Revolutionize your measurement with OptoFluidic Force Induction
Our patented method for the characterization of nanoparticles truly 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 research and production.
OF2i® stands for OptoFluidic Force Induction. This new principle uses light (the optical forces) as a tool to manipulate nanoscaled objects in liquid pumped through a measuring cell (the fluidic forces). 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.
How OF2i compares to other methods
In comparison to established particle characterization methods which are based on Brownian motion, OF2i® is considerably faster. Tracking every single particle trapped in the laser beam also allows measurements with single-particle accuracy, meaning the results are representative of all the particle fractions and not just an average value calculated across all sample properties. As OF2i is not dependent on Brownian motion to measure nanoparticles it is suddenly possible to get measurement results like never before.
Let’s assume you want to tell a picture story. A series of single snapshots can never tell the story in as much detail as a video can. 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. This huge amount of data recorded 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 BRAVE B-Continuous 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 customers, 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.
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).
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.
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 hundreds of particles per second (depending on the module, that is between 2500 and 4000 particles per minute) at concentrations ranging from a few hundred particles up to 10⁸ per milliliter. Particle sizes from 50 nm* to 5 µm (*sample-dependent and from 20 nm with the PAT sensor, 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.
BRAVE B-Continuous is an online PAT sensor which 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.
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 and from 20 nm with the PAT sensor). Even a few particles per milliliter can be detected (e.g. for the detection of nanoplastics in water).
Discover the benefits of OF2i
While established particle analysis technologies are based on Brownian motion and therefore subject to restrictions and irregularities, OF2i goes one step further and accelerates nanoparticles with defined fluidic and optically induced forces. With OF2i a laser beam propagates through a flow cell. In this case it only takes minimal photonic forces to accelerate, decelerate or redirect the nanoparticles regardless of their Brownian motion. By using an ultramicroscopic setup OF2i can obtain the intensities from single particle light scattering, the single particle trajectories and the particle number per transported volume. With the obtained data the opto-fluidic force induction technology is able to determine particle sizes, particle size distributions and particle concentration continuously and in real-time – and all this with a throughput of up to 4000 particles per minute.
The basic structure of the OF2i nanoparticle measurement technology consists of a laser (532 nm linear polarized CW DPSS with a maximum output power of 2W), a microfluidic channel and an ultramicroscope (10x PLAN microscope objective). First nanoparticles are pumped through a liquid in a cylindrical flow cell. Then a weakly focused vortex or Laguerre-Gaussian laser beam with an orbital angular momentum (OAM) is focused through the sample. The laser exerts optical forces on the nanoparticles so they move along spiral-shaped trajectories, this reduces collisions between particles to a minimum. The nanoparticles excited by the laser beam scatter the light, which is monitored by the ultramicroscope objective and recorded by a CCD camera at a rate of 200 frames per second. In addition OF2i gathers information about the scattering cross-sections and uses particle tracking to determine the velocities of the individual particles. A computer controls laser output power and the fluidic flow.
Mie theory describes the scattering phenomena of electromagnetic waves on spheric particles. For the OF2i principle we have developed a theoretical model for Mie scattering of a spherical nanoparticle excited by a Laguerre-Gaussian laser beam. This requires a multipole expansion of the electromagnetic fields in terms of spherical Bessel and Hankel functions as well as vector spherical harmonics. The electromagnetic fields outside of the nanosphere can then be represented by the multipole coefficients an, bn, where n labels the different spherical degrees and orders. Against this background the theoretical principle of OF2i can be described in three steps.
Step 1:
Step 2:
By employing the usual Mie coefficients we compute the coefficients an, bn for the scattered electromagnetic fields.
Step 3:
Finally, from the sum of incoming and scattered electromagnetic fields, we compute the force acting on the spherical nanoparticle using the analytic expressions given in R. Gutierrez-Cuevas, N. J. Moore, and M. A. Alonso, Phys. Rev. A 97, 053848 (2018).
As soon as the laser beam reaches the nanoparticles in the sample, they are trapped and move along the intensity maxima of the vortex beam. Nanoparticles that have not been trapped by the beam are transported by the fluid in the transverse direction. With OptoFluidic Force Induction we can distinguish three types of trajectories.
I.
If nanoparticles are trapped from the beginning and are accelerated by the optical forces their velocity curves are in almost perfect agreement with the maxima of the experimental velocity histograms.
II.
There are also nanoparticles that initially do not move along the intensity maxima but these are deflected by the optical forces and finally become trapped while propagating down the flow channel.
III.
Finally there are nanoparticles that are not trapped by the laser or the optical forces. They do not scatter light and remain dark in the analysis algorithms. This clear physical definition of our "active measuring volume" allows a defined detection and measurement of the particle concentration.
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 Raman analysis coming soon), 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 measures faster.
With the OptoFluidic Force Induction you get 10x faster results compared to Nanoparticle Tracking Analysis and also much faster results compared to Dynamic Light Scattering and Laser Diffraction. OF2i measures up to 4000 particles per minute.
OF2i measures continuously.
While DLS, TEM, LD and 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 measures more accurately.
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 5 µm (sample-dependent)
|
|
Monitoring of dynamic processes
|
limited
|
limited |
no |
yes
|
You want to see particles like never before?
Learn more about OF2i. We will answer all of your questions.
Our revolutionary OF2i method is currently available in two different products. BRAVE B-Curious is a benchtop nanoparticle analyzer for continuous, time-resolved characterization of nanoparticles in the lab. It also measures and captures ultra-low particle concentrations. BRAVE B-Continuous is an online PAT sensor which can be directly integrated into your production plant to monitor and control the manufacturing process. Both products provide new insights into particle behavior and will revolutionize your research and production.
If you characterize nanoparticles, do you want more meaningful and continuous insights into particle behavior? This is not easy to achieve with current methods. With BRAVE B-Curious you get a nanoparticle analyzer that shows you what is really happening inside your samples – as it occurs. Our benchtop nanoparticle analyzer even measures ultra-low concentrations and delivers representative results for the whole particle population. We are convinced that BRAVE B-Curious is on its way to revolutionize many fields of research.
Especially in the production and monitoring of pharmaceutical emulsions, infusions, vaccines or pain killers, exact particle size distributions have be monitored and guaranteed. The BRAVE B-Continuous PAT sensor is already delivering results in a pilot plant for optimizing the production of total parenteral nutrition (TPN) formulations produced in high-pressure homogenization steps. The lab device BRAVE B-Curious is successfully used for research on liposomes, proteins, vaccines and virus-like particles.
Why OF2i?
Due to OF2i’s single-particle sensitivity and its ability to resolve even complex, polydisperse systems it is delivering pioneering results in biotech and pharmaceutical applications.
When producing cosmetics products such as sunscreens, the EU requires nanoparticles below a certain size to be declared on the labeling. With OF2i you can produce cosmetics that just contain particle sizes up to the limit and not below.
Waste water that is led back into rivers or seas must be analyzed meticulously to ensure it has no negative affects on the environment. Bottled and tap water also have to comply with strict regulations. Whether waste water, bottle water or tap water, OF2i detects even the smallest nanoplastic particles, viruses, bacteria, antibiotics or other contaminations.
Why OF2i?
No other method for particle characterization is capable of detecting ultra-low concentrations in waste water or drinking water with this degree of sensitivity.
Whether researching biomolecular condensate formation, drug dissociation and dissolution or the production of virus-like particles OF2i gives insights into the processes unlike anything seen before. OF2i makes it possible to monitor kinetic processes such as the formation and size distribution of proteins, lipids and extracellular vesicles over time.
Why OF2i?
Of all the methods for particle characterization only OF2i is able to monitor sample kinetics seamlessly and continuously over time.
The possibilities of OF2i are endless for industrial research. In the case of chemical-mechanical-planarization and polishing, for example, the particle size distribution of the CMP slurry is a critical parameter for the success of the process. OF2i is well-suited to detecting large-particle tails in the slurry. OF2i also contributes to online quality control of nanocomposite electroplating processes in order to obtain a more homogeneous particle size distribution, reduced particle size, and upgraded final products.
Why OF2i?
With OF2i you obtain more accurate measurement results of particle sizes, particle size distributions and representative data for the whole particle population. This minimizes critical problems during production processes and reduces rejects. In the field of electroplating OF2i can monitor nanoparticle concentrations continuously in the electrolytic bath.
Hydroxyapatite nanocrystals are used for the treatment of bone defects and for the remineralization of tooth enamel. For online quality control during the production of these crystals the OF2i method has been implemented as a PAT sensor.
Why OF2i?
OF2i has many benefits in the field of online quality control. Hydroxyapatite nanocrystals can be monitored and controlled during production. The gathered measurement results are representative for the whole particle population and are displayed continuously.
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.
PARTICLE MEASUREMENT
As a partner in the MOZART project (MOZART for safe & sustainable by-design metallic coatings & engineered surfaces (RIA)), we received funding from the European Commission as part of the EU Horizon 2020 program.