Poly(vinyl alcohol)–hyaluronic acid injectable hydrogel as a nucleus pulposus substitute candidate

Based on the Global Burden of Disease (GBD) study, low back pain is the top 10 highest prevalence diseases in the world. As many as 30%-80% of cases are induced by herniated nucleus pulposus (HNP). HNP is a protrusion of the nucleus pulposus (NP) caused by the rupture of the annulus fibrosus. Injectable hydrogel as an NP substitute is an alternative HNP treatment through hydrating and restoring disc thickness with minimally invasive surgery. A poly(vinyl alcohol)-hyaluronic acid hydrogel was developed as an injectable material for the treatment of HNP. Poly(vinyl alcohol) or PVA has good mechanical properties. While hyaluronic acid (HA) is the main component of glycosaminoglycans found in NP. Tween-80 was used as a surfactant to improve the homogeneity and dispersion of the polymer mixture synthetized using the freeze-thawing method with variations of PVA-HA ratio about 7-0, 7-0.3, 7-0.6, and 7-0.9, in % (w/v). According to the Fourier transform infrared spectroscopy (FTIR) spectrum result, our samples showed the -CO-O group of PVA-HA and Tween-80. Thus, the viscosity of the sample increases with increasing HA content. The addition of HA concentration increase sample swelling ratio, degradation rate and cell viability. The overall sample has excellent compressive strength and injectability close to 100%. The entire sample also can occupy the details of the agarose mold with good intact. We also found that the samples can be set in a shorter time along with the addition of HA content.