Silicon-infused bacterial cellulose: in situ bioprocessing for tailored strength and surface characteristics

In this study we investigate the use of in situ bioprocessing for the production and surface modification of bacterial cellulose (BC) with silicon additives. The surface properties and tensile strength of the BC were studied and compared with plain BC. The effect the modification exhibited on the survivability of the bacteria was assessed by optical density measurements and found that the addition of the modification marginally slowed growth in the case of Tetramethyl orthosilicate (TMOS) and did not affect the growth in the case of Tetraethyl orthosilicate (TEOS). Characterisation of the modified BC was carried out using FTIR, EDX and confirmed the presence of silicon in the material. The width of fibres in the microstructure of BC was measured using SEM. Two different silicon modifications were used to modify the BC, it was shown that the TMOS modification decreased the tensile strength but that the TEOS increased the tensile strength of the BC fibres compared to plain BC. In addition, we found that the washing conditions of 1% NaOH (w/v), industrial methylated spirit (IMS), and deionised water (DI) showed some impact on the properties of the samples, particularly the IMS produced a reduced contact angle in the modified samples. However, the contact angle increased in the case of TEOS modification with the NaOH wash. In conclusion this study shows a novel method of modifying BC materials in-situ using silicon additives for increased tensile strength and the potential for tuneable hydro interactions.