Xiaolin Nan | Oregon Health & Science University (original) (raw)

Papers by Xiaolin Nan

ChemPhysChem, Mar 27, 2008

ChemBioChem, Oct 27, 2006

Journal of Physical Chemistry B, Dec 1, 2005

bioRxiv (Cold Spring Harbor Laboratory), Feb 27, 2020

Biomolecules, Jul 26, 2022

Small, Oct 21, 2022

Highly branched gold (Au) nanostructures with sharp tips are considered excellent substrates for ... more Highly branched gold (Au) nanostructures with sharp tips are considered excellent substrates for surface‐enhanced Raman scattering (SERS)‐based sensing technologies. Here, a simple synthetic route for producing Au or Au‐Ag bimetallic mesostructures with multiple sharpened tips in the presence of carbon quantum dots (CQDs) is presented. The morphologies of these mesostructured plasmonic nanoparticles (MSPNs) can be controlled by adjusting the concentration of CQDs, reaction temperatures, and seed particles. The optimal molar ratio for [HAuCl4]/[CQDs] is found to be ≈25. At this molar ratio, the diameters of MSPNs can be tuned from 80 to 200 nm by changing the reaction temperature from 25 to 80 °C. In addition, it is found that hierarchical MSPNs consisting of multiple Au nanocrystals can be formed over the entire seed particle surface. Finally, the SERS activity of these MSPNs is examined through the detection of rhodamine 6G and methylene blue. Of the different mesostructures, the bimetallic MSPNs have the highest sensitivity with the ability to detect 10−7 m of rhodamine 6G and 10−6 m of methylene blue. The properties of these MSPN particles, made using a novel synthetic process, make them excellent candidates for SERS‐based chemical sensing applications.

these techniques, imaging with chemical selectivity in unstained samples. CARS microscopy is a no... more these techniques, imaging with chemical selectivity in unstained samples. CARS microscopy is a nonlinear imaging technique that produces images of chemical species based on their vibra-tional signatures. The past five years have seen advances in both the understanding of the method's contrast mechanism and the available instrumentation. 1 Conventional laser scanning microscopes can rou-B iologists desire imaging techniques that provide contrast with high sensitivity and selectivity but without altering the sample. Fluorescence mi-croscopy has high sensitivity, but dyes can alter the sample. Phase-contrast and differential-interference-contrast microscopes avoid this problem at the cost of chemical specificity. Coherent anti-Stokes Raman scattering (CARS) microscopy fits CARS Microscopy Lights Up Lipids in Living Cells tinely carry out these imaging experiments with benign excitation powers of 1 to 2 mW and image acquisition rates up to that of video. The technique is shedding light on many emerging and exciting biological applications. Among the chemical species that it has revealed in living cells, 2 lipids provide the best contrast, offering great potential to augment biomedical research in lipid-related diseases such as obesity and atherosclerosis. CARS microscopy relies on the Raman effect. In the spontaneous Raman process, molecules scatter photons, modifying the photon energy with energy quanta that corresponds to the molecules' vibrational modes. Hence, spontaneous Raman LIVE-CELL IMAGING Figure. 1. In Raman scattering processes, incoming light changes frequency according to a vibrational frequency (Ω) of the molecules. Red-and blue-shifted components are termed Stokes and anti-Stokes lines, respectively. In spontaneous Raman (A), thermally driven and random-phased molecular vibrations cause inefficient scattering in all directions. In coherent anti-Stokes Raman scattering (B), two excitation beams at frequencies ω p and ω s form a beating field with frequency ω p Ϫ ω s. When ω p Ϫ ω s matches Ω, the molecular vibrations occur in-phase and efficiently, resulting in a strong directional signal.

Journal of Physical Chemistry B, Mar 30, 2002

Nature Methods, Jan 30, 2013

Chemistry & Biology, 2006

Hepatitis C virus (HCV) is a global health problem and a leading cause of liver disease. Here, we... more Hepatitis C virus (HCV) is a global health problem and a leading cause of liver disease. Here, we demonstrate that the replication of HCV replicon RNA in Huh-7 cells is inhibited by a peroxisome proliferator-activated receptor (PPAR) antagonist, 2-chloro-5-nitro-N-(pyridyl)benzamide (BA). Downregulation of PPARgamma with RNA interference approaches had no effect on HCV replication in Huh-7 cells, whereas PPARalpha downregulation inhibited HCV replication. Fluorescence and coherent anti-Stokes Raman scattering (CARS) microscopy demonstrate a clear buildup of lipids upon treatment with BA. These observations are consistent with the misregulation of lipid metabolism, phospholipid secretion, cholesterol catabolism, and triglyceride clearance events associated with the inhibition of PPARalpha. The inhibition of HCV replication by BA may result from disrupting lipidation of host proteins associated with the HCV replication complex or, more generally, by disrupting the membranous web where HCV replicates.

ChemPhysChem, Oct 18, 2002

Microscopy and Microanalysis, Aug 1, 2019

Journal of Colloid and Interface Science, 2002

ACS Nano, Sep 2, 2021

Fluorophores are powerful tools for interrogating biological systems. Carbon nanotubes (CNTs) hav... more Fluorophores are powerful tools for interrogating biological systems. Carbon nanotubes (CNTs) have long been attractive materials for biological imaging due to their near-infrared excitation and bright, tunable optical properties. The difficulty in synthesizing and functionalizing these materials with precision, however, has hampered progress in this area. Carbon nanohoops, which are macrocyclic CNT substructures, are carbon nanostructures that possess ideal photophysical characteristics of nanomaterials, while maintaining the precise synthesis of small molecules. However, much work remains to advance the nanohoop class of fluorophores as biological imaging agents. Herein, we report an intracellular targeted nanohoop. This fluorescent nanostructure is noncytotoxic at concentrations up to 50 μM, and cellular uptake investigations indicate internalization through endocytic pathways. Additionally, we employ this nanohoop for two-photon fluorescence imaging, demonstrating a high two-photon absorption cross-section (65 GM) and photostability comparable to a commercial probe. This work further motivates continued investigations into carbon nanohoop photophysics and their biological imaging applications.

Advanced Functional Materials, Sep 1, 2018

Cellular and Molecular Bioengineering, Jun 3, 2015

Advanced Functional Materials, Jul 24, 2018

Current protocols, Nov 1, 2022