Publications by authors named "Jelle De Vos"

A proof-of-concept system is presented for the hyphenation of spatial comprehensive three-dimensional liquid chromatography (3D-LC) to mass spectrometry (MS) detection via a robotic-microfluidic interface. A three-dimensional fractal microflow distributor, incorporating 16 parallel RP monolithic capillary columns arranged in a 4 × 4 configuration, was connected to an X-Y-Z robotic system. This setup facilitated the deposition of successive arrays of microdroplets onto an MS target plate.

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Article Synopsis
  • Researchers aim to eliminate the binding of immunoglobulin Fc to Fc gamma receptors to prevent unwanted inflammation from therapeutic antibodies and fusion proteins.
  • A matched set of anti-CD20 antibodies with various Fc subclasses and variants were created to assess their binding activity to C1q and Fc-gamma receptors, as well as their performance in cell-based assays.
  • The findings showed that many variants retained significant activity in at least one assay but often had decreased temperature stability compared to the wild-type antibody.
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Monoclonal antibodies (mAbs) are large and highly heterogeneous species typically characterized using a plethora of analytical methodologies. There is a trend within the biopharmaceutical industry to combine several of these methods in one analytical platform to simultaneously assess multiple structural attributes. Here, a protein analyzer for the fully automated middle-up and bottom-up liquid chromatography-mass spectrometry (LC-MS) analysis of charge, size and hydrophobic variants is described.

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Article Synopsis
  • * The study investigates how layer thickness and exposure time affect channel dimensions and surface roughness, achieving an average surface roughness of less than 20% by optimizing these parameters.
  • * After thorough testing, the devices showed a maximum pressure resistance of 650 bar and successfully demonstrated a reversed-phase chromatographic separation of proteins using a specific mobile phase, highlighting their practical application potential.
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Spatial comprehensive three-dimensional chromatography (3D-LC) offers an innovative approach to achieve unprecedented resolving power in terms of peak capacity and sample throughput. This advanced technique separates components within a 3D separation space, where orthogonal retention mechanisms are incorporated. The parallel development of the second- and third-dimension stages effectively overcomes the inherent limitation of conventional multidimensional approaches, where sampled fractions are analyzed sequentially.

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The recent approval of messenger ribonucleic acid (mRNA) as vaccine to combat the COVID-19 pandemic has been a scientific turning point. Today, the applicability of mRNA is being demonstrated beyond infectious diseases, for example in cancer immunotherapy, protein replacement therapy and gene editing. mRNA is produced by in vitro transcription (IVT) from a linear DNA template and modified at the 3' and 5' ends to improve translational efficiency and stability.

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This study presents a comprehensive investigation of the mechanistic understanding of retention and selectivity in hydrophobic interaction chromatography. It provides valuable insights into crucial method-development parameters involved in achieving chromatographic resolution for profiling molecular variants of trastuzumab. Retention characteristics have been assessed for three column chemistries, i.

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Digital light processing (DLP) 3D printing is rapidly advancing and has emerged as a powerful additive manufacturing approach to fabricate analytical microdevices. DLP 3D-printing utilizes a digital micromirror device to direct the projected light and photopolymerize a liquid resin, in a layer-by-layer approach. Advances in vat and lift design, projector technology, and resin composition, allow accurate fabrication of microchannel structures as small as 18 × 20 µm.

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The present study discusses UHPLC method development allowing to establish ultra-high-resolution separations in gradient mode while operating at the kinetic performance limits, targeting the analysis of complex residual multi-class antibiotic samples in food products. The peak capacity and gradient occupation have been systematically assessed at different flow rates and gradient duration. The small particle size (1.

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The design aspects of microfluidic chips for spatial three-dimensional chromatography featuring an interconnected channel network and targeting protein analysis are discussed, and the corresponding kinetic performance limits have been established using a Pareto-optimality approach. The pros and cons to integrate different separation mechanisms (IEF, CE, SEC, RPLC, HILIC, HIC, and IEX) are discussed considering development stages in the spatial domain (LC) in the first and second dimension and time domain (LC) for the third dimension. Based on Pareto-optimization, we discuss the considerations of the channel length, particle diameter, and the effect of number of second- and third-dimension channels on the resulting peak capacity of a spatial IEF × SEC × RPLC device.

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The nucleocapsid protein (NP) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for several steps of the viral life cycle, and is abundantly expressed during infection, making it an ideal diagnostic target protein. This protein has a strong tendency for dimerization and interaction with nucleic acids. For the first time, high titers of NP were expressed in E.

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This study reports on the assessment of the separation performance of hydrophobic interaction chromatography for intact protein analysis using non-porous butyl polymethacrylate phases. The maximum peak capacity in inverse gradient mode was reached at a volumetric flow rate which was significantly (10-20 times) higher than the flow rate yielding the minimum plate height in isocratic mode, as the gradient volume dominates the peak-capacity generation. The flow rate yielding the maximum peak capacity increased with decreasing gradient volume, i.

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Background: Antibody tests are essential tools to investigate humoral immunity following SARS-CoV-2 infection or vaccination. While first-generation antibody tests have primarily provided qualitative results, accurate seroprevalence studies and tracking of antibody levels over time require highly specific, sensitive and quantitative test setups.

Methods: We have developed two quantitative, easy-to-implement SARS-CoV-2 antibody tests, based on the spike receptor binding domain and the nucleocapsid protein.

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The present contribution discusses recent advances in ultra-high-pressure liquid chromatography (UHPLC) and multi-dimensional liquid chromatography (MDLC) technology. First, new developments in UHPLC column technology and system design are highlighted. The latter includes a description of a novel injector concept enabling method speed-up, emerging detectors, and instrument diagnostics approaches.

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In spatial comprehensive three-dimensional chromatography (3D-LC) components are separated within a three-dimensional separation space that can lead to unprecedented resolving power, in terms of peak capacity and peak-production rate. The maximum peak capacity is the product of the peak capacities achieved in the individual dimensions when orthogonal retention mechanisms are incorporated. The parallel development of the second- and third-dimension separation stages overcomes the fundamental limitation of conventional multi-dimensional approaches, in which sampled fractions are analyzed sequentially.

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The performance of columns packed with 1.7 µm particles for aqueous size-exclusion chromatography was assessed at high-pressure conditions and linked to particle- and column-bed integrity. Decreasing the particle size from 3.

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A novel multilayer modulator chip offering a robust miniaturized interface for multidimensional liquid chromatography has been developed. The thermoplastic microfluidic device comprises five tailor-made functional layers, and the chip is compatible with commercially available switching-valve technology. The modulator chip allows for robust ultrahigh-pressure operation up to 65 MPa.

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We report on a numerical and experimental study of the limits of peak refocusing and concentration enhancement that can be obtained with solvent front-assisted peak remobilization in a trap column receiving peaks eluting from a preceding analytical column. It is shown that the upper limit of peak refocusing can best be pursued by injecting a sufficiently large volume in a sufficiently narrow capillary and elute it with a sufficiently steep (ballistic) gradient. Corresponding equations offering a quantitative description have been derived and verified experimentally.

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The ability to control the external porosity and to tune the dimensions of the macropore size on multiple length scales provides the possibility of tailoring the monolithic support structure towards separation performance. This paper discusses the properties of conventional polymer-monolithic stationary phases and its limitations regarding the effects of morphology on kinetic performance. Furthermore, guidelines to improve the macropore structure are discussed.

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This review describes chromatographic dispersion and different plate-height models frequently used to assess the chromatographic performance of ultra-high-pressure liquid chromatography column technology. Furthermore, different performance indices, including the resolution, the separation impedance, and kinetic plots are discussed allowing to quantify and visualize the resolving power in liquid chromatography. The construction of kinetic plots is explained, and different visualization approaches are highlighted.

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The current study comprises a systematic investigation to assess retention properties and selectivity of a mixed-mode reversed-phase/weak-anion-exchange (RP/WAX) stationary phase to aid method development. Retention was investigated for different compound classes which vary in hydrophobicity, van der Waals surface area, and charge as function of organic content, pH, and ionic strength of the mobile phase. The linear-solvent-strength model was successfully applied for aromatic hydrocarbons to obtain retention-time predictions based on log P values and van der Waals surface area values.

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We describe a liquid chromatography method development approach for the separation of intact proteins using hydrophobic interaction chromatography. First, protein retention was determined as function of the salt concentration by isocratic measurements and modeled using linear regression. The error between measured and predicted retention factors was studied while varying gradient time (between 15 and 120 min) and gradient starting conditions, and ranged between 2 and 15%.

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The characterization of biotherapeutics represents a major analytical challenge. This review discusses the current state-of-the-art in analytical technologies to profile biopharma products under native conditions, i.e.

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The present paper discusses practical aspects of prototyping of microfluidic chips using cyclic olefin copolymer as substrate and the application in high-performance liquid chromatography. The developed chips feature a 60mm long straight separation channel with circular cross section (500μm i.d.

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