S. aureus ATCC25923, respectively. Meanwhile, a slightly lower activity against
P. aeruginosa ATCC27853 (11.1 and 13.2 mm) was demonstrated by CF3 and CF4, respectively. MRSA (
S. aureus ATCC43300), showed moderate resistance where CF3 and CF4 exhibited 11.7 mm and 13.5 mm inhibition zones, respectively.
Such findings indicate that the hybrid NPs are responsible for the antibacterial activity of the composite fibers. The NPs are released steadily over 48-h incubation period, and exhibit zones of inhibition against the three selected bacterial strains. It can be noted that the Gram-negative
P. aeruginosa showed higher resistance than
S. aureus and MRSA. This might be attributed to the intrinsic difference in their cell wall structure. The Gram-negative bacterial cell wall is thick, hence acting as a strong biological barrier against biocides. It consists of lipids, proteins and lipopolysaccharides (LPS). However, the thinner and loose Gram-positive bacterial cell wall, due to missing of LPS, can be easily destroyed and penetrated by the NPs. Thus, the penetrated NPs might bind with DNA and cause denaturation.