Fabrication of CdSe/ZnS Quantum-Dot-Conjugated Protein Microarrays and Nanoarrays

Abstract

We demonstrate the fabrication and the detection of protein microarrays and nanoarrays, which are tagged by using colloidal CdSe/ZnS quantum dots (QDs), for the purpose of optical readout of those biochips. A microarrayer and a dip-pen nanolithography technique were used for the fabrication of QD-labeled protein microarrays and nanoarrays, respectively. The optical readout of those biochips was conducted by using a microchip scanner and a confocal scanning microscope in the case of the microarrays while an atomic force microscope was employed for characterizing the nanoarrays. We also report a possible way of reducing the 'doughnut phenomenon' in microarrays by varying the spot size from 300 mu m to 100 mu m, wherein the fluorescence intensity distribution becomes more uniform with decreasing spot diameter.