This work presents electrospun nanofibers from synthetic spider silk protein, and their application as both a mechanical vibration and humidity sensor. Spider silk solution was synthesized from minor ampullate silk protein (MaSp) and then electrospun into nanofibers with a mean diameter of less than 100 nm. Then, mechanical vibrations were detected through piezoelectric characteristics analysis using a piezo force microscope and a dynamic mechanical analyzer with a voltage probe. The piezoelectric coefficient (d33) was determined to be 3.62 pC/N. During humidity sensing, both mechanical and electric resistance properties of spider silk nanofibers were evaluated at varying high-level humidity, beyond a relative humidity of 70%. The mechanical characterizations of the nanofibers show promising results, with Young's modulus and maximum strain of up to 4.32 MPa and 40.90%, respectively. One more interesting feature is the electric resistivity of the spider silk nanofibers, which were observed to be decaying with humidity over time, showing a cyclic effect in both the absence and presence of humidity due to the cyclic shrinkage/expansion of the protein chains. The synthesized nanocomposite can be useful for further biomedical applications, such as nerve cell regrowth and drug delivery.

Center of Advanced Materials Qatar University Doha 2713 Qatar

Center of Smart Nanotechnology and Photonics SmartCI Research Center Alexandria University Alexandria 21544 Egypt

Centre of Polymer Systems University Institute Tomas Bata University in Zlin Nad Ovcirnou 3685 Zlin 76001 Czech Republic

Department of Engineering Mathematics and Physics Faculty of Engineering Alexandria University Alexandria 21544 Egypt

Physics Department Kuwait College of Science and Technology Doha District 13133 Kuwait

USTAR Bioinnovations Center Utah State University Logan UT 84341 USA

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