Felix von Stetten

Felix von Stetten
Hahn-Schickard · Institut für Mikroanalysesysteme Freiburg

Apl. Prof. Dr.

About

236
Publications
54,958
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7,849
Citations
Introduction
Apl. Prof. Dr. Felix von Stetten is Executive Board Member at the Hahn-Schickard-Institut für Mikroanalysesysteme Freiburg, a non-profit research organisation supporting the industry in the development of new in-vitro diagnostic products. He is also lecturer in "biotechnology for engineers" at the Department of Microsystems Engineering - IMTEK, University of Freiburg.

Publications

Publications (236)
Article
Full-text available
RNA interference (RNAi) is a powerful therapeutic approach for messenger RNA (mRNA) level regulation in human cells. RNAi can be triggered by small interfering RNAs (siRNAs) which are delivered by non-viral carriers, e.g., dendriplexes. siRNA quantification inside carriers is essential in drug delivery system development. However, current siRNA mea...
Preprint
Single-cell RNA sequencing (scRNA-seq) can unmask transcriptional heterogeneity facilitating the detection of rare subpopulations at unprecedented resolution. In response to challenges related to coverage and quantity of transcriptome analysis, the lack of unbiased and quantitative validation methods hampers further improvements. Digital PCR (dPCR)...
Article
Full-text available
We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence in situ hybridization (FISH) assay in droplets. The method offers minimal manual workload by only requiring mixing of the sample with reagents and loading it into a microfluidic cartridge. By centrifugal microfluidic step emulsific...
Article
Protein electrophoresis and immunoblotting are indispensable analytical tools for the characterization of proteins and posttranslational modifications in complex sample matrices. Owing to the lack of automation, commonly employed slab‐gel systems suffer from high time demand, significant sample/antibody consumption and limited reproducibility. To o...
Article
Full-text available
The detection of multiple biomolecule classes in one go is highly desirable for a wide variety of areas, and in particular for point-of-care diagnostics. For example, wound infections are a major problem for patient’s health and cause huge efforts in our healthcare system. In this regard, monitoring infected wounds through simultaneous detection of...
Article
Full-text available
There is an increasing demand for optimization-free multiplex assays to rapidly establish comprehensive target panels for cancer monitoring by liquid biopsy. We present the mediator probe (MP) PCR for the quantification of the seven most frequent point mutations and corresponding wild types (KRAS and BRAF) in colorectal carcinoma. Standardized para...
Conference Paper
Inkjet-printing of nanoparticle inks allows the integration of electrodes directly into 2.5D structures, like microfluidic chambers. Sensing applications can additionally benefit from the nanoporous morphology of the printed electrodes. The presented results demonstrate that the high effective surface of the porous electrode is suitable for functio...
Article
Full-text available
Periodontitis and dental caries are two major bacterially induced, non-communicable diseases that cause the deterioration of oral health, with implications in patients' general health. Early, precise diagnosis and personalized monitoring are essential for the efficient prevention and management of these diseases. Here, we present a disk-shaped micr...
Article
Full-text available
Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in childhood. Minimal residual disease (MRD) monitoring is an important prognostic factor for treatment response and patient stratification. It uses personalized real-time PCR to measure the amount of cancer cells among normal cells. Due to clonal tumor evolution or secondary rearra...
Article
Multiplexing of analyses is essential to reduce sample and reagent consumption in applications with large target panels. In applications such as cancer diagnostics, the required degree of multiplexing often exceeds the number of available fluorescence channels in polymerase chain reaction (PCR) devices. The combination of photobleaching-sensitive a...
Article
Full-text available
Sample-in-answer-out" type integrated diagnostic devices have been widely recognized as the ultimate solution to simplify testing across healthcare systems. Such systems are equipped with advanced fluidic, mechanical, chemical, biological, and electronic components to handle patient samples without any manual steps therefore have the potential to a...
Cover Page
Full-text available
In article number 2010388, Can Dincer and co‐workers present integrated “sample‐to‐answer” diagnostic platforms including wearable, handheld, and tabletop devices for non‐invasive monitoring. Factors influencing the translation of these devices from the fundamental research phase through the commercialization and into our daily life are discussed v...
Article
Full-text available
The rapid detection of pathogens in infected wounds can significantly improve the clinical outcome. Wound exudate, which can be collected in a non-invasive way, offers an attractive sample material for the detection of pathogens at the point-of-care (POC). Here, we report the development of a nucleic acid lateral flow immunoassay for direct detecti...
Article
Full-text available
This paper presents a universal point-of-care system for fully automated quantification of human T-cell lymphotropic virus type 1 (HTLV-1) proviral load, including genomic RNA, based on digital reverse RNA transcription and c-DNA amplification by MD LAMP (mediator displacement loop-mediated isothermal amplification). A disposable microfluidic LabDi...
Article
We implement dual-volume centrifugal step emulsification on a single chip to extend the dynamic range of digital assays. Compared to published single-volume approaches, the range between the lower detection limit (LDL) and the upper limit of quantification (ULQ) increases by two orders of magnitude. In comparison to existing multivolume approaches,...
Article
Full-text available
We present the centrifugal microfluidic implementation of a four-plex digital droplet polymerase chain reaction (ddPCR). The platform features 12 identical ddPCR units on a LabDisk cartridge, each capable of generating droplets with a diameter of 82.7 ± 9 µm. By investigating different oil–surfactant concentrations, we identified a robust process f...
Article
Periodontitis and dental caries are two major bacterially induced, non-communicable diseases that cause the deterioration of oral health, with implications in patients’ general health. Early, precise diagnosis and personalized monitoring are essential for the efficient prevention and management of these diseases. Here, we present a disk-shaped micr...
Article
Full-text available
We present an automated point-of-care testing (POCT) system for rapid detection of species- and resistance markers in methicillin-resistant Staphylococcus aureus (MRSA) at the level of single cells, directly from nasal swab samples. Our novel system allows clear differentiation between MRSA, methicillin-sensitive S. aureus (MSSA) and methicillin-re...
Article
Full-text available
We present a versatile tool for the generation of monodisperse water-in-fluorinated-oil droplets in standard reaction tubes by centrifugal step emulsification. The microfluidic cartridge is designed as an insert into a standard 2 mL reaction tube and can be processed in standard laboratory centrifuges. It allows for droplet generation and subsequen...
Article
Full-text available
Inkjet technology as a maskless, direct-writing technology offers the potential for structured deposition of functional materials for the realization of electrodes for, e.g., sensing applications. In this work, electrodes were realized by inkjet-printing of commercial nanoparticle gold ink on planar substrates and, for the first time, onto the 2.5D...
Article
Yaws, a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue, manifests as ulcerative skin lesions. Nucleic acid amplification tests, like loop-mediated isothermal amplification (LAMP), are versatile tools to distinguish yaws from infections that cause similar skin lesions, primarily Haemophilus ducreyi. We deve...
Article
Driven by the vision of robust and portable, yet sensitive DNA detection systems for point-of-need applications, the development of electrochemical DNA sensing principles has been of high interest. Many different principles have been developed and these are regularly reviewed. However, the maturity of electrochemical principles and their ability to...
Article
Correction for ‘Review: a comprehensive summary of a decade development of the recombinase polymerase amplification’ by Jia Li et al. , Analyst , 2019, 144 , 31–67.
Article
Full-text available
This comprehensive review provides a systematic classification and a comparative evaluation of current sequence-specific detection methods for LAMP.
Article
Full-text available
The alarming dynamics of antibiotic-resistant infections calls for the development of rapid and point-of-care (POC) antibiotic susceptibility testing (AST) methods. Here, we demonstrated the first completely stand-alone microfluidic system that allowed the execution of digital enumeration of bacteria and digital antibiograms without any specialized...
Article
Effective mosquito monitoring relies on the accurate identification and characterization of the target population. Since this process requires specialist knowledge and equipment that is not widely available, automated field-deployable systems are highly desirable. We present a centrifugal microfluidic cartridge, the VectorDisk, which integrates Taq...
Article
We demonstrate that buoyancy in centrifugal step emulsification enables substantially higher generation rates of monodis-perse droplets compared to pressure driven set-ups. Step emulsification in general can produce droplets in comparatively simple systems (only one moving liquid) with a low CV of < 5% in droplet diameter and a minimum dead volume....
Article
We introduce a new concept for centrifugal microfluidics that enables fully automated serial dilution generation without any additional means besides temperature control. Key feature is time-independent, serial valving of mixing chambers by fill-level-coupled temperature change rate (FLC-TCR) actuated valving. The automated dilution is realized und...
Article
Most patients with acute infectious diseases develop fever, which is frequently a reason to visit health facilities in resource-limited settings. The symptomatic overlap between febrile diseases impedes their diagnosis on clinical grounds. Therefore, the World Health Organization promotes an integrated management of febrile illness. Along this line...
Article
Full-text available
In this study we optimised the fluorescence signal generation of contact quenched universal reporter oligonucleotides. These are used as secondary probes in real-time Mediator Probe PCR to detect the sequence-specific cleavage of label-free primary mediator probes. Since the fluorescence signal generation of a universal reporter is not influenced b...
Article
A variety of real-time detection techniques for LAMP based on the change in fluorescence intensity during DNA amplification enable simultaneous detection of multiple targets. However these techniques depend on fluorogenic probes containing target-specific sequences. That complicates the adaption to different targets leading to time-consuming assay...
Article
Centrifugal microfluidics enables the rapid execution of complex blood sample analyses in a fully automated manner at the point of care. However, during blood sample addition, the cartridge is at rest and centrifugal forces are not present to allocate the sample in a controlled way. We present a versatile approach for the user-friendly, well-contro...
Article
Full-text available
Nucleic acid amplification has permeated every field in the life sciences since the introduction of the classic polymerase chain reaction (PCR) method in 1983. Yet, despite its fundamental reach, PCR has been constrained within the walls of a laboratory, due to its requirement for a sophisticated thermocycling machine, limiting external application...
Article
The combination of digital amplification and centrifugal microfluidics can enable quantitative and fast diagnostics at the point of care (PoC). The new unit operation of centrifugal step emulsification allows high throughput droplet generation. Different methods for digital nucleic acid analysis, including PCR, recombinase polymerase amplification...
Poster
Centrifugal microfluidics offer the possibility to rapidly analyze blood samples at the point-of-care (POC). However, during blood sample addition the cartridge is at rest and centrifugal forces cannot be used to allocate the sample in a controlled manner. This may represent a risk to the user’s safety, as well as the test result. We present a vers...
Chapter
A smartphone-based colorimetric reader (SBCR), comprising a Samsung Galaxy SIII mini, a gadget (iPAD mini, iPAD4, or iPhone 5s) and a custom-made dark hood and base holder assembly, is used for human C-reactive protein (CRP) immunoassay. A 96-well microtiter plate (MTP) is positioned on the gadget’s screensaver to provide white light-based bottom i...
Article
Automated and robust separation of 14 μl of plasma from 40 μl of whole blood at a purity of 99.81% ± 0.11% within 43 s is demonstrated for the hematocrit range of 20%–60% in a centrifugal microfluidic polymer disk. At high rotational frequency, red blood cells (RBCs) within whole blood are concentrated in a radial outer RBC collection chamber. Simu...
Article
We present new unit operations for valving and switching in centrifugal microfluidics that are actuated by a temperature change rate (TCR) and controlled by the rotational frequency. Implementation is realized simply by introducing a comparatively large fluidic resistance to an air vent of a fluidic structure downstream of a siphon channel. During...
Conference Paper
Full-text available
We present the LabCard, a new centrifugal microfluidic approach for simultaneous processing of multiple test carriers by arranging them in the vertical plane. As a proof-of-concept, we fluidically integrated an assay for isothermal nucleic acid analyses of respiratory pathogens with the microfluidic network comprising unit operations and processing...
Article
Full-text available
Mediator probe (MP) PCR is a real-time PCR approach that uses standardized universal fluorogenic reporter oligonucleotides (UR) in conjunction with label-free sequence-specific probes. To enable multiplex real-time MP PCR, we designed a set of five optimized URs with different fluorescent labels. Performance of the optimized URs was verified in mul...
Conference Paper
Introduction Point-of-care tests (POCT) enable fast diagnosis of infectious diseases especially in resource-poor settings, where they are typically operated by minimally-trained personnel and replace missing clinical infrastructure [1]. Problems regarding user- and patient safety and the system’s performance can arise during the sample intake due t...
Article
The last decade has witnessed tremendous advances in employing microfluidic solutions enabling Continuous Processing and Monitoring of Biological Samples (CPMBS), which is an essential requirement for the control of bio-processes. The microfluidic systems are superior to the traditional inline sensors due to their ability to implement complex analy...
Article
We present a centrifugal microfluidic LabDisk for protein structure analysis via small-angle X-ray scattering (SAXS) on synchrotron beamlines. One LabDisk prepares 120 different measurement conditions, grouped into six dilution matrices. Each dilution matrix: (1) features automatic generation of 20 different measurement conditions from three input...
Article
Full-text available
Primer and probe sequence designs are among the most critical input factors in real-time polymerase chain reaction (PCR) assay optimization. In this study, we present the use of statistical design of experiments (DOE) approach as a general guideline for probe optimization and more specifically focus on design optimization of label-free hydrolysis p...
Article
Full-text available
Digital nucleic acid amplification methods are a growing research field that allows for absolute quantification of DNA making the need of standard curves redundant. However, most existing digital amplification systems require specialized laboratory devices and costly investments. The required disposable cartridges are device specific and not interc...
Article
Multiplexing in Polymerase Chain Reaction (PCR) is a technique widely used to save cost, sample material and to increase sensitivity compared to distributing a sample to several singleplex reactions. One of the most common methods to detect the different amplification products is the use of fluorogenic probes that emit at different wavelengths (col...
Chapter
The SP-based devices with associated smart applications are being used for personalized general healthcare monitoring, notably analyses of blood glucose, weight, heart rate, etc., a major driving force in the creation of new enterprises such as iHealth LLC, Runtastic, AliveCor, GENTAG and Holomic LLC. The success of SP-based devices and smart appli...
Article
Full-text available
Global healthcare systems are struggling with the enormous burden associated with infectious diseases, as well as the incessant rise of antimicrobial resistance. In order to adequately address these issues, there is an urgent need for rapid and accurate infectious disease diagnostics. The H2020 project DIAGORAS aims at diagnosing oral and respirato...
Article
Full-text available
Air-pressure-mediated, pneumatic siphon valves employ temporary storage and subsequent release of pneumatic energy, exclusively controlled by rotation of the disk. Implementation is easy, and robust valves can be integrated in a monolithic way at minimum additional costs. However, so far, pneumatic siphon valving requires deceleration from high to...
Article
Existing systems for digital droplet PCR (ddPCR) either suffer from low integration or are difficult to introduce to mass fabrication. Here we present an integrated system that is compatible to mass fabrication and combines emulsification, PCR, and fluorescence readout in a single chamber within a disposable cartridge (disk). Droplets are generated...
Article
Portable point-of-care devices for pathogen detection require easy, minimal and user-friendly handling steps and need to have the same diagnostic performance compared to centralized laboratories. In this work we present a fully automated sample-to-answer detection of influenza A H3N2 virus in a centrifugal LabDisk with complete prestorage of reagen...
Article
We present batch-mode mixing for centrifugal microfluidics operated at fixed rotational frequency. Gas is generated by the disk integrated decomposition of hydrogen peroxide (H2O2) to liquid water (H2O) and gaseous oxygen (O2) and inserted into a mixing chamber. There, bubbles are formed that ascent through the liquid in the artificial gravity fiel...
Article
We introduce microfluidic automation of geometrically multiplexed real-time PCR to off-the-shelf Rotor-Gene Q thermocyclers (RGQ, QIAGEN GmbH, Hilden, Germany). For centrifugal fluid control the RGQ provides low and constant rotation of 400 rpm, only. Compatibility to this very limited flexibility of centrifugal actuation is achieved by using therm...
Article
Full-text available
Easy-to-use point-of-care (POC) tests provide rapid diagnostic results near the patient, enabling fast decision-making in patient management. However, the implementation of automated molecular diagnostic POC tests still faces technical challenges. We demonstrate a highly sensitive POC platform for automated molecular diagnostics of neonatal sepsis...
Conference Paper
We demonstrate for the first time the highly precise and fully automated manufacturing of tubular-shaped composite-foil pouches for the pre-storage of liquid reagents in lab-on-a-chip disposables. Those stick-packs are miniaturized and easy to handle packages and enable: i) the protection of reagents from external influences (e.g. irradiation, vapo...
Article
Microparticles are widely used as solid phase for affinity-based separation. Here, we introduce a new method for automated handling of microparticles in centrifugal microfluidics that is not restricted by the particle size and requires neither auxiliary means such as magnets nor coating of microfluidic structures. All steps are initiated and contro...
Article
Full-text available
The high throughput preparation of emulsions with high internal volume fractions is important for many different applications, e.g., drug delivery. However, most emulsification techniques reach only low internal volume fractions and need stable flow rates that are often difficult to control. Here, we present a centrifugal high throughput step emuls...