Injectable Hyaluronic Acid/Poly(γ-glutamic acid) Hydrogel with Step-by-step Tunable Properties for Soft Tissue Engineering

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.     

聚L-谷氨酸可注射水凝胶的制备及性能

通过活化改性聚L-谷氨酸（PLGA）制备酰肼化PLGA（PLGA-ADH）和3-氨基-1,2-丙二醇改性的PLGA（PLGA-OH）,PLGA-OH经高碘酸钠氧化制得醛基化PLGA（PLGA-CHO）,以PLGA-ADH和PLGA-CHO为前驱体,通过席夫碱交联反应构建了PLGA可注射水凝胶.研究了酰肼化和醛基化改性前后PLGA的结构变化,考察了固含量对水凝胶成胶时间、溶胀行为、机械性能、体外降解性能、药物释放行为及微观形貌等的影响,并进行了初步的细胞培养实验及裸鼠皮下注射成胶实验.结果表明,该PLGA可注射水凝胶在组织工程领域具有良好的应用前景.     

Synthesising injectable molecular self-curing polymer from monomer derived from lignocellulosic oil palm empty fruit bunch biomass: A review on treating Osteoarthritis

Osteoarthritis (OA) is a chronic and irreversible degenerative joint disease that most commonly affects individuals in their forties and fifties worldwide due to the continuously increasing life expectancy. Although joint replacement is an effective remedy for severe end-stage OA, the functional outcomes could be unsatisfactory, while the implants might have a limited lifespan. Due to the drawbacks and limitations of the joint replacement approach, bone Tissue Engineering (TE) is one of the promising bone tissue regeneration technologies that aid in cartilage repair and regeneration and has attracted the attention of experts. The advanced development of biopolymers, in particular biopolymer derived from Oil Palm Empty Fruit Bunch (OPEFB), has been utilised in the fabrication of scaffolds that serve as a crucial component in bone TE. The abundant supply of OPEFB biomass and the increasing trend of converting waste into wealth for environmental sustainability have also provided the opportunity and interest to fully apply biopolymer-derived materials for bone scaffolding and other applications. Therefore, this paper aimed to provide a review of the biopolymers derived from OPEFB for the treatment of OA and other related applications. A brief overview of the biomass sources in Malaysia was presented, followed by a discussion on the chemical compositions and pre-treatment methods of OPEFB by using organosolv pre-treatment and enzymatic hydrolysis for maximum glucose recovery, monomer derived from cellulose OPEFB and synthesizing self-curing polymer scaffold. Additionally, a detailed review of the polymeric biomaterials in bone TE for the fabrication of scaffolds were included in this review. Most importantly, the paper described the potential use of injectable polymeric biomaterials that provide a significant benefit in orthopaedic applications. Overall, this paper provides a perspective on the potential of OPEFB-derived injectable scaffolds as an alternative OA treatment and future bone TE applications.