Developing point-of-care (PoC) diagnostic platforms for carcinoembryonic antigen detection is essential. However, thefew implementations of transferring the signal amplification strategies in electrochemical sensing on paper-based platforms are not satisfactory in terms of detection limit (LOD). In the quest for pushing down LOD, majority of the research has been targeted towards development of improved nanostructured substrates for entrapping more analyte molecules and augmenting the electron transfer rate to the working electrode. But, such approaches have reached saturation. This paper focuses on enhancing the mass transport of the analyte towards the sensor surface through the application of an electric field, in graphene-ZnO nanorods heterostructure. These hybrid nanostructures have been deposited on flexible polyethylene terephthalate substrates with screen printed electrodes for PoC application. The ZnO nanorods have been functionalized with aptamers and the working sensor has been integrated with smartphone interfaced indigenously developed low cost potentiostat. The performance of the system, requiring only 50 µl analyte has been evaluated using electrochemical impedance spectroscopy and validated against commercially available ELISA kit. Limit of detection of 1 fg/ml in human serum with 6.5% coefficient of variation has been demonstrated, which is more than three orders of magnitude lower than the existing attempts on PoC device.

This paper provides a concise yet comprehensive review of spatial environment sensing and perception in automated systems, crucial for intelligent applications such as smart cities, smart homes, navigation, automated driving and industry 4.0. With a focus on achieving dependable performance even in harsh environments and enabling affordable mass deployment, the review explores sensor technologies, calibration, diagnostics, performance degradation analysis, and machine-learning-based perception algorithms. Our contributions aim to deepen understanding and drive progress in automated systems, addressing challenges across diverse application scenarios. Through a meticulous analysis of the pros and cons of state-of-the-art technologies, the paper sheds light on future trends in research and development. This work serves as a valuable resource for researchers, practitioners, and industry professionals seeking insights into the evolving landscape of spatial environment sensing and perception.