Highly stable and luminescent ZIF-8@MAPbBr3 enhanced “turn on” fluorescent aptasensor for azlocillin monitoring

As emerging luminescent materials, perovskite quantum dots (PQDs) have attracted considerable attention due to their exceptional fluorescence properties. However, their practical application is hindered by inherent instability and high toxicity. In this study, we developed a “turn-on” fluorescent aptasensor for azlocillin detection by integrating aptamer A58-modified ZIF-8-encapsulated MAPbBr 3 (ZIF-8@MAPbBr 3 @A58) with complementary DNA-functionalized magnetic beads (MBs@cDNA). We first rationally designed a 2-aminobenzimidazole and Mn 2+ co-doped ZIF-8@MAPbBr 3 composite, exhibiting enhanced stability, strong luminescence, low biotoxicity and facile modification. The ZIF-8@MAPbBr 3 was further functionalized with A58 to serve as a highly specific signal probe (ZIF-8@MAPbBr 3 @A58), while MBs@cDNA acted as a magnetic separation probe. In the present of azlocillin, the ZIF-8@MAPbBr 3 @A58 probe displayed high affinity toward the targe, leading to the dissociation of the ZIF-8@MAPbBr 3 @A58-MBs@cDNA complex and resulting in enhanced fluorescence intensity. Subsequently, the complementary region between aptamer and cDNA was optimized guided by the molecular docking. Under optimal conditions, the proposed aptasensor achieved a limit of detection of 0.014 ng/mL, with a linear range of 0.1-100 ng/mL. This work demonstrates that ZIF-8 encapsulation combined with ion doping effectively addresses PQD instability. And the strategy paves the way for developing stable PQD-based aptasensors for trace antibiotic monitoring.