Highly\nStable Biotemplated InP/ZnSe/ZnS Quantum Dots\nfor <i>In Situ</i> Bacterial Monitoring

Despite\ntheir unique optical and electrical characteristics, traditional\nsemiconductor quantum dots (QDs) made of heavy metals or carbon are\nnot ideally suited for biomedical applications. Cytotoxicity and environmental\nconcerns are key limiting factors affecting the adoption of QDs from\nlaboratory research to real-world medical applications. Recently,\nadvanced InP/ZnSe/ZnS QDs have emerged as alternatives to traditional\nQDs due to their low toxicity and optical properties; however, bioconjugation\nhas remained a challenge due to surface chemistry limitations that\ncan lead to instability in aqueous environments. Here, we report water-soluble,\nbiotemplated InP/ZnSe/ZnS-aptamer quantum dots (QDAPTs) with long-term\nstability and high selectivity for targeting bacterial membrane proteins.\nQDAPTs show fast binding reaction kinetics (less than 5 min), high\nbrightness, and high levels of stability (3 months) after biotemplating\nin aqueous solvents. We use these materials to demonstrate the detection\nof bacterial membrane proteins on common surfaces using a hand-held\nimaging device, which attests to the potential of this system for\nbiomedical applications.