Spectral characteristics of two-photon autofluorescence and second harmonic generation from human skin in vivo

2011 ◽  
Author(s):  
Hans G. Breunig ◽  
Karsten König
Keyword(s):  
Second Harmonic Generation ◽  
Human Skin ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Spectral Characteristics ◽  
Two Photon

scholarly journals Nonlabeling and quantitative assessment of chondrocyte viability in articular cartilage with intrinsic nonlinear optical signatures

2020 ◽  
Vol 245 (4) ◽  
pp. 348-359 ◽  
Author(s):  
Yang Li ◽  
Xun Chen ◽  
Beckham Watkins ◽  
Neal Saini ◽  
Steven Gannon ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Second Harmonic Generation ◽  
Cell Viability ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Cartilage Tissue ◽  
Imaging Method ◽  
Chondrocyte Viability ◽  
Two Photon

Chondrocyte viability is a crucial factor for evaluating cartilage health. Most prevalent cell viability assays rely on dyes and are not applicable for in vivo or longitudinal studies. Here we demonstrated that the two-photon excited autofluorescence and second harmonic generation microscopy provided high-resolution imaging of cartilage tissue and distinguished live/dead chondrocytes by visual assessment. Furthermore, the normalized autofluorescence ratio was proposed as a quantitative indicator to determine chondrocyte viability. Based on the indicator, a curve fitting and simulated receiver operating characteristic method was proposed to identify the live/dead cell populations as well as the indicator threshold without dye labeling. Thus, it established the label-free imaging method for chondrocyte viability assay in cartilage tissue. Impact statement Chondrocytes are the only cellular component found in the cartilage, playing a critical role in maintaining the homeostasis of articular cartilage. The viability of chondrocytes is a crucial factor for evaluating cartilage health. However, the current prevalent cell viability assays rely on dye staining and thereby are not applicable in vivo or in longitudinal assessments. In this study, we demonstrate that the intrinsic signals such as two-photon excited autofluorescence and second harmonic generation can be used to classify live and dead chondrocytes in cartilage tissue. A quantitative measure is also proposed allowing development of automated assessment algorithms. The nonlabeling nature of this method suggests the potential applicability to nondestructive and in vivo assessment of cartilage health.

scholarly journals MULTIPHOTON MICROSCOPIC IMAGING OF MOUSE INTESTINAL MUCOSA BASED ON TWO-PHOTON EXCITED FLUORESCENCE AND SECOND HARMONIC GENERATION

2013 ◽  
Vol 06 (01) ◽  
pp. 1350004 ◽  
Author(s):  
REN'AN XU ◽  
XIAOQIN ZHU ◽  
NING HE ◽  
SHUANGMU ZHUO ◽  
JIAN XU ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Multiphoton Microscopy ◽  
Tissue Architecture ◽  
Intestinal Tissue ◽  
Two Photon ◽  
Main Components ◽  
Columnar Cells

Multiphoton microscopy (MPM), based on two-photon excited fluorescence and second harmonic generation, enables direct noninvasive visualization of tissue architecture and cell morphology in live tissues without the administration of exogenous contrast agents. In this paper, we used MPM to image the microstructures of the mucosa in fresh, unfixed, and unstained intestinal tissue of mouse. The morphology and distribution of the main components in mucosa layer such as columnar cells, goblet cells, intestinal glands, and a little collagen fibers were clearly observed in MPM images, and then compared with standard H&E images from paired specimens. Our results indicate that MPM combined with endoscopy and miniaturization probes has the potential application in the clinical diagnosis and in vivo monitoring of early intestinal cancer.

scholarly journals In Vivo Visualization of Collagen Transdermal Absorption by a Combined Second-harmonic Generation and Two-photon Excited Fluorescence Method

2021 ◽  
Author(s):  
yanan Sun ◽  
Shuhua Ma ◽  
Gaiying He ◽  
Weifeng Yang ◽  
Yi Wang
Keyword(s):  
Second Harmonic Generation ◽  
Real Time ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Transdermal Administration ◽  
Two Photon ◽  
Transdermal Absorption ◽  
Novel Approach

Abstract The transdermal administration of collagen is an important method used for wound healing and skin regeneration. However, due to the limitations of previous approaches, the process and degree of collagen transdermal absorption could only be quantitatively and qualitatively assessed in vitro. In the present study, we introduced a novel approach combining second-harmonic generation with two-photon excited fluorescence to visualize the dynamics of collagen transdermal absorption in vivo. The high resolution images showed that the exogenous recombinant human collagen permeated through the epidermis, reached the dermis and formed reticular structures in real time. We also validated these findings through traditional in vitro skin scanning and histological examination. Thus, our approach provides a reliable method of measurement for the real-time evaluation of collagen absorption and treatment effects.

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