Ultrasensitive Field‐Effect Biosensors Enabled by the Unique Electronic Properties of Graphene

Zhang, Xiaoyan; Jing, Qiushi; Shen, Ao; Schneider, Grégory F.; Kireev, Dmitry; Zhang, Zhengjun; Fu, Wangyang

doi:10.1002/smll.201902820

Cited by 80 publications

(87 citation statements)

References 247 publications

(617 reference statements)

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“…Next, a blocking buffer comprising a wash step with 0.05% Tween-20 was applied to remove unbound biomolecules from the graphene surface as much as possible, before incubating the functionalized channel with ETA to block the remaining unreacted N -hydroxy succinimidyl (NHS) ester linkers on the channel surface. Specificity of the biosensor was also assured by means of a previously tested method of additional biosensor passivation performed with ethanolamine and Tween-20 [39,40]. This last functionalization step yielded an average Vdirac of 240 ± 40 mV (Figure 2, blue line).…”

Section: Resultsmentioning

confidence: 98%

Graphene-Based Biosensor for Early Detection of Iron Deficiency

Oshin

Kireev

Hlukhova

et al. 2020

Sensors

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Iron deficiency (ID) is the most prevalent and severe nutritional disorder globally and is the leading cause of iron deficiency anemia (IDA). IDA often progresses subtly symptomatic in children, whereas prolonged deficiency may permanently impair development. Early detection and frequent screening are, therefore, essential to avoid the consequences of IDA. In order to reduce the production cost and complexities involved in building advanced ID sensors, the devices were fabricated using a home-built patterning procedure that was developed and used for this work instead of lithography, which allows for fast prototyping of dimensions. In this article, we report the development of graphene-based field-effect transistors (GFETs) functionalized with anti-ferritin antibodies through a linker molecule (1-pyrenebutanoic acid, succinimidyl ester), to facilitate specific conjugation with ferritin antigen. The resulting biosensors feature an unprecedented ferritin detection limit of 10 fM, indicating a tremendous potential for non-invasive (e.g., saliva) ferritin detection.

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Section: Resultsmentioning

confidence: 98%

Graphene-Based Biosensor for Early Detection of Iron Deficiency

Oshin

Kireev

Hlukhova

et al. 2020

Sensors

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“…Gate leakage has been a very common phenomenon in liquid-gated GFETs and is primarily caused by the electrochemical redox reaction at the graphene/liquid interface resulting in an increased current flow which negatively impacts the sensing performances of the sensor. Though passivation of the exposed electrodes can reduce the leakage current, carbon clusters and photoresist residues during the wet transfer of CVD-graphene can act as a source of carbon leading to redox current during the device operation [ 24 , 25 ]. Among the three gate materials tested, Ag/AgCl resulted in the lowest gate leakage.…”

Section: Resultsmentioning

confidence: 99%

Detection of an IL-6 Biomarker Using a GFET Platform Developed with a Facile Organic Solvent-Free Aptamer Immobilization Approach

Khan

Song

2021

Sensors

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Aptamer-immobilized graphene field-effect transistors (GFETs) have become a well-known detection platform in the field of biosensing with various biomarkers such as proteins, bacteria, virus, as well as chemicals. A conventional aptamer immobilization technique on graphene involves a two-step crosslinking process. In the first step, a pyrene derivative is anchored onto the surface of graphene and, in the second step, an amine-terminated aptamer is crosslinked to the pyrene backbone with EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide) chemistry. However, this process often requires the use of organic solvents such as dimethyl formamide (DMF) or dimethyl sulfoxide (DMSO) which are typically polar aprotic solvents and hence dissolves both polar and nonpolar compounds. The use of such solvents can be especially problematic in the fabrication of lab-on-a-chip or point-of-care diagnostic platforms as they can attack vulnerable materials such as polymers, passivation layers and microfluidic tubing leading to device damage and fluid leakage. To remedy such challenges, in this work, we demonstrate the use of pyrene-tagged DNA aptamers (PTDA) for performing a one-step aptamer immobilization technique to implement a GFET-based biosensor for the detection of Interleukin-6 (IL-6) protein biomarker. In this approach, the aptamer terminal is pre-tagged with a pyrene group which becomes soluble in aqueous solution. This obviates the need for using organic solvents, thereby enhancing the device integrity. In addition, an external electric field is applied during the functionalization step to increase the efficiency of aptamer immobilization and hence improved coverage and density. The results from this work could potentially open up new avenues for the use of GFET-based BioMEMS platforms by broadening the choice of materials used for device fabrication and integration.

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“…which depends on the width W and length L of the graphene, μ the mobility of charge carriers and C g the gate capacitance. 148 Transconductances for holes and electrons are not necessarily the same, in which case the transfer curve is asymmetrical. Transfer curves can be obtained using any of the three gate electrode configurations described in section 2.2 and illustrated in Fig.…”

Section: Transfer Curvesmentioning

confidence: 99%