Yoo, Jounghyun Kim, Youngsun Back, Ji Hyun Shin, Jawon Bae, Pan Kee Park, Kyung Mi Kim, Myung Seo, Young Hun Bak, Yecheol Heo, Yoon Ho Heo, Jeongyun Choi, Honghwan Kim, Yongju Lee, Sangyoup Lee, Ji Eun Jeong, Sohdam Yang, Jin-Kyoung Kim, Sehoon 2025-05-11T07:00:08Z 2025-05-11T07:00:08Z 2025-05-07 2025-08 0956-5663 https://pubs.kist.re.kr/handle/201004/152420 Regulating protein interactions and protein corona formation of nanomaterials is crucial for advancing nano-medicine, where surface engineering of nanomaterials plays a pivotal role in precise control over biological interactions. Here, we present a surface-engineered nanoparticle-based immunoassay platform using carboxyl-enriched polystyrene nanobeads (CEPS) with regioselectively controlled antibody-binding properties. Proteomic analysis and theoretical simulation revealed that CEPS has an enhanced Fc-specific binding affinity for immunoglobulins compared to conventional carboxylated polystyrene beads, with a higher surface carboxyl density critically mediating protein interactions. This regioselective antibody binding with unique Fc-specific affinity eliminates the need for complex surface modifications, streamlining the assay process and broadening the applicability across various immunoassay formats. Additionally, incorporating a palladium catalyst within CEPS enables solvent-triggered on-demand catalytic signal amplification using a leucodye substrate, providing a more stable alternative to enzyme-based methods while significantly enhancing detection sensitivity and stability. The platform demonstrated enhanced performance in detecting clinically relevant biomarkers, including C-reactive protein, interferon-gamma, and the receptor-binding domain of SARS-CoV2, achieving lower detection limits and faster response times compared to conventional enzyme-based ELISA systems. Notably, the CEPS-based assay retained catalytic activity for over 140 days at room temperature, underscoring its potential for reliable, long-term use in diverse diagnostic applications. English Pergamon Press Ltd. Surface-engineered nanobeads for regioselective antibody binding: A robust immunoassay platform leveraging catalytic signal amplification Article 10.1016/j.bios.2025.117463 1 Biosensors and Bioelectronics, v.281 Biosensors and Bioelectronics 281 Y scie scopus 001471540500001 2-s2.0-105002333461 Biophysics Biotechnology & Applied Microbiology Chemistry, Analytical Electrochemistry Nanoscience & Nanotechnology Biophysics Biotechnology & Applied Microbiology Chemistry Electrochemistry Science & Technology - Other Topics Article PROTEIN CORONA ULTRASENSITIVE DETECTION PALLADIUM CATALYST DRUG-DELIVERY ADSORPTION PARTICLES ASSAY IGG NANOPARTICLES FUNCTIONALIZED POLYSTYRENE immunoassay Carboxyl-enriched polystyrene nanobead Palladium catalyst Regioselective antibody binding