Monitor and control nanoparticle, biopharmaceutical and polymer production processes by measuring molar mass and size in real time.

Real-Time MALS

Real-time multi-angle light scattering = RT-MALS for PAT

Whereas MALS is traditionally used in the analytical laboratory, it can also be utilized to develop, monitor and control production processes for nanoparticles, biopharmaceuticals and polymers. RT-MALS, which determines molar mass (Mw), radius (R or Rg) and particle concentration in real time, is used in PAT environments to indicate a process endpoint, collect the appropriate fraction or flag deviations from acceptable product attribute values. This technique is implemented with an ultraDAWN™ MALS instrument and OBSERVER software.

Benefits of RT-MALS:

  • Accelerate process development and scale-up
  • Increase yield, reduce overall time until lot release
  • Maintain product quality with confidence

Measure the product, not the process

Traditional PAT monitors process parameters such as concentration, temperature, pH and feedstock. RT-MALS represents a breakthrough in process analytical technology for production of nanoparticles, biopharmaceuticals and polymers: critical quality attributes (CQAs) can be monitored directly, in-line or on-line, for rapid feedback on product attributes and process quality.

RT-MALS is appropriate for advanced products such as polysaccharide antigens, monoclonal antibodies, drug-containing liposomes, viral vectors or gene therapy lipid nanoparticles. It quantifies size, molecular weight and particle concentration., and generates triggers to the process when the values meet or deviate from specified ranges. In conjunction with OBSERVER RT-MALS software, ultraDAWN measures primary CQAs for enhanced yield and quality, when and where it counts most: on the manufacturing floor.



The ultraDAWN RT-MALS instrument is part of the DAWN family of multi-angle light scattering instruments, incorporating detectors at 18 scattering angles plus one for light transmitted through the flow cell. Unlike the DAWN, miniDAWN and microDAWN instruments which are optimized for use with analytical HPLC and UHPLC, ultraDAWN is appropriate for process environments. It is the only MALS instrument that integrates with OBSERVER software, providing solutions for:

  • Macromolecules: Mw (weight-average molar mass) from 103 to 109 g/mol and Rg (rms radius) from 10 to 250 nm
  • Nanoparticles: Z-average radius from 10 to 250 nm and corresponding particle concentration (concentration range depends on particle size)

UltraDAWN offers versatile options for PAT, including:

  • In-line or on-line configuration
  • Process or slipstream flow rates from 0.1 mL/min to 5 mL/min
  • Integration with production control software via OPC

ultradawn, real-time, molar mass determination, molar mass measurement, molar mass analysis, molecular weight measurement, molar mass characterization


OBSERVER acquires real-time multi-angle light scattering data from ultraDAWN, then calculates and reports molar mass, radius, and/or particle concentration, thirty times each minute. When the RT-MALS results deviate from specifications or reach the process endpoint, OBSERVER can send a trigger to control the process, via analog voltage or digitally via OPC.

GMP requirements are fulfilled by operating OBSERVER as an OPC client for SIPAT or DeltaV.


Real-Time Operation

In-line - For continuous processes that take place at flows below 5 mL/min, such as microfluidic drug encapsulation or chromatographic purification steps, in-line RT-MALS provides the shortest feedback loop while the ultraDAWN samples the entire process stream.

ultradawn, in-line monitoring, on-line monitoring

On-line - When processing takes place within a fixed volume such as a homogenizer, or when the process flow is greater than 5 mL/min, a bypass stream is diverted from the manufacturing process to the ultraDAWN. RT-MALS data are produced in near-real-time.

ultradawn, in-line monitoring, on-line monitoring

At-line / Off-line - Accurate molar mass and size measurements with full resolution of molar mass distributions, aggegates and fragments can be carried out at-line using Wyatt’s MALS and RI detectors for UHPLC, microDAWN and microOptilab. These may be coupled to an automated UHPLC sampling front end such as Waters PATrol.

Rapid, automated at-line nanoparticle size and concentration measurements can be set up using the DynaPro Plate Reader.

Off-line - For detailed analysis, products can be characterized by techniques such as SEC-MALS or FFF-MALS. These provide complete, high-resolution distributions of molar mass and size, though not in real time. A standard  DAWN®  MALS instrument is employed along with an SEC system or an Eclipse™ field-flow fractionation system.


The DynaPro Plate Reader can be set up to perform automated, at-line measurements of nanoparticle size and concentration.


A PAT strategy that incorporates ultraDAWN for RT-MALS sees reduced development time and fewer samples sent to off-line analytical labs. With real-time CQA analysis, process margins can be optimized and attribute drifts detected immediately, reducing discarded product and increasing yield.

RT-MALS in Lab R&D

RT-MALS can be implemented early in process development – at pilot plant scales and even smaller, such as regular production of small batches of material for R&D use. Experience with lab-scale RT-MALS paves the way for effective implementation on the production floor.

RT-MALS in Lab R&D

RT-MALS in Scale-up from Lab to Manufacturing

Scaling up often means re-developing the process, requiring off-line analysis of numerous samples collected from intermediate and final steps. RT-MALS greatly accelerates scale-up: it provides real-time feedback, indicating the effect of method tweaks on CQAs, while simultaneously reducing effort and the number of samples analyzed off-line.

Unlike complex at-line PAT devices, ultraDAWN can simply be left in the process flow upon completion of scale up, for continuous or periodic monitoring of the final process.

RT-MALS in Lab R&D

RT-MALS on the Manufacturing Floor

ultraDAWN and OBSERVER software are simple, robust technologies that may be employed in different ways during serial production. During initial stages, technicians can visually monitor molar mass and size, intervening in the process as needed. With increasing confidence in the capabilities and reliability of RT-MALS, engineers may implement fully-automated process control using OBSERVER’s configurable triggers. In both cases, all data can be reviewed post-production to determine if any deviations were encountered.

RT-MALS in Lab R&D

Virus purification

RT-MALS monitors particle radius and triggers when within the specified range, to differentiate from smaller proteins or DNA and larger cell fragments and collect virus-enriched fractions.

Virus purification

TFF concentration

RT-MALS monitors particle concentration in the course of tangential flow filtration. and triggers when above the specified end point, to terminate the process step.

TFF concentration

Polysaccharide depolymerization

RT-MALS monitors molecular weight and triggers when below the specified end point, to terminate the homogenization process.

Polysaccharide depolymerization

Liposome homogenization

RT-MALS monitors radius and triggers if outside the specified range, to divert out-of-spec product from contaminating the collection vessel.

Liposome homogenization