Graphene-based materials for biotransistor application
A biomimetic cell membrane bioelectronic transistor consisting of a supported phospholipid bilayer atop chemical vapor deposition (CVD) graphene or solution processed reduced graphene oxide on titanium dioxide (TiO2) has been successfully demonstrated for biosensing application. For the first time,...
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| Format: | Thesis |
| Language: | English |
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2019
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| Online Access: | https://hdl.handle.net/10356/89327 http://hdl.handle.net/10220/47698 |
| _version_ | 1826120667058143232 |
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| author | Ng, Wei-Beng |
| author2 | Cho Nam-Joon |
| author_facet | Cho Nam-Joon Ng, Wei-Beng |
| author_sort | Ng, Wei-Beng |
| collection | NTU |
| description | A biomimetic cell membrane bioelectronic transistor consisting of a supported phospholipid bilayer atop chemical vapor deposition (CVD) graphene or solution processed reduced graphene oxide on titanium dioxide (TiO2) has been successfully demonstrated for biosensing application. For the first time, a unique bonding interaction between titanium and carbon atom on graphene oxide has been experimentally identified by X-ray Photoelectron Spectroscopy (XPS). The covalent interaction acts as a strong surface anchorage in facilitating uniform adhesion and near to ideal surface coverage of spin coated graphene oxide on titanium bearing substrate using the in-situ solid-liquid phase exfoliation method. The liquid gated Reduced Graphene Oxide (RGO) biotransistor is sensitive to environmental changes in ionic strength of liquid environment by shift in electrical output signals at a sensitivity level of ~0.030mA per millimolar at gate bias VG=-8V and 0.035mA per millimolar at drain bias VD=1V. Incorporation of a phospholipid membrane atop the RGO transformed the sensing transistor to a bioelectronic transistor capable of sensing attached biomolecules on functionalized lipid/RGO surface acting as pseudo gate bias which modulated the electrical signals output. Supported neutral and charged lipid membranes on RGO at active source-drain region were formed by solvent assisted lipid bilayer (SALB) formation. A modulation of transistor conductance induced by gate charges were observed by the measurement of transistor drain current. Based on the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/RGO biotransistor platform, a functional supported lipid bilayer (SLB) was demonstrated using biotin-streptavidin binding event. The quantification of biotin composition with respect to transistor drain current modulation was monitored which showed a linear relationship between the percentage of changes in drain current versus the percentage of biotin composition in the complex SLB. For instance, a 12% change in drain current was measured for a 1wt % biotinylated DOPC lipid complex membrane upon streptavidin binding. The results illustrated the potential of using lipid bilayer as an efficient biofunctionalization tool on graphene oxide as a highly versatile and sensitive biosensing platform for a variety of receptor-ligand binding events. |
| first_indexed | 2024-10-01T05:20:12Z |
| format | Thesis |
| id | ntu-10356/89327 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:20:12Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | ntu-10356/893272020-11-01T04:53:50Z Graphene-based materials for biotransistor application Ng, Wei-Beng Cho Nam-Joon Interdisciplinary Graduate School (IGS) DRNTU::Engineering::Bioengineering A biomimetic cell membrane bioelectronic transistor consisting of a supported phospholipid bilayer atop chemical vapor deposition (CVD) graphene or solution processed reduced graphene oxide on titanium dioxide (TiO2) has been successfully demonstrated for biosensing application. For the first time, a unique bonding interaction between titanium and carbon atom on graphene oxide has been experimentally identified by X-ray Photoelectron Spectroscopy (XPS). The covalent interaction acts as a strong surface anchorage in facilitating uniform adhesion and near to ideal surface coverage of spin coated graphene oxide on titanium bearing substrate using the in-situ solid-liquid phase exfoliation method. The liquid gated Reduced Graphene Oxide (RGO) biotransistor is sensitive to environmental changes in ionic strength of liquid environment by shift in electrical output signals at a sensitivity level of ~0.030mA per millimolar at gate bias VG=-8V and 0.035mA per millimolar at drain bias VD=1V. Incorporation of a phospholipid membrane atop the RGO transformed the sensing transistor to a bioelectronic transistor capable of sensing attached biomolecules on functionalized lipid/RGO surface acting as pseudo gate bias which modulated the electrical signals output. Supported neutral and charged lipid membranes on RGO at active source-drain region were formed by solvent assisted lipid bilayer (SALB) formation. A modulation of transistor conductance induced by gate charges were observed by the measurement of transistor drain current. Based on the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/RGO biotransistor platform, a functional supported lipid bilayer (SLB) was demonstrated using biotin-streptavidin binding event. The quantification of biotin composition with respect to transistor drain current modulation was monitored which showed a linear relationship between the percentage of changes in drain current versus the percentage of biotin composition in the complex SLB. For instance, a 12% change in drain current was measured for a 1wt % biotinylated DOPC lipid complex membrane upon streptavidin binding. The results illustrated the potential of using lipid bilayer as an efficient biofunctionalization tool on graphene oxide as a highly versatile and sensitive biosensing platform for a variety of receptor-ligand binding events. Doctor of Philosophy 2019-02-19T01:17:33Z 2019-12-06T17:22:58Z 2019-02-19T01:17:33Z 2019-12-06T17:22:58Z 2018 Thesis Ng, W. -B. (2018). Graphene-based materials for biotransistor application. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/89327 http://hdl.handle.net/10220/47698 10.32657/10220/47698 en 135 p. application/pdf |
| spellingShingle | DRNTU::Engineering::Bioengineering Ng, Wei-Beng Graphene-based materials for biotransistor application |
| title | Graphene-based materials for biotransistor application |
| title_full | Graphene-based materials for biotransistor application |
| title_fullStr | Graphene-based materials for biotransistor application |
| title_full_unstemmed | Graphene-based materials for biotransistor application |
| title_short | Graphene-based materials for biotransistor application |
| title_sort | graphene based materials for biotransistor application |
| topic | DRNTU::Engineering::Bioengineering |
| url | https://hdl.handle.net/10356/89327 http://hdl.handle.net/10220/47698 |
| work_keys_str_mv | AT ngweibeng graphenebasedmaterialsforbiotransistorapplication |