Bioengineered mannan sulphate capped silver nanoparticles for accelerated and targeted wound healing: Physicochemical and biological investigations

Naturally and Chemically Sulfated Polysaccharides in Drug Delivery Systems

Sulfated polysaccharides have always attracted much attention in food, cosmetic and pharmaceutical industries. These polysaccharides can be obtained from natural sources such as seaweeds (agarans, carrageenans, fucoidans, mannans and ulvans), or animal tissues (glucosaminoglycans). In the last few years, several neutral or cationic polysaccharides have been sulfated by chemical methods and anionic or amphoteric derivatives were obtained, respectively, for drug delivery and other biomedical applications. An important characteristic of sulfated polysaccharides in this field is that they can associate with cationic drugs generating polyelectrolyte-drug complexes, or with cationic polymers to form interpolyelectrolyte complexes, with hydrogel properties that expand even more their applications. The aims of this chapter are to present the structural characteristics of these polysaccharides, to describe the methods of sulfation applied and to review extensively and discuss developments in their use or their role in interpolyelectrolyte complexes in drug delivery platforms. A variety of pharmaceutical dosage forms which were developed and administered by multiple routes (oral, transdermal, ophthalmic, and pulmonary, among others) to treat diverse pathologies were considered. Different IPECs were formed employing these sulfated polysaccharides as the anionic component. The most widely investigated is κ-carrageenan. Chitosan is usually employed as a cationic polyelectrolyte, with a variety of sulfated polysaccharides, besides the applications of chemically sulfated chitosan. Although chemical sulfation is often carried out in neutral polysaccharides and, to a less extent, in cationic ones, examples of oversulfation of naturally sulfated fucoidan have been found which improve its drug binding capacity and biological properties.

A Review of Metal Nanoparticles Embedded in Hydrogel Scaffolds for Wound Healing In Vivo

An evolving field, nanotechnology has made its mark in the fields of nanoscience, nanoparticles, nanomaterials, and nanomedicine. Specifically, metal nanoparticles have garnered attention for their diverse use and applicability to dressings for wound healing due to their antimicrobial properties. Given their convenient integration into wound dressings, there has been increasing focus dedicated to investigating the physical, mechanical, and biological characteristics of these nanoparticles as well as their incorporation into biocomposite materials, such as hydrogel scaffolds for use in lieu of antibiotics as well as to accelerate and ameliorate healing. Though rigorously tested and applied in both medical and non-medical applications, further investigations have not been carried out to bring metal nanoparticle-hydrogel composites into clinical practice. In this review, we provide an up-to-date, comprehensive review of advancements in the field, with emphasis on implications on wound healing in in vivo experiments.

Exopolysaccharide from the yeast Papiliotrema terrestris PT22AV for skin wound healing

INTRODUCTION

Exopolysaccharides (EPSs) are high-value functional biomaterials mainly produced by bacteria and fungi, with nutraceutical, therapeutic and industrial potentials.

OBJECTIVES

This study sought to characterize and assess the biological properties of the EPS produced by the yeast Papiliotrema terrestris PT22AV.

METHODS

After extracting the yeast's DNA and its molecular identification, the EPS from P. terrestris PT22AV strain was extracted and its physicochemical properties (structural, morphological, monosaccharide composition and molecular weight) were characterized. The EPS's in vitro biological activities and in vivo wound healing potential were also evaluated.

RESULTS

The obtained EPS was water-soluble and revealed an average molecular weight (M_w) of 202 kDa. Mannose and glucose with 97% and 3% molar percentages, respectively, constituted the EPS. In vitro antibacterial activity analysis of the extracted EPS exhibited antibacterial activity (>80%) against Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis at a concentration of 2 mg/mL. The EPS showed cytocompatibility against the human fibroblast and macrophage cell lines and the animal studies showed a dose-dependent wound healing capacity of the EPS with higher wound closure at 10 mg/mL compared to negative and positive control after 14 days.

CONCLUSION

The EPS from P. terrestris PT22AV could serve as a promising source of biocompatible macromolecules with potential for skin wound healing.

Understanding the Potential Role and Delivery Approaches of Nitric Oxide in Chronic Wound Healing Management

Nitric oxide (NO) is a promising pharmaceutical component that has vasodilator, anti-bacterial, and wound healing activities. Chronic ulcers are non-healing disorders that are generally associated with distortion of lower limbs. Among the severe consequence derivatives of these diseases are the problems of chronic wound progression. NO, which is categorized as the smallest gaseous neurotransmitter, has beneficial effects in different phases of chronic inflammation. The defensive mechanism of NO is found useful in several severe conditions, such as gestational healing, gastrointestinal healing, and diabetic healing. The current review presents an updated collection of literature about the role of NO in chronic ulcers due to the prevalence of diabetes, DPN, and diabetic foot ulcers, and because of the lack of available effective treatments to directly address the pathology contributing to these conditions, novel treatments are being sought. This review also collects information about deficiency of NO synthase in diabetic patients, leading to a lack of vascularization of the peripheral nerves, which causes diabetic neuropathy, and this could be treated with vasodilators such as nitric oxide. Apart from the pharmacological mechanism of NO, the article also reviewed and analyzed to elucidate the potential of transdermal delivery of NO for the treatment of chronic ulcers.

Silver Nanoparticle-Coated Ethyl Cellulose Inhibits Tumor Necrosis Factor-α of Breast Cancer Cells

Introduction

Cancer is one of the leading causes of death worldwide. In many cases, cancer is related to the elevated expression of a significant cytokine known as tumor necrosis factor-α (TNF-α). Breast cancer in particular is linked to increased proliferation of tumor cells, high incidence of malignancies, more metastases, and generally poor prognosis for the patient. The research sought to assess the effect of silver nanoparticles reduced with ethyl cellulose polymer (AgNPs-EC) on TNF-α expression in MCF-7 human breast cancer cells.

Methods

The AgNPs-EC were produced using the green synthesis reduction method, and their formation was proofed via UV–VIS spectroscopy. Furthermore, AgNPs-EC were characterized for their size, charge, morphology, Ag ion release, and stability. The MCF-7 cells were treated with AgNPs-EC. Then, the expression of TNF-α genes was determined through PCR in real time, and protein expression was studied using ELISA.

Results

The AgNPs-EC were spherical with an average size of 150±5.1 nm and a zeta-potential of −41.4±0.98 mV. AgNPs-EC had an inhibitory effect on cytokine mRNA and protein expression levels, which suggests that they could be used safely in the fight against cancer. AgNPs-EC cytotoxicity was also found to be non-toxic to MCF-7.

Conclusion

Our data determined AgNPs-EC as a novel inhibitor of TNF-α production. These results are promising for developing novel therapeutic approaches for the future treatment of cancer with safe materials.

The impact of silver nanoparticles phytosynthesized with Viburnum opulus L. extract on the ultrastrastructure and cell death in the testis of offspring rats

AIM

To investigate the effects of prenatal exposure to AgNPs obtained by green synthesis with Viburnum opulus L. extract on the testis in male offspring rats.

MATERIAL AND METHODS

Two different doses of AgNPs (0.8 and 1.5 mg/kg b.w.) and vehicle (PBS) were administered to Wistar female rats on days 3-14 of gestation. At 6 weeks after birth, the ultrastructural changes in correlation with the amount of silver as well as the parameters of oxidative stress, inflammation and cell death mechanisms in the testis of male offspring were evaluated.

RESULTS

AgNPs administered during pregnancy crossed the placental and testicular barriers and induced oxidative stress, DNA damage and autophagy as mechanism of cell toxicity. The markers of inflammation and apoptosis decreased after AgNPs exposure while the NFkB activation increased. TEM examination revealed important ultrastructural changes of Sertoli cells, numerous vacuoles and cytoplasmic changes suggestive of the cell's evolution towards necrosis.

CONCLUSION

Phytoreduced silver nanoparticles with polyphenols from Viburnum opulus L. fruit extract, administered during the embryological development of the male gonad, have testicular toxic effects in offspring even at 6 weeks after birth.

The Impact of Engineered Silver Nanomaterials on the Immune System

Over the last decades there has been a tremendous volume of research efforts focused on engineering silver-based (nano)materials. The interest in silver has been mostly driven by the element capacity to kill pathogenic bacteria. In this context, the main area of application has been medical devices that are at significant risk of becoming colonized by bacteria and subsequently infected. However, silver nanomaterials have been incorporated in a number of other commercial products which may or may not benefit from antibacterial protection. The rapid expansion of such products raises important questions about a possible adverse influence on human health. This review focuses on examining currently available literature and summarizing the current state of knowledge of the impact of silver (nano)materials on the immune system. The review also looks at various surface modification strategies used to generate silver-based nanomaterials and the immunomodulatory potential of these materials. It also highlights the immune response triggered by various silver-coated implantable devices and provides guidance and perspective towards engineering silver nanomaterials for modulating immunological consequences.

Wound dressings functionalized with silver nanoparticles: promises and pitfalls

Infections are the main reason why most people die from burns and diabetic wounds. The clinical challenge for treating wound infections through traditional antibiotics has been growing steadily and has now reached a critical status requiring a paradigm shift for improved chronic wound care. The US Centers for Disease Control have predicted more deaths from antimicrobial-resistant bacteria than from all types of cancers combined by 2050. Thus, the development of new wound dressing materials that do not rely on antibiotics is of paramount importance. Currently, incorporating nanoparticles into scaffolds represents a new concept of 'nanoparticle dressing' which has gained considerable attention for wound healing. Silver nanoparticles (Ag-NPs) have been categorized as metal-based nanoparticles and are intriguing materials for wound healing because of their excellent antimicrobial properties. Ag-NPs embedded in wound dressing polymers promote wound healing and control microorganism growth. However, there have been several recent disadvantages of using Ag-NPs to fight infections, such as bacterial resistance. This review highlights the therapeutic approaches of using wound dressings functionalized with Ag-NPs and their potential role in revolutionizing wound healing. Moreover, the physiology of the skin and wounds is discussed to place the use of Ag-NPs in wound care into perspective.

Nanocarrier-based systems for wound healing

In general, the systems intended for the treatment and recovery of wounds, seek to act as a coating for the damaged area, maintaining an adequate level of humidity, reducing pain, and preventing the invasion and proliferation of microorganisms. Although many of the systems that are currently on the market meet the purposes mentioned above, with the arrival of nanotechnology, it has sought to improve the performance of these coatings. The variety of nano-systems that have been proposed is very extensive, including the use of very different materials (natural or synthetic) ranging from polymers or lipids to systems derived from microorganisms. With the objective of improving the performance of the systems, seeking to combat several of the problems that arise in a wound, especially when it is chronic, these materials have been combined, giving rise to nanocomposites or scaffolds. In recent years, the interest in the development of systems for the treatment of wounds is notable, which is reflected in the increase in publications related to the subject. Therefore, this document presents generalities of systems involving nanocarriers, mentioning some examples of representative systems of each case.

Green synthesis of polysaccharide-based inorganic nanoparticles and biomedical aspects

Biologically mediated inorganic nanoparticles (NPs) are considered as a green, cheap, and environmental-friendly materials, which connect the nanotechnology and biomedical sciences. Metallic NPs such as gold and silver NPs, synthesized using natural materials are an important branch of inorganic NPs with catalytic functionalities and a diverse range of biomedical applications such as antimicrobial application. Polysaccharides are excellent candidates to stabilize and control the size of NPs during the synthesis process. These polymers possess multiple binding sites, which facilitate attachment to the metal surface. As a result, polysaccharides can effectively create an organic-inorganic network of the metal NPs and confer a significant protection against aggregation and chemical modifications. This chapter discusses the methods of the preparation of polysaccharide-mediated NPs and reviews various types and diverse applications for these novel materials.

Ameliorative effect of biofabricated ZnO nanoparticles of Trianthema portulacastrum Linn. on dermal wounds via removal of oxidative stress and inflammation

An impediment in the process of wound healing can be attributed to reactive oxygen species and inflammation. The curative efficacy of green synthesized Trianthema portulacastrum Linn. zinc oxide nanoparticles (ZnOTP) was investigated in the present study for evaluation of their wound healing potential in rodents. Total phenolic and flavonoid content of ZnOTP was determined, and antioxidant potential was evaluated by the DPPH method. In vitro anti-inflammatory activity of ZnOTP was evaluated by membrane stabilization and albumin denaturation, along with proteinase inhibitory assays. The synthesized ZnOTP were characterized by UV-Visible spectroscopy, Fourier transform infrared (FT-IR) studies, Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX) studies. The wound healing potential of ZnOTP was monitored by excision and incision wound models. Analyses confirmed the formation of spherical nanoparticles of 10-20 nm size along with strong signals of zinc and oxygen atoms. Significant results (p < 0.05) of wound contraction rate, epithelialization and histopathology of the healed tissues of rats confirmed the promising wound healing property of ZnOTP. In addition, inflammatory markers, biochemical estimation such as the hydroxyproline content of granulation tissue, and the profile of antioxidant enzymes also supported the wound healing potential of ZnOTP. The present study advocated the attenuation of wounds via antioxidant and anti-inflammatory activities of a green synthesized nano-ointment.

Preparation, Characterization and Application of Polysaccharide-Based Metallic Nanoparticles: A Review

Polysaccharides are natural biopolymers that have been recognized to be the most promising hosts for the synthesis of metallic nanoparticles (MNPs) because of their outstanding biocompatible and biodegradable properties. Polysaccharides are diverse in size and molecular chains, making them suitable for the reduction and stabilization of MNPs. Considerable research has been directed toward investigating polysaccharide-based metallic nanoparticles (PMNPs) through host⁻guest strategy. In this review, approaches of preparation, including top-down and bottom-up approaches, are presented and compared. Different characterization techniques such as scanning electron microscopy, transmission electron microscopy, dynamic light scattering, UV-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and small-angle X-ray scattering are discussed in detail. Besides, the applications of PMNPs in the field of wound healing, targeted delivery, biosensing, catalysis and agents with antimicrobial, antiviral and anticancer capabilities are specifically highlighted. The controversial toxicological effects of PMNPs are also discussed. This review can provide significant insights into the utilization of polysaccharides as the hosts to synthesize MPNs and facilitate their further development in synthesis approaches, characterization techniques as well as potential applications.