Optical endoscopic imaging, which was recently equipped with bioluminescence, fluorescence, and Raman scattering, allows minimally invasive real-time detection of pathologies on the surface of hollow organs. To characterize pathologic lesions in a multiplexed way, we developed a dual modal fluorescence-Raman endomicroscopic system (FRES), which used fluorescence and surface-enhanced Raman scattering nanoprobes (F-SERS dots). Real-time, in vivo, and multiple target detection of a specific cancer was successful, based on the fast imaging capability of fluorescence signals and the multiplex capability of simultaneously detected SERS signals using an optical fiber bundle for intraoperative endoscopic system. Human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR) on the breast cancer xenografts in a mouse orthotopic model were successfully detected in a multiplexed way, illustrating the potential of FRES as a molecular diagnostic instrument that enables real-time tumor characterization of receptors during routine endoscopic procedures.
Ag-coated Au nanoparticle (NP)-embedded silica nanospheres (SiO2@Au@Ag NSs) were prepared using three different Au NPs of 2.5, 7 and 15 nm diameter to investigate their optical properties.
Antibody-conjugated nanoparticles (NPs) have attracted great attention in diagnostic and therapeutic applications due to their high sensitivity and specificity for biotargets, as well as their wide applicability. Unfortunately, these features are significantly affected by antibody conjugation methods in terms of conjugation efficiency, orientation of the target binding site in the antibody, and denaturation during chemical conjugation reactions. Furthermore, the number of conjugated antibodies on each NP and the overall targeting efficacy are critical factors for a quantitative bioassay with antibody-conjugated NPs. Herein, we report a versatile and oriented antibody conjugation method using copper-free click chemistry. Moreover, the number of conjugated antibodies and their binding capacity were quantitatively and experimentally evaluated using fluorescently-labeled antibodies and antigens. The strong binding capability of antibody-conjugated NPs prepared using the copper-free click chemistry-based conjugation strategy was 8 times superior to the binding capability seen following the use of the EDC/NHS-coupling method. Additionally, the versatility of the developed antibody conjugation method was also demonstrated by conjugation of the antibody to three kinds of silica-encapsulated NPs.
Surface-enhanced
Raman scattering (SERS) spectroscopy is attractive
in various detection analysis fields. However, the quantitative method
using SERS spectroscopy remains as an area to be developed. The key
issues in developing quantitative analysis methods by using SERS spectroscopy
are the fabrication of reliable SERS-active materials such as nanoparticle-based
structures and the acquisition of the SERS signal without any disturbance
that may change the SERS signal intensity and frequency. Here, the
fabrication of seamless multilayered core–shell nanoparticles
with an embedded Raman label compound as an internal standard (MLRLC dots) for quantitative SERS analysis is reported. The embedded
Raman label compound in the nanostructure provides a reference value
for calibrating the SERS signals. By using the MLRLC dots,
it is possible to gain target analyte signals of different concentrations
while retaining the Raman signal of the internal standard. The ML4‑BBT dots, containing 4-bromobenzenethiol (4-BBT) as
an internal standard, are successfully applied in the quantitative
analysis of 4-fluorobenzenethiol and thiram, a model pesticide. Additionally,
ratiometric analysis was proved practical through normalization of
the relative SERS intensity. The ratiometric strategy could be applied
to various SERS substrates for quantitative detection of a wide variety
of targets.
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