Silver nanoprism enhanced fluorescence in YVO4:Eu3+ nanoparticles

Silver nanoprisms of different sizes influence fluorescence enhancement in YVO4:Eu3+ nanoparticles to various degrees under excitation of green light (532 nm). The local field generated by silver nanoprisms and their dimers is simulated through the FDTD method and a direct correlation with fluorescence enhancement is established

Silver Nanoprisms Acting as Multipolar Nanoantennas under a Low-Intensity Infrared Optical Field Exciting Fluorescence from Eu3

A silver nanoprism (Ag NP) generates a near field due to multipolar surface plasmon resonance (SPR) and lightening rod effects and acts as a multipolar nanoantenna. The ability of Ag NPs to create such an effect even under an infrared (IR) optical field far off of resonance from the SPR frequency is demonstrated through finite difference time domain simulations of exact Ag NPs and hybrids. The conclusive experimental proof of such a near field around Ag NPs under low-intensity (1.5 mW) IR (980 nm) light came when it could excite fluorescence from YVO4/Eu3+ nanoparticles that otherwise do not fluoresce under IR. The results open up new vistas for exclusive plasmonic excitation of fluorescence through metal NP hybrids/ensembles

Silver Nanoprisms Acting as Multipolar Nanoantennas under a Low-Intensity Infrared Optical Field Exciting Fluorescence from Eu³⁺

A silver nanoprism (Ag NP) generates a near field due to multipolar surface plasmon resonance (SPR) and lightening rod effects and acts as a multipolar nanoantenna. The ability of Ag NPs to create such an effect even under an infrared (IR) optical field far off of resonance from the SPR frequency is demonstrated through finite difference time domain simulations of exact Ag NPs and hybrids. The conclusive experimental proof of such a near field around Ag NPs under low-intensity (1.5 mW) IR (980 nm) light came when it could excite fluorescence from YVO₄/Eu³⁺ nanoparticles that otherwise do not fluoresce under IR. The results open up new vistas for exclusive plasmonic excitation of fluorescence through metal NP hybrids/ensembles

Raman Spectroscopic Observation of Gradual Polymorphic Transition and Phonon Modes in CuPc Nanorod

A Raman scattering investigation of a single α-CuPc nanorod is demonstrated here within the temperature range 300–770 K. From the typical thermal dispersion of Raman shift and phonon line width of in-plane B_1g mode at 1526 cm^–1, the metastable α polymorph is observed to undergo unambiguous phase transition to thermally stable β phase. The phase transition temperature (456 K) is observed to be significantly lower than that reported for bulk samples. Extensive computation of normal modes associated with both α- and β-CuPc reveal that the “fingerprint” domain across 1300–1600 cm^–1 is particularly sensitive to this polymorphic transition where a silent B_2g mode appears at 1303 cm^–1 in the spectral vicinity of molecular edge vibration sensitive A_g–B_g Davydov doublet

Tumor suppressor protein SMAR1 modulates the roughness of cell surface: combined AFM and SEM study

<p>Abstract</p> <p>Background</p> <p>Imaging tools such as scanning electron microscope (SEM) and atomic force microscope (AFM) can be used to produce high-resolution topographic images of biomedical specimens and hence are well suited for imaging alterations in cell morphology. We have studied the correlation of SMAR1 expression with cell surface smoothness in cell lines as well as in different grades of human breast cancer and mouse tumor sections.</p> <p>Methods</p> <p>We validated knockdown and overexpression of SMAR1 using RT-PCR as well as Western blotting in human embryonic kidney (HEK) 293, human breast cancer (MCF-7) and mouse melanoma (B16F1) cell lines. The samples were then processed for cell surface roughness studies using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The same samples were used for microarray analysis as well. Tumors sections from control and SMAR1 treated mice as well as tissues sections from different grades of human breast cancer on poly L-lysine coated slides were used for AFM and SEM studies.</p> <p>Results</p> <p>Tumor sections from mice injected with melanoma cells showed pronounced surface roughness. In contrast, tumor sections obtained from nude mice that were first injected with melanoma cells followed by repeated injections of SMAR1-P44 peptide, exhibited relatively smoother surface profile. Interestingly, human breast cancer tissue sections that showed reduced SMAR1 expression exhibited increased surface roughness compared to the adjacent normal breast tissue. Our AFM data establishes that treatment of cells with SMAR1-P44 results into increase in cytoskeletal volume that is supported by comparative gene expression data showing an increase in the expression of specific cytoskeletal proteins compared to the control cells. Altogether, these findings indicate that tumor suppressor function of SMAR1 might be exhibited through smoothening of cell surface by regulating expression of cell surface proteins.</p> <p>Conclusion</p> <p>Tumor suppressor protein SMAR1 might be used as a phenotypic differentiation marker between cancerous and non-cancerous cells.</p