13) Electrophoresis In medicine Flashcards
Electrophoresis definition and types
The motion of the dispersed phase relative to the fluid caused by external electrical force
There is cell electrophoresis
And molecular electrophoresis
Electrophoretic mobility
The terminal velocity of the dispersed phase at electric field strength (E).
u=v/E
Forces acting on moving particles
The motion is due to electrics force Fe
The drag force Fd opposes the electrical force
When both forces are balanced particles move with constant terminal velocity
Fe=fd
Electrophoretic mobility for spherical particles
U= q/6pinr
Electrophoretic mobility for any shape
U=qD/KT
Measurement of electrophoretic mobility
Determined experimentally from measurements of particle velocity and electric field strength
Used for the experimental evaluation of zeta potential
Electrophollic mobilty in fluids
Squiggle=Q/4PIęr
ę = electrical permittivity of fluid
U=2 squiggle ę / 3n
Electrophoretic mobility vs pH
If the dispersion pH changes:
The density of surface charge changes
Zeta potential changes
Electrophoretic mobility changes
Decreasing density of surface charge
Smaller value of zeta potential
Smaller electrophoretic mobility
Isoelectric point
The fluid pH value at which the electrophoretic mobility of the suspended particles vanishes
Passing through the isoelectric point ch ages the sigh of the zeta potential and electrophoretic mobility
Electrophoretic mobility vs ionic strength
Increasing the ionic strength of a solution results in
Smaller value for the zeta potential
Smaller electrophoretic mobility
Flocculation
The infraction between identically charged particles in a solution depends on the relative strength of the 2 forces
Vanderwalls forces
Electrostatic repelling forces
Increasing ionic strength results in greater attractive force causing particles to settle at the bottom
Applications of electrophoresis in medicine
Investigation of interaction between cells
Paternity testing
Vaccinations
Immunoelectrophoresis used for separation of proteins with only slightly differing electrophoretic mobility. Used to discoverer separate proteins
Applications of cell electrophoresis
Separation of protein molecules or nucleus acids bc each molecule has different charge to mass ratio aswell as mobility
Used for analytic of preparative techniques
Molecules electrophoresis
Molecules are suspended in buffers
Electrical field moves the molecule across the solid medium
Can use chromatography paper
Gels such as agarose
✍️
Gel electrophoresis
Solution is placed only the afar gel and is connected to power supply. The dna is negatively charged so it will move towards the positively charged cathode.
Paper electrophoresis and vertical electrophoresis are also types of electrophoresis
