Bi2O3 nanoparticles exhibit potent broad-spectrum antimicrobial activity and the ability to overcome Ag-, ciprofloxacin- and meropenem-resistance in P. aeruginosa: the next silver bullet of metal antimicrobials?

Device Design and Diagnostic Imaging of Radiopaque 3D Printed Tissue Engineering Scaffolds

3D printed biomaterial implants are revolutionizing personalized medicine for tissue repair, especially in orthopedics. In this study, a radiopaque Bi 2 O 3 doped polycaprolactone ( PCL ) composite is developed and implemented to enable the use of diagnostic X-ray technologies, especially photon counting X-ray computed tomography ( PCCT ), for comprehensive in vivo device monitoring. PCL filament with homogeneous Bi 2 O 3 nanoparticle ( NP ) dispersion (0.8 to 11.7 wt%) are first fabricated. Tissue engineered scaffolds ( TES ) are then 3D printed with the composite filament, optimizing printing parameters for small feature size and severely overhung geometries. These composite TES are characterized via micro-computed tomography ( µ CT ), tensile testing, and a cytocompatibility study, with Bi 2 O 3 mass fractions as low as 2 wt% providing excellent radiographic distinguishability, improved tensile properties, and equivalent cytocompatibility of neat PCL. The excellent radiographic distinguishability is validated in situ by imaging 4 and 7 wt% TES in a mouse model with µCT, showing excellent agreement with in vitro measurements. Subsequently, CT image-derived swine menisci are 3D printed with composite filament and re-implanted in their corresponding swine legs ex vivo . Re-imaging the swine legs via clinical CT allows facile identification of device location and alignment. Finally, the emergent technology of PCCT unambiguously distinguishes implanted menisci in situ.

Strategies for the eradication of intracellular bacterial pathogens

Intracellular pathogens affect a significant portion of world population and cause millions of deaths each year. They can invade host cells and survive inside them and are extremely resistant to immune systems and antibiotics. Current treatments have limitations, and therefore, new effective therapies are needed to combat this ongoing health challenge. Active research efforts have been made to develop many new strategies to eradicate these intracellular pathogens. In this review, we focus on the intracellular bacterial pathogens and first introduce several representative intracellular bacteria and the diseases they cause. We then discuss the challenges in eradicating these bacteria and summarize the current therapeutics for intracellular bacteria. Finally, recent advances in intracellular bacteria eradication are highlighted.

The dual activity of CaONPs as a cancer treatment substance and at the same time resistance to harmful microbes

Nanotechnology holds significant promise for the development of novel and necessary products that enhance human health. Pharmacology and nanotechnology have contributed to developing advanced and highly effective drugs for cancer treatment and combating microbial infections. The microbiological effectiveness against the variety of examined microorganisms was assessed using the time killer curve, scanning electron microscopy (SEM), MIC techniques, and the agar well diffusion method. SEM was utilized to enhance the analysis of the mechanisms underlying the bio-interface interaction and intracellular localization of calcium oxide nanoparticles (CaONPs). The MTT test was used to examine the cytotoxicity of CaONP anticancer activity in various cancer cells, including colon, breast, and hepatic cells. The efficacy of CaONPs as an anticancer medication was elucidated by analyzing the gene expression of both treated and untreated cancer cells. MIC and MBC of CaONPs against Escherichia coli and Staphylococcus epidermidis were 150, 150, 150, and 200 µg/ml, respectively. The MIC and MFC of CaONPs against Candida albicans were 200 µg/ml and 250 µg/ml, respectively. The IC50 values of various CaONPs vary depending on the type of cancer cells. The gene expression analysis of breast cancer cells undergoing treatment revealed the identification of several cancer-controlling genes, namely BAX, BCL2, P53, TERT, KRAS1, KRAS2, and RB1. The study demonstrated the notable antibacterial efficacy of CaONPs, highlighting their potential as cancer therapies.

Harnessing the Dual Antimicrobial Mechanism of Action with Fe(8-Hydroxyquinoline)3 to Develop a Topical Ointment for Mupirocin-Resistant MRSA Infections

8-Hydroxyquinoline (8-hq) exhibits potent antimicrobial activity against Staphylococcus aureus (SA) bacteria with MIC = 16.0-32.0 µM owing to its ability to chelate metal ions such as Mn²⁺, Zn^2+, and Cu²⁺ to disrupt metal homeostasis in bacterial cells. We demonstrate that Fe(8-hq)₃, the 1:3 complex formed between Fe(III) and 8-hq, can readily transport Fe(III) across the bacterial cell membrane and deliver iron into the bacterial cell, thus, harnessing a dual antimicrobial mechanism of action that combines the bactericidal activity of iron with the metal chelating effect of 8-hq to kill bacteria. As a result, the antimicrobial potency of Fe(8-hq)₃ is significantly enhanced in comparison with 8-hq. Resistance development by SA toward Fe(8-hq)₃ is considerably delayed as compared with ciprofloxacin and 8-hq. Fe(8-hq)₃ can also overcome the 8-hq and mupirocin resistance developed in the SA mutant and MRSA mutant bacteria, respectively. Fe(8-hq)₃ can stimulate M1-like macrophage polarization of RAW 264.7 cells to kill the SA internalized in such macrophages. Fe(8-hq)₃ exhibits a synergistic effect with both ciprofloxacin and imipenem, showing potential for combination therapies with topical and systemic antibiotics for more serious MRSA infections. The in vivo antimicrobial efficacy of a 2% Fe(8-hq)₃ topical ointment is confirmed by the use of a murine model with skin wound infection by bioluminescent SA with a reduction of the bacterial burden by 99 ± 0.5%, indicating that this non-antibiotic iron complex has therapeutic potential for skin and soft tissue infections (SSTIs).

Broad-Spectrum Antimicrobial Activity of Ultrafine (BiO)2CO3 NPs Functionalized with PVP That Can Overcome the Resistance to Ciprofloxacin, AgNPs and Meropenem in Pseudomonas aeruginosa

Although it has no known biochemical role in living organisms, bismuth has been used to treat syphilis, diarrhea, gastritis and colitis for almost a century due to its nontoxic nature to mammalian cells. When prepared via a top-down sonication route from a bulk sample, bismuth subcarbonate (BiO)₂CO₃ nanoparticles (NPs) with an average size of 5.35 ± 0.82 nm exhibit broad-spectrum potent antibacterial activity against both the gram-positive and gram-negative bacteria including methicillin-susceptible Staphylococcus aureus (DSSA), methicillin-resistant Staphylococcus aureus (MRSA), drug-susceptible Pseudomonas aeruginosa (DSPA) and multidrug-resistant Pseudomonas aeruginosa (DRPA). Specifically, the minimum inhibitory concentrations (MICs) are 2.0 µg/mL against DSSA and MRSA and 0.75 µg/mL against DSPA and DRPA. In sharp contrast to ciprofloxacin, AgNPs and meropenem, (BiO)₂CO₃ NPs show no sign of developing Bi-resistant phenotypes after 30 consecutive passages. On the other hand, such NPs can readily overcome the resistance to ciprofloxacin, AgNPs and meropenem in DSPA. Finally, the combination of (BiO)₂CO₃ NPs and meropenem shows a synergistic effect with the fractional inhibitory concentration (FIC) index of 0.45.

Fabrication of hierarchical β-Bi2O3/AuAg microspheres for sensitive, selective and rapid detection of environment pollutants by surface-enhanced Raman spectroscopy

In this paper, we report a novel surface-enhanced Raman spectroscopy (SERS) substrate based on hierarchical β-Bi2O3/Au2Ag2 microspheres for rapid, sensitive and selective detection of environment pollutants including o-dianisidine (o-diASD) and Hg2+ in environmental samples. The sheet-like β-Bi2O3 not only provides large specific surface areas for adsorption of molecules and AuAg, but also emerges as semiconductor matrix with chemical enhancement combined with AuAg with electromagnetic enhancement, making promising SERS activity. Particularly, the β-Bi2O3/Au2Ag2 shows high SERS performance for 4-mercaptobenzoic acid and TMB with minimum detectable concentration of 0.1 μg/L with enhancement factor of 3.1 × 107 and 6.3 × 107, respectively. The density functional theory simulations were further adopted to explain the high SERS activity and selectivity for o-diASD and TMB. Finally, the β-Bi2O3/Au2Ag2 was applied to direct detection of o-diASD, and indirect detection of Hg2+ by TMB marking in environmental samples. The linearity range of 0.5-200.0 and 0.2-500.0 μg/L with limit of detection of 0.2 and 0.07 μg/L for o-diASD and Hg2+ ions can be achieved, respectively. This method provides a novel strategy in designing and fabricating SERS substrates with high performance for rapid, sensitive and accurate analysis of environmental pollutants.

SiO2 nanosphere coated tough catheter with superhydrophobic surface for improving the antibacteria and hemocompatibility

Catheter infection is the most common complication after vascular catheter placement, which seriously threatens the survival of critically ill patients. Although catheters with antibacterial drug coatings have been used, catheter infections have not been effectively resolved. In this research, a SiO₂ nanosphere-coated PTFE catheter (PTFE-SiO₂) with enhanced antibacterial and excellent mechanical properties was prepared via dopamine as a graft bridge. The microscopic morphology results show that the nanospheres are uniformly dispersed on the surface of the catheter. The physicochemical characterization confirmed that PTFE-SiO₂ had reliable bending resistance properties, superhydrophobicity, and cytocompatibility and could inhibit thrombosis. Antibacterial results revealed that PTFE-SiO₂ could hinder the reproduction of E. coli and S. aureus. This research demonstrates the hydroxyl-rich materials obtained by hydroboration oxidation have the advantages of better dispersion of functional coatings, indicating their potential for helpful modification of catheters.