Paper is an attractive platform for the development of low cost analytical devices for the prevention and diagnosis of diseases. For diagnostic purposes in developing countries, paper technology is designed to fulfill the World Health Organization's ASSURED criteria (i.e. affordable, sensitive, specific, user-friendly, rapid and robust, equipment free and deliverable to end-users). In our group, Forster resonance energy transfer (FRET)-based assays using luminescent nanoparticles (NPs) are integrated into paper devices for detection of nucleic acids and protein biomarkers. A variety of FRET systems were developed in our group in which colloidal inorganic NPs were used either as FRET donors or acceptors, including: quantum dot (QD)-organic dye, QD-gold NP (AuNP), upconversion nanoparticle (UCNP)-organic dye, and UCNP-QDs. To develop these solid-phase assays, our group has conducted extensive research on NP synthesis, characterization and bioconjugation, as well as paper modification and strategies for immobilization of NPs on paper. The figures below, with the corresponding journal articles, depict some of the research projects being pursued by the group.
Quantum Dots in Solid Phase Nucleic Acid Diagnostics
M.O. Noor and U.J. Krull, Paper-based Solid-Phase Multiplexed Nucleic Acid Hybridization Assay With Tunable Dynamic Range Using Immobilized Quantum Dots as Donors in Fluorescence Resonance Energy Transfer, Analytical Chemistry, 85: 7502-7511, 2013 (http://pubs.acs.org/doi/abs/10.1021/ac401471n).
Detecting Biomolecules via the Development of Luminescence Resonance Energy Transfer (LRET)-Based Interfacial Bioassays on Glass and Paper Substrates
S. Doughan, U. Uddayasankar, A. Peri and U.J. Krull, A Paper-Based Multiplexed Resonance Energy Transfer Nucleic Acid Hybridization Assay Using a Single Form of Upconversion Nanoparticle as Donor and Quantum Dots as Acceptors, Analytica Chimica Acta, 962: 88-96, 2017 (http://www.sciencedirect.com/science/article/pii/S0003267017301046?via%3Dihub).
Towards Paper Based Assays Using Intrinsically Labeled Oligonucleotide Probes on QD for Determination of Selective Hybridization
A. Shahmuradyan and U.J. Krull, Intrinsically Labeled Fluorescent Oligonucleotide Probes on Quantum Dots for Transduction of Nucleic Acid Hybridization, Analytical Chemistry, 88, 6: 3186-3193, 2016 (http://pubs.acs.org/doi/abs/10.1021/acs.analchem.5b04536).