FTIR Analysis Research Articles

Stimuli-responsive gelatin-coated alginate nanocarriers: Targeted delivery of efflux pump inhibitor and antibacterial agents to control multidrug resistant P. aeruginosa

Multidrug resistance is an inescapable obstacle in healthcare settings. As the over-expression of efflux pumps is an important mediator of bacterial drug resistance, stimuli-responsive co-delivery nanosystems were developed for the sequential release of efflux pump inhibitors (EPI) and antibacterial agents. Gelatin-coated alginate nanocarriers (AlNCs@Gel) were developed containing ciprofloxacin (Cip) and quercetin (Que) as antibacterial/antibiofilm agents and EPI, respectively. Heat plot maps revealed a synergistic interaction of Cip with Que as the minimum inhibitory concentration value of Cip was reduced in the presence of EPI (quercetin) against P. aeruginosa. The encapsulation efficiency of 82 ± 1 % was observed for Cip while it was 70 ± 1 % for Que in Cip/AlNCs@Que/Gel nanocarriers. FTIR analyses confirmed an interaction between alginate and gelatin by the occurrence of a blue shift that is associated with electrostatic interactions between alginate and gelatin. These nanocarriers loaded with quercetin as EPI would release it preferentially in the presence of gelatinase enzyme and subsequently prevent the efflux of ciprofloxacin from bacterial cells. Membrane-permeability assay confirmed no permeabilization while viability studies exhibited superior bacterial inhibition, as Cip/EPI combination encapsulated in AlNCs@Gel effectively controlled the growth of P. aeruginosa as compared to antibiotic alone in AlNCs@Gel and free drug combinations. In vitro, cytotoxicity-analysis confirmed the biocompatibility of the developed core-shell nanocarriers. Furthermore, gelatin coating improved the physico-chemical properties of nanocarriers and the on-demand-release of EPI and antibiotic molecules. Thus, smartly designed AlNCs@Gel nanocarriers for the co-delivery of EPI and antibiotics present an innovative solution for preventing drug efflux from P. aeruginosa to control resistant infections.

Mechanochemical Polyoxometalate Super-Reduction with Lithium Metal.

In this first systematic investigation of mechanochemical polyoxometalate (POM) reduction, (TBA)3[PMo12O40] was reacted with n equiv of lithium metal (n = 1-24) to generate PMo12/n products which were shown to be mixtures of electron-rich PMo12Lix species. FTIR analysis revealed the lengthening/weakening of terminal Mo═O bonds with increasing levels of reduction, while EXAFS spectra indicated the onset of Mo-Mo bond formation at n ∼ 8 and a significant structural change at n > 12. Successive MoVI reductions were monitored by XANES and XPS, and at n = 24, results were consistent with the formation of at least one MoIV-MoIV bonded {MoIV3} triad together with MoV. Upon dissolution, the PMo12Lix species present in the solid PMo12/n products undergo electron exchange and single-peak 31P NMR spectra were observed for n = 1-12. For n ≥ 16, changes in solid state and solution 31P NMR spectra coincided with the emergence of features in the UV-vis spectra associated with MoV-MoV and {MoIV3} bonding in an ε-Keggin structure. Bonding between {Li(NCMe)}+ and 2-electron-reduced PMo12 in (TBA)4[PMo12O40{Li(NCMe)}] suggests that super-reduction gives rise to more extensive Li-O bonding that ultimately causes lithium-oxide-promoted TBA cation decomposition and POM degradation, which might explain the appearance of XPS peaks for Mo2C at n ≥ 16. This work has revealed some of the complex, unexplored chemistry of super-reduced POMs and establishes a new, solvent-free approach in the search for a better fundamental understanding of the electronic properties and reactivity of electron-rich nanoscale metal oxides.

Using gardenia pigment for ultrasonic natural dyeing of hemp fiber: A step towards sustainable dyeing

In recent years, with the country advocating the establishment of a resource-saving and environmentally friendly society, people have been pursuing a green and healthy quality of life. The non-toxic, harmless, and biodegradable characteristics of grass and wood dyeing have brought this method back to people's lives. Despite the presence of antibacterial substances such as tetrahydrocannabinol in cannabis fibers, they are still susceptible to microbial attacks. In recent years, scholars have conducted more research on the separation and purification of gardenia flower pigments, but there has been less analysis on the dyeing fibers and performance testing of gardenia flowers. The renewable characteristics, fewer side effects, and low cost increase the use of natural drugs as antibacterial agents in plant extracts or their active ingredients. This experiment used gardenia flowers as the raw material for dyeing experiments, and the dyeing percentage was used as the inspection index. Ultrasonic dyeing was carried out on hemp fibers after degumming treatment. It also aims to endow these dyed fabrics with natural antibacterial properties. During the sorting process, a liquid bath ratio of 1:20 was selected and experiments were conducted under different parameter variations. During the dyeing process, potassium aluminum sulfate (alum) is used as a mordant, and ultrasound is used as an auxiliary dyeing method. After dyeing, evaluate the fibers based on the percentage of exhaustion of obtained fiber and antibacterial activity against Staphylococcus aureus and Escherichia coli. At the same time, the FT-IR analysis, strength, and color fastness of the sorted samples were also checked. Single factor experiments were conducted by controlling the ultrasonic frequency, dyeing temperature, time, and mordant concentration to analyze the effect of gardenia pigment on the dyeing percentage. Response surface design experiments were used to optimize the dyeing process parameters. The research results indicate that the optimal process conditions for dyeing gardenia flowers are ultrasonic power of 85 %, dyeing temperature of 77 ℃, dyeing time of 60 min, and mordant concentration of 15 g/L. The main and secondary order of factors affecting the dyeing effect of hemp fibers is: mordant concentration>ultrasonic power>dyeing temperature. After optimal dyeing process, the hemp fiber shows a bright yellow color with a dyeing percentage of 57.32 %. The single fiber strength is not affected, and the color fastness to water washing and sun exposure meets the requirements for consumption. The infrared spectrum shows good dyeing effect. It has a certain antibacterial effect on Staphylococcus aureus, but the antibacterial effect on Escherichia coli is not significant. Due to these processes, it has been determined that hemp fiber can obtain antibacterial activity through the use of gardenia flowers and can be effectively colored.

Analysis on optical, thermal and third-order nonlinear properties of L-histidine hydrochloride monohydrate single crystal

This research contributes valuable insights into the understanding of third-order nonlinear optical effects in L-histidine hydrochloride monohydrate (LHHC) single crystal, offering a foundation for future work in optimizing its properties for practical applications in the field of nonlinear optics. It presents a systematic analysis into the LHHC crystal properties harvested by slow evaporation solution (SEST) method. Originally, structure of the compound was confirmed through single crystal x-ray diffraction and powder x-ray diffraction analysis. FTIR analysis was performed to get information about molecular composition of the compound. The assessment of the optical quality of LHHC single crystal was done by UV–Visible and photoluminescence spectroscopies. TG-DTA was employed to assess the stability of the single crystal under different temperature conditions. Z-scan technique, with an open aperture (OA) & closed aperture (CA) configuration, was employed to comprehensively explore the third-order nonlinear response of LHHC single crystal. The nonlinear absorption coefficient β is determined to be 5.32 × 10−10 cm W−1. The NLR index (n2) is calculated as −2.72 × 10−15 cm2 W−1.

Microplasma-assisted synthesis of chromium oxide nanoparticles and their biological activities

Chromium oxide nanoparticles are of significant interest and are widely used in numerous applications due to their exclusive physicochemical properties, including wide bandgap, increased stability, high melting temperature, and antibacterial and antifungal properties. In this study, the atmospheric pressure microplasma technique is used to synthesize chromium oxide nanoparticles by changing the precursor concentration (10, 15, and 20 mM). The nanoparticles are characterized by numerous techniques, including XRD, SEM, FTIR, UV-visible spectroscopy, RAMAN Spectroscopy, and antibacterial and antifungal activities. It is observed in XRD analysis that different phases of chromium oxide nanoparticles, Cr2O3 and CrO2, can be attained when the precursor concentration is changed. As a result, their efficiency can be tuned to different applications. The UV visible results depict that the band gap is reduced by increasing the precursor concentration (Cr(NO3)3.9H2O). The FTIR analysis is used to determine the surface functional groups of synthesized nanomaterials. Our results demonstrate the potential of chromium oxide nanoparticles as effective antibacterial and antifungal agents. Specifically, we found that these nanoparticles exhibit a strong antibacterial impact on gram-negative bacteria and a reasonable effect on gram-positive bacteria under some synthesis conditions. Moreover, they depict significant anti-fungal activity against two pathogenic fungus species, Penicillin Digitatum, and Rhizopus stolonifers. These promising findings, particularly for nanoparticles prepared at the concentration of 10 mM precursor with the Cr2O3 phase, reveal that these nanoparticles can be used efficiently for antibacterial (particularly gram-negative bacteria) and antifungal activities.

Chitosan Based Zinc and Copper Nanoparticles: Synthesis, Characterization and Antibacterial Activity Investigation

Chitosan biopolymer has been used as a key supporting material for the synthesis of metallic nanoparticles (MNPs) due to its exceptional qualities, which include good capping and stabilizing capabilities, biocompatibility, biodegradability, eco-friendliness, polycationic and non-toxicity. In this study, chitosan-based metal nanoparticles, such as copper nanoparticles (Chi-Cu NPs) and zinc nanoparticles (Chi-Zn NPs) have been synthesized, characterized and checked for their bacteriological properties. The solution casting method has been employed to produce metal nanoparticles based on chitosan. FTIR, TGA, and SEM analysis were employed to characterize the produced nanoparticles. The produced materials are nanomaterials with a size range of 1-100 nm, as demonstrated by the SEM photograph. The generated nanoparticles showed increased antimicrobial activity. Chi-Zn NPs have zones of inhibition of 38, 31, 30 and 39 and Chi-Cu NPs have zones of inhibition of 32, 36, 37 and 32 mm against Pseudomonas aeruginosa, Salmonella bovismorbificans, Salmonella typhi and Escherichia coli bacteria, respectively. Whereas the standard medication kanamycin have zones of inhibition 22, 22, 20 and 20 against those bacteria, respectively. Journal of Engineering Science 15(1), 2024, 45-57

Ortho to para hydrogen conversion over bimetallic iron and cobalt catalysts

The catalytic conversion of ortho-hydrogen (o-H2) to para-hydrogen (p-H2) serves as a crucial step in the storage of liquid hydrogen. A variety of iron-cobalt bimetallic catalysts (FCO) were synthesized using a precipitation method, incorporating diverse levels of Co doping into Fe-based catalysts. The effects of Co doping on the crystal structure, porosity, and magnetism of FCO catalysts were studied by XRD, N2 physical adsorption, FTIR, XPS, and VSM analyses. The efficiency of ortho-para hydrogen conversion over FCO at 77 K was evaluated. It was found that the catalyst’s lag coefficient was significantly improved by Co doping, leading to an increase of magnetic moment. The catalyst of FCO-5 with a Fe/(Fe + Co) molar ratio of 0.5 exhibited the highest activity in ortho-para hydrogen conversion. The corresponding conversion rate, outlet p-H2 content, and the reaction rate constant were 99.2%, 49.7% and 291.7 mol·L−1·s−1, respectively, under a gas hourly space velocity of 5400 h−1.

Electro-, photo-, and photoelectrochemical degradation of chloramphenicol on self-doping Ti nanotubes.

In this work, the photo-, electro-, and photo-electro-oxidation of chloramphenicol was investigated. The photo-experiments were carried out with different irradiation sources (an ultraviolet and a simulated solar source) using self-doped titanium nanotubes (SDTNT), a very promising and innovative material that deserves further investigations in the degradation of different pollutants. The photo-electrooxidation (j = 15mAcm-2) under simulated solar irradiation presented the best efficiency, with ca. 100% degradation and kinetic constant of k = 0.04427min-1. The FTIR analysis demonstrated a structural modification of the standard molecule occurred for all conditions used, suggesting a modification in functional groups responsible for the biological activity. Furthermore, the TOC analysis showed a significant mineralization of the pollutant (66% from the initial concentration). In addition, both photo-electrooxidation approaches have demonstrated a positive value of S, where the simulated solar irradiation reached the highest value S = 0.6960. The experimental results pointed out evidence that the methodology employed herein for chloramphenicol degradation is greatly interesting and the photo-electrooxidation under simulated solar irradiation is a promising approach for this purpose.

Plastic Debris in the Aquatic Environment: An Emerging Substratum for Antimicrobial Resistant (AMR) Biofilms.

Plastic pollution has quadrupled over the past years and has become a global concern due to its direct impact on life forms. The present study analysed whether the plastic debris in aquatic environments could act as the substratum for the antimicrobial-resistant (AMR) bacteria to form biofilm for survival. We have collected various plastic debris (n = 32) from six sites of the Periyar River, the drinking water source for the entire city and one of the most polluted rivers in Kerala (India). The chemical composition of plastics was screened via FTIR analysis and found that they comprised two types, viz., polyethylene and polypropylene. Bacteria isolated from the samples were screened for the AMR characteristics towards eight different classes of antibiotics. All isolates showed 100% resistance towards colistin and obtained the MAR index value of 0.1-0.4 range. Six representative bacterial isolates with high multiple antibiotic resistance (MAR) index were selected and identified by 16sRNA sequencing as Lysinibacillus mangiferihumi, Bacillus pumilus, Bacillus safensis, Bacillus cereus, Bacillus altitudins and Bacillus pumilus. In vitro biofilm formation was experimented on the purchased plastic samples in artificial media and river water using two selected strains, Bacillus pumilus and Bacillus cereus. Significant variations were observed in biofilm growth in different media (P < 0.05) regardless of plastic types (P > 0.05). The extracellular polymeric substances (EPS) and the characteristic holes on the surface morphology were visualized in SEM analysis, thus indicating the conditioning of the plastics by the isolates for biofilm formation.

Novel composite of nano zinc oxide and nano propolis as antibiotic for antibiotic-resistant bacteria: a promising approach

This study proposes an innovative approach to combat the escalating threat of antibiotic resistance in bacteria by introducing a novel ZnO-propolis nanocomposite (ZnO-P NCs). The overuse of antibiotics, particularly during events like the COVID-19 pandemic, has intensified bacterial resistance, necessitating innovative solutions. The study employs a cost-effective and controllable biosynthesis method to produce ZnO nanoparticles (ZnO-NPs), with propolis extract crucially contributing to the reduction and stabilization of Zn2+ ions. A biodegradable nano-propolis matrix is then created by incorporating ZnO-NPs, forming the ZnO-P NCs. Structural stability is confirmed through FT-IR and Zeta potential analysis, while nanoscale properties are validated via TEM, SEM, and XRD analyses. The antimicrobial efficacy of various substances, including propolis, nano propolis, ethanolic propolis extract, ZnO-NPs, and ZnO-P NCs, is assessed against Gram-negative and Gram-positive bacteria, alongside a comparison with 28 antibiotics. Among the bacteria tested, Pseudomonas aeruginosa PAO1 ATCC15692 was more sensitive (40 mm) to the biosynthesized nanocomposite ZnO-P NCs than to ZnO-NPs (38 mm) and nanopropolis (32 mm), while Escherichia coli was resistant to nanopropolis (0 mm) than to ZnO-NPs (31 mm), and ZnO-P NCs (34 mm). The study reveals a synergy effect when combining propolis with green-synthesized ZnO-NPs in the form of ZnO-P NCs, significantly improving their efficiency against all tested bacteria, including antibiotic-resistant strains like E. coli. The nanocomposite outperforms other materials and antibiotics, demonstrating remarkable antibacterial effectiveness. SEM imaging confirms the disruption of bacterial cell membranes by ZnO-NPs and ZnO-P NCs. The study emphasizes the potential applications of ZnO-NPs integrated into biodegradable materials and underscores the significance of the zinc oxide-propolis nanocomposite in countering antimicrobial resistance. Overall, this research offers a comprehensive solution to combat multidrug-resistant bacteria, opening avenues for novel approaches in infection control.

Boron removal from wastewater via coordinative adsorption assisted by Fenton-Induced Oxoprecipitation/Flocculation

Chemical precipitation is widely used for boron removal from water in industrial-scale processes, though a following post treatment is generally required to meet the concentration set by current international standards.In this work, chemical precipitation of boron (B) in water by different precipitating agents was combined with Fenton treatment to enhance the boron removal effectiveness. This approach achieved residual boron concentration of less than 0.5 mg/L, hard to achieve through conventional precipitation methods.Batch tests were performed at different dosage of Fenton reagents, and selected Fe2+/H2O2 weight ratios were evaluated with or without adding precipitating agents. The effect of pH on the process was also investigated, to assess the optimal conditions to maximize boron removal. At the end of the process, barium hydroxide was used to remove effectively excess sulfate ions.The sludge produced was characterized by XRD, SEM and FTIR analysis, and the mechanism of boron removal was investigated.An oxoprecipitation mechanism was induced by the Fenton process: boron-based species were converted into borate ion, thus predisposing them to a coordination-type adsorption on the surface of iron and calcium hydroxide, assisted by aluminum sulfate at pH 12.5.The process was then successfully tested on real boron −contaminated wastewater, thus confirming the effectiveness of the process while simultaneously decreasing the organic content.

Nano-Hydroxyapatite Modified Tobacco Stalk-Based Biochar for Immobilizing Cd(II): Interfacial Adsorption Behavior and Mechanisms

Biochar, an eco-friendly, porous carbon-rich material, is widely studied for immobilizing heavy metals in contaminated environments. This study prepared tobacco stalks, a typical agricultural waste, into biochar (TSB) modified by hydroxyapatite (HAP) at co-pyrolysis temperatures of 350 °C and 550 °C to explore its Cd(II) adsorption behavior and relevant mechanisms. XRD, SEM–EDS, FTIR, and BET analyses revealed that HAP successfully incorporated onto TSB, enriching the surface oxygen-containing functional groups (P–O and carboxyl), and contributing to the enhancement of the specific surface area from 2.52 (TSB350) and 3.63 m2/g (TSB550) to 14.07 (HAP–TSB350) and 18.36 m2/g (HAP–TSB550). The kinetics of Cd(II) adsorption onto TSB and HAP–TSB is well described by the pseudo-second-order model. Isotherm results revealed that the maximum adsorption capacities of Cd(II) on HAP–TSB350 and HAP–TSB550 were approximately 13.17 and 14.50 mg/g, 2.67 and 9.24 times those of TSB350 and TSB550, respectively. The Cd(II) adsorption amounts on TSBs and HAP–TSBs increased significantly with increasing pH, especially in HAP–TSB550. Ionic strength effects and XPS analysis showed that Cd(II) adsorption onto HAP–TSBs occurred mainly via electrostatic interaction, cation exchange with Ca2+, complexation with P–O and –COOH, and surface precipitation. These findings will provide a modification strategy for the reutilization of tobacco agricultural waste in the remediation of heavy metal contaminated areas.

Clove mediated synthesis of Ag-ZnO doped fucoidan nanocomposites and their evaluation of antibacterial, antioxidant and cytotoxicity efficacy study

The Ag-ZnO/Fu nanocomposites were successfully synthesized in an environmentally friendly manner using an aqueous Clove buds extract from the Syzygium aromaticum plant. They were then examined for antibacterial activity against bacterium strains of Escherichia coli, Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Enterococcus faecalis. The UV–Visible spectrophotometry analysis confirmed the presence of zinc oxide (ZnO) nanoparticles at 334 nm, silver oxide (Ag) nanoparticles at 416 nm, and fucoidan at 589 nm in the synthesized nanocomposites. The FT-IR analysis confirmed the presence of five different functional linkages in the synthesized nanocomposites. The positions of diffraction peaks in pure Ag-ZnO/Fu nanocomposite patterns were identified using XRD analysis. The Ag-ZnO/Fu nanocomposites synthesized are more crystalline (77 %), and less amorphous (22.2 %). Silver, O, and Zn signals were detected in the SEM and EDX spectra of the Ag-ZnO/Fu nanocomposite. Different strains of Ag-ZnO/Fu nanocomposites showed stronger antibacterial properties. The DPPH technique was used to perform the antioxidant assay. Cytotoxicity testing was carried out on zebrafish embryos treated with several groups of Clove Ag ZnO/Fucoidan. The combination Ag-ZnO/Fucoidan (300 mg/mL) showed a marginally significant difference in survival (94 %).

Thermal Behaviour, Chemical Composition and Morphological analysis of Cotton Stalk for Designing an Efficient Continuous Biochar Reactor.

The escalating concern over air pollution from crop stubble burning necessitates responsible biomass disposal. In our study, the characterisation studies of cotton stalk were done to assess the feasibility of this agriculture waste to be utilized for biochar production and design the continuous biochar unit. The experiment done at the Department of Unconventional Energy Sources and Electrical Engineering, College of Agricultural Engineering and Technology, Dr. PDKV, Akola during years 2021-2023. Proximate analysis revealed a varying bulk density (147.2 - 215.8 kg/m3) and moisture content (7.56-10.1%), while ultimate analysis unveiled diverse compositions, including cellulose (20-38%), hemicellulose (11-26%), and lignin (16-29%). The thermogravimetric analysis was done to study the degradation temperature of the cotton stalk with different heating rate viz. 10, 20, 30 and 40 ℃/min. The X-ray diffraction spectroscopy and Fourier transformation infrared spectroscopy was done for the cotton stalk to analyse the crystallinity and the biochemical composition of the cotton stalk. The results show that the good quality biochar can be prepared by using the low to medium temperature pyrolysis technique from the cotton stalk. The maximum degradation temperature for the cotton stalk was found to be around 450℃. The XRD and FT-IR analysis confirms the presence of the hemicellulose, cellulose and lignin in the cotton stalk which are the main precursor of the biochar production.

Cassava starch‐based film infused with biogenic selenium nanoparticles (bio‐SeNPs) to reduce foodborne pathogens

SummaryThe urgent investigation of antimicrobial films is imperative to mitigate the proliferation of pathogens in food, extending product shelf life and ensuring food safety, crucial aspects for public health and the sustainability of the global food system. We developed cassava starch‐based films containing 1% and 2% biogenic selenium nanoparticles (Bio‐SeNPs) produced by enterocin MF5 to assess antimicrobial activity. The addition of Bio‐SeNPs altered the luminosity and gave a reddish hue to the films. UV–visible, FTIR, and thermogram analyses revealed intermolecular interactions between the starch and Bio‐SeNPs. Scanning electron microscopy showed a smooth and homogeneous surface of the nanocomposite films. Water vapour permeability ranged from 9.4 to 0.68 g mm h−1 m−2 kPa−1, lower than control values. Swelling values were higher in the film containing 1% Bio‐SeNPs, and water vapour transmission was lower. The films exhibited MICs of 5.5 μL mL−1 for Listeria spp., 10.9 μL mL−1 for Salmonella spp., and 250 μL mL−1 for Escherichia coli. Antimicrobial activity ranged from 1.5–1.9 log and 1.6–2.0 log in liquid medium and dry film, respectively, after 24 h. The films were also applied to cherry tomatoes without altering their characteristics compared to the positive control. Our study demonstrated the high potential of using Bio‐SeNPs in biodegradable films to prevent food contamination.

Experimental Study for the Sorption and Diffusion of Supercritical Carbon Dioxide into Polyetherimide.

Supercritical carbon dioxide (SCCO2) is a non-toxic and environmentally friendly fluid and has been used in polymerization reactions, processing, foaming, and plasticizing of polymers. Exploring the behavior and data of SCCO2 sorption and dissolution in polymers provides essential information for polymer applications. This study investigated the sorption and diffusion of SCCO2 into polyetherimide (PEI). The sorption and desorption processes of SCCO2 in PEI samples were measured in the temperature range from 40 to 60 °C, the pressure range from 20 to 40 MPa, and the sorption time from 0.25 to 52 h. This study used the ex situ gravimetric method under different operating conditions and applied the Fickian diffusion model to determine the mass diffusivity of SCCO2 during sorption and desorption processes into and out of PEI. The equilibrium mass gain fraction of SCCO2 into PEI was reported from 9.0 wt% (at 60 °C and 20 MPa) to 12.8 wt% (at 40 °C and 40 MPa). The sorption amount increased with the increasing SCCO2 pressure and decreased with the increasing SCCO2 temperature. This study showed the crossover phenomenon of equilibrium mass gain fraction isotherms with respect to SCCO2 density. Changes in the sorption mechanism in PEI were observed when the SCCO2 density was at approximately 840 kg/m3. This study qualitatively performed FTIR analysis during the SCCO2 desorption process. A CO2 antisymmetric stretching mode was observed near a wavenumber of 2340 cm-1. A comparison of loss modulus measurements of pure and SCCO2-treated PEI specimens showed the shifting of loss maxima. This result showed that the plasticization of PEI was achieved through the sorption process of SCCO2.

Preparation and Characterization of Biodegradable Plastic from Red Seaweed (Gracilaria sp.) from Coastal Areas in Bangladesh

AbstractBioplastics are biobased or biodegradable plastic synthesized from natural resources with similar features to conventional plastic and environmental sustainability. Seaweed species abundant in the coastal regions of Bangladesh are yet to be explored for developing biodegradable plastic to solve the plastic pollution problem. Semi‐refined kappa carrageenan was extracted from Gracilaria sp. with Pressurized Hot Water Extraction (PHWE) and blended with sorbitol and polyethylene glycol 1540 in this study, respectively. The presence of carrageenan and other functional groups was confirmed with FTIR analysis. The bioplastic films showed over 90 % biodegradability after 16 days of soil burial test and 98 % water solubility after immersion for 16 days. Maximum 20 MPa tensile strength and 44 % elongation were observed from the bioplastic films. The polyethylene glycol 1540 blended films showed better physical and mechanical properties. SEM analysis was conducted to evaluate the influence of tensile strength and elongation on the surface integrity of the bioplastic films. The findings indicate that Gracilaria sp. found in the coastal regions of Bangladesh, can be a potential candidate for developing bioplastics for food packaging and many other applications.

The Impact of a Non-Pathogenic Strain of Fusarium Oxysporum on Structural and Biochemical Properties of Flax Suspension Cultures.

Flax (Linum usitatissimum L.) is an important crop plant with pharmaceutical significance. It is described in pharmacopoeias (the United States Pharmacopeia and the European Pharmacopoeia), which confirms that it (especially the seeds) is a valuable medicinal product. Similar to flax seeds, which accumulate bioactive compounds, flax in vitro cultures are also a rich source of flavonoids, phenolics, lignans and neolignans. In the present study, flax suspension cultures after treatment of the non-pathogenic Fusarium oxysporum strain Fo47 were established and analyzed. The study examined the suitability of Fo47 as an elicitor in flax suspension cultures and provided interesting data on the impact of these endophytic fungi on plant metabolism and physiology. Two flax cultivars (Bukoz and Nike) and two compositions of media for flax callus liquid cultures were tested. Biochemical analysis revealed enhanced levels of secondary metabolites (total flavonoid and total phenolic content) and photosynthetically active pigments in the flax callus cultures after treatment with the non-pathogenic fungal strain F. oxysporum Fo47 when compared to control, untreated cultures. In cultures with the selected, optimized conditions, FTIR analysis was performed and revealed changes in the structural properties of cell wall polymers after elicitation of cultures with F. oxysporum Fo47. The plant cell wall polymers were more strongly bound, and the crystallinity index (Icr) of cellulose was higher than in control, untreated samples. However, lignin and pectin levels were lower in the flax callus liquid cultures treated with the non-pathogenic strain of Fusarium when compared to the untreated control. The potential application of the non-pathogenic strain of F. oxysporum for enhancing the synthesis of desired secondary metabolites in plant tissue cultures is discussed.

Synergistic nanocoating with layer-by-layer functionalized PCL membranes enhanced by manuka honey and essential oils for advanced wound healing

Chronic wounds represent a significant global health concern, statistically impacting 1–2% of the population in developed countries throughout their lifetimes. These wounds cause considerable discomfort for patients and necessitate substantial expenditures of time and resources for treatment. Among the emerging therapeutic approaches, medicated dressings incorporating bioactive molecules, including natural compounds, are particularly promising. Hence, the objective of this study was to develop novel antimicrobial dressings for wound treatment. Specifically, polycaprolactone membranes were manufactured using the electrospinning technique and subsequently coated with natural polyelectrolytes (chitosan as a polycation and a mixture of manuka honey with essential oils nanoemulsions as a polyanion) employing the Layer-by-Layer assembly technique. Physico-chemical and morphological characterization was conducted through QCM-D, FTIR-ATR, XPS, and SEM analyses. The results from SEM and QCM-D demonstrated successful layer deposition and coating formation. Furthermore, FTIR-ATR and XPS analyses distinguished among different coating compositions. The coated membranes were tested in the presence of fibroblast cells, demonstrating biocompatibility and expression of genes coding for VEGF, COL1, and TGF-β1, which are associated with the healing process (assessed through RT-qPCR analysis). Finally, the membranes exhibited excellent antibacterial activity against both Staphylococcus aureus and Pseudomonas aeruginosa, with higher bacterial strain inhibition observed when cinnamon essential oil nanoemulsion was incorporated. Taken together, these results demonstrate the potential application of nanocoated membranes for biomedical applications, such as wound healing.

Green Silver Nanoparticles and Their Activity as Antifungal Agents Against Penicillium digitatum Causing Green Mould of Citrus

AbstractThe green synthesis of silver nanoparticles (SNPs) using aqueous extracts of five plants viz., Ocimum americanum, Azadirachta indica, Allium sativum, Eucalyptus hybrida, Zingiber officinale were evaluated for their antifungal property against Penicillium digitatum, a green mould pathogen of citrus fruits. The five plant species were selected from a screening of aqueous extracts from 16 plant species. The efficacy of aqueous extracts, at 50 % concentration, ranged from 14.44–68.52 % inhibition in mycelia growth of P. digitatum. Among SNPs, O. americanum was found most efficacious, at 1000 ppm concentration, with 80.7 % mycelial inhibition followed by A. indica with 77.4 % mycelial growth inhibition of fungal pathogen. Further, physical and structural characterization of SNPs of O. americanum and A. indica was carried out. The characterization analysis executed via transmission and scanning electron microscope revealed size distribution and nanoparticles were spherical to irregularly shaped ranging from 22.8–250 nm in O. americanum and 26.5–500 nm in A. indica. In UV‐visible spectrophotometer, the absolute absorption peak was recorded at 448 nm and 442 nm for O. americanum and A. indica, respectively. FTIR analysis of SNPs of A. indica and O. americanum confirmed the presence of carboxyl, amide group and secondary amines which were the main constituent of proteins. The novelty of the present study is in the green synthesis of silver nanoparticles with potential in the management of postharvest pathogens of fruit crops. The synthesis of SNPs used in this study is simple, environmentally benign and cost‐effective using aqueous extract of native plants.