Vol 92, No 2 (2023)

The progress in the field of tissue engineering is largely driven by the development of 3D laser printing technologies, which allow precise creation of hydrogel scaffolds containing cells (the so-called tissue-engineered constructs), using photoinduced radical reactions of polymerization and crosslinking. The review considers the main mechanisms and features of such reactions, presents the most common materials for photocompositions, including natural and synthetic polymers and precursors, and describes various mechanisms for photoinitiator activation. Advances in the field of photopolymerization enable application of modern laser 3D printing techniques based on extrusion and stereolithography to design tissue-engineered constructs in a wide range of sizes and shapes with a finely organized architecture. The integration of such methods with the methods of bioengineering and cell technology is discussed, including for the creation of tissue-specific and in vivo polymerized constructs. The bibliography includes 225 references.

The review describes the dielectric elastomer actuators (DEAs), a class of soft mechanical actuators made of functional polymeric materials and composites, which are capable to act as artificial muscles. The principles of operation, design, methods of DEAs fabrication and the required equipment are comprehensively described. Most frequently used DEA polymers (polyacrylates, polyurethanes, siloxanes) are considered in detail, and various modern advanced modification methods are listed. Polydimethylsiloxanes (PDMSs) are the most promising materials as DEA membranes. The review presents the state-of-the-art techniques for significant improvement of the performance of PDMSs: the reinforcement of a silicone matrix with different dispersed fillers, the chemical modification using compounds with large dipole moments to finely tune the dielectric characteristics of the silicones, etc. A new classification of DEAs is proposed. The design of more than 20 DEA devices are presented. The bibliography includes 269 references.