Engineered Nanoparticles for μPAD Nucleic Acid Detection.

Point-of-care (POC) diagnostics can provide early disease detection and continued monitoring for millions of people, domestically and internationally, who do not have access to essential support services. POC diagnostics can improve care and treatment decisions by shortening the time from analysis to diagnosis. Current POC diagnostic systems are limited by the availability of analyte options, nonspecific responses, the need for trained personnel, specialized instrumentation, and expensive biological components. Herein is presented a novel approach to develop POC diagnostics based on iron oxide@gold, core@shell, nanoparticles (Fe3O4@Au's). The particles were engineered to release signaling compounds in the presence of the target analytes and built on a paper-based microfluidic (μPAD) platform to allow for inexpensive production and high portability. As a proof-of-concept, an assay for the oligonucleotide target sequence of survivin was developed. The nanoparticles were designed to release a signal in the presence of survivin DNA, which was quantified via a fluorescence signal on the μPAD platforms. The system showed selective response for the targeted survivin sequence, and detection was achieved with buffer, artificial saliva, artificial urine, and human serum matrices.