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Biotin-functionalized semiconducting polymer in an organic field effect transistor and application as a biosensor.

Kim ZS, Lim SC, Kim SH, Yang YS, Hwang DH - Sensors (Basel) (2012)

Bottom Line: The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2.The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors.Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA.

View Article: PubMed Central - PubMed

Affiliation: Electronics and Telecommunications Research Institute (ETRI), 218 Gajeongno, Yuseong-Gu, Daejeon 305-700, Korea. zinsig.kim@gmail.com

ABSTRACT
This report presents biotin-functionalized semiconducting polymers that are based on fluorene and bithiophene co-polymers (F8T2). Also presented is the application of these polymers to an organic thin film transistor used as a biosensor. The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2. Their properties as an organic semiconductor were tested using an organic thin film transistor (OTFT) and were found to show typical p-type semiconductor curves. The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors. Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA.

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Changes of the characteristics of OTFT by detection of sensing materials. (a) Typical plot of drain current ID versus gate voltage VG between 0 and 40 V for biotinylated F8T2 TFTs. (b) On/Off-curve of the organic semiconductor field effect transistor (organic FET) before and after treatment with BSA or avidin.
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f4-sensors-12-11238: Changes of the characteristics of OTFT by detection of sensing materials. (a) Typical plot of drain current ID versus gate voltage VG between 0 and 40 V for biotinylated F8T2 TFTs. (b) On/Off-curve of the organic semiconductor field effect transistor (organic FET) before and after treatment with BSA or avidin.

Mentions: The biotin functional group interacts extremely strongly with specific proteins, for example, avidin or streptavidin, but has almost no interaction with a standard protein, for example, BSA. The biotin-avidin combination is widely applied in the field of bioactive material detection and the applications of their combination are already published [24]. The weak interaction of biotin-BSA combination caused a slight decrease of the drain current and the conductivity of the sensing devices, but the strong interaction of the biotin-avidin combination caused a remarkable decrease in the drain current and also the conductivity of the sensing devices (Figure 4). In our experiments, three kinds of test devices were prepared. One of them was used as a reference for a blank test. The other two were used for testing BSA- or avidin-solution. All three of these devices were treated with 365 nm UV light for 10 min. under an air atmosphere, before the treatment with test-solution. The first one of them was treated with only DI water after UV O3 treatment, which is indicated as “UV O3 10 min” in Figure 4(a). The second one of them was treated with BSA test-solution after UV O3 treatment, which is indicated as “UV O3 10 min-BSA” in Figure 4(a). The third one of them was treated with avidin test-solution after UV O3 treatment, which is indicated as “UV O3 10 min-Avidin” in Figure 4(a). After treatment with three kinds of test solution, the OTFT properties of all three devices were measured. The first device, which was treated with only DI water, showed higher conductivity than the other two devices (“UV O3 10 min”) in Figure 4(a). The second device, which was treated with BSA test solution, showed a 2 order scale decrease in conductivity relative to the first one (“UV O3 10 min-BSA”) in Figure 4(a). The third device, which was treated with avidin test solution, showed a four order scale decrease in conductivity relative to the first one (“UV O3 10 min-Avidin”) in Figure 4(a). As Figure 4(a) shows, the conductivity of the device treated with avidin-solution decreased two orders more than that of the device treated with BSA-solution. Nevertheless, the conductivity of these two devices decreased below that of the device treated with DI-water. The difference of the drain current between avidin-treated and non-treated devices was much more significant than that between the BSA-treated and non-treated devices. After the exposure of OTFT devices to avidin solution, the decrease of the drain current and also the conductivity were so intense that the devices indicated no more OTFT properties, which meant a disappearance of semiconductor properties of biotinylated F8T2 (Figure 4(b)). In comparison to this result, the device treated with BSA-solution indicated the typical OTFT properties after exposure to the BSA-solution. These results indicate that the conductivity of the device treated with the BSA-solution decreased, but the semiconductor properties remained unchanged. The loss of the semiconductor properties of the biotinylated F8T2 can be explained by the shortening of the conjugation length of the carbon-carbon bond in biotinylated F8T2 polymer backbone, due to the strong interaction between biotin and avidin. The biotinylated F8T2 polymer semiconductor seemed to be useful for OTFTs and may be applied to developing an OTFT biosensor or FET for biosensor (BioFET).


Biotin-functionalized semiconducting polymer in an organic field effect transistor and application as a biosensor.

Kim ZS, Lim SC, Kim SH, Yang YS, Hwang DH - Sensors (Basel) (2012)

Changes of the characteristics of OTFT by detection of sensing materials. (a) Typical plot of drain current ID versus gate voltage VG between 0 and 40 V for biotinylated F8T2 TFTs. (b) On/Off-curve of the organic semiconductor field effect transistor (organic FET) before and after treatment with BSA or avidin.
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Related In: Results  -  Collection

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f4-sensors-12-11238: Changes of the characteristics of OTFT by detection of sensing materials. (a) Typical plot of drain current ID versus gate voltage VG between 0 and 40 V for biotinylated F8T2 TFTs. (b) On/Off-curve of the organic semiconductor field effect transistor (organic FET) before and after treatment with BSA or avidin.
Mentions: The biotin functional group interacts extremely strongly with specific proteins, for example, avidin or streptavidin, but has almost no interaction with a standard protein, for example, BSA. The biotin-avidin combination is widely applied in the field of bioactive material detection and the applications of their combination are already published [24]. The weak interaction of biotin-BSA combination caused a slight decrease of the drain current and the conductivity of the sensing devices, but the strong interaction of the biotin-avidin combination caused a remarkable decrease in the drain current and also the conductivity of the sensing devices (Figure 4). In our experiments, three kinds of test devices were prepared. One of them was used as a reference for a blank test. The other two were used for testing BSA- or avidin-solution. All three of these devices were treated with 365 nm UV light for 10 min. under an air atmosphere, before the treatment with test-solution. The first one of them was treated with only DI water after UV O3 treatment, which is indicated as “UV O3 10 min” in Figure 4(a). The second one of them was treated with BSA test-solution after UV O3 treatment, which is indicated as “UV O3 10 min-BSA” in Figure 4(a). The third one of them was treated with avidin test-solution after UV O3 treatment, which is indicated as “UV O3 10 min-Avidin” in Figure 4(a). After treatment with three kinds of test solution, the OTFT properties of all three devices were measured. The first device, which was treated with only DI water, showed higher conductivity than the other two devices (“UV O3 10 min”) in Figure 4(a). The second device, which was treated with BSA test solution, showed a 2 order scale decrease in conductivity relative to the first one (“UV O3 10 min-BSA”) in Figure 4(a). The third device, which was treated with avidin test solution, showed a four order scale decrease in conductivity relative to the first one (“UV O3 10 min-Avidin”) in Figure 4(a). As Figure 4(a) shows, the conductivity of the device treated with avidin-solution decreased two orders more than that of the device treated with BSA-solution. Nevertheless, the conductivity of these two devices decreased below that of the device treated with DI-water. The difference of the drain current between avidin-treated and non-treated devices was much more significant than that between the BSA-treated and non-treated devices. After the exposure of OTFT devices to avidin solution, the decrease of the drain current and also the conductivity were so intense that the devices indicated no more OTFT properties, which meant a disappearance of semiconductor properties of biotinylated F8T2 (Figure 4(b)). In comparison to this result, the device treated with BSA-solution indicated the typical OTFT properties after exposure to the BSA-solution. These results indicate that the conductivity of the device treated with the BSA-solution decreased, but the semiconductor properties remained unchanged. The loss of the semiconductor properties of the biotinylated F8T2 can be explained by the shortening of the conjugation length of the carbon-carbon bond in biotinylated F8T2 polymer backbone, due to the strong interaction between biotin and avidin. The biotinylated F8T2 polymer semiconductor seemed to be useful for OTFTs and may be applied to developing an OTFT biosensor or FET for biosensor (BioFET).

Bottom Line: The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2.The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors.Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA.

View Article: PubMed Central - PubMed

Affiliation: Electronics and Telecommunications Research Institute (ETRI), 218 Gajeongno, Yuseong-Gu, Daejeon 305-700, Korea. zinsig.kim@gmail.com

ABSTRACT
This report presents biotin-functionalized semiconducting polymers that are based on fluorene and bithiophene co-polymers (F8T2). Also presented is the application of these polymers to an organic thin film transistor used as a biosensor. The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2. Their properties as an organic semiconductor were tested using an organic thin film transistor (OTFT) and were found to show typical p-type semiconductor curves. The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors. Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA.

Show MeSH