Single particle tracking
Encyclopedia
Single particle tracking (SPT) is the observation of the motion of individual particles within a medium. The coordinates (x, y, z) over a series of time steps is referred to as a trajectory
. The trajectory can be analyzed to identify modes of motion or heterogeneities in the motion such as obstacles or regions of fast transport (e.g. due to active transport or flow), in the case of random motion trajectory analysis can provide a diffusion coefficient.
2. It can also used to understand the cellular kinetics of many proteins like HIV-1 Tat Protein Transduction domain (Tat-PTD)
s diffuse in a viscous pseudo-two dimensional environment. By labeling membrane component with either an optical label (such as a gold or polystyrene bead) or a fluorescent tag a trajectory can be observed. The trajectory of lipids and proteins within the membrane of live cells have been used to infer the mechanisms affecting their motion. One of the methods to observe optical labels on cell membranes is known as nanovid microscopy
. Another interesting technique associated with particle tracking is real-time 3D particle tracking, that was used in the context of observing small complexes as they are shuttled around in or near the cell membrane.
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Trajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...
. The trajectory can be analyzed to identify modes of motion or heterogeneities in the motion such as obstacles or regions of fast transport (e.g. due to active transport or flow), in the case of random motion trajectory analysis can provide a diffusion coefficient.
Applications
1. Single Particle Tracking is used to quantify specific behaviour of a protein on the cell surface.2. It can also used to understand the cellular kinetics of many proteins like HIV-1 Tat Protein Transduction domain (Tat-PTD)
Membrane diffusion
Components of biological membraneBiological membrane
A biological membrane or biomembrane is an enclosing or separatingmembrane that acts as a selective barrier, within or around a cell. It consists of a lipid bilayer with embedded proteins that may constitute close to 50% of membrane content...
s diffuse in a viscous pseudo-two dimensional environment. By labeling membrane component with either an optical label (such as a gold or polystyrene bead) or a fluorescent tag a trajectory can be observed. The trajectory of lipids and proteins within the membrane of live cells have been used to infer the mechanisms affecting their motion. One of the methods to observe optical labels on cell membranes is known as nanovid microscopy
Nanovid microscopy
Nanovid microscopy, from “nanometer video-enhanced microscopy”, is a microscopic technique aimed at visualizing colloidal gold particles of 20-40 nm diameter as dynamic markers at the light microscopic level...
. Another interesting technique associated with particle tracking is real-time 3D particle tracking, that was used in the context of observing small complexes as they are shuttled around in or near the cell membrane.
Methods
Particle tracking can be performed using fluorescent or optical labels. The use of optical labels, such as gold nanoparticles, in SPT experiments has been termed nanovid microscopyNanovid microscopy
Nanovid microscopy, from “nanometer video-enhanced microscopy”, is a microscopic technique aimed at visualizing colloidal gold particles of 20-40 nm diameter as dynamic markers at the light microscopic level...
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See also
- lipid bilayerLipid bilayerThe lipid bilayer is a thin membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around cells. The cell membrane of almost all living organisms and many viruses are made of a lipid bilayer, as are the membranes surrounding the cell nucleus...
- biological membraneBiological membraneA biological membrane or biomembrane is an enclosing or separatingmembrane that acts as a selective barrier, within or around a cell. It consists of a lipid bilayer with embedded proteins that may constitute close to 50% of membrane content...
- Brownian motionBrownian motionBrownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
- Nanoparticle Tracking AnalysisNanoparticle tracking analysisNanoparticle Tracking Analysis is a method for visualizing and analyzing particles in liquids that relates the rate of Brownian motion to particle size. The rate of movement is related only to the viscosity and temperature of the liquid, it is not influenced by particle density or refractive index...