The central hypothesis of the Phase I effort was that if a material could be synthesized that could emit millions of unique, resolvable optical signatures, and biomolecules such as DNA could be firmly attached to them, that this deeply multiplexed bead set could form the basis of a """"""""suspension array"""""""" where the optical designator of each encoded particle uniquely identifies a given bead. Once each bead is identifiable via its optical code, then highly parallel reactions, like hybridization of millions of samples at once, become possible. The hexanary emitter Y1-x[DyaErbEucHodSmeTmf]xVO4, which has six narrow emission peaks in the 450-700nm range, displays millions of unique optical signatures based on the relative integrated intensities of the six emitters when the YVO4 host is excited at 325nm (He-Cd laser). The statistical analysis of a large number of samples showed that approximately 2 x 10(9) unique optical codes could be resolved, because one of the six emitters is """"""""sacrificed"""""""" as an internal standard allowing very accurate and precise ratiometric measurements to be performed. Experiments have shown that cy3-labeled DNA could be firmly attached to either encoded Controlled Pore Glass (CPG) or pure YVO4 and the signals from the organic hybridization dye reporters and the inorganic optical code can be read independently from one another within a single particle. The Phase II effort will produce the optically encoded materials in a new super high throughput bead fabrication method based on thermal wax transfer printing where it is estimated that 5-50 million encoded particles per hour can be produced. After appropriate derivitization and attachment of DNA or proteins to the beads, a variety of hybridization and protein binding experiments will be performed en masse in a flask. Subsequent decoding using Parallel's hyperspectral imaging system, after placement of the encoded particles onto a special substrate which prevents overlap of the particles, will produce a visible emission spectrum from each pixel in the acquired image providing a very high throughput means of spatially measuring the multicolor emission. The accuracy, throughput and cost estimated for this technology indicate that it could be very competitive with the current high density chip-based assays for genotyping and gene expression. ? The technology under development will allow a unique optical code to be attached to biomolecules thereby allowing them to be analyzed millions at time. The accurate optical analysis of very large numbers of small samples in parallel will reduce the cost, and increase the number of samples that can be examined, for many types of medical samples. ? ? ?
| Zhang, Fan; Haushalter, Robert C; Haushalter, Robert W et al. (2011) Rare-earth upconverting nanobarcodes for multiplexed biological detection. Small 7:1972-6 |
