Yolk-shell composite optical sensors with chiral L-histidine/Rhodamine 6G for high-sensitivity turn-on detection of L-proline

Chirality is a ubiquitous phenomenon in nature and has attracted wide attention in the biomedicine, pharma-ceutics and biosensing research fields. Enantiomeric recognition of chiral compounds, especially chiral drugs and chiral amino acids, is important for human health and nutrition. In this work, through the encapsulation of L-His&R6G (L-His =L-Histidine; R6G = Rhodamine 6G) into MOF@MOF framework ZIF-67@ZIF-8, composited material L-His&R6G@ZIF-67@ZIF-8 can be obtained. Additionally, through the etching process, a unique yolk-shell ZIF-8 chiral composite optical sensors L-His&R6G@ZIF-8 (1) can be successfully prepared. Photo -luminescent (PL) experiment also reveals that 1 can highly sensitively detect L-Proline (L-Pro) through the turn-on detection strategy (KBH = 1.22 x 104 M-1 and detection limit 1.9 mu M). Further yolk-shell L-His&R6G@ZIF-8-based fabricate flexible mixed-matrix membranes has been prepared using doctor-blading technique, which show significant fluorescence enhancement effect under ultraviolet lamp. This work also provides the unique example of preparing chiral yolk-shell framework composite sensors, which have broad application in chiral sensing area.

Automated summary

In this study, a unique chiral composite optical sensor was successfully prepared through encapsulation and etching methods, which can highly sensitively detect chiral amino acids. Additionally, a flexible mixed-matrix membrane based on this chiral composite sensor was prepared, showing significant fluorescence enhancement effect.