Highly Stable Bio-templated InP/ZnSe/ZnS Quantum Dots for Specific Monitoring of Bacterial Membrane Proteins

Despite their unique optical and electrical characteristics, traditional semiconductor quantum dots (QDs) made of heavy metals or carbon are not compatible with many biomedical applications. Cytotoxicity and environmental concerns are key limiting factors that prevent their widescale transition from laboratory research to real-world medical applications. Recently, advanced InP/ZnSe/ZnS QDs have emerged as excellent alternatives to traditional QDs due to their lower toxicity and optical properties; however, they fall short of traditional QDs with respect to their versatility for bioconjugation (i.e., surface chemistry limitations causing unstability in aqueous environments). In this work, we construct a road map for generating, for the first time, highly efficient bio-templated InP/ZnSe/ZnS-aptamers (QDAPT) with long-term stability and high selectivity for applications in targetting bacterial membrane proteins. Our QDAPTs show fast binding reaction kinetics (less than 5 minutes), high brightness, and high shelf-life stability (3 months) after biotemplation in aqueous solvents. We also demonstrate the detection of bacterial membrane proteins on common surfaces using a hand-held imaging device, which attests to the great potential of this system for incorporation into future biomedical technologies.