Bio-based and bio-inspired adhesives from animals and plants for biomedical applications

Abstract

With the “many-headed” slime mold Physarum polycelphalum having been voted the unicellular organism of the year 2021 by the German Society of Protozoology, we are reminded that a large part of nature's huge variety of life forms is easily overlooked – both by the general public and researchers alike. Indeed, whereas several animals such as mussels or spiders have already inspired many scientists to create novel materials with glue-like properties, there is much more to discover in the flora and fauna. Here, we provide an overview of naturally occurring slimy substances with adhesive properties and categorize them in terms of the main chemical motifs that convey their stickiness, i.e. , carbohydrate-, protein-, and glycoprotein-based biological glues. Furthermore, we highlight selected recent developments in the area of material design and functionalization that aim at making use of such biological compounds for novel applications in medicine – either by conjugating adhesive motifs found in nature to biological or synthetic macromolecules or by synthetically creating (multi-)functional materials, which combine adhesive properties with additional, problem-specific (and sometimes tunable) features.

Multifunctional “Janus‐Type” Bilayer Films Combine Broad‐Range Tissue Adhesion with Guided Drug Release

“…To date, many different adhesive formulations-mostly in the form of hydrogels-have been introduced to achieve better mechanical properties than those provided by commercial adhesives used in clinical applications. [7][8][9][10][11][12] To tackle the problems associated with using surgical sutures (e.g., requiring expert skills and a suture removal appointment), very promising materials with strong adhesion properties were developed in the last years. Recent examples include a polyethylenimine-poly(acrylic acid) powder for closing gastrointestinal perforations, [13] poly(vinyl alcohol)-dihydroxyphenylalanine (DOPA) films for the delivery of drugs to wet buccal tissue, [14] and macroporous carboxymethyl/agarose hydrogels for the delivery of Ag + ions.…”

Bio-Based Adhesives for Orthopedic Applications: Sources, Preparation, Characterization, Challenges, and Future Perspectives

“…Based on biomechanical studies, it is known that these bio-adhesive polymers have better strength of bio-adhesion when compared to fibrin glue, but they also have a poorer strength of bio-adhesion than cyanoacrylates on bovine cortical bone specimens. Excellent biocompatibility was also demonstrated in in vitro cell testing, so this bio-based adhesive can be a promising candidate for clinical utilization [21,42,[46][47][48].…”

Recent Advances in Mucoadhesive Interface Materials, Mucoadhesion Characterization, and Technologies

“…[56][57][58][59] For instance, it has been demonstrated that a properly applied mucin or mucin-mimic coating not only maintains good biological adhesion properties but also decreases friction (especially in the boundary lubrication regime), reduces wear damage, and provides antibiofouling properties. [60]…”