Publications by authors named "Gielen F"

Background: In vitro expression involves the utilization of the cellular transcription and translation machinery in an acellular context to produce one or more proteins of interest and has found widespread application in synthetic biology and in pharmaceutical biomanufacturing. Most in vitro expression systems available are active at moderate temperatures, but to screen large libraries of natural or artificial genetic diversity for highly thermostable enzymes or enzyme variants, it is instrumental to enable protein synthesis at high temperatures.

Objectives: Develop an in vitro expression system operating at high temperatures compatible with enzymatic assays and with technologies that enable ultrahigh-throughput protein expression in reduced volumes, such as microfluidic water-in-oil (w/o) droplets.

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Objective: Short-term outcomes of deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) were reported for people with drug-resistant focal epilepsy (PwE). Because long-term data are still scarce, the Medtronic Registry for Epilepsy (MORE) evaluated clinical routine application of ANT-DBS.

Methods: In this multicenter registry, PwE with ANT-DBS were followed up for safety, efficacy, and battery longevity.

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The study of dose-response relationships underpins analytical biosciences. Droplet microfluidics platforms can automate the generation of microreactors encapsulating varying concentrations of an assay component, providing datasets across a large chemical space in a single experiment. A classical method consists in varying the flow rate of multiple solutions co-flowing into a single microchannel (producing different volume fractions) before encapsulating the contents into water-in-oil droplets.

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An alarming rise in antimicrobial resistance worldwide has spurred efforts into the search for alternatives to antibiotic treatments. The use of bacteriophages, bacterial viruses harmless to humans, represents a promising approach with potential to treat bacterial infections (phage therapy). Recent advances in microscopy-based single-cell techniques have allowed researchers to develop new quantitative methodologies for assessing the interactions between bacteria and phages, especially the ability of phages to eradicate bacterial pathogen populations and to modulate growth of both commensal and pathogen populations.

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Cancer-associated fibroblasts (CAFs) are a crucial component in the tumor microenvironment influencing cancer progression. Besides shaping the extracellular matrix, these fibroblasts provide signaling factors to facilitate tumor survival and alter tumor behavior. In gastric cancer, one crucial signaling pathway influencing invasion and metastasis is the Wnt/Planar Cell Polarity (PCP) signaling.

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Background And Objectives: The efficacy of deep brain stimulation of the anterior nucleus of the thalamus (ANT DBS) in patients with drug-resistant epilepsy (DRE) was demonstrated in the double-blind Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy randomized controlled trial. The Medtronic Registry for Epilepsy (MORE) aims to understand the safety and longer-term effectiveness of ANT DBS therapy in routine clinical practice.

Methods: MORE is an observational registry collecting prospective and retrospective clinical data.

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Microfluidic water-in-oil emulsion droplets are becoming a mainstay of experimental biology, where they replace the classical test tube. In most applications, such as ultrahigh-throughput directed evolution, the droplet content is identical for all compartmentalized assay reactions. When emulsion droplets are used for kinetics or other functional assays, though, concentration dependencies of initial rates that define Michaelis-Menten parameters are required.

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The movement trajectories of organisms serve as dynamic read-outs of their behaviour and physiology. For microorganisms this can be difficult to resolve due to their small size and fast movement. Here, we devise a novel droplet microfluidics assay to encapsulate single micron-sized algae inside closed arenas, enabling ultralong high-speed tracking of the same cell.

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Objective: Deep Brain Stimulation (DBS) in the Anterior Nucleus of the Thalamus (ANT) has been shown to be a safe and efficacious treatment option for patients with Drug-Resitant focal Epilepsy (DRE). The ANT has been selected frequently in open and controlled studies for bilateral DBS. There is a substantial variability in ANT-DBS outcomes which is not fully understood.

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Since the first reports two decades ago, droplet-based systems have emerged as a compelling tool for microbiological and (bio)chemical science, with droplet flow providing multiple advantages over standard single-phase microfluidics such as removal of Taylor dispersion, enhanced mixing, isolation of droplet contents from surfaces, and the ability to contain and address individual cells or biomolecules. Typically, a droplet microfluidic device is designed to produce droplets with well-defined sizes and compositions that flow through the device without interacting with channel walls. Successful droplet flow is fundamentally dependent on the microfluidic device - not only its geometry but moreover how the channel surfaces interact with the fluids.

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Exchanges of protein sequence modules support leaps in function unavailable through point mutations during evolution. Here we study the role of the two RAD51-interacting modules within the eight binding BRC repeats of BRCA2. We created 64 chimeric repeats by shuffling these modules and measured their binding to RAD51.

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The ability to effectively separate and isolate biological cells into specific and well-defined subpopulations is crucial for the advancement of our understanding of cellular heterogeneity and its relevance to living systems. Here is described the development of the functional phenotype flow cytometer (FPFC), a new device designed to separate cells on the basis of their in situ real-time phenotypic responses to stimuli. The FPFC performs a cascade of cell processing steps on a microfluidic platform: introduces biological cells one at a time into a solution of a biological reagent that acts as a stimulus, incubates the cells with the stimulus solution in a flow, and sorts the cells into subpopulations according to their phenotypic responses to the provided stimulus.

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Purpose: To report changes in the ocular surface and tear proteomics after discontinuation of chronic glaucoma medication.

Methods: Patients requiring trabeculectomy were recruited from the glaucoma clinic of Tampere University Hospital, Finland. Fifty-seven patients with previous history of anti-glaucomatous eye drops (8.

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The most common approach for the manufacture of oligonucleotides includes isolation of the active pharmaceutical ingredient (API) via lyophilization to provide a solid product, which is then dissolved to provide an aqueous formulation. It is well known from the development and manufacture of large molecules ("biologics") that API production does not always require isolation of solid API before drug product formulation, and this article provides technical considerations for the analogous use of oligonucleotide API in solution. The primary factor considered is solution stability, and additional factors such as viscosity, concentration, end-to-end manufacturing, microbiological control, packaging, and storage are also discussed.

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Uncovering the heterogeneity of cellular populations and multicellular constructs is a long-standing goal in fields ranging from antimicrobial resistance to cancer research. Emerging technology platforms such as droplet microfluidics hold the promise to decipher such heterogeneities at ultra-high-throughput. However, there is a lack of methods able to rapidly identify and isolate single cells or 3D cell cultures.

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Deep brain stimulation (DBS) has been proposed for severe, chronic, treatment-refractory obsessive-compulsive disorder (OCD) patients. Although serious adverse events can occur, only a few studies report on the safety profile of DBS for psychiatric disorders. In a prospective, open-label, interventional multi-center study, we examined the safety and efficacy of electrical stimulation in 30 patients with DBS electrodes bilaterally implanted in the anterior limb of the internal capsule.

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Functional annotation of novel proteins lags behind the number of sequences discovered by the next-generation sequencing. The throughput of conventional testing methods is far too low compared to sequencing; thus, experimental alternatives are needed. Microfluidics offer high throughput and reduced sample consumption as a tool to keep up with a sequence-based exploration of protein diversity.

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Developmental cell biology requires technologies in which the fate of single cells is followed over extended time periods, to monitor and understand the processes of self-renewal, differentiation, and reprogramming. A workflow is presented, in which single cells are encapsulated into droplets (Ø: 80 µm, volume: ≈270 pL) and the droplet compartment is later converted to a hydrogel bead. After on-chip de-emulsification by electrocoalescence, these 3D scaffolds are subsequently arrayed on a chip for long-term perfusion culture to facilitate continuous cell imaging over 68 h.

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The primary vaginal melanoma is a rare aggressive tumour with a poor prognosis. The average age at diagnosis is 60, and there are no known risk factors. The establishment of a classification system and treatment protocols are made difficult because there are so few cases.

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Background: The Medtronic Registry for Epilepsy (MORE; Medtronic Inc, Dublin, Ireland) is an open label observational study evaluating the long-term effectiveness, safety, and performance of deep brain stimulation (DBS) of the anterior nucleus of thalamus (ANT) for the treatment of refractory epilepsy.

Objective: To compare the difference in success rate of placing contacts at ANT-target region (ANT-TR) between transventricular (TV) and extraventricular (EV) lead trajectories in 73 ANT-DBS implants in 17 European centers participating in the MORE registry.

Methods: The success rate of placing contacts at ANT-TR was evaluated using a screening method combining both individual patient imaging information and stereotactic atlas information to identify contacts at ANT-TR.

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The success of ultrahigh-throughput screening experiments in directed evolution or functional metagenomics strongly depends on the availability of efficient technologies for the quantitative testing of a large number of variants. With advanced robotics, libraries of up to 10 clones can be screened per day as colonies on agar plates or cell lysates in microwell plates, albeit at high cost of capital, manpower and consumables. These cost considerations and the general need for high-throughput make miniaturization of assay volumes attractive.

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Screening of enzyme mutants in monodisperse picoliter compartments, generated at kilohertz speed in microfluidic devices, is coming of age. After a decade of proof-of-principle experiments, workflows have emerged that combine existing microfluidic modules to assay reaction progress quantitatively and yield improved enzymes. Recent examples of the screening of libraries of randomised proteins and from metagenomic sources suggest that this approach is not only faster and cheaper, but solves problems beyond the feasibility scope of current methodologies.

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Fluorescence anisotropy measurements of reagents compartmentalized into individual nanoliter droplets are shown to yield high-resolution binding curves from which precise dissociation constants (K) for protein-peptide interactions can be inferred. With the current platform, four titrations can be obtained per minute (based on ∼100 data points each), with stoichiometries spanning more than 2 orders of magnitude and requiring only tens of microliters of reagents. In addition to affinity measurements with purified components, K values for unpurified proteins in crude cell lysates can be obtained without prior knowledge of the concentration of the expressed protein, so that protein purification can be avoided.

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Ultrahigh-throughput screening, in which members of enzyme libraries compartmentalized in water-in-oil emulsion droplets are assayed, has emerged as a powerful format for directed evolution and functional metagenomics but is currently limited to fluorescence readouts. Here we describe a highly efficient microfluidic absorbance-activated droplet sorter (AADS) that extends the range of assays amenable to this approach. Using this module, microdroplets can be sorted based on absorbance readout at rates of up to 300 droplets per second (i.

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Abdominal wall endometriosis (AWE) is a rare type of endometriosis. Its pathophysiological pathways are still unknown. It generally occurs after surgical, mainly gynecological or obstetrical, interventions.

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