Flexible bioelectronics and micro-optical systems

生物电子学和微光学是新兴技术，将对医疗保健和医药、食品安全监控、智能包装、可穿戴传感器和公共安全的未来产生重大影响。生物电子学涉及功能生物材料与微电极、光电传感器和半导体器件的接口。各种各样的催化剂（酶）、生物分子（蛋白质、脂质、核酸）、微生物和神经细胞都可以用来提供高效的分子识别和结合能力。附着在生物组织、植物、薄人造膜和纺织品上的电子和光电子电路也应该具有机械柔性，以便设备能够符合底层物体的形状。导电油墨（PEDOT:PSS, Au, Ag）的最新进展鼓励研究人员探索按需滴印技术，作为在各种可弯曲和可拉伸基材上创建互连和电极的可行方法。印刷技术还能够在微电路表面上分配皮升的透明热塑性微滴，以制造波导、微透镜和光子结构。西部大学的初步研究表明，导电石墨烯和半导体氧化石墨烯（GO）可以由廉价的石墨粉末合成，并分散在溶剂中形成可印刷的油墨。一旦氧化石墨烯油墨沉积在衬底上，可以通过使用激光诱导加热的热还原来部分恢复导电性。这种“可调带隙”使得热还原氧化石墨烯（rGO）成为直接在印刷电路上制造各种电子元件（电阻器、二极管、晶体管）的潜在有用材料。激光微加工技术还可用于在导电薄膜上刻印纳米/微尺度图案，修改局部光学特性，或去除多余的薄膜和衬底材料。功能材料、先进制造和生物医学技术都被NSERC认定为有利于我国经济和提高所有加拿大人生活质量的战略领域。这项研究计划的长期目标是推进设计策略和制造方法，用于创造下一代机械柔性，可拉伸的生物电子设备和生物集成系统。成功将取决于对喷墨印刷电极和电路的机械、电气和光学特性的基础研究，以及激光微加工局部改变这些特性的能力。未来五年的具体研究目标是：(1)研究按需制造和激光微加工方法，以打印和局部“调整”石墨烯基微结构的电学、光学和机械性能；（O2）利用机械设计原理来增强印刷在各种柔性基材（聚合物，纸张，纺织品）上的电极和互连的功能（电气和光学性能）和可拉伸性；(3)建立生物功能化机械柔性印刷电路的方法和指南；（O4）探索印刷柔性生物电子和光电子电路在患者健康监测、可穿戴身体传感器、智能食品包装和大面积成像方面的创新应用。

Bioelectronics and micro-optics are emerging technologies that will significantly impact the future of healthcare and medicine, food safety monitoring, smart packaging, wearable sensors, and public security. Bioelectronics involves interfacing functional biomaterials with microelectrodes, optoelectronic sensors, and semiconductor devices. A wide variety of catalysts (enzymes), biomolecules (proteins, lipids, nucleic acids), micro-organisms and neural cells can be used to provide highly effective molecular recognition and binding capabilities. The electronic and optoelectronic circuitry attached to biological tissue, plants, thin artificial membranes, and textiles should also be mechanically flexible so that the device can conform to the shape of the underlying object. Recent advances in electrically conductive inks (PEDOT:PSS, Au, Ag) have encouraged researchers to explore drop-on-demand printing technology as a viable approach for creating interconnects and electrodes on a variety of bendable and stretchable substrates. Printing technology is also capable of dispensing picoliter droplets of transparent thermoplastic on microcircuit surfaces to fabricate waveguides, microlenses and photonic structures. Preliminary research at Western has shown that electrically conductive graphene and semiconductive graphene-oxide (GO) can be synthesized from inexpensive graphite powders and dispersed in solvents to form printable inks. Once the GO ink is deposited on a substrate the electrical conductivity can be partially restored through thermal reduction using laser-induced heating. This "tunable band-gap" makes thermally reduced graphene-oxide (rGO) a potentially useful material for creating a variety of electronic components (resistors, diodes, transistors) directly on the printed circuits. Laser microfabrication techniques can also be used to imprint nano/micro-scaled patterns on the conductive films, modify the local optical characteristics, or remove excess film and substrate material. Functional materials, advanced manufacturing, and biomedical technologies are all recognized by NSERC as strategic areas that will benefit our country's economy and improve the quality of life for all Canadians. The long-term goal of this research program is to advance the design strategies and fabrication methods used to create the next generation of mechanically flexible, stretchable bioelectronic devices and bio-integrated systems. Success will depend on fundamental studies of the mechanical, electrical and optical characteristics of inkjet-printed electrodes and circuits, and the ability of laser microfabrication to locally alter these properties. The specific research objectives over the next five years are to: (O1) investigate drop-on-demand fabrication and laser micromachining methods to print and locally "tune" the electrical, optical and mechanical properties of graphene-based microstructures; (O2) exploit the principles of mechanical design to enhance the functionality (electrical & optical properties) and stretchability of electrodes and interconnects printed on various flexible substrates (polymers, paper, textiles); (O3) establish methods and guidelines for bio-functionalizing mechanically flexible printed circuits; and (O4) explore innovative applications of printed flexible bioelectronic and optoelectronic circuitry in patient health monitoring, wearable body sensors, smart food packaging, and large area imaging.