Physical Properties, Chemical Analysis, and Evaluation of Antimicrobial Response of New Polylactide/Alginate/Copper Composite Materials.

In recent years, due to an expansion of antibiotic-resistant microorganisms, there has been growing interest in biodegradable and antibacterial polymers that can be used in selected biomedical applications. The present work describes the synthesis of antimicrobial polylactide-copper alginate (PLA-ALG-Cu2+) composite fibers and their characterization. The composites were prepared by immersing PLA fibers in aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the polylactide fibers with Cu(II) ions to yield PLA-ALG-Cu2+ composite fibers. The composites, so prepared, were characterized by scanning electron microscopy (SEM), UV/VIS transmittance and attenuated total reflection Fourier-transform infrared spectroscopy ATR-FTIR, and by determination of their specific surface area (SSA), total/average pore volumes (through application of the 5-point Brunauer-Emmett-Teller method (BET)), and ability to block UV radiation (determination of the ultraviolet protection factor (UPF) of samples). The composites were also subjected to in vitro antimicrobial activity evaluation tests against colonies of Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria and antifungal susceptibility tests against Aspergillus niger and Chaetomium globosum fungal mold species. All the results obtained in this work showed that the obtained composites were promising materials to be used as an antimicrobial wound dressing.

Application of Biocides and Super-Absorbing Polymers to Enhance the Efficiency of Filtering Materials.

Studies on the functionalization of materials used for the construction of filtering facepiece respirators (FFRs) relate to endowing fibers with biocidal properties. There is also a real need for reducing moisture content accumulating in such materials during FFR use, as it would lead to decreased microorganism survival. Thus, in our study, we propose the use of superabsorbent polymers (SAPs), together with a biocidal agent (biohalloysite), as additives in the manufacturing of polypropylene/polyester (PP/PET) multifunctional filtering material (MFM). The aim of this study was to evaluate the MFM for stability of the modifier's attachment to the polymer matrix, the degree of survival of microorganisms on the nonwoven, and its microorganism filtration efficiency. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to test the stability of the modifier's attachment. The filtration efficiency was determined under conditions of dynamic aerosol flow of S. aureus bacteria. The survival rates (N%) of the following microorganisms were assessed: Escherichia coli and Staphylococcus aureus bacteria, Candida albicans yeast, and Aspergillus niger mold using the AATCC 100-2004 method. FTIR spectrum analysis confirmed the pre-established composition of MFM. The loss of the active substance from MFM in simulated conditions of use did not exceed 0.02%, which validated the stability of the modifier's attachment to the PP/PET fiber structure. SEM image analysis verified the uniformity of the MFM structure. Lower microorganism survival rates were detected for S. aureus, C. albicans, and E. coli on the MFM nonwoven compared to control samples that did not contain the modifiers. However, the MFM did not inhibit A. niger growth. The MFM also showed high filtration efficiency (99.86%) against S. aureus bacteria.

Antibacterial and antifungal activity of chitosan coated iron oxide nanoparticles.

BACKGROUND AND AIM: The emergence of resistance against antimicrobial agents has led to the development of more efficient agents and new techniques for treatment of various microbial infections. The aim of the present study is to determine the antibacterial and antifungal activity of bare and chitosan coated Fe3O4 nanoparticles (NPs) against five organisms, Escherichia coli (E. coli), Bacillus subtilis (B. subtilis), Candida albicans (C. albicans), Aspergillus niger (A. niger) and Fusarium solani (F. solani). METHODS: Fe3O4 NPs were synthesised by coprecipitation and surface coating was done by chitosan polymer to avoid agglomeration. The antimicrobial property of NPs was tested by agar well diffusion and analysed by measuring the diameter of the inhibition zone. RESULTS: Average particle size of Fe3O4 and chitosan coated Fe3O4 NPs was 10.4 ± 4.9 and 11.4 ± 5.2 nm, respectively. Mean diameter of inhibition zone of synthesised chitosan coated Fe3O4 NPs was in the range 14.5 to 18.5 mm. The effect of chitosan coated Iron oxide nanoparticles was F. solani/A. niger < C. albicans < E. coli/B. subtilis (p < 0.001). CONCLUSIONS: Chitosan coated Fe3O4 NPs are effective antimicrobial agents and so may be developed as a microbial resistant coating for biomedical devices.

Development of topical hydrogels of terbinafine hydrochloride and evaluation of their antifungal activity.

The purpose of this study was to prepare hydrogels and microemulsion (ME)-based gel formulations containing 1% terbinafine hydrochloride (TER-HCL) and to evaluate the use of these formulations for the antifungal treatment of fungal infections. Three different hydrogel formulations were prepared using chitosan, Carbopol® 974 and Natrosol® 250 polymers. A pseudo-ternary phase diagram was constructed, and starting from ME formulation, a ME gel form containing 1% Carbopol 974 was prepared. We also examined the characteristic properties of the prepared hyrogels. The physical stability of hydrogels and the ME -based gels were evaluated after storage at different temperatures for a period of 3 months. The release of TER-HCL from the gels and the commercial product (Lamisil®) was carried out by using a standard dialysis membrane in phosphate buffer (pH 5.2) at 32 °C. The results of the in vitro release study showed that the Natrosol gel released the highest amount of drug, followed by Carbopol gel, chitosan gel, commercial product, and the microoemulsion-based gel in that order. In vitro examination of antifungal activity revealed that all the prepared and commercial products were effective against Candida parapsilosis, Penicillium, Aspergillus niger and Microsporum. These results indicate that the Natrosol®-based hydrogel is a good candidate for the topical delivery of TER-HCL.

Purification and characterization of three ß-glycosidases exhibiting high glucose tolerance from Aspergillus niger ASKU28.

Production and utilization of cellulosic ethanol has been limited, partly due to the difficulty in degradation of cellulosic feedstock. ß-Glucosidases convert cellobiose to glucose in the final step of cellulose degradation, but they are inhibited by high concentrations of glucose. Thus, in this study, we have screened, isolated, and characterized three ß-glycosidases exhibiting highly glucose-tolerant property from Aspergillus niger ASKU28, namely ß-xylosidase (P1.1), ß-glucosidase (P1.2), and glucan 1,3-ß-glucosidase (P2). Results from kinetic analysis, inhibition study, and hydrolysis of oligosaccharide substrates supported the identification of these enzymes by both LC/MS/MS analysis and nucleotide sequences. Moreover, the highly efficient P1.2 performed better than the commercial ß-glucosidase preparation in cellulose saccharification, suggesting its potential applications in the cellulosic ethanol industry. These results shed light on the nature of highly glucose-tolerant ß-glucosidase activities in A. niger, whose kinetic properties and identities have not been completely determined in any prior investigations.

The effect of spent coffee ground (SCG) loading, matrix ratio and biological treatment of SCG on poly(hydroxybutyrate) (PHB)/poly(lactic acid) (PLA) polymer blend.

This study investigates the effects of SCG embedded into biodegradable polymer blends and aimed to formulate and characterise biomass-reinforced biocomposites using spent coffee ground (SCG) as reinforcement in PHB/PLA polymer blend. The effect of SCG filler loading and varying PHB/PLA ratios on the tensile properties and morphological characteristics of the biocomposites were examined. The results indicated that tensile properties reduction could be due to its incompatibility with the PHB/PLA matrixSCG aggregation at 40 wt% content resulted in higher void formation compared to lower content at 10 wt%. A PHB/PLA ratio of 50/50 with SCG loading 20 wt% was chosen for biocomposites with treated SCG. Biological treatment of SCG using Phanerochaete chrysosporium CK01 and Aspergillus niger DWA8 indicated P. chrysosporium CK01 necessitated a higher moisture content for optimum growth and enzyme production, whereas the optimal conditions for enzyme production (50-55 %, w/w) differed from those promoting A. niger DWA8 growth (40 %, w/w). SEM micrographs highlighted uniform distribution and effective wetting of treated SCG, resulting in improvements of tensile strength and modulus of biocomposites, respectively. The study demonstrated the effectiveness of sustainable fungal treatment in enhancing the interfacial adhesion between treated SCG and the PHB/PLA matrix.

Time-kill kinetic of nano-ZnO-loaded nanoliposomes against Aspergillus niger and Botrytis cinerea.

In vitro antimicrobial activity of nano-ZnO-loaded nanoliposomes at different levels of lecithin:nano-ZnO ratio (5:1, 15:1, and 25:1 w/w) against Aspergillus niger (IBRC-M 30095) and Botrytis cinerea (IBRC-M 30162) was evaluated. Nanoliposome formulations containing nano-ZnO were fabricated through thin-layer hydration sonication and heat methods. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of nano-ZnO-loaded nanoliposomes and free nano-ZnO against Aspergillus niger and Botrytis cinerea were determined. The time-kill experiments were performed for each isolate. Results showed that the encapsulation of nano-ZnO in nanoliposome systems significantly enhanced their antimicrobial activities by improving the penetration of ZnO nanoparticles the fungi cell membrane. In vitro antifungal activity of nano-ZnO-loaded nanoliposomes against Aspergillus niger and Botrytis cinerea was increased in thin-layer hydration sonication method compared with the heat method. The log phase for Aspergillus niger and Botrytis cinerea was around 70 h. Adding nano-ZnO-loaded nanoliposomes to the culture medium shortened the log phase for both Aspergillus niger and Botrytis cinerea. The highest antimicrobial activity of nanoliposomes was achieved using nanoliposomes containing the lecithin:nano-ZnO ratio of 25:1 (w/w) as compared to all samples. However, the length of the log phase growth cultures exposed to the nanoliposome formulations prepared by thin-layer hydration sonication method with the lecithin:nano-ZnO ratio of 25:1 (w/w) at MIC and MFC values was 60 and 40 h for both Aspergillus niger and Botrytis cinerea, respectively.

Poly-(lactic acid) composite films comprising carvacrol and cellulose nanocrystal-zinc oxide with synergistic antibacterial effects.

Herein, carvacrol (CRV) and modified cellulose nanocrystal-zinc oxide (CNC-ZnO) were incorporated into a poly (lactic acid) (PLA) matrix to prepare a PLA-based composite film using a simple solution casting method to achieve antimicrobial effects for application in antimicrobial food packaging. Compared with films obtained from neat PLA, the PLA@CRV20%@CNC-ZnO3% composite film shows better performance in terms of mechanical properties, ultraviolet (UV) blocking, and antimicrobial effects. The PLA composites containing CRV and 3 wt% CNC-ZnO blends exhibit improved tensile strength (21.8 MPa) and elongation at break (403.1 %) as well as excellent UV resistance. In particular, CRV and the CNC-ZnO hybrid endow the obtained PLA composite films with a synergistic antibacterial effect, resulting in good antibacterial properties for microbes, such as Escherichia coli, Staphylococcus aureus and Aspergillus niger. The diameters of the inhibition zone of the PLA@CRV20%@CNC-ZnO3% composite films against E. coli, S. aureus, and A. niger were 4.9, 5.0, and 3.4 cm, respectively. Appling the PLA@CRV20%@CNC-ZnO3% composite film as an antibacterial food packaging material, the storage period for strawberries was considerably extended. This study provides a theoretical basis for developing new organic/inorganic composite antimicrobial film materials from PLA.

New alkaloid from Streptomyces koyangensis residing in Odontotermes formosanus.

A new alkaloid was isolated from the ethyl acetate extract of the culture of a termite-associated Streptomyces koyangensis BY-4. The structure of 1 was elucidated by using MS, NMR, electronic circular dichroism data, and computational approaches. Compound 1 showed weak antimicrobial activities against a panel of test microbes.

Microwave assisted dyeing of polyester fabrics with disperse dyes.

Dyeing of polyester fabrics with thienobenzochromene disperse dyes under conventional and microwave heating conditions was studied in order to determine whether microwave heating could be used to enhance the dyeability of polyester fabrics. Fastness properties of the dyed samples were measured. All samples dyed with or without microwave heating displayed excellent washing and perspiration fastness. The biological activities of the synthesized dyes against Gram positive bacteria, Gram negative bacteria, yeast and fungus were also evaluated.

Conjugated polymers for light-activated antifungal activity.

A cationic polythiophene-porphyrin (PTP) dyad is shown to exhibit efficient light-activated antifungal activity. Higher singlet oxygen (¹O2) generation efficiency can be attained from PTP upon photoexcitation due to the light-harvesting properties of the polymer backbone and efficient energy transfer from the polythiophene to the porphyrin units. PTP can be used for treating fungal infections in lower doses of irradiation light and polymer concentration.

Surface-modified sulfur nanoparticles: an effective antifungal agent against Aspergillus niger and Fusarium oxysporum.

Surface-modified sulfur nanoparticles (SNPs) of two different sizes were prepared via a modified liquid-phase precipitation method, using sodium polysulfide and ammonium polysulfide as starting material and polyethylene glycol-400 (PEG-400) as the surface stabilizing agent. Surface topology, size distribution, surface modification of SNPs with PEG-400, quantitative analysis for the presence of sulfur in nanoformulations, and thermal stability of SNPs were determined by atomic force microscopy (AFM), dynamic light scattering (DLS) plus high-resolution transmission electron microscopy (HR-TEM), fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX) spectroscopy, and thermogravimetric analysis (TGA), respectively. A simultaneous study with micron-sized sulfur (S(0)) and SNPs was carried out to evaluate their fungicidal efficacy against Aspergillus niger and Fusarium oxysporum in terms of radial growth, sporulation, ultrastructural modifications, and phospholipid content of the fungal strains using a modified poisoned food technique, spore-germination slide bioassay, environmental scanning electron microscopy (ESEM), and spectrometry. SNPs expressed promising inhibitory effect on fungal growth and sporulation and also significantly reduced phospholipid content.

Anti-fungal effect of Hevea brasiliensis latex C-serum on Aspergillus niger.

OBJECTIVES: Hevea brasiliensis extract could potentially be employed as a relatively low cost resource for various anti-fungal activities due to the simplicity of latex preparation and the abundance of latex that can be obtained in rubber producing regions. The present study was aimed at examining the species specific anti-fungal property of H. brasilensis latex C-serum against Aspergillus niger. RESULTS: The results showed that the latex C-serum exerted a specific antifungal activity against Aspergillus niger, but not Candida albicans. Low toxicity of the C-serum was demonstrated in Brine Shrimp Lethality Test (BSLT) with an LC50 value of 98.4 mg/ml. CONCLUSIONS: Pending further more elaborated investigations, H. brasiliensis latex C-serum, with its species specific anti-fungal and cancer-origin cell line specific anti-proliferation properties, would probably contribute in healthcare in addition to its traditional role in polymer industry.

Electrospun ethyl cellulose/poly caprolactone/gelatin nanofibers: The investigation of mechanical, antioxidant, and antifungal properties for food packaging.

The purpose of the present research was to fabricate ethylcellulose (ECL)/polycaprolactone (PCL)/gelatin (GEL) electrospun nanofibers containing Zataria multiflora essential oil (ZEO) and zinc oxide nanoparticle (ZnO) to provide an appropriate substrate for food packaging. The ECL/PCL/GEL was incorporated with ZEO and ZnO at the concentrations of 10, 20, 30 and 50 wt% and 3 wt%, respectively. The results of ECL/PCL/GEL/ZEO/ZnO nanofiber exhibited uniform morphology with a mean diameter ranging from 361.85 ± 18.7 to 467.33 ± 14.50 nm and enhanced thermal stability. The ECL/PCL/GEL/ZEO/ZnO nanofiber had the highest mechanical parameters, such as young's modulus (437.49 ± 18), tensile strength (7.88 ± 0.7), and elongation at break (5.02 ± 0.6) and water contact angle (61.13 ± 0.5), compared with the other nanofibers. The cell viability during 48 and 72 h was obtained to be about more than 80% for all the nanofibers. Additionally, the ECL/PCL/GEL incorporated with 50% ZEO and 3% ZnO displayed the highest antioxidant activity (34.61 ± 1.98%) and antifungal properties against Penicillium notatum and Aspergillus niger. In general, the ECL/PCL/GEL with the weight ratio of 20:70:10 nanofiber incorporated with 30% ZEO and 3% ZnO was obtained to have appropriate mechanical, antioxidant, and antimicrobial properties and thermal stability.

Formulation and evaluation of butenafine loaded PLGA-nanoparticulate laden chitosan nano gel.

The present research work is designed to prepare and optimize butenafine (BT) loaded poly lactic co glycolic acid (PLGA) nanoparticles (BT-NPs). BT-NPs were prepared by emulsification probe sonication method using PLGA (A), PVA (B) as polymer and stabilizer, respectively. The optimum composition of BT-NPs was selected based on the point prediction method given by the Box Behnken design software. The optimized composition of BT-NPop showed a particle size of 267.21 ± 3.54 nm with an entrapment efficiency of 72.43 ± 3.11%. The optimum composition of BT-NPop was further converted into gel formulation using chitosan as a natural polymer. The prepared topical gel formulation (BT-NPopG) was further evaluated for gel characterization, drug release, permeation study, irritation, and antifungal studies. The prepared BT-NPopG formulation showed optimum pH, viscosity, spreadability, and drug content. The release and permeation study results revealed slow BT release (42.76 ± 2.87%) with significantly enhanced permeation across the egg membrane. The irritation study data showed negligible irritation with a cumulative score of 0.33. The antifungal study results conclude higher activity than marketed as well as pure BT. The overall conclusion of the results revealed BT-NPopG as an ideal delivery system to treat topical fungal infection.

Antimicrobial Imperata cylindrica paper coated with anionic nanocellulose crosslinked with cationic ions.

Recently, the interest in active packaging utilization has increased with population growth, food demand and new consumer trend like food delivery services. This new system, however, requires the use of additives to extend the food product quality and safety as well as in maintaining the shelf-life. This study was to prepare the antimicrobial paper from I. cylindrica coated anionic nanocellulose crosslinked cationic to create a system with the ability to actively control microbe growth in the packaging materials. The process involved pulping of I. cylindrica using semi-chemical and soda chemical method. The antimicrobial paper was prepared by printing the pulp suspension in 60 g/m2 grammage in mold followed by the spray of anionic nanocellulose and subsequent soaking of the paper in cationic solution. The results showed the I. cylindrica paper coated anionic nanocellulose crosslinked with H+ and Al3+ cations were successfully produced. The paper produced was also observed to have antimicrobial activity against Gram-negative of E. coli and S. typhi as well as Gram-positive of S. aureus and B. subtilis bacteria. Furthermore, the best coating method was found on antimicrobial paper coated anionic nanocellulose crosslinked Al3+ as evidenced by smoother and compact surface structure.

A novel chitosan biopolymer based Trichoderma delivery system: Storage stability, persistence and bio efficacy against seed and soil borne diseases of oilseed crops.

Management of seed and soil borne fungal plant pathogens using fungal species belonging to the genus Trichoderma is gaining importance. Seed coating with powder based formulations of Trichoderma is most widely adopted by the researchers and farmers as well. Delivery system that leads to good adherence of fungal propagules on seed surface, minimizing the wastage of active ingredient, sustained and timely release during treatment process is very important for effective season long protection. Chitosan-PEG (Polyethylene glycol) (Cts-PEG) blend containing Trichoderma harzianum (Th4d) (Cts-PEG-Th) spores is developed and its storage stability, persistence in soil and bio efficacy against seed and soil borne pathogens of groundnut and safflower crops is studied. The blend was stable without much changes in pH throughout the storage period. Persistence studies conducted for 3 months revealed that Cts-PEG-Th amended soil, Trichoderma got released from polymer film slowly and reached a maximum of log 8 CFUs by 30 days and there after started declining to retain log 6 CFUs at 90 days. In shelf life study, the chitosan blend was able to maintain Trichoderma counts of log 10.0 and log 10.2 over a period of 6 months at storage temperatures of 30 °C and 4 °C, respectively and the antagonistic activity unaffected against three plant pathogens viz. Macrophomina phaseolina, Fusarium oxysporumf. sp.ricini and Aspergillus niger over a period of 6 months of storage. Bio efficacy testing in germination towels and green house pot studies revealed the effectiveness of seed treatment with Cts-PEG-Th blend significantly increasing the germination and seedling vigour and reducing the diseases in groundnut (peanut) and safflower.

Kolliphor® HS 15-cyclodextrin Complex for the Delivery of Voriconazole: Preparation, Characterization, and Antifungal Activity.

BACKGROUND: This study aimed to reduce the amount of sulfobutylether-ß-cyclodextrin (SBECD) used in the marketed voriconazole injections to meet the clinical needs of patients with moderate-to-severe renal impairment (creatinine clearance rate <50 mL/min). OBJECTIVE: This study found that the surfactant Kolliphor® HS 15 (HS 15) and SBECD had significant synergistic effects on solubilizing voriconazole, and a novel voriconazole complex delivery system (VRC-CD/HS 15) was established. METHODS: The complex system was characterized, and its antifungal activity was studied by dynamic light scattering, dialysis bag method, disk diffusion, and broth microdilution. RESULTS: Compared with the control, its encapsulation efficiency (90.07±0.48%), drug loading (7.37±0.25%) and zeta potential (-4.36±1.37 mV) were increased by 1.54%, 41.19%, and 296.36%, respectively; its average particle size (13.92±0.00 nm) was reduced by 15.69%, so the complex system had better stability. Simultaneously, its drug release behavior was similar to that of the control, and it was a first-order kinetic model. Antifungal studies indicated that the complex system had noticeable antifungal effects. With the increase of drug concentration, the inhibition zone increased. The minimum inhibitory concentrations of the complex system against Cryptococcus neoformans, Aspergillus niger and Candida albicans were 0.0313 µg/mL, 1 µg/mL and 128 µg/mL, respectively. CONCLUSION: It showed a significant inhibitory effect on C. neoformans and had a visible therapeutic effect on Kunming mice infected with C. neoformans. Consequently, VRC-CD/HS 15 had better physicochemical properties and still had an apparent antifungal effect, and was promising as a potential alternative drug for clinical application.

In situ synthesis of Fe3O4@ cyanoethyl cellulose composite as antimicrobial and semiconducting film.

Cyanoethyl cellulose (CEC)/ magnetite (Fe3O4) flexible composite film with enhanced dielectric and magnetic properties was successfully prepared. CEC has been synthesized from micro crystalline cellulose (MCC). The effects of magnetite mass fraction on the morphology, microstructure, thermal stability, and antimicrobial activity of the as-prepared composite films were investigated. The Vibrating sample magnetometer (VSM) and broadband dielectric spectrometer was also employed to study the magnetic and dielectric properties, respectively. In addition to study the computational calculation of MCC, and CEC by DFT/ B3LYP/6-31G (d) basis sets. The results showed that, the sample that is magnetite free has a diamagnetic response to the applied magnetic field, however the other samples that is loaded with magnetite show super-paramagnetic behavior indicating that the particles' sizes of the magnetite mostly below 20 nm. Also, antimicrobial activities of composite films against (G + ve), (G-ve), were investigated.

Synthesis, antimicrobial activity, and sustainable release of novel α-aminophosphonate derivatives loaded carrageenan cryogel.

Novel α-aminophosphonates 4 were synthesized via one pot three-component reaction of 4-aminoantipyrine, aldehydes, triphenylphosphite and Lewis acid catalyst. The chemical structures of all the synthesized compounds were elucidated by IR, NMR and MS spectral analysis. The antimicrobial activity of 4 was tested in vitro against pathogenic microbes such as E.coli, S.aureus, A.niger and C.albicans. Three of them (4f-h) exhibited high antimicrobial activity and were loaded to carrageenan cryogel for drug delivery studies. With the aid of cellulose nanofibrils (CNF) as reinforcing material and glyoxal as a cross-linking agent, porous cryogels with improved mechanical properties were obtained. Among all, CAR-7 presents the optimum cryogel sample, which contained around 16% CNF and 0.2 mL/15 mL polymer blend. CAR-7 demonstrated highest mechanical compressive strength, porosity (80%), and swelling capacity (75%). Sustainable release behavior over 24 h was observed for the loaded cryogels. The antimicrobial activity of cryogels against S.aureus showed marginal differences between samples. CAR-9 (loaded with 4f) showed the highest reduction percentage in number of bacterial colonies (99.94%) followed by CAR-11 (loaded with 4h, 99.3%) and finally CAR-10 (loaded with 4g, 99.29%).