Metal-antibody tagging and plasma-based detection

Abstract

An apparatus and method for characterizing a target, e.g., microbial samples or biological toxins, includes labeling the target with a biomolecular recognition construct and measuring an atomic-spectra signal of the biomolecular recognition construct. The method can include heating the labeled target before measuring the atomic-spectra signal. The atomic-spectra signal can be measured by performing laser-induced breakdown spectroscopy. The atomic-spectra signal can be measured by performing spark induced breakdown spectroscopy. The biomolecular recognition construct can be prepared by tagging a biological scaffolding with a metal atom or ion. In an aspect in which the target includes a microbial sample, the biological scaffolding can include an antibody against epitopes present on bacterial surface, the antibody linked to a heavy metal. In an aspect in which the target includes a biological toxin, the biological scaffolding can include an antibody against the biological toxin linked to heavy metals.

What is claimed is: 
     
         1 . A method for characterizing a target within a sample, the method comprising:
 applying to the sample a biomolecular recognition construct comprising a metal and a molecular recognition scaffold, wherein the molecular recognition scaffold is configured to bind to the target;   generating a plasma of at least some of the sample; and   detecting electromagnetic radiation emitted by the plasma to provide an atomic-spectra signal of the sample.   
     
     
         2 . The method according to  claim 1 , wherein the generating comprises heating at least part of the sample. 
     
     
         3 . The method according to  claim 1 , wherein the generating comprises irradiating at least part of the sample using a laser. 
     
     
         4 . The method according to  claim 1 , wherein the generating comprises applying a spark to at least part of the sample. 
     
     
         5 . The method according to  claim 1 , further comprising:
 determining presence of the metal in the sample based at least in part on the atomic-spectra signal by performing at least one of spectral unmixing or constrained energy minimization (CEM).   
     
     
         6 . The method according to  claim 1 , further comprising:
 preparing the biomolecular recognition construct by bonding the metal to the molecular recognition scaffold, wherein the molecular recognition scaffold comprises a biological scaffold and the metal comprises a metal atom or ion.   
     
     
         7 . The method according to  claim 1 , wherein the target includes a microbe and the molecular recognition scaffold comprises an antibody against epitopes present on a surface of the microbe. 
     
     
         8 . The method according to  claim 1 , wherein the target includes a biological toxin and the molecular recognition scaffold comprises an antibody against the biological toxin. 
     
     
         9 . The method according to  claim 1 , wherein the biomolecular recognition construct is a first biomolecular recognition construct, the metal is a first metal, the molecular recognition scaffold is a first molecular recognition scaffold, and the target is a first target, the method further comprising:
 applying, to the sample, a second biomolecular recognition construct comprising a second metal and a second molecular recognition scaffold, wherein the second molecular recognition scaffold is configured to bind to a second target;   determining presence of the first metal in the sample based at least in part on the atomic-spectra signal;   determining absence of the second metal in the sample based at least in part on the atomic-spectra signal;   determining presence of the first target in the sample based at least in part on the presence of the first metal in the sample; and   determining absence of the second target in the sample based at least in part on the absence of the second metal in the sample.   
     
     
         10 . The method of  claim 9 , further comprising:
 attaching the sample to a silicon wafer; and   washing the second biomolecular recognition construct from the silicon wafer.   
     
     
         11 . An apparatus for characterizing a biological target in a sample, the apparatus comprising:
 a first subsystem configured to apply, to the sample, a biomolecular recognition construct comprising a metal and a molecular recognition scaffold, wherein the molecular recognition scaffold is configured to bind to the target;   a second subsystem configured to generate a plasma using at least some of the sample; and   a third subsystem configured to detect electromagnetic radiation emitted by the plasma to provide an atomic-spectra signal of the sample.   
     
     
         12 . The apparatus according to  claim 11 , wherein the second subsystem comprises a laser. 
     
     
         13 . The apparatus according to  claim 11 , wherein the second subsystem comprises:
 a first electrode;   a second electrode separate from the first electrode; and   a power supply connected to the first electrode and the second electrode, the power supply being configured to selectively produce a spark across the two electrodes.   
     
     
         14 . The apparatus according to  claim 11 , further comprising:
 at least one processor; and   memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:   determining presence of the metal in the sample based at least in part on the atomic-spectra signal by performing at least one of spectral unmixing or constrained energy minimization (CEM).   
     
     
         15 . The apparatus according to  claim 11 , wherein the target includes a microbe and the molecular recognition scaffold comprises an antibody against epitopes present on a surface of the microbe 
     
     
         16 . The apparatus according to  claim 11 , wherein the target includes a biological toxin and the molecular recognition scaffold comprises an antibody against the biological toxin. 
     
     
         17 . A method, comprising:
 applying, to a sample, a biomolecular recognition construct comprising a metal and a molecular recognition scaffold, wherein the molecular recognition scaffold is configured to bind to a target;   generating a plasma using at least some of the sample;   detecting electromagnetic radiation emitted by the plasma to provide an atomic-spectra signal of the sample;   determining presence of the metal in the sample based at least in part on the atomic-spectra signal; and   determining presence of the target in the sample based at least in part on the presence of the metal in the sample.   
     
     
         18 . The method of  claim 17 , further comprising:
 preparing the biomolecular recognition construct by bonding the metal to the molecular recognition scaffold, wherein the molecular recognition scaffold comprises a biological scaffold and the metal comprises a metal atom or ion.   
     
     
         19 . The method of  claim 17 , wherein the biomolecular recognition construct is a first biomolecular recognition construct, the metal is a first metal, the molecular recognition scaffold is a first molecular recognition scaffold, and the target is a first target, the method further comprising:
 applying, to the sample, a second biomolecular recognition construct comprising a second metal and a second molecular recognition scaffold, wherein the second molecular recognition scaffold is configured to bind to a second target;   determining absence of the second metal in the sample based at least in part on the atomic-spectra signal; and   determining absence of the second target in the sample based at least in part on the absence of the second metal in the sample.   
     
     
         20 . The method of  claim 19 , further comprising:
 attaching the sample to a silicon wafer; and   washing the second biomolecular recognition construct from the silicon wafer.