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Antimicrobial potential of bioactive glass (BAG) makes it promising for implant applications, specifically overcoming the toxicity concerns associated with traditional antibacterial nanoparticles. The 58S composition of BAG (with high Ca and absence of Na) has been known to exhibit excellent bioactivity and antibacterial behaviour, but the mechanisms behind have not been investigated in detail. In this pioneering study, we are using Atomic Force Microscopy (AFM) to gain insights into 58S BAG's adhesive interactions with planktonic cells of both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria; along with the impact of crystallinity on antibacterial properties. We have recorded greater bacterial inhibition by amorphous BAG compared to semi-crystalline glass–ceramics and stronger effect against gram-negative bacteria via conventional long-term antibacterial tests. AFM force distance curves has illustrated substantial bonding between bacteria and BAG within the initial one second (observed at a gap of 250 ms) of contact, with multiple binding events. Further, stronger adhesion of BAG with E.coli (~ 6 nN) compared to S. aureus (~ 3 nN) has been found which can be attributed to more adhesive nano-domains (size effect) distributed uniformly on E.coli surface. This study has revealed direct evidence of impact of contact time and 58S BAG's crystalline phase on bacterial adhesion and antimicrobial behaviour. Current study has successfully demonstrated the mode and mechanisms of initial bacterial adhesion with 58S BAG. The outcome can pave the way towards improving the designing of implant surfaces for a range of biomedical applications. [ABSTRACT FROM AUTHOR]

Conservation of embankment soil along the rivers is a global challenge. The existing solutions including rigid structures and cement-based techniques pose risks to the sensitive river ecology. The trending biopolymer (Bp) based soil stabilisation technique has shown enormous potential to stabilise loose and soft soils. The rheology of such biopolymer solutions is expected to play a critical role in soil stabilisation, especially in a wet environment such as riverbanks. In this study, four different levels of xanthan gum treatment (0.5 to 1.25% by soil weight) are investigated for stabilising the soil collected from an erosion-prone bank of the Brahmaputra River basin. The rheological properties of the intended biopolymer solutions are investigated extensively prior to their application. Later, the degree of stabilisation of the biopolymer-treated soil is determined by evaluating their unconfined compressive strength (UCS) and secant modulus. The erosion characteristics of the treated samples were evaluated using an in-house built apparatus. The shear-thinning and viscoelastic parameters of the biopolymer solutions have been quantified with the rheological analysis. The UCS strength test revealed a consistent increase up to 1.6 MPa with an increase in the biopolymer treatment of 1.25%. The erosion test revealed that the biopolymer treatment delayed the erosion process. However, it did not completely cease the erosion. The microstructure analysis revealed that the strong biopolymer bridging acts as a dampener in the soil pores to delay erosion. This study unravels the critical role of rheological factors, which are essential in reproducing the desired results from the geotechnical laboratories to field-scale applications. [ABSTRACT FROM AUTHOR]