Biocompatible gels of chitosan-buriti oil for potential wound healing applications

The buriti oil (Mauritia flexuosa L.) can be associated with polymeric matrices for biomedical applications. This study aimed to evaluate the e ect of chitosan gel (CG) associated with buriti oil (CGB) as a healing agent. The fatty acids and volatile compounds composition of buriti oil were performed and the composite gels were characterized using FTIR and thermal analysis. Biological tests including antimicrobial, antioxidant, anti-inflammatory and healing e ects were also investigated. Buriti oil is composed of oleic and palmitic acids, and the main volatile compounds were identified. The buriti oil did not show antimicrobial activity, on the other hand, the composite gel (chitosan and oil) proved to be e cient against Staphylococcus aureus and Klebsiella pneumonia at the 10 mg/mL. Similar behavior was observed for antioxidant activity, determined by the -carotene bleaching assay, composite gels presenting higher activity and buriti oil showed anti-inflammatory activity, which may be related to the inhibition of the release of free radicals. Regarding wound healing performed using in vivo testing, the composite gel (CGB) was found to promote faster and complete wound retraction. The results indicated that the gel chitosan–buriti oil has a set of properties that improve its antibacterial, antioxidant and healing action, suggesting that this material can be used to treat skin lesions.Maria Onaira Gonçalves Ferreira acknowledges the Coordination for the Improvement of Higher Education Personnel, the Brazilian Ministry of Education, financial support for the scholarship, and other authors acknowledge to National Council for Scientific and Technological Development (CNPQ) and Piauí State Research Support Foundation (FAPEPI).info:eu-repo/semantics/publishedVersio

HAp/β-TCP Biphasic Ceramics Obtained by the Pechini Method: An Antibacterial Approach

Calcium phosphates (CaPs) have broad applications in biomedicine, with the most used phases being hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) due to their similarity with natural bone. There are several methods for obtaining CaPs. However, the Pechini method attracts much attention due to its advantages: homogeneous molecular mixing, obtaining nanocrystalline particles, low processing temperature, generating nanometric particles, and simplicity. However, this method is little discussed for the synthesis of CaPs. This work aimed to synthesize CaPs using the Pechini method, analyzing the antibacterial properties. The samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG/DTG), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The XRD confirmed obtaining the biphasic ceramic of HAp, with no other phase as an impurity, where the ratio between citric acid and ethylene glycol (AC/EG) influenced the percentage of HAp phases and β-TCP formed. Thermogravimetric analysis showed a mass loss of approximately 7%. SEM observed the formation of post-agglomerates and irregular shapes. The bacteriological test was satisfactory. The samples showed above 25% inhibition for the growth of Staphylococcus aureus and Escherichia coli bacteria

HAp/β-TCP Biphasic Ceramics Obtained by the Pechini Method: An Antibacterial Approach

Calcium phosphates (CaPs) have broad applications in biomedicine, with the most used phases being hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) due to their similarity with natural bone. There are several methods for obtaining CaPs. However, the Pechini method attracts much attention due to its advantages: homogeneous molecular mixing, obtaining nanocrystalline particles, low processing temperature, generating nanometric particles, and simplicity. However, this method is little discussed for the synthesis of CaPs. This work aimed to synthesize CaPs using the Pechini method, analyzing the antibacterial properties. The samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG/DTG), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The XRD confirmed obtaining the biphasic ceramic of HAp, with no other phase as an impurity, where the ratio between citric acid and ethylene glycol (AC/EG) influenced the percentage of HAp phases and β-TCP formed. Thermogravimetric analysis showed a mass loss of approximately 7%. SEM observed the formation of post-agglomerates and irregular shapes. The bacteriological test was satisfactory. The samples showed above 25% inhibition for the growth of Staphylococcus aureus and Escherichia coli bacteria

Antimicrobial efficacy of building material based on ZnO/palygorskite against gram-negative and gram-positive bacteria

This study investigated ZnO nanoparticles immobilized in palygorskite clay mineral (Pal) that acted as an inorganic antimicrobial agent in a commercial mortar aiming to control microorganisms and improve safety and stability for building applications. ZnO/Pal nanocomposites were obtained by sol-gel methods at pH 7 and 11 and were calcined at 250 °C and 400 °C to evaluate different synthesis parameters. The mortar/ZnO/Pal composite was obtained using 5% (by weight) ZnO/Pal hybrid mixed with a commercial mortar. The results show that pH and calcination temperature influenced the properties of ZnO/Pal. ZnO was observed in the ZnO/Pal samples during the wurtzite phase by analyzing the XRD patterns. FTIR spectra illustrated the interactions between ZnO nanoparticles and the fibrous clay mineral. TG-DTG analysis showed the thermal events of Pal before and after zinc incorporation. Scanning electron microscopy (SEM) evaluated ZnO morphology as spherical in shape and dispersed on the fibers of the clay minerals, which presented needle-like morphology. ZnO/Palygorskite showed a possible antibacterial effect when used in mortar formulation. The mortar/ZnO/Pal composites were effective against Escherichia coli and Staphylococcus aureus bacteria when tested by the direct contact method in darkness and in visible light and could be an alternative antimicrobial material for building surfaces.info:eu-repo/semantics/publishedVersio

TiO2/Karaya Composite for Photoinactivation of Bacteria

TiO2/Karaya composite was synthesized by the sol-gel method for the photoinactivation of pathogens. This is the first time that we have reported this composite for an antimicrobial approach. The structure, morphology, and optical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-rays (EDS), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance, and the surface area was characterized by the BET method. The XRD and EDS results showed that the TiO2/Karaya composite was successfully stabilized by the crystal structure and pore diameter distribution, indicating a composite of mesoporous nature. Furthermore, antibacterial experiments showed that the TiO2/Karaya composite under light was able to photoinactivate bacteria. Therefore, the composite is a promising candidate for inhibiting the growth of bacteria

Preparation and Release of Antibacterial Na-mica-4/Chlorhexidine Nanocomposites

High charge swelling micas are layered silicates used in adsorption of several inorganic and organic species. In this study, we evaluated the adsorption of chlorhexidine digluconate on highly charge mica Na-mica-4. Drug release and antibacterial action against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) using the direct contact test for mica/chlorhexidine hybrids were evaluated. The hybrids were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential measurements, CHN elemental analysis, and scanning electron microscopy. Chlorhexidine interacts successfully with the mica surface. The maximum amount of chlorhexidine incorporated was 583 mg g−1, and the characterizations indicated that electrostatic attraction between the protonated amino group of the drug and the negative surface of clay was predominant in the formation of hybrids. Release kinetics study indicated that 80% of the drug release occurred in the first 12 h. The antibacterial test proved to be dependent on the time of chlorhexidine release, reaching 100% inhibition against S. aureus and E. coli after 0.5 h and 6 h, respectively.Universidad de Sevilla 2022/00000444Gobierno de España 2023/0000031

Hydrogel Based on Nanoclay and Gelatin Methacrylate Polymeric Matrix as a Potential Osteogenic Application

A nanocomposite hydrogel has potentially applicability in the induction of osteogenesis. The hydrogel was synthesized using 1% gelatin methacrylate (GelMA), a biodegradable and bioactive polymer containing the structure of gelatin, denatured collagen derived from the extracellular bone matrix, and 6% laponite (Lap), a synthetic phyllosilicate of nanosized particles. Initially, 0.6 g of Lap was added to deionized water, and then a solution of GelMA/Igarcure was added under stirring and UV light for crosslinking. The spectra in the Fourier-transform infrared region showed bands that indicate the interaction between gelatin and methacrylate anhydride. X-ray diffraction patterns confirmed the presence of Lap and GelMA in the hydrogel. The thermogravimetric analysis suggested an increase in the thermal stability of the hydrogel with the presence of clay mineral. Rheological analysis showed that the hydrogel had a viscosity that allowed its injectability. The hydrogel did not show acute toxicity at any of the concentrations tested according to the Artemia salina lethality test. It showed cell viability more significant than 80% in the MTT test, which makes it suitable for in vivo osteogenic induction tests. The cell differentiation test showed the differentiation of stem cells into osteogenic cells. It indicates a material with the potential for osteogenic induction and possible application in bone tissue engineering

Controlled Release of Curcumin from Hydrogels: Biomedical Applications with a Focus on Neurodegenerative Diseases

A lot of works have shown Curcumin (Cur) as a potential candidate in the treatment of neurodegenerative diseases (NDDs) such as atherosclerosis, stroke, Huntington’s, Alzheimer’s, and Parkinson’s. The therapeutic potential of Cur in NDDs has been linked to its antioxidant, anti-inflammatory, and anti-protein aggregation effects. However, one of the main factors that have limited the application of Cur is the scarcity of clinical trials to evaluate its therapeutic efficacy due to its extremely low aqueous solubility, instability, low oral bioavailability associated with the low aqueous solubility, rapid metabolism, and elimination from the bloodstream. Hydrogel matrixes are an interesting way for Cur carrying, mainly to protect the Cur against instability and enhance the low bioavailability. The encapsulation of Cur in polymeric micelles and hydrogels is an example of an important strategy to facilitate its delivery and release in the human body to protect against several diseases, including in NDDs. Therefore, 3D matrices of hydrogels, made up of polymers, are materials with characteristics and requirements suitable for applications such as drug delivery systems (DDS). This chapter centers around the neuroprotective properties of Cur and its utilization in both the treatment and prevention of NDDs. Almost 180 references are cited ca. 120 of them published in the last 5 years