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Laser based additive manufacturing (AM) methods, that incorporate a high-density laser to sinter, melt, or solidify the desired material, have developed into an ideal technology for the design and fabrication of robust and highly customizable functional devices which aim to address key challenges in the aerospace, biomedical, and defense sectors. Recent advancements in powder bed fusion (PBF) approaches, such as selective laser sintering (SLS) and melting (SLM) have significantly improved the range of printable materials, minimum feature size, and microstructure evolution, endowing precise control over the physical properties of the final printed part. Furthermore, studies on novel photoresist materials and laser scanning strategies used during multiphoton lithography (MPL) approaches indicated that nanoscale spatial resolution could be achieved, allowing for the design of intricate biomedical implants or smooth optical devices. This chapter focuses on an extensive review of current research being conducted on laser-based AM technologies highlighting the current compatible materials and applications of SLS, SLM, and MLP printed functional devices. Future perspectives and notable challenges of the laser-based AM technologies are discussed in detail with the purpose of identifying critical research areas for each methodology. 

Abstract The cell is a microcapsule system wherein biological materials are encapsulated by a thin membrane, which provides valuable information on the metabolism, morphology, development, and signal transduction pathways of the studied cell. The cell-inspired microdroplet has the characteristics of efficient nanoscale substance transportation, self-organization, and morphological adaptation. However, it is extremely difficult to manufacture such systems. Mostly vesicles such as liposomes, polymersomes, and microcapsules are first produced by a high-pressure homogenizer and microfluidizer as an emulsion and then encapsulated microcapsules by the drop or emulsion method. Currently, acoustic levitation opens entirely new possibilities for creating bioinspired microdroplets because of its ability to suspend tiny droplets in an antigravity and noncontact manner. Herein, we propose contactless printing of single-core or multi-core cell-inspired microdroplets via acoustic levitation. First, the oscillation mode and microscopic morphology of the droplets under different ultrasonic vibration frequencies are shown by simulation, and the curing characteristics of the shell structure under different ultraviolet illumination conditions are quantitatively measured. The feasibility of manufacturing multi-core microdroplets and manufacturing submillimeter-scale particles based on oil trapping is extensively studied. To explore the morphological adaptability of microdroplets, ferromagnetic Fe3O4 nanoparticles are used to give magnetic-responsive properties to cells, and the microscopic deformation and motion in microfluidic channels under the magnetic field are characterized. Finally, the proposed printing method proves the versatility of in-space contactless printing of complex 3D beam structures and provides a powerful platform for developing biomedical devices and microrobots and studying morphogenesis and synthetic biological systems. 

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.