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Abstract: Waste energy harvest using thermoelectric (TE) materials will be a potential solution to the serious environmental pollution and energy shortage problems. Due to limitations of current manufacturing techniques in geometry complexity and high density, TE devices are not widely utilized in daily life to gather waste energy. 3D printing brings an opportunity to solve the fabrication limitations. In this paper, a hybrid process was developed to fabricate thermoelectric materials by integrating hot pressing with stereolithography. The mold and punch were designed and printed to fabricate thermoelectric devices used on hot water tubes via stereolithography. The Sb2Te3 powders filled the 3D printed mold in a layered manner, and each layer of powders was compacted under the pressing of punch at a certain temperature and compressive force. The polymer mold was removed after the sintering process to form the final TE components. A series of experiments were conducted to identify the optimal heating temperature and compressive force. The microstructures morphology and electrical conductivity of fabricated Sb2Te3 samples were evaluated. This research work conducted a scientific investigation into the fabrication of TE material with a hybrid process, including hot pressing and 3D printing, to solve the current manufacturing challenges, providing perspectives on developments of TE devices used in various energy harvest applications. 

Abstract Microneedle arrays show many advantages in drug delivery applications due to their convenience and reduced risk of infection. Compared to other microscale manufacturing methods, 3D printing easily overcomes challenges in the fabrication of microneedles with complex geometric shapes and multifunctional performance. However, due to material characteristics and limitations on printing capability, there are still bottlenecks to overcome for 3D printed microneedles to achieve the mechanical performance needed for various clinical applications. The hierarchical structures in limpet teeth, which are extraordinarily strong, result from aligned fibers of mineralized tissue and protein‐based polymer reinforced frameworks. These structures provide design inspiration for mechanically reinforced biomedical microneedles. Here, a bioinspired microneedle array is fabricated using magnetic field‐assisted 3D printing (MF‐3DP). Micro‐bundles of aligned iron oxide nanoparticles (aIOs) are encapsulated by polymer matrix during the printing process. A bioinspired 3D‐printed painless microneedle array is fabricated, and suitability of this microneedle patch for drug delivery during long‐term wear is demonstrated. The results reported here provide insights into how the geometrical morphology of microneedles can be optimized for the painless drug delivery in clinical trials.