Research
Developing novel SWIR photonic nanomaterials
Single-photon Source from Fluorescent Quantum Defects in Single-walled Carbon Nanotubes
Fluorescent quantum defects in single-walled carbon nanotubes are the only known room-temperature single photon emitters at telecom-wavelengths (or short-wave infrared; 1000-1700 nm). This novel low-dimensional nanomaterial provides promising applications for quantum computing, quantum communications, and biomedical imaging. We are interested in exploring new types of quantum defects and new synthetic methods.
Nanotube Handedness and Its Applications
SWCNTs have left- and right-handed helicities as shown in the Figure on the right. Optical isomers of the nanoparticles, similar to small molecules, have revealed distinct effects to the physiological functions. For example, chiral polymer-coated gold nanoparticles can induce cancer cell autophagocytosis. Thus, it is important to consider that optical isomers of the SWCNTs interact with the chiral environment differently. Indeed, the optical isomers have been successfully separated using chiral ssDNAs. Our lab is interested in studying how specific handedness of the SWCNTs behaves when administered in vivo.
Studying Fundamental Properties of Photonic Nanomaterials
Instrument and methodology development
Developing customized instruments and methodologies enables discovery of novel phenomenon from nanomaterials. For example, the SEFR-SPC is an easier, cheaper and more efficient alternative method to yield distortion-free SWIR kinetic curves at sub-micro second to sub-milli-second scale. This method is ideal for measuring singlet-oxygen emissions and delayed fluorescence from single-walled carbon nanotubes. We are also very interested in developing other novel instruments for time domain and frequency domain measurements.
Photophysical and Photochemical Properties of Photonic Nanomaterials
Studying fundamental properties of photonic nanomaterials helps us understand the materials themselves as well as building novel applications based on the observations. Singlet oxygen is known to be one of the components of reactive oxygen species (ROS), which is produced in cells upon oxidative stress. We discovered that the carbon nanotubes can emit fluorescence sensitized by singlet oxygens.
Building Diagnostic Modalities for Cancers and more
SWIR flow and image cytometries
Cytometry plays a crucial role in characterizing cell properties, but its restricted optical window (400-850 nm) limits the number of stained fluorophores that can be detected simultaneously and hampers the study and utilization of short-wave infrared (SWIR; 900-1,700 nm) fluorophores in cells. Here we introduce two SWIR-based methods to address these limitations: SWIR flow cytometry and SWIR image cytometry. We develop a quantification protocol for deducing cellular fluorophore mass. Both systems achieve a limit of detection of ~0.1 fg cell−1 within a 30-min experimental timeframe, using individualized, high-purity (6,5) single-wall carbon nanotubes as a model fluorophore and macrophage-like RAW264.7 as a model cell line. This high-sensitivity feature reveals that low-dose (6,5) serves as an antioxidant, and cell morphology and oxidative stress dose-dependently correlate with (6,5) uptake. Our SWIR cytometry holds immediate applicability for existing SWIR fluorophores and offers a solution to the issue of spectral overlapping in conventional cytometry.
Real-time in vivo imaging using fluorescent quantum defects as imaging agent
Photons passing through tissues give much lower scattering and autofluorescence when excited at short-wave infrared region. Creating fluorescent quantum defects in carbon nanotubes shifts the emission to even longer wavelengths (>1100 nm). These chemically "doped" nanotubes can be excited at their maximum absorption peak at E11, which was occupied by the emission band in pristine nanotubes. This new E11* band also minimizes reabsorption problem because of its extremely low density. Figure on the left shows clear vascularture and lymphatic structure after intravenous administration of low concentration nanotubes (~100 ng). We are very interested in using fluorescent quantum defects to develop next generation imaging probes for research and clinical applications, especially detecting cancers.
3D Localization of small tumors
Identifying 3D location of interested targets in vivo is important for addressing clinical decision-making such as surgical debulking of tumor burdens. We are interested in using SWIR photonic nanomaterials to target the cancer cells and developing 3D localization methods to find the positions of small tumor burdens. Figure on the right describes spectral triangulation method, which uses spectral information of the emitted photons to deduce the location of the SWCNT source. We will develop novel localization method using time-domain information in the near future.
Developing Bio-degradable Nanomedicine
Newest Research Topics
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Our research projects are supported by
Copyright LinCW Group | Email: linc [at] sinica.edu.tw | Phone: + 886-2-2362-4976 | Address: No. 1, Sec. 4, Roosevelt Rd., Taipei 106319, Taiwan | [中文]