Chitosan nanofiber biocomposites for potential wound healing applications: Antioxidant activity with synergic antibacterial effect

Bacterial wound infection is one of the most common nosocomial infections. The unnecessary employment of antibiotics led to raising the growth of antibiotic-resistant bacteria. Accordingly, alternative armaments capable of accelerating wound healing along with bactericidal effects are urgently needed. Considering this, we fabricated chitosan (CS)/polyethylene oxide (PEO) nanofibers armed with antibacterial silver and zinc oxide nanoparticles. The nanocomposites exhibited a high antioxidant effect and antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Besides, based on the results of the cell viability assays, the optimum concentration of ZnONPs and AgNPs in the nanofibrous mats is 0.2% w/v and 0.08% w/v respectively and had no cytotoxicity on fibroblast cells. The scaffold also showed good blood compatibility according to the effects of coagulation time. As well as significant fibroblast migration and proliferation on the wound margin, according to wound-healing assay. All in all, the developed biocompatible, antioxidant, and antibacterial Ag-ZnO NPs incorporated CS/PEO nanofibrous mats showed their potential as an effective wound dressing

Functionalization of polymers and nanomaterials for water treatment, food packaging, textile and biomedical applications: a review

AbstractThe inert nature of most commercial polymers and nanomaterials results in limitations of applications in various industrial fields. This can be solved by surface modifications to improve physicochemical and biological properties, such as adhesion, printability, wetting and biocompatibility. Polymer functionalization allows to graft specific moieties and conjugate molecules that improve material performances. In the last decades, several approaches have been designed in the industry and academia to graft functional groups on surfaces. Here, we review surface decoration of polymers and nanomaterials, with focus on major industrial applications in the medical field, textile industry, water treatment and food packaging. We discuss the advantages and challenges of polymer functionalization. More knowledge is needed on the biology behind cell–polymer interactions, nanosafety and manufacturing at the industrial scale

Engineering a platelet-rich plasma-based multifunctional injectable hydrogel with photothermal, antibacterial, and antioxidant properties for skin regeneration

Wound healing remains a significant challenge worldwide, necessitating the development of new wound dressings to aid in the healing process. This study presents a novel photothermally active hydrogel that contains platelet-rich plasma (PRP) for infected wound healing. The hydrogel was formed in a one pot synthesis approach by mixing alginate (Alg), gelatin (GT), polydopamine (PDA), and PRP, followed by the addition of CaCl2 as a cross-linker to prepare a multifunctional hydrogel (AGC-PRP-PDA). The hydrogel exhibited improved strength and good swelling properties. PDA nanoparticles (NPs) within the hydrogel endowed them with high photothermal properties and excellent antibacterial and antioxidant activities. Moreover, the hydrogels sustained the release of growth factors due to their ability to protect PRP. The hydrogels also exhibited good hemocompatibility and cytocompatibility, as well as high hemostatic properties. In animal experiments, the injectable hydrogels effectively filled irregular wounds and promoted infected wound healing by accelerating re-epithelialization, facilitating collagen deposition, and enhancing angiogenesis. The study also indicated that near-infrared light improved the healing process. Overall, these hydrogels with antibacterial, antioxidant, and hemostatic properties, as well as sustained growth factor release, show significant potential for skin regeneration in full-thickness, bacteria-infected wounds.</p

Engineering a platelet-rich plasma-based multifunctional injectable hydrogel with photothermal, antibacterial, and antioxidant properties for skin regeneration

Wound healing remains a significant challenge worldwide, necessitating the development of new wound dressings to aid in the healing process. This study presents a novel photothermally active hydrogel that contains platelet-rich plasma (PRP) for infected wound healing. The hydrogel was formed in a one pot synthesis approach by mixing alginate (Alg), gelatin (GT), polydopamine (PDA), and PRP, followed by the addition of CaCl2 as a cross-linker to prepare a multifunctional hydrogel (AGC-PRP-PDA). The hydrogel exhibited improved strength and good swelling properties. PDA nanoparticles (NPs) within the hydrogel endowed them with high photothermal properties and excellent antibacterial and antioxidant activities. Moreover, the hydrogels sustained the release of growth factors due to their ability to protect PRP. The hydrogels also exhibited good hemocompatibility and cytocompatibility, as well as high hemostatic properties. In animal experiments, the injectable hydrogels effectively filled irregular wounds and promoted infected wound healing by accelerating re-epithelialization, facilitating collagen deposition, and enhancing angiogenesis. The study also indicated that near-infrared light improved the healing process. Overall, these hydrogels with antibacterial, antioxidant, and hemostatic properties, as well as sustained growth factor release, show significant potential for skin regeneration in full-thickness, bacteria-infected wounds.</p

Engineering a platelet-rich plasma-based multifunctional injectable hydrogel with photothermal, antibacterial, and antioxidant properties for skin regeneration

Wound healing remains a significant challenge worldwide, necessitating the development of new wound dressings to aid in the healing process. This study presents a novel photothermally active hydrogel that contains platelet-rich plasma (PRP) for infected wound healing. The hydrogel was formed in a one pot synthesis approach by mixing alginate (Alg), gelatin (GT), polydopamine (PDA), and PRP, followed by the addition of CaCl2 as a cross-linker to prepare a multifunctional hydrogel (AGC-PRP-PDA). The hydrogel exhibited improved strength and good swelling properties. PDA nanoparticles (NPs) within the hydrogel endowed them with high photothermal properties and excellent antibacterial and antioxidant activities. Moreover, the hydrogels sustained the release of growth factors due to their ability to protect PRP. The hydrogels also exhibited good hemocompatibility and cytocompatibility, as well as high hemostatic properties. In animal experiments, the injectable hydrogels effectively filled irregular wounds and promoted infected wound healing by accelerating re-epithelialization, facilitating collagen deposition, and enhancing angiogenesis. The study also indicated that near-infrared light improved the healing process. Overall, these hydrogels with antibacterial, antioxidant, and hemostatic properties, as well as sustained growth factor release, show significant potential for skin regeneration in full-thickness, bacteria-infected wounds.</p

neurodegenerative diseases, tissue engineering and regenerative medicine

Funding This work was supported by grants from Fundação para a Ciência e Tecnologia (FCT) (SFRH/BD/148771/2019, 2021.05914.BD, PTDC/BTM-MAT/4738/2020), and also from the European Research Council—ERC Starting Grant (848325).A bio-inspired strategy has recently been developed for camouflaging nanocarriers with biomembranes, such as natural cell membranes or subcellular structure-derived membranes. This strategy endows cloaked nanomaterials with improved interfacial properties, superior cell targeting, immune evasion potential, and prolonged duration of systemic circulation. Here, we summarize recent advances in the production and application of exosomal membrane-coated nanomaterials. The structure, properties, and manner in which exosomes communicate with cells are first reviewed. This is followed by a discussion of the types of exosomes and their fabrication methods. We then discuss the applications of biomimetic exosomes and membrane-cloaked nanocarriers in tissue engineering, regenerative medicine, imaging, and the treatment of neurodegenerative diseases. Finally, we appraise the current challenges associated with the clinical translation of biomimetic exosomal membrane-surface-engineered nanovehicles and evaluate the future of this technology.publishersversionpublishe

Exploring biomedical applications in cancer diagnosis and therapy

The authors acknowledge the financial support from the grants 2021.05914.BD (given to D.P.) and PTDC/BTM-MAT/4738/2020 project (given to A.C.P.-S., J.C., and F.V.) from Fundacão para a Ciência e Tecnologia (FCT). J.C. acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325).Bio-mimicking principles have recently been proposed for the surface functionalization of nanoparticles (NPs). Such a strategy is based on camouflaging the NP surface with functional biomembranes to render superior biocompatibility, interfacial features, immune evasion, and active targeting properties to nanomaterials. In this area of research, cell membranes derived from a plethora of highly optimized cells, such as red blood cells, immune cells, platelets, stem cells, cancer cells, and others, have been the pioneers as coating materials. This biomimetic concept has then been applied to subcellular structures, namely extracellular vesicles and intracellular organelles. Exosomes are a nanosized extracellular vesicle subtype secreted by most cells. These phospholipid bilayer nanovesicles are surface enriched with proteins accounting for their dynamic and prominent roles in immune escape, cell-cell communication, and specific cell uptake. Their intrinsic stability, biocompatibility, reduced immunogenicity and toxicity, and specific cell-targeting features denote an optimal biological nanocarrier for biomedical applications. This review highlights the current clinical applications of exosome membrane-coated nanosystems in cancer diagnosis and therapy. These biomimetic nanosystems have emerged as a promising avenue to provide effective, highly specific, and safer cancer-targeted applications. Finally, challenges hindering their clinical application will be mentioned.publishersversionpublishe

Chitosan-based nanoscale systems for doxorubicin delivery:Exploring biomedical application in cancer therapy

Abstract Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS‐based nanoparticles (CS‐NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS‐NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P‐glycoprotein (P‐gp) to reverse drug resistance. These nanoarchitectures can provide co‐delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co‐loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid‐, carbon‐, polymeric‐ and metal‐based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS‐NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS‐NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH‐sensitive release of DOX can occur. Furthermore, redox‐ and light‐responsive CS‐NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS‐NPs, we expect to soon see significant progress towards clinical translation

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

Abstract The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Polysaccaharides based systems towards regenerative medicine and drug delivery applications

Infection is a crucial and generally unsolved issue in tissue engineering applications such as in wound healing and bone regeneration. In this study, we have prepared different antibacterial platforms containing hyaluronic acid and silver nanoparticles. Silver nanoparticles (Ag NPs) were biosynthesized by a microwave-assisted green technique using corn silk extract in an organic solvent-free medium. The thermosensitive and injectable hydrogels were prepared and their potential use as wound care materials and bone regeneration were investigated. Rheological analysis demonstrated that the nanocomposites have good mechanical properties with gelation temperature close to the body temperature; hence, they can be easily administrated locally on wounded skins and bone defect. The samples exhibited antibacterial activity toward gram-positive and gram-negative bacteria. Cytotoxicity assay showed that the hydrogels have good biocompatibility. Interestingly, an in-vitro model of wound healing revealed that the nanocomposites allow faster wound closure and repair, compared to the control. Regarding the bone tissue engineering applications, mesenchymal stem cells seeded in the nanocomposite exhibited high bone differentiation which indicate that they could be a good candidate as a potential scaffold for bone tissue regeneration. In another study, we exploited the advantages of local drug delivery by developing a platform with improved efficacy. Having this in mind, we prepared hyaluronic acid-based device containing diclofenac sodium-encapsulated (2-Hydroxypropyl)-β-cyclodextrin (CD) that possess high drug loading along with prolonged release. The platform showed high mechanical properties along with low friction indications high lubricity of the platform. L929 cell morphology and viability assay showed a over the 100 % (approximately 110%) for the injectable device