Comparison of in vitro antibacterial activity of streptomycin-diclofenac loaded composite biomaterial dressings with commercial silver based antimicrobial wound dressings

In vitro culture and morphology of Neoechinorhynchus buttnerae (Eoacanthocephala: Neoechinorhynchidae) collected from the intestine of tambaqui (Colossoma macropomum) farmed in the Brazilian Amazon

The tambaqui (Colossoma macropomum) is a species of great economic importance for fish farming in the Brazilian Amazon, and acanthocephaliasis caused by Neoechinorhynchus buttnerae (Golvan 1956) represents an obstacle to its production due to it causing severe morphological damage to the intestinal mucosa, thus impairing the absorption of nutrients and causing weight loss in the fish. Therefore, the establishment of in vitro protocols for evaluation of anthelmintic drugs is the first step to development of effective measures for in vivo control of this endoparasite. The present study evaluated the in vitro survival of N. buttnerae maintained in Eagle's minimum essential medium under different culture conditions. Three assays were carried out to evaluate whether temperature, supplementation with the antibiotics penicillin and streptomycin, and culture medium replacement or no replacement would influence the motility and morphology of the acanthocephalans. The results of the Kaplan-Meier analysis indicated that the use of culture in minimum essential medium together with penicillin and streptomycin prolonged the parasite's survival when kept at temperatures of 24 °C or 28 °C. We describe herein for first time an alternative protocol that is ideal for the in vitro culture of N. buttnerae. As such, this protocol ensures greater reliability in further in vitro studies with N. buttnerae.

pH-sensitive bilayer electrospun nanofibers based on ethyl cellulose and Eudragit S-100 as a dual delivery system for treatment of the burn wounds; preparation, characterizations, and in-vitro/in-vivo assessment

A pH-sensitive bilayer electrospun nanofibrous mat containing both antibiotic (gentamicin sulfate, GEN) and non-steroidal anti-inflammatory (diclofenac sodium, DIC) drugs was fabricated for burn wound dressing by electrospinning technique, in which ethyl cellulose (EC) and ethyl cellulose/Eudragit S-100 (EC/ES-100) formed the top and bottom layers, respectively. The fabricated pH-sensitive bilayer electrospun nanofibrous mats were characterized from aspects of both structure and efficiency. Physicochemical properties were investigated via SEM, FTIR, and TGA. The swelling ratio and in vitro drug release of the fabricated nanofibrous mats were studied in different pHs. MTT was applied to assess the safety of the fiber mats. Finally, the in vivo efficiency of the designed pH-sensitive bilayer electrospun nanofibrous mats was examined on the male Wistar rats. Based on the histological analysis and wound healing test (in vivo animal experiments), the (ES100/EC-DIC/GEN)-(EC) pH-sensitive bilayer nanofibrous mat displayed faster wound healing than other bilayer nanofibrous mat. As a result, (ES100/EC-DIC/GEN)-(EC) bilayer nanofibrous mat with pH-responsion could accelerate the burn wound healing process via decreasing the adverse effects of GEN and DIC as topical antimicrobial and anti-inflammatory agents, receptively.

Treatment performance and microbial community structure in an aerobic granular sludge sequencing batch reactor amended with diclofenac, erythromycin, and gemfibrozil

This study characterizes the effects of three commonly detected pharmaceuticals-diclofenac, erythromycin, and gemfibrozil-on aerobic granular sludge. Approximately 150 μg/L of each pharmaceutical was fed in the influent to a sequencing batch reactor for 80 days, and the performance of the test reactor was compared with that of a control reactor. Wastewater treatment efficacy in the test reactor dropped by approximately 30-40%, and ammonia oxidation was particularly inhibited. The relative abundance of active Rhodocyclaceae, Nitrosomonadaceae, and Nitrospiraceae families declined throughout exposure, likely explaining reductions in wastewater treatment performance. Pharmaceuticals were temporarily removed in the first 12 days of the test via both sorption and degradation; both removal processes declined sharply thereafter. This study demonstrates that aerobic granular sludge may successfully remove pharmaceuticals in the short term, but long-term tests are necessary to confirm if pharmaceutical removal is sustainable.

Antibiotic-Loaded Psyllium Husk Hemicellulose and Gelatin-Based Polymeric Films for Wound Dressing Application

Wound infections are one of the major reasons for the delay in the healing of chronic wounds and can be overcome by developing effective wound dressings capable of absorbing exudate, providing local antibiotic release, and improving patient comfort. Arabinoxylan (AX) is a major hemicellulose present in psyllium seed husk (PSH) and exhibits promising characteristics for developing film dressings. Herein, AX-gelatin (GL) films were prepared by blending AX, gelatin (GL), glycerol, and gentamicin (antibiotic). Initially, the optimal quantities of AX, GL, and glycerol for preparing transparent, bubble-free, smooth, and foldable AX-GL films were found. Physiochemical, thermal, morphological, drug release, and antibacterial characteristics of the AX-GL films were evaluated to investigate their suitability as wound dressings. The findings suggested that the mechanical, water vapor transmission, morphological, and expansion characteristics of the optimized AX-GL films were within the required range for wound dressing. The results of Fourier-transform infrared (FTIR) analyses suggested chemical compatibility among the ingredients of the films. In in vitro drug release and antibacterial activity experiments, gentamicin (GM)-loaded AX-GL films released approximately 89% of the GM in 24 h and exhibited better antibacterial activity than standard GM solution. These results suggest that AX-GL films could serve as a promising dressing to protect against wound infections.

Nanomaterials for Wound Dressings: An Up-to-Date Overview

As wound healing continues to be a challenge for the medical field, wound management has become an essential factor for healthcare systems. Nanotechnology is a domain that could provide different new approaches concerning regenerative medicine. It is worth mentioning the importance of nanoparticles, which, when embedded in biomaterials, can induce specific properties that make them of interest in applications as materials for wound dressings. In the last years, nano research has taken steps to develop molecular engineering strategies for different self-assembling biocompatible nanoparticles. It is well-known that nanomaterials can improve burn treatment and also the delayed wound healing process. In this review, the first-line of bioactive nanomaterials-based dressing categories frequently applied in clinical practice, including semi-permeable films, semipermeable foam dressings, hydrogel dressings, hydrocolloid dressings, alginate dressings, non-adherent contact layer dressings, and multilayer dressings will be discussed. Additionally, this review will highlight the lack of high-quality evidence and the necessity for future advanced trials because current wound healing therapies generally fail to provide an excellent clinical outcome, either structurally or functionally. The use of nanomaterials in wound management represents a unique tool that can be specifically designed to closely reflect the underlying physiological processes in tissue repair.

Occurrence, interactive effects and ecological risk of diclofenac in environmental compartments and biota - a review

Diclofenac, a nonsteroidal anti-inflammatory drug has turned into a contaminant of emerging concern; hence, it was included in the previous Watch List of the EU Water Framework Directive. This review paper aims to highlight the metabolism of diclofenac at different trophic levels, its occurrence, ecological risks, and interactive effects in the water cycle and biota over the past two decades. Increased exposure to diclofenac not only raises health concerns for vultures, aquatic organisms, and higher plants but also causes serious threats to mammals. The ubiquitous nature of diclofenac in surface water (river, lake canal, estuary, and sea) is compared with drinking water, groundwater, and wastewater effluent in the environment. This comprehensive survey from previous studies suggests the fate of diclofenac in wastewater treatment plants (WWTPs) and may predict its persistence in the environment. This review offers evidence of fragmentary available data for the water environment, soil, sediment, and biota worldwide and supports the need for further data to address the risks associated with the presence of diclofenac in the environment. Finally, we suggest that the presence of diclofenac and its metabolites in the environment may represent a high risk because of their synergistic interactions with existing contaminants, leading to the development of drug-resistant strains and the formation of newly emerging pollutants.

Effects and formulation of silver nanoscaffolds on cytotoxicity dependent ion release kinetics towards enhanced excision wound healing patterns in Wistar albino rats

Wound tissue regeneration and angiogenesis are dynamic processes that send physiological signals to the body. Thus, designing novel nanoscaffolds by understanding their surface modifications and toxicological response in a biological system with a potent anti-inflammatory response is a viable solution. In this respect, inspired by the surface chemistry, in the present work we focus on the chemical optimization of silver nanoscaffolds using surface cappings in order to understand their kinetic release behaviour in simulated wound fluids (SWF), to analyze their blood compatibility in human lymphocytes and erythrocytes and then embed them in a chitosan-agarose matrix (CAM) as a productive drug delivery system to evaluate in vivo excision wound tissue regeneration efficiency in Wistar rats. In this regard, polyvinyl alcohol capped silver nanocomposites (PVA-AgNPs) exhibit a dominant antibacterial efficacy with the sustained and controlled release of silver ions and percentage cell mortality and percentage hemolysis of only 10% and 16% compared with uncapped-AgNPs or silver bandaids (SBDs). Also, PVA-AgNP impregnated CAM (PVA-CAM) shows positive effects through their anti-inflammatory and angiogenic properties, with a nearly 95% healing effect within 9 days. The complete development of collagen and fibroblast constituents was also monitored in PVA-CAM by hematoxylin & eosin (H & E) and Masson trichrome (MT) staining. These results provide a clear insight into the development of a potent therapeutic formulation using CAM as a scaffold incorporated with surface functionalized PVA-AgNPs as a bioeffective and biocompatible polymer for the fabrication of efficacious silver wound dressing scaffolds in clinical practice.