Comparative assessment of green and chemically synthesized glutathione capped silver nanoparticles for antioxidant, mosquito larvicidal and eco-toxicological activities.

A comparative assessment of AgNPs synthesized through three different routes viz. clove bud extract mediated AgNPs, sodium borohydride AgNPs and Glutathione (GSH) capped AgNPs for antioxidant and mosquito larvicidal activities was the major focus of the present study. The nanoparticles were characterized using UV-VIS spectrophotometry, dynamic light scattering (DLS), X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Characterization studies revealed the synthesis of stable, crystalline AgNPs measuring 28 nm, 7 nm and 36 nm for green, chemical and GSH-capped AgNPs respectively. FTIR analysis exhibited the surface functional moieties that were responsible for reduction, capping and stabilizing AgNPs. Antioxidant activity was found to be 74.11%, 46.62% and 58.78% for clove, borohydride and GSH-capped AgNPs respectively. Mosquito larvicidal bioactivity of AgNPs against Aedes aegypti IIIrd instar larvae depicted clove AgNPs being most effective (LC50-4.9 ppm, LC90-30.2 ppm) followed by GSH-capped (LC50-20.13 ppm, LC90-46.63 ppm) and borohydride AgNPs (LC50-13.43 ppm, LC90-160.19 ppm) after 24 h. Toxicity screening against aquatic model Daphnia magna revealed Clove mediated and GSH-capped AgNPs to be safer as compared to the borohydride AgNPs. It may be envisaged that green and capped AgNPs may be further explored for diverse biomedical and therapeutic applications.

Recent progress in dichalcophosphate coinage metal clusters and superatoms.

Atomically precise clusters of group 11 metals (Cu, Ag, and Au) attract considerable attention owing to their remarkable structure and fascinating properties. One of the unique subclasses of these clusters is based on dichalcophosphate ligands of [(RO)2PE2]- type (E = S or Se, and R = alkyl). These ligands successfully stabilise the most diverse Cu, Ag, and Au clusters and superatoms, spanning from simple ones to amazing assemblies featuring unusual structural and bonding patterns. It is noteworthy that such complicated clusters are assembled directly from cheap and simple reagents, metal(I) salts and dichalcophosphate anions. This reaction, when performed in the presence of a hydride or other anion sources, or foreign metal ions, results in hydrido- or anion-templated homo- or heteronuclear structures. In this feature article, we survey the recent advances in this exciting field, highlighting the powerful synthetic capabilities of the system "a metal(I) salt - [(RO)2PX2]- ligands - a templating anion or borohydride" as an inexhaustible platform for the creation of new atomically precise clusters, superatoms, and nanoalloys.

A single coned Poly-Biz moderator designed for animal irradiation in boron neutron capture therapy.

BNCT is considered to be a promising method for the treatment of malignant tumors, which ensures the selective destruction of malignant tumor cells by accumulating non-radioactive atomic boron-10 nuclei in them and subsequent irradiation with neutrons. As a result of the absorption of a neutron by boron, a nuclear reaction occurs with the release of energy in a cell containing boron, which leads to its death. To date, two drugs for targeted delivery of boron, boronophenylalanine and sodium borocaptate, have been developed, which ensures selective accumulation of boron in a number of tumors, and a number of charged particle accelerators with neutron-generating targets and with neutron beam shaping assemblies have been developed providing the quality of the neutron beam required for therapy. The paper presents a critical analysis of the methods used to form a therapeutic neutron beam and proposes a new concept of a neutron beam shaping assembly, supported by the results of numerical simulation validated by in-phantom measurements.

Sodium-borohydride exfoliated bismuthene loaded with Mitomycin C for chemo-photo-radiotherapy of triple negative breast cancer.

In current study, a new remotely controlled drug delivery, radio-sensitizing, and photothermal therapy agent based on thioglycolic acid modified bismuth nanosheets is thoroughly evaluated. Bismuth nanosheets were synthesized using sodium borohydride (NaBH4) and Tween 20 through low energy (400 W) sonication within 2 h. The resultant nanosheets were 40-60 nm in size and 1-3 atomic layers in thickness. The morphological and structural characteristics of the nanosheets were studied using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy and ultraviolet spectroscopy. The surface of the nanosheets was modified using thioglycolic acid, which resulted in enhanced Mitomycin C loading capacity to 274.35% and circumvented the burst drug release due to the improved electrostatic interactions. At pH 7.4 and 5.0, the drug release was significantly boosted from 45.1 to 69.8%, respectively. Thioglycolic acid modified bismuth nanosheets under 1064 nm laser irradiation possessed photothermal conversion efficiency of η=51.4% enabling a temperature rise of 24.9 °C at 100 µg/ml in 5 min. The combination of drug delivery, photothermal therapy, and radio-sensitization greatly damaged the MDA-MB-231 cells through apoptosis and diminished their colony forming.

The impact of TP53 status of tumor cells including the type and the concentration of administered 10B delivery agents on compound biological effectiveness in boron neutron capture therapy.

Human head and neck squamous cell carcinoma cells transfected with mutant TP53 (SAS/mp53) or neo vector (SAS/neo) were inoculated subcutaneously into left hind legs of nude mice. After the subcutaneous administration of a 10B-carrier, boronophenylalanine-10B (BPA) or sodium mercaptododecaborate-10B (BSH), at two separate concentrations, the 10B concentrations in tumors were measured using γ-ray spectrometry. The tumor-bearing mice received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all intratumor proliferating (P) tumor cells, then were administered with BPA or BSH. Subsequently, the tumors were irradiated with reactor neutron beams during the time of which 10B concentrations were kept at levels similar to each other. Following irradiation, cells from some tumors were isolated and incubated with a cytokinesis blocker. The responses of BrdU-unlabeled quiescent (Q) and total (= P + Q) tumor cells were assessed based on the frequencies of micronucleation using immunofluorescence staining for BrdU. In both SAS/neo and SAS/mp53 tumors, the compound biological effectiveness (CBE) values were higher in Q cells and in the use of BPA than total cells and BSH, respectively. The higher the administered concentrations were, the smaller the CBE values became, with a clearer tendency in SAS/neo tumors and the use of BPA than in SAS/mp53 tumors and BSH, respectively. The values for BPA that delivers into solid tumors more dependently on uptake capacity of tumor cells than BSH became more alterable. Tumor micro-environmental heterogeneity might partially influence on the CBE value. The CBE value can be regarded as one of the indices showing the level of intratumor heterogeneity.

Fluorescent property of carbon dots extracted from cigarette smoke and the application in bio-imaging.

Cigarette smoke is one of the six major pollution sources in the room air. It contains large number of particles with size less than 10 nm. There exist carbon dots (CDs) in cigarette smoke which have strong fluorescence and with good bio-compatibility and low toxicity. CDs in cigarette smoke can be applied in bio-imaging which has great potential applications in the integration of cancer diagnosis and treatment. In this paper, CDs were extracted from cigarette smoke. Then, sodium borohydride was added to CDs aqueous solution for reduction and the reduced CDs (R-CDs) were used for biological cell imaging. The results indicate that the CDs with the particle size <10 nm in cigarette smoke are self-assembled by the polymerizated polycyclic aromatic hydrocarbons (PAHs) and ammonium nitrite which are disk nano-structure composed of sp2/sp3 carbon and oxygen/nitrogen groups or polymers. Sodium borohydride can reduce the carbonyl group on the surface of CDs to hydroxyl group and increase the ratio of the Na 1s ratio of the CDs from 1.86 to 7.42. The CDs can emit blue fluorescence under ultraviolet irradiation. After reduction, the R-CDS have the intensity of fluorescence 7.2 times than before and the fluorescence quantum yield increase from 6.13% to 8.86%. The photoluminescence (PL) wavelength of R-CDS have red-shift of 7 nm which was due to the increasing of Na element ratio. The onion epidermal cells labeled with R-CDs show that the CDs could pass through the cell wall into the cell and reach the nucleus. The cell wall and the nucleus could be clearly visualized. CDs also shows low toxicity to human bronchial epithelial cells (BEAS-2B) with good biological activity. The obtained results indicate that the CDs and R-CDs have good fluorescent property which could be used as bio-imaging agent.

Optimizing immunostaining of archival fish samples to enhance museum collection potential.

Immunohistochemistry (IHC) is a powerful biochemical technique that uses antibodies to specifically label and visualize proteins of interests within biological samples. However, fluid-preserved specimens within natural history collection often use fixatives and protocols that induce high background signal (autofluorescence), which hampers IHC as it produces low signal-to-noise ratio. Here, we explored techniques to reduce autofluorescence using sodium borohydride (SBH), citrate buffer, and their combination on fish tissue preserved with paraformaldehyde, formaldehyde, ethanol, and glutaraldehyde. We found SBH was the most effective quenching technique, and applied this pretreatment to the gill or skin of 10 different archival fishes - including specimens that had been preserved in formaldehyde or ethanol for up to 65 and 37 years, respectively. The enzyme Na+/K+-ATPase (NKA) was successfully immunostained and imaged using confocal fluorescence microscopy, allowing for the identification and characterization of NKA-rich ionocytes essential for fish ionic and acid-base homeostasis. Altogether, our SBH-based method facilitates the use of IHC on archival samples, and unlocks the historical record on fish biological responses to environmental factors (such as climate change) using specimens from natural history collections that were preserved decades to centuries ago.

Understanding the Behaviour of Real Metaborates in Solution.

Alkali metal borohydrides are promising candidates for large-scale hydrogen storage. They react spontaneously with water, generating dihydrogen and metaborate salts. While sodium borohydride is the most studied, potassium has the best chance of commercial application. Here we examine the physical and chemical properties of such self-hydrolysis solutions. We do this by following the hydrogen evolution, the pH changes, and monitoring the reaction intermediates using NMR. Most studies on such systems are done using dilute solutions, but real-life applications require high concentrations. We show that increasing the borohydride concentration radically changes the system's microstructure and rheology. The changes are seen already at concentrations as low as 5 w/w%, and are critical above 10 w/w%. While dilute solutions are Newtonian, concentrated reaction solutions display non-Newtonian behaviour, that we attribute to the formation and (dis)entanglement of metaborate oligomers. The implications of these findings towards using borohydride salts for hydrogen storage are discussed.

Nanofluidic Trapping of Faceted Colloidal Nanocrystals for Parallel Single-Particle Catalysis.

Catalyst activity can depend distinctly on nanoparticle size and shape. Therefore, understanding the structure sensitivity of catalytic reactions is of fundamental and technical importance. Experiments with single-particle resolution, where ensemble-averaging is eliminated, are required to study it. Here, we implement the selective trapping of individual spherical, cubic, and octahedral colloidal Au nanocrystals in 100 parallel nanofluidic channels to determine their activity for fluorescein reduction by sodium borohydride using fluorescence microscopy. As the main result, we identify distinct structure sensitivity of the rate-limiting borohydride oxidation step originating from different edge site abundance on the three particle types, as confirmed by first-principles calculations. This advertises nanofluidic reactors for the study of structure-function correlations in catalysis and identifies nanoparticle shape as a key factor in borohydride-mediated catalytic reactions.

Cloning and Characterization of Fructose-1,6-Bisphosphate Aldolase from Euphausia superba.

Fructose-1,6-bisphosphate aldolase (EC 4.1.2.13) is a highly conserved enzyme that is involved in glycolysis and gluconeogenesis. In this study, we cloned the fructose-1,6-bisphosphate aldolase gene from Euphausia superba (EsFBA). The full-length cDNA sequence of EsFBA is 1098 bp long and encodes a 365-amino-acid protein. The fructose-1,6-bisphosphate aldolase gene was expressed in Escherichia coli (E. coli). A highly purified protein was obtained using HisTrap HP affinity chromatography and size-exclusion chromatography. The predicted three-dimensional structure of EsFBA showed a 65.66% homology with human aldolase, whereas it had the highest homology (84.38%) with the FBA of Penaeus vannamei. Recombinant EsFBA had the highest activity at 45 °C and pH 7.0 in phosphate buffer. By examining the activity of metal ions and EDTA, we found that the effect of metal ions and EDTA on EsFBA's enzyme activity was not significant, while the presence of borohydride severely reduced the enzymatic activity; thus, EsFBA was confirmed to be a class I aldolase. Furthermore, targeted mutations at positions 34, 147, 188, and 230 confirmed that they are key amino acid residues for EsFBA.

In-situ formed nanoscale Fe0 for fenton-like oxidation of thermosetting unsaturated polyester resin composites: Nondestructively recycle carbon fiber.

Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H2O2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.

Multispectroscopic studies on the molecular interactions between bovine γ-globulin and borohydride-capped silver nanoparticles.

Interactions between bovine γ-globulin (BGG) and borohydride-capped silver nanoparticles (BAgNPs) were studied using dynamic light scattering (DLS) and spectroscopic techniques such as UV-vis spectroscopy, fluorescence, and circular dichroism. The results were compared with earlier reported interactions between γ-globulin and citrate-coated AgNPs (CAgNPs). BAgNPs were synthesized and characterized. Irrespective of the coating on AgNPs, nanoparticles had formed ground-state complexes with the protein. CAgNPs, as well as BAgNPs had caused static quenching of tryptophan (Trp) fluorescence of the protein. The change in the capping agent from citrate to borohydride weakened the binding of nanoparticles with the protein. But the same change in capping agent had increased the fluorescence quenching efficiency of AgNPs. Hydrogen bonding and van der Waals interactions were involved in BGG-BAgNPs complex similar to the CAgNPs complex with γ-globulin. Polarity of the Trp microenvironment in BGG was not altered using BAgNPs as opposed to CAgNPs, as supported using synchronous and three-dimensional fluorescence. Resonance light scattering experiments also suggested nano-bio conjugation. Far-UV and near-UV circular dichroism (CD) spectra respectively pointed towards changes in the secondary and tertiary structure of BGG by BAgNPs, which was not observed for CAgNPs.

Hydrolysis of the Borohydride Anion BH4-: A 11B NMR Study Showing the Formation of Short-Living Reaction Intermediates including BH3OH.

In hydrolysis and electro-oxidation of the borohydride anion BH4-, key reactions in the field of energy, one critical short-living intermediate is BH3OH-. When water was used as both solvent and reactant, only BH3OH- is detected by 11B NMR. By moving away from such conditions and using DMF as solvent and water as reactant in excess, four 11B NMR quartets were observed. These signals were due to BH3-based intermediates as suggested by theoretical calculations; they were DMF·BH3, BH3OH-, and B2H7- (i.e., [H3B-H-BH3]- or [H4B-BH3]-). Our results shed light on the importance of BH3 stemming from BH4- and on its capacity as Lewis acid to interact with Lewis bases such as DMF, OH-, and BH4-. These findings are important for a better understanding at the molecular level of hydrolysis of BH4- and production of impurities in boranes synthesis.

Rare Earth Starting Materials and Methodologies for Synthetic Chemistry.

The number of rare earth (RE) starting materials used in synthesis is staggering, ranging from simple binary metal-halide salts to borohydrides and "designer reagents" such as alkyl and organoaluminate complexes. This review collates the most important starting materials used in RE synthetic chemistry, including essential information on their preparations and uses in modern synthetic methodologies. The review is divided by starting material category and supporting ligands (i.e., metals as synthetic precursors, halides, borohydrides, nitrogen donors, oxygen donors, triflates, and organometallic reagents), and in each section relevant synthetic methodologies and applications are discussed.

Borohydride and metallic copper as a robust dehalogenation system: Selectivity assessment and system optimization.

Hydrodechlorination (HDC) using noble-metal catalysts in the presence of H-donors is a promising tool for the treatment of water contaminated by halogenated organic compounds (HOCs). Cu is an attractive alternative catalyst to noble metals since it is cheaper than Pd, Rh, or Pt and more stable against deactivation. Cu with borohydride (BH4-) as reductant (copper-borohydride reduction system; CBRS) was applied here for the treatment of saturated aliphatic HOCs. The HDC ability of CBRS was evaluated based upon product selectivities during reduction of CCl3-R compounds (R = H, F, Cl, Br, and CH3). For CHCl3, CH2Cl2, and CHCl2-CH3, the dechlorination reaction proceeds predominantly via α-elimination with initial product selectivities to CH4 and C2H6 of 84-85 mol-% and 70-72 mol-%. For CCl4, CBrCl3, CFCl3, and CCl3-CH3, stepwise hydrogenolysis dominates. CH2Cl-R compounds are formed as recalcitrant intermediates with initial selectivities of 50-72 mol-%, whereas CH4 and C2H6 are minor products with 16-35 mol-% and 30-35 mol-%. The effect of reaction conditions on product selectivities were investigated for CHCl3 as target. Solution composition, variation of reducing agents (BH4-, H* from H2) and increase of electron pressure (electric potential at Cu electrode and Fe0 as support) did not have marked influence on the selectivities (ratio of CH4 : CH2Cl2). Product selectivities for reduction of CCl3-R compounds were found to be substrate-specific rather than reductant-specific. Since the formation of halogenated by-products could not be avoided, transformation via a second reduction step was optimized by higher catalyst dose, addition of Ag, and vitamin B12 to the CBRS. Comparison between Pd and Cu based on costs, catalyst activities, selectivities, metal stability, and fate of halogenated by-products shows that the CBRS is a potent alternative to conventional HDC catalysts and can be recommended as 'agent of choice' for treatment of α-substituted haloalkanes in heavily contaminated waters.

Pyridine Borane as Alternative Reducing Agent to Sodium Cyanoborohydride for the PEGylation of L-asparaginase.

PEGylation is a reductive alkylation of a protein N-terminal/α-amine of protein with mPEG chain by reducing agent. To obtain quantitative and site-specific PEGylation, sodium cyanoborohydride is commonly used as a reducing agent. The reduction process of sodium cyanoborohydride produces highly poisonous hydrogen cyanide, which may render the final product toxic. Herein, we have studied various reducing agents such as dimethylamine borane, triethylamine borane, trimethylamine borane, pyridine borane, morpholine borane, 2-picoline borane, and 5-ethyl-2-methyl-pyridine borane were tested as alternatives to sodium cyanoborohydride for the PEGylation of L-asparaginase. The characterization of reacted pegaspargase was carried out by SDS-PAGE, Western blotting, SEC-HPLC, RP-HPLC, SEC-MALS, CD, enzyme activity, and cell proliferation assays using with lymphoblast cells and MTS/PMS as substrate. Pyridine borane was determined to be the best acceptable reducing agent for PEGylation in terms of purity and activity. As a result, instead of sodium cyanoborohydride, pyridine borane can be employed.

Paving the Way to the Fuel of the Future-Nanostructured Complex Hydrides.

Hydrides have emerged as strong candidates for energy storage applications and their study has attracted wide interest in both the academic and industry sectors. With clear advantages due to the solid-state storage of hydrogen, hydrides and in particular complex hydrides have the ability to tackle environmental pollution by offering the alternative of a clean energy source: hydrogen. However, several drawbacks have detracted this material from going mainstream, and some of these shortcomings have been addressed by nanostructuring/nanoconfinement strategies. With the enhancement of thermodynamic and/or kinetic behavior, nanosized complex hydrides (borohydrides and alanates) have recently conquered new estate in the hydrogen storage field. The current review aims to present the most recent results, many of which illustrate the feasibility of using complex hydrides for the generation of molecular hydrogen in conditions suitable for vehicular and stationary applications. Nanostructuring strategies, either in the pristine or nanoconfined state, coupled with a proper catalyst and the choice of host material can potentially yield a robust nanocomposite to reliably produce H2 in a reversible manner. The key element to tackle for current and future research efforts remains the reproducible means to store H2, which will build up towards a viable hydrogen economy goal. The most recent trends and future prospects will be presented herein.

Response of Normal Tissues to Boron Neutron Capture Therapy (BNCT) with 10B-Borocaptate Sodium (BSH) and 10B-Paraboronophenylalanine (BPA).

Boron neutron capture therapy (BNCT) is a cancer-selective radiotherapy that utilizes the cancer targeting 10B-compound. Cancer cells that take up the compound are substantially damaged by the high liner energy transfer (LET) particles emitted mainly from the 10B(n, α7Li reaction. BNCT can minimize the dose to normal tissues, but it must be performed within the tolerable range of normal tissues. Therefore, it is important to evaluate the response of normal tissues to BNCT. Since BNCT yields a mixture of high and low LET radiations that make it difficult to understand the radiobiological basis of BNCT, it is important to evaluate the relative biological effectiveness (RBE) and compound biological effectiveness (CBE) factors for assessing the responses of normal tissues to BNCT. BSH and BPA are the only 10B-compounds that can be used for clinical BNCT. Their biological behavior and cancer targeting mechanisms are different; therefore, they affect the CBE values differently. In this review, we present the RBE and CBE values of BPA or BSH for normal tissue damage by BNCT irradiation. The skin, brain (spinal cord), mucosa, lung, and liver are included as normal tissues. The CBE values of BPA and BSH for tumor control are also discussed.

Antibacterial and Antifungal Properties of Silver Nanoparticles-Effect of a Surface-Stabilizing Agent.

The biocidal properties of silver nanoparticles (AgNPs) prepared with the use of biologically active compounds seem to be especially significant for biological and medical application. Therefore, the aim of this research was to determine and compare the antibacterial and fungicidal properties of fifteen types of AgNPs. The main hypothesis was that the biological activity of AgNPs characterized by comparable size distributions, shapes, and ion release profiles is dependent on the properties of stabilizing agent molecules adsorbed on their surfaces. Escherichia coli and Staphylococcus aureus were selected as models of two types of bacterial cells. Candida albicans was selected for the research as a representative type of eukaryotic microorganism. The conducted studies reveal that larger AgNPs can be more biocidal than smaller ones. It was found that positively charged arginine-stabilized AgNPs (ARGSBAgNPs) were the most biocidal among all studied nanoparticles. The strongest fungicidal properties were detected for negatively charged EGCGAgNPs obtained using (-)-epigallocatechin gallate (EGCG). It was concluded that, by applying a specific stabilizing agent, one can tune the selectivity of AgNP toxicity towards desired pathogens. It was established that E. coli was more sensitive to AgNP exposure than S. aureus regardless of AgNP size and surface properties.

Effect of silver nanoparticles on the antibacterial activity of Levofloxacin against methicillin-resistant Staphylococcus aureus.

OBJECTIVE: The paper presents the antibacterial activity of silver nanoparticles (AgNPs) when conjugated with Levofloxacin. The AgNPs used in this study were synthesized from silver nitrate using sodium borohydride as a reducing agent. MATERIALS AND METHODS: Levofloxacin activity was determined by minimum inhibitory concentrations (MICs) and also the erythrocyte hemolytic assay determined the capability of conjugation to cause hemolysis in human erythrocyte. RESULTS: The synthesis of levofloxacin-AgNP conjugates was confirmed by ultraviolet/visible (UV/vis) spectroscopy. A peak absorption value between 400-450 nm for the extract and the color change to dark brown were corresponding to the plasmon absorbance of AgNPs. On the other hand, levofloxacin-AgNPs could be effective against methicillin-resistant Staphylococcus aureus (MRSA). The MICs of levofloxacin and levofloxacin-AgNPs were 12 and 10 µM, respectively. CONCLUSIONS: These findings indicated that levofloxacin-AgNPs had an effective bactericidal activity against the bacterial MRSAs. This conjugation appeared to inhibit bacterial adaptive capabilities, which leads to inhibition of bacterial resistance.