Smart stimuli-responsive injectable gels and hydrogels for drug delivery and tissue engineering applications: A review

Abstract

Hydrogels are widely used biomaterials in the delivery of therapeutic agents, including drugs, genes, proteins, etc., as well as tissue engineering, due to obvious properties such as biocompatibility and their similarity to natural body tissues. Some of these substances have the feature of injectability, which means that the substance is injected into the desired place in the solution state and then turns into the gel, which makes it possible to administer them from a way with a minimal amount of invasion and eliminate the need for surgery to implant pre-formed materials. Gelation can be caused by a stimulus and/or spontaneously. Suppose this induces due to the effect of one or many stimuli. In that case, the material in question is called stimuli-responsive because it responds to the surrounding conditions. In this context, we introduce the different stimuli that cause gelation and investigate the different mechanisms of the transformation of the solution into the gel in them. Also, we study special structures, such as nano gels or nanocomposite gels.

Current advances in engineering meniscal tissues: insights into 3D printing, injectable hydrogels and physical stimulation based strategies

“…For smaller defects injectable hydrogels could be a viable treatment modality due to their shape conformity, elimination of suturing and fixation woes, minimally invasive delivery, facile application, smart stimuli responsive nature and ability to load and deliver growth factors and cells [360][361][362]. Currently reported meniscus regenerative injectable hydrogels, though have excellent capabilities of cellular encapsulation, infiltration, proliferation and differentiation, are limited by their mechanical properties, which is crucial for initial healing stage of meniscus.…”

Hydrogel: a new material for intravesical drug delivery after bladder cancer surgery

“…This feature makes them easy to regulate, as they become a gel at body temperature. 78 The liquid state enables them to be mixed with specific drugs and easily delivered into the bladder through a catheter. The gel state prolongs the time for which the hydrogel mixed with the drug stays in the bladder, ensuring prolonged exposure of the bladder tissue to the drug (Fig.…”

Injectable Poloxamer Hydrogels for Local Cancer Therapy

“…Notwithstanding that thermosensitivity is appealing in the biomedical field, this property depends on concentrated aqueous dispersions of poloxamers [15]. Moreover, to impart biodegradability to the hydrogel, modifications in the polymer structure can be considered [23].…”