Rotary Valve-Assisted Fluidic System Coupling with CRISPR/Cas12a for Fully Integrated Nucleic Acid Detection.

Of late, many nucleic acid analysis platforms have been established, but there is still room for constructing integrated nucleic acid detection systems with high nucleic acid extraction efficiency, low detection cost, and convenient operation. In this work, a simple rotary valve-assisted fluidic chip coupling with CRISPR/Cas12a was established to achieve fully integrated nucleic acid detection. All of the detection reagents were prestored on the fluidic chip. With the aid of the rotary valve and syringe, the liquid flow and stirring can be precisely controlled. The nucleic acid extraction, loop-mediated isothermal amplification (LAMP) reaction, and CRISPR detection could be completed in 80 min. A clean reservoir and an air reservoir on the fluidic chip were designed to effectively remove the remaining ethanol. With Vibrio parahaemolyticus as the targets, the detection sensitivity of the fluidic chip could reach 3.1 × 101 copies of target DNA per reaction. A positive sample could be sensitively detected by CRISPR/Cas12a to produce a green fluorescent signal, while a negative sample generated no fluorescent signal. Further, the fluidic chip was successfully applied for detection of spiked shrimp samples, which showed the same detection sensitivity. A great feasibility for real-sample detection was showed by the fluidic chip. The proposed detection platform did not need expensive centrifugal instruments or pumps, which displayed its potential to become a powerful tool for food safety analysis and clinical diagnostics, especially in the resource-limited areas.

A reversible valve-assisted chip coupling with integrated sample treatment and CRISPR/Cas12a for visual detection of Vibrio parahaemolyticus.

Vibrio parahaemolyticus (V. parahaemolyticus) is regarded as a major cause of seafood-associated illnesses, which has aroused widespread public concern. Here, a rapid and convenient detection method for V. parahaemolyticus detection was established by a reversible valve-assisted chip coupling with CRISPR/Cas12a. With optimized lysis buffer, loop mediated isothermal amplification (LAMP) reagents and CRISPR reagents, the whole detection process from sampling to results could be finished within 50 min. The structure of chip was simple and the cost was low. By relying on three reversible rotary valves and the rotation direction-dependent Coriolis pseudo force, the flow order of liquid and the direction of liquid flow could be precisely controlled. The LAMP amplicons were specifically and sensitively identified by CRISPR/Cas12a. Positive amplification would produce green fluorescent signal while negative amplification generated no fluorescent signal, which could be clearly distinguished by the naked eye. With 600 µL of samples processed, the limit of detection (LOD) for both pure cultured V. parahaemolyticus or spiked shrimp samples could achieve 30 copies/reaction. These illustrated the established method displayed great feasibility for real samples detection. In the future, the chip could also combine with other amplification reactions, like PCR or recombinase polymerase amplification reaction (RPA), to conduct detection by changing the corresponding lyophilized amplification reagents. Overall, the proposed detection platform displays great potential for food safety analysis and clinical diagnostics, especially in resource-limited areas.

[The design of an electromyogram-guided treatment instrument].

The text introduces an electromyogram-guided treatment instrument with simple operation and lower cost, and it is easy to find the lesion muscle. Its clinical tests have shown a satisfying result.

[Research on ECG-monitoring based on the technology of virtual instruments].

A ECG-monitoring system based on the technology of virtual instruments, has been developed. Its advantages involve real-time ECG-display and alarm for abnormal heart rate,low cost and flexibility of function-expanding . And most functions of the system are completed by software instead of hardware. The preliminary experimental results indicate that the system's delay time is less than 2 s, meeting the requirements of real time monitoring.