The silk fiber produced by the silkworm is known as a lightweight and luxurious material. It has a history of thousands of years. Silk is a continuous long fiber made by solidifying the silk solution secreted during the cocoon formation of a mature silkworm. Although synthetic polymers such as nylon and polyester are cheaper, they are difficult to compare with the natural qualities and mechanical properties of silk. According to research from the University of Pittsburgh's Swanson School of Engineering, the combination of silk and carbon nanotubes may produce a new generation of biomedical devices and transient, biodegradable electronic devices.
The study "Promoting Helix-Rich Structure in Silk Fibroin Films through Molecular Interactions with Carbon Nanotubes and Selective Heating for Transparent Biodegradable Devices) was published on the cover of "Nano Materials" in the Journal of the American Chemical Society on October 26.
"Silk is a very interesting material. It is made of natural fibers. For thousands of years, humans have used natural fibers to make high-quality textiles, but as engineers, we have recently started to realize the potential of silk because it has Unique biocompatibility and biodegradability have great potential in many emerging fields, such as flexible bioelectronics. Mostafa Bedewy, an assistant professor of industrial engineering at Swanson College and the main author of the paper, said: "Silk also has a very Good flexibility. The problem is that if we want to use silk in this application, we don't want it to exist in the form of fibers. Instead, we want it to be regenerated silk protein, a membrane form that has the optical, mechanical and chemical properties we need . "
As the author explains in the video, these regenerated silk fibroin (RSF) are generally chemically unstable in water and have poor mechanical properties because it is difficult to precisely control the molecular structure of silk fibroin in the RSF membrane. Bedewy and his Nanoproducts Lab team have also extensively studied carbon nanotubes (CNTs), and they believe that molecular interactions between nanotubes and fibrin may "modulate" the structure of RSF proteins.
"An interesting aspect of carbon nanotubes is that when they are dispersed in a polymer matrix and exposed to microwave radiation, they are locally heated," Dr. Bedewy explained. So we want to know if we can use this unique phenomenon to produce the desired transformation in the silk fibroin structure around CNTs in "RSF-CNT" composites.
According to Dr. Bedewy, microwave radiation combined with solvent vapor treatment provides a unique control mechanism for protein structures that produces a flexible transparent film comparable to synthetic polymers, but this film is more sustainable and degradable . These RSF-CNT films have the potential to be used in flexible electronics, biomedical devices, and transient electronics (such as sensors). Such described transient electronics will use a certain desired period inside the body and then dissolve naturally.
Dr. Bedewy said: "We are excited to advance this work further because we look forward to developing technologies for these unique functional materials." From a scientific perspective, the functionalization of the nanotube surface and the molecular interactions between protein molecules There are still many things to understand. From an engineering perspective, we hope to develop a scalable manufacturing process for taking out natural silk cocoons and turning them into functional films for the next generation of wearable and implantable electronic devices. "