Advanced molecular recognition of 3-nitro-L-tyrosine: The use of zwitterion embedded molecularly imprinted mesoporous organosilica with sub-nanomolar sensitivity.

Fabricating a state-of-the-art system capable of probing any chosen target molecule with a high degree of selectivity is the foremost objective of molecular recognition materials. In this paper, we developed a versatile target-probe utilizing zwitterion embedded molecularly imprinted mesoporous organosilica to fill the gap in our current capabilities. Graphene quantum dots were encapsulated as a signal transducer to prepare the fluorescent probe (NTIMO-zQ), and the concentration-dependent emission change was analyzed by adding 3-nitro-L-tyrosine (NT). The NTIMO-zQ showed an unprecedented degree of fluorescence quenching which also exhibited a sub-nanomolar sensitivity for NT; proving itself to be the most sensitive NT probe reported to date. By investigating the sigmoidal fitting of this quenching behavior, the selectivity performance can be quantitatively analyzed; and the resulting measurements are taken to determine the effective concentration (EC50) values with respect to NT. The NTIMO-zQ probe presents an extremely low EC50 with NT (9.7 nM) compared to several other NT analogues. The probe we have developed is both reproducible and repeatable with a satisfactory recovery rate (97-102%), and moreover, it exhibits suitably low detection limit (0.0129 nM).