Despite the advantages presented by synthetic polymers such as strength and durability, the lack of biodegradability associated with the persistence in the environment for a long time turned the attention of researchers to natural polymers. Being biodegradable, biopolymers proved to be extremely beneficial to the environment. At present, they represent an important class of materials with applications in all economic sectors, but also in medicine. They find applications as absorbers, cosmetics, controlled drug delivery, tissue engineering, etc. Chitosan is one of the natural polymers which raised a strong interest for researchers due to some exceptional properties such as biodegradability, biocompatibility, nontoxicity, non-antigenicity, low-cost and numerous pharmacological properties as antimicrobial, antitumor, antioxidant, antidiabetic, immunoenhancing. In addition to this, the free amino and hydroxyl groups make it susceptible to a series of structural modulations, obtaining some derivatives with different biomedical applications. This review approaches the physico-chemical and pharmacological properties of chitosan and its derivatives, focusing on the antimicrobial potential including mechanism of action, factors that influence the antimicrobial activity and the activity against resistant strains, topics of great interest in the context of the concern raised by the available therapeutic options for infections, especially with resistant strains.

Natural deep eutectic solvents (NADES)-hydroxypropyl cellulose (HPC) self-assembled gels with potential for pharmaceutical applications are prepared. FT-IR, ¹HNMR, DSC, TGA and rheology measurements revealed that hydrogen bond acceptor–hydrogen bond donor interactions, concentration of NADES and the water content influence significantly the physico-chemical characteristics of the studied gel systems. HPC-NADES gel compositions have thermal stabilities lower than HPC and higher than NADES components. Thermal transitions reveal multiple glass transitions characteristic of phase separated systems. Flow curves evidence shear thinning (pseudoplastic) behavior. The flow curve shear stress vs. shear rate were assessed by applying Bingham, Herschel–Bulkley, Vocadlo and Casson rheological models. The proposed correlations are in good agreement with experimental data. The studied gels evidence thermothickening behavior due to characteristic LCST (lower critical solution temperature) behavior of HPC in aqueous systems and a good biocompatibility with normal cells (human gingival fibroblasts). The order of antibacterial and antifungal activities (S.aureus, E.coli, P. aeruginosa and C. albicans) is as follows: citric acid >lactic acid > urea > glycerol, revealing the higher antibacterial and antifungal activities of acids.

Natural compounds have been used as wound-healing promoters and are also present in today’s clinical proceedings. In this research, different natural active components such as propolis, Manuka honey, insulin, L-arginine, and Calendula officinalis infusion were included into hyaluronic acid/poly(ethylene)oxide-based electrospun nanofiber membranes to design innovative wound-dressing biomaterials. Morphology and average fiber diameter were analyzed by scanning electron microscopy. Chemical composition was proved by Fourier transform infrared spectroscopy, which indicated successful incorporation of the active components. The nanofiber membranes with propolis and Calendula officinalis showed best antioxidant activity, cytocompatibility, and antimicrobial properties against pathogen strains Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa and had an average diameter of 217 ± 19 nm with smooth surface aspect. Water vapor transmission rate was in agreement with the range suitable for preventing infections or wound dehydration (~5000 g/m² 24 h). Therefore, the developed hyaluronic acid/poly(ethylene)oxide nanofibers with additional natural components showed favorable features for clinical use as wound dressings.

Acute heart failure (AHF) is a life-threatening condition with high morbidity and mortality. Even though this pathology has been extensively researched, there are still challenges in establishing an accurate and early diagnosis, determining the long- and short-term prognosis and choosing a targeted therapeutic strategy. The use of reliable biomarkers to support clinical judgment has been shown to improve the management of AHF patients. Despite a large pool of interesting candidate biomarkers, endothelin-1 (ET-1) appears to be involved in multiple aspects of AHF pathogenesis that include neurohormonal activation, cardiac remodeling, endothelial dysfunction, inflammation, atherosclerosis and alteration of the renal function. Since its discovery, numerous studies have shown that the level of ET-1 is associated with the severity of symptoms and cardiac dysfunction in this pathology. The purpose of this paper is to review the existing information on ET-1 and answer the question of whether this neurohormone could be a promising biomarker in AHF.

The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6) showed the highest swelling ratio (197%) and the highest biodegradation rate (63.04%) in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5) which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity.

The intricate relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the cardiovascular system is an extensively studied pandemic topic, as there is an ever-increasing amount of evidence that reports a high prevalence of acute cardiac injury in the context of viral infection. In patients with Coronavirus disease 2019, COVID-19, a significant increase in serum levels of cardiac troponin or other various biomarkers was observed, suggesting acute cardiac injury, thus predicting both a severe course of the disease and a poor outcome. Pathogenesis of acute cardiac injury is not yet completely elucidated, though several mechanisms are allegedly involved, such as a direct cardiomyocyte injury, oxygen supply-demand inequity caused by hypoxia, several active myocardial depressant factors during sepsis, and endothelial dysfunction due to the hyperinflammatory status. Moreover, the increased levels of plasma cytokines and catecholamines and a significantly enhanced prothrombotic environment may lead to the destabilization and rupture of atheroma plaques, subsequently triggering an acute coronary syndrome. In the present review, we focus on describing the epidemiology, pathogenesis, and role of biomarkers in the diagnosis and prognosis of patients with acute cardiac injury in the setting of the COVID-19 pandemic. We also explore some novel therapeutic strategies involving immunomodulatory therapy, as well as their role in preventing a severe form of the disease, with both the short-term outcome and the long-term cardiovascular sequelae being equally important in patients with SARS-CoV-2 induced acute cardiac injury.