurements across the critical quality attributes of biomolecular and nanoparticle samples:
Hydrodynamic Radius (Rh): The effective radius of particles in solution, derived from diffusion coefficients via the Stokes-Einstein relationship, reflecting the true solvated dimensions of macromolecules
Particle Size Distribution: Intensity-weighted, volume-weighted, and number-weighted distributions revealing the full population heterogeneity, from monomeric species through oligomeric intermediates to large aggregates
Polydispersity Index (PDI): A dimensionless metric quantifying the width of the size distribution, where values below 0.05 indicate highly monodisperse samples and values above 0.5 indicate broad heterogeneity requiring further investigation
Aggregation State: Detection and quantification of soluble aggregates, submicron particles, and large assemblies that may impact immunogenicity, efficacy, and shelf-life stability
Sample Homogeneity: Assessment of batch-to-batch consistency, formulation uniformity, and sample preparation reproducibility through replicate size distribution measurements
Colloidal Stability: Temperature-dependent and time-dependent monitoring of particle growth, aggregation onset, and phase separation to inform formulation design and storage condition selection
Our DLS Analysis Services
Profacgen provides specialized DLS analysis services tailored to diverse sample types and development applications. Each service module is optimized for the specific physicochemical properties and analytical requirements of the target molecule class.
Protein Size Characterization
High-resolution hydrodynamic size analysis for recombinant proteins, enzymes, and multi-subunit complexes.
Recombinant proteins: Molecular weight verification, folding state assessment, and aggregation screening for therapeutic and research-grade proteins
Enzymes: Active-site conformation integrity, cofactor binding effects on hydrodynamic size, and thermal stability profiling under catalytic conditions
Protein complexes: Stoichiometry inference, complex dissociation/association monitoring, and homogeneity assessment for protein-protein and protein-nucleic acid assemblies
Antibody Aggregation Analysis
Sensitive detection and quantification of antibody self-association, oligomerization, and particulate formation.
Monoclonal antibodies: Size distribution profiling, colloidal stability assessment, and forced degradation monitoring for IgG1, IgG2, IgG4 subclasses
Bispecific antibodies: Heterogeneity evaluation, chain pairing verification, and assembly state characterization for complex multi-valent architectures
Fc fusion proteins: Fusion domain integrity, linker flexibility effects on hydrodynamic radius, and aggregation propensity under formulation-relevant conditions
Nanoparticle Characterization
Comprehensive size distribution and stability analysis for drug delivery and diagnostic nanomaterials.
Lipid nanoparticles (LNPs): Size distribution, polydispersity, and encapsulation integrity assessment for mRNA and siRNA delivery systems
Polymeric nanoparticles: Hydrodynamic size, core-shell architecture inference, and degradation kinetics monitoring for sustained-release formulations
Drug delivery systems: Colloidal stability under physiological conditions, protein corona formation assessment, and batch release consistency verification
Formulation Screening Studies
Rapid, low-volume screening of buffer conditions, excipients, and stress parameters to optimize stability.
Buffer optimization: pH-dependent size and PDI profiling across formulation matrices to identify conditions minimizing aggregation and maximizing colloidal stability
Excipient evaluation: Surfactant, osmolyte, and stabilizer effect quantification on particle size distribution and thermal aggregation profiles
Stability studies: Real-time and accelerated thermal stress monitoring, freeze-thaw cycle assessment, and agitation-induced aggregation screening
Applications
Our DLS services support a broad spectrum of applications across biopharmaceutical development, manufacturing, and quality assessment:
Biotherapeutic Developability Assessment: Early-stage hydrodynamic size, aggregation propensity, and colloidal stability profiling to identify developable candidates and flag high-risk molecules before resource-intensive investment
Aggregation Risk Evaluation: Sensitive detection of subvisible aggregates, oligomeric species, and particulate formation that may impact immunogenicity, safety, and regulatory compliance
Formulation Development: Rapid screening of buffer systems, pH conditions, excipient compositions, and surfactant concentrations to identify optimal formulations maximizing stability and minimizing aggregation
Comparability Studies: Rigorous side-by-side assessment of size distribution, PDI, and thermal stability profiles to demonstrate equivalence between process changes, manufacturing sites, or biosimilar and innovator products
Quality Characterization: Routine batch release testing, in-process control monitoring, and stability protocol verification with documented precision, accuracy, and system suitability criteria
Sensitive Aggregation Detection: Our advanced instruments detect even minor impurities caused by aggregation, enabling early identification of stability risks before they impact development timelines or product quality.
Minimal Sample Consumption: High-throughput, well-plate-based analysis requires as little as 4 µL per measurement, conserving precious development-stage samples and enabling comprehensive screening campaigns with limited material.
Rapid Turnaround: Simultaneous multi-sample measurement capability, automated data acquisition, and streamlined analysis workflows deliver results within days rather than weeks, accelerating formulation optimization and decision-making.
Experienced Data Analysis: Our technical team combines deep expertise in light scattering physics with extensive biopharmaceutical development experience, ensuring that data interpretation connects analytical results to actionable development decisions.
A therapeutic antibody development program required rapid identification of a stable, manufacturable formulation for a high-concentration monoclonal antibody prone to reversible self-association and subvisible particle formation. Traditional analytical methods were too material-intensive and slow to screen the required formulation space.
Objective:
To execute a high-throughput DLS-based formulation screening campaign evaluating pH, ionic strength, buffer species, and excipient effects on hydrodynamic size, polydispersity, and thermal aggregation temperature, enabling data-driven selection of an optimal formulation within a constrained timeline.
Approach:
Profacgen implemented a DLS screening design using a 96-well plate, testing 48 formulation conditions in duplicate with 8 µL per well. Temperature ramp experiments (25°C to 70°C) identified aggregation onset temperatures, while isothermal monitoring at 40°C assessed kinetic stability. Static light scattering complemented DLS measurements to detect larger aggregate populations. Selected lead formulations were subjected to accelerated stress studies (agitation, freeze-thaw, elevated temperature) with longitudinal DLS monitoring.
Outcome:
The screening identified a histidine-sucrose formulation at pH 6.0 that maintained monomeric size distribution (PDI < 0.08), elevated aggregation temperature (>65°C), and minimal particle growth under all stress conditions. The low-volume, rapid-turnaround DLS approach conserved over 80% of development material compared to traditional methods and compressed the formulation timeline from months to weeks.
A biosimilar development program required rigorous demonstration of physicochemical equivalence between a candidate monoclonal antibody and the reference innovator product, with hydrodynamic size and aggregation profile being critical quality attributes for regulatory submission.
Objective:
To execute a comprehensive DLS comparability study demonstrating equivalent hydrodynamic diameter, polydispersity index, and aggregation propensity between the biosimilar candidate and reference product, supported by appropriate statistical power and system suitability documentation.
Approach:
Profacgen conducted side-by-side DLS measurements using qualified ZentriForce Pharma instrumentation with validated system suitability criteria. Multiple independent batches of candidate and reference products were analyzed across multiple concentrations and temperatures. Statistical equivalence testing (two one-sided tests, TOST) was applied to mean hydrodynamic diameter and PDI values. Temperature-dependent aggregation monitoring confirmed comparable thermal stability profiles. All measurements included appropriate reference standards and control samples to monitor instrument performance.
Outcome:
The biosimilar candidate demonstrated hydrodynamic size and PDI values within the predefined equivalence margin (±5% for size, ±0.05 for PDI) across all conditions and batches. Temperature-dependent profiles were statistically indistinguishable from the reference product. The comprehensive DLS dataset and structured report supported regulatory submission and accelerated the path to clinical development.
Q: What is the difference between dynamic light scattering and static light scattering?
A: Dynamic Light Scattering (DLS) measures time-dependent fluctuations in scattered light intensity caused by Brownian motion, enabling determination of hydrodynamic size and size distribution. Static Light Scattering (SLS) measures the time-averaged intensity of scattered light, which is related to molecular weight and radius of gyration. Profacgen's platform supports both techniques, allowing complementary characterization of size, molecular weight, and conformation.
Q: What sample volume is required for DLS analysis?
A: Our Plate Reader supports measurements with as little as 4 µL per well in 96-well plate format, making it ideal for high-throughput screening and precious sample conservation. Standard cuvette-based measurements typically require 50–100 µL. We can advise on the optimal format based on your sample availability and analytical objectives.
Q: What is the measurable size range for DLS?
A: DLS is capable of analyzing particles in the size range from approximately 0.3 nm to 10,000 nm (10 µm). This range covers small molecules, peptides, and proteins through large protein complexes, viruses, and nanoparticles. For particles larger than 10 µm, complementary techniques such as laser diffraction or nanoparticle tracking analysis may be more appropriate.
Q: How does DLS compare to other particle sizing techniques?
A: DLS excels for sub-micron particles (below 100 nm) where laser diffraction reaches its sensitivity limit due to weak signal and low angular variation. DLS requires minimal sample preparation, operates in native solution conditions, and provides rapid results. Compared to electron microscopy, DLS measures hydrated rather than dried particles, providing more physiologically relevant size information. Compared to analytical ultracentrifugation, DLS is faster and requires less material but provides less resolution for very similar species.
Q: Can DLS detect small amounts of aggregates?
A: Yes. Due to the sixth-power dependence of scattering intensity on particle diameter, DLS is highly sensitive to large aggregate species even when present at low mass fractions. Our high-sensitivity instruments can detect minor impurities caused by aggregation that may be invisible to other analytical techniques, making DLS an essential tool for early aggregation risk assessment and stability monitoring.
Q: What temperature control options are available?
A: Profacgen offers temperature-controlled DLS measurements from 4°C to 85°C. Temperature ramp experiments can determine aggregation onset temperatures (Tagg) and melting transitions (Tm). Isothermal monitoring at constant temperature enables real-time stability assessment. The well-plate-based design allows simultaneous measurement of multiple samples under identical thermal conditions, ensuring robust comparative analysis.
References:
Hassan, P.A.; Rana, S.; Verma, G. Making sense of Brownian motion: colloid characterization by dynamic light scattering. Langmuir. 2014;30(50):15135-15142. doi:10.1021/la503910q
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Figure 1. Basic setup of DLS measurement system. (Hassan et al., 2015)