Research And Design Of Printing Arrayer For Making Chemical Sensor Arrays

With the development of chemical sensors, and the requirement of simple, convenient, fast, and widely applicable testing analysis methods, the array type chemical sensors arises at the historic moment. They are widely used in the scientific research and actual life, especially reflecting huge application potential in the analysis of complex compounds. Due to the high sensitivity, high response speed and integration feature of array type chemical sensors, they are widely used in the detection of food, sugar, toxic gas and disease and so on.Lots of research results show that porphyrin and derivatives as the sensing element have high sensitivity and chemical stability, especially reflecting the special features in the aspect of specific identification and appraisal. Therefore, how to build the reliable visualization porphyrin chemical sensor arrays has important significance to the research of multidisciplinary cross area. The reagent for making chemical sensor arrays like porphyrin chemical sensor arrays has corrosion resistance, easy to volatile, mixed characteristics. Due to the accuracy requirement, every point in the same array should keep similar size. However, the point made from different kinds of reagent that has different diffusion velocity, hardly can spread similar length in the same time. Nowadays, there are not devices for making the special arrays on the market and patent report. The similar device in the function is biochip printing device, while it generally spots DNA and proteins and can not absorb highly corrosive and volatile reagent. Therefore, gene microarray device can not make the special sensor arrays. In view of this, this paper aims to provide a device for making chemical sensor arrays automatically. The device can absorb high corrosive reagent and making chemical sensor arrays automatically, meanwhile the chemical sensor arrays can meet the testing requirement.In this paper, the main study is completed as follows:1. Designing the overall structure of array type chemical sensor printing device based on the working principle of contact biochip printing arrayer. The structure requirements of chemical sensor printing arrayer are as follows: 1. Achieving the goal of free movement in the direction of X and Y axis. 2. The printing head can install 36 kinds of printing pins with different radius. 3. The 36 printing pins can absorb reagent in the same time. 4. Making many chemical sensors continuously. 5. The reagent tank can holding high corrosive chemical reagent.2. Based on the overall structure of the printing arrayer and the function which the arrayer should have, this paper designs the hardware system in the core of PIC16F877 A MCU, including Matrix keyboard circuit, position detection circuit, LCD displaying circuit, drive circuit. The software programming of whole control system is completed in the MPLAB.3. Various reagent with different diffusion velocity hardly can spread similar length in the same time. In order to solve the question, based on the capillary fluid model, Washburn and Laplace equation and so on, this paper builds the liquid spreading model, which aims to achieve the goal of various reagent can spread similar length in the same time.4. Testing every module of system, detecting them whether they can work normally, then the printing arrayer is assembled.5. Through the comparison of euclidean distance and relative standard deviation of sensitive point in two kinds of differential spectra array, the results show that the chemical sensor arrays made by printing arrayer are more stability and react more strongly with VOCs than the chemical sensor arrays made by handwork.