Overcoming Antibiotic Resistance: Playing the ‘Silver Nanobullet’ Card

Abstract

Enhancing the antibacterial activity of old antibiotics by a multitarget approach, such as combining antibiotics with metal nanoparticles, is a valuable strategy to overcome antibacterial resistance. In this work, the synergistic antimicrobial effect of silver nanoparticles and antibiotics, immobilized on a solid support, was investigated. Nanometric layered double hydroxides (LDH) based on Zn(II) and Al(III) were prepared by the double microemulsion technique. The dual function of LDH as an anionic exchanger and support for metal nanoparticles was exploited to immobilize both silver and antibiotics. Cefazolin (CFZ), a β-lactam, and nalidixic acid (NAL), a quinolone, were selected and intercalated into LDH obtaining ZnAl-CFZ and ZnAl-NAL samples. These samples were used for the growth of silver nanoparticles with dimension ranging from 2.5 to 8 nm. Silver and antibiotics release profiles, from LDH loaded with antibiotics and Ag/antibiotics, were evaluated in two different media: water and phosphate buffer. Interestingly, the release profiles are affected by both the acceptor media and the presence of silver. The synergistic antibacterial activity of LDH containing both silver and antibiotics were investigated on gram-positives (Staphylococcus aureus and Streptococcus pneumoniae) and gram-negatives (Pseudomonas aeruginosa) and compared with the plain antimicrobials and LDH containing only antibiotics or silver.

Mechanical and Biological Properties of Titanium and Its Alloys for Oral Implant with Preparation Techniques: A Review

“…Other bacteria-inhibiting methods are sterilization where bactericidal materials are coated on the titanium alloy surface or compounded into the titanium alloy for a long-term release of bactericidal effects. Silver [110], copper [111], zinc [112], chlorhexidine [113], and some antibiotics [114,115] are promising antimicrobial materials. Zhou, et al [116] prepared an F-doped TiO 2 microporous coating on titanium to enhance bacterial resistance.…”