Device and method for in vivo photoacoustic diagnosis and photothermal purging of infected blood

Abstract

A method of non-invasively detecting and purging bacterial cells using a modified photoacoustic in vivo flow cytometer device is described herein. In particular, a method of detecting bacterial cells by analyzing photoacoustic pulses emitted in response to laser pulses from a pulsed laser source and/or selectively destroying the detected bacterial cells using a non-linear photothermal response induced by a high-energy laser pulse is described herein.

What is claimed is: 
     
         1 . A method for detecting a circulating bacterial cell within a vessel of a living organism in vivo, comprising:
 injecting or transfusing at least one contrast agent into the vessel, wherein the at least one contrast agent is functionalized with at least one targeting agent;   contacting the circulating bacterial cell with the functionalized contrast agent;   pulsing an area of interest with at least one pulse of NIR laser energy;   detecting at least one photoacoustic pulse emitted by the bacterial cell; and,   analyzing the at least one detected photoacoustic pulse to indicate the presence of the bacterial cell in circulation.   
     
     
         2 . The method of  claim 1 , wherein circulating bacterial cells are detected at a resolution of at least 1 bacterial cell per 10 8  cells in circulation. 
     
     
         3 . The method of  claim 1 , wherein the at least one contrast agent is selected from the group consisting of: gold nanospheres, gold nanoshells, gold nanorods, gold cages, carbon nanoparticles, perfluorocarbon nanoparticles, carbon nanotubes, spectrally tunable golden carbon nanotubes, carbon nanohorns, magnetic nanoparticles, silica-coated magnetic nanoparticles, quantum dots, binary gold-carbon nanotube nanoparticles, multilayer nanoparticles, clustered nanoparticles, liposomes, micelles, and microbubbles. 
     
     
         4 . The method of  claim 1 , wherein the at least one targeting agent is an antibody, a protein, a ligand for one or more specific cell receptors, a receptor, a peptide, or a wheat germ agglutinin. 
     
     
         5 . The method of  claim 4 , wherein the at least one targeting agent is selected from the group consisting of antibodies to protein A receptors of  Staphylococcus aureus , antibodies to a lipoprotein, ligands to polysaccharide and siderophore receptors of bacteria, and an antibody specific for a protein highly expressed in bacteria but absent in mammalian cells. 
     
     
         6 . The method of  claim 1 , further comprising continuously withdrawing a portion of blood from the vessel of the living organism to an extracorporeal shunt comprising a circulatory bypass tube, directing the portion of blood through the circulatory bypass tube, and returning the portion of blood back into the vessel of the living organism, wherein the area of interest includes a cross-section situated within the circulatory bypass tube. 
     
     
         7 . A method for selectively destroying a plurality of circulating bacterial cells in a vessel of a living organism in vivo, comprising:
 injecting or transfusing at least one contrast agent into the vessel, wherein the at least one contrast agent is functionalized with at least one targeting agent;   contacting the plurality of circulating bacterial cells with the functionalized contrast agent;   detecting one or more of the plurality of circulating bacterial cells;   triggering a pulse of laser energy delivered at a wavelength and energy level sufficient to cause destruction of the one or more detected bacterial cells;   monitoring a frequency of detection of a remaining portion of circulating bacterial cells through the vessel; and,   terminating when the frequency of detection of the remaining portion of circulating bacterial cells falls below a threshold level.   
     
     
         8 . The method of  claim 7 , wherein the one or more of the plurality of circulating bacterial cells are detected using an in vivo flow cytometry device using laser-excited photoacoustic waves emitted by the one or more of the plurality of circulating bacterial cells. 
     
     
         9 . The method of  claim 7 , wherein the threshold level of the frequency of detection ranges between about 10 −3  target objects/min and about 10 2  target objects/min. 
     
     
         10 . The method of  claim 7 , wherein the at least one contrast agent is selected from the group consisting of: gold nanospheres, gold nanoshells, gold nanorods, gold cages, carbon nanoparticles, perfluorocarbon nanoparticles, carbon nanotubes, spectrally tunable golden carbon nanotubes, carbon nanohorns, magnetic nanoparticles, silica-coated magnetic nanoparticles, quantum dots, binary gold-carbon nanotube nanoparticles, multilayer nanoparticles, clustered nanoparticles, liposomes, micelles, and microbubbles. 
     
     
         11 . The method of  claim 7 , wherein the at least one targeting agent is an antibody, a protein, a ligand for one or more specific cell receptors, a receptor, a peptide, or a wheat germ agglutinin. 
     
     
         12 . The method of  claim 11 , wherein the at least one targeting agent is selected from the group consisting of antibodies to protein A receptors of  Staphylococcus aureus , antibodies to a lipoprotein, ligands to polysaccharide and siderophore receptors of bacteria, and an antibody specific for a protein highly expressed in bacteria but absent in mammalian cells. 
     
     
         13 . The method of  claim 7 , wherein a first wavelength is used with a first contrast agent to detect the one or more of the plurality of circulating bacterial cells and a second wavelength is used with a second contrast agent to destroy the one or more detected bacterial cells. 
     
     
         14 . The method of  claim 7 , further comprising continuously withdrawing a portion of blood from the vessel out of the living organism to an extracorporeal shunt comprising a circulatory bypass tube, directing the portion of blood through the circulatory bypass tube, and returning the portion of blood back into the vessel of the living organism, wherein the area of interest includes a cross-section situated within the circulatory bypass tube. 
     
     
         15 . A method for selectively destroying a plurality of circulating bacterial cells in a vessel of a living organism in vivo, comprising:
 injecting or transfusing at least one contrast agent into the vessel, wherein the at least one contrast agent is functionalized with at least one targeting agent;   contacting the plurality of circulating bacterial cells with the at least one functionalized contrast agent;   triggering a pulse of laser energy delivered at a wavelength and energy level sufficient to cause destruction of one or more of the plurality of circulating bacterial cells;   monitoring a frequency of destruction of the plurality of circulating bacterial cells; and,   terminating when the frequency of destruction of the plurality of circulating bacterial cells falls below a threshold level.   
     
     
         16 . The method of  claim 15 , in which the threshold level of the frequency of destruction ranges between about 10 −3  target objects/min and about 10 2  target objects/min. 
     
     
         17 . The method of  claim 15 , wherein the at least one contrast agent is selected from the group consisting of: gold nanospheres, gold nanoshells, gold nanorods, gold cages, carbon nanoparticles, perfluorocarbon nanoparticles, carbon nanotubes, spectrally tunable golden carbon nanotubes, carbon nanohorns, magnetic nanoparticles, silica-coated magnetic nanoparticles, quantum dots, binary gold-carbon nanotube nanoparticles, multilayer nanoparticles, clustered nanoparticles, liposomes, micelles, and microbubbles. 
     
     
         18 . The method of  claim 15 , wherein the at least one targeting agent is an antibody, a protein, a ligand for one or more specific cell receptors, a receptor, a peptide, or a wheat germ agglutinin. 
     
     
         19 . The method of  claim 18 , wherein the at least one targeting agent is selected from the group consisting of antibodies to protein A receptors of  Staphylococcus aureus , antibodies to a lipoprotein, ligands to polysaccharide and siderophore receptors of bacteria, and an antibody specific for a protein highly expressed in bacteria but absent in mammalian cells. 
     
     
         20 . The method of  claim 15 , further comprising continuously withdrawing a portion of blood from the vessel out of the living organism to an extracorporeal shunt comprising a circulatory bypass tube, directing the portion of blood through the circulatory bypass tube, and returning the portion of blood back into the vessel of the living organism, wherein the area of interest includes a cross-section situated within the circulatory bypass tube.