Revolutionize your particle measurement with OptoFluidic Force Induction

OF2i® stands for OptoFluidic Force Induction. This patented method for the characterization of nanoparticles is a game changer. For the first time you can get particle data continuously, seamlessly and in real-time, statistically relevant and representative of the whole particle population. OF2i® blasts through the limitations of conventional methods for particle characterization and revolutionizes your research and production.

This new principle uses light as a tool to manipulate nanoscaled objects in liquid pumped through a measuring cell. OptoFluidic Force Induction takes the “optical tweezers” principle pioneered by Arthur Ashkin a number of steps further: it focuses a donut-shaped laser through the liquid sample to exert optical force on the particles that pushes them forward and turns them around the beam’s center.

Making a movie – and the importance of a donut

Imagine your child is learning to walk. When they take their very first steps you will want to capture the moment. Will you take some photos or a video? A series of single snapshots will not tell the story as well as a film sequence. This is how the OF2i® method compares to the established methods for particle measurement. Whereas you only obtain short snapshots of the particle behavior using conventional methods (DLS, Laser Diffraction) or a short video of a limited number of particles (with NTA), OptoFluidic Force Induction delivers continuous measurement data in a seamless video stream.

What does this continuous measurement mean?

This huge amount of data recorded by OF2i® over time gives insight into the concentration, size and size distribution of particle populations – and shows changes to these as they happen, in real-time. The online PAT sensor can even be integrated directly into your production plant. Results are delivered continuously with single-particle sensitivity.
Being able to follow sample behavior as (nano)particles react and interact with each other and the sample environment is also groundbreaking for research and development applications. One of our very first research partners, Prof. Tobias Madl at the Medical University of Graz, used the prototype BRAVE B-Curious in his research and was able to directly monitor the processes involved in early biomolecular condensate formation for the very first time. He now has a new BRAVE B-Curious to help further his studies of age-related diseases.

And what about the donut?

The laser used by OF2i® is a vortex laser with a donut-shaped beam. Focusing this donut beam through the liquid sample causes the particles to spin around the beam’s center, moving the particles through the measuring cell on spiral trajectories without them bumping into each other.
(Movies are just better when donuts are involved).

Publication in Physical Review Applied:
"Real-Time Nanoparticle Characterization Through Optofluidic Force Induction"
Šimić et al

OF2i® measures particle size and PSD of polydisperse samples

One of the major challenges in particle characterization is the handling of highly polydisperse and multimodal samples, which are frequently encountered in industrial processes. In our short white paper Analyzing polydisperse systems we demonstrate how the OptoFluidic Force Induction (OF2i®) method characterizes complex polydisperse systems in a continuous and seamless measurement spanning approximately one hour.
The corresponding figure shows:

(a) Measured diameters of a mixture of polystyrene spheres (n = 1.59) with nominal diameters of 203, 401, 600, 789, and 1040 nm over a large measurement time. The contribution of each ensemble is determined by a 1D Gaussian mixture model with five components applied to the histogram on top and highlighted by color.

(b) Total concentration (particles/mL) and

(c) count of each cluster, averaged over a period of tmeas = 180 s. For the smallest particles (203 nm), the concentration is divided by a factor of five for better representation.

Particle size histograms (∆d = 10 nm) obtained after (d) 55, (e) 25, and (f) 15 minutes, indicated by markers on the y-axis in panel (a).

Combining OF2i® with Raman analysis for detecting and identifying nano- and microplastics in liquids

BRAVE Analytics is working on an OF2i®-plus-Raman project with the goal of quantifying the amount and types of plastics in a fluidic environment. This will result in a Raman module for integration into the OF2i® platforms (one for benchtop laboratory analysis and one for the PAT sensor for production monitoring). This short white paper Raman analysis plus OF2i® shows that Raman scattering is sufficient for identifying particles in the micrometer range. We are now concentrating on Raman detection of microparticles and nanoparticles.

The corresponding figure shows:
(a) P1 is a stably trapped single particle, P2 and P3 are agglomerations. The Raman spectra were obtained between the inserted squares
(b) The spectra of a single 5 µm particle sphere (P1), particle agglomerations (P2 and P3) and a reference spectrum of bulk polystyrene measured with a regular Raman microscope.

What do you get with OF2i®?

With OptoFluidic Force induction you get a number of benefits, including speed of results, continuous, real-time and online measurements, detection of extremely low particle concentrations and analysis which is statistically relevant as it considers up to 1000 particles per minute.

You enjoy faster particle analysis in real-time

The OF2i® method delivers faster results than conventional methods for particle characterization. Measurement data is available in real-time and can be monitored live. For the first time, you get insights into particle behavior, formation processes and sample stabilities and results are available instantly. Due to automated cleaning routines you will also save time and money.

You get representative data for the whole particle population

OF2i® also sets new standards in terms of accuracy. From now on it doesn’t matter whether you want to monitor particle behavior for a few seconds or for hours. OF2i® is able to measure around 1000 particles per minute at concentrations ranging from a few particles up to 10⁸ per milliliter. Particle sizes from 50 nm* to 5 µm* (*sample-dependent, a large-particle module up to 50 µm is planned) are detected, which means that measurement results deliver precise and representative data for the whole particle population. OF2i® delivers actual D-values, and even resolves complex, polydisperse samples.

You measure continuously during production

BRAVE Analytics’ PAT sensor integrates into the production plant to deliver insights into particle behavior in real-time. This leads to unprecedented benefits for quality control. As OF2i® is capable of monitoring and controlling the particle behavior during the production process the risk of out-of-spec product is reduced radically and waiting for results from the lab is no longer as critical. With OF2i® you can look inside your product to ensure high quality and monitor the health of your production plant.

You detect ultra-low particle concentrations

Particularly with ultra-low sample volumes as well as the detection of ultra-low particle concentrations OF2i® flexes its muscles. Thanks to the extreme sensitivity of the particle measurement technology OF2i® provides reliable and representative results for sample volumes starting at 20 µL and offers a detection range from 50 nm* to 5 µm* (*sample-dependent). Even a few particles per milliliter can be detected (e.g. for the detection of nanoplastics in water).

Example measurement reports

Browse the insights delivered by OF2i® for these different sample types.

Monodisperse

This measuring report shows a monodisperse sample.

The D-values do not change over time

Monodisperse with agglomerates

This measuring report shows a monodisperse sample with bigger particles / agglomerates.

The Dn50, Dn90 and Dn10 values do not change over time
D[4,3] and D[3,2] are higher because some bigger particles or agglomerates appear (visible in the PSD volume-based graph)

Polydisperse with sedimentation

This measuring report shows a polydisperse sample which is sedimenting out.

Polydispersity shown by SPAN: 3.23
Sedimentation indicated by the decrease in Dn90 over time

Dynamic process occurring

This measuring report shows a dynamic measurement.

Over the first ~18 minutes the particle count is low; Dn90, D[4,3] and D[3,2] jump up and down a lot
At 17:15 the concentration of detected particles increases rapidly; there are no more jumps in the D-Values

Ultra-low concentrations

This measuring report shows an ultra-low concentrated sample.

There are significant changes in the concentration
The D-values are not constant

Explanation of the measurement report

For a detailed explanation of the measuring report read on or get in touch!

All the benefits of OptoFluidic Force Induction particle analysis

Measurement results available within seconds
Real-time particle analysis with instantly observable live data
Measurement of up to 1000 particles per minute
Precise data with single-particle sensitivity - measurement results are fully representative
Can be integrated directly and easily into the production process as an online PAT sensor
Available as a benchtop device
Representative measurement results with ultra-low sample volumes
Measures ultra-low particle concentrations (a few particles per milliliter)
Production control and monitoring without the time delay inherent with lab results

Measuring range can be adapted for each application
Improved efficiency of production processes
Allows predictive maintenance and monitoring the health of the production plant
Central data processing and data collection (H.A.N.S. software)
Meaningful statistical documentation of the measurement results
Easy handling and data interpretation
Deeper understanding of particle behavior
Optional in-flow Raman analysis module for continuous identification of up to 100 particles per minute

OF2i® already simplifies work and optimizes outputs for selected partners

By using the OptoFluidic Force Induction particle size distributions, particle concentrations as well as particle sizes can be monitored in real-time and during production. This groundbreaking technology is used already in various industries, where OF2i® successfully complements or replaces established methods like DLS, NTA, TEM or Laser Diffraction.

When is OF2i® a better alternative to DLS, NTA or laser diffraction?

OF2i® outpaces established particles analysis technologies in a number of ways. Although established methods like DLS, NTA or laser diffraction are well-suited for certain tasks each method has its limits. If you want to understand dynamic processes, resolve complex polydisperse systems or take a closer look at all the particle populations in your sample (with additional in-flow Raman analysis available), OF2i® is an excellent choice. For production processes OF2i® has many benefits as well. OF2i® delivers true online process control with the ultimate goal of achieving real-time release testing and saving time, waste and preventing out-of-spec formulations.

OF2i® is fast.

With OptoFluidic Force Induction results are available in seconds. OF2i® measures up to 1000 particles per minute so results are statistically relevant.

OF2i® measures continuously.

Whereas other methods for particle characterization deliver one-off "snaphots" of particle behavior, OF2i® delivers live measurement data continuously over seconds, minutes or even hours (and 24/7 with the PAT sensor).

OF2i® has single-particle sensitivity.

With OF2i® you can detect and analyze single nanoparticles trapped in the laser beam. The results for particle size, particle size distributions and particle concentration are highly accurate and statistically relevant, even for ultra-low concentrations and ultra-low sample volumes. The results are representative of the entire particle population.

OF2i® measures in real-time.

All measurement results are available as a live data stream in a matter of seconds and allow continuous monitoring of particle behavior. While established methods for the analysis of particles are typically not able to measure online during production, OF2i® delivers true process monitoring 24/7.

Method	DLS	NTA	LD	OF2i®
Integrable into the production process	limited	no	no	yes
Continuous measurement in a lab	no	limited	no	yes
Measurement of particle concentration	limited	limited	no	yes, clearly defined active measuring volume
Measurement of particle size distribution for monodisperse samples	yes	yes	yes	yes
Measurement of particle size distribution for polydisperse samples	difficult	difficult	difficult	yes
Detection range (particle size)	1 nm to 10 µm (sample-dependent)	10 nm to 1 µm (sample-dependent)	10 nm to 3 mm (sample-dependent)	50 nm to 3 µm (sample-dependent)
Monitoring of dynamic processes	limited	limited	no	yes
Continuous particle identification with in-flow Raman analysis	no	no	no	yes

How OF2i® was invented

It started with a problem

Christian Hill, now CEO and CTO of BRAVE Analytics, was frustrated with the particle analysis methods he was using in experiments for his PhD research. Looking around for alternatives, he found research by Arthur Ashkin describing the “optical tweezers” principle Ashkin invented to trap particles using a tightly focused laser beam. Chris began to wonder how this idea might be used to get a better look at particles. After spending many hours thinking about this theory, reading and thinking some more, Chris was motivated to create a laser setup in a small laboratory on the Medical University of Graz campus.

What started with the answer

The end result was a new and patented method for particle analysis: OF2i® (OptoFluidic Force Induction) method. OF2i® is a completely new approach to characterizing particles and nanoparticles. It delivers measurement results for nanoparticle size, nanoparticle size distribution as well as nanoparticle concentration – in a continuous and time-resolved way – and the PAT sensor even measures online during production processes.

How OF2i® overcomes the limits of Brownian motion

OptoFluidic Force Induction takes the “optical tweezers” principle pioneered by Arthur Ashkin a number of steps further: it focuses a donut-shaped laser through the liquid sample to exert optical force on the particles that pushes them forward and turns them around the beam’s center.

Why trap and accelerate?

OF2i® traps the nanoparticles but allows them to continue moving along their spiral trajectories. Accelerating the particles means they are no longer displaying Brownian motion, their movement is much faster and, in fact, the speed of their movement correlates with their particle size. Keeping the particles on their own trajectories minimizes interparticle collisions that would disrupt measurement and makes it easy to follow the particles as they accelerate. In the OF2i® setup a microscope records the velocity change due to these optical forces which is used to calculate the particle size.

Publication in Physical Review Applied:
"Theoretical Description of Optofluidic Force Induction"
Šimić et al

Free OF2i® Guide

Would you like to learn more about particle characterization techniques and OF2i® in particular?
We have a handy paperback book for you!
Register for a free “OF2i® Guide” and we will send it to you by post.

Chapters include:

classifications of particle size, particle shape, particle concentration and PSD
an overview of Brownian-motion-based techniques, scattering-based techniques and our patented Optofluidic Force Induction principle
the theory behind OF2i®’s data processing

Send your name and address to:

curious@braveanalytics.eu

Benefits of the OF2i® method and groundbreaking features

We already collaborate with selected companies and universities which now use OF2i® technology to achieve groundbreaking results in their production and research. These brave pioneers use our patented method for nanoparticle characterization to get a step ahead of their competitors and reach new levels in their research. If the conventional methods for particle measurement limit your research or you want to increase the efficiency of your production, we are happy to present our revolutionary method in a live demonstration. Our experts will answer all your questions and discuss further steps.

Learn more about OF2i® and become a first mover.