A method for identifying a predefined target organism includes extracting a nucleic acid from a sample to form an extracted nucleic acid, amplifying the extracted nucleic acid to form a nucleic acid amplicon, tagging the nucleic acid amplicon with a capture probe and a detector partner to form a detector partner-nucleic acid amplicon-capture probe complex, and performing a detection assay on the detector partner-nucleic acid amplicon-capture probe complex to identify whether the predefined target organism is present in the sample.

Assays using nanoparticle probes can be used to detect a target oligonucleotide with digital resolution by measuring the peak wavelengths and/or peak intensities of resonantly reflected light from locations on the surface of a photonic crystal (PC). The PC is functionalized with a capture oligonucleotide that binds to a nanoparticle probe that has bound to the target analyte. The binding of the nanoparticle probe to the PC shifts the peak wavelength and reduces the peak intensity of the resonantly reflected light at the binding location. An example nanoparticle probe includes a metallic nanoparticle conjugated to a probe oligonucleotide bound to a protector oligonucleotide. The probe oligonucleotide includes a first portion complementary to the target oligonucleotide and a second portion complementary to the capture oligonucleotide. The target oligonucleotide can bind to the probe oligonucleotide and displace the protector oligonucleotide, which exposes the second portion and enables binding to the capture oligonucleotide.

Assays using nanoparticle probes can be used to detect a target oligonucleotide with digital resolution by measuring the peak wavelengths and/or peak intensities of resonantly reflected light from locations on the surface of a photonic crystal (PC). The PC is functionalized with a capture oligonucleotide that binds to a nanoparticle probe that has bound to the target analyte. The binding of the nanoparticle probe to the PC shifts the peak wavelength and reduces the peak intensity of the resonantly reflected light at the binding location. An example nanoparticle probe includes a metallic nanoparticle conjugated to a probe oligonucleotide bound to a protector oligonucleotide. The probe oligonucleotide includes a first portion complementary to the target oligonucleotide and a second portion complementary to the capture oligonucleotide. The target oligonucleotide can bind to the probe oligonucleotide and displace the protector oligonucleotide, which exposes the second portion and enables binding to the capture oligonucleotide.

The invention displays aflatoxin B.sub.1 (AFB.sub.1) detection kit and AFB.sub.1 detection method. The invention belongs to the technical field of detecting harmful substances. The AFB.sub.1 detection kit was fabricated with DNA walker structure, endonuclease, hairpin H1 and H2. The AFB.sub.1 detection kit has benefits of high sensitivity and short detection time based on signal amplification strategy of DNA Walker structure and hyperbranched fluorescent nanotrees. The present invention can realize high sensitive and rapid detection of AFB.sub.1.

The invention displays aflatoxin B.sub.1 (AFB.sub.1) detection kit and AFB.sub.1 detection method. The invention belongs to the technical field of detecting harmful substances. The AFB.sub.1 detection kit was fabricated with DNA walker structure, endonuclease, hairpin H1 and H2. The AFB.sub.1 detection kit has benefits of high sensitivity and short detection time based on signal amplification strategy of DNA Walker structure and hyperbranched fluorescent nanotrees. The present invention can realize high sensitive and rapid detection of AFB.sub.1.

The present invention provides compositions and methods for colorimetric detection schemes for detecting a variety of biomolecules. The compositions and methods employ DNA hybridization chain reaction for catalytic aggregation of gold nanoparticles. In this catalytic aggregation scheme, a single target DNA strand triggers the formation of multiple inter-particle linkages in contrast to the single linkage formed in conventional direct aggregation schemes.

The present invention provides compositions and methods for colorimetric detection schemes for detecting a variety of biomolecules. The compositions and methods employ DNA hybridization chain reaction for catalytic aggregation of gold nanoparticles. In this catalytic aggregation scheme, a single target DNA strand triggers the formation of multiple inter-particle linkages in contrast to the single linkage formed in conventional direct aggregation schemes.

Provided herein are systems and methods for using DNA polymerases to record information onto DNA for single cell high time-resolution recording and for high density data storage. The technology provides a DNA polymerase-based nano scale device that can be genetically encoded to record temporal information about the polymerase's environment into an extending single stand of DNA.

Provided herein are systems and methods for using DNA polymerases to record information onto DNA for single cell high time-resolution recording and for high density data storage. The technology provides a DNA polymerase-based nano scale device that can be genetically encoded to record temporal information about the polymerase's environment into an extending single stand of DNA.

Provided for herein is a method for detecting the presence of a nucleic acid target molecule in a biological sample. In certain aspects, the method comprises contacting a test sample that comprises (i) a biological sample comprising a nucleic acid target molecule and (ii) an osmylated single-stranded oligonucleotide probe comprising at least one pyrimidine residue covalently bonded to a substituted or unsubstituted Osmium tetroxide (OsO.sub.4)-2,2′-bypyridine group (OsBp group).