Nanocomposites from functionalized bacterial cellulose and PHBV

What is it about?

Bacterial cellulose (BC) sponges are valuable materials for tissue engineering and regenerative medicine due to their biocompatibility and nano-sized fibrous network with interconnected open porosity. However, their instability in physiological environment and poor mechanical properties are the main issues that need to be solved in order to obtain appropriate three-dimensional scaffolds for tissue formation. In this work, a bacterial polyester, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and a simple impregnation method were used to improve the properties of BC sponges for biomedical application. Highly hydrophilic BC was surface functionalized by amination (BCA) to improve its affinity to PHBV. PHBV uptake in BC and BCA sponges depended on the PHBV concentration and was confirmed by Fourier transform infrared spectroscopy and by the increase in density after impregnation. SEM investigation showed that PHBV was deposited on the BC nanofibrous network, in some conditions forming a tridimensional honeycomb ordered structure with uniform micrometer pores. Thermogravimetric and kinetic analyses showed a delay in the thermal degradation for the BCA nanocomposites sponges compared to the BC ones and an increase in the activation energy of degradation compared to neat PHBV. Better compression strength was obtained for BCA/PHBV nanocomposite sponges due to the increased interactions between the polymer and the aminated cellulose substrate. Swelling tests showed that BC and BCA sponges did not resist and completely disintegrated in 90 min of incubation in phosphate-buffered saline, but a good stability in this simulated physiological environment was obtained after impregnation with PHBV. The swelling degree varied between 1200% and 2400% for BC/PHBV and between 700% and 1200% for BCA/PHBV sponges, which are high enough to allow the diffusion of water and the transport of nutrients. Therefore, these easily obtained BC/PHBV and BCA/PHBV nanocomposite sponges, with improved properties, could be a promising option for tissue engineering scaffolds.

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Why is it important?

Bacterial cellulose (BC) sponges with improved stability in physiological environment and good mechanical properties were obtained by a simple method and designed for tissue engineering and regenerative medicine. Highly hydrophilic BC was surface functionalized by amination (BCA) to improve its affinity to PHBV. BC/PHBV and BCA/PHBV nanocomposite sponges, showing improved properties, are a promising option for soft tissue engineering scaffolds.