Bio-barcodes based on oligonucleotide-modified nanoparticles

Herein, we report a method that utilizes oligonucleotides as biochemical barcodes for detecting multiple protein structures in one solution (Figure 1). The approach takes advantage of protein recognition elements functionalized with oligonucleotide strands and the fact that hybridization events that result in the aggregation of gold nanoparticles can significantly alter their physical properties (e.g., optical, electrical, mechanical).1-5 The general idea is that each protein recognition element can be encoded with a different oligonucleotide sequence with discrete and tailorable hybridization/ dehybridization properties and a spectroscopic signature associated with the nanoparticles that changes upon melting to decode a series of analytes in a multi-analyte assay. The barcodes herein are different from the ones based on physical diagnostic markers such as nanorods,6 fluorophore-labeled beads,7 and quantum dots8 in that the decoding information is in the form of chemical informatio