The V.P. C.D.R. (Vibrating Probe)

Presented by Zac EichmeyerAnd BEMsS (BioElectromagnetic student Society)

The V.P. is an instrument capable of measuring current densities in a biological mediumCapable of measuring 10 nA/cm2

It was developed in the 70’s to measure current pulses from an Oocyte

Non-Destructive measurementsCan measure activities in live cells

Offers an order of magnitude increase from current detection methods, and is more versatile than dyes

How does the V.P. Work? The V.P. works by vibrating a high

impedance probe horizontally ~10m The vibration is controlled by a

Piezoelectric Actuator The Probe is connected to a

Preamplifier which conditions the signal for the Lock-In Amplifier

The Lock-in amplifier locks the probes measurement to that of its vibration so to only read current density at its max displacement Reducing Noise, and giving a

voltage reading at the max of its amplitude

The data is then collected via a data logger and fed into a computer for analyzing

The V.P. Requirements:The probe

High impedence, greater than 5 MLow length to mass ratio

Piezoelectric Actuator (the bender)Operate between ± 45VBend at least 30m

The Lock-in AmplifierLock on to a 150 Hz – 1kHz signal

The Pre-AmpLow Noise

The DAQCapable of sampling faster than the vibration

frequency<1 kHz max

The OscillatorCapable of driving a Piezoelectric Actuator at a

frequency less then 1kHzThe Mechanical Manipulator

Connects the probe to the microscopeRigidHave 1 degree of motion (up and down) Thermally and electrically neutral

To be able to measure current densities <100 nA/cm2

To eliminate/control extraneous noiseTo build the appropriate test setup to

implement the probe with a microscope Implement into current BEMSS researchMeasure current densities in other biological

samplesTrack Ion concentrations as they relate to

Neutrophils

•The V.P. Overview(subsystems)

•Probes•Piezoelectric Actuator (Bender)•Pre Amp•Lock In Amplifier•Oscillator•DAQ•Housing •Mechanical Manipulator

•Project Overview (Top Down)