scholarly journals Label-Free Fried Starchy Matrix: Investigation by Harmonic Generation Microscopy

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2024
Author(s):  
Agathe Chouët ◽  
Sylvie Chevallier ◽  
Romain Fleurisson ◽  
Catherine Loisel ◽  
Laurence Dubreil
Keyword(s):  
Harmonic Generation ◽  
Second Harmonic ◽  
Nile Red ◽  
Food Products ◽  
Starch Granules ◽  
Label Free ◽  
Third Harmonic ◽  
Starchy Food ◽  
Innovative Methodology ◽  
Safranin O

An innovative methodology based on non-destructive observation by using harmonic generation microscopy is proposed for detection and location of starch granules and oil in a fried starchy matrix and topography analysis of food products. Specific fluorescent probes were used to label the main biochemical components of the starchy fried matrix, namely starch and oil. Fluorescence of starch and oil respectively stained with Safranin O and Nile red was observed from non-linear microscopy. By using sequential scanning and specific emission filters, it was possible to merge fluorescence and harmonic generation signals. Second harmonic generation (SHG) generated by starch granules was superposed with safranin fluorescence, whereas third harmonic generation (THG), not restricted to the superposition with Nile red fluorescent signal, was used to investigate the topography of the fried product. By these experiments, starch granule mapping and topography of the starchy fried product were obtained without any destructive preparation of the sample. This label-free approach using harmonic generation microscopy is a very promising methodology for microstructure investigation of a large panel of starchy food products.

scholarly journals Label-Free Multiphoton Microscopy: Much More Than Fancy Images

2021 ◽  
Vol 22 (5) ◽  
pp. 2657
Author(s):  
Giulia Borile ◽  
Deborah Sandrin ◽  
Andrea Filippi ◽  
Kurt I. Anderson ◽  
Filippo Romanato
Keyword(s):  
Harmonic Generation ◽  
Biomedical Research ◽  
Quantitative Methods ◽  
Second Harmonic ◽  
Multiphoton Microscopy ◽  
Basic Research ◽  
Label Free ◽  
Multiphoton Imaging ◽  
Third Harmonic ◽  
Research Fields

Multiphoton microscopy has recently passed the milestone of its first 30 years of activity in biomedical research. The growing interest around this approach has led to a variety of applications from basic research to clinical practice. Moreover, this technique offers the advantage of label-free multiphoton imaging to analyze samples without staining processes and the need for a dedicated system. Here, we review the state of the art of label-free techniques; then, we focus on two-photon autofluorescence as well as second and third harmonic generation, describing physical and technical characteristics. We summarize some successful applications to a plethora of biomedical research fields and samples, underlying the versatility of this technique. A paragraph is dedicated to an overview of sample preparation, which is a crucial step in every microscopy experiment. Afterwards, we provide a detailed review analysis of the main quantitative methods to extract important information and parameters from acquired images using second harmonic generation. Lastly, we discuss advantages, limitations, and future perspectives in label-free multiphoton microscopy.

scholarly journals Multiphoton microscopy for label-free multicolor imaging of peripheral nerve

2021 ◽  
Author(s):  
Lars Rishøj ◽  
Iván Coto Hernández ◽  
Siddharth Ramachandran ◽  
Nate Jowett
Keyword(s):  
Peripheral Nerve ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Yellow Fluorescent Protein ◽  
Multiphoton Microscopy ◽  
Third Harmonic Generation ◽  
Second Harmonic Generation Signal ◽  
Label Free ◽  
Third Harmonic ◽  
Third Harmonic Generation Microscopy

AbstractConventional histomorphometry of peripheral nerve entails lengthy chemical processing, ultrathin sectioning in resin, and imaging by light or electron microscopy. Multiphoton microscopy techniques exist enabling label-free and in vivo imaging of histological samples. Third-harmonic-generation microscopy has recently been demonstrated effective for imaging the myelin sheath of peripheral nerve axons in animal models. Herein, we characterize use of second and third harmonic generation microscopy for label-free imaging of murine and human peripheral nerve via a novel multicolor multiphoton microscope based on a single excitation wavelength at 1300 nm. Second harmonic generation signal from collagen centered about 650 nm delineates neural connective tissue, while third harmonic general signal centered about 433 nm delineates myelin and other lipids. In transgenic mice expressing yellow fluorescent protein linked to the thy1 promoter, three-photon-excitation with emission peak at 527 nm delineates axoplasm. We compare label-free multiphoton imaging of murine and human peripheral nerve against conventional chemical stains and discuss clinical implications of this approach in guiding intraoperative decision making in nerve transfer procedures.

High-power ultrafast thin-disk multipass amplifiers for efficient laser-based manufacturing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marwan Abdou Ahmed ◽  
Christoph Roecker ◽  
André Loescher ◽  
Florian Bienert ◽  
Daniel Holder ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
State Of The Art ◽  
Second Harmonic ◽  
Average Power ◽  
Polycrystalline Diamond ◽  
Third Harmonic Generation ◽  
Thin Disk ◽  
Ultrafast Laser ◽  
Third Harmonic ◽  
Laser Systems

Abstract Thin-disk multipass amplifiers represent one of the most powerful approaches to scale the average and peak powers of ultrafast laser systems. The present paper presents the amplification of picosecond and femtosecond pulses to average powers exceeding 2 and 1 kW, respectively. Second-harmonic generation in lithium-triborate crystals with powers higher than 1.4 kW and 400 W at a wavelength of 515 nm with picosecond and femtosecond pulse durations, respectively, are also reported. Furthermore, third-harmonic generation was demonstrated with output powers exceeding 250 W at a wavelength of 343 nm. Finally, processing of silicon, metals, and polycrystalline diamond with fs pulses at an average power of 1 kW is presented to demonstrate removal rates that are improved by orders of magnitude as compared to state-of-the-art techniques.

scholarly journals Multiphoton Microscopy for Ophthalmic Imaging

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Emily A. Gibson ◽  
Omid Masihzadeh ◽  
Tim C. Lei ◽  
David A. Ammar ◽  
Malik Y. Kahook
Keyword(s):  
Harmonic Generation ◽  
Second Harmonic ◽  
Imaging Techniques ◽  
Multiphoton Microscopy ◽  
Tissue Imaging ◽  
Third Harmonic ◽  
Two Photon ◽  
Disease Mechanisms ◽  
Ophthalmic Imaging ◽  
Anti Stokes

We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third harmonic generation (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.

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