The development of materials that can more efficiently
administer
antimicrobial agents in a controlled manner is urgently needed due
to the rise in microbial resistance to traditional antibiotics. While
new classes of antibiotics are developed and put into widespread usage,
existing, inexpensive compounds can be repurposed to fight bacterial
infections. Here, we present the synthesis of amine-functionalized
SBA-15 mesoporous silica nanomaterials with physisorbed rafoxanide
(RFX), a commonly used salicylanilide anthelmintic, and anchored Cu(II)
ions that exhibit enhanced antimicrobial efficacy against the pathogenic
bacterium Staphylococcus aureus. The
synthesized nanomaterials are structurally characterized by a combination
of physicochemical, thermal, and optical methods. Additionally, release
studies are carried out in vitro to determine the effects of pH and
the synthetic sequence used to produce the materials on Cu(II) ion
release. Our results indicate that SBA-15 mesoporous silica nanocarriers
loaded with Cu(II) and RFX exhibit 10 times as much bactericidal action
against wild-type S. aureus as the
nanocarrier loaded with only RFX. Furthermore, the synthetic sequence
used to produce the nanomaterials could significantly affect (enhance)
their bactericidal efficacy.