Improving the Efficiency of Luminescent Zn(II)-Modified N-Doped GOQD Nanomaterials in Parkinson's Disease Treatment: A Theoretical Mechanistic Framework Exploring Doping Effect.

Levodopa, a widely prescribed drug in Parkinson's disease treatment, stands as the foremost prodrug of dopamine. An affordable self-testing kit is utilized to monitor levodopa content in anti-parkinson drugs in human serum. A photoluminescent trinuclear Zn(II) complex [Zn3(L) ² (κ ¹ -OAc)2(κ ² -OAc) ₂ ] has been synthesized, which cleaves into mononuclear ZC in aqueous solution. ZC was found to detect L-Dopa in Tris-HCl buffer, exhibiting a moderate decrease in PL-emission. The real-life utility of the ZC probe is limited, for its lower sensitivity (LOD 35.3 μM) and separation challenges. Therefore, an interface between homogeneous and heterogeneous supports has been explored, leading to the strategic development of NGOZC, where ZC was grafted onto NGOQD (Graphene oxide quantum dots). This material enables naked- eye detection under both ambient and UV light with color change from bright cyan to green, followed by dark. The nitrogen doping effect was investigated by several comparative investigations involving the synthesis of ZC-grafted GOQD, leading to enhanced quenching performance. Steady-state and time-resolved fluorescence titration study, morphological analysis, and computational calculations have been performed to get insights into the sensing mechanism. To the best of our knowledge, this as-synthesized NGOZC (LOD 1.78 nM) represents a promising strategy and platform for applications in biosensors, especially for Parkinson's and Alzheimer's diseases.
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