Electro-Engineered Polymeric Films for the Development of Sensitive Aptasensors for Prostate Cancer Marker Detection

Abstract

We report the development of a simple surface chemistry strategy for the construction of sensitive aptasensors on a polypyrrole (PPy)-polyethylene glycol (PEG) platform in order to provide enhanced anti-fouling properties. We report the covalent modification of a PPy film formed on a gold electrode by PEG molecules, without prior chemical functionalization of the pyrrole monomer. This process was mediated by electro-oxidation of amine groups present on the one of the PEG's end chains. Poly-histidine modified aptamers were immobilized to this surface via a Nα,Nα-Bis(carboxymethyl)-L-lysine ANTA/Cu 2+ redox complex covalently attached to the PPy-PEG adduct. The fabricated aptasensor was then utilized for the detection of αmethylacyl-CoA racemase (AMACR; P504S), an emerging biomarker for prostate cancer. Protein/aptamer interactions were monitored through variation of the copper redox signal, using the square wave voltammetry (SWV) technique. We demonstrate that the PPy-PEG-ANTA/Cu 2+ hybrid material is characterized by enhanced anti-fouling properties and sensitivity. The aptasensor was able to detect AMACR down to 5 fM both in buffer and spiked human plasma with a limit of detection (LOD) of 0.15 fM and 1.4 fM, respectively. The developed aptasensor can be generalized for use with any type of aptamer-based sensor. Recently, several research groups have tried to develop biosensors for AMACR detection. 8 In 2014, Yang et al. 9 first reported an anti-AMACR DNA aptamer (AMC51) with a dissociation constant of 44 nM and demonstrated a fluorescent enzyme-linked aptamer assay (ELAA) for AMACR detection, which featured a low detection limit of 0.44 nM. A DNA aptamer is a ligand binding single stranded DNA that binds to its target with high affinity and specificity by undergoing conformational changes. 10 Compared to antibodies, aptamers have several advantages including ease of synthesis and modification, chemical stability, small size, and low immunogenicity. These features make aptamers promising alternatives to antibodies for biosensor research. 3,11 In this work, we present the development of an electrochemical AMACR aptasensor based on electro-patterned polyethylene glycol (PEG) on polypyrrole (PPy) film. PEG as a polymer has been widely used to develop biosensors, due to its anti-fouling properties. 12 However, it becomes difficult to employ PEG in an electrochemical platform due to its electri

Flexible Printed Organic Electrochemical Transistors for the Detection of Uric Acid in Artificial Wound Exudate

“…Gelatin A and B are natural hydrogels derived from porcine skin; they are biocompatible and provide a robust environment for enzymes. [29,[51][52][53][54] The use of gelatin represents a valuable functionalization strategy for woundmonitoring biosensors, as they were already used for wound patches and scaffolds. [55][56][57] The gelatin A layer is permeable to UA and therefore allows it to reach Uricase, which catalyzes its oxidation to 5-hydroxyisourate that finally spontaneously converts into allantoin (Figure 2A).…”

An aptasensor for the detection of Mycobacterium tuberculosis secreted immunogenic protein MPT64 in clinical samples towards tuberculosis detection

“…The long linker used in this study was based on a hydrophilic ethylene glycol (CH 2 CH 2 O) 6 group which enabled the aptamer sequence to protrude from the modified electrode surface. Ethylene glycol was also used to eliminate any steric hindrance associated with the binding process as well as to reduce a non-specific interaction 26,27 .…”

Phase‐Regulated Sensing Mechanism of MoS2 Based Nanohybrids toward Point‐of‐Care Prostate Cancer Diagnosis

“…AMACR level in blood from patients with prostate cancer was in sub × 10 −6 m (ng µL −1 ) range. [ 46–48 ] Thus, the evaluated LOD and a measurement capability of AMACR over a concentration range from pg µL −1 to ng µL −1 demonstrates a great capability and practibility for differentiating prostate cancer patients from healthy individuals.…”