Development of Methylene Blue Embedded Gold Nanorod@Silica
Nanocomposites as Cancer Theranostic Platform
BACKGROUND
OBJECTIVE
MATERIALS
- TEM images of (a) bare GNRs and (b) GNR@SiO2 nanoparticles
- (a) UV-Vis absorption spectra of (i) GNR, (ii) GNR@SiO2 , and (iii) MB-GNR@SiO2.
(c) Calibration curve obtained from (b) UV-Vis Abs. intensity of MB solution at 664nm upon
increasing concentration from 10 to 30 ㎛
- Micro-Raman spectra of MB solid film and MB-GNR@SiO2 solution excited by (a) 514 nm (10 ㎽, dspot = 1 ㎛) and (b) 785 nm (0.05 ㎽, dspot = 1 ㎛). (c) Temperature variation of DMEM, GNR, and MB-GNR@SiO2 solutions upon NIR laser irradiation
RESULTS
- Bright-field images and micro-Raman spectra of (a) control,
(b) MB-GNR@SiO2-transfected single cancer cell, and (c) MB-GNR@SiO2-transfected
agglomerated cancer cells.
The red cross in the bright-field images indicates the NIR laser-activated area
(λ = 785 nm, 0.05 mW, dspot = 1 ㎛)
 - Dark-field image of the MB-GNR@SiO2 nanoparticle-transfected CT-26 cells after incubation for 2 hrs. Bright yellow color
indicates the nanoparticles loaded into the cytoplasmic
membrane of the cancer cells.
- (a) Chemical toxicity of MB-GNR@SiO2 nanoparticles to cancer cells upon increasing
volume (94.8 ㎍Au/mL) after incubation for 2 hrs. MTT assay was accomplished after
washing residual nanoparticles and further incubation for 12 hrs. Cellular viability of
(b) GNR and (c) MB-GNR@SiO2 loaded CT-26 cancer cells upon laser
(λ= 780nm, power density = 1w/cm2) irradiation time
- Double immunofluorescence staining images of (a) control, (b-f) GNR (3.3 ㎍ Au per well), (g) MB (20 μM), and (i- l) MB-GNR@SiO2-treated CT-26 cancer cells
(3.3 ㎍ Au per well) as a function of NIR laser irradiation time
- ROS staining fluouresence images of (a-d) GNR (3.3 ㎍ Au per well),
(e-h) MB-GNR@SiO2 (3.3 ㎍ Au per well), (i-l) 10 μM MB solution,
and (m-p) 20 μM MB solution-treated CT-26 cancer cells.
CONCLUSION
We successfully synthesized MB-GNR@SiO2 nanoparticles, which showed excellent SERS performance, with a Raman enhancement factor above 3.0 × 1010. This SERS enhancement was enough to detect both agglomerated and single cancer cells. In addition, the resulting MB-GNR@SiO2 nanocomposites had a photon-induced dual modality of photothermal and photosensitizing effects for cancer therapy, and thus the cancer-killing efficacy was remarkably enhanced by the present nanocomposites as compared to GNRs or MBR treatment. Especially, we found that the embedded MB molecules in the GNR@SiO2 nanoparticles had both monomers and dimers, even at a low concentration of 8 μM. Consequently, ROS generation was induced from the MB-GNR@SiO2-transfected cancer cells by the type I and type II pathways related to the photoreaction of the MB molecules. Therefore, we believe that the present study provides empirical evidence to substantiate the promising potential of
MB-GNR@SiO2 nanoparticles to significantly advance the field of cancer theranostics.
Antimicrobial Mechanism of ZnO Nanoparticles
under Dark Condition and Enhanced Antibacterial Activity
OBJECTIVE
Previously reported antibacterial mechanism of ZnO :
ROS mediated antimicrobial process
- (1) UNDER DARK CONDITION
 - (2) UNDER UV LIGHT IRRADIATION
MATERIALS
- TEM Images of ZnO nanoparticles(a-c) and their size distributions(d-f).
-
- Nanoplates (NP)
- Nano-assembly (NA)
- Conventional NPs (CN)
 Diameter (nm)
- XRD patterns of ZnO nanoparticles(a), Zeta potential results of ZnO nanoparticles and bacteria(b), PL spectrum of ZnO nanoparticles(c), and schematic illustration of
band-gap diagram for ZnO crystal(d).
RESULTS
- Under Dark Condition
- Colony forming unit (CFU) changing upon increasing ZnO concentration (a, c) and
its double staining fluorescence images (b, d) of live (green) and dead (red) bacteria.
- Dark-field Images(a) and Confocal Images(b) of ZnO nanoparticles treated bacteria.
- the changing CFU upon co-injection of ZnO/Zn(II) and divalent metal ions(a) and
DNA electrophoresis results of ZnO treated Hind III.
- Under UV Light Irradiation
- Colony forming unit (CFU) changing under UV light irradiation(a, c) and Double staining fluorescence images for detection of live (green) and dead (red) bacteria(b, d).
 - In-situ ROS analysis from ZnO treated bacteria by fluorescence microscopy
CONCLUSION
Antimicrobial mechanism of ZnO under dark condition:
- Antibacterial effect was increasing by decreasing size of ZnO nanoparticles
- Reactive oxygen species (ROS) was not induced by ZnO crystals→The ROS is not main factor for antibacterial effect of ZnO.
- ZnO nanoparticles (NPs) were strongly attached on cell wall of bacteria through electrostatic charge interaction → the Zn(II) ions dissolved from ZnO NPs might interrupt metabolism process through protection of Ca(II), Mn(II), and Mg(II) ion channels in the cell wall but it did not influence on the DNA of bacteria.
Antibacterial effect of ZnO under UV light irradiaion:
- Under UV-light, ZnO nanoplates with the large (0001) surface show remarkably enhanced antibacterial effect due to increasing ROS generation as a consequence of increasing oxygen defect sites.
Magneto-Thermal Effect of Integrated Nanocomposites of Mn-Ferrite on Graphene Oxide Nanosheets
BACKGROUND
Penetration depth for magneto-thermal therapy is much longer than that of photo-thermal therapy but concentration of magnetic nanoparticles for magneto-thermia therapy is too high to apply clinical treatment.
OBJECTIVE
PREVIOUS OUR WORKS
(a ~ c) TEM images of gold nanorod (GO), Fe3O4@SiO2 (IO), and GO-IO-GNR nanocomposites.
(d) Temperature variation of 5 different samples upon laser irradiation time
MATERIALS
TEM images of (a) MnFe2O4, (b) graphene Oxide, (c) MnFe2O4 on graphene oxide (MF-GO)
(c) XRD patterns of MnFe2O4 and (d) Raman spectrum of graphite and graphene oxide
RESULTS
- Dark field images of MF, MF-GO, and PEI coated MF-GO nanocomposites transfected
CT-26 cancer cells
 - Cellular viability of MF-GO and temperature variation of different samples upon RF induced magnetic field
CONCLUSION
Successfully synthesis of integrated MnFe2O4 nanoparticles on graphene oxide
Transfection yield of MF-GO nanocomposites was increased by conjugating polyethylene imine (PEI) due to increasing electrostatic interaction
Concentration of magnetic nanoparticles for magneto-thermal therapy could be reduced by integrating method on graphene oxide substrate due to increasing density of magnetic nanoparticles
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