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.

Nanoparticles can be assembled in space using additive printing to create complex hierarchical 3D microarchitected and nanoarchitected materials.

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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.

Microelectrode arrays (MEAs) provide the means to record electrophysiological activity fundamental to both basic and clinical neuroscience (e.g. brain-computer interfaces). Despite recent advances, current MEAs have significant limitations -including recording density, fragility, expense, and the inability to optimize the probe to individualized study or patient needs.Here we address the technological limitations through the utilization of the newest developments in 3D nanoparticle printing. 1 Our 'CMU Arrays' possess previously impossible electrode densities (> 6000 channels/cm 2 ) with tip diameters as small as 10µm. Most importantly, the probes are entirely customizable owing to the adaptive manufacturing process. Any combination of individual shank lengths, impedances, and layouts are possible. This is achieved in part via our new multi-layer, multi material, custom 3D-printed circuit boards, a fabrication advancement in itself. This device design enables new experimental avenues of targeted, large-scale recording of electrical signals from a variety of biological tissues.

In article number 2006647, Rahul Panat and co‐workers report the development of a 10‐second COVID‐19 antibody test that represents the fastest detection of this pathogen biomarker. The test uses an electrochemical cell consisting of aerosol jet nanoprinted 3D micropillar electrodes coated with reduced graphene oxide and viral antigens. This generic platform could be a game‐changer in controlling the spread of infectious diseases during pandemics.

Microelectrode arrays provide the means to record electrophysiological activity critical to brain research. Despite its fundamental role, there are no means to customize electrode layouts to address specific experimental or clinical needs. Moreover, current electrodes demonstrate substantial limitations in coverage, fragility, and expense. Using a 3D nanoparticle printing approach that overcomes these limitations, we demonstrate the first in vivo recordings from electrodes that make use of the flexibility of the 3D printing process. The customizable and physically robust 3D multi-electrode devices feature high electrode densities (2600 channels/cm 2 of footprint) with minimal gross tissue damage and excellent signal-to-noise ratio. This fabrication methodology also allows flexible reconfiguration consisting of different individual shank lengths and layouts, with low overall channel impedances. This is achieved, in part, via custom 3D printed multilayer circuit boards, a fabrication advancement itself that can support several biomedical device possibilities. This effective device design enables both targeted and large-scale recording of electrical signals throughout the brain.

Rapid detection of antibodies to SARS-CoV-2 is critical for COVID-19 diagnostics, epidemiological research, and studies related to vaccine evaluation. It is known that the nucleocapsid (N) is the most abundant protein of SARS-CoV-2 and can serve as an excellent biomarker due to its strong immunogenicity. This paper reports a rapid and ultrasensitive 3D biosensor for quantification of COVID-19 antibodies in seconds via electrochemical transduction. This sensor consists of an array of threedimensional micro-length-scale electrode architecture that is fabricated by aerosol jet 3D printing, which is an additive manufacturing technique. The micropillar array is coated with N proteins via an intermediate layer of nano-graphene and is integrated into a microfluidic channel to complete an electrochemical cell that uses antibodyantigen interaction to detect the antibodies to the N protein. Due to the structural innovation in the electrode geometry, the sensing is achieved in seconds, and the sensor shows an excellent limit of detection of 13 fm and an optimal detection range of 100 fm to 1 nM. Furthermore, the sensor can be regenerated at least 10 times, which reduces the cost per test. This work provides a powerful platform for rapid screening of antibodies to SARS-CoV-2 after infection or vaccination.