BIOCONJUGATED QUANTUM DOTS BASED RAPID DETECTION OF PATHOGENIC BACTERIA FROM WATER SAMPLES

2011 ◽  
Vol 10 (01n02) ◽  
pp. 199-203 ◽  
Author(s):  
RICHA JACKERAY ◽  
GURPAL SINGH ◽  
SWATI JAIN ◽  
ZAINUL ABID CKV ◽  
HARPAL SINGH ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Salmonella Typhi ◽  
Laser Scanning Microscopy ◽  
Fluorescent Label ◽  
Confocal Laser ◽  
Enzyme Linked Immunosorbent Assay ◽  
Core Shell ◽  
Exchange Method

A sensitive and rapid method for the detection of pathogenic bacteria (Salmonella typhi) in water sample was developed using core-shell CdSe / ZnS quantum dots (QDs) as fluorescence label. Surface-functionalized core-shell quantum dots were synthesized by successive ion layer adsorption and reaction (SILAR) technique and were made hydrophilic by ligand exchange method. Developed hydrophobic and hydrophilic QDs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and spectrofluorimetry. Carboxy- terminated QDs were conjugated with bacteria-specific antibodies (S. typhi-specific IgG) for the preparation of photostable fluorescent label and were characterized by various techniques like spectrofluorimetry and enzyme-linked immunosorbent assay (ELISA) for their photoluminescence and successful bioconjugation. Antibody (Ab)-conjugated QDs were incubated with bacteria-contaminated water for S. typhi detection. Microscopic images and spectral profile of bacteria–Ab conjugated QDs complex were recorded by confocal laser scanning microscopy (CLSM). A sensitivity of 103 organisms/mL of targeted bacteria (S. typhi) could be attained in a period of about 2 h.

scholarly journals Specific Intracellular Uptake of Herceptin-Conjugated CdSe/ZnS Quantum Dots into Breast Cancer Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Seung-Jin Han ◽  
Pierson Rathinaraj ◽  
Soo-Young Park ◽  
Young Kyoo Kim ◽  
Joon Hyung Lee ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Quantum Dots ◽  
Cell Death ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Laser Scanning ◽  
Specific Binding ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Core Shell

Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs) to enhance their specific interactions with breast cancer cells (SK-BR3). The mean size of the core-shell quantum dots (28 nm), as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. Thein vitrocell culture experiment showed that the keratin forming cancer cells (KB) proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL), whereas most of the breast cancer cells (SK-BR3) had died. To clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined by confocal laser scanning microscopy. As a result, the QD-Her bound specifically to the membrane of SK-BR3, which became almost saturated after 6 hours incubation. This suggests that the growth signal of breast cancer cells is inhibited completely by the specific binding of herceptin to the Her-2 receptor of SK-BR3 membrane, resulting in cell death.

scholarly journals One-step preparation of antimicrobial silicone materials based on PDMS and salicylic acid: insights from spatially and temporally resolved techniques

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Luca Barbieri ◽  
Ioritz Sorzabal Bellido ◽  
Alison J. Beckett ◽  
Ian A. Prior ◽  
Jo Fothergill ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Pharmaceutical Products ◽  
Laser Scanning Microscopy ◽  
Wound Dressings ◽  
Confocal Laser ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
One Step

AbstractIn this work, we introduce a one-step strategy that is suitable for continuous flow manufacturing of antimicrobial PDMS materials. The process is based on the intrinsic capacity of PDMS to react to certain organic solvents, which enables the incorporation of antimicrobial actives such as salicylic acid (SA), which has been approved for use in humans within pharmaceutical products. By combining different spectroscopic and imaging techniques, we show that the surface properties of PDMS remain unaffected while high doses of the SA are loaded inside the PDMS matrix. The SA can be subsequently released under physiological conditions, delivering a strong antibacterial activity. Furthermore, encapsulation of SA inside the PDMS matrix ensured a diffusion-controlled release that was tracked by spatially resolved Raman spectroscopy, Attenuated Total Reflectance IR (ATR-IR), and UV-Vis spectroscopy. The biological activity of the new material was evaluated directly at the surface and in the planktonic state against model pathogenic bacteria, combining confocal laser scanning microscopy, electron microscopy, and cell viability assays. The results showed complete planktonic inhibition for clinically relevant strains of Staphylococcus aureus and Escherichia coli, and a reduction of up to 4 orders of magnitude for viable sessile cells, demonstrating the efficacy of these surfaces in preventing the initial stages of biofilm formation. Our approach adds a new option to existing strategies for the antimicrobial functionalisation of a wide range of products such as catheters, wound dressings and in-dwelling medical devices based on PDMS.

scholarly journals Intracellular Localization of Interleukin-6 in Eosinophils From Atopic Asthmatics and Effects of Interferon γ

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2508-2516 ◽  
Author(s):  
Paige Lacy ◽  
Francesca Levi-Schaffer ◽  
Salahaddin Mahmudi-Azer ◽  
Ben Bablitz ◽  
Stacey C. Hagen ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Laser Scanning ◽  
Intracellular Localization ◽  
Interferon Γ ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dot Blot ◽  
Human Eosinophil ◽  
Arylsulfatase B

Abstract Eosinophils, prominent cells in asthmatic inflammation, have been shown to synthesize, store, and release an array of up to 18 cytokines and growth factors, including interleukin-6 (IL-6). In this report, we show that IL-6 immunofluorescence localizes to the matrix of the crystalloid granule in peripheral blood eosinophils from atopic asthmatics using confocal laser scanning microscopy (CLSM). Granule localization of IL-6 was confirmed using dot-blot analysis and enzyme-linked immunosorbent assay (ELISA) on subcellular fractions of highly purified eosinophils produced from density centrifugation across a 0% to 45% Nycodenz gradient. IL-6 was found to coelute with eosinophil crystalloid granule marker proteins, including eosinophil peroxidase (EPO), major basic protein (MBP), arylsulfatase B, and β-hexosaminidase. Immunoreactivity to IL-6 colocalized with granule-associated IL-2 and IL-5 in subfractionated eosinophils. We also made the novel and compelling observation that interferon γ (IFNγ), a Th1-type cytokine, stimulated an early elevation in eosinophil IL-6 immunoreactivity. A 2.5-fold enhancement of IL-6 immunoreactivity in eosinophil granules was observed within 10 minutes of IFNγ treatment (500 U/mL), as determined by subcellular fractionation and CLSM. These findings suggest that IFNγ has short-term effects on human eosinophil function and imply that a physiologic role exists for Th1-type cytokine modulation of Th2-type responses in these cells.

scholarly journals High In Vitro Antibacterial Activity of Pac-525 againstPorphyromonas gingivalisBiofilms Cultured on Titanium

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-yin Li ◽  
Xue-jin Wang ◽  
Li-na Wang ◽  
Xiao-xia Ying ◽  
Xiang Ren ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Fusobacterium Nucleatum ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Average Cell ◽  
Biofilm Thickness ◽  
Live Bacteria ◽  
In Vitro Antibacterial Activity

In order to investigate the potential of short antimicrobial peptides (AMPs) as alternative antibacterial agents during the treatment of peri-implantitis, the cytotoxic activity of three short AMPs, that is, Pac-525, KSL-W, and KSL, was determined using the MTT assay. The antimicrobial activity of these AMPs, ranging in concentration from 0.0039 mg/mL to 0.5 mg/mL, against the predominant planktonic pathogens, includingStreptococcus sanguis, Fusobacterium nucleatum, andPorphyromonas gingivalis, involved in peri-implantitis was investigated. Furthermore, 2-day-oldP. gingivalisbiofilms cultured on titanium surfaces were treated with Pac-525 and subsequently observed and analysed using confocal laser scanning microscopy (CLSM). The average cell proliferation curve indicated that there was no cytotoxicity due to the three short AMPs. The minimum inhibitory concentration and minimum bactericidal concentration values of Pac-525 were 0.0625 mg/mL and 0.125 mg/mL, respectively, forP. gingivalisand 0.0078 mg/mL and 0.0156 mg/mL, respectively, forF. nucleatum. Using CLSM, we confirmed that compared to 0.1% chlorhexidine, 0.5 mg/mL of Pac-525 caused a significant decrease in biofilm thickness and a decline in the percentage of live bacteria. These data indicate that Pac-525 has unique properties that might make it suitable for the inhibition the growth of pathogenic bacteria around dental implants.

scholarly journals Quantifying Cytosolic Cytochrome c Concentration Using Carbon Quantum Dots as a Powerful Method for Apoptosis Detection

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1556
Author(s):  
Cristian Silviu Moldovan ◽  
Anca Onaciu ◽  
Valentin Toma ◽  
Radu Marginean ◽  
Alin Moldovan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cytochrome C ◽  
Laser Scanning ◽  
A549 Cells ◽  
Carbon Quantum Dots ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Fluorescent Nanoparticles ◽  
Cyt C

Background: Cytochrome c (Cyt c) is a key biomarker for early apoptosis, and many methods were designed to detect its release from mitochondria. For a proper evaluation of these programed cell death mechanisms, fluorescent nanoparticles are excellent candidates due to their valuable optical properties. Among all classes of nanoparticles developed thus far, carbon-based quantum dots bring qualitative and efficient imaging strategies for biomedical applications as a consequence of their biocompatibility and low cytotoxicity. Methods: In this study, we synthesized carbon quantum dots smaller than 5 nm from sodium citrate and polyethylene imine. These nanoparticles were rigorously characterized, and their quenching capacity in apoptotic events was assessed in A549 cells treated with staurosporine and etoposide. For the evaluation of Cyt c release, a phenomenon directly correlated with apoptotic events, we ran a semiquantitative analysis using confocal laser scanning microscopy. Results: Carbon quantum dots were synthesized and were successfully employed for Cyt c detection by means of fluorescence microscopy. Significant drops in fluorescence intensity were observed in the case of cells treated with apoptosis-inducing therapeutic compounds compared to untreated cells, confirming Cyt c release from mitochondria to cytosol. Conclusion: Considering these results, we strongly believe this method can contribute to an indirect in vitro evaluation of apoptosis.

scholarly journals Intracellular Localization of Interleukin-6 in Eosinophils From Atopic Asthmatics and Effects of Interferon γ

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2508-2516
Author(s):  
Paige Lacy ◽  
Francesca Levi-Schaffer ◽  
Salahaddin Mahmudi-Azer ◽  
Ben Bablitz ◽  
Stacey C. Hagen ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Laser Scanning ◽  
Intracellular Localization ◽  
Interferon Γ ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dot Blot ◽  
Human Eosinophil ◽  
Arylsulfatase B

Eosinophils, prominent cells in asthmatic inflammation, have been shown to synthesize, store, and release an array of up to 18 cytokines and growth factors, including interleukin-6 (IL-6). In this report, we show that IL-6 immunofluorescence localizes to the matrix of the crystalloid granule in peripheral blood eosinophils from atopic asthmatics using confocal laser scanning microscopy (CLSM). Granule localization of IL-6 was confirmed using dot-blot analysis and enzyme-linked immunosorbent assay (ELISA) on subcellular fractions of highly purified eosinophils produced from density centrifugation across a 0% to 45% Nycodenz gradient. IL-6 was found to coelute with eosinophil crystalloid granule marker proteins, including eosinophil peroxidase (EPO), major basic protein (MBP), arylsulfatase B, and β-hexosaminidase. Immunoreactivity to IL-6 colocalized with granule-associated IL-2 and IL-5 in subfractionated eosinophils. We also made the novel and compelling observation that interferon γ (IFNγ), a Th1-type cytokine, stimulated an early elevation in eosinophil IL-6 immunoreactivity. A 2.5-fold enhancement of IL-6 immunoreactivity in eosinophil granules was observed within 10 minutes of IFNγ treatment (500 U/mL), as determined by subcellular fractionation and CLSM. These findings suggest that IFNγ has short-term effects on human eosinophil function and imply that a physiologic role exists for Th1-type cytokine modulation of Th2-type responses in these cells.

Sign in / Sign up

Export Citation Format

Share Document