RESUMO
Hydroxyapatite (HAp) is a calcium phosphate material that was used primarily in bone regeneration and repair as a result of its chemical similarity with bone. However, HAp has emerged as a very promising adsorbent for sequestering contaminants like heavy metals, dyes, hydrocarbons as well as other emerging pollutants from wastewater as a result of its versatility and encouraging adsorptive properties. Contaminants like heavy metals and dyes have been a major source of environmental concern. Research studies involving the use of HAp as adsorbents for the adsorptive treatment of heavy metal- and dye-contaminated wastewater have become increasingly popular due to its eco-friendliness, easy synthesis, unique adsorption properties etc. Various methods are available for the synthesis of HAp and its composites with some of these methods used in combination with other methods to obtain more efficient HAp-based adsorbents. In this work, the adsorptive removal of heavy metals and dyes by HAp and its composites was extensively reviewed as well as the parametric effects of process factors like contact time, solution pH, temperature, solute concentration etc on the adsorption process. Kinetic, thermodynamic, and isotherm models for elucidating the adsorption process were also considered. Generally, from the works reviewed, HAp-based adsorbents were found to be very effective for sequestering heavy metals and dyes from solution and thus presents a low-cost option for adsorptive wastewater treatment.
Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Corantes , Durapatita , Cinética , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
Anaerobic digestion of multiple substrates can generate more biogas while remaining stable, if positive synergistic effects are achieved. The type of co-digested substrates and the mixing ratio used, are the most important variables as each substrate has unique set of characteristics. Optimizing the volume ratios by testing various substrate mixing ratios is a popular method for determining the best-performing ratio of substrate mixture. The ternary mixture design has reportedly been found to quicken the process of testing different mixing ratios with high accuracy without running several experiments. Therefore, a ternary mixture design and a response surface approach are used in this work to ascertain the relationship between substrate mix and responses (biogas yield, methane yield, and synergy). The findings of the experiment revealed that R9 comprising 78.8 % human excreta, 11.8 % food leftovers and 9.4 % kitchen residue, had the highest methane production of 764.79 mLCH4/gVS and a synergistic index of 3.26. Additionally, the 3D response surface plots from the response surface model showed important and shared interactions between Human Excreta, (HE), Food Leftovers (FLO), and Kitchen Residue (KR). HE and KR had a similar positive synergistic effect on biogas yield, methane yield, and synergy, which was not the case for FLO. The response surface plots showed that the predicted responses (methane yield, biogas yield and synergy) increased with increasing HE and KR fractions and decreased with increasing FLO fractions in the substrate mixtures.
RESUMO
Given the escalating prevalence of drug-resistant wounds, there is a justified imperative to explore innovative and more efficacious therapies that diverge from conventional, ineffective wound healing approaches. This research has introduced a strategy to address multi-drug resistant (MDR) Pseudomonas aeruginosa infections in a chronic wound model, employing MDR-specific phage Pɸ-Mi-Pa loaded onto mucoadhesive electrospun scaffolds. A cocktail of three isolates of P. aeruginosa-specific lytic phages, Pɸ-Mi-Pa 51, Pɸ-Mi-Pa 120, and Pɸ-Mi-Pa 133 were incorporated into varying ratios of fabricated PCL-PVP polymer. These formulations were assessed for their therapeutic efficacy in achieving bacterial clearance in P. aeruginosa-induced wound infections. The study encompassed biological characterization through in vivo wound healing assessments, histology, and histomorphometry. Additionally, morphological, mechanical, and chemical analyses were conducted on the fabricated PCL-PVP electrospun nanofibrous scaffolds. Three clonal differences of the MDR P. aeruginosa-specific phages (Pɸ-Mi-Pa 51, Pɸ-Mi-Pa 120, and Pɸ-Mi-Pa 133) produced lytic activity and were seen to produce distinct and clear zones of inhibition against MDR P. aeruginosa strains Pa 051, Pa 120 and Pa 133 respectively. The average porosity of the nanofibrous scaffolds PB 1, PB 2, PB 3, and PB 4 were 12.2 ± 0.3 %, 22.1 ± 0.7 %, 31.1 ± 2.4 %, 28.0 ± 0.8 % respectively. In vitro cumulative release of MDR-specific phage Pɸ-Mi-Pa from the mucoadhesive electrospun nanofibrous scaffolds was found to be 70.91 % ± 1.02 % after 12 h of incubation after an initial release of 42.8 % ± 3.01 % after 1 h. Results from the in vivo wound healing study revealed a substantial reduction in wound size, with formulations PB 2 and PB 3 exhibiting the most significant reduction in wound size, demonstrating statistically significant results on day 5 (100 % ± 31.4 %). These findings underscore the potential of bacteriophage-loaded electrospun PCL-PVP nanofibrous scaffolds for treating drug-resistant wounds, generating tissue substitutes, and overcoming certain limitations associated with conventional wound care matrices.
RESUMO
Bacterial vaginosis (BV) is an infection of the vagina associated with thriving anaerobes, such as Gardnerella vaginitis and other associated pathogens. These pathogens form a biofilm responsible for the recurrence of infection after antibiotic therapy. The aim of this study was to develop a novel mucoadhesive polyvinyl alcohol and polycaprolactone electrospun nanofibrous scaffolds for vaginal delivery, incorporating metronidazole, a tenside, and Lactobacilli. This approach to drug delivery sought to combine an antibiotic for bacterial clearance, a tenside biofilm disruptor, and a lactic acid producer to restore healthy vaginal flora and prevent the recurrence of bacterial vaginosis. F7 and F8 had the least ductility at 29.25% and 28.39%, respectively, and this could be attributed to the clustering of particles that prevented the mobility of the crazes. F2 had the highest at 93.83% due to the addition of a surfactant that increased the affinity of the components. The scaffolds exhibited mucoadhesion between 31.54 ± 0.83% and 57.86 ± 0.95%, where an increased sodium cocoamphoacetate concentration led to increased mucoadhesion. F6 showed the highest mucoadhesion at 57.86 ± 0.95%, as compared to 42.67 ± 1.22% and 50.89 ± 1.01% for the F8 and F7 scaffolds, respectively. The release of metronidazole via a non-Fickian diffusion-release mechanism indicated both swelling and diffusion. The anomalous transport within the drug-release profile pointed to a drug-discharge mechanism that combined both diffusion and erosion. The viability studies showed a growth of Lactobacilli fermentum in both the polymer blend and the nanofiber formulation that was retained post-storage at 25 °C for 30 days. The developed electrospun scaffolds for the intravaginal delivery of Lactobacilli spp., along with a tenside and metronidazole for the management of bacterial vaginosis, provide a novel tool for the treatment and management of recurrent vaginal infection.
RESUMO
Curcumin is a primary polyphenol of the rhizomatous perennial plant called Curcuma Longa. Curcumin interferes favorably with the cellular events that take place in the inflammatory and proliferative stages of wound healing, hence its importance in skin regeneration and wound healing. Curcumin is however lipophilic, and this must be considered in the choice of its drug delivery system. Liposomes are spherical vesicles with bi-lipid layers. Liposomes can encapsulate both lipophilic and hydrophilic drugs, hence their suitability as an ideal drug delivery system for curcumin. There is, nevertheless, a tendency for liposomes to be unstable and have low encapsulation efficiency if it is not formulated properly. Formulation optimization of curcumin-loaded liposomes was studied by the application of artificial neural network (ANN) to improve encapsulation efficiency and flux of the liposomes. The input factors selected for optimization of the formulation were sonication time, hydration volume, and lipid/curcumin ratio. The response variables were encapsulation efficiency and flux. The maximum encapsulation efficiency and flux were obtained using lipid/curcumin ratio of 4.35, sonicator time of 15 min, and hydration volume of 25 mL. The maximum encapsulation efficiency and flux predicted were 100% and 51.23 µg/cm2/h, respectively. The experimental values were 99.934% and 51.229 µg/cm2/h, respectively. Curcumin-loaded liposome formulation is a promising drug delivery system in the pharmaceutical industry when formulated using optimized parameters derived from ANN statistically designed models.
RESUMO
Bacterial vaginosis, a polymicrobial clinical syndrome characterized by a shift in healthy vaginal microbiota due to bacterial colonization, is characterized by high recurrence rates after conventional treatment with an antimicrobial agent. This has necessitated the need to develop a formulation that has the potential to ensure Lactobacilli viability and bacterial clearance. This study seeks to develop and optimize a layered suppository using a five-level central composite design to ensure optimized metronidazole release and lactic acid viability. Layered suppositories were formulated using the fusion method using polyethylene glycol blend 1500/4000 and Ovucire® as suppository bases. Lactobacillus fermentum was incorporated in the molten mass before molding the solid body suppositories into the cavity of hollow-type suppositories and sealing the molten excipients. Artificial neural network model predictions for product optimization showed high predictive capacity, closely resembling experimental observations. The highest disintegration time recorded was 12.76 ± 0.37 min, with the optimized formulations showing lower times of 5.93 ± 0.98 min and an average weight of 1.17 ± 0.07 g. Histopathological observations determined high compatibility of suppositories with vaginal cells with no distortion or wearing of the vagina epithelium. This optimized formulation provides a safe and promising alternative to conventional suppositories in the treatment and prevention of the recurrence of bacterial vaginosis.