Extraction of cellulose nano-crystals from Polyalthia longifolia and Terminalia catappa leaf litter and the synthesis of low-cost CNC-based hydrogel for articular cartilage
Department of Biotechnology, R.V College of Engineering, Bengaluru, India.
Research Article
GSC Biological and Pharmaceutical Sciences, 2021, 16(01), 019-026.
Article DOI: 10.30574/gscbps.2021.16.1.0197
Publication history:
Received on 06 June 2021; revised on 10 July 2021; accepted on 13 July 2021
Abstract:
Due to the rise in demand for biodegradable and renewable materials, the synthesis of CNCs from lignocellulosic biomass opens up a new avenue for the creation and application of novel materials in nanotechnology. The CNC-based hydrogels appear to be a favorable material in various applications due to their excellent mechanical strength, biodegradability, biocompatibility, and low toxicity.
This work aimed to utilize the fallen leaves for the extraction of Cellulose Nano-crystals (CNC) from Polyalthia longifolia and Terminalia catappa leaf litter. Leaves mainly consist of cellulose hence used for the extraction of nanocellulose. Alkali treatment was performed with aqueous sodium hydroxide, followed by bleaching with aqueous sodium chlorite. Sulphuric acid hydrolysis was used for the extraction of CNC. The morphology, structure, functional groups, and crystallinity of the retrieved CNC were studied using a Transmission Electron Microscope (TEM), Fourier Transformed Infrared spectroscopy (FTIR), and X-Ray Diffraction (XRD).
The shape was rod-like for both P. longifolia and T. catappa and the CNC’s crystallinity index was enhanced to 72.40% and 73.95%, respectively. The TEM micrographs revealed that the impurities present on the leaf fibres were successfully removed by alkali treatment and subsequent bleaching further purified the fibres, leaving behind mostly cellulose while the hemicellulose and lignin were removed, which was revealed in FTIR spectra.
The obtained CNC was used in the preparation of hydrogel by cross-linking with natural polymers like sodium alginate and gelatin. A Freeze-thawing process was carried out for the fabrication of hydrogel. The resulting hydrogel can be used as a substitute for cartilage applications.
Keywords:
Cellulose Nano-crystal (CNC); Sulphuric Acid Hydrolysis; Transmission Electron Microscope (TEM); Fourier Transformed Infrared spectroscopy (FTIR); X-Ray Diffraction (XRD); Articular cartilage
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