Metal-Doped Boron Quantum Dots for Versatile Detection of Lactate and Fluorescence Bioimaging

To improve the stability and fluorescence (FL) of monoelemental boron nanomaterials, this work put forward a metal-coordination strategy to explore emerging metal-doped boron quantum dots, Co@BQDs. Through theoretical calculations, B–Co bonding as predicted can suppress the B–O reaction and protect the electronic structures of exfoliated two-dimensional (2D) boron from oxidation and decomposition upon exposure to oxygen. In experimental studies, Co2+ was added into a dispersion liquid of bulk boron and subjected to probe sonication to promote Co2+ adsorption on the surface of exfoliated 2D boron, followed by Co2+ coordination with exposed boron atoms. Solvothermal treatment of exfoliated 2D boron resulted in the generation of Co2+-doped 0D boron Co@BQDs. Experimental results confirm that Co@BQDs have higher colloidal and FL stability than BQDs as a reference. B–Co bonding formation to suppress the B–O reaction ensures the high stability of exfoliated boron structures. A dispersion liquid of Co@BQDs with stable and bright FL was used for visual FL imaging of solutions and solid substrates. Based on enzymatic and cascade oxidation-induced FL quenching of Co@BQDs, a novel FL bio-probe of lactate was explored. This bio-probe, with a broad detection range of 0.01–10 mM and a low detection limit of 3.1 μM, enables FL sensing of lactate in biosamples and shows high detection recoveries of 98.0–102.8%. Moreover, this bio-probe realized versatile FL imaging and visual detection of lactate in liquid/solid-phase systems. These results demonstrate great prospects of Co@BQDs as emerging and efficient imaging reagents for long-term tracking and bioimaging applications

Ratiometric and Time-Resolved Fluorimetry from Quantum Dots Featuring Drug Carriers for Real-Time Monitoring of Drug Release in Situ

An effective ratiometric and time-resolved fluorimetry was described. On the basis of Förster resonance energy transfer (FRET) between semiconductor quantum dots (QDs) and fluorescent drugs, poly­(ethylene glycol)-modified QDs were successfully prepared and further developed as QDs featuring carriers for real-time monitoring of drug release in situ