Point-of-care diagnosis of pre-eclampsia based on microfiber Bragg grating biosensor

Pre-eclampsia is a serious multi-organ complication that severely threatens the safety of pregnant women and infants. To accurate and timely diagnose pre-eclampsia, point-of-care (POC) biosensing of the specific biomarkers is urgently required. However, one of the key biomarkers of pre-eclampsia, placental growth factor (PlGF), has a reduced level of expression in patients, which challenges the quantification capability and Limit-of-detection (LOD) of biosensors. Herein, we reported a microfiber Bragg grating biosensor for the quantification of PlGF in clinical serum samples. The Bragg grating was inscribed in a unilateral tapered fiber to generate the segmented Fabry-Perot spectrum for improving the capability of detection. Furthermore, a temperature-calibrated Bragg grating was added to enable dual parametric detection of PlGF and temperature simultaneously for removing the crosstalk. Finally, the biosensor was envisaged to be perfectly compatible with microfluidic chips, and thus dramatically reducing the sample consumption to as small as 10 μL. The proposed biosensor can respond to PlGF with concentrations ranging from 5 to 120 pg mL^-1, attaining a LOD of 5 pg mL^-1 of clinical relevance. More importantly, the biosensor achieved micro volume detection of clinical serum samples from patients, and the ROC curve with an AUC of 0.977 confirmed the viability of the device. Our study paves the way to a new idea for cost-effective and high-precision screening of patients with pre-eclampsia, and hence envisages a promising prospect for point-of-care (POC) diagnosis of patients with pre-eclampsia.