As the first high school team of BGI-college, we endeavour to construct a paper-based cell-free system with whose function is to measure the concentration of target molecules in the sample within a certain range. What matters the most is that this attempt can be attributed into the application of bionics as the transcription and translation devices of the original cell is still present in the cell smear and thus a testing platform for a variety of molecules is created, and hereby being relieved of comprehensive limitations of using living cells for testing. This test paper integrated with biosensors for target molecules enabled the testing of the concentration of a variety of target molecules(various hormones, glucose, fatty acid or nitrates,etc.) in various clinical samples of plasma, urine or saliva. Quantitative results can be shown by the output of a variety of proteins.(light emission of GFP or the changing of colour initiated by LacZ,etc.). The high portability of the test paper and the small duration of the testing process of clinical samples, should the test paper be successfully manufactured, shall relieve millions of patients of comprehensive time-consuming and perhaps agonising medical inspections—these could be carried out at home! The test paper system, presumably, transcends mainstream medical inspections of clinical samples in means of efficiency and convenience.

Our idea originated from comprehensive discussions that eliminated the alternatives of acetochlor test papers which already exists in the market at a feasible price and the cholinesterase injection plan for protection of nerve system against Sarin gas as the project relied upon the injected medicine’s access through the Brain-Blood Barriers——an unsolvable dilemma. The idea of cell-free test paper system came up before we came across two articles that outlined the feasibility of a paper-based cell-free system for inspection of clinical samples targeting at specific molecules(1)(2). With the solid theoretical foundation and overwhelming feasibility compared to the other ideas listed above, the cell-free test paper system was chosen by the team unanimously. In late April, the designing of our plasmids was initiated via comprehensive methods, which, upon finishing even as we post this passage, has gone through three phases. Upon the biosensor’s contact with the target molecule, the genetic circuit will produce an output with the fluorescence of a GFP.

Our goals go as follows. The very foundation of our targets is to apply our cell-free system, the system of cell environment simulation which consists of cell-extract and substrate that enables DNA expression in vitro to a mature test paper module. Laboratory sample and clinical sample tests will be carried out to assess the effectiveness of the coalition. To make that happen, we will attempt on testing the feasibility of our test paper prototype in pursuit of building up a semi-quantitative test-paper system. Constant amendments, adjustments and improvements to the laboratory tasks specified in the original plans and/or to the plans themselves may be made for the better in accordance with the outcome of the attempt of putting theoretical research and arrangements into practice.

1. A Courbet, D Endy, E Renard, F Molina, Jérôme Bonnet, Detection of pathological biomarkers in human clinical samples via amplifying genetic switches and logic gates. Science Translational Medicine, Vol. 7, Issue 289, pp. 289ra83 (2015)

2. Keith Pardee, Alexander A. Green, Tom Ferrante, D. Ewen Cameron, Ajay DaleyKeyser, Peng Yin, James J. Collins, Paper-Based Synthetic Gene Networks. Cell 159, 940–954 (2014)