Functional Bioimaging Probes: Fluorescent Conjugated Polymer Nanoparticles Coupled with Pleural Fluid-Derived Peptides and Proteins.

Thiol-functionalized conjugated polymers offer a versatile platform for designing fluorescent nanomaterials with biomedical relevance. In this study, a thiol modified conjugated polymer composed of benzoxadiazole (BO) and carbazole (POxC-SH) was synthesized, then converted into fluorescent nanoparticles (POxC-SH NPs) via a reprecipitation method. The nanoparticles exhibited strong photoluminescence, colloidal stability, and monodispersity in media. Surface thiol groups enabled conjugation with peptide and protein components isolated from the pleural fluid of lung adenocarcinoma patients using SMCC cross-linking. The resulting bioconjugated nanoprobe was characterized by spectroscopic methods, FTIR, XPS, and Mass spectrometry. Cellular studies in A549 and BEAS-2B cell lines demonstrated efficient internalization and low toxicity of both native and conjugated nanoparticles. This work presents a proof of concept for using thiol-modified conjugated polymer nanoparticles as intrinsically fluorescent, patient-adaptable imaging agents, bridging conjugated polymer chemistry with targeted biomedical applications.