# Directed Functionalization of Recombinant Spider Silk Nonwoven Membranes with Antibodies Using Non‐Canonical Amino Acids

## TL;DR

Scientists modified spider silk proteins to attach antibodies, creating functional membranes for biomedical uses.

## Contribution

A scalable method to genetically encode azido-groups in spider silk proteins for site-specific antibody attachment.

## Key findings

- Azido-groups were successfully incorporated into recombinant spider silk proteins using non-canonical amino acids.
- Antibodies were attached to spider silk nonwoven membranes via bio-orthogonal chemistry.
- The functionalized membranes show potential for bio-separation and biomedical applications.

## Abstract

Natural spider silk fibers are recognized for their outstanding mechanical properties. The production of underlying recombinant spider silk proteins in scalable quantities unlocks their potential for technical and biomedical applications. The recombinant spider silk technology further enables the introduction of new functions via genetic encoding. In the present study, the non‐canonical amino acid L‐azidohomoalanine is incorporated into the engineered Araneus diadematus fibroin 4, eADF4(C16), at positions explicitly defined by methionine codons in an N‐terminal peptide tag. The azido‐functionalized eADF4(C16) is processed into particles, films, or electrospun into nanofibers. As functional entities, high molecular weight molecules, such as antibodies, are modified with bio‐orthogonal groups suitable for strain‐promoted cycloaddition to the exposed azido‐groups on the spider silk supports. The antibody‐activated spider silk nonwoven meshes exemplarily show their applicability as bio‐capturing membranes.

A recombinant spider silk protein was functionalized by incorporating genetically encoded bio‐orthogonal reactive azido‐groups. The azido‐functionalized proteins were produced in a scalable biotechnological process, and particles, films, as well as nanofibers were established as anchorage for fully functional antibodies via site‐specific bio‐orthogonal chemistry. Spider silk nonwoven membranes decorated with antibodies constitute a cutting‐edge tool for bio‐separation processes as well as other applications.