Nanosecond SRS Fiber Amplifier for Label-free Near-Infrared Photoacoustic Microscopy of Lipids

AbstractCell-tracking method has an important role in detection of metastatic circulating tumor cells (CTCs) and cell-based therapies. Label-free imaging techniques are desirable for cell-tracking because they enable long time observations without photobleaching in living cells or tissues where labeling is not always possible. Photoacoustic microscopy is a label-free imaging technique that offers rich contrast based on nonfluorescent cellular optical absorption associated with intrinsic chromophores and pigments. We show here that photoacoustic imaging is feasible for detecting very low numbers (x 104) of melanoma cells without labeling because of the strong instinct optical absorption of melanin in near-infrared wavelength. Flowing melanoma cells are imaged with micrometerresolution (40 μm) and penetration depths of centimeters (13 mm) in real-time. Photoacoustic imaging as a new cell-tracking method provides a novel modality for cancer screening and offers insights into the underlying biological process of cancer growth and metastasis and cell therapy.

Download Full-text

Cellular lensing and near infrared fluorescent nanosensor arrays to enable chemical efflux cytometry

Nature Communications ◽

10.1038/s41467-021-23416-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Soo-Yeon Cho ◽

Xun Gong ◽

Volodymyr B. Koman ◽

Matthias Kuehne ◽

Sun Jin Moon ◽

...

Keyword(s):

Near Infrared ◽

Single Cells ◽

Microfluidic Channel ◽

Human Monocyte ◽

Cellular Heterogeneity ◽

Label Free ◽

Nanotube Array ◽

Chemical Cytometry ◽

Rich Information ◽

Non Destructive

AbstractNanosensors have proven to be powerful tools to monitor single cells, achieving spatiotemporal precision even at molecular level. However, there has not been way of extending this approach to statistically relevant numbers of living cells. Herein, we design and fabricate nanosensor array in microfluidics that addresses this limitation, creating a Nanosensor Chemical Cytometry (NCC). nIR fluorescent carbon nanotube array is integrated along microfluidic channel through which flowing cells is guided. We can utilize the flowing cell itself as highly informative Gaussian lenses projecting nIR profiles and extract rich information. This unique biophotonic waveguide allows for quantified cross-correlation of biomolecular information with various physical properties and creates label-free chemical cytometer for cellular heterogeneity measurement. As an example, the NCC can profile the immune heterogeneities of human monocyte populations at attomolar sensitivity in completely non-destructive and real-time manner with rate of ~600 cells/hr, highest range demonstrated to date for state-of-the-art chemical cytometry.

Download Full-text

Applications of Vibrational Spectroscopy for Analysis of Connective Tissues

Molecules ◽

10.3390/molecules26040922 ◽

2021 ◽

Vol 26 (4) ◽

pp. 922

Author(s):

William Querido ◽

Shital Kandel ◽

Nancy Pleshko

Keyword(s):

Raman Spectroscopy ◽

Vibrational Spectroscopy ◽

Near Infrared ◽

Ex Vivo ◽

Biological Tissues ◽

Label Free ◽

Connective Tissues ◽

Bone Properties ◽

Composition And Structure

Advances in vibrational spectroscopy have propelled new insights into the molecular composition and structure of biological tissues. In this review, we discuss common modalities and techniques of vibrational spectroscopy, and present key examples to illustrate how they have been applied to enrich the assessment of connective tissues. In particular, we focus on applications of Fourier transform infrared (FTIR), near infrared (NIR) and Raman spectroscopy to assess cartilage and bone properties. We present strengths and limitations of each approach and discuss how the combination of spectrometers with microscopes (hyperspectral imaging) and fiber optic probes have greatly advanced their biomedical applications. We show how these modalities may be used to evaluate virtually any type of sample (ex vivo, in situ or in vivo) and how “spectral fingerprints” can be interpreted to quantify outcomes related to tissue composition and quality. We highlight the unparalleled advantage of vibrational spectroscopy as a label-free and often nondestructive approach to assess properties of the extracellular matrix (ECM) associated with normal, developing, aging, pathological and treated tissues. We believe this review will assist readers not only in better understanding applications of FTIR, NIR and Raman spectroscopy, but also in implementing these approaches for their own research projects.

Download Full-text

Recovery of photoacoustic images based on accurate ultrasound positioning

Visual Computing for Industry Biomedicine and Art ◽

10.1186/s42492-021-00072-2 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Yinhao Pan ◽

Ningbo Chen ◽

Liangjian Liu ◽

Chengbo Liu ◽

Zhiqiang Xu ◽

...

Keyword(s):

Biological Tissue ◽

Large Field ◽

Photoacoustic Microscopy ◽

Label Free ◽

Imaging Data ◽

Motor Speed ◽

Image Correction ◽

Microscopy Imaging ◽

Scanning Method

AbstractPhotoacoustic microscopy is an in vivo imaging technology based on the photoacoustic effect. It is widely used in various biomedical studies because it can provide high-resolution images while being label-free, safe, and harmless to biological tissue. Polygon-scanning is an effective scanning method in photoacoustic microscopy that can realize fast imaging of biological tissue with a large field of view. However, in polygon-scanning, fluctuations of the rotating motor speed and the geometric error of the rotating mirror cause image distortions, which seriously affect the photoacoustic-microscopy imaging quality. To improve the image quality of photoacoustic microscopy using polygon-scanning, an image correction method is proposed based on accurate ultrasound positioning. In this method, the photoacoustic and ultrasound imaging data of the sample are simultaneously obtained, and the angle information of each mirror used in the polygon-scanning is extracted from the ultrasonic data to correct the photoacoustic images. Experimental results show that the proposed method can significantly reduce image distortions in photoacoustic microscopy, with the image dislocation offset decreasing from 24.774 to 10.365 μm.

Download Full-text