Spatially-Resolved Dynamic Light Scattering
the technology inside the NanoFlowSizer
Think DLS, but with superior features
Discover Spatially Resolved Dynamic Light Scattering
Spatially Resolved Dynamic Light Scattering (SR-DLS) is the unique measurement principle inside the NanoFlowSizer. It enables real-time nanoparticle sizing directly in your process, even in highly turbid, concentrated and flowing suspensions, without dilution or sampling.
Where conventional DLS needs clear, static samples in cuvettes, SR-DLS is designed for “real-world” conditions in R&D, process development and manufacturing.
Limitations of conventional DLS
If you rely on standard DLS instruments, you may recognize these challenges:
- You often have to dilute samples to get a reliable size result.
- Sampling means breaking sterility or opening a closed system.
- Measurements are usually offline in the lab, so feedback comes too late.
- High turbidity or solids content can make measurements unreliable or impossible. InProcess-LSP
- During continuous or fast processes, you only get intermittent snapshots, not a real-time picture.
The result: particle size – a critical quality attribute – is monitored only occasionally, instead of being continuously controlled.
SR-DLS was developed to remove these limitations and make nanoparticle sizing suitable as a true PAT tool in development and manufacturing environments.
What is SR-DLS in simple terms?
You can think of SR-DLS as “DLS with depth resolution”.
Instead of looking at scattered light from one small, static spot in a clear sample, SR-DLS:
- Sends low-coherence light into the sample.
- Collects scattering information at many positions in depth within the illuminated volume. InProcess-LSP
- Uses advanced algorithms to separate:
- motion caused by Brownian movement (particle size information), and
- motion caused by flow (how fast the liquid is moving).
Because the instrument knows where in the sample the signal comes from, and how particles behave at different depths, it can:
- Correct for flow effects and still determine particle size reliably.
- Filter out multiple scattering, so highly turbid suspensions can still be analyzed without dilution.
You get accurate particle size and size distribution in seconds, even when the sample is flowing and far from optically clear.
Watch how it works:
Start the video by clicking the image:
From principle to practice: SR-DLS in NanoFlowSizer
- One instrument for inline, online, at-line and off-line measurements
- Compatible with a wide range of transparent containers and flow geometries
- Measurement times typically within a few seconds, enabling continuous monitoring
Synergy. Innovation. Excellence.
Why SR-DLS works where other methods struggle
Handles high turbidity without dilution
Thanks to depth-resolved detection and automated selection of clean single-scattering signals, SR-DLS can measure:
- Highly concentrated and optically turbid samples
- Process streams where dilution is not desirable or not possible
- Real formulations and intermediates – not just “lab-prepared” diluted versions
This means no more routine sample dilution just for particle size measurement.
Works directly in flow
Conventional DLS expects the sample to be at rest. SR-DLS is designed to work in flow:
- Measures in tubing, flow cells or vessels in your process line. InProcess-LSP
- Distinguishes between particle motion from flow and from Brownian motion, and corrects for the flow contribution.
- Delivers reliable particle size data even at high flow rates, from low-flow lab set-ups up to production-scale throughputs.
This enables continuous, inline monitoring instead of periodic manual sampling.
Non-invasive and sterile-friendly
SR-DLS measurements with NanoFlowSizer are non-invasive: the optics remain outside the process stream.
This helps you to:
- Maintain closed, sterile or contained systems
- Reduce contamination risk
- Integrate particle size monitoring into existing equipment with minimal modification
SR-DLS therefore supports modern aseptic processing and single-use technologies, where opening the system is undesirable.
EMA/FDA: “one of the greatest challenges in bringing new nanomedicines to market is accurately determining their particle size during manufacturing”
What SR-DLS means for your workflow
By moving from conventional DLS to SR-DLS with NanoFlowSizer, you can:
- See particle size trends in real time
- Shorten feedback loops
- Reduce sampling and lab workload
- Increase process robustness
- Support QbD and PAT strategies
Where SR-DLS makes the biggest difference
SR-DLS is particularly valuable when you:
- Work with LNPs, liposomes, nanoemulsions or other turbid nano-formulations
- Develop continuous or semi-continuous processes (e.g. high-pressure homogenization, mixing, milling)
- Need to monitor particle size in sterile or closed systems
- Want to scale from R&D to manufacturing using the same measurement principle
- Aim to implement PAT-based control and reduce dependence on offline QC testing
The right size, right on time.