Dynamic Characterization of Particles With Flow Cytometry

Abstract

Flow cytometry concepts are modified to enable dynamic characterizations of particles to be obtained using optical scattering data. Particles in flow will be introduced into a sample volume. Light scattered by a particle in the sample volume is collected and analyzed. What differentiates the concepts disclosed herein from conventional flow cytometry is the use of an acoustic source that is disposed to direct acoustic energy into the sample volume. As the particle passes through the sample volume, it responds to the acoustic energy, causing changes in the light scattered by the particle. Those changes, which are not measured during conventional flow cytometry, can be analyzed to determine additional physical properties of the particle.

1 . (canceled) 
     
     
         2 . A method of separating a first sample population from a sample solution including the first sample population and a second sample population different than the first sample population, the method comprising:
 inputting the sample solution in a fluid flow channel;   using an energy source to administer an energy pulse to the sample solution as the sample solution flows through the fluid flow channel; and   separating particles of the first sample population from the sample solution as the sample solution flows through the fluid channel based on a reaction of the particles to the energy pulse.   
     
     
         3 . The method of  claim 2 , further comprising collecting a dynamic scattering intensity profile of the particles while the particles react to the energy pulse and wherein separating particles based on the reaction comprises separating based on the collected dynamic scattering intensity profile of the particles. 
     
     
         4 . The method of  claim 3 , wherein collecting the dynamic scattering intensity profile of the particles comprises illuminating the particles with a light source and capturing light scattered from the particles as the particles react to the energy pulse. 
     
     
         5 . The method of  claim 3 , wherein separating particles based on the reaction comprises comparing the collected dynamic scattering intensity profile to a database of dynamic scattering intensity profiles and identifying the particles based on the comparison. 
     
     
         6 . The method of  claim 2 , wherein the energy pulse is administered to the sample solution constantly as the sample solution moves through the fluid flow channel. 
     
     
         7 . The method of  claim 2 , wherein the energy pulse is initially administered to a particle in the fluid flow channel as the particle enters a region of interest of the fluid flow channel and then terminated as the particle travels through the region of interest. 
     
     
         8 . A method of modifying a flow cytometer having a sampling volume, a light source for illuminating a sample within the sample volume at a region of interest, and a light sensor for detecting light scattered from the region of interest, the method comprising:
 incorporating a pressure generator with the flow cytometer so that the pressure generator induces pressure changes in the sampling volume when energized.   
     
     
         9 . The method of  claim 2 , wherein the pressure generator generates pressure changes in the sampling volume prior to the region of interest of the sampling volume. 
     
     
         10 . The method of  claim 2 , wherein the pressure generator generates pressure changes in the sampling volume at the region of interest of the sampling volume. 
     
     
         11 . The method of  claim 2 , wherein the pressure generator comprises an ultrasound device. 
     
     
         12 . The method of  claim 2 , wherein the pressure generator is coupled to an external face of the sampling volume and is acoustically coupled the sampling volume. 
     
     
         13 . The method of  claim 2 , wherein the pressure generator is coupled to an internal face to the sampling volume. 
     
     
         14 . The method of  claim 2 , further comprising incorporating a pressure sensor to measure pressure in the sampling volume and to generate a pressure signal in response to measured pressure. 
     
     
         15 . The method of  claim 14 , wherein the pressure sensor comprises a hydrophone. 
     
     
         16 . The method of  claim 14 , further comprising coupling the pressure sensor with the light sensor of the flow cytometer such that the light sensor captures scattered light and generates a scattered light signal in response to the pressure signals generated by the pressure sensor. 
     
     
         17 . The method of  claim 2 , wherein the flow cytometer further comprises a particle sorter, and wherein the method further comprises modifying the particle sorter to sort particles based on a scattering intensity profile collected while particles react to a pressure wave generated by the pressure generator. 
     
     
         18 . A method of separating first particles from a particle sample having first particles and second particles different from the first particles, the method comprising:
 collecting a scattering intensity profile associated with a first particle of the particle sample while the first particle reacts to a pressure wave;   sorting the first particle from an unsorted portion of the particle sample based on the collected scattering intensity profile.   
     
     
         19 . The method of  claim 18 , further comprising:
 delivering the particle sample to a sampling volume with a region of interest;   inducing a pressure change in the sample volume by administering the pressure wave so that the first particle from the particle sample exhibits a reaction to the pressure change as the first particle enters the region of interest;   illuminating the first particle in the region of interest with a light source; and   collecting the scattering intensity profile of the first particle.   
     
     
         20 . The method of  claim 19 , wherein the pressure wave is administered during the collection of the scattering intensity profile. 
     
     
         21 . The method of  claim 19 , wherein the pressure wave is administered initially to excite the first particle as the first particle enters the region of interest and then terminated as the first particle travels through the region of interest of the sampling volume. 
     
     
         22 . The method of  claim 18 , wherein sorting the first particle from the unsorted portion of the particle sample comprises, comparing the collected scattering intensity profile to previously determined dynamic scattering intensity profiles and identifying the first particle based on the comparison. 
     
     
         23 . A system for analyzing particles within a sample, the system comprising:
 a fluid channel having a region and a sample inlet upstream from the region;   an acoustic transducer acoustically coupled with the fluid channel and configured to administer an acoustic wave to the sample as the sample flows within the fluid channel prior to or at the region;   a light source for illuminating the sample at the region;   a light sensor for detecting light scattered from the sample in response to being illuminated by the light source, the light sensor configured to generate a signal in response to the detected scattered light;   a processor configured to analyze the signal from the light sensor to determine one or more characteristics of particles within the sample.   
     
     
         24 . The system of  claim 23 , wherein the fluid channel is defined by an interior and an exterior, and wherein the acoustic transducer is acoustically coupled to the exterior of the fluid channel. 
     
     
         25 . The system of  claim 23 , wherein the fluid channel is defined by an interior and an exterior, and wherein the acoustic transducer is acoustically coupled to the interior of the fluid channel. 
     
     
         26 . The system of  claim 23 , further comprising a pressure sensor coupled with the fluid channel and configured to measure a pressure of the sample at the region and generate a signal in response to measured pressures. 
     
     
         27 . The system of  claim 26 , wherein the pressure sensor is coupled with the light sensor such that the light sensor is triggered to capture scattered light in response to the signals from the pressure sensor. 
     
     
         28 . The system of  claim 23 , further comprising one or more reservoirs branching from the fluid channel downstream from the region. 
     
     
         29 . The system of  claim 28 , further comprising a particle sorter coupled with the fluid channel and positioned downstream from the region and upstream of the one or more reservoirs, the particle sorter configured to sort particles into the one or more reservoirs. 
     
     
         30 . The system of  claim 29 , wherein the processor is configured to determine dynamic scattering intensity profiles of particles in the sample based on the signal from the light sensor, and wherein the particle sorter is configured to sort the sample based on the dynamic scattering intensity profiles of particles in the sample. 
     
     
         31 . A method of measuring characteristics of a particle in a particle sample, the method comprising:
 agitating the particle sample so that the particle of the particle sample undergoes a physical property change;   interrogating the particle while the particle undergoes the physical property changes with a light source;   capturing light scattered by the particle while the particle is interrogated by the light source and as the particle undergoes physical property changes;   generating a light scatter signal in response to the captured scattered light;   identifying a physical characteristic of the particle by processing the light scatter signal.   
     
     
         32 . The method of  claim 31 , wherein the physical property change comprises an increase in size of the particle. 
     
     
         33 . The method of  claim 32 , wherein the physical property changes comprises an oscillation in size of the particle. 
     
     
         34 . The method of  claim 31 , wherein the particle sample is agitated using an acoustic transducer. 
     
     
         35 . The method of  claim 31 , further comprising measuring pressure changes of the particle sample and identifying a physical characteristic of the particle based in part on the pressure changes. 
     
     
         36 . The method of  claim 35 , wherein the capturing of light scattered by the particle is triggered by a measured pressure change. 
     
     
         37 . The method of  claim 31 , wherein processing the light scatter signal comprises computing a power spectral density of the light scatter signal. 
     
     
         38 . The method of  claim 31 , wherein identifying a physical characteristic of the particle comprises identifying ratio of a maximum radius and an ambient radius of the particle in the particle sample and identifying whether the particle is breaking up based on the ratio.