Interfacing anatomically conformal electronic components, such as sensors, with biology is central to the creation of next-generation wearable systems for health care and human augmentation applications. Thus, there is a need to establish computer-aided design and manufacturing methods for producing personalized anatomically conformal systems, such as wearable devices and human-machine interfaces (HMIs). Here, we show that a three-dimensional (3D) scanning and 3D printing process enabled the design and fabrication of a sensor-integrated anatomical human-machine interface (AHMI) in the form of personalized prosthetic hands that contain anatomically conformal electrode arrays for children affected by amniotic band syndrome, a common birth defect. A methodology for identifying optimal scanning parameters was identified based on local and global metrics of registered point cloud data quality. This method identified an optimal rotational angle step size between adjacent 3D scans. The sensitivity of the optimization process to variations in organic shape ( i . e ., geometry) was examined by testing other anatomical structures, including a foot, an ear, and a porcine kidney. We found that personalization of the prosthetic interface increased the tissue-prosthesis contact area by 408% relative to the non-personalized devices. Conformal 3D printing of carbon nanotube-based polymer inks across the personalized AHMI facilitated the integration of electronic components, specifically, conformal sensor arrays for measuring the pressure distribution across the AHMI ( i . e ., the tissue-prosthesis interface). We found that the pressure across the AHMI exhibited a non-uniform distribution and became redistributed upon activation of the prosthetic hand’s grasping action. Overall, this work shows that the integration of 3D scanning and 3D printing processes offers the ability to design and fabricate wearable systems that contain sensor-integrated AHMIs.

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Here, we show that improving the fit of a cloth mask using a low-cost 3D-printed frame significantly improves its inward protection efficiency for airborne particles known to transmit SARS-CoV-2. We found that a 3D-printed flexible frame (i.e., brace) increased the inward protection efficiency of a cottonbased cloth mask by 13−43% for particles ranging in size from 0.5−2 μm relative to the efficiency obtained in the absence of the frame. For example, the use of a flexible form-fitting frame increased the inward protection efficiency for 0.5 and 1 μm particles by 31 and 40%, respectively. Rapid prototyping of the mask frame geometry and material properties was also highlighted for optimization of the facial contact area and mechanical matching. This work demonstrates the opportunity for leveraging additive manufacturing processes for rapid prototyping of personalized and form-fitting personal protective equipment components at home and at point-of-care settings, such as mask frames.

We report a reverse engineering-driven method for conformal microextrusion three-dimensional (3D) printing of functional materials on complex 3D structures and thin films of near-arbitrary topography. A non-planar tool path programming algorithm for conformal microextrusion 3D printing based on point cloud data representations of object geometry is presented. We show that the optimal nozzle-substrate standoff distance for quality 3D printing depends on the substrate's local geometric features (i.e. slope and curvature) and the tool trajectory. The impact and utility of the novel conformal microextrusion 3D printing process were demonstrated by fabrication of 3D spiral and Hilbert-curve loop antennas on various non-planar substrates, including wrinkled and folded Kapton films and origami. 3D-printed conformal antennas exhibited resonant frequencies ranging from 1.5 to 2.7 GHz with S 11 less than 10 db. This work provides a new method for conformal 3D printing on one-of-a-kind objects and non-planar films.

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