An intelligent portable point-of-care testing (POCT) device for on-site quantitative detection of TNT explosive in environmental samples

The detection of explosives is crucial for ensuring homeland security and safeguarding public health and safety. To enhance the monitoring and management of explosives contaminants, especially in resource-poor environments, there is an urgent need for portable, accurate and intelligent quantitative point-of-care testing (POCT) platform. Here, we have achieved on-site quantitative detection for trinitrotoluene (TNT) using an intelligent portable POCT device for the first time. The portable platform integrated TNT biosensing complex, 3D-printing microfluidic chip (3D-Chip) and intelligent reading device. The key biosensing consisted of APTES-modified SiO₂ aerogels (ASA) and aptamer-coupled PtNPs (APtNPs). SiO₂ aerogel owing large specific surface area enhanced the adsorption effect and ensured the efficient capture of TNT by ASA. APtNPs acted as a specific reporter bioprobe and form sensing complex with TNT captured by the substrate. The biosensing complex converted the TNT concentration into measurable displacement on 3D-Chip by catalyzing H₂O₂. Simultaneously, intelligent reading device enabled image acquisition, analysis and output, facilitating efficient and portable detection. The device demonstrated a strong linear relationship for TNT in the range of 0.1–100 μg/mL with LOQ of 0.81 μg/mL. The whole quantitative analysis of TNT could be completed within 30 min, significantly reducing the analysis time compared to ultraviolet based method (8 h). Furthermore, on-site TNT detection in real samples showed excellent agreement with the national standard method, demonstrating exceptional accuracy. This quantitative POCT device opens up the possibility of greatly simplified explosives diagnostics in environmental pollution assessment.