Injectable hydrogels as an important class of biomaterials have gained much attention in tissue engineering. However, their crosslinking degree is difficult to be controlled after being injected into body. As we all know, the crosslinking degree strongly influences the physicochemical properties of hydrogels. Therefore, developing an injectable hydrogel with tunable crosslinking degree in vivo is important for tissue engineering. Herein, we present a dual crosslinking strategy to prepare injectable hydrogels with step-by-step tunable crosslinking degree using Schiff base reaction and photopolymerization. The developed hyaluronic acid/poly(γ-glutamic acid)(HA/γ-PGA) hydrogels exhibit step-bystep tunable swelling behavior, enzymatic degradation behavior and mechanical properties. Mechanical performance tests show that the storage moduli of HA/γ-PGA hydrogels are all less than 2000 Pa and the compressive moduli are in kilopascal, which have a good match with soft tissue. In addition, NIH 3 T3 cells encapsulated in HA/γ-PGA hydrogel exhibit a high cell viability, indicating a good cytocompatibility of HA/γ-PGA hydrogel.Therefore, the developed HA/γ-PGA hydrogel as an injectable biomaterial has a good potential in soft tissue engineering. 相似文献
Biocompatible hydrogels are of high interest as a class of biomaterials for tissue engineering, regenerative medicine, and controlled drug delivery. These materials offer three-dimensional scaffolds to support the growth of cells and development of hierarchical tissue structures. Fmoc-peptides were previously demonstrated as attractive building blocks for biocompatible hydrogels. Here, we further investigate the biophysical properties of Fmoc-peptide-based hydrogels for medical applications. We describe the structural and thermal properties of these Fmoc-peptides, as well as their self-assembly process. Additionally, we study the role of interactions between aromatic moieties in the self-assembly process and on the physical and structural properties of the hydrogels. 相似文献
Injectable hydrogels are ideal biomaterials for delivering cells, growth factors and drugs specifically to localized lesions and subsequent controlled release. Many factors can affect the efficacy of injectable hydrogels. To avoid potential damage to encapsulated cells or drugs, injectable hydrogels should be highly dynamic so that they can undergo shear-thinning at low strain rates and rapidly reform after injection. However, dynamic hydrogels are often mechanically weak, leading to the leakage of encapsulated cells or drugs. Here we demonstrated a convenient method to improve the mechanical strength without jeopardizing the dynamic properties of hydrogels by using metal ion-peptide crosslinkers containing multiple metal ion-ligand bonds. We showed that the dynamic properties of the hydrogels correlated with the intrinsic dynamics of the metal-ligand bonds and were not affected by the formation of multivalent binding. Yet, the mechanical stability of the hydrogels was significantly improved due to the increased thermodynamic stability of the crosslinkers. We further showed that the drug release rates were slowed down by the formation of multivalent crosslinkers. Our results highlight the importance of ligand valency to the mechanical response of hydrogels and provide a universal route to rationally tune the dynamic and mechanical properties of injectable hydrogels. 相似文献
Injectable hydrogel is a kind of in situ gelling system but has its specificity on the process procedure, which requires a better control of gelation kinetics. Hydrogels with injectability under mild condition are preferred in the field of biomedicine, especially for drug delivery and tissue engineering, because of the favorable carrier property in three-dimension, biocompatibility, low invasive and adaptable shape for administration. Despite the advantages, the development of injectable hydrogels may also face some challenges to meet the various clinical requirements. In this review, we provide a brief summary on the recent progresses on the design, synthesis and evaluation of injectable hydrogels towards biomedical applications. 相似文献
Injectable hydrogels have been commonly used as drug‐delivery vehicles and tried in tissue engineering. Injectable self‐healing hydrogels have great advantage over traditional injectable hydrogels because they can be injected as a liquid and then rapidly form bulk gels in situ at the target site under physiological conditions. This study develops an injectable thermosensitive self‐healing hydrogel based on chain‐extended F127 (PEO90‐PPO65‐PEO90) multi‐block copolymer (m‐F127). The rapid sol–gel transition ability under body temperature allows it to be used as injectable hydrogel and the self‐healing property allows it to withstand repeated deformation and quickly recover its mechanical properties and structure through the dynamic covalent bonds. It is hoped that the novel strategy and the fascinating properties of the hydrogel as presented here will provide new opportunities with regard to the design and practical application of injectable self‐healing hydrogels.
Supramolecular hydrogels are a class of self‐assembled network structures formed via non‐covalent interactions of the hydrogelators. These hydrogels capable of responding to external stimuli are considered to be smart materials due to their ability to undergo sol–gel and/or gel–sol transition upon subtle changes in their surroundings. Such stimuli‐responsive hydrogels are intriguing biomaterials with applications in tissue engineering, delivery of cells and drugs, modulating tissue environment to promote innate tissue repair, and imaging for medical diagnostics among others. This review summarizes the recent developments in stimuli‐responsive supramolecular hydrogels and their potential applications in regenerative medicine. Specifically, various structural aspects of supramolecular hydrogelators involved in self‐assembly, the role of external stimuli in tuning/controlling their phase transitions, and how these functions could be harnessed to advance applications in regenerative medicine are focused on. Finally, the key challenges and future prospects for these versatile materials are briefly described. 相似文献
Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found a variety of biomedical applications, such as drug delivery, cell encapsulation, and tissue engineering. This critical review systematically summarizes the recent progresses on biodegradable and injectable hydrogels fabricated from natural polymers (chitosan, hyaluronic acid, alginates, gelatin, heparin, chondroitin sulfate, etc.) and biodegradable synthetic polymers (polypeptides, polyesters, polyphosphazenes, etc.). The review includes the novel naturally based hydrogels with high potential for biomedical applications developed in the past five years which integrate the excellent biocompatibility of natural polymers/synthetic polypeptides with structural controllability via chemical modification. The gelation and biodegradation which are two key factors to affect the cell fate or drug delivery are highlighted. A brief outlook on the future of injectable and biodegradable hydrogels is also presented (326 references). 相似文献
In light of the limited efficacy of current treatments for cardiac regeneration, tissue engineering approaches have been explored for their potential to provide mechanical support to injured cardiac tissues, deliver cardio‐protective molecules, and improve cell‐based therapeutic techniques. Injectable hydrogels are a particularly appealing system as they hold promise as a minimally invasive therapeutic approach. Moreover, injectable acellular alginate‐based hydrogels have been tested clinically in patients with myocardial infarction (MI) and show preservation of the left ventricular (LV) indices and left ventricular ejection fraction (LVEF). This review provides an overview of recent developments that have occurred in the design and engineering of various injectable hydrogel systems for cardiac tissue engineering efforts, including a comparison of natural versus synthetic systems with emphasis on the ideal characteristics for biomimetic cardiac materials. 相似文献