Electrospinning Equipment: Silk protein is used to prepare skin sensors with finger-triggered color/transmittance adjustment

Research background and motivation

Silk fibroin, as a long-standing biocompatible material, has become one of the ideal platforms for skin and implantable electronic devices, especially self-powered systems, due to its excellent biocompatibility and biodegradability. However, the inherent brittleness and poor chemical stability of pure silk films limit its application. To solve this problem, researchers introduced mesoscopic doped regenerated silk to improve its mechanical flexibility and chemical stability, thereby expanding its application in self-powered systems.

Research methods and process

Mesoscopic doped regenerated silk: By introducing mesoscopic doped regenerated silk, its secondary structure transformation is promoted, and the mechanical flexibility (stretchable ~250%, bending cycle 1000 times) and chemical stability (resistant to 100℃ and pH3-11) of silk fibroin are significantly improved.

Preparation of composite SF electrode: Polyurethane (PU) is added to silk fibroin (SF) to promote the β-folding formation of SF. PU is successfully embedded in the SF β-crystal network, together forming a mixed SF mesostructure. Glycerol is added to the PU-SF film to enhance the waterproof performance of the film.

Development and testing of SF-TENG: Based on the composite SF electrode, a flexible, stretchable, and fully bioabsorbable triboelectric nanogenerator (TENG) was developed. The mechanical energy generated by finger movement is self-powered, and the signal is wirelessly transmitted to the receiver to control the transmittance change of the electrochromic rearview mirror.

Key conclusions and results

Improved mechanical and chemical properties: Mesoscopic doping with regenerated silk significantly improves the mechanical flexibility and chemical stability of silk protein films, making them adaptable to a wider range of application scenarios.

Superior performance of SF-TENG: The natural SF-TENG has a current of ~3μA, a voltage of ~50V, and a charge of ~24nC, which has significant advantages over traditional generators in terms of bending resistance, skin affinity, and self-powered efficiency.

Smart car application demonstration: The control system of the self-powered electrochromic car rearview mirror device controlled by SF-TENG was successfully demonstrated. The driver can control the electrochromic function of the rearview mirror through the SF-TENG device, effectively preventing the interference of the high beam of the rear vehicle on the line of sight and improving the safety of night driving.

Potential application of electrospinning equipment in the preparation of composite silk protein electrodes

Preparation of nanofiber structure: Electrospinning technology can produce long fibers with smaller diameter and higher surface area to volume ratio. This helps to prepare composite silk protein nanofibers with specific structure and properties, providing a basis for the construction of composite SF electrodes.

Regulating fiber morphology and arrangement: By adjusting the parameters in the electrospinning process (such as spinning solution concentration, viscosity, electric field strength, etc.), the diameter and morphology of nanofibers can be precisely controlled. This allows the arrangement and orientation of composite silk protein fibers to be precisely regulated, thereby optimizing the performance of the electrode.

Loading conductive materials: Electrospinning equipment can prepare nanofibers loaded with conductive materials (such as carbon nanotubes, graphene, etc.). Loading conductive materials into composite silk protein nanofibers can further improve the conductivity and charge transfer performance of the electrode, and enhance the self-powered efficiency of TENG.

Summary and Outlook

This study successfully developed a flexible, stretchable, and fully bioabsorbable triboelectric nanogenerator (TENG) through the preparation of mesoscopic doped regenerated silk and composite SF electrodes, which shows great application potential in smart cars, smart homes, and healthcare systems. Future research can further explore the application of electrospinning technology in the preparation of composite silk protein electrodes, improve the performance of electrodes by optimizing material selection and spinning process parameters, and promote their widespread application in self-powered systems.

Electrospinning Nanofibers Article Source:

https://doi.org/10.1021/acsnano.1c05257