Paper Lateral Flow Strips Based on Gold Nanorods for Ultrasensitive Detection of Traumatic Brain Injury Biomarkers

Biofluid biomarkers, as objective predictors of traumatic brain injury (TBI) pathobiological processes, play an important role in the early detection of TBI. However, the lack of sensitive and rapid detection assays to detect biomarker levels has been an urgent problem. In this study, we devised a novel surface-enhanced Raman scattering (SERS)-based paper lateral flow strip (PLFS) based on gold nanorods (AuNRs) with controlled aspect ratios for the screening and diagnosis of TBI. To improve the sensitivity of the designed device, AuNRs, as the key component of SERS probes, were optimized by controlling the particle morphology, showing great local plasma enhancement. Furthermore, using thionin acetate (THI) as a Raman reporter, the detection performance of PLFS was further improved due to the unique molecular structure of THI. Thus, the constructed PLFS has been demonstrated to be ultrasensitive, with a limit of detection (LOD) reaching ∼10–1 pg·mL–1. Fo r real-world measurements of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) in blood samples, the results monitored by the SERS assay were exactly consistent with those obtained through the traditional enzyme-linked immunosorbent assay (ELISA). The above result demonstrated that the developed SERS-PFLS has extensive application prospects in the screening and diagnosis of TBI in the emergency department as point-of-care testing (POCT) and may further shift the paradigm of TBI patient management and clinical outcome in emergency departments.