Spider Silk: Mother Nature’s Bio-Superlens

Abstract

It was recently discovered that transparent microspheres and cylinders can function as a super-resolution lens (i.e., superlens) to focus light beyond the diffraction limit. A number of high-resolution applications based on these lenses have been successfully demonstrated and span nanoscopy, imaging, and spectroscopy. Fabrication of these superlenses, however, is often complex and requires sophisticated engineering processes. Clearly an easier model candidate, such as a naturally occurring superlens, is highly desirable. Here, we report for the first time a biological superlens provided by nature: the minor ampullate spider silk spun from the Nephila spider. This natural biosuperlens can distinctly resolve 100 nm features under a conventional white-light microscope with peak wavelength at 600 nm, attaining a resolution of λ/6 that is well beyond the classical limit. Thus, our work opens a new door to develop biology-based optical systems that may provide a new solution to integrating optics in biological systems.

Combination of scanning probe technology with photonic nanojets

“…Importantly, in most existing literature a strict definition of spatial resolution is not used. For instance, a common parameter used to quantify resolution is the 100 nm width of the stripes of Blu-ray disks 9, 21, 25, 33–36 . Because these stripes are periodically separated from each other a typical distance of 200 nm, the parameter that defines resolution in this case is related to the total periodicity of the structure (~300 nm), as convolution with different size PSF shows 37 .…”

De Novo Design of Recombinant Spider Silk Proteins for Material Applications

“…For instance, flagelliform silk‐inspired artificial fibers have been successfully utilized for collecting water from humid air . Minor ampullate and cylindriform silks have been processed into an optical super‐lens to resolve sub‐diffraction objects and patterns (≈100 nm) …”

“…Three promising de novo routes have emerged in recent years: (i) genetic synthesis of high molecular weight RSSPs; (ii) multiscale self‐assembly of RSSPs; and (iii) design and optimization of the RSSP sequences through computational simulation . These strategies significantly improved the mechanical performance of RSSP materials and even imbued them with additional functions, such as energy absorption, water collection, optical elements, biomaterials for chondrocyte regeneration, and as nerve conduits …”

“…Three promising de novo routes have emerged in recent years: (i) genetic synthesis of high molecular weight RSSPs; (ii) multiscale self-assembly of RSSPs; and (iii) design and optimization of the RSSP sequences through computational simulation. [23][24][25][26][27][28] These strategies significantly improved the mechanical performance of RSSP materials and even imbued them with additional functions, such as energy absorption, [29] water collection, [30] optical elements, [31,32] biomaterials for chondrocyte regeneration, [33] and as nerve conduits. [17,34,35] In this article, we first introduce the material design strategies for natural spider silk and focus on the discussion of the structure-property-function relationships for the spider silk.…”

Parameter determination and transformation for the focusing of dielectric microspheres illuminated by optical needle

“…Microspheres have recently attracted numerous attentions in the field of super-resolution due to its sub-diffraction focusing size and magnification of objects ahead of it 1–7 , and have been used in nano-scale imaging 8, 9 , nano-scale lithography 10, 11 etc. The physical mechanism of sub-diffraction focusing size of microsphere is that microspheres have naturally negligible spherical aberrations (SAs) and high numerical aperture (NA) when the refractive index ratio (RIR) between the microsphere and its surrounding medium and the radius of microsphere are designed properly 12 .…”