Engineering (Bio)Materials through Shrinkage and Expansion

Abstract

Although various (bio)fabrication technologies have achieved revolutionary progress in the past decades, engineered constructs still fall short of expectations owing to their inability to attain precisely designable functions. Shrinkable and expandable (bio)materials feature unique characteristics leading to size-/shape-shifting and thus have exhibited a strong potential to equip current engineering technologies with promoted capacities toward applications in biomedicine. In this progress report, the advances of size-/shape-shifting (bio)materials enabled by various stimuli, are evaluated; furthermore, representative biomedical applications associated with size-/shape-shifting (bio)materials are also exemplified. Toward the future, the combination of size-/shape-shifting (bio)materials and 3D/4D fabrication technologies presents a wide range of possibilities for further development of intricate functional architectures.

Three-dimensional printing of smart constructs using stimuli-responsive biomaterials: A future direction of precision medicine

“…Wang et al . [ 119 ] proposed a hybrid bioink with shape memory for drug delivery. Sodium alginate and Pluronic F127 diacrylate macromers (F127DA) were mixed to formulate shape-memory hydrogels (SMHs).…”

Responsive and self-healing structural color supramolecular hydrogel patch for diabetic wound treatment

“…Considerable efforts have been devoted to generating materials for the treatment of diabetic wound, such as rubber, nanofibers, porous foams, and hydrogel patches [ [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] ]. Among them, hydrogel patches show great potential in diabetic wound healing due to their deformability, moisture retention, as well as the advantages of internalizing and delivering actives at the wound interface [ [24] , [25] , [26] , [27] , [28] ]. Although with much progress, the existing hydrogel patches are usually with simple composition or structures, which would restrict their functional performance in responsiveness, antibacterial and anti-inflammatory capabilities.…”

Multi‐Responsive Jammed Micro‐Gels Ink: Toward Control over the Resolution and the Stability of 3D Printed Scaffolds

“…[ 24 ] To overcome the technological limitations, post‐printing treatment strategies have been employed to increase the resolution of the printed constructs. [ 25,26 ] These strategies can be encompassed by the generic term 4D printing where time is considered as a fourth dimension. [ 27,28 ] For instance, Gong et al., printed a set of negatively charged hyaluronic acid or alginate methacrylate scaffolds that were further electrostatically complexed with free positively charged chitosan chains, inducing a shrinkage of the structure up to over 50%.…”

“…Another strategy that revealed to be efficient in controlling the shrinkage of a hydrogel construct is a temperature induced swelling/deswelling. [ 26 ] One of the most famous thermosensitive water‐soluble polymers is poly( N ‐isopropylacrylamide), pNiPAM, which can undergo a reversible hydrophilic/hydrophobic transition at so called Lower Critical Solution Temperature (LCST), determined to be ≈32 °C in water. [ 29 ] Up to now, this temperature induced shrinkage has been used to develop temperature sensitive 3D printed hydrogel actuators but remain unexplored to control the resolution of printed scaffolds.…”