The tissues surrounding the seeds play an important role in the control of germination vigour and in the uptake of active ingredients (AIs) applied as seed dressings. The seeds can reduce costs through more efficient germination rates and have less environmental impact due to more efficient use of AIs. In this study, we use epi-detected stimulated Raman scattering (SRS) microscopy with a fiber laser source for analyzing modes of D2O into intact seeds and determining uptake kinetics. We demonstrate that SRS microscopy is an ideal tool for visualizing uptake of AIs and worthy of further applications in real field conditions.
The potential of microalgae as a source of renewable energy has received considerable interest because they can produce lipids (fatty acids and isoprenoids) that can be readily converted into biofuels. However, significant research in this area is required to increase yields to make this a viable renewable source of energy. An analytical tool that could provide quantitative in situ spectroscopic analysis of lipids synthesis in individual microalgae would significantly enhance our capability to understand the synthesis process at the cellular level and lead to the development of strategies for increasing yield. Stimulated Raman scattering (SRS) microscopy has great potential in this area however, the pump-probe signal from two-color two-photon absorption of pigments (chlorophyll and carotenoids) overwhelm the SRS signal and prevent its application. Clearly, the development of a background suppression technique is of significant value for this important research area.
To overcome the limitation of SRS in pigmented specimens, we establish a frequency-modulated stimulated Raman scattering (FM-SRS) microscopy that eliminates the non-Raman background by rapidly toggling on-and-off the targeted Raman resonance. Moreover, we perform the background-free imaging and analysis of intracellular lipid droplets and extracellular hydrocarbons in a green microalga with FM-SRS microscopy. We believe that FM-SRS microscopy demonstrates the potential for many applications in pigmented cells and provides the opportunity for improved selective visualization of the chemical composition of algae and plants
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.
We utilize multiphoton microscopy for the label-free diagnosis of noncancerous, lung adenocarcinoma (LAC), and lung squamous cell carcinoma (SCC) tissues from humans. 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 noncancerous lung tissues. Specifically, noncancerous 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) 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. Our study shows that nonlinear optical microscopy can assist in differentiating and diagnosing pulmonary cancer from noncancerous tissues.
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.
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.
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