A microneedle (MN) array is a novel biomedical device adopted in medical applications to pierce through the stratum corneum while targeting the viable epidermis and dermis layers of the skin. Owing to their micron-scale dimensions, MNs can minimize stimulations of the sensory nerve fibers in the dermis layer. For medical applications, such as wound healing, biosensing, and drug delivery, the structure of MNs significantly influences their mechanical properties. Among the various microfabrication methods for MNs, fused deposition modeling (FDM), a commercial 3D printing method, shows potential in terms of the biocompatibility of the printed material (polylactic acid (PLA)) and preprogrammable arbitrary shapes. Owing to the current limitations of FDM printer resolution, conventional micron-scale MN structures cannot be fabricated without a post-fabrication process. Hydrolysis in an alkaline solution is a feasible approach for reducing the size of PLA needles printed via FDM. Moreover, weak bonding between PLA layers during additive manufacturing triggers the detachment of PLA needles before etching to the expected sizes. Furthermore, various parameters for the fabrication of PLA MNs with FDM have yet to be sufficiently optimized. In this study, the thermal parameters of the FDM printing process, including the nozzle and printing stage temperatures, were investigated to bolster the interfacial bonding between PLA layers. Reinforced bonding was demonstrated to address the detachment challenges faced by PLA MNs during the chemical etching process. Furthermore, chemical etching parameters, including the etchant concentration, environmental temperature, and stirring speed of the etchant, were studied to determine the optimal etching ratio. To develop a universal methodology for the batch fabrication of biodegradable MNs, this study is expected to optimize the conditions of the FDM-based fabrication process. Additive manufacturing was employed to produce MNs with preprogrammed structures. Inclined MNs were successfully fabricated by FDM printing with chemical etching. This geometrical structure can be adopted to enhance adhesion to the skin layer. Our study provides a useful method for fabricating MN structures for various biomedical applications.

微针 (MN) 阵列是一种在医疗应用中采用的新型生物医学设备，用于刺穿角质层，同时针对皮肤的可行表皮和真皮层。由于其微米级尺寸，MNs 可以最大限度地减少对真皮层中感觉神经纤维的刺激。对于医学应用，如伤口愈合、生物传感和药物输送，MN 的结构显着影响其机械性能。在 MN 的各种微制造方法中，熔融沉积建模 (FDM)，一种商业 3D 打印方法，在打印材料（聚乳酸 (PLA)）的生物相容性和可预编程的任意形状方面显示出潜力。由于目前 FDM 打印机分辨率的限制，传统的微米级 MN 结构不能在没有后加工工艺的情况下制造。在碱性溶液中水解是减小通过 FDM 打印的 PLA 针尺寸的可行方法。此外，增材制造过程中 PLA 层之间的弱结合会在蚀刻到预期尺寸之前触发 PLA 针的分离。此外，使用 FDM 制造 PLA MN 的各种参数尚未得到充分优化。在这项研究中，研究了 FDM 印刷工艺的热参数，包括喷嘴和印刷台温度，以加强 PLA 层之间的界面粘合。增强的结合被证明可以解决 PLA MNs 在化学蚀刻过程中面临的分离挑战。此外，化学蚀刻参数，对蚀刻剂浓度、环境温度、蚀刻剂搅拌速度等因素进行了研究，以确定最佳蚀刻比例。为了开发可生物降解 MNs 的批量制造的通用方法，本研究有望优化基于 FDM 的制造过程的条件。增材制造被用来生产具有预编程结构的 MN。通过 FDM 印刷和化学蚀刻成功制造了倾斜的 MN。可以采用这种几何结构来增强对皮肤层的附着力。我们的研究为制造用于各种生物医学应用的 MN 结构提供了一种有用的方法。为了开发可生物降解 MNs 的批量制造的通用方法，本研究有望优化基于 FDM 的制造过程的条件。增材制造被用来生产具有预编程结构的 MN。通过 FDM 印刷和化学蚀刻成功制造了倾斜的 MN。可以采用这种几何结构来增强对皮肤层的附着力。我们的研究为制造用于各种生物医学应用的 MN 结构提供了一种有用的方法。为了开发可生物降解 MNs 的批量制造的通用方法，本研究有望优化基于 FDM 的制造过程的条件。增材制造被用来生产具有预编程结构的 MN。通过 FDM 印刷和化学蚀刻成功制造了倾斜的 MN。可以采用这种几何结构来增强对皮肤层的附着力。我们的研究为制造用于各种生物医学应用的 MN 结构提供了一种有用的方法。可以采用这种几何结构来增强对皮肤层的附着力。我们的研究为制造用于各种生物医学应用的 MN 结构提供了一种有用的方法。可以采用这种几何结构来增强对皮肤层的附着力。我们的研究为制造用于各种生物医学应用的 MN 结构提供了一种有用的方法。