Thermo-responsive chitosan hydrogel for healing of full-thickness wounds infected with XDR bacteria isolated from burn patients: In vitro and in vivo animal model.

Treatment of non-healing skin wounds infected with extensively drug-resistant (XDR) bacteria remains as a big challenge. To date, different biomaterials have been applied for treatment of post-wound infections, nevertheless their efficacy for treatment of the wounds infected with XDR isolates has not been determined yet. In this study, the potential of the thermo-responsive chitosan (TCTS) hydrogel for protection of full-thickness wounds XDR bacteria isolated from burn patients was evaluated both in vitro and in vivo in a rat model. Antibacterial activity of the TCTS hydrogel against standard strain and clinical isolates of Acinetobacter baumannii, cytobiocompatibility for Hu02 fibroblast cells, degradation rate and swelling ratio were determined in vitro. MTT assay and disk diffusion test indicated no detectable cytotoxicity and antibacterial activity in vitro, respectively. In vivo study showed significant acceleration of wound healing, re-epithelialization, wound closure, and decreased colony count in the TCTS hydrogel group compared with control. This study suggests TCTS hydrogel as an excellent wound dressing for management of the wounds infected with XDR bacteria, and now promises to proceed with clinical investigations.

Conjugation of quantum dots on carbon nanotubes for medical diagnosis and treatment.

Cancer is one of the leading causes of death worldwide and early detection provides the best possible prognosis for cancer patients. Nanotechnology is the branch of engineering that deals with the manipulation of individual atoms and molecules. This area of science has the potential to help identify cancerous cells and to destroy them by various methods such as drug delivery or thermal treatment of cancer. Carbon nanotubes (CNT) and quantum dots (QDs) are the two nanoparticles, which have received considerable interest in view of their application for diagnosis and treatment of cancer. Fluorescent nanoparticles known as QDs are gaining momentum as imaging molecules with life science and clinical applications. Clinically they can be used for localization of cancer cells due to their nano size and ability to penetrate individual cancer cells and high-resolution imaging derived from their narrow emission bands compared with organic dyes. CNTs are of interest to the medical community due to their unique properties such as the ability to deliver drugs to a site of action or convert optical energy into thermal energy. By attaching antibodies that bind specifically to tumor cells, CNTs can navigate to malignant tumors. Once at the tumor site, the CNTs enter into the cancer cells by penetration or endocytosis, allowing drug release, and resulting in specific cancer cell death. Alternatively, CNTs can be exposed to near-infrared light in order to thermally destroy the cancer cells. The amphiphilic nature of CNTs allows them to penetrate the cell membrane and their large surface area (in the order of 2600 m(2)/g) allows drugs to be loaded into the tube and released once inside the cancer cell. Many research laboratories, including our own, are investigating the conjugation of QDs to CNTs to allow localization of the cancer cells in the patient, by imaging with QDs, and subsequent cell killing, via drug release or thermal treatment. This is an area of huge interest and future research and therapy will focus on the multimodality of nanoparticles. In this review, we seek to explore the biomedical applications of QDs conjugated to CNTs, with a particular emphasis on their use as therapeutic platforms in oncology.

Application of OctaAmmonium-POSS functionalized single walled carbon nanotubes for thermal treatment of cancer.

INTRODUCTION: Single walled carbon nanotubes (SWCNTs) have distinctive physical and chemical properties. Additionally, innovative properties can be established to match the clinical need by attachment of functional groups to the SWCNT. In this experiment SWCNT was functionalized with OctaAmmonium-POSS. Evidence suggests that functionalization of SWCNT with OctaAmmonium-POSS would augment the dispersion of SWCNT. We further postulate that functionalization of SWCNT with OctaAmmonium-POSS would enhance the temperature increase of SWCNT upon exposure to NIR laser irradiation. METHODS: Functionalization of SWCNT was conferred by refluxing with acid and OctaAmmonium-POSS. Fourier Transform Infrared (FTIR) test UV-visible spectroscopy and morphology analysis using Transmission Electron Microscopy (TEM) confirmed successful functionalization of SWCNT. NIR irradiation of samples was conducted using an 808 nm laser at 1 watt. Temperature changes were documented using a thermal camera. A HT-29 colorectal cancer cell line was used as a model for photothermal ablation. Cell viability test was performed using trypan blue and fluorescence activated cell sorting (FACS) technique. Graph plotting and statistical analysis was conducted using Graph Pad Prism. RESULTS: Following the functionalization process, TEM images showed a layer on the surface of the SWCNT. In the FTIR experiment, results illustrated the presence of the -COOH group on the functionalized SWCNTs. Upon further functionalization of SWCNT with OctaAmmonium-POSS, various peaks determined the formation of amide bond between the POSS molecule and functionalized SWCNT. The UV-visible spectra also determine the successful functionalization of the SWCNT following its treatment with acid and OctaAmmonium-POSS. Upon exposure to NIR, OctaAmmonium-POSS-SWCNT was the only treatment group that illustrated significantly higher temperature increase than the other treatment groups. Additionally cell death of NIR irradiated OctaAmmonium-POSS-SWCNT was statistically significant compared to other treatment groups. CONCLUSION: OctaAmmonium-POSS was used to render SWCNT biocompatible and water dispersible. Observation from this study determines that functionalization with OctaAmmonium-POSS show greater temperature increase compared to pristine SWCNTs upon its exposure NIR. This significant temperature increase is due to increasing the solubility of SWCNT following its functionalization with OctaAmmonium-POSS.

A new era of cancer treatment: carbon nanotubes as drug delivery tools.

Cancer is a generic term that encompasses a group of diseases characterized by an uncontrolled proliferation of cells. There are over 200 different types of cancer, each of which gains its nomenclature according to the type of tissue the cell originates in. Many patients who succumb to cancer do not die as a result of the primary tumor, but because of the systemic effects of metastases on other regions away from the original site. One of the aims of cancer therapy is to prevent the metastatic process as early as possible. There are currently many therapies in clinical use, and recent advances in biotechnology lend credence to the potential of nanotechnology in the fight against cancer. Nanomaterials such as carbon nanotubes (CNTs), quantum dots, and dendrimers have unique properties that can be exploited for diagnostic purposes, thermal ablation, and drug delivery in cancer. CNTs are tubular materials with nanometer-sized diameters and axial symmetry, giving them unique properties that can be exploited in the diagnosis and treatment of cancer. In addition, CNTs have the potential to deliver drugs directly to targeted cells and tissues. Alongside the rapid advances in the development of nanotechnology-based materials, elucidating the toxicity of nanoparticles is also imperative. Hence, in this review, we seek to explore the biomedical applications of CNTs, with particular emphasis on their use as therapeutic platforms in oncology.