Sensors enter the era of low-dimensional organic materials

Recently, Zhao Yongsheng, a key laboratory of the Institute of Chemistry, Institute of Chemistry, Chinese Academy of Sciences, used a one-dimensional nanomaterial with a high specific surface area to prepare a more sensitive electrochemical nano-biosensor. Due to its unique structure and novel physical and chemical properties, organic low-dimensional nanomaterials have broad application prospects in the field of biosensing.

Biosensors are sensors made of immobilized biological components such as enzymes, antigens, antibodies, hormones, etc., or biological cells, organelles, tissues, and the like as sensing elements.

Improved detection performance

From bacteria to humans, all living organisms use "biological molecular switches" to monitor the environment. Such "switches" are molecules that can be made of RNA or protein and can change shape. The attraction of these "molecular switches" is that they are small enough to "work" within cells and are very targeted enough to deal with very complex environments. Inspired by these natural "switches," nano-biosensors came into being.

In 2012, the Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Suzhou Institute of Nanotechnology and Nano-Bionics, Zhongshan Hospital, Fudan University, and Shanghai Institute of Metrology and Measurement Technology co-developed an electrochemical biosensor based on a DNA nanostructure-modified interface for microRNAs. Ultrasensitive detection of tumor targets.

Compared with conventional homogeneous detection methods such as PCR, electrochemical biosensors based on surface reactions have the advantages of cheaper and easier detection of disease-associated microRNAs. However, the sensitivity of electrochemical biosensors is often limited by interfacial mass transfer processes and crowding effects. In order to solve these problems, Fan Chunhai and his team have previously developed a new method of using three-dimensional DNA nanostructures to modify the surface of gold electrodes, which can significantly enhance the binding ability of surface molecules and improve detection sensitivity.

In 2012, researchers at institutions such as Purdue University in the United States created novel biosensors that can perform non-invasive diabetes tests to detect the extremely low glucose concentrations in human saliva and tears. This technique does not require tedious production steps, which can reduce the manufacturing cost of the sensor and may help eliminate or reduce the chance of using acupuncture for diabetes testing.

The new biosensor consists of three main parts: nanosheets made of graphene, platinum nanoparticles, and glucose oxidase. The nanosheets are like tiny rose petals. Each petal contains multiple stacked graphene layers. The edges of the petals are also hung with incomplete chemical bonds so that the platinum nanoparticles can adhere here. The combination of nanoplatelets and platinum nanoparticles can form electrodes, and glucose oxidase can also attach to platinum nanoparticles. Enzymes convert glucose to peroxides and produce a signal on the electrodes.

Low-dimensional organic materials epoch-making development

Industry insiders point out that after nanomaterials are applied in the field of electrochemical biosensors, not only the detection performance of the sensor is improved, but also the chemical and physical properties of the sensor and its detection sensitivity to biomolecules or cells are improved, and the detection time is also shortened. At the same time, it also achieved high-throughput real-time analysis and detection. This study also provides important theoretical and experimental evidence for the preparation of biosensors from low-dimensional nanomaterials.

Sensors have contributed to the rapid and orderly development of the robotics industry. The sensor is used to detect the robot's own working status, and the robot's intelligent detection of the external working environment and the status of the object's core components. A device or device that can sense the prescribed measurements and convert it into usable output signals according to a certain law.

Nanomaterials have a small size effect, a surface effect, a quantum size effect, and a macroscopic quantum tunneling effect, making them exhibit singular chemical and physical properties. Previously, researchers had used agarose to immobilize glucose oxidase and ferrocene-attached single-walled carbon nanotubes on the surface of a glassy carbon electrode, enabling rapid and sensitive detection of glucose. The introduction of carbon nanotubes can also significantly increase the redox reversibility of the electroactive material in the electrochemically sensitive film while eliminating the interference of dissolved oxygen on the measurement.