Development of semiconductor nanomaterial whole cell imaging sensor on glass slides

We report the development of a highly specific semiconductor quantum dots (QDs)-based whole cell imaging sensor that offer rapid, reproducible, accurate, and long term cell imaging system on silanized microscope glass slides. The QD-based imaging sensor involved capture of whole cells with QD labeled highly specific antibodies against over expressed cell membrane proteins. The QDs were first modified with a polymer coating to generate carboxyl groups on the surface. Using the carboxylated QDs, antibodies were covalent conjugated using carbodiimide chemistry to form 2(0)Ab~QD that were used to capture whole cell. The SK-BR3 cell line was used as a model analyte in the sandwich type assay consisting of 1(0)Ab + SK-BR3 + Ab' + 2(0)Ab~QD. The assay was immobilized on an antibody modified silanized microscope slide that was subsequently mounted on a fluorescence microscope for detection. The results indicated that the QD based imaging sensor exhibited brighter signals compared with organic dye Texas red. The QD-based whole cell imaging sensor was visible under the microscope even after one week without fixation.