Highly sensitive detection of C-reactive protein in sweat via dendritic gold structure with double-antibody sandwich assay

The demand for early detection of inflammation-related diseases has driven interest in non-invasive methods like sweat analysis for their simplicity and rapid response. This paper develops a non-invasive C-reactive protein (CRP) sensor based on a three-dimensional dendritic gold structure electrode, which features high sensitivity, broad detection range, and excellent specificity. By in-situ growing dendritic gold on the gold electrode surface, the specific surface area of the sensor is 2.41 times that of the gold electrode. This increases the binding sites for CRP-capturing antibody (cAb), enabling the sensor to achieve a sensitivity of 3.26 µA mL ng −1 , which is 3.33 times that of the gold electrode. A double-antibody sandwich assay is employed using thionine-labeled spherical gold nanoparticles-antibody (AuNPs-dAb) conjugates as detection probes, with bovine serum albumin (BSA) blocking to minimize interference. The approach enhances sensor specificity and accuracy while enabling low-concentration detection, achieving a linear detection range of 0.5–30 ng mL −1 . The sensor's detection results exhibited a correlation coefficient of 0.995 with hospital-standard instruments. Additionally, a sweat-processing device and a flexible printed circuit board (FPCB) are integrated. Data are transmitted to mobile terminals via low-power near field communication (NFC). This platform facilitates early inflammation detection in clinical and home settings.