Copper-modified mesoporous silica nanomaterials and their potential for antimicrobial applications
Creators: name: Ramírez-Hernández, Maricely
Publisher: name: No Publisher Supplied
Year: 2023

description: Mesoporous silica nanoparticles (MSNs) have been a topic of great interest in various fields, including biomedical applications, due to their distinct properties and structures. MSNs are particularly noteworthy for their potential applications in catalysis, drug delivery systems, sensing, and environmental remediation.The work presented here demonstrates how MSNs can be surface engineered with different functional groups and loaded with copper ions to enhance their bactericidal and electrocatalytic properties. This can be built upon to design novel materials for biomedical applications like antimicrobial formulations and water remediation to remove emerging antibiotic pollutants from there.Chapter 2 examines the antimicrobial effects of Cu(II) counterions on the performance of diamino-modified SBA-15 materials through biological assays and structural characterization. Cu(II) gluconate hosted in mesoporous silica showed a tenfold improvement over free-floating salt. At the same time, S. aureus mutants were more susceptible to Cu(II) acetate hosted in silica nanomaterial without a primary carbon source. These findings offer valuable insights into the design of nanocomposite materials for antimicrobial applications.In Chapter 3, MSNs with three different organofunctional groups, namely, diamino, phosphonate, and thiol, were prepared to investigate their effect on Cu(II) ion loading and bactericidal properties against gram-positive S. aureus and gram-negative E. coli. The thiol-functionalized nanomaterials showed more significant antimicrobial activity against both bacteria than their diamino and phosphonate-modified counterparts, suggesting their potential use in broad-spectrum bacterial control.In Chapter 4, rafoxanide and Cu(II) ions were loaded into diamino-functionalized SBA-15 materials to explore their bactericidal activity against gram-positive and gram-negative bacteria.1 The effects of pH and the synthetic sequence utilized to create the materials were also investigated using in vitro release investigations for Cu(II) ion release. Our findings suggested that bactericidal activity against wild-type S. aureus is ten times greater in SBA-15 mesoporous silica nanocarriers loaded with Cu(II) and rafoxanide than in the nanocarrier loaded with only rafoxanide. The method of synthesis utilized to create the nanomaterials may also have a significant impact on enhancing the material's ability to their ability to kill bacteria.In Chapter 5, peroxymonosulfate (PMS)-activation was used to activate SBA-15 supported on nickel foam (NF) and polyaniline with copper systems (CPS) to electrocatalytically break down the antibiotic tetracycline.2 Within 5 minutes, almost 90% of the tetracycline in solution was broken down using PMS by the synthesized material that was supported on NF cathode. The findings showed that PMS accelerates tetracycline degradation and that PMS activation is crucially dependent on the CPS-NF cathode. The generation of reactive oxygen species at the surface of the CPS-NF cathode to break down tetracycline is favored by the Cu+ and Cu2+ species created from CPS-NF.Chapter 6 highlights additional experiments, such as the grafting of enzymes and other copper salts into MSNs to tackle biofilm. Additionally, this chapter outlines challenges to overcome in quantifying biofilm inhibition with solid substrates and future directions to consider bringing the materials closer to end use in society. To summarize, this work aims to contribute to the field by addressing the following: •The bactericidal effect of different copper counterions loaded onto diamino-functionalized SBA-15 delivery platforms.•The bactericidal effect of Cu(II) acetate loaded on SBA-15 with ligands of different functional groups.•The effect of combining Cu(II) and anthelmintics on the bactericidal effect against S. aureus and E. coli.•The combination of polyaniline and Cu(II) ions on SBA-15 for the electrochemical degradation of antibiotics.