Single-probe Pd-modified ZnO-polymer fluorescent sensor array for discrimination of thymidine analogues in aqueous media.

Thymidine analogues are widely used as antiviral and anticancer agents; however, improper dosage and prolonged exposure can lead to severe hematological and genetic complications, necessitating reliable methods for their detection and discrimination. We report an array-based fluorescence sensing platform for the discrimination of structurally related thymidine analogues in aqueous media using a Pd-modified ZnO-polymer nanocomposite as a single cross-reactive probe. The nanocomposite was synthesized by functionalizing ZnO nanoparticles with a KG3 polymer matrix followed by palladium ion modification, and its structure and morphology were confirmed using standard spectroscopic and microscopic techniques. Distinct fluorescence response patterns were generated upon interaction with different thymidine analogues, enabling their effective differentiation through multivariate statistical analysis. Principal component analysis (PCA), linear discriminant analysis (LDA), hierarchical clustering analysis (HCA), and support vector machine (SVM) classification demonstrated reliable discrimination with high accuracy across the analyte set. The sensor array exhibited sensitive fluorescence responses with limits of detection in the range of 6-100 μM. This approach demonstrates the potential of single-probe fluorescence sensor arrays combined with pattern-recognition algorithms for the discrimination of closely related nucleoside analogues in complex chemical environments.