Extracellular micro and nanostructures forming the velvet worm solidified adhesive secretion

Abstract

Advances in nanotechnology and molecular biology have promoted material development using bio-inspired approaches [1]. Nano-defined self-assemblies derived from biological systems have been used as an inspiration for the innovative development of materials, such as bio-adhesives that could work efficiently in water using cross-linked non-toxic components. Some animals and plants produce adhesive secretions for prey capture, defence, prevention of dehydration, and camouflage, among other things; and have been used as the inspiration for the design of new adhesives to be applied in the medical, bio-electronical, textile and cosmetics industries [ 2, 3]. Recent examples include mussels, frogs, ivy plants, sandcastle worms, geckos, sea cucumbers and tubeworms [4-12]. Each organism has its own features and the physicochemical characterization of biological derivate secretions is challenging. In general, these secretions are composed mainly of mixtures of proteins, carbohydrates, surfactants, peptides, water and some ions like Ca 2+. Natural adhesives usually consist of complex biopolymer blends, forming in many cases extracellular nanometric structures that play a key role in the adhesion mechanism. Some of the functions of the extracellular nanostructures are attributed to the enhancement of energy dissipation, as it is frequently found in climbing animals that produce fibrillary structures. These structures are thought to be responsible for a mechanism analogous to the molecular stretching of polymeric chains and also, through their nanostructures, to influence the contact points with the target surfaces to minimize crack length and propagation [10].

Reversible Supramolecular Assembly of Velvet Worm Adhesive Fibers via Electrostatic Interactions of Charged Phosphoproteins

“…2 More remarkable, perhaps, is the fact that fiber formation is completely reversible and circular−dry fibers from E. rowelli dissolve in water after several hours and new fibers can be regenerated from the dissolved fiber solutions. 2,9 The fact that velvet worm fiber formation occurs outside the body sets this fabrication process apart from other biopolymer assembly processes that involve biomediated control of processing conditions (e.g., silks 10 and mussel byssus 5 ), making it highly relevant for biomimetic transfer into synthetic polymer systems. However, this first requires a more in-depth understanding of the molecular level driving forces controlling reversible supramolecular assemblya response that must be programmed in the fluid itself.…”

A new giant velvet worm from Costa Rica suggests absence of the genus Peripatus (Onychophora: Peripatidae) in Central America

“…, and the capacity of expelling an adhesive net (Bouvier, 1905;Haritos et al, 2010;Concha et al, 2015;Corrales-Ureña et al, 2017;Baer, Hänsch, Mayer, Harrington, & Schmidt, 2018). They have been considered living fossils (Garwood et al, 2016).…”

Onychophorology, the study of velvet worms, historical trends, landmarks, and researchers from 1826 to 2020 (a literature review)

“…Other studies from this time dealt with the nanostructures of the solidified adhesive secretion (Corrales-Urena et al, 2017), the assembling of fibers by electrostatic interactions in phosphoproteins (Baer, Hänsch, Mayer, Harrington, & Schmidt, 2018), and a mimic of onychophoran skin, which is slippery to the adhesive, produced with microporous porphyrin networks (Ryu et al, 2018).…”