Smart Hydrogels: Theory and Applications with Particular Focus on Biomedical Sciences

Smart and intelligent materials provide direct or indirect solutions for many of the current/existing problems. Studies in this line have been in progress since few decades developing multifunctional materials, smart systems etc., for specific applications. Though many smart materials were developed, not much of them are compatible as implants in human body. One such material that possesses the inherent requirements attuned with human body is ‘hydrogel’. Like other smart materials, gels can also be intelligent in their responses to the environments they are exposed to, or on influence of any induced stimuli. Many such smart gels are explored by various industries and are used for applications such as drug delivery systems, cancer therapy, tissue engineering and organ printing, but a comprehensive understanding with properties, and their mechanisms regarding their functionality and usage are meagre. This work consolidates and details the classification of gels and elaborates the various stimuli to which gels respond and the mechanisms involved. This article also explores the possibilities, prospects of 3D-printing of smart gels in biomedical field and has listed the possible applications of hydrogels.

Keywords: 4D printing, Additive manufacturing, Artificial lens, Artificial muscles, Bimodal, Biochemical, Cross-linking, Drug delivery, Hydrogels, Hydrophilic, Hydrophobic, Organ printing, Self-healing, Shape memory hydrogels, Smart gels, Spinodal, Stimuli responsive, Superporous, Supramolecular, Tissue engineering.