Electrical biochip technology?a tool for microarrays and continuous monitoring

Abstract

Based on electrical biochips made in Si-technology cost effective portable devices have been constructed for field applications and point of care diagnosis. These miniaturized amperometric biosensor devices enable the evaluation of biomolecular interactions by measuring the redox recycling of ELISA products, as well as the electrical monitoring of metabolites. The highly sensitive redox recycling is facilitated by interdigitated ultramicroelectrodes of high spatial resolution. The application of these electrical biochips as DNA microarrays for the molecular diagnosis of viral infections demonstrates the measurement procedure. Self-assembling of capture oligonucleotides via thiol-gold coupling has been used to construct the DNA interface on-chip. Another application for this electrical detection principle is continuous measuring with bead-based biosensors. Here, paramagnetic nanoparticles are used as carriers of the bioanalytical interface in ELISA format. A Si-micromachined glucose sensor for continuous monitoring in interstitial fluid ex vivo shows the flexibility of the electrical platform. Here the novel approach is a pore membrane in micrometer-dimensions acting as a diffusion barrier. The electrochemical detection takes place in a cavity containing glucose oxidase and a Pt-electrode surface. The common hydrogen peroxide detection, together with Si technology, enable precise differential measurements using a second cavity.

Ultrasensitive detection of a protein by optical trapping in a photonic‐plasmonic microcavity

“…Protein detection with plasmon-coupled microcavity biosensor [5,6], optical sensors such as Raman spectroscopy [7][8][9][10][11], plasmon resonance [12] and emerging Whispering Gallery Mode (WGM) [13][14][15][16][17][18] sensors have been utilized for detecting biomolecules at mg-ng/ml sensitivity levels. WGM biosensing offers a particularly sensitive approach to quantify the mass loading of biomolecules on the resonator surface with ultimate sensitivity estimated on the single molecule level [19,20].…”

Top-Down Processed SOI Nanowire Devices for Biomedical Applications

“…In particular biosensors based on nanoelectronic devices promise a variety of applications in biomedicine for instance for future 'point-of-care' diagnostic tools (9)(10)(11)(12). In order to miniaturize the tools and to develop cheap and direct electronic 'hand-held' devices, most of the time a direct and label-free detection of the analytes is required (13,14).…”

Local detection of enzymatic ion generation with polycrystalline silicon interdigitated electrodes and its application to biosensing

“…They can be easily conjugated to biomolecules via different cross linkers and well known chemical procedures, and the reactions they catalyze can be detected either optically 6,7 or electrochemically. [8][9][10][11] In this letter, a biosensing principle is presented and tested. It consists in the generation of ions by an enzyme and the local detection of them by polycrystalline silicon interdigitated electrodes.…”