M. Vibin

Laser immunotherapy with gold nanorods causes selective killing of tumour cells

Therapeutic approaches that exploit nanoparticles to deliver drugs selectively to cancer cells are currently considered one of the most promising avenues in the area of cancer therapeutics. Recently, gold nanorods (AuNRs) have shown promising biological applications due to their unique electronic and optical properties. In this paper, we have demonstrated the anti-cancer potential of gold nanorods with low power laser light. Gold nanorods (AuNRs), surface modified with poly (styrene sulfonate) PSS and functionalized with epidermal growth factor receptor antibody conjugated with gold nanorods (anti-EGFR-AuNRs) were successfully synthesised and characterized by UV-Visible-NIR spectrophotometry and High Resolution Transmission Electron Microscopy (HR-TEM). Inductively Coupled Plasmon Atomic Emission Spectrometry (ICP-AES) and Immunofluorescence studies confirmed the efficient uptake of these functionalized gold nanorods by human squamous carcinoma cells, A431. The in vitro photothermal therapy was conducted in four groups - control, laser alone, unconjugated AuNRs with laser and anti-EGFR conjugated AuNRs with laser. Phase contrast images have revealed cell morphology changes and cell death after the laser irradiation. In order to determine whether the cell death occur due to apoptosis or necrosis, we have evaluated the biochemical parameters such as lactate dehydrogenase release, reactive oxygen species level, mitochondrial membrane potential and caspase-3 activity. Flow cytometry analysis have shown the cell cycle changes after laser irradiation with antibody conjugated gold nanorods. Thus the results of our experiments confirmed that immunolabeled gold nanorods can selectively destruct the cancer cells and induce its apoptosis through ROS mediated mitochondrial pathway under low power laser exposure.

Selective photothermal efficiency of citrate capped gold nanoparticles for destruction of cancer cells.

Gold nanoparticles are recently having much attention because of their increased applications in biomedical fields. In this paper, we demonstrated the photothermal efficacy of citrate capped gold nanoparticles (AuNPs) for the destruction of A431 cancer cells. Citrate capped AuNPs were synthesized successfully and characterized by UV-visible-NIR spectrophotometry and High Resolution Transmission Electron Microscopy (HR-TEM). Further, AuNPs were conjugated with epidermal growth factor receptor antibody (anti-EGFR) and applied for the selective photothermal therapy (PTT) of human epithelial cancer cells, A431. PTT experiments were conducted in four groups, Group I--control cells, Group II--cells treated with laser light alone, Group III--cells treated with unconjugated AuNP and further laser irradiation and Group IV--anti-EGFR conjugated AuNP treated cells irradiated by laser light. After laser irradiation, cell morphology changes that were examined using phase contrast microscopy along with the relevant biochemical parameters like lactate dehydrogenase activity, reactive oxygen species generation and caspase-3 activity were studied for all the groups to determine whether cell death occurs due to necrosis or apoptosis. From these results we concluded that, these immunotargeted nanoparticles could selectively induce cell death via ROS mediated apoptosis when cells were exposed to a low power laser light.

Effective cellular internalization of silica-coated CdSe quantum dots for high contrast cancer imaging and labelling applications

The possibility of developing novel contrast imaging agents for cancer cellular labelling and fluorescence imaging applications were explored using silica-coated cadmium selenide (CdSe) quantum dots (QDs). The time dependent cellular internalization efficiency study was carried out using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and Confocal Laser Scanning Microscopy (cLSM) after exposing QDs to stem cells and cancer cells. The strong fluorescence from the cytoplasm confirmed that the QDs were efficiently internalized by the cells. The internalization maxima were observed at the fourth hour of incubation in both stem and cancer cells. Further, the in vitro fluorescence imaging as well as localization study of QDs were performed in various cells. Moreover, high contrast in vivo tumor imaging efficiency of silica-coated CdSe QDs was performed in ultrathin sections of tumor mice, and the results confirmed its effective role in cellular imaging and labelling in cancer and other diseases.

Broccoli Regulates Protein Alterations and Cataractogenesis in Selenite Models

Purpose: To study the efficacy of Brassica oleracea var. italica (Broccoli) in the prevention of selenite induced biochemical changes and the incidence of cataractogenesis in vivo. Methods: Eight day old Sprague-Dawley rat pups were divided into four groups: I—Control; II—Sodium selenite (4 mg/kg body weight) administered; III—Sodium selenite + quercetin; and IV—Sodium selenite + flavonoid fraction of broccoli (FFB). Treatment groups III and IV received quercetin and FFB intraperitoneally from 8th to 15th day at a concentration (2.0 mg/kg body weight). The development of cataract was assessed and graded by slit-lamp examination. Some relevant biochemical parameters—such as activities of superoxide dismutase (SOD), catalase, Ca2+ATPase, calpains, concentration of reduced glutathione (GSH), levels of calcium, lipid peroxidation product—thiobarbituric acid reacting substances (TBARS) and SDS-PAGE analysis of lens water soluble proteins (WSF) were analyzed. Results: FFB modulates selenite-induced biochemical changes in albino rats. Lenses of Group I rats were clear but in Group II, all lenses developed dense opacification (grade 5 and 6), whereas mild opacifications were observed in Group III and Group IV (grade 2). Group III and Group IV lenses exhibited significantly higher values of antioxidant enzymes, Ca2+ATPase, and GSH, whereas lower values were obtained for TBARS, calcium, and calpains compared to Group II. Lens protein profile of water soluble proteins showed normal levels of Group III and Group IV compared to Group II lenses. Conclusion: FFB prevents selenite-induced cataractogenesis in albino rat pups, possibly by maintaining antioxidant status and ionic balance through Ca2+ ATPase pump, inhibition of lipid peroxidation, calpain activation, and protein insolubilization, which have been reported in this article for the first time.

Cellular uptake and subcellular localization of highly luminescent silica-coated CdSe quantum dots – In vitro and in vivo

With excellent optical properties, quantum dots (QDs) have been made as attractive molecular probes for labeling cells in biological research. The purpose of the present work is to explore the possible role of silica-coated cadmium selenide (CdSe) QDs in the in vitro and in vivo cellular uptake and their subcellular localization. The in vitro uptake characteristics of silica-coated CdSe QDs were performed in cultured New Zealand rabbit adipose tissue-derived mesenchymal stem cells (RADMSCs) and Human cervical cancer cells (HeLa) using fluorescence microscopy after staining with 4,6-diamidino-2-phenylindole (DAPI). The in vitro results showed that the silica-coated CdSe QDs were efficiently taken up by the cells and it was localized in the intracellular vesicles giving strong fluorescence from the cytoplasm and nearby nucleus. Subsequently, the in vivo localization and distribution of QDs were studied by the hematoxilin stained semithin cryosections of tissues (~15 μm thickness) under fluorescence microscopy and ultrathin sections of tissues (~100 nm thickness) under confocal laser scanning microscopy at the distribution maxima. Our in vivo results confirmed the effective cellular uptake and even distribution pattern of QDs in tissues. Overall, these in vitro and in vivo results are represented with focus on internalization, subcellular localization and distribution of the QDs, in view of their potential applications in biomedical field.

Embelin (2,5-dihydroxy-3-undecyl-p-benzoquinone): A bioactive molecule isolated from Embelia ribes as an effective photodynamic therapeutic candidate against tumor in vivo

The present study was carried out to assess the photosensitizing potential of embelin, the biologically active natural product isolated from Embelia ribes in photodynamic therapy (PDT) experiments in vivo. In vitro PDT clearly indicated that embelin recorded significant cytotoxicity in Ehrlichs Ascites Carcinoma (EAC) cells, which is superior to 5-aminolevulinic acid, a known photodynamic compound. For in vivo experiments solid tumor was induced using EAC cells in the male Swiss albino mice of groups I, II, III and IV. Group I served as the control (without solid tumor), group II served as tumor bearing mice without treatment and groups III and IV served as treatments. At the completion of 4 weeks of induction, the tumor bearing mice from group III and IV were given an intraperitoneal injection with embelin (12.5mg/kg body weight). After 24h, tumor area in the Group III and IV animals was exposed to visible light from a 1,000 W halogen lamp. The mice from groups I to III were sacrificed 2 weeks after the PDT treatment and the marker enzymes (myeloperoxidase [MPO], β-d-glucuronidase, and rhodanese) were assayed and expression of Bcl-2 and Bax were analyzed in normal and tumor tissues. Animals from group IV were sacrificed after 90 days of PDT treatment and the above mentioned parameters were recorded. Reduction in tumor volume and reversal of biochemical markers to near normal levels were observed in the treated groups. This is the first report on PDT using a natural compound for solid tumor control in vivo. The uniqueness of the mode of treatment lies in the selective uptake of the nontoxic natural compound, embelin from the medicinal plant E. ribes used in Indian system of medicine, by the solid tumor cells and their selective destruction using PDT without affecting the neighboring normal cells, which is much advantageous over radiation therapy now frequently used.

Fluorescence Imaging of Stem Cells, Cancer Cells and Semi-Thin Sections of Tissues using Silica-Coated CdSe Quantum Dots

Trioctylphosphine oxide capped cadmium selenide quantum dots, synthesized in organic media were rendered water soluble by silica overcoating. Silanisation was done by a simple reverse microemulsion method using aminopropyl silane as the silica precursor. Further, the strong photoluminescence of the silica-coated CdSe quantum dots has been utilized to visualize rabbit adipose tissue-derived mesenchymal stem cells (RADMSCs) and Daltons lymphoma ascites (DLA) cancerous cells in vitro. Subsequently the in vivo fluorescence behaviours of QDs in the tissues were also demonstrated by intravenous administration of the QDs in Swiss albino mice. The fluorescence microscopic images in the stem cells, cancer cells and semi-thin sections of mice organs proved the strong luminescence property of silica-coated quantum dots under biological systems. These results establish silica-coated CdSe QDs as extremely useful tools for molecular imaging and cell tracking to study the cell division and metastasis of cancer and other diseases.

Synthesis, characterisation and biocompatibility of surface-functionalised gold nanoparticles

Understanding and controlling the interactions between nanoparticles and living cells are of great importance in the diagnosis and therapeutic applications of nanosized materials. This article describes the synthesis, characterisation and interactions of gold nanoparticles (AuNPs) with different in vitro and in vivo experimental models. Preliminary cytotoxicity studies were carried out in tumour ascites (Daltons lymphoma ascites and Ehrlichs ascites carcinoma) and normal peritoneal cells for different concentrations and it was found that AuNPs did not cause any cell death or morphological changes even at 100 µM concentrations. The tissue distribution and toxicity of intravenously administered AuNPs were investigated in mice because of the fundamental importance of obtaining information about the localisation and biocompatibility of this material. Tissue distribution of AuNPs was studied in normal as well as skin tumour-induced Swiss albino mice using inductively coupled plasma-atomic emission spectrophotometer and transmission electron microscopy. Acute cytotoxicity and histopathology were carried out for toxicity evaluation in AuNP-injected normal mice and found that AuNPs did not cause any significant metabolic change. The health and behaviour of animals were normal throughout the study. The biocompatibility assessment of AuNPs both in vitro and in vivo confirmed that triethylene glycol-functionalised AuNPs are compatible to the biological system and can be used as a safe material for various biological applications.