Virus adsorbent systems based on Amazon holocellulose and nanomaterials.

The environment preservation has been an important motivation to find alternative, functional, and biodegradable materials to replace polluting petrochemicals. The production of nonbiodegradable face masks increased the concentration of microplastics in the environment, highlighting the need for sustainable alternatives, such as the use of local by-products to create efficient and eco-friendly filtering materials. Furthermore, the use of smart materials can reduce the risk of contagion and virus transmission, especially in the face of possible mutations. The development of novel materials is necessary to ensure less risk of contagion and virus transmission, as well as to preserve the environment. Taking these factors into account, 16 systems were developed with different combinations of precursor materials (holocellulose, polyaniline [ES-PANI], graphene oxide [GO], silver nanoparticles [AgNPs], and activated carbon [AC]). Adsorption tests of the spike protein showed that the systems containing GO and AC were the most efficient in the adsorption process. Similarly, plate tests conducted using the VSV-IN strain cultured in HepG2 cells showed that the system containing all phases showed the greatest reduction in viral titer method. In agreement, the biocompatibility tests showed that the compounds extracted from the systems showed low cytotoxicity or no significant cytotoxic effect in human fibroblasts. As a result, the adsorption tests of the spike protein, viral titration, and biocompatibility tests showed that systems labeled as I and J were the most efficient. In this context, the present research has significantly contributed to the technological development of antiviral systems, with improved properties and increased adsorption efficiency, reducing the viral titer and contributing efficiently to public health. In this way, these alternative materials could be employed in sensors and devices for filtering and sanitization, thus assisting in mitigating the transmission of viruses and bacteria. RESEARCH HIGHLIGHTS: Sixteen virus adsorbent systems were developed with different combinations of precursor materials (holocellulose, polyaniline (ES-PANI), graphene oxide (GO), silver nanoparticles (AgNPs), and activated carbon (AC)). The system that included all of the nanocomposites holocellulose, PANI, GO, AgNPs, and AC showed the greatest reduction in viral titration. The biocompatibility tests revealed that all systems caused only mild or moderate cytotoxicity toward human fibroblasts.

Influence of temperature combined with photodynamic inactivation on the development of Aedes aegypti.

To reduce the speed of selection of populations resistant to chemical insecticides, photodynamic inactivation (PDI) against Aedes aegypti is a hot-topic and promising alternative technique to vector control. Temperature is an important factor in the survival of Ae. aegypti larvae and mosquitoes as it influences physiology, behavior, and ecology. This work aimed to evaluate parameters of the biological cycle of Ae. aegypti such as: hatching rate, larval development, adult mosquito longevity, sex ratio, weight, and lethal concentration of larval mortality (LC) through the combination of PDI with different temperatures. The number of larvae found after 48 h suggests that temperature affects hatching rate. Additionally, results showed a delay in development of surviving larvae after PDI when compared to control groups, and there was a reduction in the longevity of mosquitoes that undertook photodynamic action. PDI also led to a predominance of male insects, and observed weight indicates that the inactivation method may have also interfered in mosquito size. The results point to a satisfactory performance of PDI at all tested temperatures. Experimental conditions that were not lethal to all larvae implied that PDI impacts the mosquitoes' biological cycle. Though metabolism and development are improved at higher temperatures, so is PDI action, thus maintaining the net benefit. Therefore, it is assumed that the proposed photolarvicide can be useful in reducing arbovirus transmission, and results invite for future research in different abiotic conditions.

Ultrasonic scalpel associated with photodynamic therapy in the treatment of refractory vulvar condyloma acuminatum.

This is a case report of a patient with vulvar condyloma acuminatum associated with hyperkeratosis and folliculitis, which had been refractory to two previous therapies. The patient had been successfully treated using a combination of promising techniques: the ultrasonic scalpel and MAL photodynamic therapy.

Spectroscopic Identification of Bacteria Resistance to Antibiotics by Means of Absorption of Specific Biochemical Groups and Special Machine Learning Algorithm.

FTIR (Fourier transform infrared spectroscopy) is one analytical technique of the absorption of infrared radiation. FTIR can also be used as a tool to characterize profiles of biomolecules in bacterial cells, which can be useful in differentiating different bacteria. Considering that different bacterial species have different molecular compositions, it will then result in unique FTIR spectra for each species and even bacterial strains. Having this important tool, here, we have developed a methodology aimed at refining the analysis and classification of the FTIR absorption spectra obtained from samples of Staphylococcus aureus, with the implementation of machine learning algorithms. In the first stage, the system conforming to four specified species groups, Control, Amoxicillin induced (AMO), Gentamicin induced (GEN), and Erythromycin induced (ERY), was analyzed. Then, in the second stage, five hidden samples were identified and correctly classified as with/without resistance to induced antibiotics. The total analyses were performed in three windows, Carbohydrates, Fatty Acids, and Proteins, of five hundred spectra. The protocol for acquiring the spectral data from the antibiotic-resistant bacteria via FTIR spectroscopy developed by Soares et al. was implemented here due to demonstrating high accuracy and sensitivity. The present study focuses on the prediction of antibiotic-induced samples through the implementation of the hierarchical cluster analysis (HCA), principal component analysis (PCA) algorithm, and calculation of confusion matrices (CMs) applied to the FTIR absorption spectra data. The data analysis process developed here has the main objective of obtaining knowledge about the intrinsic behavior of S. aureus samples within the analysis regions of the FTIR absorption spectra. The results yielded values with 0.7 to 1 accuracy and high values of sensitivity and specificity for the species identification in the CM calculations. Such results provide important information on antibiotic resistance in samples of S. aureus bacteria for potential application in the detection of antibiotic resistance in clinical use.

Effects on Colonization Factors and Mechanisms Involved in Antimicrobial Sonophotodynamic Inactivation Mediated by Curcumin.

Photodynamic (PDI) and sonodynamic (SDI) inactivation have been successfully employed as antimicrobial treatments. Moreover, sonophotodynamic inactivation (SPDI), which is the simultaneous application of PDI and SDI, has demonstrated greater effects. This study assessed the effects of PDI (PDI group), SDI (SDI group) and SPDI (SPDI group) using curcumin as a sensitizer on the metabolism, adhesion capability, biofilm formation ability and structural effects in a Staphylococcus aureus biofilm. Moreover, the production of reactive oxygen species (ROS) and the degradation spectrum of curcumin under the irradiation sources were measured. SPDI was more effective in inactivating the biofilm than PDI and SDI. All treatments reduced the adhesion ability of the bacteria: 58 ± 2%, 58 ± 1% and 71 ± 1% of the bacterial cells adhered to the polystyrene plate after the SPDI, SDI and PDI, respectively, when compared to 79 ± 1% of the untreated cells (control group). This result is probably related to the metabolism cell reduction after treatments. The metabolism of cells from the PDI group was 89 ± 1% lower than the untreated cells, while the metabolic activity of SDI and SPDI groups were 82 ± 2% and 90 ± 1% lower, respectively. Regarding the biofilm formation ability, all treatments (SPDI, SDI and PDI) reduced the total biomass. The total biomass of the PDI, SDI and SPDI groups were 26 ± 2%, 31 ± 5% and 35 ± 6% lower than the untreated biofilm (control group), respectively. Additionally, all treatments produced ROS and caused significant structural changes, reducing cells and the extracellular matrix. The light caused a greater absorbance decay of the curcumin; however, the US did not expressively alter its spectrum. Finally, SPDI had improved antimicrobial effects, and all treatments exhibited similar effects in the colonization factors evaluated.

Photon spectra effects tested on the vegetal model Allium cepa.

The use of artificial light sources in plants is considered a type of photobiomodulation (PBM), a trend in agriculture and food industries, aiming at decontamination, pest control, and increased production yield. However, literature lacks a broader assessment to address the effects of photon light spectra on plant characteristics. Here, we aimed to describe the effects of visible light, infrared, and ultraviolet light upon Allium cepa, a known bioindicator, under various light doses. Samples irradiated under visible and infrared light did not show cytotoxicity, genotoxicity, or mutagenicity in any of the evaluated doses. Light induction at 460 and 635 nm significantly stimulated root development of the test organism. In contrast, 254 nm irradiation proved to be cytotoxic, genotoxic, and mutagenic. This work reveals and quantifies the spectral response of A. cepa seeds, suggesting that it can be proposed as a model for future research on mechanisms of PBM in plants.

Multifunctional bilayer membranes composed of poly(lactic acid), beta-chitin whiskers and silver nanoparticles for wound dressing applications.

Nanomaterial-based wound dressings have been extensively studied for the treatment of both minor and life-threatening tissue injuries. These wound dressings must possess several crucial characteristics, such as tissue compatibility, non-toxicity, appropriate biodegradability to facilitate wound healing, effective antibacterial activity to prevent infection, and adequate physical and mechanical strength to withstand repetitive dynamic forces that could potentially disrupt the healing process. Nevertheless, the development of nanostructured wound dressings that incorporate various functional micro- and nanomaterials in distinct architectures, each serving specific purposes, presents significant challenges. In this study, we successfully developed a novel multifunctional wound dressing based on poly(lactic acid) (PLA) fibrous membranes produced by solution-blow spinning (SBS) and electrospinning. The PLA-based membranes underwent surface modifications aimed at tailoring their properties for utilization as effective wound dressing platforms. Initially, beta-chitin whiskers were deposited onto the membrane surface through filtration, imparting hydrophilic character. Afterward, silver nanoparticles (AgNPs) were incorporated onto the beta-chitin layer using a spray deposition method, resulting in platforms with antimicrobial properties against both Staphylococcus aureus and Escherichia coli. Cytotoxicity studies demonstrated the biocompatibility of the membranes with the neonatal human dermal fibroblast (HDFn) cell line. Moreover, bilayer membranes exhibited a high surface area and porosity (> 80%), remarkable stability in aqueous media, and favorable mechanical properties, making them promising candidates for application as multifunctional wound dressings.

Photobleaching Kinetics and Effect of Solvent in the Photophysical Properties of Indocyanine Green for Photodynamic Therapy.

Indocyanine green is an attractive molecule for photodynamic therapy due to its near infrared absorption, resulting in a higher tissue penetration. However, its quantum yields of the triplet and singlet state have been reported to be low and then, reactive oxygen species are unlikely to be formed. Aiming to understand the ICG role in photodynamic response, its photobleaching behavior in solution has been studied under distinct conditions of CW laser irradiation at 780 and 808 nm, oxygen saturations and solvents. Sensitizer bleaching and photoproduct formation were measured by absorption spectroscopy and analyzed using the PDT bleaching macroscopic model to extract physical parameters. ICG photobleaching occurs even at lower oxygen concentrations, indicating that the molecule presents more than one way of degradation. Photoproducts were produced even in solution of less than 4 % oxygen saturation for both solvents and excitation wavelengths. Also, the amplitude of absorption related to J-dimers was increased during irradiation, but only in 50 % PBS solution. The formation of photoproducts was enhanced in the presence of J-type dimers under low oxygen concentration, and the quantum yields of triplet and singlet states were one order of magnitude and two times higher, respectively, when compared to ICG in distilled H2 O.

Fast Fabrication of Multifunctional PCL/Curcumin Nanofibrous Membranes for Wound Dressings.

Therapeutic intervention to skin wounds requires covering the affected area with wound dressings. Interdisciplinary efforts have focused on the development of smart bandages that can perform multiple functions. In this direction, here, we designed a low cost (U$0.012 per cm2) multifunctional therapeutic wound dressing fabricated by loading curcumin (CC) into poly(ϵ-caprolactone) (PCL) nanofibers using solution blow spinning (SBS). The freestanding PCL/CC bandages were characterized by distinct physicochemical approaches and were successful in performing varied functions, including controlled release of CC, colorimetric indication of the wound conditions, barrier against microorganisms, being biocompatible, and providing a photosensitive platform for antimicrobial photodynamic therapy (aPDT). The chemical nature of PCL and CC and the interactions between these components allowed CC to be released for 192 h (ca. 8 days), which could be correlated with the Korsmeyer-Peppas model, with a burst release suitable to treat the inflammatory phase. Due to the CC keto-enol tautomerism, an optical indication of the healing status could be obtained using PCL/CC, which occurred immediately, ranging between red/orange and yellow shades. The effect against pathogenic microorganisms evaluated by agar disc-diffusion, affected skin wound simulation (ex vivo), and microbial penetration tests demonstrated the ability to block and inhibit microbial permeation in different environments. The biocompatibilities of PCL and PCL/CC were verified by in vitro cytotoxicity study, which demonstrated that cell viabilities average above 94 and 96% for human dermal fibroblasts. In addition, the proposed bandage responded to aPDT applied to an in vivo assay, showing that, when irritated, PCL/CC was able to reduce the bacteria present on the real wound of mice. In summary, our findings demonstrate that using PCL and CC to produce nonwovens by the SBS technique offers potential for the rapid fabrication of biocompatible and multifunctional wound dressings, paving the way for large-scale production and utilization of such dressings in the treatment of skin wounds.

Structural basis of antibacterial photodynamic action of curcumin against S. aureus.

Antimicrobial photodynamic therapy (aPDT) is an alternative tool to commercial antibiotics for the inactivation of pathogenic bacteria (e.g., S. aureus). However, there is still a lack of understanding of the molecular modeling of the photosensitizers and their mechanism of action through oxidative pathways. Herein, a combined experimental and computational evaluation of curcumin as a photosensitizer against S. aureus was performed. The radical forms of keto-enol tautomers and the energies of curcumin's frontier molecular orbitals were evaluated by density functional theory (DFT) to point out the photodynamic action as well as the photobleaching process. Furthermore, the electronic transitions of curcumin keto-enol tautomers were undertaken to predict the transitions as a photosensitizer during the antibacterial photodynamic process. Moreover, molecular docking was used to evaluate the binding affinity with the S. aureus tyrosyl-tRNA synthetase as the proposed a target for curcumin. In this regard, the molecular orbital energies show that the curcumin enol form has a character of 4.5% more basic than the keto form - the enol form is a more promising electron donor than its tautomer. Curcumin is a strong electrophile, with the enol form being 4.6% more electrophilic than its keto form. In addition, the regions susceptible to nucleophilic attack and photobleaching were evaluated by the Fukui function. Regarding the docking analysis, the model suggested that four hydrogen bonds contribute to the binding energy of curcumin's interaction with the ligand binding site of S. aureus tyrosyl-tRNA synthetase. Finally, residues Tyr36, Asp40, and Asp177 contact curcumin and may contribute to orienting the curcumin in the active area. Moreover, curcumin presented a photoinactivation of 4.5 log unit corroborating the necessity of the combined action of curcumin, light, and O2 to promote the photooxidation damage of S. aureus. These computational and experimental data suggest insights regarding the mechanism of action of curcumin as a photosensitizer to inactivate S. aureus bacteria.

Carbon dots: Types, preparation, and their boosted antibacterial activity by photoactivation. Current status and future perspectives.

Carbon dots (CDs) correspond to carbon-based materials (CBM) with sizes usually below 10 nm. These nanomaterials exhibit attractive properties such us low toxicity, good stability, and high conductivity, which have promoted their thorough study over the past two decades. The current review describes four types of CDs: carbon quantum dots (CQDs), graphene quantum dots (GQDs), carbon nanodots (CNDs), and carbonized polymers dots (CPDs), together with the state of the art of the main routes for their preparation, either by "top-down" or "bottom-up" approaches. Moreover, among the various usages of CDs within biomedicine, we have focused on their application as a novel class of broad-spectrum antibacterial agents, concretely, owing their photoactivation capability that triggers an enhanced antibacterial property. Our work presents the recent advances in this field addressing CDs, their composites and hybrids, applied as photosensitizers (PS), and photothermal agents (PA) within antibacterial strategies such as photodynamic therapy (PDT), photothermal therapy (PTT), and synchronic PDT/PTT. Furthermore, we discuss the prospects for the possible future development of large-scale preparation of CDs, and the potential for these nanomaterials to be employed in applications to combat other pathogens harmful to human health. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Polyurethane films formation from microcrystalline cellulose as a polyol and cellulose nanocrystals as additive: Reactions favored by the low viscosity of the source of isocyanate groups used.

To simultaneously form films while synthesizing solvent-free and catalyst-free bio-based polyurethanes, hexamethylene diisocyanate trimer was selected as an isocyanate group source to produce a low-viscosity reaction medium for dispersing high contents of microcrystalline cellulose (MCC, polyol) and cellulose nanocrystals (CNC). Castor oil was used as an additional polyol source. Up to 80 % of the MCC was dispersed, producing a film exhibiting the highest Tg (72 °C), tensile strength (18 MPa), and Young's modulus (522.4 MPa). 12.5 % (30 % MCC) and 7.5 % (50 % MCC) of CNC dispersed in the reaction medium formed films stiffer than their counterparts. All the films exhibited transparency and high crystallinity. The contact angle/zeta potential (ζ) indicated hydrophobic film surfaces. At pH 7.4, ζ suggested that the films interacted with physiological fluids favorably. The films were non-cytotoxic, and the composites exhibited cell growth compared with the control. The reported results, as far as it is known, are unprecedented.

Natural versus synthetic curcuminoids as photosensitizers: Photobleaching and antimicrobial photodynamic therapy evaluation.

Antimicrobial photodynamic therapy (aPDT) has been studied as an alternative to combat bacterial resistance to the commonly used antibiotics. aPDT requires the use of a photosensitizer and curcumin is one of the more promising, though the usage of natural curcumin can be inconsistent in certain biomedical uses due to differences in soil condition and turmeric age, besides a large quantity of the plant is necessary to obtain useful amounts of the actual molecule. As such, a synthetic analogue is preferred as it is pure, and its components are better characterized. The present work studied photophysical differences in both natural and synthetic curcumin using photobleaching experiments and searched for whether differences existed in aPDT studies against Staphylococcus aureus. The results showed a faster O2 consumption and a singlet oxygen's generation rate lower by the synthetic curcumin, in comparison with the natural derivative. However, no statistical difference was observed when inactivating S. aureus and these results were following a concentration-based pattern. Thus, the use of synthetic curcumin is indicated, as it can be obtained in controlled amounts and with less environmental impact. Although there are small changes in a photophysical context comparing natural versus synthetic curcumins, we did not observe statistical differences in the photoinactivation of S.aureus bacteria, and reproducibility in biomedical contexts is better achieved with the synthetic analogue.

ERRATUM: Kidney decontamination during perfusion for transplantation procedure: In vitro and ex vivo viability analysis.

Organ transplantations have an increasing medical relevance. It is becoming a regular procedure with an increase in individuals waiting for organs. The increase in the number of discarded organs is mostly due to the donor's bacterial and/or viral infection. In this article, we are demonstrating the feasibility of reduction of the bacterial load in the kidney model by using Ultraviolet-C (UV-C) as a germicidal agent in circulating liquids. Using Staphylococcus aureus as a bacteria model, we were able to demonstrate that in less than 30 min of liquid circulation and associated to irradiation, the bacterial load of the perfusate Custodiol® HTK, histidine-tryptophan-ketoglutarate (solution with 5 log CFU ml-1 ), was fully eliminated. A modeling approach was created to verify the possibility of bacterial load decrease, when an organ (here, a renal experimental model) is present in the circuit, releasing a varied rate of microorganisms over time, while the solution is irradiated. Finally, we use an ex vivo model with a swine kidney, circulating in the preservation solution with a Lifeport® Kidney Transporter machine, to demonstrate that we can contaminate the organ and then promote the elimination of the microbiological load. The results show the feasibility of the technique.

Biodefensive Based on Piper nigrum Essential Oil for Controlling of Anopheles aquasalis Larvae: Influence of Temperature (35 °C) and Preservatives.

Considerable efforts have been spent on the development of biodefensives based on the encapsulation of essential oils for controlling of urban pests from their larval stage, especially as anopheline controlling agents. The larval source management of Anopheles aquasalis is important for malaria prevention. For this reason, this research proposes larvicidal biodefensives based on polymeric particles loaded with Piper nigrum essential oil, considering the influence of temperature (35 °C) and preservatives on the formulation stability. The biodefensive containing the preservative phenoxyethanol/methylisothiazolinone (PNE) resulted in 5 months of shelf-life storage with an Encapsulation Efficiency (EE%) of essential oil of 70%. The biodefensive PNE (containing 500 µg.mL-1 of encapsulated essential oil) presented a polydisperse particle size distribution, ranging from D10 = (127 ± 10) nm to D90 = (472 ± 78) nm and a particle mean size of (236 ± 34) nm. The AFM images revealed a spherical morphology with an external surface almost regular and smooth. The controlled release of the essential oil was evaluated up to 72 h according to the Korsmeyer-Peppas mathematical model, confirming the anomalous transport (n = 0.64 in pH = 3 and pH = 10, and n = 0.65 in pH = 7). The total larvae mortality on the in loco bioassays was almost reached (92%) after 24 h. However, according to the in vitro bioassays applying the in natura essential oil alone, the concentration of 454 µg.mL-1 resulted on the mortality of 70% of the larvae after 24 h. For this reason, the highest efficiency of the biodefensive PNE may be related to the encapsulation of essential oil, delivering the loaded particles more efficiently inside the larvae. From this perspective, the present study shows that a formulation based on P. nigrum essential oil may be taken into account in the integrated management of disease vector mosquitoes.

Perfil de IL-6 e TNF na Formação de Células Espumosas: Um Método Aprimorado Usando a Sonda de Isotiocianato de Fluoresceína (FITC) / Profile of IL-6 and TNF in Foam Cell Formation: An Improved Method Using Fluorescein Isothiocyanate (FITC) Probe

Resumo Fundamento A formação de células espumosas ocorre devido ao aumento em lipoproteína plasmática de baixa densidade (LDL) e desregulação da inflamação, sendo importante para o desenvolvimento da aterosclerose. Objetivo Avaliar o perfil do fator de necrose tumoral alfa (TNF-α) e da interleucina-6 (IL-6) no método de formação da célula espumosa existente, otimizando esse protocolo. Métodos A LDL foi isolada, oxidada e marcada com sonda de isotiocianato de fluoresceína (FITC). As células espumosas foram geradas de célula derivada de monócitos humanos THP-1 e incubadas na ausência (controle) ou presença de FITC-ox-LDL (10, 50, 100, 150 ou 200 μg/mL), por 12, 24, 48 ou 72 horas. A FITC-ox-LDL na célula foi quantificada por microscopia. O ensaio de imunoabsorção enzimática foi avaliado para quantificar a IL-6 e o TNF-α, com um p <0,05 considerado significativo. Resultados Todas as concentrações de FITC-ox-LDL testadas apresentaram fluorescência mais alta em comparação com o controle, demonstrando maior acúmulo de lipoproteínas nas células. Quanto mais alta a concentração de FITC-ox-LDL, maior a produção de TNF-α e IL-6. A produção de IL-6 pelas células espumosas foi detectada até o valor de 150 µg/mL da LDL máxima de estímulo. Concentrações acima de 50 μg/mL de LDL estimularam maior liberação de TNF-α comparado ao controle. Conclusões Nosso modelo contribui para o entendimento da liberação de IL-6 e TNF-α em resposta a várias concentrações de ox-LDL usando o método otimizado para a formação de células espumosas.

Abstract Background The formation of foam cells occurs due to the increase in low-density plasma lipoprotein (LDL) and dysregulation of inflammation, which is important for the development of atherosclerosis. Objective To evaluate the profile of tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) in the existing foam cell formation method, optimizing this protocol. Methods The LDL was isolated, oxidized, and labeled with a Fluorescein isothiocyanate (FITC) probe. Foam cells were generated from THP-1 human monocyte-derived cells and incubated in the absence (control) or presence of FITC-ox-LDL (10, 50, 100, 150, or 200 μg/mL), for 12, 24, 48, or 72 hours. The accumulated FITC-ox-LDL in the cell was quantified by microscopy. The enzyme-linked immunosorbent assay was evaluated to quantify the IL-6 and TNF-α, with p < 0.05 considered significant. Results All the FITC-ox-LDL concentrations tested showed a higher fluorescence when compared to the control, showing a greater accumulation of lipoprotein in cells. The higher the concentration of FITC-ox-LDL, the greater the production of TNF-α and IL-6. The production of IL-6 by foam cells was detected up to the value of 150 µg/mL of the maximum stimulus for LDL. Concentrations above 50 μg/mL LDL stimulated greater release of TNF-α compared to control. Conclusions Our model contributes to the understanding of the release of IL-6 and TNF-α in response to different concentrations of ox-LDL, using an optimized method for the formation of foam cells.

PLGA-PVA-PEG Single Emulsion Method as a Candidate for Aminolevulinic Acid (5-ALA) Encapsulation: Laboratory Scaling Up and Stability Evaluation.

One of the most widely used molecules used for photodynamic therapy (PDT) is 5-aminolevulinic acid (5-ALA), a precursor in the synthesis of tetrapyrroles such as chlorophyll and heme. The 5-ALA skin permeation is considerably reduced due to its hydrophilic characteristics, decreasing its local bioavailability and therapeutic effect. For this reason, five different systems containing polymeric particles of poly [D, L-lactic-co-glycolic acid (PLGA)] were developed to encapsulate 5-ALA based on single and double emulsions methodology. All systems were standardized (according to the volume of reagents and mass of pharmaceutical ingredients) and compared in terms of laboratory scaling up, particle formation and stability over time. UV-VIS spectroscopy revealed that particle absorption/adsorption of 5-ALA was dependent on the method of synthesis. Different size distribution was observed by DLS and NTA techniques, revealing that 5-ALA increased the particle size. The contact angle evaluation showed that the system hydrophobicity was dependent on the surfactant and the 5-ALA contribution. The FTIR results indicated that the type of emulsion influenced the particle formation, as well as allowing PEG functionalization and interaction with 5-ALA. According to the 1H-NMR results, the 5-ALA reduced the T1 values of polyvinyl alcohol (PVA) and PLGA in the double emulsion systems due to the decrease in molecular packing in the hydrophobic region. The results indicated that the system formed by single emulsion containing the combination PVA-PEG presented greater stability with less influence from 5-ALA. This system is a promising candidate to successfully encapsulate 5-ALA and achieve good performance and specificity for in vitro skin cancer treatment.

Environmentally Safe Photodynamic Control of Aedes aegypti Using Sunlight-Activated Synthetic Curcumin: Photodegradation, Aquatic Ecotoxicity, and Field Trial.

This study reports curcumin as an efficient photolarvicide against Aedes aegypti larvae under natural light illumination. Larval mortality and pupal formation were monitored daily for 21 days under simulated field conditions. In a sucrose-containing formulation, a lethal time 50 (LT50) of 3 days was found using curcumin at 4.6 mg L-1. This formulation promoted no larval toxicity in the absence of illumination, and sucrose alone did not induce larval phototoxicity. The photodegradation byproducts (intermediates) of curcumin were determined and the photodegradation mechanisms proposed. Intermediates with m/z 194, 278, and 370 were found and characterized using LC-MS. The ecotoxicity of the byproducts on non-target organisms (Daphnia, fish, and green algae) indicates that the intermediates do not exhibit any destructive potential for aquatic organisms. The results of photodegradation and ecotoxicity suggest that curcumin is environmentally safe for non-target organisms and, therefore, can be considered for population control of Ae. aegypti.

Pulsatile Controlled Release and Stability Evaluation of Polymeric Particles Containing Piper nigrum Essential Oil and Preservatives.

Considerable efforts have been spent on environmentally friendly particles for the encapsulation of essential oils. Polymeric particles were developed to encapsulate the essential oil from Piper nigrum based on gelatin and poly-ε-caprolactone (PCL) carriers. Gas Chromatography ((Flame Ionization Detection (GC/FID) and Mass Spectrometry (GC/MS)), Atomic Force Microscopy (AFM), Nanoparticle Tracking Analysis (NTA), Confocal Laser Scanning Microscopy (CLSM), Attenuated Total Reflectance-Fourier-transform Infrared Spectroscopy (ATR-FTIR), and Ultraviolet-Visible (UV-VIS) spectroscopy were used for the full colloidal system characterization. The essential oil was mainly composed of ß-caryophyllene (~35%). The stability of the encapsulated systems was evaluated by Encapsulation Efficiency (EE%), electrical conductivity, turbidity, pH, and organoleptic properties (color and odor) after adding different preservatives. The mixture of phenoxyethanol/isotialzoni-3-one (PNE system) resulted in enhanced stability of approximately 120 and 210 days under constant handling and shelf-life tests, respectively. The developed polymeric system presented a similar controlled release in acidic, neutral, or basic pH, and the release curves suggested a pulsatile release mechanism due to a complexation of essential oil in the PCL matrix. Our results showed that the developed system has potential as an alternative stable product and as a controlling agent, due to the pronounced bioactivity of the encapsulated essential oil.

PANI-WO3·2H2O Nanocomposite: Phase Interaction and Evaluation of Electronic Properties by Combined Experimental Techniques and Ab-Initio Calculation.

The development of conjugated polymer-based nanocomposites by adding metallic particles into the polymerization medium allows the proposition of novel materials presenting improved electrical and optical properties. Polyaniline Emeraldine-salt form (ES-PANI) has been extensively studied due to its controllable electrical conductivity and oxidation states. On the other hand, tungsten oxide (WO3) and its di-hydrated phases, such as WO3·2H2O, have been reported as important materials in photocatalysis and sensors. Herein, the WO3·2H2O phase was directly obtained during the in-situ polymerization of aniline hydrochloride from metallic tungsten (W), allowing the formation of hybrid nanocomposites based on its full oxidation into WO3·2H2O. The developed ES-PANI-WO3·2H2O nanocomposites were successfully characterized using experimental techniques combined with Density Functional Theory (DFT). The formation of WO3·2H2O was clearly verified after two hours of synthesis (PW2 nanocomposite), allowing the confirmation of purely physical interaction between matrix and reinforcement. As a result, increased electrical conductivity was verified in the PW2 nanocomposite: the DFT calculations revealed a charge transfer from the p-orbitals of the polymeric phase to the d-orbitals of the oxide phase, resulting in higher conductivity when compared to the pure ES-PANI.