Andreas OffenhäusserForschungszentrum Jülich · Institute for Biological Information Processing (IBI)
Andreas Offenhäusser
Univ.Professor; Dr. rer. nat. habil.
About
597
Publications
80,768
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14,223
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Introduction
Additional affiliations
October 2002 - present
June 2001 - March 2020
July 1994 - May 2001
Max-Planck-Institut für Polymerforschung
Education
December 2000 - December 2000
January 1986 - December 1989
October 1979 - December 1985
Publications
Publications (597)
Ischemia and reperfusion states are studied in a network of cardiomyocytes as a part of real‐state conditions of heart injuries and inflammations, specifically myocardial infractions. Arrays of graphene field‐effect transistors (GFETs) fabricated in this work are used for extracellular recordings of ischemia states of cardiac cells during the exter...
The development of organic artificial synapses that exhibit biomimicry features also may enable a more seamless integration of neuroelectronic devices in the nervous system, allowing artificial neuromodulation to be perceived as natural behavior by neuronal cells. Nevertheless, the capability to interact with both electroactive and non‐electroactiv...
In this published publication [...]
In this work we employ a surface plasmon microscope to quantize the birefringence of hemozoin in blood. We correlate the hemozoin concentration with the observed refractive index and birefringence.
Sensitive magnetic nucleic acid (NA) detection via frequency mixing magnetic detection (FMMD) requires amplified NA samples for which a reliable temperature control is necessary. The feasibility of recombinase polymerase amplification (RPA) was studied within a newly integrated temperature-controlled sensor unit of a mobile FMMD based setup. It has...
Conventional electrochemical sensors use voltammetric and amperometric methods with external power supply and modulation systems, which hinder the flexibility and application of the sensors. To avoid the use of an external power system and to minimize the number of electrochemical cell components, a self-powered electrochemical sensor (SPES) for hy...
In this work, we study the refractive-index profile of co-cultured myelinated dorsal root ganglion neurons from embryonic rats in-vitro with the developed surface plasmon microscope. This provides a platform to quantize the neuronal characteristics in a label-free manner.
Keywords: myelination, refractive index, surface plasmon, label-free, DRG,...
Plasmodium falciparum and Plasmodium vivax species are associated for malarial infections primarily in south-African and south-Asian sub-continents respectively. In this work we extract the refractive index of whole blood (WB) infected with Plasmodium falciparum or Plasmodium vivax species. Surface plasmon microscopy is used for the extraction of r...
In this work, we characterize the refractive index profile of a single bilayer for native lipid and MS mimicking lipid with surface plasmon microscopy
Planar microelectrode arrays (MEAs) for – in vitro or in vivo – neuronal signal recordings lack the spatial resolution and sufficient signal‐to‐noise ratio (SNR) required for a detailed understanding of neural network function and synaptic plasticity. To overcome these limitations, a highly customizable three‐dimensional (3D) printing process is us...
Due to the limitations of conventional Brucella detection methods, including safety concerns, long incubation times, and limited specificity, the development of a rapid, selective, and accurate technique for the early detection of Brucella in livestock animals is crucial to prevent the spread of the associated disease. In the present study, we intr...
Many neurodegenerative diseases such as Alzheimer's report the presence of various amyloid species of various concentration. In this work we used focused surface plasmon microscopy as a label-free technique to distinguish the various species of Ab-40 in-vitro. The aggregation kinetics of various amyloid species can be easily distinguished from the...
Optogenetics is a powerful approach in neuroscience research. However, other tissues of the body may benefit from controlled ion currents and neuroscience may benefit from more precise optogenetic expression. The present work constructs three subcellularly‐targeted optogenetic actuators based on the channelrhodopsin ChR2‐XXL, utilizing 5, 10, or 15...
Mechanical stimulation is a promising means to non-invasively excite and modulate neuronal networks with a high spatial resolution. Despite the thorough characterization of the initiation mechanism, whether or how mechanical responses disperse into non-target areas remains to be discovered. Our in vitro study demonstrates that a single-neuron defor...
The interaction between neurons and nanostructured substrates is a topic of increasing interest due to the possibility of manipulating individual cells on substrates on length scales of protein size. Moreover, patterns of biochemical ligand cues are known to play a crucial role in neuronal network guidance. A comprehensive study of cell adhesion to...
Accurate determination of serotonin (ST) provides insight into neurological processes and enables applications in clinical diagnostics of brain diseases. Herein, we present an electrochemical aptasensor based on truncated DNA aptamers and a polyethylene glycol (PEG) molecule-functionalized sensing interface for highly sensitive and selective ST det...
The combination of electrophysiology and neuroimaging methods allows the simultaneous measurement of electrical activity signals with calcium dynamics from single neurons to neuronal networks across distinct brain regions in vivo. While traditional electrophysiological techniques are limited by photo-induced artefacts and optical occlusion for neur...
Electrochemical and optical platforms are commonly employed in designing biosensors. However, one signal readout can easily lead to inaccuracies due to the effect of nonstandard test procedures, different operators, and experimental environments. We have developed a dual-signal protocol that combined two transducer principles in one aptamer-based b...
Neural interfaces are evolving at a rapid pace owing to advances in material science and fabrication, reduced cost of scalable complementary metal oxide semiconductor (CMOS) technologies, and highly interdisciplinary teams of researchers and engineers that span a large range from basic to applied and clinical sciences. This study outlines currently...
The healing of neuronal injuries is still an unachieved goal. Medicine-based therapies can only extend the survival of patients, but not finally lead to a healing process. Currently, a variety of stem cell-based tissue engineering developments are the subject of many research projects to bridge this gap. As yet, neuronal differentiation of induced...
Frequency mixing magnetic detection (FMMD) has been widely used in magnetic immunoassay measurement techniques. It can also be used to characterize and distinguish different magnetic nanoparticle (MNP) types according to their magnetic cores size. In a previous work, a method for resolving ambiguities in determination of the core size distribution...
The combination of graphene and silicon in hybrid electronic devices has attracted increasing attention over the last decade. Here, a unique technology of graphene‐on‐silicon heterostructures as solution‐gated transistors for bioelectronics applications is presented. The proposed graphene‐on‐silicon field‐effect transistors (GoSFETs) are fabricated...
Prussian blue nanoparticles (PB NPs) stabilized with surface capping agents as functional mimics of major antioxidant enzymes are attracting attention for use in reactions mediated by reactive oxygen species. However, influence of a stabilizing agent or interface on the enzyme-like properties of the nanomaterial remains unclear. In this study, we i...
In this work, a novel sandwich-type electrochemical immunosensor was developed for the quantitative detection of the carcinoembryonic antigen, an important tumor marker in clinical tests. The capture antibodies were immobilized on the surface of a gold disk electrode, while detection antibodies were attached to redox-tagged single-walled carbon nan...
Frequency mixing magnetic detection (FMMD) has been explored for its applications in fields of magnetic biosensing, multiplex detection of magnetic nanoparticles (MNP) and the determination of core size distribution of MNP samples. Such applications rely on the application of a static offset magnetic field, which is generated traditionally with an...
We combine in vitro monitoring of cardiomyocyte cell activity using Si nanowire field-effect transistors with fluorescence microscopy to develop a bio-platform that enables us to reveal the effects of pharmacologically active agents on the living cells by tracking the cell calcium content, mitochondrial membrane potential, and cellular electrical s...
Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as “colourization”) of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles...
This study investigates the intrinsic multienzyme-like properties of the non-stabilized nanocrystalline nanoparticles of manganese-doped Prussian blue (Mn-PB) nanozymes and Prussian blue (PB) nanozymes in chemical and electrocatalytic transformations of reactive oxygen species. The effect of manganese doping on the structural, biomimetic, and elect...
Calcium (Ca2+) ions play a pivotal role in physiology and cellular signaling. The intracellular Ca2+ concentration ([Ca2+]i) is about three orders of magnitude lower than the extracellular concentration, resulting in a steep transmembrane concentration gradient. Thus, the spatial and the temporal dynamics of [Ca2+]i are ideally suited to modulate C...
Many pH sensors on the market today have specific limitations, such as the large and fragile construction of glass electrodes, or the complicated manufacturing processes of silicon-based devices including ion-sensitive field-effect transistors (ISFETs). Furthermore, most pH sensors require a stable reference electrode, which is difficult to miniatu...
The further development of neurochips requires high‐density and high‐resolution recordings that also allow neuronal signals to be observed over a long period of time. Expanding fields of network neuroscience and neuromorphic engineering demand the multiparallel and direct estimations of synaptic weights, and the key objective is to construct a devi...
Studies of biochemical liquids require precise determination of their complex permittivity. We developed a microwave characterization technique on the basis of a high-quality whispering-gallery mode (WGM) sapphire resonator with a microfluidic channel filled with the liquid under test. A novel approach allows obtaining the complex permittivity of b...
The combination of graphene with silicon in hybrid devices has attracted attention extensively over the last decade. Most of such devices were proposed for photonics and radiofrequency applications. In this work, we present a unique technology of graphene-on-silicon heterostructures and their properties as solution-gated transistors. The graphene-o...
Despite significant eradication efforts, malaria remains a persistent infectious disease with high mortality due to the lack of efficient point-of-care (PoC) screening solutions required to manage low-density asymptomatic parasitemia. In response, we demonstrate a quantitative electrical biosensor based on system-integrated two-dimensional field-ef...
A novel double-resonant plasmonic substrate for fluorescence amplification in a chip-based apta-immunoassay is herein reported. The amplification mechanism relies on plasmon-enhanced fluorescence (PEF) effect. The substrate consists of an assembly of plasmon-coupled and plasmon-uncoupled gold nanoparticles (AuNPs) immobilized onto a glass slide. Pl...
An electrochemical aptamer-based sensor was developed for glutamate, the major excitatory neurotransmitter in the central nervous system. Determining glutamic acid release and glutamic acid levels is crucial for studying signal transmission and for diagnosing pathological conditions in the brain. Glutamic acid-selective oligonucleotides were isolat...
Chronically implanted neural probes are powerful tools to decode brain activity however, recording population and spiking activity over long periods remains a major challenge. Here, we designed and fabricated flexible intracortical Michigan-style arrays with a shank cross-section per electrode of 250 μm2 utilizing the polymer paryleneC with the goa...
Despite all efforts, malaria is still highly prevalent in tropical and developing countries. The “test, treat and track” policy of the World Health Organization (WHO) demands the development of affordable and highly sensitive malaria tests that discriminate between the two common malaria parasites, Plasmodium falciparum and Plasmodium vivax, to gui...
Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic be...
In this work, we analyze the impact of a chip coating with a self-assembled monolayer (SAM) of (3-aminopropyl)triethoxysilane (APTES) on the electronic and mechanical properties of neuroelectronic interfaces. We show that the large signal transfer, which has been observed for these interfaces, is most likely a consequence of the strong mechanical c...
Recent investigations into cardiac or nervous tissues call for systems that are able to electrically record in 3D as opposed to 2D. Typically, challenging microfabrication steps are required to produce 3D microelectrode arrays capable of recording at the desired position within the tissue of interest. As an alternative, additive manufacturing is be...
Many nano- and microstructured devices capable of promoting neuronal growth and network formation have been previously investigated. In certain cases, topographical cues have been successfully complemented with external bias, by employing electrically conducting scaffolds. However, the use of optical stimulation with topographical cues was rarely a...
To understand the physiology and pathology of electrogenic cells and the corresponding tissue in their full complexity, the quantitative investigation of the transmission of ions as well as the release of chemical signals is important. Organic (semi‐) conducting materials and in particular organic electrochemical transistor are gaining in importanc...
Graphene has numerous potential applications in ultrathin electronics. There an electrode should function in contact with fluids and under mechanical stress; therefore, its stability is specifically of concern. Here, we explored a custom-made quartz crystal microbalance (QCM) sensor covered with wet-transferred large-scale monolayer graphene for in...
Electrochemical sensors that can determine single/multiple analytes remain a key challenge in miniaturized analytical systems and devices. In this study, we present in situ synthesis and modification of gold nanodendrite electrodes to create an electrochemical system for the analysis of hydrogen peroxide. The sensor system consisted of the referenc...
A plasmon-enhanced fluorescence-based antibody-aptamer biosensor — consisting of gold nanoparticles randomly immobilized onto a glass substrate via electrostatic self-assembly — is described for specific detection of proteins in whole blood. Analyte recognition is realized through a sandwich scheme with a capture bioreceptor layer of antibodies — c...
With the fast-shrinking of the transistor dimensions, the low-frequency noise level considerably increases emerging as an important parameter for the design of advanced devices for information technologies. Single-trap phenomena (STP) is a promising approach for the low-frequency noise suppression technique in nanotransistor biosensors by consideri...
The complexity of the extracellular matrix consists of micro‐ and nanoscale structures that influence neuronal development through contact guidance. Substrates with defined topographic cues mimic the complex extracellular environment and can improve the interface between cells and biomedical devices as well as potentially serve as tissue engineerin...
The efficiency of devices for biomedical applications, including tissue engineering and neuronal stimulation, heavily depends on their biocompatibility and performance level. Therefore, it is important to find adequate materials that meet the necessary requirements such as (i) being intrinsically compatible with biological systems, (ii) providing a...
Development of plasmonic biosensors combining reliability and ease of use is still a challenge. Gold nanoparticle arrays made by block copolymer micelle nanolithography (BCMN) stand out for their scalability, cost-effectiveness and tunable plasmonic properties, making them ideal substrates for fluorescence enhancement. Here, we describe a plasmon-e...
Two transducer principles are combined in one aptamer biosensor (aptasensor) by simultaneously performing electrochemical impedance spectroscopy (EIS) and surface plasmon polariton (SPP) detection of a malaria biomarker. A thin gold film perforated with nanohole arrays is modified with small and highly charged aptamer receptors and utilized for the...
The efforts to improve the treatment efficacy in blind patients with retinal degenerative diseases would greatly benefit from retinal activity feedback, which is lacking in current retinal implants. While the door for a bidirectional communication device that stimulates and records intraretinally has been opened by the recent use of silicon-based p...