Siliang He

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.

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.

Influences of Molecular Weight and Content of Polyethylene Glycol on Morphology and Size of Nano-Bioactive Glass

Nano-bioactive glass (NBG) was prepared via sol-gel method and freeze-dried technique using polyethylene glycol (PEG) as templates. The influences of molecular weight and content of polyethylene glycol on the morphology and the size NBG particles were investigated. The optimal sintering temperature of NBG was determined by using thermal gravimetric (TG) and differential thermal analysis (DTA), and the NBG particles were characterized by Fourier-transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The XRD pattern of NBG sintered at 650°C in air confirmed that the calcined glass existed in amorphous state. The results indicated that the PEG molecular weight and PEG content have obvious effects on the morphology and size of the NBG particles. The size of NBG particle prepared with PEG-200 was beyond 1μm and the aggregation was obvious. The size of obtained NBG particle with PEG-10000 was between 50 nm and 80 nm, with a hollow spherical shape; while the morphology of the NBG with PEG-20000 was needle-shaped, with an average width of 20 nm and length of 100 nm. The particle size of the NBG particles decreased with the increase of PEG concentration.

Assessment of biological properties of collagen/hyaluronic acid composite scaffolds containing nanobioactive glass

In the present work, a nanocomposite scaffold was prepared on the basis of collagen, hyaluronic acid (HA) and nanobioactive glass (NBAG) by the freeze drying method for the application to tissue engineering scaffold materials. The biological property assays, including von Kossa staining, tetracycline staining, hemolysis, platelet adhesion test, pyrogen tests and acute toxicity test, were performed according to the requirements of ISO 10993 standards to evaluate its performance as applicable tissue engineering. The results indicated that the collagen-HA/NBAG scaffold possessed a homogeneous morphology and interconnected pore structure, with pore sizes ranging from 50 to 500 μm in diameter. Examination of the hemolytic potential showed that the nanocomposite scaffolds were non-hemolytic in nature and showed blood compatibility. The platelet adhesion tests showed that the collagen-HA/NBAG material had an excellent anticoagulation property. The collagen-HA/NBAG scaffolds showed no acute systemic toxicity or pyrogen reaction. The results of von Kossa and tetracycline stainings indicated that the NBAG can promote fibroblastic differentiation and improve the mineral deposition of the collagen/HA. Therefore, the collagen-HA/NBAG composite materials would be a promising candidate of biomedical materials for tissue engineering.

Morphology and size control of gelatin/hyaluronic acid composite microsphere for drug delivery

Composite microspheres based on gelatin (Gel) and hyaluronic acid (HA) were prepared by an emulsion–coagulation method with glutaraldehyde as a crosslinker. The influences of stirring speed, crosslinker concentration, HA content and water/oil ratio on the particle size and surface morphology were investigated. The Fourier transform infrared spectra characterisation indicated that Gel and HA were crosslinked successfully by the glutaraldehyde. The in vitro release behaviours of 5-fluorouracil (5-FU) from Gel/HA microspheres were also studied. The results showed that the adhesion and agglomeration phenomena were apparent when the HA content reached 10.0 wt-%. The particle diameter of the microspheres decreased greatly with increasing stirring speed; however, the adhesion of smaller microspheres could be observed when the stirring speed reached 800 rev min− 1. The effect of crosslinker concentration on the particle size was not significant, but the dispersion degree of the Gel/HA microspheres decreased with decreasing crosslinker content. The particle size of the microspheres gradually became uniform with the increase of the water/oil ratios. The dispersion and surface smoothness level could be improved by optimising the experimental conditions. The cumulative drug release of 5-FU from the microspheres decreased with increasing glutaraldehyde content. The results of 5-FU release kinetics from Gel/HA microspheres indicated Fickian diffusion.