Construction of recombinant Omp25 or EipB protein loaded PLGA nanovaccines for Brucellosis protection.

Safe and effective vaccine candidates are needed to address the limitations of existing vaccines against Brucellosis, a disease responsible for substantial economic losses in livestock. The present study aimed to encapsulate Omp25 and EipB proteins, knowledged antigen properties, into PLGA nanoparticles, characterize synthesized nanoparticles with different methods, and assessed their in vitro/in vivo immunostimulatory activities to develop new vaccine candidates. The rOmp25 and EipB proteins produced with recombinant DNA technology were encapsulated into PLGA nanoparticles by double emulsion solvent evaporation technique. The nanoparticles were characterized using SEM, Zeta-sizer, and FTIR instruments to determine size, morphology, zeta potentials, and polydispersity index values, as well as to analyze functional groups chemically. Additionally, the release profiles and encapsulation efficiencies were assessed using UV-Vis spectroscopy. After loading with recombinant proteins, O-NPs reached sizes of 221.2±5.21 nm, while E-NPs reached sizes of 274.4±9.51 nm. The cumulative release rates of the antigens, monitored until the end of day 14, were determined to be 90.39% for O-NPs and 56.1% for E-NPs. Following the assessment of the in vitro cytotoxicity and immunostimulatory effects of both proteins and nanoparticles on the J774 murine macrophage cells, in vivo immunization experiments were conducted using concentrations of 16 µg/ml for each protein. Both free antigens and antigen-containing nanoparticles excessively induced humoral immunity by increasing produced Brucella-specific IgG antibody levels for 3 times in contrast to control. Furthermore, it was also demonstrated that vaccine candidates stimulated Th1-mediated cellular immunity as well since they significantly raised IFN-gamma and IL-12 cytokine levels in murine splenocytes rather than IL-4 following to immunization. Additionally, the vaccine candidates conferred higher than 90% protection from the infection according to challenge results. Our findings reveal that PLGA nanoparticles constructed with the encapsulation of recombinant Omp25 or EipB proteins possess great potential to trigger Brucella-specific humoral and cellular immune response.

Targeted delivery of rifaximin using P6.2-decorated bifunctional PLGA nanoparticles for combating Staphylococcus aureus infections.

The emergence of antibiotic resistance makes the treatment of bacterial infections difficult and necessitates the development of alternative strategies. Targeted drug delivery systems are attracting great interest in overcoming the limitations of traditional antibiotics. Here, we aimed for targeted delivery of rifaximin (RFX) by decorating RFX-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) with synthetic P6.2 peptide, which was used as a targeting agent for the first time. Our results showed that encapsulation of RFX into NPs increased its antibacterial activity by improving its solubility and providing controlled release, while P6.2 modification allowed targeting of NPs to S. aureus bacterial cells. A promising therapeutic approach for bacterial infections, these P6.2-conjugated RFX-loaded PLGA NPs (TR-NP) demonstrated potent antibacterial activity against both strains of S. aureus. The antibacterial activity of RFX-loaded PLGA NPs (R-NP) showed significant results with an increase of 8 and 16-fold compared to free RFX against S. aureus and MRSA, respectively. Moreover, the activity of targeted nanoparticles was found to be increased 32 or 16-fold with an MBC value of 0.0078 µg/mL. All nanoparticles were found to be biocompatible at doses where they showed antimicrobial activity. Finally, it revealed that P6.2-conjugated targeted nanoparticles extremely accumulated in S. aureus rather than E. coli.

Host-Guest Interactions of Caffeic Acid Phenethyl Ester with ß-Cyclodextrins: Preparation, Characterization, and In Vitro Antioxidant and Antibacterial Activity.

The aim of this study is to improve the solubility, chemical stability, and in vitro biological activity of caffeic acid phenethyl ester (CAPE) by forming inclusion complexes with ß-cyclodextrin (ß-CD) and hydroxypropyl-ß-cyclodextrin (Hß-CD) using the solvent evaporation method. The CAPE contents of the produced complexes were determined, and the complexes with the highest CAPE contents were selected for further characterization. Detailed characterization of inclusion complexes was performed by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrospray ionization-mass spectrometry (ESI-MS). pH and thermal stability studies showed that both selected inclusion complexes exhibited better stability compared to free CAPE. Moreover, their antimicrobial activities were evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for the first time. According to the broth dilution assay, complexes with the highest CAPE content (10C/ß-CD and 10C/Hß-CD) exhibited considerable growth inhibition effects against both bacteria, 31.25 µg/mL and 62.5 µg/mL, respectively; contrarily, this value for free CAPE was 500 µg/mL. Furthermore, it was determined that the in vitro antioxidant activity of the complexes increased by about two times compared to free CAPE.

Ketoconazole-loading strategy to improve antifungal activity and overcome cytotoxicity on human renal proximal tubular epithelial cells.

Ketoconazole (KTZ), an antifungal agent used to treat localized or systemic fungal infections by inhibiting ergosterol synthesis, exhibits restricted efficacy within eukaryotic cells owing to its elevated toxicity and limited solubility in water. This study aims to improve the biological activity and overcome cytotoxic effects in the renal system of the hydrophobic KTZ by incorporating it into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) utilizing biomaterial nano-engineering techniques. KTZ-loaded PLGA NPs (KTZ-NPs) were prepared by single emulsion solvent evaporation method and characterized by using dynamic light scattering (DLS), electrophoretic light scattering (ELS), Fourier transform-infrared (FT-IR) spectroscopy and scanning light microscopy (SEM). Particle size and zeta potential of KTZ-NPs were determined as 182.0 ± 3.27 nm and -27.4 ± 0.56 mV, respectively. Antifungal activity was analyzed with the time-kill and top agar dilution methods onCandida albicans(C. albicans) andAspergillus flavus(A. flavus). Both KTZ and KTZ-NPs caused a significant decrease inA. flavuscell growth; however, the same effect was only observed in time-killing analysis onC. albicans, indicating a methodological difference in the antifungal analysis. According to the top agar method, the MIC value of KTZ-NPs againstA. flavuswas 9.1µg ml-1, while the minimum inhibition concentration (MIC) value of KTZ was 18.2µg ml-1. The twofold increased antifungal activity indicates that nanoparticular drug delivery systems enhance the water solubility of hydrophobic drugs. In addition, KTZ-NPs were not cytotoxic on human renal proximal tubular epithelial cells (HRPTEpCs) at fungistatic concentration, thus reducing fungal colonization without cytotoxic on renal excretion system cells.

A new strategy to achieve high antimicrobial activity: green synthesised silver nanoparticle formulations with Galium aparine and Helichrysum arenarium.

Silver nanoparticles (AgNPs), which have recently gained attention due to their antimicrobial activity, can also be produced by green synthesis. The aims of this study were to (i) characterise green synthesized AgNPs using microwave-assisted aqueous extracts of Galium aparine (G-AgNPs) and Helichrysum arenarium (H-AgNPs) and (ii) investigate the combined antimicrobial effects of the G- and H-AgNPs in different ratios. Nanoparticle formation and reactions were determined with UV-Vis spectroscopy. The G-AgNPs were 52.0±10.9 nm in size, with a 0.285±0.034 polydispersity index (PDI), and a -17.9±0.9 mV zeta potential. For H-AgNPs these characteristics were 23.9±1.0 nm, 0.280±0.032, and -21.3±2.7 mV, respectively. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) confirmed that the particles were monodisperse and spherical. The Fourier transform-infrared spectroscopy (FT-IR) results showed the presence of reducing agents that stabilised the AgNPs. Three different nanoformulations (NF-1, NF-2, and NF-3) were prepared by combining these two synthesised nanoparticles in different ratios and their antimicrobial activity was tested against E. coli, S. aureus, C. albicans, and A. flavus. Our study is the first to show that combining AgNPs from two different biological sources can produce effective nanoformulations with improved antibacterial activity against E. coli and S. aureus. These nanoformulations showed lower minimum inhibitory concentrations (31.25 µg/mL against E. coli with all NFs; 62.5 µg/mL for NF-1 and 125 µg/mL for NF-2/3 against S. aureus) than G-AgNPs (62.5 µg/mL for E. coli) or H-AgNPs (125 µg/mL for S. aureus) alone. Their high combined inhibitory effect against E. coli (NF-1-3) was synergistic and against S. aureus (NF-2 and NF-3) potentially additive. Considering such promising results, we believe our study provides some direction for new research and strategies in antimicrobial therapeutics.