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Nanoscale lithography and information storage in biocompatible materials offer possibilities for applications such as bioelectronics and degradable electronics for which traditional semiconductor fabrication techniques cannot be used. Silk fibroin, a natural protein renowned for its strength and biocompatibility, has been widely studied in this context. Here, we present the use of silk film as a biofunctional medium for nanolithography and data storage. Using tip-enhanced near-field infrared nanolithography, we demonstrate versatile manipulation and characterize the topography and conformation of the silk in situ. In particular, we fabricate greyscale and dual-tone nanopatterns with full-width at half-maximum resolutions of ~35 nm, creating an erasable ‘silk drive’ that digital data can be written to or read from. As an optical storage medium, the silk drive can store digital and biological information with a capacity of ~64 GB inch−2 and exhibits long-term stability under various harsh conditions. As a proof-of-principle demonstration, we show that this silk drive can be biofunctionalized to exhibit chromogenic reactions, resistance to bacterial infection and heat-triggered, enzyme-assisted decomposition. A silk drive can store digital and biological information with a capacity of about 64 GB inch−2.

Breaking the optical diffraction limit is a prerequisite for the manufacturing and functioning of nanophotonics devices working with long-wavelength light. The near-field evanescent wave can serve as one powerful mean to induce locally confined high-field optical phenomena, enabling fabrication, manipulation, and characterization of photo-sensitive structures at the nanoscale. Here, we report a rewritable optical storage medium made of silk proteins (termed "silk-drive") using a home-built tip-enhanced near-field infrared (IR) nano-optics system capable of both "writing" & "reading" information at a resolution of ~ 35 nm (i.e., a storage capacity of ~ 64 GB inch-2). Moreover, thanks to the fine biological compatibility of silk protein, the silk-drive can store biological information, which can not be achieved by traditional semiconductor-based hard disks. Our method promises great potential in the local-manipulation of optically and/or biologically functional devices and unravels a novel way to perform nanometric and "green" photolithography in biomaterials.

Nanoscale lithography and information storage in biocompatible materials offer possibilities for applications such as bioelectronics and degradable electronics for which traditional semiconductor fabrication techniques cannot be used. Silk fibroin, a natural protein renowned for its strength and biocompatibility, has been widely studied in this context. Here, we present the use of silk film as a biofunctional medium for nanolithography and data storage. Using tip-enhanced near-field infrared nanolithography, we demonstrate versatile manipulation and characterize the topography and conformation of the silk in situ. In particular, we fabricate greyscale and dual-tone nanopatterns with full-width at half-maximum resolutions of ~35 nm, creating an erasable 'silk drive' that digital data can be written to or read from. As an optical storage medium, the silk drive can store digital and biological information with a capacity of ~64 GB inch

We present tip-enhanced nearfield grayscale thermal nanolithography (TNTN), a closed-loop nanofabrication technique capable of patterning hierarchical 3D biostructures. A mid-IR monochromatic laser beam is coupled with an AFM tip to pattern sub-diffractional arbitrary nanostructures onto the surface of a silk protein resist with the FWHM spatial resolution down to 30 nm. We confirm via in-situ scattering-scanning nearfield optical microscopy that patterning induces topographical and phase change on the silk protein resist. Various TNTN patterning parameters can be used to control the dimensions of the nanostructures, as demonstrated by a proof-of-principle grayscale patterning. TNTN is wavenumber sensitive, doesn't require vacuum, and is minimally invasive.

A wafer‐scale high resolution patterning of bio‐microstructures is achieved using precise protein photolithography. In article number 1700191, the application of these micropatterned structures as cellular substrate for the successful spatial guidance of fetal neural stems cells using well‐defined silk fibroin light chain as the resist material is demonstrated by Tiger H. Tao and co‐workers.

Precise patterning of biomaterials has widespread applications, including drug release, degradable implants, tissue engineering, and regenerative medicine. Patterning of protein‐based microstructures using UV‐photolithography has been demonstrated using protein as the resist material. The Achilles heel of existing protein‐based biophotoresists is the inevitable wide molecular weight distribution during the protein extraction/regeneration process, hindering their practical uses in the semiconductor industry where reliability and repeatability are paramount. A wafer‐scale high resolution patterning of bio‐microstructures using well‐defined silk fibroin light chain as the resist material is presented showing unprecedent performances. The lithographic and etching performance of silk fibroin light chain resists are evaluated systematically and the underlying mechanisms are thoroughly discussed. The micropatterned silk structures are tested as cellular substrates for the successful spatial guidance of fetal neural stems cells seeded on the patterned substrates. The enhanced patterning resolution, the improved etch resistance, and the inherent biocompatibility of such protein‐based photoresist provide new opportunities in fabricating large scale biocompatible functional microstructures.

We report on wafer-scale high resolution patterning of bio-microstructures using silk fibroin light chain (L-fibroin) as the photoresist material. The L-fibroin fragments with the well-defined molecular weight have been successfully isolated from the integral silk fibroins consisting both heavy and light chains. Under facile biochemical modification, the L-fibroin photoresist can be synthesized via conjugating commercial photocrosslinkers as crosslinking sites in the presence of ultraviolet light. The enhanced patterning resolution, the improved etching selectivity and the inherent biocompatibility of such protein-based photoresist provide opportunities in large scale biocompatible functional microstructures manufacturing.

We present spectroscopic studies of nanoscale polymorphic transition of silk proteins under electrons using infrared scattering near-field optical microscopy (s-SNOM), which paves the way for unlocking essential nanoscopic hierarchical molecular structures in protein-based biomaterials.

We present a thermal nanolithography technique by using silk proteins as resist with scanning near-field optical microscopy, which is capable of capable of selective curing and in-situ characterization of natural silk proteins at nanoscale resolution.

Precise patterning of biomaterials has widespread applications, including drug release, degradable implants, tissue engineering, and regenerative medicine. Patterning of protein-based microstructures using UV-photolithography has been demonstrated using protein as the resist material. The Achilles heel of existing protein-based biophotoresists is the inevitable wide molecular weight distribution during the protein extraction/regeneration process, hindering their practical uses in the semiconductor industry where reliability and repeatability are paramount. A wafer-scale high resolution patterning of bio-microstructures using well-defined silk fibroin light chain as the resist material is presented showing unprecedent performances. The lithographic and etching performance of silk fibroin light chain resists are evaluated systematically and the underlying mechanisms are thoroughly discussed. The micropatterned silk structures are tested as cellular substrates for the successful spatial guidance of fetal neural stems cells seeded on the patterned substrates. The enhanced patterning resolution, the improved etch resistance, and the inherent biocompatibility of such protein-based photoresist provide new opportunities in fabricating large scale biocompatible functional microstructures.