Antimicrobial Potential of Chitosan Films Incorporated with Alcoholic Extract from Mimosa tenuiflora Leaves.

Antimicrobial films were prepared with chitosan containing the methanolic extract of M. tenuiflora leaves (FECT20%, FECT30%, and FECT40%), and their antimicrobial activities were evaluated by agar diffusion. The films were characterized by IR spectroscopy, scanning electron microscopy (SEM) and TG/DTG curves. TG/DTG curves showed thermal stability of chitosan-extract films up to 166 ºC. Micrographs of chitosan-extract films revealed an increase in porosity with the addition of extract. The FECT40% film showed inhibition zone diameters (IZ) against Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, and B. cereus, ranging from 1.0 ± 0.02 to 0.72 ± 0.09 cm. Only FECT30% and FECT40% inhibited the P. aeruginosa with IZs of 0.68 ± 0.02 and 0.77 ± 0.06 cm, respectively. In turn, the extract showed inhibition against B. subtilis and B. cereus, with IZs values of 0.92 ± 0.2 cm and 0.72 ± 0.05 cm, respectively. Additionally, the crude extract presented antioxidant potential with inhibition percentages of 32.74% ± 0.90 for ABTS and 27.04% ± 1.36 for DPPH. The antimicrobial and antioxidant activities of the crude extract, as well as the antimicrobial property of chitosan-extract films, suggests the potential of these biopolymers for the development of wound healing bandages and new food packaging alternatives.

Evaluation of 1,9-Dimethyl-Methylene Blue nanoencapsulation using rhamnolipid nanoparticles to potentiate the Photodynamic Therapy technique in Candida albicans: In vitro study.

With the rapid development of nanotechnology, various functional nanomaterials have shown exciting potential in biomedical areas such as drug delivery, antitumor, and antibacterial therapy. These nanomaterials improve the stability and selectivity of loaded drugs, reduce drug-induced side effects, realize controlled and targeted drug release, and increase therapeutic efficacy. The increased resistance to antifungal microbicides in medical practice and their side effects stimulate interest in new therapies, such as Photodynamic Therapy (PDT), which do not generate resistance in microorganisms and effectively control the pathology. The present study aimed to evaluate, in vitro, the efficacy of photodynamic therapy on Candida albicans using 1,9-Dimethyl-Methylene Blue (DMMB) as photosensitizer, red LED (λ630), and nanoencapsulation of DMMB (RL-NPs/DMMB) using rhamnolipids produced by Pseudomonas aeruginosa to evaluate if there is better performance of DMMB + RL particles compared to DMMB alone via the characterization of DMMB + RL and colony forming count. The tests were carried out across six experimental groups (Control, DMMB, RL-NPs, RL-NPs/DMMB, PDT and PDT + RL-NPs/DMMB) using in the groups with nanoparticles, DMMB (750 ng/mL) encapsulated with rhamnolipids in a 1:1 ratio, the light source consisted of a prototype built with a set of red LEDs with an energy density of 20 J/cm2. The results showed that applying PDT combined with encapsulation (RL-NPs/DMMB) was a more practical approach to inhibit Candida albicans (2 log reduction) than conventional applications, with a possible clinical application protocol.

Exploring Culture Media Diversity to Produce Fungal Secondary Metabolites and Cyborg Cells.

Fungi are microorganisms of significant biotechnological importance due to their ability to provide food and produce several value-added secondary metabolites and enzymes. Its products move billions of dollars in the pharmaceutical, cosmetics, and additives sectors. These microorganisms also play a notable role in bionanotechnology, leading to the production of hybrid biological-inorganic materials (such as cyborg cells) and the use of their enzyme complex in the biosynthesis of nanoparticles. In this sense, optimizing the fungal growth process is necessary, with selecting the cultivation medium as one of the essential factors for the microorganism to reach its maximum metabolic expression. The culture medium's composition can also impact the nanomaterial's stability and prevent the incorporation of nanoparticles into fungal cells. Therefore, our main objectives are the following: (1) compile and discuss the most commonly employed culture media for the production of fungal secondary metabolites and the formation of cyborg cells, accompanied by preparation methods; (2) provide a six-step guide to investigating the fungal metabolomic profile and (3) discuss the main procedures of microbial cultivation to produce fungal cyborg cells.

A Review about the Mycoremediation of Soil Impacted by War-like Activities: Challenges and Gaps.

(1) Background: The frequency and intensity of war-like activities (war, military training, and shooting ranges) worldwide cause soil pollution by metals, metalloids, explosives, radionuclides, and herbicides. Despite this environmentally worrying scenario, soil decontamination in former war zones almost always involves incineration. Nevertheless, this practice is expensive, and its efficiency is suitable only for organic pollutants. Therefore, treating soils polluted by wars requires efficient and economically viable alternatives. In this sense, this manuscript reviews the status and knowledge gaps of mycoremediation. (2) Methods: The literature review consisted of searches on ScienceDirect and Web of Science for articles (1980 to 2023) on the mycoremediation of soils containing pollutants derived from war-like activities. (3) Results: This review highlighted that mycoremediation has many successful applications for removing all pollutants of war-like activities. However, the mycoremediation of soils in former war zones and those impacted by military training and shooting ranges is still very incipient, with most applications emphasizing explosives. (4) Conclusion: The mycoremediation of soils from conflict zones is an entirely open field of research, and the main challenge is to optimize experimental conditions on a field scale.

Unveiling the Surface and the Ultrastructure of Palladized Fungal Biotemplates.

In this paper, two biosystems based on filamentous fungi and Pd nanoparticles (NPs) were synthesized and structurally characterized. In the first case, results concerning the integration and distribution of Pd-NPs on Phialomyces macrosporus revealed that nanoparticles are accumulated on the cell wall, keeping the cytoplasm isolated from abiotic particles. However, the Penicillium sp. species showed an unexpected internalization of Pd-NPs in the fungal cytosol, becoming a promising biosystem to further studies of in vivo catalytic reactions. Next, we report a new solution-based strategy to prepare palladized biohybrids through sequential reduction of Pd2+ ions over previously harvested fungus/Au-NP composites. The chemical composition and the morphology of the biohybrid surface were characterized using a combination of scanning electron microscopy, transmission electron microscopy, and photoelectron spectroscopy. The deposition of Pd0 over the fungal surface produced biohybrids with a combination of Au and Pd in the NPs. Interestingly, other chemical species such as Au+ and Pd2+ are also observed on the outermost wall of microorganisms. Finally, the application of A. niger/AuPd-NP biohybrids in the 3-methyl-2-buten-1-ol hydrogenation reaction is presented for the first time. Biohybrids with a high fraction of Pd0 are active for this catalytic reaction.

Aging effect on vanadium oxide hybrid nanotubes.

Vanadium oxides present a rich magnetic phase diagram depending on the oxidation state of the V ions. In particular the vanadium oxide nanotubes (VO x NTs) present several promising perspectives for different technological applications for which it is essential to know the oxidation state of V ions, as well as to evaluate the stability with the aging time of the tubes. In this work we present a systematic study of the time evolution of the magnetic properties of VO x NTs. For this complete characterization, we used electron spin resonance (ESR) and dc-susceptibility techniques, which were supplemented with TEM microscopy and XANES. We observed that for aging in normal environmental conditions of pressure, temperature and humidity, the V4+ ions oxidize to V5+ . Although the multiwall tubular structure is maintained, this oxidation process produces a marked change in the magnetic properties. We conclude that the aging of the samples affects the V4+ /V5+ relationship in the VO x NTs, which may contribute to explain the significant dispersion of data reported in the bibliography.

Photoluminescent organisms: how to make fungi glow through biointegration with lanthanide metal-organic frameworks.

We show that filamentous fungi can emit green or red light after the accumulation of particulate lanthanide metal-organic frameworks over the cell wall. These new biohybrids present photoluminescence properties that are unaffected by the components of the cell wall. In addition, the fungal cells internalise lanthanide metal-organic framework particles, storing them into organelles, thereby making these materials promising for applications in living imaging studies.

Bio-inspired gold microtubes based on the morphology of filamentous fungi.

This communication describes a general method for templating fungal filaments with gold nanoparticles that results in a gold replica of filaments after calcination of the biological template.