Inclusion of sulfamethoxazole in a novel CuFe 2 O 4 nanoparticles/mesoporous silica‐based nanocomposite: Release kinetics and antibacterial activity

Gold-Based Nanostructures for Antibacterial Application

Bacterial infections have become a fatal threat because of the abuse of antibiotics in the world. Various gold (Au)-based nanostructures have been extensively explored as antibacterial agents to combat bacterial infections based on their remarkable chemical and physical characteristics. Many Au-based nanostructures have been designed and their antibacterial activities and mechanisms have been further examined and demonstrated. In this review, we collected and summarized current developments of antibacterial agents of Au-based nanostructures, including Au nanoparticles (AuNPs), Au nanoclusters (AuNCs), Au nanorods (AuNRs), Au nanobipyramids (AuNBPs), and Au nanostars (AuNSs) according to their shapes, sizes, and surface modifications. The rational designs and antibacterial mechanisms of these Au-based nanostructures are further discussed. With the developments of Au-based nanostructures as novel antibacterial agents, we also provide perspectives, challenges, and opportunities for future practical clinical applications.

Enhancing efficacy of existing antibacterials against selected multiple drug resistant bacteria using cinnamic acid-coated magnetic iron oxide and mesoporous silica nanoparticles

Developing new antibacterial drugs by using traditional ways is insufficient to meet existing challenges; hence, new strategies in the field of antibacterial discovery are necessary. An alternative strategy is to improve the efficacy of currently available antibiotics. Herein, the antibacterial efficacy of drugs (Cefixime, Sulfamethoxazole, and Moxifloxacin) and drug-loaded cinnamic acid-coated magnetic iron oxide and mesoporous silica nanoparticles (NPs) was elucidated versus Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae, neuropathogenic Escherichia coli K1 and Serratia marcescens) and Gram-positive bacteria (Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Streptococcus pneumoniae, and Bacillus cereus). NPs were synthesized by co-precipitation and the Stöber method, and characterized by Fourier transform-infrared spectroscopy, Zetasizer, and Atomic force microscopy. Lactate dehydrogenase (LDH) assays were accomplished to determine drug cytotoxicity against human cells. Spherical NPs in the range of 118-362 nm were successfully synthesized. Antibacterial assays revealed that drugs conjugated with NPs portray enhanced bactericidal efficacies against multiple drug resistant bacteria compared to the drugs alone. Of note, Cefixime-conjugated NPs against Escherichia coli K1 and Methicillin- resistant Staphylococcus aureus, resulted in the complete eradication of all bacterial isolates tested at significantly lower concentrations compared to the antibiotics alone. Likewise, conjugation of Moxifloxacin resulted in the complete elimination of E. coli K1 and MRSA. Of note, nano-formulated drugs presented negligible cytotoxicity against human cells. These results depict potent, and enhanced efficacy of nano-formulated drugs against medically important bacteria and can be used as alternatives to current antibiotics. Future in vivo studies and clinical studies are warranted in prospective years to realize these expectations.

Survey of antibacterial activity and release kinetics of gold-decorated magnetic nanoparticles of Fe0 conjugated with sulfamethoxazole against Escherichia coli and Staphylococcus aureus

Drug delivery of antibiotics with magnetic nanoparticles improved by coating metals such as gold and silver has recently been studied. This work describe a simple method to synthesize modified magnetic nanoparticles which have high ability to modify the customary formulation of antibiotics such as sulfamethoxazole (SMX) and pursuant study of adsorption-desorption (release) of this drug. These synthesized nanoparticles were characterized by different methods, including field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and mapping, Fourier-transform infrared spectroscopy, X-ray diffraction, vibrating-sample magnetometry, thermogravimetric analysis and zeta potential test. Present assay showed a well correlation with the introduced carrier for the drug. Also the hypothesis were proved by some adsorption isotherm models and drug kinetics studies of carriers with different drug release kinetics models. This study confirmed the adsorption isotherm models and kinetics of drug sorbate are Temkin and Pseudo-First-Order Lagergren models, respectively; the kinetics of drug release from this carrier is based on Zero-Order model. The values of MIC in antibacterial test for pure SMX and SMX conjugated nanoparticles against Escherichia coli were calculated to be 14 and 2.5 μg/mL, respectively, and these values against Staphylococcus aureus were 24 and 1.25 μg/mL, respectively.

PEG-mesoporous material modified by superparamagnetic nanoparticles as a delivery system of cefotaxime

The fight against infectious bacterial diseases has been taking major steps forward by designing new nanodrugs and nanoscale biological carriers with unique physicochemical properties. Here, polyethylene glycol (PEG)-silica mesoporous material/superparamagnetic CuFe₂O₄ nanoparticle nanocomposite was synthesized using a facile chemical approach, and proposed as a carrier for the delivery of cefotaxime (CTX) drug. The resulting nanocomposite material and nanocomposite CTX drug carrier were characterized by different techniques. Antibacterial activity of the nanocomposite drug carrier was investigated against E.coli and S. aureus bacteria, and compared with that of commercial CTX drug. It was found that the minimum inhibitory concentrations of the nanocomposite drug carrier (1.25 and 5 μg/mL) were significantly less than those of the commercial drug (10 and 80 μg/mL) against the bacteria. Furthermore, enhanced performance of the nanocomposite CTX carrier for both the Gram-negative and Gram-positive bacteria was evidenced.

Moxifloxacin and Sulfamethoxazole-Based Nanocarriers Exhibit Potent Antibacterial Activities

Antibiotic resistance is a major concern given the rapid emergence of multiple-drug-resistant bacteria compared to the discovery of novel antibacterials. An alternative strategy is enhancing the existing available drugs. Nanomedicine has emerged as an exciting area of research, showing promise in the enhanced development of existing antimicrobials. Herein, we synthesized nanocarriers and loaded these with available clinically approved drugs, namely Moxifloxacin and Sulfamethoxazole. Bactericidal activity against Gram-negative (Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella enterica) and Gram-positive (methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, and Bacillus cereus) bacteria was investigated. To characterize the nanocarriers and their drug-loaded forms, Fourier-transform infrared spectroscopy, dynamic light scattering, and atomic force microscopy were utilized. Antibacterial assays and hemolysis assays were carried out. Moreover, lactate dehydrogenase assays were performed to determine cytotoxicity against human cells. The results depicted the successful formation of drug-nanocarrier complexes. The potent antibacterial activities of the drug-loaded nanocarriers were observed and were significantly enhanced in comparison to the drugs alone. Hemolysis and cytotoxicity assays revealed minimal or negligible cytotoxic effects against human red blood cells and human cells. Overall, metronidazole-based nanocarriers loaded with Moxifloxacin and Sulfamethoxazole showed enhanced bactericidal effects against multiple-drug-resistant bacteria compared with drugs alone, without affecting human cells. Our findings show that drug-loaded nanocarriers hold promise as potent chemotherapeutic drugs against multiple-drug-resistant bacteria.