Nanofibrillated cellulose composite hydrogel for the replacement of the nucleus pulposus

Abstract

a b s t r a c tThe swelling and compressive mechanical behavior as well as the morphology and biocompatibility of composite hydrogels based on Tween Ò 20 trimethacrylate (T3), N-vinyl-2-pyrrolidone (NVP) and nanofibrillated cellulose (NFC) were assessed in the present study. The chemical structure of T3 was verified by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance, and the degree of substitution was found to be around 3. Swelling ratios of neat hydrogels composed of different concentrations of T3 and NVP were found to range from 1.5 to 5.7 with decreasing concentration of T3. Various concentrations of cellulose nanofibrils (0.2-1.6 wt.%) were then used to produce composite hydrogels that showed lower swelling ratios than neat ones for a given T3 concentration. Neat and composite hydrogels exhibited a typical nonlinear response under compression. All composite hydrogels showed an increase in elastic modulus compared to neat hydrogel of about 3-to 8-fold, reaching 18 kPa at 0% strain and 62 kPa at 20% strain for the hydrogel with the highest NFC content. All hydrogels presented a porous and homogeneous structure, with interconnected pore cells of around 100 nm in diameter. The hydrogels are biocompatible. The results of this study demonstrate that composite hydrogels reinforced with NFC may be viable as nucleus pulposus implants due to their adequate swelling ratio, which may restore the annulus fibrosus loading, and their increased mechanical properties, which could possibly restore the height of the intervertebral discs.

Synthesis and Photopolymerization of Tween 20 Methacrylate/N-vinyl-2-Pyrrolidone Blends

“…The water content of the NP ranges from 65 to 90% [22], which is similar to the values of 60 to 85% obtained in the present case and is crucial for the overall mechanical response of disc [23,24]. As described in detail elsewhere [25][26][27], the present T3/NVP hydrogels have been demonstrated to be biocompatible, and compression tests on hydrated specimens indicate viscoelastic behavior comparable with that of human nucleus pulposus, confirming this system to be an excellent candidate for intervertebral disc repair. (Table 1).…”

Stable, self-healing hydrogels from nanofibrillated cellulose, poly(vinyl alcohol) and borax via reversible crosslinking

“…Aside from its abundance and renewability, NFC displays high mechanical strength and stiffness, hydrophilicity, biocompatibility, a low percolation threshold and can readily be modified to introduce functional groups or prepare cellulose derivatives. Recent hydrogels prepared from NFC via photopolymerisation have highlighted its high water retention values and remarkable mechanical reinforcing abilities (14,15). Co-crosslinked NFC-poly(methyl vinyl ether-comaleic acid)−polyethylene glycol hydrogels Goetz et al (16) displayed superior toughness, with optimal values achieved at NFC concentrations of 50 %·wt.…”

The Use of Nanofibrillar Cellulose Hydrogel As a Flexible Three-Dimensional Model to Culture Human Pluripotent Stem Cells

“…They form hydrogels with tuneable physical and chemical properties [24,25] and are shown to be non-cytotoxic [26]. Therefore, they have diverse pharmaceutical and biomedical applications [27][28][29]. When used in cell culture, the NFC hydrogel is mixed with cells without any polymerization process.…”