Isolation And Characterization Of Cassava Fibre For Tissue Engineering Scaffold Application

ABSTRACT

Cassava bagasse and its extracted cellulose fibres have seen frequent application mostly

in the packaging industry as reinforcement material in plastic composites development.

However, the material properties such as the mechanical properties of the single

elementary cassava cellulose fibres have not been examined and reviewed literature

does not show its potential use in the development of tissue engineering scaffolds for

cell culture. The study, therefore, characterized the mechanical properties,

physicochemical, morphological and microstructural characteristics and thermal

degradation profiles of single elementary cellulose fibre as well as the central vascular

fibre (“thick-core fibre) isolated from three genotypes of cassava (tagged in this study

as ID4, ID6 and AF). Additionally, the study examined the effect of incorporating

cassava cellulose microfibres as reinforcement on the mechanical properties and

microstructure characteristics of three-dimensional gelatin scaffolds. Non-treated

isolated cassava fibres were tested according to ASTM C1557. Three-dimensional

cassava microfibre/gelatin scaffolds with different fibre weight fractions were

fabricated using phase separation and freeze-drying methods. Tensile test results

showed that there was no significant difference (p > 0.05) in mechanical properties

recorded between the single elementary fibre and vascular fibre (thick-core) for the

three cassava genotypes. Different genotypes of cassava fibre showed significant

differences (p < 0.05) in tensile strength and Young’s modulus, with ID4 fibre

recording the highest average tensile strength of 7.567 ± 3.844 MPa and highest elastic

modulus of 336.485 ±130.803 MPa. XRD analysis showed similar diffraction pattern

with minimal variation in signal intensities for both single and thick-core fibres for all

cassava genotypes suggesting nonsignificant differences in crystalline structure

between them. TGA analysis showed that cassava fibre is thermally stable between the

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temperatures of 100 °C – 200 °C. The cassava cellulose microfibre/gelatin scaffolds

fabricated showed rough surfaces compared to pure gelatin scaffolds and were highly

porous with surface porosity ranging between 84 and 90%, and had interconnected

pores of average size 36 ±12 μm. Gelatin scaffolds containing up to 7% cassava

cellulose microfibre load recorded a maximum compressive strength of 0.29±0.02

MPa, about eight (8) times higher than that for the pure gelatin scaffolds and average

Young’s modulus of 1.31 ±0.03 MPa, about four times higher than pure gelatin

scaffolds. Preliminary theoretical modelling using Halpin-Tsai model could accurately

explain the variabilities in the compression modulus of the gelatin composite scaffolds.

In all, the results showed that cassava fibre has considerable mechanical strength and

stiffness and can be used as reinforcement filler to improve the mechanical integrity of

tissue engineering polymer scaffolds. The cassava fibre/gelatin scaffolds showed

surface architecture that could improve cell–matrix adhesion and efficient cell seeding

and diffusion of nutrients during cell culture.