Current Advances in Stimuli-Responsive Hydrogels as Smart Drug Delivery Carriers

Abstract

In recent years, significant advancements in the field of advanced materials and hydrogel engineering have enabled the design and fabrication of smart hydrogels and nanogels that exhibit sensitivity to specific signals or pathological conditions, leading to a wide range of applications in drug delivery and disease treatment. This comprehensive review aims to provide an in-depth analysis of the stimuli-responsive principles exhibited by smart hydrogels in response to various triggers, such as pH levels, temperature fluctuations, light exposure, redox conditions, or the presence of specific biomolecules. The functionality and performance characteristics of these hydrogels are highly influenced by both their constituent components and fabrication processes. Key design principles, their applications in disease treatments, challenges, and future prospects were also discussed. Overall, this review aims to contribute to the current understanding of gel-based drug delivery systems and stimulate further research in this rapidly evolving field.

Injectable Hydrogels for Nervous Tissue Repair—A Brief Review

“…Hydrogels produced in situ undergo a transition from a solution to a gel state, triggered by stimuli such as temperature, pH, or irradiation [ 91 , 92 ]. They can incorporate primary cells, stem cells, growth factors, and differentiating factors in situ in the matrix during the transition, leading to the formation of a three-dimensional (3D) scaffold for tissue engineering applications [ 23 , 93 ].…”

Biomedical Trends in Stimuli-Responsive Hydrogels with Emphasis on Chitosan-Based Formulations

“…One such chemical moiety is the disulfide linker, which may be broken down in the presence of reducing agents such as glutathione. Another one that may also respond to reactive oxygen species, such as hydrogen peroxide (H 2 O 2 ), is the selenide group [18,83]. Redox sensitivity is frequently integrated into structures that respond to other factors, e.g., pH or light [84].…”

“…Their biocompatibility, biodegradability, and the ability to encapsulate and release the drug make them attractive and highly applicable molecular carriers. Thus, it is no wonder that chitosan-based formulations are employed in neurological disorders, diabetes, tumors, and cardiovascular diseases [16][17][18][19].…”

“…Hydrogels are being constantly improved to provide superior clinical results. Among the upgrades, stimuli-responsive formulations are worth exploring since they react and adjust in response to various external stimuli such as pH, temperature, light, electric field, or ions [18]. Some are developed with multi-responsive properties to react to stimuli such as pH and reducing or oxidizing agents.…”

Preparation of PLGA Microspheres Using the Non-Toxic Glycofurol as Polymer Solvent by a Modified Phase Inversion Methodology

“…The problems of poor medication compliance and wide hazardous swings in drug levels particularly occur when repeat parenteral or enteral administration is required. Some of the new drug delivery technologies have included pump administration of drugs, utilization of gels, and the parenteral administration of drug laden microcrystals, lipospheres, and polymers [1][2][3][4][5][6].…”