Bimetallic nanoprobe strip for the detection of human chorionic gonadotrophin in pregnancy

A novel nanotechnology-based approach was developed to enhance the accuracy and reliability of pregnancy detection to address the limitations of conventional kits like PregaNews, First Response, Accu-Clear, EPT (Error Proof Test), etc. which are based on the enzyme-linked immunosorbent assay (ELISA) method. Such conventional methods often suffer from complex procedures, low precision (33 %), cross-reactivity, and false positives. The developed new diagnostic platform employed a lateral flow assay-based gold-silver nanoprobe (GSNPs) system conjugated with 3-mercaptopropionate and monoclonal antibody 2 (mAb2), pre-dispersed on biodegradable Whatman filter paper and coupled with a smartphone-based application for the detection of hCG in pregnancy. The GSNPs with a particle size of 325.1 ± 0.64 nm, exhibited superior catalytic efficiency (0.29 to 0.37 nm) with significant specificity, and reliability in comparison to digital color analysis via RGB (red, green, blue) and HSV (hue, saturation, value) algorithmic model. This nanotechnology-based system demonstrated a wide detection range (0.4-2.4ng/mL) with a low limit of detection (LOD) at 0.79 ng/mL and limit of quantification (LOQ) at 9.67 ng/mL. The detection of pathological urine was consistent with the artificial urine sample at R²=0.9796 and showed linear relationship with saturation value (y = 5.1849x+3.4559). The biodegradable and portable diagnostic strip generates minimal bio-waste and offers eco-friendly disposal. This platform tool-based strip enables sensitive, rapid, user-friendly, and cost-effective detection of hCG compared to conventional pregnancy tests. The integration of bimetallic nanoprobe strip with smartphone technology ensures ease of accessibility, high precision, and environmental sustainability to increase the demand for such reliable and economic diagnostic tool.