CN102004126A - Electrochemical biosensor and detecting method thereof - Google Patents

Abstract

The invention discloses an electrochemical biosensor and a detection method thereof. The sensor includes: a multi-channel chip electrode used as the front end of the electrochemical biosensor to convert chemical signals into electrical signals; an electrochemical detection module, It includes a signal conditioning circuit, an A/D converter and an MCU. The electrochemical detection module generates a voltage and inputs the voltage into the chip electrode. The chip electrode generates a corresponding current. The current is converted into a voltage by the signal conditioning circuit, and the voltage is passed through the A After the /D converter, the corresponding digital quantity is obtained, and then processed by the MCU; a control module is responsible for controlling the test process, realizing real-time display, controlling the experiment process and receiving test data. The invention has a humanized touch-screen man-machine interaction interface and multiple detection channels, and can be used independently or connected to a PC. Meet the needs of multiplex rapid detection in comparative and repeatable experiments. Using printed electrodes instead of conventional electrodes is more suitable for miniaturization.

Description

Electrochemical biosensor and detection method thereof

technical field

The invention relates to the technical field of electrochemical analysis, in particular to a portable multi-channel dual-purpose electrochemical biosensor and a detection method thereof.

Background technique

The portable multi-channel dual-purpose electrochemical biosensor is a complete set of electrochemical system detection and analysis equipment, which can complete the parameter tracking and analysis of the electrochemical system in various states. So far, many manufacturers at home and abroad have developed a variety of electrical analysis devices, such as potentiostats, polarographs, electrochemical analysis test systems/workstations, etc. Since the 1990s, my country has made certain achievements in the research and development of electroanalytical instruments, which has met the needs of scientific research, teaching and analytical applications to a certain extent. However, there is still a certain gap between similar foreign products. It is still a very meaningful work to improve existing products and develop new electrochemical analysis instruments.

At present, the commonly used electrochemical analysis instruments are mainly from abroad. Take the electrochemical workstation produced by American Chemical Instruments (CHI) as an example. Both 600B series general electrochemical analyzers and 1200 series handheld electrochemical analyzers need to be controlled by an external computer and work under the Windows operating system. The 600B series instruments weigh up to 7Kg, which cannot meet the portability requirements for outdoor on-site testing. Although the 1200 series instruments are small in size and light in weight, they still cannot be truly portable with an externally controlled computer.

A common portable electrochemical analyzer, such as a hand-held electrochemical analyzer disclosed in Chinese Patent No. 200610113140.5, is provided with a potentiostat, a controller and a power supply inside the instrument, and the outer surface of the instrument is provided with a liquid crystal connected to the controller. screen, keys and memory card interface; the controller is connected to the potentiostat through the interface; one end of the electrode is connected to the potentiostat through a lead wire, and the other end is exposed outside the instrument.

Both the CHI1200 series and 200610113140.5 instruments mentioned above have the advantages of small size, simple structure and convenient operation. However, both of them use serial port communication, the transmission speed is slow, and single-channel detection is used, which cannot meet the needs of multiple-channel rapid detection in comparative and repetitive experiments. 200610113140.5 achieved independent detection without external computer control, but it is still a single channel, and the button-type input method is not flexible enough, so the application of the above-mentioned electrochemical analysis instruments in some scientific research experiments and production tests has relatively large limitations.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the disadvantages that the electrochemical sensor in the prior art uses serial communication, the transmission speed is relatively slow, and single-channel detection is used, which cannot meet the needs of multi-channel rapid detection in comparative and repetitive experiments. , providing a portable multi-channel dual-purpose electrochemical biosensor and a detection method thereof.

The present invention solves the above technical problems through the following technical solutions:

An electrochemical biosensor is characterized in that it comprises:

A multi-channel chip electrode is used as the front end of the electrochemical biosensor to convert chemical signals into electrical signals;

An electrochemical detection module, which includes a signal conditioning circuit, an A/D converter, and an MCU. The electrochemical detection module generates a voltage and inputs the voltage into the chip electrode, and the chip electrode generates a corresponding current, which is converted by the signal conditioning circuit It is the voltage, and the corresponding digital quantity is obtained after the voltage passes through the A/D converter, and then processed by the MCU;

A control module is used for controlling the test process, realizing real-time display, controlling the experiment process and receiving test data.

Preferably, the electrochemical biosensor also includes a human-computer interaction module, which includes a touch screen and a mouse, and the human-computer interaction module is used for the user to directly control the experimental process.

Preferably, the multi-channel chip electrode has more than two channels.

Preferably, the multi-channel chip electrode has 16 channels.

Preferably, the control module is an ARM-based control module that works on the Windows CE operating system.

Preferably, the control module is a PC-based control module, the user directly controls the electrochemical biosensor through the PC, and the control module works on Windows 2000 or Windows XP operating system.

Preferably, the electrochemical detection module also includes a test process control module, which is used to control the switch of the electrolytic cell, control the start and pause of the test process, and set the corresponding voltage value and sensitivity of the experimental parameters.

Another technical solution of the present invention is: a detection method of the aforementioned electrochemical biosensor, which is characterized in that it comprises the following steps:

S _1. The user drops the solution to be tested on the chip electrode, and the electrochemical detection module transmits the current generated by the chip electrode to the control module;

_S2 . The control module performs data storage and data processing.

Preferably, in step _S1 , the current generated by the electrode of the chip is converted into a voltage by a signal conditioning circuit, the voltage is passed through an A/D converter to obtain a corresponding digital value, and then processed by an MCU.

The positive and progressive effect of the present invention is that the portable multi-channel dual-purpose electrochemical biosensor of the present invention has a humanized touch-screen human-computer interaction interface, multiple detection channels, and can be used independently or connected to a PC. Meet the needs of multiplex rapid detection in comparative and repeatable experiments. Also, using printed electrodes instead of conventional electrodes is more suitable for miniaturization.

Further, the printed chip electrode is effectively combined with the electrochemical biosensor, and the multi-channel electrochemical detection circuit can be used to realize simultaneous detection of 1 to 16 channels, which is more convenient and fast, has good synchronization, and reduces measurement errors. When used with printed chip electrodes, the instrument can detect whether the reagents are correctly added to the chip to save unnecessary operations for experimenters.

In addition, the embedded technology is applied to the instrument design, that is, the ARM9 series processor S3C2410 is selected as the CPU, combined with the peripheral circuit, the ARM-based Windows CE operating system is constructed, and the touch screen is combined to realize a more humanized human-computer interaction. In addition, when there is no need for portable use, it can also be connected to a PC for use, making it more convenient to operate and process data. The instrument can not only store data in U disk and SD card, but also upload data to PC through USB, or upload to network through LAN.

Description of drawings

Fig. 1 is a system block diagram of the electrochemical biosensor of the present invention.

Fig. 2 is a circuit diagram of the potentiostat of the present invention.

FIG. 3 is a circuit diagram of the signal conditioning circuit of the present invention.

FIG. 4 is a schematic diagram of the ARM-based system control module of the present invention.

FIG. 5 is a circuit diagram of the mouse interface circuit of the present invention.

Fig. 6 is a schematic diagram of the chip electrode of the present invention.

Detailed ways

The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to describe the technical solution of the present invention in detail.

As shown in Figures 1-5, the electrochemical biosensor of the present invention includes: a multi-channel chip electrode, which is used as the front end of the electrochemical biosensor to convert chemical signals into electrical signals. In this embodiment, it specifically uses Printed circuit board technology, which prints common metal electrode materials such as silicon and gold on the PCB board to realize a three-electrode system; an electrochemical detection module, which includes a signal conditioning circuit, an A/D converter and an MCU. The chemical detection module generates a voltage and inputs the voltage to the chip electrode, the chip electrode generates a corresponding current, the current is converted into a voltage through the signal conditioning circuit, the voltage is passed through the A/D converter to obtain the corresponding digital value, and then processed by the MCU ; A control module, which is responsible for controlling the test process, realizing real-time display, controlling the experiment process and receiving test data.

The main technical indicators of the electrochemical biosensor in the present embodiment are as follows:

(1) Number of channels: 16 channels

(2) Constant voltage source output voltage range: ±10V

(3) Constant voltage source output voltage resolution: <1mV

(4) Scanning speed: ≤1V/s

(5) Sampling rate: ≥1kSPS/16 channels

(6) Current measurement range: ±100mA

(7) Current measurement resolution: 0.1nA

The portable multi-channel dual-purpose electrochemical biosensor software in this embodiment includes host computer software and lower computer software. As shown in Figure 1, the upper computer program runs on the ARM-based control module, and the lower computer program runs on the test process control The module is in the AVR series microcontroller. The host computer software is based on the Windows CE operating system and is responsible for the control of the entire test process, which can realize real-time display, control the experiment process, receive test data and other functions. The software of the lower computer is based on the AVR series single-chip microcomputer, which is used to control the channel gating and A/D and D/A conversion, etc., and the corresponding channel of the device can be selected according to the actual needs. As an optional function, when no portable use is required, the user can directly control the instrument through a PC. In this mode, the corresponding upper computer software is designed and can work on Windows2000 or WindowsXP operating system. Each channel of the instrument draws the current signal from the electrode of the chip, and then obtains the voltage value corresponding to the current through the signal conditioning circuit (including I/V conversion circuit and filter circuit), and obtains the digital quantity of the voltage through the A/D converter. This digital quantity is connected to the input of the microprocessor. More specifically, the upper computer software sends corresponding control commands to the lower computer according to user requirements, and simultaneously stores data and displays measurement results, etc. The lower computer controls the scanning voltage, the opening and closing of the electrolytic cell, the selection of appropriate sensitivity, voltage conversion, data transmission, etc. according to the command.

The host computer software is responsible for the control of the entire test process, and works on the Windows CE operating system platform. Those skilled in the art can use Platform to develop underlying hardware drivers and eMbedded VisuaC++ to develop applications. The lower computer software is based on the AVR series single-chip microcomputer, uses AVR Studio to develop the program, compiles it with the GCC compiler, and performs online simulation and program download through the JTAG interface.

The upper computer software mainly realizes the loading of the underlying driver, parameter setting of the lower computer, experimental process control and data storage. It is worth mentioning that the upper computer has added a power-on self-test function. After the instrument is powered on, the system zero position is collected first. If the zero position deviation is large, the instrument has not passed the self-test and cannot proceed to the next step.

The lower computer software mainly realizes three tasks: one is to receive the control commands and related parameters sent by the upper computer, and to set the parameters of the electrochemical instrument; the second is to realize the generation of control waveforms and current collection; the third is to process the collected data and sent to the host computer.

In order to realize the optional functions of the instrument, that is, the portable multi-channel electrochemical analyzer can be controlled by a PC, a host computer program working on the Windows XP operating system was also designed, and the application program was developed using Visual C++.

The ARM-based control module is the core of the portable multi-channel dual-purpose electrochemical biosensor. The module uses the ARM9 series chip S3C2410 as the main component. Compared with other chips, the ARM9 series provides the best performance in terms of high performance and low power consumption. Its MMU supports mainstream embedded operating systems such as WindowsCE and Linux; its MPU supports real-time operating systems; it supports data and instruction Cache. As shown in Figure 4, NandFlash, SDRAM, power supply/crystal oscillator, as the basic hardware system, together constitute the system control module. The image of the WindowsCE operating system is stored in the external NandFlash, and starts from the NandFlash. When the processor is reset in this startup mode, the code will be automatically loaded into the internal SRAM and run. Afterwards, the boot program in SRAM loads the operating system image into SDRAM, and the operating system can run in SDRAM.

Among them, the basic system of the host computer based on ARM includes NandFlash, SDRAM, power supply, and crystal oscillator. In addition, it also includes a touch screen (for interacting with users), a U disk or SD card interface (for storing data), and a network port/USB port (for data transmission). The lower computer mainly includes AVR microcontroller, AD converter, filter circuit, I/V conversion circuit, potentiostat and DA converter.

Among them, the electrochemical detection module is the basis of the portable multi-channel dual-purpose electrochemical biosensor. The module takes the potentiostat as the main component, and the MCU controls and coordinates other related devices to realize current detection, as shown in the electrochemical detection module in Figure 1. The function generator composed of D/A generates voltage, and the voltage is input into the electrode of the chip through the potentiostat, and the electrode generates the corresponding current, which is converted into voltage by the signal conditioning circuit, and the voltage is converted by 16 channels of A/D to obtain the corresponding The digital quantity is processed by AVR series MCU (Mega64). The potentiostat circuit shown in Figure 2 uses U1 to form a summing circuit, so that the feedback signal of the reference electrode potential is added to the reference signal uil through the voltage follower U3, and the function of the voltage follower is to reduce the current passing through the reference electrode , this circuit is widely used in electrochemical analyzers. In the signal conditioning circuit, the input current I _in flows through the feedback resistor R _f , the low bias current of the amplifier A has little effect on the current I _in and can be ignored, the output voltage of the amplifier is calculated as follows:

V _o ＝-I _in R _f

So the output voltage V _o can be used to measure the input current. The overall sensitivity is determined by the feedback resistor _Rf . Thereby converting the current value into a voltage value.

Among them, the core device of the instrument test process control module is a microprocessor, which controls the switch of the electrolytic cell, controls the start and pause of the test process, and sets the corresponding voltage value and sensitivity of the experimental parameters according to the instructions of the host computer. The electrochemical detection of 1~16 channels can be carried out simultaneously.

The instrument data transmission module in this embodiment is mainly composed of SPI, USB and LAN. The electrochemical detection module of this portable multi-channel electrochemical analyzer adopts the SPI interface to connect with the host computer with ARM9 as the processor to transmit control commands, etc. The instrument works on the Windows CE operating system. In this mode, the user can upload the experimental data to the network through LAN, and store it in the U disk or SD card through USB. Another feature of this instrument is: when there is no need for portable use, the user can directly control the instrument through the PC, and the instrument transmits control commands through the USB interface, and at the same time receives the experimental data during the test. At this point, the PC can work on Windows2000 or Windows XP operating system. Obviously, the instrument meets the needs of portability for outdoor testing and convenience for laboratory testing.

The electrochemical detection module of this portable multi-channel dual-purpose electrochemical biosensor uses SPI to connect with ARM9 to transmit control commands and test data. The instrument works on the WindowsCE operating system. When there is no need for portable use, the user can directly control the instrument through the PC. In this mode, the instrument communicates through the USB interface, and the PC can work on Windows2000 and WindowsXP operating systems. The PC sends the control commands to the lower computer through the USB, and the lower computer sends the acquisition signal to the upper computer through the USB.

The human-computer interaction module of the instrument is composed of a touch screen and a mouse. Users can use the instrument through the touch screen like using an iPhone, or use the instrument through the mouse. Compared with the button operation of traditional instruments, it is more humanized. The human-computer interaction module runs under the Windows CE operating system provided by the ARM-based control module. The Windows CE operating system is similar to the Windows XP operating system. It has its own drivers for the mouse and touch screen, so it only needs to design the corresponding hardware circuit. direct drive. The touch screen interface circuit only needs to lead out the control leads that come with the ARM. The circuit diagram of the mouse interface is shown in Figure 5. When using a USB mouse, you only need to short the pins 2 and 3 of J13/J14 in the figure, and connect the The mouse can be used by plugging it into J15. Through the host computer software, the user directly controls the experimental process, and at the same time, the experimental data will be saved to the U disk or SD card connected to the host computer to facilitate the next data processing for the user.

In addition, in this embodiment, a 16-channel printed chip electrode matching the instrument is used. Compared with the traditional gold electrode and silicon electrode, the chip electrode has the advantages of low price, easy to carry and operate, and multiple channels. These advantages make the use of Chip electrodes have gradually become a trend in electrochemical analysis. The chip electrode in this embodiment uses 97% alumina ceramics as the base, and is plated with pure gold on it according to the existing three-electrode system. Each circular structure is an independent system, the middle point is the working electrode 2, the right point is the reference electrode 3, and the left point is the counter electrode 1, as shown in Figure 6.

When the electrochemical biosensor of the present invention is detected, the user drops the solution to be tested on the electrode of the printed chip, and the electrochemical detection module transmits the current generated by the electrode of the chip to the ARM-based control module for data storage and data processing, and finally Presented to users through human interaction modules. In this embodiment, the current generated by the chip electrode is converted into a voltage by a signal conditioning circuit, and the voltage is passed through an A/D converter to obtain a corresponding digital value, and then processed by an MCU. The electrochemical biosensor of the present invention can perform electrochemical detection of 16 channels at the same time, control the testing process, assist staff to check whether reagents are added correctly, set experimental parameters, and the like.

The electrochemical biosensor of the present invention also has a power-on self-check function, so that the user can judge whether the instrument is working normally without resorting to an external measurement system; the self-check is divided into two types: power-on self-check and manual self-check. The instrument has the function of automatically adjusting the sensitivity, which saves the time of exploring experimental conditions when researching new chemical reagents.

The detection instrument also has the characteristics of high efficiency, rapidity, low price and convenience, and is suitable for electroanalytical chemical detection using printed chip electrodes, which is suitable for laboratory scientific research and outdoor on-site detection. Therefore, the present invention has good industrialization prospects and conforms to the current market situation.

Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (9)

1. electrochemica biological sensor is characterized in that it comprises:

One multi-channel chip electrode is used for the front end as this electrochemica biological sensor, and chemical signal is converted to electric signal;

One Electrochemical Detection module, it comprises signal conditioning circuit, A/D converter and MCU, this Electrochemical Detection module produces voltage, and voltage is input in the chip electrode, chip electrode produces corresponding electric current, electric current is converted to voltage by signal conditioning circuit, and voltage obtains the corresponding digital amount after by A/D converter, handles by MCU again;

One control module is used for being responsible for the control testing process, realizes showing in real time, controlling the experiment process and receive and detect data.

2. electrochemica biological sensor as claimed in claim 1 is characterized in that this electrochemica biological sensor also comprises a human-computer interaction module, and it comprises touch-screen and mouse, and this human-computer interaction module is used for the user and directly controls experimentation.

3. electrochemica biological sensor as claimed in claim 1 is characterized in that, this multi-channel chip electrode has plural passage.

4. electrochemica biological sensor as claimed in claim 3 is characterized in that, this multi-channel chip electrode is 16 passages.

5. electrochemica biological sensor as claimed in claim 1 is characterized in that this control module is the control module based on ARM, works in Windows CE operating system.

6. electrochemica biological sensor as claimed in claim 1, it is characterized in that, this control module is the control module based on PC, and the user directly controls this electrochemica biological sensor by PC, and this control module works in Windows 2000 or Windows XP operating system.

7. electrochemica biological sensor as claimed in claim 1, it is characterized in that, this Electrochemical Detection module also comprises a testing process control module, be used to control electrolytic cell switch, control test process beginning and time-out and experiment parameter correspondent voltage value, sensitivity are set.

8. the detection method of an electrochemica biological sensor as claimed in claim 1 is characterized in that, it may further comprise the steps:

S1, user are added in drips of solution to be measured on the chip electrode, and the Electrochemical Detection module is given control module with the current delivery that chip electrode produces;

S2, this control module are carried out data and are preserved and data processing.

9. the detection method of electrochemica biological sensor as claimed in claim 8, it is characterized in that among the step S1, the electric current that chip electrode produces is converted to voltage by signal conditioning circuit, voltage obtains the corresponding digital amount after by A/D converter, handles by MCU again.

Images