Poly(vinyl alcohol) is a non-toxic, biosynthetic polymer and biocompatible polymer that has the ability to form hydrogels either via chemical or physical crosslinking. Whilst chemical crosslinking provides greater control on the properties of the resultant hydrogel, physically crosslinked hydrogels or blends with other biocompatible polymers are more suited for biomedical applications. In this paper we report a systematic study on the effect of varying concentrations of PVA, physical methods of crosslinking, and PVA-gelatin and PVA-PVP blends on the physical and mechanical properties of the hydrogels.

Summary A retrospective population-based survey in the Republic of Botswana determined the incidence of fractures at the hip over 3 years. The estimated number of such fractures nationwide for 2020 was 103 and is predicted to increase. Objective This article describes the epidemiology of hip fractures in the Republic of Botswana. Methods A retrospective patient chart review was conducted to identify from hospital registers the number of patients diagnosed with hip fracture in 2009, 2010, and 2011. Age- and sex-specific incidence of hip fracture was determined from which lifetime probabilities and future projections for hip fracture were calculated. Results The incidence of hip fracture was low and comparable to rates reported from Tunisia. The remaining lifetime risk of hip fracture at the age of 50 years in men and women was 1.4 and 1.1%, respectively. The incidence of hip fracture suggested that the estimated number of hip fractures nationwide in persons over the age of 50 years for 2020 was 103 and is predicted to increase by more than threefold to 372 in 2050. Conclusion The hip fracture rates can be used for healthcare planning. Additionally, these data can be used to create a FRAX model to help guide decisions about treatment.

The incidence of degenerative diseases and the ageing population have added to the growing demand for bone grafts. Although autologous bone continues to be the gold standard, limited yield and potential morbidity of the donor site pose considerable challenges. Currently, clinically used synthetic grafts based on calcium phosphates are mechanically brittle and not compliant hence composite scaffolds are expected to be provide viable solutions. In this study we report composites of calcium meta phosphate-poly (vinyl alcohol) with tunable mechanical properties, low swelling and excellent biocompatibility. The elastomeric nature of the composites resist brittle fracture and the scaffolds can be easily shaped to the bone defect by the surgeon. Testing on bone plug shaped specimens of the scaffolds, exhibited superior mechanical properties compared to currently commercially available bone plugs with additional advantages being the ability to increase porosity without compromising properties in compression and degree of swelling, which make these composites promising synthetic alternatives for bone grafts and bone tissue engineering.

Inspired by the double network hydrogel systems we report the formulation of dual networks, which expands the repertoire of this class of materials for potential biomedical applications. The tough dual network hydrogels were designed through sequential interpenetrating polymer formation, applying green chemistry and low-cost methods, devoid of any initiator-activator complexes that may pose risks in biomedical applications. The dual networks were synthesized in two steps, firstly the water soluble poly(vinyl alcohol) was subjected to cryogelation that formed the first network, which was then expanded by intrusion of a dilute solution of sodium alginate and complexed with a solution of calcium chloride under ambient conditions and further freeze-thawed. These hydrogels are flexible, ductile and porous with the ability to absorb and retain fluids as well as possess the versatility to easily incorporate biological molecules/drugs/antibiotics to be applied in tissue matrices or drug delivery systems. The dual network hydrogels can be tailored to have varying mechanical properties, shapes, size, thickness and particularly can be made physically porous if required, to suit the users intended application.