Fabrication of array-type dopamine sensors using ultrasonic liquid atomizer for spraying γ-APTES/SiO2 bionanocomposite

• Main Authors: Chi-Lin Hsiao, 蕭祺霖
• Other Authors: Chin-Cheng Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/72399870932952718484

碩士 === 國立暨南國際大學 === 應用材料及光電工程學系 === 101 === The purpose of the thesis is to use the ultrasonic liquid atomizer to spray the sensing membrane of a mixture of 3-aminopropyltriethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs) onto a polysilicon wire (PSW), investigating the characteristics of electrical interference of the PSW in detectingthe nerve substance of dopamine. The ultrasonic liquid atomizer we used might rapidly spray the γ-APTES+NPs onto the PSW with the advantages of large-area production as well as with good uniformity of the film. We used two methods to do the dopamine detections: 1. Using the 4-carboxyphenylboronic acid (CPBA) to modify the surfaces of γ-APTES- or γ-APTES+NPs-coated PSWs. The CPBA molecules were then used as interfacial layer for bonding dopamine molecules (CPBA modification method). 2. Using the tyrosinase to mix with dopamine solution to produce the hydrogen ions. The γ-APTES- or γ-APTES+NPs-coated PSWs were then used to capture the hydrogen ions (tyrosinase conversion method). We found the optimal conditions for sensitivity through changing the weight ratio of NPs/γ-APTES or the volume ratio of (γ-APTES+NPs)/C2H5OH. It was found that, for both the CPBA modification and tyrosinase conversion methods, the optimal conditions for two methods were the same, that is, the weight ratio of the NPs to γ-APTES was 1% and the volume ratio of the γ-APTES+NPs to C2H5OH was 0.2%. For the optimal conditions, the dopamine sensor exhibited the best performance of sensitivity and linear detection region in dopamine detections. For the CPBA modification method, the lowest detection limit is 10-6 M, and the linear region is in the range of 10-3 M ~ 10-6 M. For the tyrosinase conversion method, the lowest detection limit is 10-11 M, and the linear region is in the range of 10-3 M ~ 10-11 M. We found that the tyrosinase conversion method is better than the CPBA surface modification method. Neverthless, both methods can be used for dopamine sensing application. We successfully fabricated the low-cost dopamine biosensor array by batch production using the ultrasonic atomizing for spraying the large–area γ-APTES +NPs membrane with good uniformity.