In-Situ Integration of 3D C-MEMS Microelectrodes with Bipolar Exfoliated Graphene for Label-Free Electrochemical Cancer Biomarkers Aptasensor

Abstract

The electrochemical label-free aptamer-based biosensors (also known as aptasensors) are highly suitable for point-of-care applications. The well-established C-MEMS (carbon microelectromechanical systems) platforms have distinguishing features which are highly suitable for biosensing applications such as low background noise, high capacitance, high stability when exposed to different physical/chemical treatments, biocompatibility, and good electrical conductivity. This study investigates the integration of bipolar exfoliated (BPE) reduced graphene oxide (rGO) with 3D C-MEMS microelectrodes for developing PDGF-BB (platelet-derived growth factor-BB) label-free aptasensors. A simple setup has been used for exfoliation, reduction, and deposition of rGO on the 3D C-MEMS microelectrodes based on the principle of bipolar electrochemistry of graphite in deionized water. The electrochemical bipolar exfoliation of rGO resolves the drawbacks of commonly applied methods for synthesis and deposition of rGO, such as requiring complicated and costly processes, excessive use of harsh chemicals, and complex subsequent deposition procedures. The PDGF-BB affinity aptamers were covalently immobilized by binding amino-tag terminated aptamers and rGO surfaces. The turn-off sensing strategy was implemented by measuring the areal capacitance from CV plots. The aptasensor showed a wide linear range of 1 pM–10 nM, high sensitivity of 3.09 mF cm−2 Logc−1 (unit of c, pM), and a low detection limit of 0.75 pM. This study demonstrated the successful and novel in-situ deposition of BPE-rGO on 3D C-MEMS microelectrodes. Considering the BPE technique’s simplicity and efficiency, along with the high potential of C-MEMS technology, this novel procedure is highly promising for developing high-performance graphene-based viable lab-on-chip and point-of-care cancer diagnosis technologies.

Role of Nanomaterials in the Fabrication of bioNEMS/MEMS for Biomedical Applications and towards Pioneering Food Waste Utilisation

“…This has been observed in several studies that developed label-free C-MEMS aptasensors through the introduction of carbon-rich materials (e.g., reduced graphene oxide, SU-8 photoresist) for early detection of cancer biomarkers. In both studies, electrochemical characterisation revealed a comparable linear range of detection [114,115].…”

“…Carbon-NEMS/C-MEMS involves the patterning of carbon-based materials followed by pyrolysis in an oxygen-free environment. According to Forouzanfar, et al [114], C-NEMS/MEMS approaches offer facile fabrication of electrochemical-based sensors equipped with tailored glassy-like carbon structures (e.g., three-dimensional micropillar, microchannel, microarray) and active surfaces for functionalization due to the high presence of carboxyl groups (-COOH). This has been observed in several studies that developed label-free C-MEMS aptasensors through the introduction of carbon-rich materials (e.g., reduced graphene oxide, SU-8 photoresist) for early detection of cancer biomarkers.…”

Advancement in Biosensor Technologies of 2D MaterialIntegrated with Cellulose—Physical Properties

“…Moreover, electrochemical biosensors utilizing graphene and other 2D materials have shown great potential for detecting biomarkers associated with hematological malignancies like leukemia, lymphoma, and multiple myeloma. These biosensors offer a wide linear range, a low detection limit, high sensitivity, excellent selectivity, and cost-effectiveness [ 40 ].…”