AsianScientist (Mar. 25, 2019) – A research group from South Korea has invented a method to fabricate silk-based microelectronics. They published their method in ACS Advanced Materials & Interfaces.
Silk fibroins are biocompatible, biodegradable, transparent and flexible, which makes them excellent candidates for implantable biomedical devices. However, conventional microfabrication processes require strong etching solutions and solvents to modify the structure of silk fibroins.
To prevent the silk fibroin from being damaged during the process, researchers led by Professor Lee Hyunjoo at the Korea Advanced Institute of Science and Technology came up with a process called aluminum hard mask on silk fibroin (AMoS) to create micropatterns consisting of multiple layers of fibroin and inorganic materials.
The team was able to integrate metals and dielectrics with high-precision microscale alignment with the silk fibroins. Core to their technique was photolithography, in which light rather than solvents was used to etch out specific patterns.
Demonstrating the biocompatibility of the resultant silk-based electronics, the researchers successfully cultured primary neurons on the processed silk fibroin micropatterns. They confirmed that the neurons survived and retained their function on the silk fibroin, suggesting that the advanced material was suitable for use in implanted biological devices.
Scaling up their technology, the scientists further fabricated a biodegradable microelectric circuit consisting of resistors and silk fibroin dielectric capacitors in a silicon wafer over a large area. They also used their technique to micropattern silk fibroins closer to a flexible polymer-based brain electrode, and confirmed that the dye molecules mounted on the silk fibroin were transferred successfully from the micropatterns.
“This technology facilitates wafer-scale, large-area processing of sensitive materials. We expect it to be applied to a wide range of biomedical devices in the future. Using the silk fibroin with micropatterned brain electrodes can open up many new possibilities in research on brain circuits by mounting drugs that restrict or promote brain cell activity,” said Lee.
The article can be found at: Kook et al. (2018) Wafer-Scale Multilayer Fabrication for Silk Fibroin-Based Microelectronics.
Source: Korea Advanced Institute of Science and Technology; Photo: ACS Advanced Materials & Interfaces.
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