scholarly journals Optical trapping in vivo: theory, practice, and applications

Nanophotonics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 1023-1040 ◽  
Author(s):  
Itia A. Favre-Bulle ◽  
Alexander B. Stilgoe ◽  
Ethan K. Scott ◽  
Halina Rubinsztein-Dunlop
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
Laser Light ◽  
Living Cells ◽  
Cellular Systems ◽  
Free Swimming ◽  
Quantitative Measurements ◽  
Swimming Bacteria ◽  
Fluorescent Nanodiamonds

AbstractSince the time of their introduction, optical tweezers (OTs) have grown to be a powerful tool in the hands of biologists. OTs use highly focused laser light to guide, manipulate, or sort target objects, typically in the nanoscale to microscale range. OTs have been particularly useful in making quantitative measurements of forces acting in cellular systems; they can reach inside living cells and be used to study the mechanical properties of the fluids and structures that they contain. As all the measurements are conducted without physically contacting the system under study, they also avoid complications related to contamination and tissue damage. From the manipulation of fluorescent nanodiamonds to chromosomes, cells, and free-swimming bacteria, OTs have now been extended to challenging biological systems such as the vestibular system in zebrafish. Here, we will give an overview of OTs, the complications that arise in carrying out OTs in vivo, and specific OT methods that have been used to address a range of otherwise inaccessible biological questions.

INFLUENCE OF ILLUMINATION CONDITIONS ON THE MEASUREMENT OF OPTICAL TWEEZERS SYSTEM

2006 ◽  
Vol 20 (06) ◽  
pp. 659-666
Author(s):  
YUQIANG JIANG ◽  
HONGLIAN GUO ◽  
CHUNXIANG LIU ◽  
ZHAOLI LI ◽  
BINGYING CHENG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
High Precision ◽  
Output Signal ◽  
Key Factors ◽  
Sample Cell ◽  
Biological Objects ◽  
Quantitative Measurements

In an optical tweezers system, the output signal of a photodiode quadrant detector and the temperature in a sample cell are two key factors for the quantitative measurements of mechanical properties of living biological objects such as cells, organelles and macro-molecules. In order to enhance the output of a quadrant detector and effectively control the temperature in a sample cell, the dependence of the temperature in the sample cell and the output of the quadrant detector for different illumination conditions are studied. The results show that appropriate illumination conditions can ensure both nearly constant temperatures in the cell and the desired output signal, which provides for the possibility of high precision and damage-free analysis of living biological objects.

Nanodiamond-enabled biomedical imaging

Nanomedicine ◽  
2020 ◽  
Vol 15 (16) ◽  
pp. 1599-1616
Author(s):  
Yen-Yiu Liu ◽  
Be-Ming Chang ◽  
Huan-Cheng Chang
Keyword(s):  
Magnetic Resonance ◽  
Contrast Agent ◽  
Biomedical Imaging ◽  
Photoacoustic Imaging ◽  
Living Cells ◽  
In Vivo Studies ◽  
Biological Processes ◽  
New Type ◽  
Fluorescent Nanodiamonds

Biomedical imaging allows in vivo studies of organisms, providing valuable information of biological processes at both cellular and tissue levels. Nanodiamonds have recently emerged as a new type of probe for fluorescence imaging and contrast agent for magnetic resonance and photoacoustic imaging. Composed of sp3-carbon atoms, diamond is chemically inert and inherently biocompatible. Uniquely, its matrix can host a variety of optically and magnetically active defects suited for bioimaging applications. Since the first production of fluorescent nanodiamonds in 2005, a large number of experiments have demonstrated that fluorescent nanodiamonds are useful as photostable markers and nanoscale sensors in living cells and organisms. In this review, we focus our discussion on the recent advancements of nanodiamond-enabled biomedical imaging for preclinical applications.

Assessment of Mechanical Properties of Adherent Living Cells by Bead Micromanipulation: Comparison of Magnetic Twisting Cytometry vs Optical Tweezers

2002 ◽  
Vol 124 (4) ◽  
pp. 408-421 ◽  
Author(s):  
Vale´rie M. Laurent ◽  
Sylvie He´non ◽  
Emmanuelle Planus ◽  
Redouane Fodil ◽  
Martial Balland ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
Viscoelastic Properties ◽  
Young Modulus ◽  
Living Cells ◽  
Alveolar Epithelial Cells ◽  
Time Constants ◽  
Alveolar Epithelial ◽  
Magnetic Twisting Cytometry ◽  
Relaxation Time Constants

We compare the measurements of viscoelastic properties of adherent alveolar epithelial cells by two micromanipulation techniques: (i) magnetic twisting cytometry and (ii) optical tweezers, using microbeads of same size and similarly attached to F-actin. The values of equivalent Young modulus E, derived from linear viscoelasticity theory, become consistent when the degree of bead immersion in the cell is taken into account. E-values are smaller in (i) than in (ii): ∼34–58 Pa vs ∼29–258 Pa, probably because higher stress in (i) reinforces nonlinearity and cellular plasticity. Otherwise, similar relaxation time constants, around 2 s, suggest similar dissipative mechanisms.

scholarly journals Influence of Illumination Conditions on Temperature in Sample Cell and the Output of a Quadrant Detector in an Optical Tweezers System

2005 ◽  
Vol 13 (3) ◽  
pp. 44-49
Author(s):  
Yuqiang Jiang ◽  
Honglian Guo ◽  
Chunxiang Liu ◽  
Zhaolin Li ◽  
Bingying Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Tweezers ◽  
Output Signal ◽  
Key Factors ◽  
Sample Cell ◽  
Biological Objects ◽  
Quantitative Measurements

In an optical tweezers system, the output signal of a photodiode quadrant detector and the temperature in a sample cell are two key factors for the quantitative measurements of mechanical properties of living biological objects such as cells, organelles and macro-molecules. In order to enhance the output of a quadrant detector and effectively control the temperature in a sample cell, the dependence of the temperature in the sample cell and the output of the quadrant detector for different illumination conditions are studied. The results show that appropriate illumination conditions can ensure both nearly constant temperatures in the cell and the desired output signal, which provides for the possibility of highprecision and damage-free analysis of living biological objects.

Label-free, mass-sensitive single-molecule imaging using interferometric scattering microscopy

2020 ◽  
Author(s):  
Nikolas Hundt
Keyword(s):  
Single Molecule ◽  
Cellular Systems ◽  
Single Molecule Imaging ◽  
Label Free ◽  
Measurement Sensitivity ◽  
Mass Distributions ◽  
Quantitative Measurements ◽  
Contrast Mechanism ◽  
Cellular Components ◽  
Scattering Signal

Abstract Single-molecule imaging has mostly been restricted to the use of fluorescence labelling as a contrast mechanism due to its superior ability to visualise molecules of interest on top of an overwhelming background of other molecules. Recently, interferometric scattering (iSCAT) microscopy has demonstrated the detection and imaging of single biomolecules based on light scattering without the need for fluorescent labels. Significant improvements in measurement sensitivity combined with a dependence of scattering signal on object size have led to the development of mass photometry, a technique that measures the mass of individual molecules and thereby determines mass distributions of biomolecule samples in solution. The experimental simplicity of mass photometry makes it a powerful tool to analyse biomolecular equilibria quantitatively with low sample consumption within minutes. When used for label-free imaging of reconstituted or cellular systems, the strict size-dependence of the iSCAT signal enables quantitative measurements of processes at size scales reaching from single-molecule observations during complex assembly up to mesoscopic dynamics of cellular components and extracellular protrusions. In this review, I would like to introduce the principles of this emerging imaging technology and discuss examples that show how mass-sensitive iSCAT can be used as a strong complement to other routine techniques in biochemistry.

Nanorobots Sense Local Physiochemical Heterogeneities of Tumor Matrisome

2020 ◽  
Author(s):  
Debayan Dasgupta ◽  
Dharma Pally ◽  
Deepak K. Saini ◽  
Ramray Bhat ◽  
Ambarish Ghosh
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Adhesive Force ◽  
Surrounding Tissue ◽  
Quantitative Measurements ◽  
Malignant Breast Tumor ◽  
Malignant Breast ◽  
Cancer Dissemination

The dissemination of cancer is brought about by continuous interaction of malignant cells with their surrounding tissue microenvironment. Understanding and quantifying the remodeling of local extracellular matrix (ECM) by invading cells can therefore provide fundamental insights into the dynamics of cancer dissemination. In this paper, we use an active and untethered nanomechanical tool, realized as magnetically driven nanorobots, to locally probe a 3D tissue culture microenvironment consisting of cancerous and non-cancerous epithelia, embedded within reconstituted basement membrane (rBM) matrix. Our assay is designed to mimic the in vivo histopathological milieu of a malignant breast tumor. We find that nanorobots preferentially adhere to the ECM near cancer cells: this is due to the distinct charge conditions of the cancer-remodeled ECM. Surprisingly, quantitative measurements estimate that the adhesive force increases with the metastatic ability of cancer cell lines, while the spatial extent of the remodeled ECM was measured to be approximately 40 μm for all cancer cell lines studied here. We hypothesized and experimentally confirmed that specific sialic acid linkages specific to cancer-secreted ECM may be a major contributing factor in determining this adhesive behavior. The findings reported here can lead to promising applications in cancer diagnosis, quantification of cancer aggression, in vivo drug delivery applications, and establishes the tremendous potential of magnetic nanorobots for fundamental studies of cancer biomechanics.

Carbon dots derived from Fusobacterium nucleatum for intracellular determination of Fe3+ and bioimaging both in vitro and in vivo

2021 ◽  
Author(s):  
Lijuan Liu ◽  
Shengting Zhang ◽  
Xiaodan Zheng ◽  
Hongmei Li ◽  
Qi Chen ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Fusobacterium Nucleatum ◽  
Living Cells ◽  
First Time ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

Fusobacterium nucleatum has been employed for the first time to synthesize fluorescent carbon dots which could be applied for the determination of Fe3+ ions in living cells and bioimaging in vitro and in vivo with excellent biocompatibility.

A Sensitive Method for Assay of Mixed-Function Oxygenase (p-450 complex) in Cell Culture

1988 ◽  
Vol 15 (3) ◽  
pp. 219-223
Author(s):  
Jørgen Clausen ◽  
Søren Achim Nielsen
Keyword(s):  
Human Lymphocytes ◽  
Cellular Systems ◽  
Metabolic Effects ◽  
Assay Method ◽  
Related Family ◽  
Oxygenase Activity ◽  
Metabolic Transformation ◽  
Mixed Function Oxygenase

The mixed-function oxygenase system involved in the metabolism of drugs and xenobiotics has been extensively studied in various animal species and in various organs (1). It is now apparent that in humans the p-450 complex is one representative of a related family, expressed by 13 c-DNA genes showing approximately 36% similarity between the different subfamilies (2). In order to compare the in vivo and in vitro metabolic effects of drugs and xenobiotics, the induction capabilities of the mixed-function oxygenase must be known. The most sensitive non-isotopic assay system for determination of mixed-function oxygenase activity is the method of Nebert & Gelboin (3,4), which is based on the metabolic transformation of benzo-(a)-pyrene to its fluorescent hydroxyl derivatives (5). However, the levels of the mixed-function oxygenase enzymes in different cellular systems show great variations, with the highest activities in liver cells. Therefore, in order to use human lymphocytes and other cellular systems with low mixed-function oxygenase activities, the assay method for determining oxygenase activity must have the highest possible sensitivity. The present communication is devoted to a study aimed at increasing the sensitivity of Nebert & Gelboin's methods for assay of mixed-function oxygenase subfamilies using benzo-(a)-pyrene as a substrate.

Sign in / Sign up

Export Citation Format

Share Document