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Persistent disparities exist in access to state‐of‐the‐art healthcare disproportionately affecting underserved and vulnerable populations. Advances in wearable sensors enabled by additive manufacturing (AM) offer new opportunities to address such disparities and enhance equitable access advanced diagnostic technologies. Additive manufacturing provides a pathway to rapidly prototype bespoke, multifunctional wearable sensors thereby circumventing existing barriers to innovation for resource‐limited settings imposed by the need for specialized facilities, technical expertise, and capital‐intensive processes. This review examines recent progress in the additive manufacture of wearable platforms for physiological health monitoring. Supported by an initial overview of relevant techniques, representative examples of 3D printed wearable sensors highlight the potential for measuring clinically‐relevant biophysical and biochemical signals of interest. The review concludes with a discussion of the promise and utility of additive manufacturing for wearable sensors, emphasizing opportunities for expanding access to vital healthcare technology and addressing critical health disparities.

 

At the intersection of the outwardly disparate fields of nanoparticle science and three-dimensional printing lies the promise of revolutionary new “nanocomposite” materials. Emergent phenomena deriving from the nanoscale constituents pave the way for a new class of transformative materials with encoded functionality amplified by new couplings between electrical, optical, transport, and mechanical properties. We provide an overview of key scientific advances that empower the development of such materials: nanoparticle synthesis and assembly, multiscale assembly and patterning, and mechanical characterization to assess stability. The focus is on recent illustrations of approaches that bridge these fields, facilitate the design of ordered nanocomposites, and offer clear pathways to device integration. We conclude by highlighting the remaining scientific challenges, including the critical need for assembly-compatible particle–fluid systems that ultimately yield mechanically robust materials. The role of domain boundaries and/or defects emerges as an important open question to address, with recent advances in fabrication setting the stage for future work in this area. 

Developing mechanically flexible composite materials with high electrical conductivity is currently hindered by the need to use high loading of conductive filler, which severely limits flexibility. Here, acoustic focusing is used to control arrangement of conductive particles in photopolymer matrices to create composites with both tunable conductivity and flexibility. Acoustophoresis patterns filler particles into highly efficient percolated networks which utilize up to 97% of the particles in the composite, whereas the inefficient stochastic networks of conventional dispersed‐fiber composites utilize<5%. These patterned materials have conductivity an order of magnitude higher than conventional composites made with the same ink, reaching 48% the conductivity of bulk silver within the assembled silver‐particle networks (at 2.6 vol% loading). They also have low particle loading so that they are flexible, withstanding>500 bending cycles without losses in conductivity and changing conductivity only 5% within cycles on average. In contrast, conventional unpatterned composites with the same conductivity require such high loading that they are prohibitively brittle. Finally, modulating the applied acoustic field controls the anisotropy of the conductive networks and produces materials which are either 2D conductive, 1D conductive, or insulating, using the same nozzle and ink, paving the way for versatile multifunctional 3D printing.