Smartphone-Base Detection System For The Digital Colorimetry Inspired By Two-Dimensional Barcode

With the development of science and technology,smartphone becomes widely favored by the people,due to its powerful function for data processing,image acquisition,and the open application platform.The two-dimensional barcode technique shows powerful functions for information acquisition and processing,so it has become one of the hottest research areas to develop a new biochemical detection technique,combining the smartphone with barcode technology,In this thesis,smartphone was used as a testing tool,combined two-dimensional barcode technique and color reaction principle,and such a new method was proposed for the molecular detection.Since the error correcting code in the conventional QR Code is quite complex,and difficult to be developed as tool for biodetection,we wrote a mobile application(App)using the Java language,by deleting the error correcting code in traditional twodimensional barcode.This App can generate two-dimensional barcode with simple structure,which can be used for decode analysis and biodetection analysis by the mobile application.The two dimensional arrays were printed by 3D printer,paper microfluidic chips and printed LEGO modules were used as the channels,respectively.After the color reaction of analyte in solution,the products were added into the channels,resulting the biological barcode.If the barcode decoding results are the same as the initial results,indicating that the solution dose not contain the analyte or the concentration of analyte is low.If the barcode decoding results are different from the initial results,indicating the high concentration of analyte,then we can use the App for further quantitative analysis.Excessive nitrite is great harm to human.In this paper,nitrite was detected as an example,the detection results of colorimetric methods were agreed with the results by Photoshop method and absorption spectroscopic method,respectively,indicating the feasibility of this method.The main content of this thesis are as follows:1.Since LEGO modules can be assembled freely,the detection channels with same size of LEGO modules were prepared by 3D printer,and assembled with LEGO modules to form the two-dimensional barcode(QR Code)style detection pattern.2.QR Code generated by the mobile phone App was printed onto the filter paper,the reaction channels of QR code were cut from filter paper and casted the color reaction products.When the channels become dry,they were paste back to the corresponding area of QR code,forming the biological barcode for detection.Finally,the rapid detection of nitrite in water was carried out by using mobile phone App with analysis function.3.A colorimetric analysis system based on smartphone was developed for the further analysis of positive and negative samples.According to the result of decoding,the color information of the samples in the channel was captured.The calibration equation was obtained through fitting the curves between the known standard concentration of the samples and the corresponding R,G,B value.The concentration can be calculated by using the calibration equation and the R,G,B value of the color reaction products from the sample,and the results can be directly display onto the smartphone.4.As an example,the detection of nitrite was completed by using the detection system based on App and smartphones,the detection range of is 0-10 mg/L.The detection results were compared with traditional Photoshop software and ansorption spectroscopic method,respectively,and the results were consistent,indicating the feasibility of this method.