Construction Of Light-induced Ratiometric Self-powered Sensor And Its Application In The Detection Of Steroid Hormone

As a novel detection tool,photocatalytic fuel cell（PFC）with synergetic advantages of photocatalysis and electroanalysis,has been successfully applied in the development of light-induced self-powered sensing platform.Nevertheless,the quantification of a target was realized by a single output signal in an ordinary PFC-based sensor,which is easily affected by variation of the light intensity and other environmental factors,resulting in false positive or negative errors.In this thesis,ratiometric self-powered sensor based on PFC was designed,which adopted the ratio of two signals rather than the absolute value of one signal to achieve the quantification,leading to the improvement of detection reliability.The main research contents of this paper were shown below:（Ⅰ）To improve the reliability of the detection results,a novel ratiometric self-powered sensor was constructed based on dual-channel PFC.The fabricated PFC consists of SnS₂photoanode and Pt cathode.The surface of the photoanode was modified with17β-estradiol（E2）aptamer to achieve the selective capture of E2.Under the control of multi-channel switch,the two output signals were recorded independently and the ratio of these two signals was used for the quantitation of E2.The results showed that the ratio of the maximum power density of PFCs is linearly related to the logarithm of the concentration of E2 in the range of 1-500 n M,and the detection limit is 0.12 n M（S/N=3）.The method is highly stable,selective and reproducible,and has been applied to the detection of E2 in lake water and serum samples.（Ⅱ）In this work,a multi-channel PFC was fabricated with three spatially-resolved photoanodes（PA1,PA2,and PA3）modified with SnS₂@SnO₂ and Pt cathode,which was used to construct a ratiometric self-powered sensor for the detection of cortisol（COR）and progesterone（P4）simultaneously.To achieve selective capture of COR and P4,the surfaces of PA2 and PA3 were further modified with COR and P4 aptamers,respectively.The output signal of the PFC connected to PA1 was constant,which could be used as a reference.On the contrary,the signal of the PFC connected to PA2 or PA3 changed with the concentration of the target molecules,which could be used as the working signal.The ratio of the signal on PA2 or PA3 to that on PA1 was found to be linearly related to the logarithm of COR and P4 concentration range from 1 n M to 1000 n M,1 n M to 500 n M,and the detection limit was 0.51 n M and 0.19 n M（S/N=3）,respectively.Therefore,the multi-channel PFC is highly sensitive,selective,and stable,and could achieve the detection of COR and P4 simultaneously.