Natural Sources and Applications of Demineralized Bone Matrix in the Field of Bone and Cartilage Tissue Engineering.

Demineralized bone matrix (DBM) is one of the most widely used materials for bone repair. Recently, different strategies in tissue engineering have been used to improve preparation of biomaterials from natural sources suitable for the use in bone regeneration. However, the application of DBM in tissue engineering is still a challenge, because the mechanical properties which are essential to bear tensile and load and the risk of transmission of disease by donor are still a matter of homework. A solution to this problem is to blend natural and synthetic polymers to complement defects and make them ideal biomaterials. An ideal biomaterial improves survival, adhesion, proliferation, induction, and differentiation of cells in the biomaterial after in vivo transplantation. In this review, we will look at the study of DBM made of natural and synthetic materials giving a direction for future research.

Preparation and characterization of an injectable dexamethasone-cyclodextrin complexes-loaded gellan gum hydrogel for cartilage tissue engineering.

In this study, 6-(6-aminohexyl) amino-6-deoxy-ß-cyclodextrin-gellan gum complex hydrogel (HCD-GG) was developed to enhance the affinity of anti-inflammatory drug dexamethasone (Dx), improve chondrogenesis, and decrease the inflammatory response. The modified chemical structure was confirmed by NMR and FTIR. Mechanical and physicochemical properties were characterized by performing viscosity study, compression test, injection force test, swelling kinetic, weight loss, and morphological study. The release profile of the drug-loaded hydrogels was analyzed to confirm the affinity of the hydrophobic drugs and the matrix and characterize cumulative release. In vitro test was carried out with MTT assay, live/dead staining, glycosaminoglycan (GAGs) content, double-stranded DNA (dsDNA) content, morphological analysis, histology, and gene expression. In vivo experiment was conducted by implanting the samples under a subcutaneous area of SPD rat and cartilage defected rabbit model. The results displayed successfully synthesized HCD-GG. The gelation temperature of the modified hydrogels was decreased while the mechanical property was improved when the drug was loaded in the modified hydrogel. Swelling and degradation kinetics resulted in a higher level compared to the pristine GG but was a sufficient level to support drugs and cells. The affinity and release rate of the drug was higher in the HCD-GG group which shows an improved drug delivery system of the GG-based material. The microenvironment provided a suitable environment for cells to grow. Also, chondrogenesis was affected by the existence of Dx and microenvironment, resulting in higher expression levels of cartilage-related genes while the expression of the inflammation mediators decreased when the Dx was loaded. In vivo study showed an improved anti-inflammatory response in the drug-loaded hydrogel. Furthermore, the cartilage defected rabbit model showed an enhanced regenerative effect when the Dx@HCD-GG was implanted. These results suggest that HCD-GG and Dx@HCD-GG have the potential for cartilage regeneration along with multiple applications in tissue engineering and regenerative medicine.

Development of fluorescein isothiocyanate conjugated gellan gum for application of bioimaging for biomedical application.

Herein, gellan gum (GG), a nature-derived polysaccharide, was applied to combine fluorescein isothiocyanate (FITC) to fabricate a bio-imaging material. The synthesis process of the FITC grafted GG (GG-F) and manufacturing method of GG-F scaffolds are presented. Chemical, physicochemical, and mechanical properties were characterized. In vitro study and in vivo study by implanting the GG-F scaffolds under the subcutaneous area of the nude mice were carried out to verify biocompatibility and safety of the material. The emission of the FITC was confirmed with high-resolution confocal laser scanning microscope (SR CLMS) and fluorescence in vivo imaging (FOBI). The results exhibited well-synthesized GG-F and the manufactured GG-F scaffolds showed similar property of GG scaffolds which confirms that the chemical modification does not affect the property of GG scaffolds. The in vitro and in vivo study exhibited biocompatibility of the GG-F material. Overall, the properly blended GG-F in GG did not influence the characteristics of the pristine GG except for the chemical property. Therefore, the GG-F can be applied for the future analysis in verifying the mechanism of GG characters and can be a promising candidate for bio-imaging.

Development of a Safe Syringe Disposal System Moving towards Automated Syringe Data Collection.

OBJECTIVES: An automatic needle destroyer (ANDY) was developed to prevent needlestick injuries, and usability tests were conducted in several hospitals. The addition of extra features to the ANDY is in progress, such as data collection and automatic identification of used syringes. Thus, this report describes how the ANDY can be used to track the data of used syringes. METHODS: The motor torque required for barrel separation differs according to syringe diameters. By monitoring the electric current which is consumed for the motor torque, the type of syringe can be identified. Twelve prototypes were produced, and five usability tests were conducted in hospitals. RESULTS: After use, a syringe is inserted into the proposed device, and the needle portion is then cut and separated from the syringe body (barrel) and discarded. The needles are collected in a sharps container for hygienic disposal, and the barrel is dropped into a general medical waste container. CONCLUSIONS: The ANDY can be used to track the syringe used for each patient. The barcode can be read while the syringe rotates in the main body of the ANDY with a built-in omnidirectional scanner. Collection of information during syringe disposal can facilitate stock management. This system could also be extended to other types of consumable medical devices, although it would still be a challenge to differentiate each medical device.

Evaluation of cartilage regeneration of chondrocyte encapsulated gellan gum-based hyaluronic acid blended hydrogel.

Hydrogels have shown to be advantageous in supporting damaged cartilage because of its analogous to the extracellular matrix (ECM) of cartilage tissue. However, problems such as infection and inflammation are still a challenge to be solved. In terms of tissue engineering, natural materials are more advantageous than synthetic materials in biocompatibility and biodegradability status. Herein, physically blended nature-derived gellan gum (GG) hydrogel and hyaluronic acid (HA) hydrogel is suggested as a one of solution for cartilage tissue engineering material. The purpose of this study is to determine the effect of GG/HA hydrogel in vitro and in vivo. The chemical and mechanical properties were measured to confirm the compatibility of hydrogels for cartilage tissue engineering. The viability, proliferation, morphology, and gene expression of chondrocytes encapsulated in hydrogels were examined in vitro. Furthermore, the beneficial effect of the blended hydrogel was confirmed by performing the in vivo experiment. The chemical properties of hydrogels confirmed the well physically blended hydrogels. The mechanical studies of hydrogels displayed that as the content of HA increases, the swelling ratio was higher, compressive strength decreased and degradation was faster. Therefore, to use the hydrogel of GG and HA network, the proper amount must be blended. The in vitro study of chondrocytes encapsulated GG/HA hydrogel showed that the proper amount of HA enhanced the cell growth, attachment, and gene expression. The in vivo examination verified the advantageous effect of GG/HA hydrogel. Overall results demonstrate that GG/HA hydrogel is suitable for culturing chondrocyte and can be further applied for the treatment of cartilage defects.