Tungtrakarnkul P.Kumar R.K.R.Bharti A.M.Lawaniya S.D.Hu W.C.Chuang C.H.Huang S.F.Wu K.C.W.Lertanantawong B.Mahidol University2026-04-292026-04-292026-06-01Chemical Engineering Journal Vol.537 (2026)13858947https://repository.li.mahidol.ac.th/handle/123456789/116392The commercialization of affinity-based electrochemical point-of-care devices remain constrained by their reliance on external redox mediators and the longstanding challenge of simultaneously achieving high signal sensitivity and antifouling capability. Herein, we report a hierarchical nanocomposite-based all-in-one electrode coating that strategically integrates intrinsic redox activity, antifouling capability, and high conductivity into a unified, drop-castable interface. The nanocomposite comprises of redox-active ferrocene-functionalized Ce-UiO-66-NH₂ metal-organic framework (Ce-MOF-Fc) and highly conductive polyaniline nanowires (PANI NWs) embedded within glutaraldehyde-crosslinked bovine serum albumin (GB) matrix. The GB matrix suppresses nonspecific adsorption and retains 84% signal after extended exposure to fouling biofluids. Its recessed, open-pore morphology and percolated PANI NWs network enable efficient charge transport and amplifies the intrinsic redox signal of Ce-MOF-Fc. Furthermore, the nanocomposite supports facile covalent immobilization of amine-terminated biorecognition elements (e.g., aptamers, antibodies) via 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride/N-hydroxy succinimide (EDC/NHS) activation of bovine serum albumin (BSA) carboxyl groups. As a proof-of-concept, an epithelial cell adhesion molecule (EpCAM)-specific aptamer (Apt-NH₂) was designed and immobilized for label-free detection of M D Anderson-Metastatic Breast −231 (MDA-MB-231) breast cancer cells. The biosensor exhibited linearity from 5 to 800 cells/mL, a detection limit of 5 cells/mL, high reproducibility, and excellent specificity in simulated serum and urine. This modular and versatile platform offers a valuable blueprint for next-generation electrochemical affinity biosensors with broad applicability in real-world biomedical diagnostics.Chemical EngineeringChemistryEnvironmental ScienceEngineeringArticleSCOPUS10.1016/j.cej.2026.1759862-s2.0-105036050831