Ag2[Fe(CN)5NO]-Fabricated Hydrophobic Cotton as a Potential Wound Healing Dressing: An In Vivo Approach.

There have been reports of different types of wound dressings for various functions and purposes. Cotton being one of the most widely used wound dressing material due to its non-toxic, biodegradable, and other properties is used for fabrication as well as in the form of scaffolds for faster and effective wound closure. Our research team has already demonstrated the role of silver nitroprusside nanoparticles (SNPNPs) for wound healing and antibacterial activity. In the current study, we have developed cotton fabric impregnated with SNPNPs (SNPCFs) which remain photo inert and displayed long-term antimicrobial activity due to the surface modification with the silver nitroprusside complex. These SNPCFs were characterized by various analytical techniques (XRD, FTIR, UV spectroscopy, TGA, TEM, FESEM, EDAX, ICP-OES). The fabricated cotton dressings with nanoparticles showed an improved water contact angle (113-130°) than that of bare cotton gauze (60°) and exhibited more antibacterial property in case of both Gram-negative bacteria (Klebsiella aerogenes and Escherichia coli) and Gram-positive bacteria (Pseudomonas aeruginosa and Bacillus subtilis) even after several washings. The biocompatible nature of SNPCFs was assessed by in vivo chorioallantoic membrane assay that showed no obstruction in the formation of blood vessels. The SNPCFs exhibited better wound healing activity compared to the bare cotton and AgCFs as observed in the C57BL6/J mouse. The histopathological investigation reveals increase in re-epithelialization and deposition of connective tissue. The macrophage (M2) counts in SNPCF-treated skin tissues were supportive of more wound healing activity than mice treated with cotton fabric impregnated with chemically synthesized silver nanoparticles. Based on biodistribution analysis using ICP-OES, the data illustrated that a significant amount of silver is absorbed in the skin tissues of mice as compared to the blood and kidney. Furthermore, the absence of silver from the vital organs (heart, liver, and kidney) corroborates our hypothesis that the SNPCFs can act excellently in treating wounds when topically applied over skin. Thereafter, all these results highlight a strong possibility that SNPCFs exemplify the potential as a new antimicrobial and wound healing agent in future times.

In vivo targeting of DNA vaccines to dendritic cells using functionalized gold nanoparticles.

The clinical success of dendritic cell (DC)-based genetic immunization remains critically dependent on the availability of effective and safe nano-carriers for targeting antigen-encoded DNA vaccines to DCs, the most potent antigen-presenting cells in the human body in vivo. Recent studies revealed the efficacies of mannose receptor-mediated in vivo DC-targeted genetic immunization by liposomal DNA vaccine carriers containing both mannose-mimicking shikimoyl and transfection enhancing guanidinyl functionalities. However, to date, the efficacies of this approach have not been examined for metal-based nanoparticle DNA vaccine carriers. Herein, we report for the first time, the design, synthesis, physico-chemical characterization and bioactivities of gold nanoparticles covalently functionalized with a thiol ligand containing both shikimoyl and guanidinyl functionalities (Au-SGSH). We show that Au-SGSH nanoparticles can deliver DNA vaccines to mouse DCs under in vivo conditions. Subcutaneous administration of near infrared (NIR) dye-labeled Au-SGSH showed significant accumulation of the NIR dye in the DCs of the nearby lymph nodes compared to that for the non-targeting NIR-labeled Au-GSH nanoconjugate containing only a covalently tethered guanidinyl group, not the shikimoyl-functionality. Under prophylactic settings, in vivo immunization (s.c.) with the Au-SGSH-pCMV-MART1 nanoplex induced a long-lasting (180 days) immune response against murine melanoma. Notably, mannose receptor-mediated in vivo DC-targeted immunization (s.c.) with the Au-SGSH-MART1 nanoplex significantly inhibited established melanoma growth and increased the overall survivability of melanoma-bearing mice under therapeutic settings. The Au-SGSH nanoparticles reported herein have potential use for in vivo DC-targeted genetic immunization against cancer and infectious diseases.

Ag2[Fe(CN)5NO] Nanoparticles Exhibit Antibacterial Activity and Wound Healing Properties.

Therapeutic agents harboring both wound healing and antibacterial activities have much demand in biomedical applications. Development of such candidates with clinically approved materials adds more advantages toward these applications. Recently, silver metal complex nanomaterials have been playing a major role in medical uses especially for antibacterial activity and wound healing. In this report, we designed and synthesized silver nitroprusside complex nanoparticles (abbreviated as AgNNPs) using sodium nitroprusside and silver nitrate (both are FDA approved precursors). The nanoparticles (AgNNPs) were thoroughly characterized by various physicochemical techniques such as XRD, FTIR, TGA, DLS, EDAX, Raman, ICP-OES, HRTEM, and FESEM. The cell viability assay in normal cells (EA.hy 926 cells, NIH 3T3) using MTT reagents and CEA assay (CEA: Chick embryo angiogenesis assay) in fertilized eggs demonstrate the biocompatibility of AgNNPs. These nanoparticles show effective antibacterial activity against both Gram positive and Gram negative bacteria through membrane and DNA damage. Additionally, AgNNPs accelerate the wound healing in C57BL6 mice by altering the macrophages from M1 to M2. Considering the results together, the current study may offer the development of new silver nanocomplex nanomaterials that shows synergistic effect on antibacterial activity and wound healing (2-in-1-system). To the best of our knowledge, this is the first report for the synthesis, characterization, and biomedical applications of silver nitroprusside nanoparticles.

Pro-angiogenic Properties of Terbium Hydroxide Nanorods: Molecular Mechanisms and Therapeutic Applications in Wound Healing.

The process of angiogenesis, involving generation of new blood vessels from the existing ones, is vital for the supply of oxygen and nutrients to various tissues of body system. Angiogenesis is directly associated with several physiological and pathological processes. It is well-established that impairment in angiogenesis process results in various fatal conditions. Recently, few research groups including ours demonstrated therapeutic angiogenesis through nanomedicine approach using metal oxide/hydroxide nanoparticles. However, there is still a thorough necessity for the development of novel, eco-friendly, pro-angiogenic nanomaterials. Hence, in the present study we demonstrate the in vitro and in vivo pro-angiogenic properties of terbium hydroxide nanorods (THNRs) synthesized using an advanced microwave irradiation method, along with the detailed molecular signaling cascade underlying THNRs induced angiogenesis. The in vivo wound healing and nonimmunogenicity of the THNRs have been validated in the mouse models. We thus strongly believe that the present study establishing the pro-angiogenic properties of THNRs will aid in the development of alternative treatment strategies for wound healing along with cardiovascular and ischemic diseases, where angiogenesis is the chief target.

Copper Prussian blue analogue: investigation into multifunctional activities for biomedical applications.

We have designed and developed stable and biocompatible copper analogues of a Prussian blue (PB) nanoparticle based drug delivery system containing doxorubicin that show selective quenching of fluorescence of doxorubicin compared to PB analogues with other metals and inhibition of cancer cell proliferation, suggesting future potential multifunctional applications in biomedical sciences.