Selectively colorimetric detection of cysteine with triangular silver nanoprisms

Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption, but other 19 kinds of natural amino acids could not. Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.

Synthesis of uniform hexagonal Ag nanoprisms with controlled thickness and tunable surface plasmon bands

In this work,we synthesized monodispersed hexagonal Ag nanoprisms in high yields in a system of poly(vinylpyrrolidone)(PVP)in N-methylpyrrolidone(NMP).A blue shift occurred and was strongly dependent on the thickness of the uniform Ag nanoprisms,which had almost the same radial area.When the Ag nanoprisms grew thicker,their in-plane dipole resonance peaks markedly shifted toward shorter wavelengths(i.e.,blue shift).PVP played a critical role of favoring vertical growth of the Ag nanoplates,preventing aggregation,and inducing the formation of Ag hexagonal nanoprisms(HNPs)through the transformation from thin Ag triangular nanoprisms(TNPs).Compared with similar previous research,the present study provides quite uniform Ag hexagonal nanoplates,which makes the blue shift related more solely and distinctly to the thickness of the Ag nanoprisms.The findings of this work provide a new perspective toward understanding the unique optical characteristics of Ag HNPs with different aspect ratios.

Biological Synthesis of Colloidal Gold Nanoprisms Using <i>Penicillium citrinum</i>MTCC9999

This report provides for the first time rapid novel environment friendly cell surface based synthesis of stable gold nanoprisms at room temperature using Penicillium citrinum MTCC9999 biomass. The UV-Visible spectral scan of dispersed gold nanoparticles (GNPs) solution showed absorption maxima at 540 nm due to surface plasma resonance (SPR) of gold nanoparticles. Typical Transmission Electron Microscopic (TEM) images showed that most of them were prism (55%) shaped with a diameter ranging from 20 - 40 nm. These results obtained from TEM correlated well with the data obtained from Dynamic Light Scattering (DLS) experiment. Average zeta potential of GNPs was -20 mV suggesting some biomolecules capped the nanoparticles imparting a net negative charge over it. FTIR analysis also showed that protein molecules were involved in stabilization.

Colloidal Synthesis of Silver Nanoprisms in Aqueous Medium:Influence of Chemical Compounds in UV/Vis Absorption Spectra

In this work we explore the influence of the factors that affect the formation of silver nanoprisms (AgNPs) with distinct size and size distribution as well as the most intense absorption peak shift. Box-Behnken design analysis was applied to optimize the production of silver nanoprism via colloidal synthesis. The analysis of the responses was based on the nanoprisms plasmon peak wavelength related to in-plane dipole (tunable band) at λmax. ≥ 420 nm. The obtained results indicate that Silver ion is the main variable for the tuning of the size and the Localized Surface Plasmon Resonance (LSPR) frequency. By using the Box-Behnken design it was possible to synthesize nanoparticles with a predictable size and to establish a rigorous control of the plasmon frequency at the range of 600 up to 800 nm.

Novel N-doped multichannel carbon nanofiber architecture with porous CoS nanoprisms for high-performance potassium-ion batteries

Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical application.Herein,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance PIBs.The CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat treatment.The porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge process.In addition,numerous pores facilitated the transport of electrons and ions.Accordingly,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).

Gold nanoprisms as a hybrid in vivo cancer theranostic platform for in situ photoacoustic imaging, angiography, and localized hyperthermia

The development of high-resolution nanosized photoacoustic contrast agents is an exciting yet challenging technological advance. Herein, antibody （breast cancer-associated antigen I （Brcaal） monoclonal antibody）- and peptide （RGD）- functionalized gold nanoprisms （AuNprs） were used as a combinatorial methodology for in situ photoacoustic imaging, angiography, and localized hyperthermia using orthotopic and subcutaneous murine gastric carcinoma models. RGD-conjugated PEGylated AuNprs are available for tumor angiography, and Brcaal monodonal antibody-conjugated PEGylated AuNprs are used for targeting and for in situ imaging of gastric carcinoma in orthotopic tumor models. In situ photoacoustic imaging allowed for anatomical and functional imaging at the tumor site. In vivo tumor angiography imaging showed enhancement of the photoacoustic signal in a time-dependent manner. Furthermore, photoacoustic imaging demonstrated that tumor vessels were clearly damaged after localized hyperthermia. This is the first proof-of-concept using two AuNprs probes as highly sensitive contrasts and therapeutic agents for in situ tumor detection and inhibition. These smart antibody/peptide AuNprs can be used as an efficient nanotheranostic platform for in vivo tumor detection with high sensitivity, as well as for tumor targeting therapy which, with a single-dose injection, results in tumor size reduction and increases mice survival after localized hyperthermia treatment.

LyP-1 peptide-functionalized gold nanoprisms for SERRS imaging and tumor growth suppressing by PTT induced-hyperthermia

Gold-based nanomaterials with plasmonic properties exhibit various potentials for biomedical applications. In this work, gold nanoprisms (GNPs) was synthesized and then modified with LyP-1, a tumor-homing peptide, to improve the affinity of the GNPs to tumor cells, thus, to improve the efficacy of tumor-targeted photothermal therapy. The introduction of NIR dye IR780 not only enabled the GNPs-based nanosystem with the surface-enhanced resonant Raman scattering (SERRS) property, but also enhanced the plasmonic photothermal property which delivering therapeutic heating by 660 nm laser irradiation. The obtained GNPs/IR780-LyP-1 presented significantly increased of photothermal conversion in vitro and in vivo, which resulted in enhanced tumor-targeting photothermal therapeutic efficacy after laser irradiation. Hence, the GNPs/IR780-LyP-1 prepared in this study can be served as a Raman-encoded molecular imaging candidate and photothermal therapy agents for future cancer treatment.

Novel hollow Ni0.33Co0.67Se nanoprisms for high capacity lithium storage

In this work,homogeneous Ni0.33Co0.67Se hollow nanoprisms were synthesized successfully in virtue of Kirkendall effect.It is the first time for bimetallic Ni-Co compounds Ni0.33Co0.67Se to be used in lithium-ion batteries (LIBs).Impressively,the Ni0.33Co0.67Se hollow nanoprisms show superior specific capacity (1,575 mAh/g at the current density of 100 mA/g) and outstanding rate performance (850 mAh/g at 2,000 mA/g) as anode material for LIBs.This work proves the potential of bimetallic chalcogenide compounds as high performance anode materials for LIBs.

Selective Aggregation of Silver Nanoprisms Induced by Monohydrogen Phosphate and its Application for Colorimetric Detection of Chromium(Ⅲ) Ions

In this study,we established a simple colorimetric method for visual detection of chromium(Ⅲ)ions using aggregated silver nanoprisms induced by monohydrogen phosphate.The detection strategy had two steps,selective aggregation of silver nanoprisms with monohydrogen phosphate at high temperature,and anti aggregation of silver nanoprisms in the presence of chromium(Ⅲ)ions.In this strategy,significant spectral shift of the localized surface plasmon resonance(LSPR)absorption peak of silver nanoprisms could be visualized with the color changed from yellow to blue.The spectral peak shift of silver nanoprisms in the anti-aggregation process was linear with the concentrations of the added chromium(Ⅲ)ions in the range of 20.0-800.0 nM.Thus,a colorimetric method for chromium(Ⅲ)ions detection was established with the detection limit of 3.6 nM.The experimental results of real water samples indicated that the colorimetric sensor was potential in environmental monitoring.

Multifunctional shape-dependent plasmonic nanoprobe by enzymatic etching of single gold triangular nanoplate

Hydrogen peroxide(H2O2),as a signaling molecule,plays a vital role in a wide variety of signaling transduction processes,aging,and diseases.However,the excessive production of H2O2 causes various diseases.Herein,we develop a novel method for H2O2 detection in live cells via dark-field scattering spectroscopy with gold triangular nanoprisms(AuTNPs)as probes.The corners of AuTNPs would be gradually oxidatively etched by the strong coordination of Br•which is generated by enzymatic reactions in the presence of horseradish peroxidase(HRP),bromide ion and trace hydrogen peroxide.Benefitting from the morphological change,the single AuTNP based plasmonic nanoprobe shows notable blueshifts and scattering color changes which could be real-time monitored under the dark-field microscopy.The peak position in the scattering spectra of individual AuTNP blueshifts linearly with the increase of H2O2 concentration,and exhibits high sensitivity to H2O2 in a large range from 2.5 to 100µM with a low detection limit(LOD)of 0.74µM.Moreover,the experimental results were supported by the simulated results via the finite-difference time-domain(FDTD)method.The nanoprobes have been further used for intracellular H2O2 detection in live cells.Besides,the etching of AuTNP also provides an alternative method to design novel plasmonic logic chips and write-once plasmonic memories.