Wilhelm Huck

Wilhelm Huck
Radboud University | RU · Institute for Molecules and Materials

Prof. Dr.

About

286
Publications
51,895
Reads
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28,465
Citations
Additional affiliations
January 2010 - present
Radboud University
Position
  • Professor of physical organic chemistry
October 1999 - December 2012
University of Cambridge
Position
  • Lecturer-Reader-Professor
August 1997 - September 1999
Harvard University
Position
  • PostDoc Position

Publications

Publications (286)
Article
Delineating design principles of biological systems by reconstitution of purified components offers a platform to gauge the influence of critical physicochemical parameters on minimal biological systems of reduced complexity. Here we unravel the effect of strong reversible inhibitors on the spatiotemporal propagation of enzymatic reactions in a con...
Article
Full-text available
The field of stem cells and regenerative medicine offers considerable promise as a means of delivering new treatments for a wide range of diseases. In order to maximize the effectiveness of cell-based therapies - whether stimulating expansion of endogenous cells or transplanting cells into patients - it is essential to understand the environmental...
Article
Full-text available
Liquid-liquid phase transitions in complex mixtures of proteins and other molecules produce crowded compartments supporting in vitro transcription and translation. We developed a method based on picoliter water-in-oil droplets to induce coacervation in Escherichia coli cell lysate and follow gene expression under crowded and noncrowded conditions....
Article
Cell-free protein expression, or in vitro transcription and translation, has the potential to test and predict the behavior of synthetic bio-circuits, as it allows detailed studies on mechanisms and kinetics of transcription and translation. A major hurdle however is the fact that in bacterial gene expression systems in vitro, transcription and tra...
Article
The number of circulating tumor cells (CTCs) in blood is strongly correlated with the progress of metastatic cancer. Current methods to detect CTCs are based on immunostaining or discrimination of physical properties. Herein, a label-free method is presented exploiting the abnormal metabolic behavior of cancer cells. A single-cell analysis techniqu...
Article
The number of circulating tumor cells (CTCs) in blood is strongly correlated with the progress of metastatic cancer. Current methods to detect CTCs are based on immunostaining or discrimination of physical properties. Herein, a label-free method is presented exploiting the abnormal metabolic behavior of cancer cells. A single-cell analysis techniqu...
Article
Liposomes are self-assembled phospholipid vesicles with great potential in fields ranging from targeted drug delivery to artificial cells. The formation of liposomes using microfluidic techniques has seen considerable progress, but the liposomes formation process itself has not been studied in great detail. As a result, high throughput, high-yieldi...
Article
In recent years, technologies capable of analyzing single cells have emerged that are transforming many fields of biological research. Herein we report how DNA-functionalized hydrogel beads can serve as a matrix to capture mRNA from lysed single cells. mRNA quantification free of pre-amplification bias is ensured by using padlock probes and rolling...
Article
Herein, we describe a simple and robust approach to repeatedly modify surfaces with polymer brushes through surface-initiated atomic transfer radical polymerization (SI-ATRP), based on an initiator-embedded polystyrene sheet that does not rely on specific surface chemistries for initiator immobilization. The surface-grafted polymer brushes can be w...
Article
The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavio...
Article
Polymer brushes are attractive polymeric coatings for biomedical applications such as tissue engineering, biosensor design and the purification of biological samples. In order to confer bioactivity to these coatings, their functionalisation with biomolecules, proteins and peptides, is required. In this respect, thiol–ene coupling offers interesting...
Article
In droplet-based microfluidics, non-ionic, high-molecular weight surfactants are required to stabilize droplet interfaces. One of the most common structures that imparts stability as well as biocompatibility to water-in-oil droplets is a triblock copolymer surfactant composed of perfluoropolyether (PFPE) and polyethylene glycol (PEG) blocks. Howeve...
Article
In highly crowded and viscous intracellular environments, the kinetics of complex enzymatic reactions are determined by both reaction and diffusion rates. However in vitro studies on transcription and translation often fail to take into account the density of the prokaryotic cytoplasm. Here we mimic the cellular environment, using a porous hydrogel...
Article
Full-text available
Understanding the dynamics of complex enzymatic reactions in highly crowded small volumes is crucial for the development of synthetic minimal cells. Compartmentalized biochemical reactions in cell-sized containers exhibit a degree of randomness due to the small number of molecules involved. However, it is unknown how the physical environment contri...
Article
Full-text available
Water-in-oil-in-water (w/o/w) microfluidics double emulsions offer a new route to compartmentalise reagents into isolated aqueous microenvironments while maintaining an aqueous carrier fluid phase; this enables compatibility with commercial flow cytometry systems such as fluorescence-activated cell sorting (FACS). Double emulsion (inner core) defor...
Article
The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule solutions, like the cytosol, are very prone to non-...
Article
Our knowledge of the properties and dynamics of complex molecular reaction networks, for example those found in living systems, considerably lags behind the understanding of elementary chemical reactions. In part, this is because chemical reactions networks are non-linear systems that operate under conditions far from equilibrium. Of particular int...
Article
Full-text available
Living cells are able to produce a wide variety of biological responses when subjected to biochemical stimuli. It has become apparent that these biological responses are regulated by complex chemical reaction networks (CRNs). Unravelling the function of these circuits is a key topic of both systems biology and synthetic biology. Recent progress at...
Article
The flow environment in inner cores of water-in-oil-in-water (w/o/w) microfluidic double emulsions has a significant impact on industrial applications of such systems. For example, in the case of shear sensitive cells compartmentalised in the cores, high shear conditions may be deleterious. This study reports on the flow characteristics of w/o/w in...
Article
Full-text available
Life is sustained by complex systems operating far from equilibrium and consisting of a multitude of enzymatic reaction networks. The operating principles of biology's regulatory networks are known, but the in vitro assembly of out-of-equilibrium enzymatic reaction networks has proved challenging, limiting the development of synthetic systems showi...
Article
Full-text available
The cytosol of an E. coli cell is extremely crowded, containing 20-30 % (v/v) macromolecules. Such conditions are expected to increase activity coefficients and result in excluded volume effects, driving complexation, multimerization and compact conformations of macromolecules. Experimentally, crowding is often simulated by high concentrations of i...
Article
Full-text available
Droplet microfluidics is combined with bio-orthogonal thiol–ene click chemistry to fabricate micrometer-sized, monodisperse fibrinogen-containing hyaluronic acid hydrogel microbeads in a mild, radical-free procedure in the presence of human mesenchymal stem cells (hMSCs). The gel beads serve as microniches for the 3D culture of single hMSCs, contai...
Patent
We describe a method of layer-by-layer deposition of a plurality of layers of material onto the wall or walls of a channel of a microfluidic device, the method comprising: loading a tube with a series of segments of solution, a said segment of solution bearing a material to be deposited; coupling said tube to said microfluidic device; and injecting...
Article
Full-text available
Red blood cells (RBCs) undergo extensive deformation when travelling through the microcapillaries. Deformability, the combined result of properties of the membrane-cytoskeleton complex, the surface area-to-volume ratio, and the hemoglobin content, is a critical determinant of capillary blood flow. During blood bank storage and in many pathophysiolo...
Data
Supplemental Video 1: Deformation and relaxation of RBCs passing through microfluidic channels mimicking microcirculation in vivo. RBCs transit through the microchannels with an axisymmetric bullet-like shape. They relax back to their initial disc-like shape as soon as they exit into the relaxation zone.
Patent
This invention relates to microfluidic systems and more particularly to methods and apparatus for accessing the contents of micro droplets (114) in an emulsion stream. A method of accessing the contents of a droplet (114) of an emulsion in a microfluidic system, the method comprising: flowing the emulsion alongside a continuous, non-emulsive stream...
Article
A wet stamping method to precisely control concentrations of enzymes and inhibitors in place and time inside layered gels is reported. By combining enzymatic reactions such as autocatalysis and inhibition with spatial delivery of components through soft lithographic techniques, a biochemical reaction network capable of recognizing the spatial distr...
Article
The flow topology in moving microdroplets has a significant impact on the behaviour of encapsulated objects and hence on applications of the technology. This study reports on a systematic investigation of the flow field inside droplets moving in a rectangular microchannel, by means of micro-particle image velocimetry (µPIV). Various water/oil (w/o)...
Article
We report that the transit-time of photogenerated holes within an OPV device is significantly controlled by the interface between the photoactive layer and the electrode. We used time-resolved optical absorption spectroscopy to track the evolution and transport of photogenerated holes in situ within efficient PTB7:PC70BM (thieno [3,4-b] thiophene/b...
Article
Mechanically strong supramolecular hydrogels (up to 98.9% water content) were obtained by the combination of a rigid, fully π-conjugated polymer backbone and zwitterionic side chains. The gels were characterized by SAXS, SEM and rheology measurements and are fluorescent, stimuli responsive (temperature, salts) and bind DNA.
Article
Droplet-based microfluidics is increasingly used for biological applications, where the recovery of cells or particles after an experiment or assay is desirable. Here, we present an electro-demulsification chip which circumvents the use of harsh chemicals and multiple washing/centrifugation steps and offers a mild way for extracting cells and polym...
Patent
A light-emissive device comprising a light-emissive material provided between first and second electrodes such that charge carriers can move between the first and second electrodes and the light-emissive material, wherein the device includes a layer of a polymer blend provided between the first and second electrodes, phase separation of the polymer...
Article
A wet stamping method to precisely control concentrations of enzymes and inhibitors in place and time inside layered gels is reported. By combining enzymatic reactions such as autocatalysis and inhibition with spatial delivery of components through soft lithographic techniques, a biochemical reaction network capable of recognizing the spatial distr...
Article
Full-text available
We microfluidically fabricate bio-orthogonal DNA-functionalized porous hydrogels from hyaluronic acid that are employed in in vitro transcription/translation (IVTT) of a green fluorescent protein. By co-encapsulating individual hydrogel particles and the IVTT machinery in water-in-oil microdroplets, we study protein expression in a defined reaction...
Article
Full-text available
Here, we report a convenient experimental platform to study the diffusion of Ca(2+) in the presence of a Ca(2+)-binding protein (Calbindin D28k). This work opens up new possibilities to elucidate the physical chemistry of complex Ca(2+)-dependent reaction-diffusion networks that are abundant in living cells.
Article
Surface adhesion is regulated by sparsely grafting responsive hydrophilic polymer chains on superhydrophobic surfaces but without obviously changing the wettability. We study experimentally how adhesion of superhydrophobic surfaces affects liquid slip. The slip length of water on such surfaces decays quickly as the adhesive force increases. This in...
Article
Cell culturing, whether for tissue engineering or cell biology studies, always involves placing cells in a non-natural environment and no material currently exist that can mimic the entire complexity of natural tissues and variety of cell-matrix interactions that is found in vivo. Here, we review the vast range of hydrogels, composed of natural or...
Article
Full-text available
Many approaches to mimic and understand the dynamics of vesicle budding lack precise control over vesicle membrane properties or require external stimuli to induce budding. We use copolymer-loaded double-emulsion droplets to precisely control size, size distribution, composition and morphology of giant polymersomes. By tuning the copolymer concentr...
Article
"…︁ Our mastery of working across the boundaries of disciplines should encompass more than being a supplier of fine molecules to biologists, materials scientists and physicists. We have a tremendous opportunity to broaden our discipline and study the very core fundamentals of biology …︁" Read more in the Editorial by W. T. S. Huck.
Article
Full-text available
Here we report the application of monodisperse double emulsion droplets, produced in a single step within partially hydrophilic/partially hydrophobic microfluidic devices, as defined containers for quantitative flow cytometric analysis. Samples with varying fluorophore concentrations were generated, and a clear correlation between dye concentration...
Article
We report a microfluidic approach to generate aqueous droplets in oil of different dimensionality, stabilized by a lipid monolayer, to systematically probe the polymerization of bacterial cell-division protein FtsZ into fibrous networks as a function of the concentrations of crowding agent, FtsZ, and GTP. FtsZ bundles confined in droplets were dyna...
Article
Full-text available
A series of water-soluble macro-initiators is synthesized to avoid radical loss in microfluidic on-chip photo cross-linking of hyaluronic acid methacrylate-containing water-in-oil emulsions. Their superior performance over known photo-initiators through the generation of water-soluble radicals and excellent biocompatibility are demonstrated.
Article
Full-text available
Interfaces between a poly(3-hexylthiophene) [P3HT] and an end-grafted (brush) layer of poly(methyl methacrylate) [PMMA] are shown using neutron reflectometry to be dependent on heat treatment. Annealing the samples allows part of the brush layer to cross into the P3HT layer creating a very asymmetric interface. We suggest that the P3HT rearrangemen...
Article
Full-text available
Here, we present a platform to detect cytokine (IL-2, IFN-γ, TNF-α) secretion of single, activated T-cells in droplets over time. We use a novel droplet-based microfluidic approach to encapsulate cells in monodisperse agarose droplets together with functionalized cytokine-capture beads for subsequent binding and detection of secreted cytokines from...
Article
Full-text available
A droplet-based microfluidics technique is used to produce monodisperse, 80 μm collagen–gelatin beads with tunable mechanical properties in the range of 1–10 kPa after photo-crosslinking. The gel beads are porous, mechanically robust and stable in buffer, but can be degraded enzymatically. Encapsulated fibroblast cells maintain 70% viability after...
Article
Brushing up on polymers: A difference in electrochemical potential allows surface-initiated atom-transfer radical polymerization on a sandwiched metal substrate using microliter volumes. Cu(I) activators are continuously generated and diffuse to the initiator-modified substrate, while Cu(II) deactivators maintain polymerization. Polymer-brush gradi...
Article
Eine elektrochemische Potentialdifferenz kann genutzt werden, um in eingeschlossenen Mikrolitervolumina zwischen zwei Metallsubstraten eine radikalische Atomtransferpolymerisation auszulösen. In ihrer Zuschrift auf S. 9295 ff. erzeugen W. T. S. Huck, W. Liu, F. Zhou et al. durch Anwendung einzelner 10‐μL‐Lösungströpfchen Polymerbürsten in kontrolli...
Article
Electrochemical potential difference can be used to activate atom‐transfer radical polymerization catalysts in a sandwiched metal substrate with microliter volumes. In their Communication on page 9125 ff., W. T. S. Huck, W. Liu, F. Zhou et al. use a single droplet solution (10 μL) to grow polymer brushes in controlled gradients and other complex sh...
Article
We report a microfluidic droplet-based approach enabling the measurement of chemical reactions of individual enzyme molecules and its application to a single-molecule-counting immunoassay. A microfluidic device is used to generate and manipulate < 10-fL droplets at rates of up to 1.3 × 10(6) per second, about two orders of magnitude faster than has...
Article
A study of the organic semiconductor F8TBT is presented, directly comparing a conventional form (F8TBT-out) with a form with varied alkyl side-chain position (F8TBT-in), in terms of optical properties and device performance in light-emitting-diodes (LEDs). Computational simulations of the side-chain position with respect to the TBT unit reveal geom...
Article
Full-text available
In this paper, we investigated the intra-species bacterial quorum sensing at the single cell level using a double droplet trapping system. Escherichia coli transformed to express the quorum sensing receptor protein, LasR, were encapsulated in microdroplets that were positioned adjacent to microdroplets containing the autoinducer, N-(3-oxododecanoyl...
Article
We report that we can enhance the performance of polymer photovoltaics by introducing materials with dipoles at the donor–acceptor interface of the polymer solar cells. We use a zwitterionic conjugated polyelectrolyte (ZCPE) as an interfacial layer in a model bi-layer system consisting of donor and acceptor polymers. We find an increase in short-ci...
Article
Nonspecific protein adsorption is a central challenge for the use of polymeric materials in biological media. While the quantity of adsorbed protein can be lowered, very few surfaces are protein resistant when exposed to undiluted serum or plasma. The underlying principles of this fouling and the adsorbing proteins remain to be identified. Here, we...
Article
The intricacy of the different parameters involved in cell adhesion to biomaterials and fate decision (e.g. proliferation, differentiation, apoptosis) makes the decoupling of the respective effects of surface properties, extra-cellular matrix protein adsorption and ultimately cell behaviour difficult. This work presents a micro-patterned polymer br...
Article
Droplet-based fluidics is emerging as a powerful platform for single cell analysis, directed evolution of enzymes, and high throughput screening studies. Due to the small amounts of compound compartmentalised in each droplet, detection has been primarily by fluorescence. To extend the range of experiments that can be carried out in droplets we have...
Article
We report the electronic properties of the conjugated coupling between a donor polymer and an acceptor segment serving as a model for the coupling in conjugated donor-acceptor block copolymers. These structures allow the study of possible intra-chain photoinduced charge separation, in contrast to the inter-chain separation achieved in conventional...
Article
We present results on laser action from liquid crystal compounds whereby one sub-unit of the molecular structure consists of the cyano-substituted chromophore, {phenylene-bis (2-cyanopropene)}, similar to the basic unit of the semiconducting polymer structure poly(cyanoterephthalylidene). These compounds were found to exhibit nematic liquid crystal...
Article
There has been phenomenal effort synthesizing new low-band gap polymer hole-conductors which absorb into the near-infrared (NIR), leading to >10% efficient all-organic solar cells. However, organic light absorbers have relatively narrow bandwidths, making it challenging to obtain panchromatic absorption in a single organic semiconductor. Here, we d...
Article
Surface initiated atom transfer radical polymerization (ATRP) was triggered after diffusion of a CuI/L activator generated at a working electrode. A stable [CuIIL]/[CuIL] ratio gradient was formed at the gap between the working electrode and initiator terminated substrate due to ion diffusion. The size of the gap can be used to dictate polymer grow...
Article
We have demonstrated capture and release of underwater-oil droplets based on fouling-resistant surfaces coated with pH-responsive polymer brushes. In response to the change of environmental pH, oil droplets were captured on the polymer brush-modified surfaces in the high adhesion state. As the droplet volume increased upon coalescence with other oi...
Article
We present a fast and efficient in situ synthetic approach to obtain fully π-conjugated polymers with degrees of polymerization up to 23 and near quantitative (>95%) heterobis-functionalization. The synthesis relies on the key advantages of controlled Suzuki chain-growth polymerization: control over molecular weight, narrow polydispersity, and abil...
Article
Microgel particles are formed from aqueous-two-phase-system (ATPS) droplets in poly(dimethylsiloxane) (PDMS) microfluidic devices. The droplets consist of a dextran core and a photopolymerizable poly(ethylene glycol) diacrylate (PEGDA) shell. Upon UV exposure, the ATPS droplets undergo a shape-transformation yielding PEGDA microgel particles contai...
Article
Converting the DEAD: A fluidic approach to generate precisely defined water-oil interfaces was used to quantify the influence of the water surface (blue drops) on chemical reactions between quadricyclane or β-pinene and diethyl azodicarboxylate (DEAD). This method allows for easy investigation of the "on water" effect.