Chun-Chin Wang

Differentiation of normal and cancerous lung tissues by multiphoton imaging

In this work, we utilized multiphoton microscopy for the label-free diagnosis of non-cancerous, lung adenocarcinoma (LAC), and lung squamous cell carcinoma (SCC) tissues from human. Our results show that the combination of second harmonic generation (SHG) and multiphoton excited autofluorescence (MAF) signals may be used to acquire morphological and quantitative information in discriminating cancerous from non-cancerous lung tissues. Specifically, non-cancerous lung tissues are largely fibrotic in structure while cancerous specimens are composed primarily of tumor masses. Quantitative ratiometric analysis using MAF to SHG index (MAFSI or SAAID) shows that the average MAFSI for noncancerous and LAC lung tissue pairs are 0.55 ±0.23 and 0.87±0.15 respectively. In comparison, the MAFSIs for the noncancerous and SCC tissue pairs are 0.50±0.12 and 0.72±0.13 respectively. Intrinsic fluorescence ratio (FAD/NADH) of SCC and non-cancerous tissues are 0.40±0.05 and 0.53±0.05 respectively, the redox ratio of SCC diminishes significantly, indicating that increased cellular metabolic activity. Our study shows that nonlinear optical microscopy can assist in differentiating and diagnosing pulmonary cancer from non-cancerous tissues. With additional development, multiphoton microscopy may be used for the clinical diagnosis of lung cancers.

Enhancement of random lasing through fluorescence resonance energy transfer and light scattering mediated by nanoparticles

A simple approach for the enhancement of random lasing based on fluorescence resonance energy transfer and light scattering mediated by nanoparticles is reported. To illustrate our working principle, ZnO nanorods decorated with TiO2 nanoparticles were chosen as an example. It is shown that the random laser action of ZnO nanorods can be significantly improved by the assistance of TiO2 nanoparticles. Moreover, due to the inherent nature of higher refractive index of TiO2 than ZnO, the TiO2 nanoparticles can serve efficiently as better nanoscatterers, which can promote the formation of closed-loop paths. Our strategy provided here is very useful for the future development of high efficiency optoelectronic devices.

Enhancement of random lasing assisted by light scattering and resonance energy transfer based on ZnO/SnO nanocomposites

A new composite consisting of ZnO nanorods and SnO nanoparticles has been synthesized and characterized. It is found that the UV laser emission from ZnO NRs can be greatly enhanced and more easily achieved by the assistance of SnO NPs. The underlying mechanism is interpreted in terms of light scattering, charge carrier transfer and fluorescence resonance energy transfer (FRET) mediated by SnO NPs. Our strategy opens a promising route for improving the external conversion efficiency of optoelectronic devices.

Label-free discrimination of normal and pulmonary cancer tissues using multiphoton fluorescence ratiometric microscopy

We performed multiphoton excited autofluorescence and second harmonic generationmicroscopy for the distinction of normal, lung adenocarcinoma (LAC), and squamous cell carcinoma (SCC) specimens. In addition to morphological distinction, we derived quantitative metrics of cellular redox ratios for cancer discrimination. Specifically, the redox ratios of paired normal/SCC and normal/LAC specimens were found to be 0.53 ± 0.05 / 0.41 ± 0.06 and 0.56 ± 0.02 / 0.35 ± 0.06 , respectively. The lower redox ratios in cancer specimens, indicating an increase in metabolic activity. These results show that the combination of morphological multiphotonimaging along with redox ratio indices can be used for the discrimination of normal and pulmonary cancertissues.

Early development of cutaneous cancer revealed by intravital nonlinear optical microscopy

We performed intravital multiphoton microscopy to image and analyze normal and carcinogen treated skintissues of nude mice in vivo. Using intravital images and the quantitative pixel to pixel ratiometric processing of multiphotonautofluorescence to second harmonic generation index (MAFSI), we can visualize the interaction between epithelial cells and extracellular matrix. We found that as the imaging depth increases, MAFSI has different distribution in normal and treated cutaneous specimens. Since the treated skin eventually became squamous cellcarcinoma, our results show that the physiological changes to mouse skin en route to become cancer can be effectively tracked by multiphoton microscopy.

Utilizing nonlinear optical microscopy to investigate the development of early cancer in nude mice in vivo

In this investigation, we used in vivo nonlinear optical microscopy to image normal and carcinogen DMBA treated skin tissues of nude mice. We acquired two-photon autofluroescence and second harmonic generation (SHG) images of the skin tissue, and applied the ASI (Autofluorescence versus SHG Index) to the resulting image. This allows us to visualize and quantify the interaction between mouse skin cells and the surrounding connective tissue. We found that as the imaging depth increases, ASI has a different distribution in the normal and the treated skin tissues. Since the DMBA treated skin eventually became squamous cell carcinoma (SCC), our results show that the physiological changes to mouse skin en route to become cancer can be effectively tracked by multiphoton microscopy. We envision this approach to be effective in studying tumor biology and tumor treatment procedures.

Investigation of the mechanism of transdermal penetration enhancer: a comparison of multiphoton microscopy and electron microscopy

The aim of this study is to characterize the ability of multiphoton microscopy in monitoring the transdermal penetration enhancing effect of a depilatory agent and the associated structural alterations of stratum corneum. The result is compared with the electron microscopic findings. Our results show that the penetration of both hydrophilic and hydrophobic agents can be enhanced. The morphology of corneocytes becomes a homogenized pattern with focal detachment of surface corneocytes. In combination with Nile red staining, multiphoton imaging also shows that the regular motar-like distribution of lipid matrix was disrupted into a homogenized pattern of lipid distribution. These results are well correlated with the findings of ultrastructural analysis by electron micrographs showing disintegration of the protein envelope of coenocytes, disruption of intracellular keratin and loss of the regular lamellar packing of intercellular lipids. We conclude that, in addition to quantifying the permeation profiles of model drugs, multiphoton microscopy is able to detect the penetration enhancer-induced structural alterations of stratum corneum.

Dorsal skinfold titanium chamber for noninvasive imaging in nude mice using multiphoton and harmonic generation microscopy

For many years, the dorsal skinfold chamber has been used for intravital observation in animal models. We have developed a chamber built using medical-grade titanium. Our design allows long-term, high resolution, and large-area observation in nude mice in vivo. Combined with two-photon fluorescence and second-harmonic generation microscopy, our chamber can be used to obtain qualitative and quantitative information for in vivo analysis of diseases such as tumors.

Optical biopsy of lung adenocarcinoma using multiphoton fluorescence and harmonic generation microscopy

Lung tumor is a major disease in Taiwan and the development of minimally invasive imaging to detect and diagnose lung tumor in vivo is of biomedical value. However, prior to in vivo investigation, it is important to obtain the multiphoton signatures associated with lung tumor ex vivo. In this investigation, we used multiphoton microscopy to image normal and cancerous lung tissues (adenocarcinoma). Our results show that a combination of harmonic generation and multiphoton autofluorescence imaging may be used to acquire structural information in discerning lung carcinoma from normal lung tissues.