Nanomaterials and biomaterials in electrochemical arrays for protein detection

Abstract

Nanomaterials and biomaterials are important components of new electrochemical arrays designed for sensitive detection of proteins in biological fluids. Such multiplexed protein arrays are predicted to have an important future in personalized medical diagnostics, especially for cancer and heart disease. Sandwich immunoassays for proteins benefit greatly in sensitivity from the use of nanostructured sensor surfaces and multilabeled detection strategies involving nano- or microparticles. In these assays, capture agents such as antibodies or aptamers are attached to sensor surfaces in the array. Target proteins with large binding constants for the affinity agents are captured from liquid samples with high efficiency, either on the sensors or on magnetic bioconjugate particles decorated with many copies of labels and antibodies. After target proteins are captured on the sensor surfaces, the labels are detected by electrochemical techniques. This feature article begins with an overview of the recent history of nanoparticles in electrochemical protein sensors, then moves on to specific examples from our own laboratories. We discuss fabrication of nanostructured sensors and arrays with the aim of multiplexed detection as well as reusability. Following this, we describe systems that integrate particle-based protein sensing with microfluidics for multiplexed protein detection. We end with predictions on the diagnostic future of protein detection.

Use of Redox Probes for Characterization of Layer-by-Layer Gold Nanoparticle-Modified Screen-Printed Carbon Electrodes

“…1 Nanomaterials have been widely used for the preparation of energy storage and conversion devices [2][3][4][5] as well as sensors, biosensors, and bioelectronics. 1,[5][6][7][8] Such applications have largely been driven by the advantageous properties of nanomaterials, such as their large surface areas, electrocatalytic capabilities, and/or abilities to facilitate electron transport between bulk materials and electrochemically active biological materials.…”

“…6 LbL-constructed nanostructured electrodes have found use in the preparation of supercapacitors 4,5 and proton-exchange membrane fuel cells (PEMFCs) 4 as well as chemical sensors and biosensors. 1,[6][7][8] Sensors and biosensors prepared by LbL methods often employ ionic polymers like poly(diallyldimethylammonium chloride) (PDDA) and/or polystyrene sulfonate (PSS) to facilitate adsorption of metal, semiconductor, or carbon-based nanoparticles (e.g., nanospheres, nanorods, nanotubes or graphene sheets) typically onto a bulk carbon or gold electrode. In addition to conventional disk-shaped glassy carbon, pyrolytic carbon, and gold electrodes, screen-printed electrodes have also found wide use as platforms for LbL-based sensors and biosensors.…”

“…When employed as platforms for sensing and biosensing, such electrodes reportedly exhibit improved electrochemical properties (e.g., enhanced response and/or superior electron-transfer kinetics over bare SPCEs). 7,8,[16][17][18] One benefit provided by nanoparticles that is typically asserted as important in rationalizing the augmented response of nanomaterial-modified SPCEs over bare SPCEs is the increase in electroactive surface area provided by the inclusion of nanomaterials on the electrode surface. 7,8,[16][17][18] The electroactive surface area, A, is often determined (in cm 2 ) through voltammetric studies of common redox probes by employing the Randles-Ševčík equation (at 25…”

Low-Cost Microfluidic Arrays for Protein-Based Cancer Diagnostics Using ECL Detection

“…ECL detection has been adapted in microfluidic immunoarrays to detect proteins utilizing silica beads with containing Ru(bpy) 3 2+ dye and coated with antibodies for detection. 4,22 The process used in our laboratory is shown in Fig. 2.…”

“…4 Rather simple ideas from nanotechnology and materials science have provided new opportunities to design and fabricate such devices. Approaches include soft-polymer template molding, precision cutting of polymer sheets, and nano-and microwell printing.…”