title: Smartphone based visual and quantitative assays on upconversional paper sensor.
abstract: The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform.
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China. Electronic address: qsmei@hfut.edu.cn.
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Mei
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China.
authors.forename: Huarong
authors.initials: H
authors.lastname: Jing
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China.
authors.forename: You
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China.
authors.forename: Wuerzha
authors.initials: W
authors.lastname: Yisibashaer
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: School of Medical Engineering, Hefei University of Technology, Tunxi road 193, Hefei, Anhui 230009, PR China. Electronic address: bingoon@ieee.org.
authors.forename: Bing
authors.initials: B
authors.lastname: Nan Li
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117575, Singapore. Electronic address: biezy@nus.edu.sg.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D015374:Biosensing Techniques; D003300:Copper / Q000737:chemistry; D049449:Luminescence; D053758:Nanoparticles / Q000737:chemistry; D010209:Paper; D010575:Pesticides / Q000302:isolation & purification*; D066330:Printing, Three-Dimensional; D000068997:Smartphone; D013893:Thiram / Q000302:isolation & purification*; D015018:Ytterbium / Q000737:chemistry
chemical_list: D010575:Pesticides; D013893:Thiram; D003300:Copper; D015018:Ytterbium
keywords: 3D printing technology; Pesticide thiram; Smartphone; Test paper; Upconversion nanosensor