Alginate hydrogel dressings for advanced wound management.

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

https://www.mdpi.com/2073-4360/12/10/2417/pdf

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders.

Alginate is a polysaccharide of natural origin, which shows outstanding properties of biocompatibility, gel forming ability, non-toxicity, biodegradability and easy to process. Due to these excellent properties of alginate, sodium alginate, a hydrogel form of alginate, oxidized alginate and other alginate based materials are used in various biomedical fields, especially in drug delivery, wound healing and tissue engineering. Alginate can be easily processed as the 3D scaffolding materials which includes hydrogels, microcapsules, microspheres, foams, sponges, and fibers and these alginate based bio-polymeric materials have particularly used in tissue healing, healing of bone injuries, scars, wound, cartilage repair and treatment, new bone regeneration, scaffolds for the cell growth. Alginate can be easily modified and blended by adopting some physical and chemical processes and the new alginate derivative materials obtained have new different structures, functions, and properties having improved mechanical strength, cell affinity and property of gelation. This can be attained due to combination with other different biomaterials, chemical and physical crosslinking, and immobilization of definite ligands (sugar and peptide molecules). Hence alginate, its modified forms, derivative and composite materials are found to be more attractive towards tissue engineering. This article provides a comprehensive outline of properties, structural aspects, and application in tissue engineering.

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Alginate and its application to tissue engineering

Silver nanoparticles (AgNPs) represent one of the most explored categories of nanomaterials for new and improved biomaterials and biotechnologies, with impressive use in the pharmaceutical and cosmetic industry, anti-infective therapy and wound care, food and the textile industry. Their extensive and versatile applicability relies on the genuine and easy-tunable properties of nanosilver, including remarkable physicochemical behavior, exceptional antimicrobial efficiency, anti-inflammatory action and antitumor activity. Besides commercially available and clinically safe AgNPs-based products, a substantial number of recent studies assessed the applicability of nanosilver as therapeutic agents in augmented and alternative strategies for cancer therapy, sensing and diagnosis platforms, restorative and regenerative biomaterials. Given the beneficial interactions of AgNPs with living structures and their nontoxic effects on healthy human cells, they represent an accurate candidate for various biomedical products. In the present review, the most important and recent applications of AgNPs in biomedical products and biomedicine are considered.

https://www.mdpi.com/2079-4991/10/11/2318/pdf

An Updated Review on Silver Nanoparticles in Biomedicine.

This review offers a systematic discussion about nanotoxicology and nanosafety associated with nanomaterials during manufacture and further biomedical applications A detailed introduction on nanomaterials and their most frequently uses, followed by the critical risk aspects related to regulatory uses and commercialization, is provided Moreover, the impact of nanotoxicology in research over the last decades is discussed, together with the currently available toxicological methods in cell cultures (in vitro) and in living organisms (in vivo) A special focus is given to inorganic nanoparticles such as titanium dioxide nanoparticles (TiO2NPs) and silver nanoparticles (AgNPs) In vitro and in vivo case studies for the selected nanoparticles are discussed The final part of this work describes the significance of nano-security for both risk assessment and environmental nanosafety “Safety-by-Design” is defined as a starting point consisting on the implementation of the principles of drug discovery and development The concept “Safety-by-Design” appears to be a way to “ensure safety”, but the superficiality and the lack of articulation with which it is treated still raises many doubts Although the approach of “Safety-by-Design” to the principles of drug development has helped in the assessment of the toxicity of nanomaterials, a combination of scientific efforts is constantly urgent to ensure the consistency of methods and processes This will ensure that the quality of nanomaterials is controlled and their safe development is promoted Safety issues are considered strategies for discovering novel toxicological-related mechanisms still needed to be promoted

https://repositorium.sdum.uminho.pt/bitstream/1822/65854/1/document_53804_1.pdf

Nanotoxicology and Nanosafety: Safety-by-Design and Testing at a Glance

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430–450 nm in the ultraviolet-visible (UV–Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT–IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm−1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

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R. L. C. de Albuquerque Junior

Papers

Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo

Double membrane based on lidocaine-coated polymyxin-alginate nanoparticles for wound healing: In vitro characterization and in vivo tissue repair