4 research outputs found
Synthesis and Characterization of Gold Nanoparticles with Plasmon Absorbance Wavelength Tunable from Visible to Near Infrared Region
Magnetic Nanoparticle Mediated Enhancement of Localized Surface Plasmon Resonance for Ultrasensitive Bioanalytical Assay in Human Blood Plasma
We demonstrate that Fe<sub>3</sub>O<sub>4</sub> magnetic
nanoparticle
(MNP) can greatly enhance the localized surface plasmon resonance
(LSPR) of metal nanoparticle. The high refractive index and molecular
weight of the Fe<sub>3</sub>O<sub>4</sub> MNPs make them a powerful
enhancer for plasmonic response to biological binding events, thereby
enabling a significant improvement in the sensitivity, reliability,
dynamic range, and calibration linearity for LSPR assay of small molecules
in a trace amount. Rather than using fluorescence spectroscopy or
magnetic resonance imaging, this study marks the first use of the
label-free LSPR nanosensor for a disease biomarker in physiological
solutions, providing a low cost, clinical-oriented detection. This
facile and ultrasensitive nanosensor with an extremely light, robust,
and low-cost instrument is attractive for miniaturization on a lab-on-a-chip
system to deliver point-of-care medical diagnostics. To further evaluate
the practical application of Fe<sub>3</sub>O<sub>4</sub> MNPs in the
enhancement of LSPR assay, cardiac troponin I (cTnI) for myocardial
infarction diagnosis was used as a model protein to be detected by
a gold nanorod (GNR) bioprobe. MNP-captured cTnI molecules resulted
in spectral responses up to 6-fold higher than direct cTnI adsorption
on the GNR sensor. The detection limit (LOD) was lowered to ca. 30
pM for plasma samples which is 3 orders lower than a comparable study.
To the best of our knowledge, this marks the lowest LOD for a real
plasma protein detection based on label-free LSPR shift without complicated
instrumentation. The observed LSPR sensing enhancement by Fe<sub>3</sub>O<sub>4</sub> MNPs is independent of nonspecific binding