Preparation Of Injectable Hydrogels Research Articles

Advances in injectable hydrogel: Design, functional regulation, and biomedical applications

AbstractRecently, injectable hydrogels have been considered smart materials and have been widely researched for their use as scaffolds. They resemble the extracellular matrix of native tissue and have the capability for homogeneous mixing with therapeutic agents. It can be implanted into living bodies with minimal invasiveness and usability for irregularly shaped sites. Such unique features make the injectable hydrogels as promising materials in tissue engineering, drug delivery system, and gene/protein delivery. This review article provides a comprehensive overview of the different mechanisms employed in the preparation of injectable hydrogel, as well as a detailed exploration of its applications in the biomedical field. Furthermore, the article highlights the critical importance of developing injectable hydrogels as market‐viable products, highlighting their potential impact in the field of regenerative medicine.

Advanced injectable hydrogels for cartilage tissue engineering.

The rapid development of tissue engineering makes it an effective strategy for repairing cartilage defects. The significant advantages of injectable hydrogels for cartilage injury include the properties of natural extracellular matrix (ECM), good biocompatibility, and strong plasticity to adapt to irregular cartilage defect surfaces. These inherent properties make injectable hydrogels a promising tool for cartilage tissue engineering. This paper reviews the research progress on advanced injectable hydrogels. The cross-linking method and structure of injectable hydrogels are thoroughly discussed. Furthermore, polymers, cells, and stimulators commonly used in the preparation of injectable hydrogels are thoroughly reviewed. Finally, we summarize the research progress of the latest advanced hydrogels for cartilage repair and the future challenges for injectable hydrogels.

FGF가 고정화된 UV경화형 히알루론산 유도체를 이용한 Injectable한 수화젤의 제조

FGF가 고정화된 UV경화형 히알루론산 유도체를 이용한 Injectable한 수화젤의 제조

Preparation of injectable hydrogel with near-infrared light response and photo-controlled drug release

Photo-controlled release hydrogel provides a new strategy for treating tumours. Under the stimulation of external light sources, the ability to release the entrapped drug on time and space on demand has outstanding advantages in improving drug utilisation, optimising treatment, and reducing toxicity and side effects. In this study, a photo-controlled drug delivery system for disulphide cross-linked polyaspartic acid (PASP-SS) hydrogels encapsulating proteinase K (ProK) adsorbed with platinum nanoparticles (PtNPs) was designed. The injectable cysteamine-modified polyaspartic acid (PASP-SH) sol and PtNPs adsorbed by ProK (ProK-PtNPs) as regulatory factors were prepared. Then, ProK-PtNPs and lentinan were dissolved in the sol, and the oxidant was added to the matrix to form the gel in situ quickly after injection. Finally, the degradation of PASP-SS hydrogel by ProK and the controllability of drug release under near-infrared (NIR) light irradiation were elucidated. In vitro degradation of hydrogels and drug release experiments showed that the degradation rate of PASP-SS hydrogel significantly increased and the drug release rate increased significantly under near-infrared radiation. The results of cytotoxicity test showed that PASP-SS, ProK-PtNPs, and lentinan all had more than 90% cell survival rate on NIH3T3, and the lentinan released from the carrier obviously inhibited the proliferation of MCF7. PASP hydrogel has the potential to respond to on-demand light control.

An injectable robust denatured albumin hydrogel formed via double equilibrium reactions

Proteins are ideal raw materials for preparing biomaterials with better biocompatibility and larger elastic range than synthetic polymers. Injectable hydrogels are highly desired for minimal invasive strategies. At present, preparation of injectable hydrogels with good comprehensive properties using natural materials receives more and more attention. In this article, BSA was treated with urea and glutathione to prepare bovine serum albumin hydrogel controlled by two dynamic equilibrium bonds (disulfide and hydrogen bonds). The hydrogen bond equilibrium between urea-protein and protein-protein as well as the exchange reaction equilibrium between thiol-disulfide bonds in the system not only facilitated to enhance the mechanical properties, but also to reduce the gelation time to 5 min. Moreover, this novel albumin hydrogel was proved to be of good biocompatibility. Therefore, the albumin hydrogels in this article were injectable within the physiological range and shown low cytotoxicity, good machanical property ( storage modulus could be greater than 10 kPa and compressive stress could reach 0.2 MPa) and good injectability, which exhibited promising prospect.

Preparation of injectable hydrogels from temperature and pH responsive grafted chitosan with tuned gelation temperature suitable for tumor acidic environment

In this present work, stimuli responsive polymers that can respond to the temperature and pH of the environment were prepared. A series of temperature responsive diblock copolymers based on poly(ethylene glycol) methyl ether (mPEG) and ε-caprolactone (CL) were synthesized. Subsequently, the diblock copolymers were grafted onto chitosan, a pH responsive biopolymer. These chitosan-graft-(mPEG-block-PCL) (chitosan-g-(mPEG-b-PCL)) graft copolymers were structurally characterized by 1H NMR and FTIR and their sol-gel phase transitions were analyzed by the test tube inversion method as well as dynamic rheological measurements. These chitosan-g-(mPEG-b-PCL) graft copolymers demonstrated tunable temperature and pH responsive sol-gel phase transitions that correspond well with body temperature and pH of acidic tumor microenvironments. Gelation temperature (Tgel) decreased with increasing pH of the system, increasing PCL composition in the diblock copolymers, increasing solution concentration and decreasing grafting content of the diblock copolymers on chitosan. The graft copolymer hydrogels successfully showed the sustained release of both doxorubicin and curcumin for up to 2 weeks. The designed system was based on chitosan-g-(mPEG-b-PCL) graft copolymers, of which chitosan showed pH responsive properties and mPEG-b-PCL acted as a temperature sensitive moiety. In addition, mPEG and PCL are recognized as biocompatible polymers and chitosan has been engaged in various pharmaceutical research. Thus, this system could be considered an alternative choice for drug delivery applications.

Chitosan-based hydrogels: Preparation, properties and applications

Chitosan (CS), the second most plentiful natural polysaccharide next to cellulose, has valuable characteristics including biocompatibility, nontoxicity and biodegradability. CS is broken down in the human body to innocuous products (amino sugars). Hydrogels are polymeric materials with three dimensional networks retaining a huge quantity of water within their structures which are of great interest in biomedical/environmental applications. Usually, injectable hydrogels have functional groups which are sensitive to pH, temperature or irradiation stimuli. Injectable scaffolds can be formed in situ through stimuli-responsive effect and they can overcome the drawback of traditional scaffolds which require surgery in order to be placed on the desired tissue. The antibacterial/antifungal activities of chitosan-based hydrogels and their applications in controlled drug delivery/release systems, tissue engineering, preparation of injectable hydrogels and water treatment (removal of heavy/toxic metals and dyes) will be described. Moreover, the molecular dynamics (MD) simulation were performed on the delivery of the anticancer chlorambucil (CB) drug using three silica filled polymeric nanocomposites based on chitosan (CS), polylactic acid (PLA) and polyethylene glycol (PEG) and it was illustrated that among three drug delivery systems (DDSs), the CS nanocomposite was the most efficient DDS due to the lowest drug diffusion was measured for the CS system that could lead to the most sustained/controlled drug delivery.

An overview of injectable polymeric hydrogels for tissue engineering

The desire and need to minimize traditional open surgeries is gearing up as it could reduce the healthcare expenses and improve the recovery time for the patients. Minimal invasive procedures using endoscopes, catheters and needles have been developed considerably in the last few decades. In the field of tissue engineering and regenerative medicine, there is a need for advancement over the conventional scaffolds and pre-formed hydrogels. In this scenario, injectable hydrogels have gained wider appreciation among the researchers, as they can be used in minimally invasive surgical procedures. Injectable gels with their ease of handling, complete filling of the defect area and good permeability have emerged as promising biomaterials. The system can effectively deliver a wide array of therapeutic agents like drugs, growth factors, fillers and even cells. This review provides an overview of the recent trends in the preparation of injectable hydrogels, along with key factors to be kept in balance for designing an effective injectable hydrogel system. Further, we have summarized the application of injectable hydrogels in adipose, bone, cartilage, intervertebral discs and muscle tissue engineering.

Preparation of thermosensitive hydrogels by means of tandem physical and chemical crosslinking

The tandem physical and chemical crosslinking was used to prepare injectable hydrogels. First, the terpolymers with diene groups were synthesized by the free radical copolymerization of N-isopropylacrylamide (NIPA), N,N-dimethylacrylamide (DMA) and furfuryl methacrylate (FM). Second, dienophile-functionalized terpolymers were obtained from the terpolymers of NIPA, DMA, and 2-hydroxyethyl methacrylate (HEMA) and N-maleoyl alanine (AMI) by a coupling reaction under N,N′-dicyclohexylcarbodiimide (DCC). When the screened diene-functionalized terpolymer and dienophile-functionalized terpolymer were dissolved separately in water and mixed, physically cross-linked hydrogels formed rapidly within 10 s at 37 °C. Subsequently, the physically crosslinked hydrogels could change gradually into chemically cross-linked hydrogels by a Diels-Alder reaction and the mechanical strength of the hydrogels could be improved. The swelling behavior study suggests that the hydrogels possess thermosensitivity and good reproducibility at different temperatures. The strategy described, i.e. incorporating the advantages of physically crosslinked hydrogels and chemically crosslinked hydrogels, has potential applications in the preparation of injectable hydrogels. Open image in new window