Atmospheric Cold Plasma Technology Enabling Scalable Surface‐Independent Protein Immobilization for Biosensing Applications

Abstract Biosensors show great potential across various fields including, but not limited to, medical diagnostics, drug development, and environmental monitoring. Yet, commercialization faces challenges, particularly in fabrication and biofunctionalization, due to specific surface properties needed for each application. This highlights the need for a standardized biomolecule immobilization process, enabling straightforward target detection on various surfaces. Cold atmospheric plasma technology offers a scalable solution, combining surface activation with molecule grafting in a single step. This technology is employed to construct stable surface‐independent carboxylic acid (COOH) linker‐layer coatings, enabling covalent protein immobilization via 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) chemistry and creating a robust biointerface for bioassay integration. The coating's composition, surface energy, thickness, topography, and stability confirm a secure COOH‐rich layer. Biofunctionalization is studied in depth by immobilizing immunoglobulin G (IgG), streptavidin, and protein G. Enzyme‐linked immunosorbent assay (ELISA)‐based model bioassays demonstrate protein‐independent functionalization and linker‐layer stability of at least one month (stored in air). The calibration curve for IgG‐biotin detection shows a high signal‐to‐noise ratio. Consistent performance across polymethylmethacrylate (PMMA), cyclic olefin copolymer (COC), polyvinyl chloride (PVC), and glass proves the method’s universal applicability. Hence, this technology enables versatile, scalable, cost‐effective biosensor fabrication with high‐performance bioreceptor layers on various surfaces.