Andreas Offenhäusser

Photoresponsive properties of ultrathin silicon nanowires

Publisher: AIP Publishing

Date: 08-12-2014

DOI: 10.1063/1.4904089

Abstract: Functional silicon nanowires (SiNWs) are promising building blocks in the design of highly sensitive photodetectors and bio-chemical sensors. We systematically investigate the photoresponse properties of ultrathin SiNWs (20 nm) fabricated using a size-reduction method based on e-beam lithography and tetramethylammonium hydroxide wet-etching. The high-quality SiNWs were able to detect light from the UV to the visible range with excellent sensitivity (∼1 pW/array), good time response, and high photoresponsivity (R ∼ 2.5 × 104 A/W). Improvement of the ultrathin SiNWs' photoresponse has been observed in comparison to 40 nm counter-part nanowires. These properties are attributable to the predominance surface-effect due to the high surface-to-volume ratio of ultrathin SiNWs. Long-term measurements at different temperatures in both the forward and reverse bias directions demonstrated the stability and reliability of the fabricated device. By sensitizing the fabricated SiNW arrays with cadmium telluride quantum dots (QDs), hybrid QD SiNW devices displayed an improvement in photocurrent response under UV light, while preserving their performance in the visible light range. The fast, stable, and high photoresponse of these hybrid nanostructures is promising towards the development of optoelectronic and photovoltaic devices.

Fabrication of locally thinned down silicon nanowires

Publisher: Royal Society of Chemistry (RSC)

Date: 2014

DOI: 10.1039/C4TC00046C

Abstract: A new top-down fabrication process is described to prepare at the wafer-scale locally thinned down silicon nanowire field-effect devices.

Membrane on a Chip: A Functional Tethered Lipid Bilayer Membrane on Silicon Oxide Surfaces

Publisher: Elsevier BV

Date: 09-2005

DOI: 10.1529/BIOPHYSJ.105.061374

CMOS-Compatible Silicon Nanowire Field-Effect Transistor Biosensor: Technology Development toward Commercialization

Publisher: MDPI AG

Date: 11-05-2018

DOI: 10.3390/MA11050785

Wafer-scale fabrication of ultra-thin silicon nanowire devices

Publisher: IEEE

Date: 08-2013

DOI: 10.1109/NANO.2013.6720826

Complementary Metal Oxide Semiconductor Compatible Silicon Nanowires-on-a-Chip: Fabrication and Preclinical Validation for the Detection of a Cancer Prognostic Protein Marker in Serum

Publisher: American Chemical Society (ACS)

Date: 15-01-2015

DOI: 10.1021/AC503374J

Abstract: An integrated translational biosensing technology based on arrays of silicon nanowire field-effect transistors (SiNW FETs) is described and has been preclinically validated for the ultrasensitive detection of the cancer biomarker ALCAM in serum. High-quality SiNW arrays have been rationally designed toward their implementation as molecular biosensors. The FET sensing platform has been fabricated using a complementary metal oxide semiconductor (CMOS)-compatible process. Reliable and reproducible electrical performance has been demonstrated via electrical characterization using a custom-designed portable readout device. Using this platform, the cancer prognostic marker ALCAM could be detected in serum with a detection limit of 15.5 pg/mL. Importantly, the detection could be completed in less than 30 min and span a wide dynamic detection range (∼10(5)). The SiNW-on-a-chip biosensing technology paves the way to the translational clinical application of FET in the detection of cancer protein markers.

Silicon Nanowires Field Effect Transistors: A Comparative Sensing Performance between Electrical Impedance and Potentiometric Measurement Paradigms.

Publisher: American Chemical Society (ACS)

Date: 04-09-2019

DOI: 10.1021/ACS.ANALCHEM.9B03559

Abstract: Potentiometric sensors based on silicon nanowire field effect transistors (SiNW FETs) typically display exquisite sensitivities, but their bioanalytical implementation is limited due to the need for stringent measurement conditions and high-precision readout units. An alternative operation principle where SiNW FETs are operated in a frequency-domain electrical impedimetric approach is promising. However, to date only limited data is available in regard to the sensing performance and translational relevance of this novel approach in comparison to the standard charge detection paradigm. We demonstrate the feasibility of conducting electrical impedimetric FET measurements with a portable unit for the ultrasensitive detection of cancer biomarkers in biospecimens. Compared to standard potentiometric measurements, electrical impedimetric FET measurements yielded significant improvements in biosensing performances, including the limit of detection, sensing resolution, and dynamic range.

Electrochemical current rectification–a novel signal amplification strategy for highly sensitive and selective aptamer-based biosensor

Publisher: Elsevier BV

Date: 04-2015

DOI: 10.1016/J.BIOS.2014.10.057

Abstract: Electrochemical aptamer-based (E-AB) sensors represent an emerging class of recently developed sensors. However, numerous of these sensors are limited by a low surface density of electrode-bound redox-oligonucleotides which are used as probe. Here we propose to use the concept of electrochemical current rectification (ECR) for the enhancement of the redox signal of E-AB sensors. Commonly, the probe-DNA performs a change in conformation during target binding and enables a nonrecurring charge transfer between redox-tag and electrode. In our system, the redox-tag of the probe-DNA is continuously replenished by solution-phase redox molecules. A unidirectional electron transfer from electrode via surface-linked redox-tag to the solution-phase redox molecules arises that efficiently lifies the current response. Using this robust and straight-forward strategy, the developed sensor showed a substantial signal lification and consequently improved sensitivity with a calculated detection limit of 114nM for ATP, which was improved by one order of magnitude compared with the lification-free detection and superior to other previous detection results using enzymes or nanomaterials-based signal lification. To the best of our knowledge, this is the first demonstration of an aptamer-based electrochemical biosensor involving electrochemical rectification, which can be presumably transferred to other biomedical sensor systems.

Toward Intraoperative Detection of Disseminated Tumor Cells in Lymph Nodes with Silicon Nanowire Field Effect Transistors

Publisher: American Chemical Society (ACS)

Date: 11-02-2016

DOI: 10.1021/ACSNANO.5B07136

Abstract: Within an hour, as little as one disseminated tumor cell (DTC) per lymph node can be quantitatively detected using an intraoperative biosensing platform based on silicon nanowire field-effect transistors (SiNW FET). It is also demonstrated that the integrated biosensing platform is able to detect the presence of circulating tumor cells (CTCs) in the blood of colorectal cancer patients. The presence of DTCs in lymph nodes and CTCs in peripheral blood is highly significant as it is strongly associated with poor patient prognosis. The SiNW FET sensing platform out-performed in both sensitivity and rapidity not only the current standard method based on pathological examination of tissue sections but also the emerging clinical gold standard based on molecular assays. The possibility to achieve accurate and highly sensitive analysis of the presence of DTCs in the lymphatics within the surgery time frame has the potential to spare cancer patients from an unnecessary secondary surgery, leading to reduced patient morbidity, improving their psychological wellbeing and reducing time spent in hospital. This study demonstrates the potential of nanoscale field-effect technology in clinical cancer diagnostics.

Eberhard Karls Universitat Tubingen

Location: Germany

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Universitat Ulm

Location: Germany

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Riken Nokagaku Sogo Kenkyu Center

Location: Japan

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Robert Bosch GmbH

Location: Germany

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Forschungszentrum Jülich

Location: Germany

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Max-Planck-Institut Für Polymerforschung

Location: Germany

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Discovery Projects - Grant ID: DP170100170

Start Date: 03-2017

End Date: 12-2020

Amount: $371,000.00

Funder: Australian Research Council