Tianlong Huang

Effect of Chemical Cross-linking on Properties of Gelatin/Hyaluronic Acid Composite Hydrogels

A composite hydrogel was fabricated by introducing hyaluronic acid (HA) into gelatin (Gel) using 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide (EDC) as a cross-linker. The effects of cross-linking, including cross-linker content and cross-linking time, on the morphology, swelling ratio, compressive strength and cytotoxicity in vitro of the Gel/HA hydrogel were investigated. The results showed that the pore size of the Gel/HA hydrogel decreased with increasing cross-linker content. Further, the swelling ratio of the Gel/HA hydrogel also decreased with increasing cross-linker content and cross-linking time. However, the compressive strength increased with increasing EDC content and cross-linking time. The hydrogel extracts with various contents of EDC were not toxic, due to easy removal of excess EDC by washing with dilute acid or water.

Fabrication and Physical Properties of Gelatin/Sodium Alginate/Hyaluronic Acid Composite Wound Dressing Hydrogel

Gelatin (Gel), sodium alginate (SA) and hyaluronic acid (HA) based various hydrogels for biomedical applications were prepared by freezing-drying method using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) as a crosslinker. The physical properties including morphology, water vapor transmission rate and hydrophilicity were investigated. The result showed the Gel/SA/HA composite hydrogels were successfully crosslinked by the crosslinking agent. All the Gel/SA/HA composite hydrogels with different compositions had highly homogeneous and interconnected pores, and the compositions had no significant effect on the surface and cross-section morphologies of the Gel/SA/HA hydrogels. The incorporation of sodium alginate enhanced the water vapor transmission capacity of the hydrogel; however, there were no significant differences between the water vapor transmission rates of all the Gel/SA/HA hydrogels. Gelatin had a low hydrophilic behavior, while sodium alginate exhibited relatively high hydrophilic behavior. The results indicate that the Gel/SA/HA hydrogel cross-linked via EDC is a potential wound dressing material capable of the adequate provision of moist environment for comfortable wound healing.

Degradation behaviour and biological properties of gelatin/hyaluronic acid composite scaffolds

Abstract Hydrogels, based on natural polymers, are gaining attention as possible cell scaffolding materials for the regeneration of a variety of tissues. In this work, gelatin (Gel) and hyaluronic acid (HA) were used to fabricate novel scaffold materials using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linker. The degradation behaviours of Gel/HA scaffolds in phosphate buffered saline (PBS) and PBS solution containing lysozyme were investigated respectively. The biological properties including haemolytic activity and acute systemic toxicity were also studied. The results showed that the scaffold had an interconnected pore structure with an average pore size of about 100–500 μm. The degradation of Gel/HA scaffolds in PBS solution containing lysozyme was faster than that in PBS solution. The haemolytic ratio of 0·340–0·781% indicated that the Gel/HA scaffolds have a good blood compatibility. The acute systemic toxicity test showed that Gel/HA extracts have no acute systemic toxicity.

Characterization of Biocompatible Scaffolds Based on Gelatin and Hyaluronic Acid for Fibroblasts Culture

Gelatin/hyaluronic acid (Gel/HA) scaffolds were prepared by using the freeze-drying method after crosslinking with 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide (EDC). The porous structure was characterized by scanning electron microscopy (SEM), and the wettability of Gel/HA film was also studied by measuring their contact angle. The biological behaviour of the scaffolds was analyzed by studying the cell behaviour using a fibroblast cell line and standard biological MTT test. The results showed that the scaffold had an inter-connected pore structure with a sufficient pore size for use as a support for the growth of fibroblasts. The contact angle decreased with increasing HA content, whereas the cell attachment and proliferation improved with decreasing HA content. Confocal laser scanning microscopy (CLSM) demonstrated a normal cell distribution and proliferation on the porous Gel/HA scaffolds.

Fabrication and characterisation of gelatin-hyaluronic acid/nanobioactive glass hybrid scaffolds for tissue engineering

Abstract Nanobioactive glass (NBG) particles were synthesised via sol–gel method and characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The new composite biomaterial based on gelatin (Gel) conjugated with hyaluronic acid (HA) and NBG in the ternary SiO2–CaO–P2O5 system was prepared through freeze drying method. The composite scaffold was characterised by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermal analyses. Mechanical properties and swelling behaviour of this composite are compared with properties of Gel-HA/NBG composite of similar material without NBG. The TEM results indicated that the prepared NBG particle size was ∼100 nm. The SEM studies showed that the NBG were homogenously distributed within the Gel/HA matrix and the composite scaffolds showed interconnected pores with a size varied from 50 to 200 μm. The Gel-HA/NBG composite scaffold showed higher compressive strength and better stability than the Gel/HA scaffold. These results indicate that composite scaffolds developed using NBG disseminated Gel/HA matrix as potential scaffolds for tissue engineering applications.

Preparation and Properties of Novel Maleated Poly (D, L-lactide-co-glycolide) Porous Scaffolds for Tissue Engineering

ABSTRACT Three-dimensional biodegradable porous scaffolds play an important role in tissue engineering. A new polymer based on maleated poly(lactic-co-glycolic acid) (MPLGA) was synthesized using direct melt copolymerization from maleic anhydride (MAH), D, L-lactide, and glycolide monomers. MPLGA porous biodegradable scaffolds were prepared by a solution-casting/salt-leaching method. The effects of content and size of the NaHCO3 porogen on the compressive strength of the MPLGA scaffolds were investigated, and the effect of content of the porogen on the porosity of the MPLGA scaffolds was also studied. The results indicated that MAH was grafted onto PLGA successfully and MPLGA scaffolds with interconnective and open pore structure were obtained. Increasing content of NaHCO3 porogen resulted in an increase of porosity and decrease of the compressive strength of the MPLGA scaffolds with the compressive strength of the scaffolds also decreasing with increasing porogen size.

Synthesis, characterization, and degradation behaviors of poly(D,L-lactide-co-glycolide) modified by maleic anhydride and ethanediamine

ABSTRACT In order to improve hydrophilicity and settle the acidity in hydrolysis, a novel ethanediamine (EDA) and maleic anhydride (MAH) modified poly(D,L-lactide-co-glycolide) (PLGA) polymer (EMPLGA) was synthesized. Fourier Transform Infrared Spectrometer (FTIR), Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (1HNMR), titration and the water contact angles were employed to characterize the synthesized polymer. The effects of various polymerization conditions on weight average molecular mass (Mw), polydispersity index (PDI) and anhydride content of MPLGA were investigated. The degradation behaviors of PLGA, MPLA and EMPLGA were also studied by observation of the changes of the pH value of incubation medium, molecular weight and weight loss ratio for a time interval of 25 days in-vitro, respectively. The results showed that MPLGA with high anhydride content was successfully obtained by directly ring-opening polymerization and ethanediamine was further grafted onto MPLGA, and there is almost unchanged in Mw between MPLGA and EMPLGA polymers. The introduction of anhydride and amino groups improved the hydrophilicity of PLGA. A uniform degradation of EMPLGA was observed in comparison with an acidity-induced auto-accelerating degradation featured by PLGA and MPLGA. The results revealed that the introduction of ethanediamine into PLGA has weakened or neutralized the acidity of PLGA degradation products.

Influence of Nano-Bioactive Glass (NBG) Content on Properties of Gelatin-Hyaluronic Acid/NBG Composite Scaffolds

The development of three-dimensional (3-D) scaffolds with highly open porous structure is one of the most important issues in tissue engineering. A novel nanocomposite scaffold of gelatin (Gel), hyaluronic acid (HA), and nano-bioactive glass (NBG) was prepared by blending NBG with a Gel and HA solution followed by lyophilization. The effects of NBG content on the properties of the Gel-HA/NBG composite scaffolds, including the morphologies, porosity, compressive strength, swelling behavior, cell viability and alkaline phosphatase (ALP) activity, were investigated. Porous composite scaffolds with interconnected pores were obtained and the pores became cylindrical with increasing NBG content. The porosity percent and swelling ability decreased with increasing NBG content; however, the compressive strength, cell viability and ALP activity were enhanced. All the results showed the addition of NBG particles can improve the physicochemical and biological properties and the Gel-HA/NBG composite scaffolds exhibited good potential for tissue engineering applications.

Biological Assessment In-Vivo of Gel-HA Scaffold Materials Containing Nano-Bioactive Glass for Tissue Engineering

To evaluate the biological safety of the composite materials based on gelatin (Gel), hyaluronic acid (HA), and nano-bioactive glass (NBG), which has a potential application in tissue engineering, the in-vivo biological properties were investigated by hemolysis behavior, micronucleus, skin irritation and acute toxicity test. Scanning electron microscopy (SEM) morphology demonstrated that the Gel-HA/NBG composite scaffolds had interconnected pores with mean diameters of 50–500 μm. The hemolysis test suggested that the Gel-HA/NBG composite scaffold, with a hemolysis ratio of 1.11%, showed no obvious hemolysis reaction. The micronucleus frequency of the Gel-HA/NBG was (3.1 ± 0.52) %; this indicated that it shows no genotoxic effect. The skin irritation result showed no systemic signs of toxicity in the integrity skin of the animals. The Gel-HA/NBG scaffolds showed no acute systemic toxicity and the liver, heart, lung, and kidney samples also showed no remarkable change in the morphology. Therefore, Gel-HA/NBG composite scaffold would be a suitable candidate of biomedical materials for tissue engineering.

Evaluation of Biological Properties In-Vivo of Poly(L-Lactide-Coglycolide) Composites Containing Bioactive Glass

To evaluate the biological safety of composite materials based on poly(L-lactide-co-glycolide) (PLGA) and bioactive glass (BG), which have a potential application in tissue engineering, the in-vivo biological properties were investigated by applying the micronucleus test, acute systemic toxicity test, haemolytic test and pyrogen measurement. The results indicated that the PLGA/BG composite showed no genetic toxicity; there was no toxicosis or death observed in the acute systemic toxicity test. The haemolytic test suggested that the PLGA/BG composite, with a haemolytic index of 0.281%, did not have an obvious haemolytic reaction. In addition, the PLGA/BG composite materials showed no pyrogen reaction. Therefore, PLGA/BG composite materials could be promising candidate biomedical materials for bone tissue engineering.