The Application of Laser Micromachining Technology in Biological Application Devices
Application Two
Manufacturing of Medical MEMS Components
Micro-electromechanical system technology is based on the 21st century technology based on micron and nanotechnology. Since the 1980s, it has been applied to the medical industry, and its related technologies and products have been covered in biomedicine fields such as detection, diagnosis, and treatment. At present, MEMS processing technology is mainly a technology for processing silicon-based materials using chemical etching or integrated circuit processes. However, due to the characteristics of medical MEMS processing objects and industrial applications, there are great differences and new technologies and new materials are used in medical treatment. With the continuous application of the field, traditional silicon-based processing methods have not been applied to the processing of medical MEMS. Compared with the traditional silicon-based processing technology, laser micromachining technology not only applies to a variety of materials, but also can process 3D micro-structures with sub-micron precision. It has a good application prospect in the processing of medical MEMS.
The use of high-density microelectrode arrays to arouse or record neural activity is a very complex and important research topic in the field of neural prostheses. Green et al. fabricated a portable high-density microelectrode array using femtosecond laser microfabrication technology using conventional PDMS and platinum (Pt) foil materials. The results show that the surface structure of the microelectrode array produced by the laser micromachining method is uniform and roughness. Preferably, the maximum electrode spot thickness in the array is about 200 μm.
Aluminum nitride (AlN) materials have low reactivity in biological environments and are very suitable for making biocompatible devices. Using sapphire as the base material, a waveguide array structure is fabricated on the surface of the AlN film and can be combined with a microfluidic system for drug delivery. Safadi et al. used excimer laser micromachining to fabricate a waveguide structure on a sapphire-based AlN film. This structure combined with microfluidics can play an important role in drug delivery in nervous tissues.
Minimally invasive surgical tools play an important role in biomedical diagnosis and treatment, and catheters are involved in many minimally invasive surgical tools. Compared to conventional passive catheters, active control of tipped catheters enables greater precision and efficiency. Lee et al. prepared a polypyrrole (PPy)-based artificial muscle-driven catheter by laser micromachining technology and demonstrated the controllability of the prepared four-electrode catheter by two-dimensional bending motion, as shown in the figure. The combination of an active catheter produced by micromachining and optical coherence tomography enables visualization of the subsurface of the biological tissue, confirming the superior imaging capabilities of using this structural design.
Figure PPy-based active catheter prepared by laser micromachining. (a) Four-electrode catheter design structure; (b) Four-electrode catheter SEM image prepared by laser micromachining; (c) PPy bending motion at one end of the catheter
Silicon wafers are commonly used biomaterials to prepare biomaterials. Wongwiwat et al. studied the effects of micro-channel array structures and square structures processed on the surface of silicon wafers using laser micromachining technology on the biological characteristics of silicon wafers, indicating that the micro-structure of the silicon wafer surface can be Increase protein absorption. Although this will cause cardiovascular or blood-related medical devices to produce thrombi during application, enhanced protein absorption can also promote cell expansion. This applies to biomedical implanted MEMS devices such as microchips, pressure sensors, and drug delivery systems. The application is very helpful.
The problem of the preparation of 3D-shaped micro/nano fiber structures has always been a problem that cannot be effectively applied in the field of tissue engineering. Kim et al. used femtosecond laser processing technology to process 3D pore structures on 3D micro/nano fiber structures produced by electrospinning.
Peripheral nerve regeneration element is a multi-layer polymer structure made of biomaterials such as poly-D-lactic acid (PDLA) and polyvinyl alcohol (PVA). The PDLA film is degradable in 4-6 months, and the PVA film is Dissolve in about two weeks at 37 °C. The results of Kancharla et al's 2002 experiments demonstrated that laser micromachining technology is feasible for the preparation of biodegradable micro-medical devices.
The miniaturization of biomedical components, especially the transition from biomicrodevices to biomaterials, is a challenge for researchers. In the area of improvement of medical devices, prevention, diagnosis and treatment of diseases, MEMS have potential applications. Miniaturization is an important feature of MEMS. With the continuous development of MEMS technology in the biomedical field, how to accurately and rapidly process increasingly complex and precise components has become an important issue for MEMS development in the biomedical field.
Laser micromachining technology makes it impossible for conventional micromachining methods to realize medical microelectromechanical products such as medical catheters, microchips, and drug delivery systems. Although the application of laser micromachining technology in biomedical MEMS has just started, but the direct laser micromachining and laser stereolithography based on the laser ablation mechanism have received more and more attention and research, laser micromachining technology is bound to Promote the wide application of MEMS in biomedical and promote the development of modern medical engineering.