US-12618802-B2 - Transverse alternating current electrophoresis systems and methods

Abstract

A method, comprising: determining electrophoretic mobility associated with a particle in a transverse alternating force microfluidic channel; determining a size of the particle based at least in part on one of Brownian motion of a particle or one or more images of the particle. A system comprising: a microfluidic channel; a plurality of electrodes oriented transverse to the microfluidic channel, the plurality of electrodes comprising an alternating electric field; and a classification system configured to: determine one or more of the following: an electrophoretic mobility associated with a particle in the transverse AC microfluidic channel and/or determine, based at least in part on the electrophoretic motion, and size from image analysis or Brownian motion of a particle or one or more images of the particle, particle shape, particle deformability, for recognition of surface characteristics, such as assaying for receptors and ligands, and to perform electroporation.

Inventors

• Aaron Timperman

Assignees

• THE TRUSTEES OF THE UNIVERSITY OF PENNSYLVANIA

Dates

Publication Date

20260505

Application Date

20240226

Claims (20)

1. 1 . A method, comprising: determining an electrophoretic mobility of a particle passing through a microfluidic channel, based at least in part on subjecting the particle to a transverse alternating force in the microfluidic channel; and optionally, determining a size of the particle based at least in part on one of Brownian motion of the particle or one or more images of the particle.
2. 2 . The method of claim 1 , further comprising determining a shape of the particle, based at least in part on the size of the particle and the electrophoretic mobility of the particle.
3. 3 . The method of claim 2 , further comprising: determining a surface charge of the particle based at least in part on the size of the particle, the electrophoretic mobility of the particle, and the shape of the particle.
4. 4 . The method of claim 3 , further comprising classifying the particle based on one or more of the particle size, the electrophoretic mobility of the particle, the particle shape, or the particle surface charge.
5. 5 . The method of claim 1 , wherein the alternating force comprises at least one of an alternating current, alternating electric field, or an alternating magnetic field.
6. 6 . The method of claim 1 , wherein the Brownian motion of the particle is determined, at least in part, on a motion of the particle in at least one of a portion of the microfluidic channel devoid of the transverse alternating force or a portion of the microfluidic channel in which the transverse alternating force is present.
7. 7 . The method of claim 1 , wherein the transverse alternating force comprises at least one of a sinusoidal wave, a triangular wave, a complex wave, a square wave, or a complex wave with multiple frequencies.
8. 8 . The method of claim 1 , wherein the particle is a first particle, further comprising: determining an electrophoretic mobility of a second particle passing through the microfluidic channel, based at least in part on subjecting the second particle to the transverse alternating force in the microfluidic channel; and optionally, determining a size of the second particle based at least in part on one of Brownian motion of the second particle or one or more images of the second particle.
9. 9 . A system, comprising: a microfluidic channel; a plurality of electrodes oriented transverse to the microfluidic channel, the plurality of electrodes in communication with an alternating electric field source; and a classification system configured to: determine an electrophoretic mobility of a particle, based at least in part on passing the particle through the microfluidic channel; and optionally, determine, based at least in part on one of Brownian motion of the particle or one or more images of the particle, a size of the particle.
10. 10 . The system of claim 9 , wherein the classification system is further configured to determine, based at least in part on the size of the particle and the electrophoretic mobility of the particle, a shape of the particle.
11. 11 . The system of claim 10 , wherein the classification system is further configured to: determine a surface charge of the particle based at least in part on the size of the particle, the electrophoretic mobility of the particle, and the shape of the particle.
12. 12 . The system of claim 11 , wherein the classification system is further configured to classify the particle based on one or more of the particle size, the electrophoretic mobility, the particle shape, or the particle surface charge.
13. 13 . The system of claim 9 , wherein the Brownian motion of the particle is determined, at least in part, on a motion of the particle in at least one of a portion of the microfluidic channel devoid of a transverse alternating electric field or a portion of the microfluidic channel in which the transverse alternating electric field is present.
14. 14 . The system of claim 9 , wherein the electrophoretic mobility is defined, in part, by a velocity of the particle in response to an application of the electric field.
15. 15 . The system of claim 9 , wherein the transverse alternating electric field comprises at least one of a sinusoidal wave, a triangular wave, a complex wave, a square wave, or a complex wave with multiple frequencies.
16. 16 . The system of claim 9 , wherein the particle is a first particle and wherein the classification system is further configured to: determine an electrophoretic mobility of a second particle, based at least in part on passing the second particle through the microfluidic channel; and optionally determine a size of the second particle based at least in part on one of Brownian motion of the second particle or one or more images of the second particle.
17. 17 . A method, comprising: measuring a behavior of a probe subjected to a transverse alternating force in a microfluidic channel at a first point; measuring, at a second point, a behavior of a complex comprising (i) the probe and (ii) a sample contacted to the probe between the first point and the second point; and comparing the behavior of the probe at the first point and the behavior of the probe at the second point.
18. 18 . The method of claim 17 , wherein the behavior is an oscillation.
19. 19 . The method of claim 17 , wherein a change in behavior of the probe between the first point and the second point is indicative of the probe binding to the sample.
20. 20 . The method of claim 17 , further comprising: introducing, in a first branch of the microfluidic channel, the sample; introducing, in a second branch of the microfluidic channel, the probe; and imaging, at a portion of the microfluidic channel where the sample and the probe are contacted, the contacting of the sample and the probe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application No. 63/486,738, filed Feb. 24, 2023, which application is incorporated herein by reference in its entirety for any and all purposes. GOVERNMENT RIGHTS This invention was made with government support under 1808225 awarded by the National Science Foundation. The government has certain rights in the invention. TECHNICAL FIELD The present disclosure relates to the field of microfluidic electrophoresis. BACKGROUND Detection and characterization of particles, whether biological, organic, or inorganic, has become essential in many fields ranging from clinical to environmental analyses. For example, physical properties such as the size and charge of the living particles play an important role in regulating essential biological activities and further serve as a marker for cells' physiological states. Also, an interest in physical characterizations of contaminants such as microplastics in water has grown rapidly as water purification becomes a pressing and important issue. Existing methods of characterization, however, have certain deficiencies. Accordingly, there is a long-felt need in the field for improved methods of particle characterization and for related systems. SUMMARY Detection and characterization of particles, whether biological, organic, or inorganic, has become essential in many fields ranging from clinical to environmental analyses. For example, physical properties such as the size and charge of the living particles play an important role in regulating essential biological activities and further serve as a marker for cells' physiological states. Also, an interest in physical characterizations of contaminants such as microplastics in water has grown rapidly as water purification becomes a pressing and important issue. Aeolian dust from the desert carries a wide range of inorganic particles and micronutrients to the oceans. Regardless of their type, nearly all of these particles have some surface charge. The surface charge of particles is most frequently characterized by measuring the electrophoretic mobility (μep). The electrophoretic mobility is equal to the electrophoretic velocity, which is dependent on particle's size and shape, divided by the electric field (E), i.e. μep=v/E. Particle characterization techniques can be classified as an ensemble or single particle methods, while the most appropriate method for a particular application depends on the analytical needs. For example, ensemble measurement techniques such as laser diffraction and dynamic light scattering (DLS) measure and determine an average or a distribution of the members of the sample population. Ensemble methods can sample much greater numbers of particles than single-particle measurement techniques as they measure numerous particles in parallel. However, ensemble measurement methods cannot interrogate single particles, therefore, these techniques cannot provide the correlation during multi-parameter analyses and cannot be used as a particle sorting method. On the other hand, single particle measurement techniques, including various types of microscopy and Coulter counter, detect and measure individual particles. Although single-particle techniques usually analyze a reduced number of particles compared to ensemble techniques, they record specific characteristics of each particle. Thus, single-particle techniques provide significantly more information than ensemble measurement techniques. Nonetheless, direct characterization of individual particles remains challenging as these methods typically yield a low signal to noise (S/N) ratio, require longer processing time, and have lower sample throughput. Characterization techniques can also be categorized by their measurable particle size range. Microscopy measures the size of single particles, but the measurements are dependent on wavelengths of the light source and sensitive to the optical properties of the particles, such as refractive index and the buffer medium. Another commonly used ensemble measurement method for particle sizing is dynamic light scattering (DLS). DLS uses light scattering to measure Brownian motion and determine particle size distribution. Although DLS is fast and non-invasive, the method is suitable only for spherical particles and struggles with polydisperse samples. A more recent technique called nanoparticle tracking analysis (NTA) couples light scattering and imaging to measure the size of single particles in suspension. However, NTA is appropriate only for nanometer-sized particles with a low seeding density, and high user variability has been reported. Electrophoretic techniques enable measurement of the electrophoretic mobility, which is partially dependent on the particle's surface charge or zeta potential. Electrophoretic light scattering (ELS) is an ensemble measurement technique based on electrophoresis and DLS that measures the electrophoretic mobility