Particle counting system of micro-fluidic chip based on electric resistance technology

Abstract

The invention discloses a particle counting system of a micro-fluidic chip based on an electric resistance technology. The system comprises a micro-fluidic chip and a signal detection circuit. The micro-fluidic chip comprises a glass substrate, a PDMS substrate and two pairs of metal needles used as electrodes. Normal conductive metal needles are utilized as the electrodes of the micro-fluidic chip to produce an electric field which is across a micro-channel, therefore the preparation process of the micro-fluidic chip is comparatively simple and the production cost is comparatively low. The signal detection circuit comprises two I / V conversion circuit, a differential circuit, an envelope detection circuit, a high-pass filter circuit, a low-pass filter circuit and an amplifying circuit. The resistance signals are detected in the signal detection circuit by utilizing signal differential detection method to ensure precision of signal detection.

Description

technical field [0001] The invention relates to a particle counting system, in particular to a microfluidic chip particle counting system based on electrical impedance technology, which belongs to the technical field of electrical detection. Background technique [0002] Electrical impedance counting technology is the earliest automated technology for particle / cell counting. Since the particles / cells can be regarded as insulating objects to a certain extent, when the particles / cells pass through the electric field in a certain fixed area, the impedance of the fixed electric field area will increase; when the particles / cells leave the electric field area, the impedance will return to normal ; The size of the impedance signal is proportional to the volume of the particle / cell. Therefore, people use this feature to count and classify particles / cells. However, the current commercial electrical impedance counters are generally relatively large and cannot meet the requirements o...

AI Technical Summary

Problems solved by technology

[0005] At the same time, in the current microfluidic chip particle counting device, due to the low signal-to-noise ratio, the detection system generally adopts more complicated technologies, such as synchronous detection technology, or uses very expensive instruments, such as lock-in amplifiers, etc. Detection of Weak Signals

The cost burden of the whole device is very high, and at the same time, the dedicated instrument cannot meet the requirements of portability and low cost

Images