Publications by authors named "Roland Zengerle"

We introduce a novel approach for highly parallel droplet dispensing with precise control over the droplet parameters such as droplet volume, droplet velocity, etc. This approach facilitates the fabrication of homogeneous and precise thin layers with uniform coverage on defined small areas (e.g.

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In this article, we explore multi-material additive manufacturing (MMAM) for conductive trace printing using molten metal microdroplets on polymer substrates to enhance digital signal transmission. Investigating microdroplet spread informs design rules for adjacent trace printing. We studied the effects of print distance on trace morphology and resolution, noting that printing distance showed almost no change in the printed trace pitch.

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The technology to jet print metal lines with precise shape fidelity on diverse substrates is gaining higher interest across multiple research fields. It finds applications in additively manufactured flexible electronics, environmentally friendly and sustainable electronics, sensor devices for medical applications, and fabricating electrodes for solar cells. This paper provides an experimental investigation to deepen insights into the non-contact printing of solder lines using StarJet technology, eliminating the need for surface activation, substrate heating, curing, or post-processing.

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Creating model systems that replicate in vivo tissues is crucial for understanding complex biological pathways like drug response and disease progression. Three-dimensional (3D) in vitro models, especially multicellular spheroids (MCSs), offer valuable insights into physiological processes. However, generating MCSs at scale with consistent properties and efficiently recovering them pose challenges.

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3D cell culture is becoming increasingly important for mimicking physiological tissue structures in areas such as drug discovery and personalized medicine. To enable reproducibility on a large scale, automation technologies for standardized handling are still a challenge. Here, a novel method for fully automated size classification and handling of cell aggregates like spheroids and organoids is presented.

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C-reactive protein is a well-studied host response biomarker, whose diagnostic performance depends on its accurate classification into concentration zones defined by clinical scenario-specific cutoff values. We validated a newly developed, bead-based, bound-free phase detection immunoassay (BFPD-IA) versus a commercial CE-IVD enzyme-linked immunosorbent assay (ELISA) kit and a commercial CE-IVD immunoturbidimetric assay (ITA) kit. The latter was performed on a fully automated DPC Konelab 60i clinical analyzer used in routine diagnosis.

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Article Synopsis
  • * A new two-stage diagnostic workflow has been developed, allowing for rapid testing and drug susceptibility analysis from a single sputum sample, completed in just three days.
  • * The first stage utilizes automated qPCR to detect TB and resistance to key antibiotics, followed by targeted next generation sequencing (tNGS) for complete resistance profiling when necessary.
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Highly effective targeted therapies are available to treat noncommunicable chronic inflammatory skin diseases. In contrast, the exact diagnosis of noncommunicable chronic inflammatory skin diseases is complicated by its complex pathogenesis and clinical and histological overlap. Particularly, the differential diagnosis of psoriasis and eczema can be challenging in some cases, and molecular diagnostic tools need to be developed to support a gold standard diagnosis.

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Spheroids, organoids, or cell-laden droplets are often used as building blocks for bioprinting, but so far little is known about the spatio-temporal cellular interactions subsequent to printing. We used a drop-on-demand bioprinting approach to study the biological interactions of such building blocks in dimensions of micrometers. Highly-density droplets (approximately 700 cells in 10 nL) of multiple cell types were patterned in a 3D hydrogel matrix with a precision of up to 70 μm.

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cfDNA is an emerging biomarker with promising uses for the monitoring of cancer or infectious disease diagnostics. This work demonstrates a new concept for an automated cfDNA extraction with nanobeads as the solid phase in a centrifugal microfluidic LabDisk. By using a combination of centrifugal and magnetic forces, we retain the nanobeads in one incubation chamber while sequentially adding, incubating and removing the sample and pre-stored buffers for extraction.

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Centrifugal microfluidics enables fully automated molecular diagnostics at the point-of-need. However, the integration of solid-phase nucleic acid extraction remains a challenge. Under this scope, we developed the magnetophoresis under continuous rotation for magnetic bead-based nucleic acid extraction.

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Accurately measuring flow rates is a key requirement in many medical applications such as infusion and drug delivery systems. A major drawback of current systems is the low resolution of the sensors in the low flow rate regime. In this article, we present a method based on Holographic PIV/PTV that has been used for the first time to measure flow rates in the range of a few nL/min.

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Three-dimensional (3D) cell agglomerates, such as microtissues, organoids, and spheroids, become increasingly relevant in biomedicine. They can provide models that recapitulate functions of the original tissue in the body and have applications in cancer research. For example, they are widely used in organ-on-chip systems.

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In this paper, we present the ImmunoDisk, a fully automated sample-to-answer centrifugal microfluidic cartridge, integrating a heterogeneous, wash-free, magnetic- and fluorescent bead-based immunoassay (bound-free phase detection immunoassay/BFPD-IA). The BFPD-IA allows the implementation of a simple fluidic structure, where the assay incubation, bead separation and detection are performed in the same chamber. The system was characterized using a C-reactive protein (CRP) competitive immunoassay.

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We used arrays of bioprinted renal epithelial cell spheroids for toxicity testing with cisplatin. The concentration-dependent cell death rate was determined using a lactate dehydrogenase assay. Bioprinted spheroids showed enhanced sensitivity to the treatment in comparison to monolayers of the same cell type.

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3D-bioprinting is a promising technology applicable in areas such as regenerative medicine or organ model development. Various 3D-bioprinting technologies and systems have been developed and are partly commercially available. Here, we present the construction and characterization of an open-source low-cost 3D-bioprinter that allows the alternated microextrusion of hydrogel and fused deposition modeling (FDM) of thermoplastic filaments.

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We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence 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 emulsification, our method partitioned the sample into 210 pL (73 µm in diameter) droplets for bacterial encapsulation followed by permeabilization, hybridization, and signal detection.

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The generation of artificial human tissue by 3D-bioprinting has expanded significantly as a clinically relevant research topic in recent years. However, to produce a complex and viable tissue, in-depth biological understanding and advanced printing techniques are required with a high number of process parameters. Here, we systematically evaluate the process parameters relevant for a hybrid bioprinting process based on fused-deposition modeling (FDM) of thermoplastic material and microextrusion of a cell-laden hydrogel.

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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 overcome these limitations, we developed a paper-based open microfluidic platform for electrophoretic protein separation and subsequent transfer to protein-binding membranes for immunoprobing.

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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 ( and ) in colorectal carcinoma. Standardized parameters for the digital assay were derived using design of experiments.

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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 microfluidic platform (OralDisk) compatible with chair-side use that enables analysis of non-invasively collected whole saliva samples and molecular-based detection of ten bacteria: seven periodontitis-associated (, , , , , , ) and three caries-associated (oral , , ).

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Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in childhood. Minimal residual disease (MRD) monitoring is an important prognostic factor for ALL treatment response and patient stratification. MRD monitoring uses personalized real-time PCR to measure the amount of cancer cells among normal cells.

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Article Synopsis
  • Next generation sequencing is transitioning from research use to routine diagnostics, requiring high-quality processes in sample prep, library prep, sequencing, and bioinformatics to ensure accurate results.
  • The study introduces an automated library preparation method for whole genome sequencing using centrifugal microfluidics, which allows two samples to be processed simultaneously and cuts reagent volumes by 40% and sample usage by 60%.
  • The system's effectiveness was demonstrated with two types of samples, achieving an impressive 99.8% coverage for bacterial DNA and 78.2% coverage for human DNA, showcasing its potential for accurate sequencing in smaller laboratories.
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Despite the widespread application of point-of-care lateral flow tests, the viscosity dependence of these assay results remains a significant challenge. Here, we employ centrifugal microfluidic flow control through the nitrocellulose membrane of the strip to eliminate the viscosity bias. The key feature is the balancing of the sample flow into the cassette of the lateral flow test with the air flow out of the cassette.

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We report on the development of a microfluidic multiplexing technology for highly parallelized sample analysis via quantitative polymerase chain reaction (PCR) in an array of 96 nanoliter-scale microcavities made from silicon. This PCR array technology features fully automatable aliquoting microfluidics, a robust sample compartmentalization up to temperatures of 95 °C, and an application-specific prestorage of reagents within the 25 nl microcavities. The here presented hybrid silicon-polymer microfluidic chip allows both a rapid thermal cycling of the liquid compartments and a real-time fluorescence read-out for a tracking of the individual amplification reactions taking place inside the microcavities.

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