A SICM voltage modulation imaging device and method based on differential noise reduction

Abstract

The invention relates to a differential-noise-reduction-based SICM voltage modulation imaging device and method. The device comprises a voltage driving unit, a current detecting unit, a signal modulating unit, a feedback control unit and a mechanism executing unit. In addition, the method includes the flowing steps that: a signal generator generates two paths of co-frequency alternating current voltages, wherein one path of voltage is connected to a patch clamp amplifier to serve as a driving voltage and the other path of voltage is connected to a lock-in amplifier to serve as a reference voltage; capacitance compensation is performed by the patch clamp amplifier; one path of modulation voltage having the same frequency and same phase as the reference signal is connected to the lock-in amplifier to carry out feedback signal modulation; calculation is carried out to obtain a new current setting value; and the lock-in amplifier feeds back an extracted current component to a controller, adistance between the probe and the sample is controlled, a track of the relative displacement of the probe and the sample is recorded, and thus image scanning is completed. According to the invention, the feedback signal is modulated to increase the amplitude of the driving voltage, so that the signal-to-noise ratio of the system is improved and thus the Z-direction resolution ratio and the scanning speed of the SICM system are improved.

Description

technical field [0001] The invention relates to a novel fast and high-resolution micro-nano-level non-contact imaging technology, in particular to a scanning device and method based on differential noise reduction scanning ion conductance microscope (SICM) voltage modulation imaging mode. Background technique [0002] At present, scanning ion conductance microscope (SICM) is a scanning probe microscopy technique for imaging at the nanoscale and characterizing biological samples in various ways. It has been widely used in biology, medicine, chemistry, materials and many other fields. The biggest feature of SICM is that it can conduct non-destructive observation of living cells under physiological conditions, and does not require pretreatment such as fluorescent labeling of samples. Therefore, it is a high-resolution, high-fidelity imaging technology. The method is especially suitable for the observation of soft samples such as living cells. SICM uses a hollow glass tube wit...

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Problems solved by technology

When the system hardware and environmental conditions are fixed, the noise level remains unchanged, and the amplitude of the effective signal can be increased by increasing the driving voltage across the electrodes, but limited by the input range of the lock-in amplifier, the driving voltage can only be increased within a limited range , so the signal-to-noise ratio cannot be further improved

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