Abstract:
Magnesium-based hydrotalcite (MAL), aspartic acid (ASP)-loaded hydrotalcite (MALA), ASP and Ag
+ co-loaded hydrotalcite (MALAA) were prepared by nucleation crystallisation, their hydrotalcite structure and morphology were characterised by X-ray diffraction and transmission electron microscopy. Both ASP and Ag
+ were found successfully loaded onto MAL with morphological changes. Their antibacterial effect on
Staphylococcus aureus (
S. aureus) was examined by colony counting method. MAL inhibition of
S. aureus growth was found to be 5.8% at 4 mg·mL
−1, but MALAA inhibition was 99.7%. The anti-bacterial mechanism of these modified magnesium-based hydrotalcites was examined by inductively coupled plasma and UV-visible spectrophotometer techniques. MALA was found adsorbed electrostatically on the negatively charged
S. aureus, with changed MALA morphology, to increase the overall contact area with bacteria. Introduction of Ag
+, by increasing the potential difference between MALAA and the bacterial cell surface, promoted the rupture of
S. aureus cell membrane, leading to significantly-increased extracellular cations (K
+, Ca
2+, and Mg
2+) and proteins. MALA but especially MALAA due to their antibacterial activities will be very useful packing materials in the food, cosmetics industries.