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Human C-reactive protein (CRP) is an established inflammatory biomarker and was proved to be potentially relevant to disease pathology and cancer progression. A large body of methodologies have been reported for CRP analysis, including electrochemical/optical biosensors, aptamer, or antibody-based detection. Although the detection limit is rather low until pg/uL, most of which are time-consuming and relatively expensive, and few of them provided CRP single-molecule information. This work demonstrated the nanopore-based approach for the characterization of CRP conformation under versatile conditions. With an optimized pore of 14 nm in diameter, we achieved the detection limit as low as 0.3 ng/μL, voltage polarity significantly influences the electro-osmotic force and CRP translocation behavior, and the pentameric conformation of CRP may dissociate into pro-inflammatory CRP isoforms and monomeric CRP at bias potential above 300 mV. CRP tends to translocate through nanopores faster along with the increase in pH values, due to more surface charge on both CRP and pore inner wall and stronger electro-osmotic force. The CRP could specifically bind with its aptamer of different concentrations to form complexes, and the complexes exhibited distinguishable nanopore translocation behavior compared with CRP alone. The variation of the molar ratio of aptamer significantly influences the orientation of CRP translocation. The plasma test under physiological conditions displayed the ability of the nanopore system on the CRP identification with a concentration of 3 ng/μL.

Mucin 1(MUC1) is an effective marker of breast cancer, so it is of great significance to develop a simple, sensitive and highly selective MUC1 detection sensor. Herein, we constructed a label-free nanopore biosensor for rapid and highly sensitive detection of MUC1. The presence of MUC1 triggered the modification of the DNAzyme walking chain on the surface of Fe

In this paper, a novel detection technique for tumor marker carcinoembryonic antigen (CEA) has been developed by using a solid-state nanopore as a tool. The system utilizes the specific affinity between aptamer-modified magnetic Fe

In order to solve the problem of lack of effective and real-time monitoring evaluation method for electron beam selective melting (EBSM) processing, a technique of acquiring real-time secondary electron (SE) imaging through layer-by-layer scanning is presented, which could monitor the defects of components. Basic design scheme, including the Electron beam scanning system, signal processing and imaging system, is introduced in this paper. Capability of generating digital image and choosing different monitoring area for the real-time monitoring system has been verified by series of experiments. Results suggest that the maximum resolution of the prototype has reached 0.3mm.

Affected by defocusing and astigmatism, the quality of electron beam steadily deteriorated with increasing deflection distance, limiting the processing area of SEBM machines. The relationship among beam spot size, deflection distance and deflection direction are studied by numerical simulation, which explains the cause of decreasing power density. The experimental results show that defocus is the main factor affecting the beam spot size when the deflection distance is less than 100 mm and astigmatism is the main factor at a larger deflection distance. Then, the chessboard electron imaging experiment is carried out to verify that the spot size increases with the deflection distance. Thus, dynamic focusing and astigmatism should be introduced at the same time to minimize beam area.

Active disturbance rejection control (ADRC) as an alternative to classical PID control to solving control problems, has gained significant traction these years. With its simple tuning method, robustness against process parameter variations and ability of disturbance rejection, we tried it in our homemade fast atomic force microscope (AFM). Experiments are carried out in contact mode on standard optical grating sample with 50Hz line rate. The results show that ADRC can reject external disturbances well, and can reduce system vibrations obviously.

As AFM tip approach speed is one of the key factors for AFM industrial on-line detection application, a sectional fast tip approach method composed of rough approach and mild approach processes is introduced here. In rough approach process, AFM tip can be approached by step motor to certain distance upon the sample surface with high speed, as a homemade dual-channel reflective intensity modulated fiber optic displacement sensor (DC-RIMFODS) can be integrated to AFM scan head easily to detect the stop position. While continued with mild approach process after rough approach, step motor can run slowly with a common PI feedback controller for Z scanner to make the tip get in touch with sample surface softly. Experimental results show that with the well-defined fiber optical sensor positioning accuracy and repeatability, the tip-sample distance can be limited in certain range after rough approach with 1mm/s high speed, and the whole AFM tip approach process can be finished in 20s by continuing with mild approach, while the initial tip-sample distance is about 10mm.

Micron and nanometer dimensional metrology is an important part of integrated circuits manufacturing system and nanofabrication research work. Semiconductor device feature size has shrunk from the micron to dozen of nanometers. How to watch the micro structure clearly, identify its edge, and measure its dimension accurately are the major issues that need to be research. In this paper, a metrological scanning electron microscope (M-SEM) system with precision stage and laser interferometer is presented. Furthermore, this paper focuses on demonstrating a metrological SEM image edge detection algorithm which is the essential part of the metrological SEM system to realize the measurement of line width. The procedure of the algorithm is that SEM image is first analyzed by noise type according to the histogram characteristics. Then the image noise is reduced by specific filters. Furthermore, a specific interesting object image region is selected and pixel gray level values of the region are obtained by line scan. SEM image edges are determined by the characteristic of the pixel information in two possible cases. This algorithm preserves the edge details of the original image and detects the image edge automatically in an easy and fast way.

The small spatial displacement of the piezo tube scanner limits the AFM(Atomic Force Microscopy) scanning range, especially when facing up to cell topography scanning. And the low dynamic property of normal AFM tube scanner tube restricts the imaging speed. In order to achieve large scanning range and rapid scanning motion simultaneously, a special atomic force microscopy is designed. The 100um scanning range is obtained by the new scanner which is composed of the flexure guide structure instead of peizo tube. Furthermore, a new acquiring image method is used to eliminating AFM nonlinearity error. Using this scanning system, some large biological cells are imaged in liquid environments with 30 lines per second.

The system completes the design of signal generator by using the technology of the Direct Digital Synthesizer (DDS). The DSP6713 designed as a key device, realizes outputting triangle wave and sine wave. The digital to analog (D/A) converter circuit is composed of AD768 and LTC1597, which helps improve the speed of converting and modulate the range of the output voltage by Digital Signal Processor (DSP), comparing with using one chip of D/A and proportional amplifier. In addition, bus topology makes extending system functions become easy. The system can be widely used in such field as communication, automatic control and instruments.

We address the modelling of tip-cell membrane interactions under high speed atomic force microscopy. Using a home-made device with a scanning area of 100 × 100 μm(2), in situ imaging of living cells is successfully performed under loading rates from 1 to 50 Hz, intending to enable detailed descriptions of physiological processes in living samples.

A semiconductor navigation system based on Scanning Electron Microscope has been developed to fast locate the smallest defects which can bring wafer production to a waster. The mainly parts of the navigation system are pattern acquisition model and scanning model. The pattern acquisition model is made up of an Analog-to-Digital Convertor, a CPLD and a Static RAM. The electron-beam is controlled by scanning model to scan the wafer. In the same time, the pattern acquisition model gathers the secondary electrons reflected by wafer and converts them to gray value. Those gray values of each point in scanning field are transmitted to computer through USB2.0 interface, and assembled to a whole pattern of wafer production according to the "lattice principle" by succeeding software. Legible wafer pattern is obtained by using this system.