Research Interest

Wide-field Epi-fluorescence image (top) and STORM image (bottom) of RCH(Reaction centre H protein)-YFP Rba. sphaeroides. Scalebar:1μm.

Spectroscopic and life-time imaging techniques

Instrumentation of Multimodal fluorescence spectral and life-time imaging microscopy. This technique is capable of high-speed high-resolution spectral and time-resolved data acquisition. It was developed to assess the site-specific immobilisation and the preserved functionality of the light-harvesting complexes attached along nanopatterned structures made in different strategies.

Fluorescence spectral imaging results of protein micro/nano-patterns made by (a) Photolithography, (b) Scanning Near-field Photolithography, (c) Interferometric Lithography, (d) Nanoimprinting. Yellow colour indicates YFP, and green colour indicates GFP. Scale bar: 5μm.

Molecular structure and fluorescence spectral imaging results of (a) LH2, (b) RC-LH1 and (c) LHCII complexes attached along the micro/nano-patterns. Scale bar: 5μm.

LHCII nanopattern imaged in the presence (A) and the absence (B) of 0.03% β-DDM with the corresponding intensity profiles (C). The in-situ emission spectra acquired over two different ROI (D) and fluorescence life-time decay curves measured for nanopatterned LHCII complexes (E) and for a complete monolayer of LHCII (F), the instrument response function (IRF) is shown in gray for both measurements.

Solid immersion lens based high resolution microscopy

Instrumentation of solid immersion fluorescence microsocpy.

SIF image of ATTO655 Phalloidin stained Jurkat cell F-actin cytoskeleton (Filopodia≈ 200nm).

Two derivatives:

Instrumentation of solid immersion total internal reflection fluorescence microscopy.

Images of Synechocystis cells expressing PetC3-GFP in (a) bright-field mode, epifluorescence mode in (b) GFP channel, (c) phycocyanin channel, and (d) by merging two channels; in conventional NA TIRF mode with illumination NA of 1.45 in (e) GFP channel, (f) phycocyanin channel, and (g) by merging two channels; and high NA TIRF mode with illumination NA of 2.2 in (h) GFP channel, (i)phycocyanin channel, and (j) by merging two channels. Scale bar: 2 μm.

Instrumentation of structured illumination solid immersion fluorescence microscopy.

Images of a field of 20nm fluorescent beads obtained with (a), (c) SIF and (b), (d) SISIM. Scale bar: 0:5 μm. 3D surface plots of the beads close to each other in the middle of the images are shown in the small insets (area: 1000nm × 1000 nm).

Surface plasmon techniques & Nanophotonics

A thin film grating waveguide can be used to produce TIR illumination, as shown in Fig.1. The grating is used to selectively couple an incident laser into a specific waveguide mode. The waveguide mode from the grating propagates horizontally to the sample and produces an evanescent wave vertically. The evanescent wave has an exponential decay along the vertical direction, which forms a shallow imaging depth, i.e. penetration depth. The penetration depth of the illumination is determined by the refractive index and thickness of the dielectric film, and the period of the grating waveguide.

Biophotonics