Ag@ZnO Nanoparticles Induce Antimicrobial Peptides and Promote Migration and Antibacterial Activity of Keratinocytes

On-demand Opto-Laser activatable nanoSilver ThermoGel for treatment of full-thickness diabetic wound in a mouse model

Patients suffering from diabetes mellitus are prone to develop diabetic wounds that are non-treatable with conventional therapies. Hence, there is an urgent need of hour to develop the therapy that will overcome the lacunas of conventional therapies. This investigation reports the Quality by Design-guided one-pot green synthesis of unique Opto-Laser activatable nanoSilver ThermoGel (OL→nSil-ThermoGel) for hyperthermia-assisted treatment of full-thickness diabetic wounds in mice models. The characterization findings confirmed the formation of spherical-shaped nanometric Opto-Laser activatable nanoSilver (30.75 ± 2.7 nm; ∆T: 37 ± 0.2 °C → 66.2 ± 0.1 °C; at 1.8 W/cm2 NIR laser density). The findings indicated acceptable in vitro cytocompatibility and significant keratinocyte migration (95.04 ± 0.07 %) activity of OL→nSil towards HaCaT cells. The rheological data of OL→nSil hybridized in situ thermoresponsive gel (OL→nSil-ThermoGel) showed the gelling temperature at 32 ± 2 °C. In vivo studies on full-thickness diabetic wounds in a Mouse model showed OL→nSil-ThermoGel accelerated wound closure (94.42 ± 1.03 %) and increased collagen synthesis, angiogenesis, and decreased inflammatory markers. Similarly, immunohistochemistry study showed significant angiogenesis and faster phenotypic switching of fibroblasts to myofibroblasts in OL→nSil-ThermoGel treated diabetic wounds. Histological evaluation revealed a marked rise in keratinocyte migration, organized collagen deposition, and early regeneration of the epithelial layer compared to the diabetic wound control. In conclusion, the OL→nSil-ThermoGel modulates the cytokines, re-epithelialization, protein expression, and growth factors, thereby improving the repair and regeneration of diabetic wounds in mice.

Sustainable and facile fabrication of chitosan-coated silver-doped zinc oxide nanocomposites exploiting Bergera koenigii foliage for enhanced photocatalysis and antibacterial activity

Industrial and academic chemical pollutants such as Eriochrome Black-T (EBT) and murexide dyes are widely used in academic institution as well as industries, when eluted into rivers, delineate the ill effect on human and aquatic life. Herein, green and ecofriendly synthesis of silver doped-Zinc oxide nanoparticles (Ag/ZnO NPs) and chitosan coated Ag/ZnO nanoparticles (CS/Ag/ZnO NPs) using Bergera koenigii extract to solve environmental issues have been reported for the first time. Spherical and agglomerated particles with crystalline flakes like morphology of Ag/ZnO NPs and CS/Ag/ZnO NPs respectively have been ascertained by Scanning electron morphology (SEM) analyses and XRD. XRD analysis revealed the average crystallite size of 42.16 nm and 48.45 nm for Ag/ZnO NPs with 5 % and 10 % Ag concentration respectively, lesser than crystallite size of 47.394 nm and 52.38 nm for CS-5 % Ag/ZnO NC and CS-10 % Ag/ZnO NC respectively. All the synthesized NPs and NC demonstrated remarkable antibacterial potential against both gram +ve and gram -ve bacteria. Additionally, all the materials showed very high time-dependent photocatalytic degradation activity (>98 %) of EBT and murexide in 12 min. Remarkably, all active nano-catalysts exhibit high durability, and displayed recyclability for >8 cycles. In nutshell, chitosan coated nano-catalyst showed drastic improvement in photocatalytic and antibacterial activities.

Metal nanoparticle hybrid hydrogels: the state-of-the-art of combining hard and soft materials to promote wound healing

Wounds represent a grave affliction that profoundly impacts human well-being. Establishing barriers, preventing infections, and providing a conducive microenvironment constitute the crux of wound therapy. Hydrogel, a polymer with an intricate three-dimensional lattice, serves as a potent tool in erecting physical barriers and nurturing an environment conducive to wound healing. This enables effective control over exudation, hemostasis, accelerated wound closure, and diminished scar formation. As a result, hydrogels have gained extensive traction in the realm of wound treatment. Metallic nanoparticle carriers, characterized by their multifaceted responses encompassing acoustics, optics, and electronics, have demonstrated efficacy in wound management. Nevertheless, these carriers encounter challenges associated with swift clearance and nonuniform effectiveness. The hybridization of metallic nanoparticle carriers with hydrogels overcomes the shortcomings inherent in metallic nanoparticle-based wound therapy. This amalgamation not only addresses the limitations but also augments the mechanical robustness of hydrogels. It confers upon them attributes such as environmental responsiveness and multifunctionality, thereby synergizing strengths and compensating for weaknesses. This integration culminates in the precise and intelligent management of wounds. This review encapsulates the structural classifications, design strategies, therapeutic applications, and underlying mechanisms of metal nanoparticle hybrid hydrogels in the context of acute and chronic wound treatment. The discourse delves into the generation of novel or enhanced attributes arising from hybridization and how the current paradigm of wound therapy leverages these attributes. Amidst this continually evolving frontier, the potential of metal nanoparticle hybrid hydrogels to revolutionize wound treatment is underscored.

Remodeling of intestinal epithelium derived extracellular vesicles by nanoparticles and its bioeffect on tumor cell migration

Extracellular vesicles (EVs) are an effective tool to elucidate the bioeffect of nanomedicines. To clarify the interaction between oral nanomedicines and intestinal epithelial cells, and their bioeffects on downstream cells, polystyrene nanoparticles (PS-NPs) with different sizes were used as the model nanomedicines for EVs induction. Caco-2 monolayers were selected as the model of the intestinal epithelium and DLD-1 cells as the colorectal cancer model proximal to the gastrointestinal tract. It is found that compared with small-sized (25, 50, 100 nm) PS-NPs, the large-sized (200 and 500 nm) exhibited higher co-localization with multivesicular bodies and lysosomes, and more significant reduction of lysosomal acidification in Caco-2 cells. Proteomic and western-blotting analysis showed that the EVs remodeled by large-sized PS-NPs exhibited a higher extent of protein expression changes. The in vitro and in vivo signaling pathway detection in DLD-1 cells and DLD-1 cell xenograft nude mice showed that the remodeled EVs by large-sized PS-NPs inhibited the activation of multiple signaling pathways including Notch3, EGF/EGFR, and PI3K/Akt pathways, which resulted in the inhibition of tumor cell migration. These results primarily clarify the regulation mechanisms of nanomedicines-EVs-receptor cells chain. It provides a new perspective for the rational design and bioeffect evaluation of oral drug nanomaterials and sets up the fundamental knowledge for novel tumor therapeutics in the future.

Inorganic nanoparticles in dermopharmaceutical and cosmetic products: Properties, formulation development, toxicity, and regulatory issues

The use of nanotechnology strategies is a current hot topic, and research in this field has been growing significantly in the cosmetics industry. Inorganic nanoparticles stand out in this context for their distinctive physicochemical properties, leading in particular to an increased refractive index and absorption capacity giving them a broad potential for cutaneous applications and making them of special interest in research for dermopharmaceutical and cosmetic purposes. This performance is responsible for its heavy inclusion in the manufacture of skin health products such as sunscreens, lotions, beauty creams, skin ointments, makeup, and others. In particular, their suitable bandgap energy characteristics allow them to be used as photocatalytic semiconductors. They provide excellent UV absorption, commonly known as UV filters, and are responsible for their wide worldwide use in sunscreen formulations without the undesirable white residue after consumer application. In addition, cosmetics based on inorganic nanoparticles have several additional characteristics relevant to formulation development, such as being less expensive compared to other nanomaterials, having greater stability, and ensuring less irritation, itching, and propensity for skin allergies. This review will address in detail the main inorganic nanoparticles used in dermopharmaceutical and cosmetic products, such as titanium dioxide, zinc oxide, silicon dioxide, silver, gold, copper, and aluminum nanoparticles, nanocrystals, and quantum dots, reporting their physicochemical characteristics, but also their additional intrinsic properties that contribute to their use in this type of formulations. Safety issues regarding inorganic nanoparticles, based on toxicity studies, both to humans and the environment, as well as regulatory affairs associated with their use in dermopharmaceuticals and cosmetics, will be addressed.

Effect of Peptides on the Synthesis, Properties and Wound Healing Capacity of Silver Nanoparticles

The aim of this study is the synthesis of novel peptide-silver nanoparticle conjugates with enhanced wound healing capacity. Peptide-silver nanoparticle conjugates were synthesized using myristoyl tetrapeptide 6 (MT6) or copper tripeptide 1 (CuTP1). Peptide-free silver nanoparticles (AgNP) were synthesized using NaBH4 and sodium citrate and were used as control. The addition of the peptides during or after the synthesis of nanoparticles and its impact on the properties of the synthesized peptide-silver nanoparticle conjugates were assessed. The monitoring of the synthesis of nanoparticles was achieved using ultraviolet-visible spectrophotometry (UV-/Vis). The characteristics and colloidal stability of the nanoparticles (size and ζ-potential distribution, morphology, composition and structure) were monitored using dynamic laser scattering (DLS), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and X-ray diffraction (XRD). The wound healing capacity of the peptide-silver nanoparticle conjugates was assessed using scratch test assay on fibroblasts (NIH/3T3). The results indicated that the addition of the peptides during the synthesis of nanoparticles lead to better yield of the reaction and more effective capping while the size distribution and ζ-potential of the conjugates indicated long-term colloidal stability. The MT6-AgNP conjugate exhibited 71.97 ± 4.35% wound closure, which was about 5.48-fold higher (p < 0.05) than the corresponding free MT6. The CuTP1-AgNP conjugate exhibited 62.37 ± 18.33% wound closure that was better by 2.82 fold (p < 0.05) compared to the corresponding free CuTP1. Both peptides led to the synthesis of silver nanoparticle conjugates with enhanced wound healing capacity compared to the respective free peptide or to the peptide-free AgNP (29.53 ± 4.71% wound closure, p < 0.05). Our findings demonstrated that the synthetized peptide-silver nanoparticle conjugates are promising ingredients for wound care formulation.

Development of Ag-ZnO/AgO Nanocomposites Effectives for Leishmania braziliensis Treatment

Tegumentary leishmaniasis (TL) is caused by parasites of the genus Leishmania. Leishmania braziliensis (L.b) is one of the most clinically relevant pathogens that affects the skin and mucosa, causing single or multiple disfiguring and life-threatening injuries. Even so, the few treatment options for patients have significant toxicity, high dropout rates, high cost, and the emergence of resistant strains, which implies the need for studies to promote new and better treatments to combat the disease. Zinc oxide nanocrystals are microbicidal and immunomodulatory agents. Here, we develop new Ag-ZnO/xAgO nanocomposites (NCPs) with three different percentages of silver oxide (AgO) nanocrystals (x = 49%, 65%, and 68%) that could act as an option for tegumentary leishmaniasis treatment. Our findings showed that 65% and 68% of AgO inhibit the extra and intracellular replication of L.b. and present a high selectivity index. Ag-ZnO/65%AgO NCPs modulate activation, expression of surface receptors, and cytokine production by human peripheral blood mononuclear cells toward a proinflammatory phenotype. These results point to new Ag-ZnO/AgO nanocomposites as a promising option for L. braziliensis treatment.

A stable cyclized antimicrobial peptide derived from LL-37 with host immunomodulatory effects and activity against uropathogens

The increasing antibiotic resistance among uropathogenic bacteria warrants alternative therapeutic strategies. We demonstrate the potential of the synthetic peptide CD4-PP, designed by dimerization and backbone cyclization of the shortest antimicrobial region of human cathelicidin, LL-37. CD4-PP is active against clinical and type strains of common uropathogens Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa at concentrations substantially below cellular cytotoxic levels and induced membrane deformation and leakage in E. coli and P. aeruginosa. Furthermore, CD4-PP treatment prevented the formation of new biofilm and dissolved mature biofilm created by E. coli and P. aeruginosa and targeted curli amyloid in E. coli biofilms. In addition, CD4-PP also induced production of LL-37 by uroepithelial cells and increased the expression of tight junction proteins claudin-14 and occludin. During uroepithelial cell infection, CD4-PP significantly reduced uropathogen survival when treatment was given at the start of infection. Low micromolar of CD4-PP treatment initiated after 2 h was successful with all tested species, except P. aeruginosa where CD4-PP was unable to reduce survival, which could be attributed by early biofilm formation. Finally, we demonstrated that urinary catheter pieces coated with saline fluid supplemented with CD4-PP reduced the attachment of E. coli, giving it a potential clinical application.

Nanoparticles of Bioactive Metals/Metal Oxides and Their Nanocomposites with Antibacterial Drugs for Biomedical Applications

The increasing appearance of new strains of microorganisms resistant to the action of existing antibiotics is a modern problem that requires urgent decision. A promising potential solution is the use of nanoparticles of bioactive metals and their oxides as new antibacterial agents, since they are capable of affecting pathogenic microorganisms by mechanisms different from the mechanisms of action of antibiotics. Inorganic nanoparticles possess a wide spectrum of antibacterial activity. These particles can be easily conjugated with drug molecules and become carriers in targeted drug-delivery systems. This paper discusses the benefits and prospects of the application of nanoparticles from metals and metal oxides and their nanocomposites with antibacterial drugs.

Photosensitizer Nanodot Eliciting Immunogenicity for Photo-Immunologic Therapy of Postoperative Methicillin-Resistant Staphylococcus aureus Infection and Secondary Recurrence

The treatment of postoperative infection caused by multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), has become an intractable clinical challenge owing to its low therapeutic efficacy and high risk of recurrence. Apart from imperfect antibacterial therapies, induction of insufficient immunogenicity, required for the successful clearance of a pathogen, may also contribute to the problem. Herein, an ultra-micro photosensitizer, AgB nanodots, using photothermal therapy, photodynamic therapy, and Ag⁺ ion sterilization, are utilized to efficiently clear invading MRSA both in vitro and in vivo. AgB nanodots are also found to upregulate host immunogenicity in a murine model and establish immunological memory by promoting the upregulated expression of danger signals that are commonly induced by stress-related responses, including sudden temperature spikes or excess reactive oxygen production. These stimulations boost the antibacterial effects of macrophages, dendritic cells, T cells, or even memory B cells, which is usually defined as infection-related immunogenic cell death. Hence, the proposed AgB nanodot strategy may offer a novel platform for the effective treatment of postoperative infection while providing a systematic immunotherapeutic strategy to combat persistent infections, thereby markedly reducing the incidence of recurrence following recovery from primary infections.

Nano-biotechnology, an applicable approach for sustainable future

Nanotechnology is one of the most emerging fields of research within recent decades and is based upon the exploitation of nano-sized materials (e.g., nanoparticles, nanotubes, nanomembranes, nanowires, nanofibers and so on) in various operational fields. Nanomaterials have multiple advantages, including high stability, target selectivity, and plasticity. Diverse biotic (e.g., Capsid of viruses and algae) and abiotic (e.g., Carbon, silver, gold and etc.) materials can be utilized in the synthesis process of nanomaterials. "Nanobiotechnology" is the combination of nanotechnology and biotechnology disciplines. Nano-based approaches are developed to improve the traditional biotechnological methods and overcome their limitations, such as the side effects caused by conventional therapies. Several studies have reported that nanobiotechnology has remarkably enhanced the efficiency of various techniques, including drug delivery, water and soil remediation, and enzymatic processes. In this review, techniques that benefit the most from nano-biotechnological approaches, are categorized into four major fields: medical, industrial, agricultural, and environmental.

Antioxidant, anti-inflammatory, and wound healing effects of topical silver-doped zinc oxide and silver oxide nanocomposites

Silver nanoparticles (Ag-NPs), silver oxide nanoparticles (AgO-NPs), and zinc oxide nanoparticles (ZnO-NPs) have healing, antibacterial, and antioxidant properties. Furthermore, Ag-NPs and ZnO-NPs also have anti-inflammatory properties. In this study, we synthesized a nanocomposite using Ag-ZnO and AgO-NPs (Ag-ZnO/AgO NPs). The structural and morphological properties of nanocrystals and nanocomposite were investigated by X-ray diffraction and scanning electronics microscopic. The wurtzite crystalline structure of Ag-ZnO and two morphologies for the nanocomposite (nanorods and nanoplatelets) were determined. Topical treatment with 1% Ag-ZnO/AgO NPs was compared to untreated wounds (control group). Wounds were induced in the dorsal region of BALB/c mice and evaluated after 3, 7, 14, and 21 days of treatment. The nanocomposite demonstrated anti-inflammatory and antioxidant capacities. In addition, wounds treated with Ag-ZnO/AgO NPs showed accelerated closure, non-cytotoxicity, especially on keratinocytes and collagen deposition, and increased metalloproteinases 2 and 9 activity. The nanocomposite improved healing by reducing the inflammatory process, protecting tissues from damage caused by free radicals, and increasing collagen deposition in the extracellular matrix. These characteristics contributed to the accelerated wound closure process. Thus, Ag-ZnO/AgO NPs show potential for can be a strategy for topical use in formulations of new drugs to treat wounds.

Dendritic Hydrogels Induce Immune Modulation in Human Keratinocytes and Effectively Eradicate Bacterial Pathogens

Infections caused by antibiotic-resistant bacteria are globally a major threat, leading to high mortality rates and increased economic burden. Novel treatment strategies are therefore urgently needed by healthcare providers to protect people. Biomaterials that have inherent antibacterial properties and do not require the use of antibiotics present an attractive and feasible avenue to achieve this goal. Herein, we demonstrate the effect of a new class of cationic hydrogels based on amino-functional hyperbranched dendritic-linear-dendritic copolymers (HBDLDs) exhibiting excellent antimicrobial activity toward a wide range of clinical Gram-positive and Gram-negative bacteria, including drug-resistant strains isolated from wounds. Intriguingly, the hydrogels can induce the expression of the antimicrobial peptides RNase 7 and psoriasin, promoting host-mediated bacterial killing in human keratinocytes (HaCaT). Moreover, treatment with the hydrogels decreased the proinflammatory cytokine IL-1β, reactive nitrogen species (NO), and mitochondrial reactive oxygen species (ROS) in S. aureus-infected HaCaT cells, conjunctively resulting in reduced inflammation.