Rapid diagnosis is critical for the treatment and prevention of diseases. An advanced nanomaterial‐based biosensing platform that detects COVID‐19 antibodies within seconds is reported. The biosensing platform is created by 3D nanoprinting of three‐dimensional electrodes, coating the electrodes by nanoflakes of reduced‐graphene‐oxide (rGO), and immobilizing specific viral antigens on the rGO nanoflakes. The electrode is then integrated with a microfluidic device and used in a standard electrochemical cell. When antibodies are introduced on the electrode surface, they selectively bind with the antigens, changing the impedance of the electrical circuit which is detected via impedance spectroscopy. Antibodies to SARS‐CoV‐2 spike S1 protein and its receptor‐binding‐domain (RBD) are detected at a limit‐of‐detection of 2.8 × 10−15 and 16.9 × 10−15 m, respectively, and read by a smartphone‐based user interface. The sensor can be regenerated within a minute by introducing a low‐pH chemistry that elutes the antibodies from the antigens, allowing successive sensing of test samples using the same sensor. Sensing of S1 and RBD antibodies is specific, which cross‐reacts neither with other antibodies such as RBD, S1, and nucleocapsid antibody nor with proteins such as interleukin‐6. The proposed sensing platform could also be useful to detect biomarkers for other infectious agents such as Ebola, HIV, and Zika.

Sensing of clinically relevant biomolecules such as neurotransmitters at low concentrations can enable an early detection and treatment of a range of diseases. Several nanostructures are being explored by researchers to detect biomolecules at sensitivities beyond the picomolar range. It is recognized, however, that nanostructuring of surfaces alone is not sufficient to enhance sensor sensitivities down to the femtomolar level. In this paper, we break this barrier/limit by introducing a sensing platform that uses a multi-length-scale electrode architecture consisting of 3D printed silver micropillars decorated with graphene nanoflakes and use it to demonstrate the detection of dopamine at a limit-of-detection of 500 attomoles. The graphene provides a high surface area at nanoscale, while micropillar array accelerates the interaction of diffusing analyte molecules with the electrode at low concentrations. The hierarchical electrode architecture introduced in this work opens the possibility of detecting biomolecules at ultralow concentrations.

Soil monitoring is emerging as a key factor to manage smart farming which has been recommended to have economical food safety and security. Among various development for example internet of things assisted farming, electrochemical sensing system are getting popularity via detecting one or multiple soil component effectively, efficiently, and selectively for soil quality assessment remotely via data sharing and site of location just like point-of-care soil heath care. Considering scenarios, this perspective is designed to describe state-of-the art electrochemical sensing technology developed for soil quality. The associated challenges, possible alternatives, and potential prospects are also discussed in this perspective.

Additive manufacturing, also called 3D printing, is a rapidly evolving technique that allows for the fabrication of functional materials with complex architectures, controlled microstructures, and material combinations. This capability has influenced the field of biomedical sensing devices by enabling the trends of device miniaturization, customization, and elasticity (i.e., having mechanical properties that match with the biological tissue). In this paper, the current state‐of‐the‐art knowledge of biomedical sensors with the unique and unusual properties enabled by 3D printing is reviewed. The review encompasses clinically important areas involving the quantification of biomarkers (neurotransmitters, metabolites, and proteins), soft and implantable sensors, microfluidic biosensors, and wearable haptic sensors. In addition, the rapid sensing of pathogens and pathogen biomarkers enabled by 3D printing, an area of significant interest considering the recent worldwide pandemic caused by the novel coronavirus, is also discussed. It is also described how 3D printing enables critical sensor advantages including lower limit‐of‐detection, sensitivity, greater sensing range, and the ability for point‐of‐care diagnostics. Further, manufacturing itself benefits from 3D printing via rapid prototyping, improved resolution, and lower cost. This review provides researchers in academia and industry a comprehensive summary of the novel possibilities opened by the progress in 3D printing technology for a variety of biomedical applications.