Ultrasensitive Dopamine Detection with Graphene Aptasensor Multitransistor Arrays

Abstract

Dopamine is a neurotransmitter with critical roles in the human brain and body, and abnormal dopamine levels underlie brain disorders such as Parkinson's Disease, Alzheimer's Disease, and substance addiction. Herein, we present a novel high-throughput biosensor based on graphene multitransistor arrays (gMTAs) functionalized with a selective aptamer for robust ultrasensitive dopamine detection. The miniaturized biosensor integrates multiple electrolyte-gated graphene field-effect transistors (EG-gFETs) in an array configuration, fabricated by high-yield reproducible and scalable methodologies optimized at the wafer level. With these gMTA aptasensors, we reliably detected ultra-low dopamine concentrations in physiological buffers, including undiluted phosphate-buffered saline (PBS), artificial cerebral spinal fluid (aCSF), and high ionic strength complex biological samples. We report a record limit-of-detection (LOD) of 1 aM (10^-18) for dopamine in both PBS, and dopamine-depleted brain homogenate samples spiked with dopamine. The gMTAs also display wide sensing ranges across all media, up to 100 uM (10^-8), with a 22 mV/decade peak sensitivity in aCSF. Furthermore, we show that the gMTAs can detect minimal changes in dopamine concentrations in small working volume biological CSF samples obtained from a mouse model of Parkinson's Disease.

SARS-CoV-2 multi-variant rapid detector based on graphene transistor functionalized with an engineered dimeric ACE2 receptor

“…However, this basic scenario is valid for simple systems tested like ions, while in the case of bigger molecules like glucose [31] , [56] , nucleic acids [57] , [58] , or proteins [59] , [60] , this model shows some inconsistencies. Indeed, the direction of the CNP change may be affected by several factors, such as Debye length, pH of the solution, environment, and spatial-dynamical complexity of the bioreceptor-target interaction, which involves several characteristics such as the orientation of the bioreceptor and bioreceptor-target binding mode [22] , [61] . Nevertheless, the shift of the CNP, before and after the addition of the analyte, is a reporter of binding [22] .…”

“…We report also that, for a limited number of gFETs, the direction of the CNP shift is toward lower voltages. This is not so surprising since the sensing response of a gFET is influenced by different parameters, such as the total number of adsorbed bioreceptors, their orientation on the graphene surface [22] , [61] , [66] , the net charges and subsequent surrounding presence of anions and/or cations [22] , [67] and the Debye Length [22] , [68] . All these factors could lead in some cases to have the CNP shift in a different direction than expected (Figure S15A, B and C).…”

“…In this scenario, it is therefore conceivable that these few differences in the direction of the Dirac point shift could be explained by the presence of different conformations of ACE2-Fc, as seen in the MD simulations, which can reorient the bioreceptor charge closer to or farther away from the FET channel, changing the surface potential thus altering the doping state of graphene in its initial value (Figure S15A, B and C). There are several examples in which the bioreceptor structural plasticity and therefore conformational changes play a crucial role in the detection of biomolecules and signals analysis in biosensing experiments [61] , [69] , [70] , [71] , [72] , [73] , however, this mechanism will need to be further investigated.…”

Implantable Aptamer-Graphene Microtransistors for Real-Time Monitoring of Neurochemical Release in Vivo

“…Compared with In 2 O 3 used in this study, graphene has a much higher carrier mobility than that of In 2 O 3 (17.8 ± 1.8 cm 2 /V·s). , In addition, graphene offers many attractive properties for in vivo biosensing applications, such as biocompatibility and chemical inertness. − The graphene microtransistor is a three-terminal electronic device in which graphene is used as a channel material between the source and drain terminals . While graphene microtransistors have been used for electrophysiological recordings in vivo − and the detection of dopamine in vitro , , there is no study to date on the real-time monitoring of dopamine release in vivo using implantable aptamer modified graphene microtransistors.…”

Características do sono e qualidade de vida de adultos praticantes de atividade física

“…Isso porque parecem mais preocupadas com a saúde, buscando os serviços para o tratamento de doenças na fase inicial, enquanto os homens estão habituados a não se preocuparem com a sua saúde e estão mais expostos às causas externas, que reduzem os indicadores de longevidade 91,92 93 ; no estudo da UnATI PUC em Goiás-Brasil, com 75% 94 . Em São Mamede-PB, a autora evidenciou 93,33% também de mulheres, em um estudo 95 , e outros dois estudos, com 75% e 84,50%, respectivamente 96,97 Os participantes estavam na faixa etária acima dos 50 anos, e a faixa etária que ainda continua trabalhando é de 50 a 59 anos de idade. A aposentadoria é expressiva, entre os participantes.…”