Functional Integration of Magnetic Enrichment and Plasmonic Enhancement on a Gold Nanowire Film for Ultrasensitive SERS Immunosensing of CK-MB

State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 211189, China

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Abstract

The early and accurate diagnosis of acute myocardial infarction (AMI) depends on the sensitive detection of the cardiac biomarker Creatine Kinase MB isoenzyme (CK-MB). However, conventional immunoassays still suffer from limited sensitivity and speed for practical point-of-care testing.Herein, we report a novel surface-enhanced Raman scattering (SERS) immunosensing platform based on the functional integration of pre-synthesized nanomaterials. The key innovation lies in a “sandwich-on-substrate” architecture, in which the classic sandwich immunocomplex is concentrated and immobilized onto a flexible, jellyfish-like gold nanowire (AuNW) film.This design enables strong plasmonic coupling between the AuNW substrate and SERS-active Ag–Au core–shell nanoflower (BCSNF) tags, providing more than one order-of-magnitude signal enhancement over conventional formats.The integrated platform exhibits excellent analytical performance toward CK-MB detection, with a wide linear range, a high correlation coefficient (R² = 0.990), and a low detection limit of 0.076 ng/mL.This work demonstrates that rational integration of high-performance nanomaterials—rather than complex de novo synthesis—represents a reliable and efficient strategy for constructing advanced biosensors, paving the way for the development of next-generation ultrasensitive point-of-care diagnostic devices.