Publications by authors named "Jurriaan Huskens"

234 Publications

Selective uptake of thorium(IV) from nitric acid medium using two extraction chromatographic resins based on diglycolamide-calix[4]arenes: Application to thorium-uranyl separation in an actual sample.

J Chromatogr A 2021 Jul 9;1653:462401. Epub 2021 Jul 9.

Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede, the Netherlands. Electronic address:

Two novel extraction chromatography resins (ECRs) containing two diglycolamide (DGA) -functionalized calix[4]arenes with n-propyl and isopentyl substituents at the amide nitrogen atom, termed as ECR-1 and ECR-2, respectively, were evaluated for the uptake of Th(IV) from nitric acid feed solutions. While both the resins were having a quite high Th(IV) uptake ability (K >3000 at 3 M HNO), the uptake was relatively lower with the resin containing the isopentyl DGA, which appeared magnified at lower nitric acid concentrations. Kinetic modeling of the sorption data suggested fitting to the pseudo-second order model pointing to a chemical reaction during the uptake of the metal ion. Sorption isotherm studies were carried out showing a good fitting to the Langmuir and D-R isotherm models, suggesting the uptake conforming to monolayer sorption and a chemisorption model. Glass columns with a bed volume of ca. 2.5 mL containing ca. 0.5 g lots of the ECRs were used for studies to assess the possibility of actual applications of the ECRs. Breakthrough profiles obtained with feed containing 0.7 g/L Th(NO) solution resulted in breakthrough volumes of 8 and 5 mL, respectively, for the ECR-1 and ECR-2 resins. Near quantitative elution of the loaded metal ion was possible using a solution of oxalic acid and nitric acid. A method for the separation of Th-234 from natural uranium was demonstrated for the possible application of ECR-1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2021.462401DOI Listing
July 2021

Detection of Tumor DNA in Human Plasma with a Functional PLL-Based Surface Layer and Plasmonic Biosensing.

ACS Sens 2021 06 25;6(6):2307-2319. Epub 2021 May 25.

Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95122 Catania, Italy.

Standard protocols for the analysis of circulating tumor DNA (ctDNA) include the isolation of DNA from the patient's plasma and its amplification and analysis in buffered solutions. The application of such protocols is hampered by several factors, including the complexity and time-constrained preanalytical procedures, risks for sample contamination, extended analysis time, and assay costs. A recently introduced nanoparticle-enhanced surface plasmon resonance imaging-based assay has been shown to simplify procedures for the direct detection of tumor DNA in the patient's plasma, greatly simplifying the cumbersome preanalytical phase. To further simplify the protocol, a new dual-functional low-fouling poly-l-lysine (PLL)-based surface layer has been introduced that is described herein. The new PLL-based layer includes a densely immobilized CEEEEE oligopeptide to create a charge-balanced system preventing the nonspecific adsorption of plasma components on the sensor surface. The layer also comprises sparsely attached peptide nucleic acid probes complementary to the sequence of circulating DNA, e.g., the analyte that has to be captured in the plasma from cancer patients. We thoroughly investigated the contribution of each component of the dual-functional polymer to the antifouling properties of the surface layer. The low-fouling property of the new surface layer allowed us to detect wild-type and KRAS p.G12D-mutated DNA in human plasma at the attomolar level (∼2.5 aM) and KRAS p.G13D-mutated tumor DNA in liquid biopsy from a cancer patient with almost no preanalytical treatment of the patient's plasma, no need to isolate DNA from plasma, and without PCR amplification of the target sequence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acssensors.1c00360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8294610PMC
June 2021

Multivalent Affinity Profiling: Direct Visualization of the Superselective Binding of Influenza Viruses.

ACS Nano 2021 05 12;15(5):8525-8536. Epub 2021 May 12.

Department of Molecules & Materials, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands.

The influenza A virus (IAV) interacts with the glycocalyx of host cells through its surface proteins hemagglutinin (HA) and neuraminidase (NA). Quantitative biophysical measurements of these interactions may help to understand these interactions at the molecular level with the long-term aim to predict influenza infectivity and answer other biological questions. We developed a method, called multivalent affinity profiling (MAP), to measure virus binding profiles on receptor density gradients to determine the threshold receptor density, which is a quantitative measure of virus avidity toward a receptor. Here, we show that imaging of IAVs on receptor density gradients allows the direct visualization and efficient assessment of their superselective binding. We show how the multivalent binding of IAVs can be quantitatively assessed using MAP if the receptor density gradients are prepared around the threshold receptor density without crowding at the higher densities. The threshold receptor density increases strongly with increasing flow rate, showing that the superselective binding of IAV is influenced by shear force. This method of visualization and quantitative assessment of superselective binding allows not only comparative studies of IAV-receptor interactions, but also more fundamental studies of how superselectivity arises and is influenced by experimental conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.1c00166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8158855PMC
May 2021

Highly efficient uptake of neptunium from acidic feeds using two solid phase extraction resins containing diglycolamide-functionalized calix[4]arene ligands.

J Chromatogr A 2021 Apr 4;1642:462037. Epub 2021 Mar 4.

Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands. Electronic address:

Two solid phase extraction resins (SPER) were prepared by impregnating solutions of two diglycolamide-functionalized calix[4]arenes in 10% isodecanol in n-dodecane into Chromosorb W, as the stationary phase. While SPER-I contained n-propyl functionalized calix[4]arene, SPER-II contained the calix[4]arene with isopentyl groups at the carboxamide nitrogen atoms. The SPERs were characterized by SEM, TGA, FTIR, etc. and were used for the batch uptake of neptunium(IV) from nitric acid feed solutions. While the uptake of Np(IV) was extremely high with SPER-I (K: 47,544 at 3 M nitric acid, ca. 8% extractant loading), SPER-II displayed a significantly lower extraction efficiency (K: 13,724 under identical conditions) as indicated by the batch uptake studies. Sorption isotherm studies were carried out which indicated good fitting to the Langmuir model suggesting uptake conforming to monolayer sorption. Fitting to the D-R isotherm model conformed to a chemisorption model. Column studies were also carried out and the elution profiles, obtained with solutions of oxalic acid and nitric acid indicated very sharp peaks suggesting that the column can be used for the separation of Np(IV) from acidic radioactive feeds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2021.462037DOI Listing
April 2021

A Dynamic, Supramolecular View on the Multivalent Interaction between Influenza Virus and Host Cell.

Small 2021 04 7;17(13):e2007214. Epub 2021 Mar 7.

Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands.

Understanding how influenza viruses traverse the mucus and recognize host cells is critical for evaluating their zoonotic potential, and for prevention and treatment of the disease. The surface of the influenza A virus is covered with the receptor-binding protein hemagglutinin and the receptor-cleaving enzyme neuraminidase, which jointly control the interactions between the virus and the host cell. These proteins are organized in closely spaced trimers and tetramers to facilitate multivalent interactions with sialic acid-terminated glycans. This review shows that the individually weak multivalent interactions of influenza viruses allow superselective binding, virus-induced recruitment of receptors, and the formation of dynamic complexes that facilitate molecular walking. Techniques to measure the avidity and receptor specificity of influenza viruses are reviewed, and the pivotal role of multivalent interactions with their emergent properties in crossing the mucus and entering host cells is discussed. A model is proposed for the initiation of cell entry through virus-induced receptor clustering. The multivalent interactions of influenza viruses are maintained in a dynamic regime by a functional balance between binding and cleaving.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202007214DOI Listing
April 2021

Hierarchical Multivalent Effects Control Influenza Host Specificity.

ACS Cent Sci 2020 Dec 12;6(12):2311-2318. Epub 2020 Nov 12.

Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

Understanding how emerging influenza viruses recognize host cells is critical in evaluating their zoonotic potential, pathogenicity, and transmissibility between humans. The surface of the influenza virus is covered with hemagglutinin (HA) proteins that can form multiple interactions with sialic acid-terminated glycans on the host cell surface. This multivalent binding affects the selectivity of the virus in ways that cannot be predicted from the individual receptor-ligand interactions alone. Here, we show that the intrinsic structural and energetic differences between the interactions of avian- or human-type receptors with influenza HA translate from individual site affinity and orientation through receptor length and density on the surface into virus avidity and specificity. We introduce a method to measure virus avidity using receptor density gradients. We found that influenza viruses attached stably to a surface at receptor densities that correspond to a minimum number of approximately 8 HA-glycan interactions, but more interactions were required if the receptors were short and human-type. Thus, the avidity and specificity of influenza viruses for a host cell depend not on the sialic acid linkage alone but on a combination of linkage and the length and density of receptors on the cell surface. Our findings suggest that threshold receptor densities play a key role in virus tropism, which is a predicting factor for both their virulence and zoonotic potential.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acscentsci.0c01175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760459PMC
December 2020

Enhancement of Probe Density in DNA Sensing by Tuning the Exponential Growth Regime of Polyelectrolyte Multilayers.

Chem Mater 2020 Nov 26;32(21):9155-9166. Epub 2020 Oct 26.

Molecular NanoFabrication group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.

Surface-based biosensing devices benefit from a dedicated design of the probe layer present at the transducing interface. The layer architecture, its physicochemical properties, and the embedding of the receptor sites affect the probability of binding the analyte. Here, the enhancement of the probe density at the sensing interface by tuning the exponential growth regime of polyelectrolyte multilayers (PEMs) is presented. PEMs were made of poly-l-lysine (PLL), with appended clickable dibenzocyclooctyne (DBCO) groups and oligo(ethylene glycol) chains, and poly(styrene sulfonate) (PSS). The DNA probe loading and target hybridization efficiencies of the PEMs were evaluated as a function of the PLL layer number and the growth regime by a quartz crystal microbalance (QCM). An amplification factor of 25 in the target DNA detection was found for a 33-layer exponentially grown PEM compared to a monolayer. A Voigt-based model showed that DNA probe binding to the DBCO groups is more efficient in the open, exponentially grown films, while the hybridization efficiencies appeared to be high for all layer architectures. These results show the potential of such engineered gel-like structures to increase the detection of bio-relevant analytes in biosensing systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.chemmater.0c02454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7659331PMC
November 2020

Nanoscale Work Function Contrast Induced by Decanethiol Self-Assembled Monolayers on Au(111).

Langmuir 2020 Oct 19;36(42):12745-12754. Epub 2020 Oct 19.

Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.

In this paper, we obtain maps of the spatial tunnel barrier variations in self-assembled monolayers of organosulfurs on Au(111). Maps down to the sub-nanometer scale are obtained by combining topographic scanning tunneling microscopy images with d/d spectroscopy. The square root of the tunnel barrier height is directly proportional to the local work function and the d/d signal. We use ratios of the tunnel barriers to study the work function contrast in various decanethiol phases: the lying-down striped β phase, the dense standing-up φ phase, and the oxidized decanesulfonate λ phase. We compare the induced work function variations too: the work function contrast induced by a lying-down striped phase in comparison to the modulation induced by the standing-up φ phase, as well as the oxidized λ phase. By performing these comparisons, we can account for the similarities and differences in the effects of the mechanisms acting on the surface and extract valuable insights into molecular binding to the substrate. The pillow effect, governing the lowering of the work function due to lying-down molecular tails in the striped low density phases, seems to have quite a similar contribution as the surface dipole effect emerging in the dense standing-up decanethiol phases. The d/d spectroscopy map of the nonoxidized β phase compared to the map of the oxidized λ phase indicates that the strong binding of molecules to the substrate is no longer present in the latter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.0c02535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594278PMC
October 2020

Self-Induced Convection at Microelectrodes via Electroosmosis and Its Influence on Impact Electrochemistry.

J Am Chem Soc 2020 10 12;142(42):17908-17912. Epub 2020 Oct 12.

MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

Faradaic reactions at low supporting electrolyte concentrations induce convection via electroosmotic flows. Here we combine finite-element simulations and electrochemical measurements on microparticles at ultramicroelectrodes to explore this effect. We show that convection becomes the dominant form of mass transport for experiments at low salt concentrations, violating the common assumption that convection can be neglected.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.0c08450DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7582615PMC
October 2020

"Plug-n-Play" Polymer Substrates: Surface Patterning with Reactive-Group-Appended Poly-l-lysine for Biomolecule Adhesion.

ACS Appl Polym Mater 2019 Nov 1;1(11):3165-3173. Epub 2019 Oct 1.

Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

The immobilization of biomolecules onto polymeric surfaces employed in the fabrication of biomedical and biosensing devices is generally a challenging issue, as the absence of functional groups in such materials does not allow the use of common surface chemistries. Here we report the use of modified poly-l-lysine (PLL) as an effective method for the selective modification of polymeric materials with biomolecules. Cyclic olefin polymer (COP), Ormostamp, and polydimethylsiloxane (PDMS) surfaces were patterned with modified PLLs displaying either biotin or maleimide functional groups. Different patterning techniques were found to provide faithful microscale pattern formation, including micromolding in capillaries (MIMIC) and a hydrogel-based stamping device with micropores. The surface modification and pattern stability were tested with fluorescence microscopy, contact angle and X-ray photoelectron spectroscopy (XPS), showing an effective functionalization of substrates stable for over 20 days. By exploiting the strong biotin-streptavidin interaction or the thiol-maleimide coupling, DNA and PNA probes were displayed successfully on the surface of the materials, and these probes maintained the capability to specifically recognize complementary DNA sequences from solution. The printing of three different PNA-thiol probe molecules in a microarray fashion allowed selective DNA detection from a mixture of DNA analytes, demonstrating that the modified PLL methodology can potentially be used for multiplexed detection of DNA sequences.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsapm.9b00814DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7493307PMC
November 2019

Influenza-induced thrombocytopenia is dependent on the subtype and sialoglycan receptor and increases with virus pathogenicity.

Blood Adv 2020 07;4(13):2967-2978

Department of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands.

Thrombocytopenia is a common complication of influenza virus infection, and its severity predicts the clinical outcome of critically ill patients. The underlying cause(s) remain incompletely understood. In this study, in patients with an influenza A/H1N1 virus infection, viral load and platelet count correlated inversely during the acute infection phase. We confirmed this finding in a ferret model of influenza virus infection. In these animals, platelet count decreased with the degree of virus pathogenicity varying from 0% in animals infected with the influenza A/H3N2 virus, to 22% in those with the pandemic influenza A/H1N1 virus, up to 62% in animals with a highly pathogenic A/H5N1 virus infection. This thrombocytopenia is associated with virus-containing platelets that circulate in the blood. Uptake of influenza virus particles by platelets requires binding to sialoglycans and results in the removal of sialic acids by the virus neuraminidase, a trigger for hepatic clearance of platelets. We propose the clearance of influenza virus by platelets as a paradigm. These insights clarify the pathophysiology of influenza virus infection and show how severe respiratory infections, including COVID-19, may propagate thrombocytopenia and/or thromboembolic complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/bloodadvances.2020001640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7362372PMC
July 2020

Reactive Extraction Enhanced by Synergic Microwave Heating: Furfural Yield Boost in Biphasic Systems.

ChemSusChem 2020 Jul 25;13(14):3589-3593. Epub 2020 Jun 25.

Molecular NanoFabrication group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.

Reactive extraction is an emerging operation in the industry, particularly in biorefining. Here, reactive extraction was demonstrated, enhanced by microwave irradiation to selectively heat the reactive phase (for efficient reaction) without unduly heating the extractive phase (for efficient extraction). These conditions aimed at maximizing the asymmetries in dielectric constants and volumes of the reaction and extraction phases, which resulted in an asymmetric thermal response of the two phases. The efficiency improvement was demonstrated by dehydrating xylose (5 wt % in water) to furfural with an optimal yield of approximately 80 mol % compared with 60-65 mol % under conventional biphasic conditions, which corresponds to approximately 50 % reduction of byproducts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cssc.202000966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496589PMC
July 2020

Increasing the Sensitivity of Electrochemical DNA Detection by a Micropillar-Structured Biosensing Surface.

Langmuir 2020 04 14;36(16):4272-4279. Epub 2020 Apr 14.

Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

The available active surface area and the density of probes immobilized on this surface are responsible for achieving high specificity and sensitivity in electrochemical biosensors that detect biologically relevant molecules, including DNA. Here, we report the design of gold-coated, silicon micropillar-structured electrodes functionalized with modified poly-l-lysine (PLL) as an adhesion layer to concomitantly assess the increase in sensitivity with the increase of the electrochemical area and control over the probe density. By systematically reducing the center-to-center distance between the pillars (pitch), denser micropillar arrays were formed at the electrode, resulting in a larger sensing area. Azido-modified peptide nucleic acid (PNA) probes were click-reacted onto the electrode interface, exploiting PLL with appended oligo(ethylene glycol) (OEG) and dibenzocyclooctyne (DBCO) moieties (PLL-OEG-DBCO) for antifouling and probe binding properties, respectively. The selective electrochemical sandwich assay formation, composed of consecutive hybridization steps of the target complementary DNA (cDNA) and reporter DNA modified with the electroactive ferrocene functionality (rDNA-Fc), was monitored by quartz crystal microbalance. The DNA detection performance of micropillared electrodes with different pitches was evaluated by quantifying the cyclic voltammetric response of the surface-confined rDNA-Fc. By decrease of the pitch of the pillar array, the area of the electrode was enhanced by up to a factor 10.6. A comparison of the electrochemical data with the geometrical area of the pillared electrodes confirmed the validity of the increased sensitivity of the DNA detection by the design of the micropillar array.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.0c00144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7191753PMC
April 2020

Influenza as a molecular walker.

Chem Sci 2020 Jan 14;11(1):27-36. Epub 2019 Nov 14.

Molecular Nanofabrication Group , MESA + Institute for Nanotechnology , Faculty of Science and Technology , University of Twente , P.O. Box 217 , 7500 AE Enschede , The Netherlands . Email:

The surface of the influenza virus is decorated with the receptor-binding protein hemagglutinin (HA) and the receptor-cleaving enzyme neuraminidase (NA). HA is responsible for host cell recognition, while NA prevents aggregation and entrapment, but the intricate mechanism of how the functions of these glycoproteins cooperate and how they are regulated by mutational responses to environmental pressures remains unclear. Recently, several groups have described the motion of influenza over surfaces and reported that this motion is inhibited by NA inhibitors. We argue that the motion of influenza resembles the motility of artificial receptor-cleaving particles called "molecular spiders". The cleaving of receptors by this type of molecular walkers leads to self-avoiding motion across a surface. When the binding and cleaving rates of molecular spiders are balanced, they move both rapidly and efficiently. The studies of molecular spiders offer new insights into the functional balance of HA and NA, but they do not address the asymmetric distribution of HA and NA on the surface of influenza. We propose that receptor-cleaving molecular walkers could play an important role in the further investigation of the motility of influenza viruses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9sc05149jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7021193PMC
January 2020

Recruitment of receptors at supported lipid bilayers promoted by the multivalent binding of ligand-modified unilamellar vesicles.

Chem Sci 2020 Mar 9;11(12):3307-3315. Epub 2020 Mar 9.

Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente P.O. Box 217 Enschede 7500 AE The Netherlands

The development of model systems that mimic biological interactions and allow the control of both receptor and ligand densities, is essential for a better understanding of biomolecular processes, such as the recruitment of receptors at interfaces, at the molecular level. Here we report a model system based on supported lipid bilayers (SLBs) for the investigation of the clustering of receptors at their interface. Biotinylated SLBs, used as cell membrane mimics, were functionalized with streptavidin (SAv), used here as receptor. Subsequently, biotinylated small (SUVs) and giant (GUVs) unilamellar vesicles were bound to the SAv-functionalized SLBs by multivalent interactions and found to induce the recruitment of both SAv on the SLB surface and the biotin moieties in the vesicles. The recruitment of receptors was investigated with quartz crystal microbalance with dissipation monitoring (QCM-D), which allowed the identification of the biotin and SAv densities necessary to obtain receptor recruitment. At approx. 0.6% of biotin in the vesicles, a transition between dense and low vesicle packing was observed, which coincided with the transitions between recruitment in the vesicles recruitment in the SLB and between full and partial use of the biotin moieties in the vesicle. Direct optical visualization of the clustering at the interface of individual GUVs with the SLB platform was achieved with fluorescence microscopy, showing recruitment of SAv at the contact area as well as the deformation of the vesicles upon binding. Different vesicle binding regimes were observed for lower and higher biotin densities in the vesicles and at the SLBs. A more quantitative analysis of the molecular parameters implied in the interaction, indicated that approx. 10% of the vesicle area constitutes the contact area. Moreover, the SUV binding and recruitment appeared to be fast on the analysis time scale, whereas the binding of GUVs is slower due to the larger SLB area over which SAv recruitment needs to occur. The mechanisms revealed in this study may provide insight in biological processes in which recruitment occurs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc00518eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152591PMC
March 2020

Correction: Influenza as a molecular walker.

Chem Sci 2020 Feb 18;11(9):2567. Epub 2020 Feb 18.

Molecular Nanofabrication Group, MESA + Institute for Nanotechnology, Faculty of Science and Technology, University of Twente P.O. Box 217 7500 AE Enschede The Netherlands

[This corrects the article DOI: 10.1039/C9SC05149J.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sc90015jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8157483PMC
February 2020

Multivalency in Heteroternary Complexes on Cucurbit[8]uril-Functionalized Surfaces: Self-assembly, Patterning, and Exchange Processes.

Chempluschem 2019 09 12;84(9):1324-1330. Epub 2019 Jun 12.

Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, Department of Science and Technology, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands.

The spatial confinement of multivalent azopyridine guest molecules mediated by cucurbit[8]urils is described. Fluorescent dye-labelled multivalent azopyridine molecules were attached to preformed methyl viologen/cucurbit[8]uril inclusion complexes in solution and at surfaces. The formation of the resulting heteroternary host-guest complexes was verified in solution and on gold substrates. Surface binding constants of the multivalent ligands were two orders of magnitude higher than that of the monovalent one. Poly-l-lysine grafted with oligo(ethylene glycol) and maleimide moieties was deposited on cyclic olefin polymer surfaces and further modified with thiolated methyl viologen and cucurbit[8]uril. Defined micrometer-sized patterns were created by soft lithographic techniques. Supramolecular exchange experiments were performed on these surface-bound heterocomplexes, which allowed the creation of cross-patterns by taking advantage of the molecular valency, which led to the substitution of the monovalent guest by the multivalent guests but not vice versa.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cplu.201900181DOI Listing
September 2019

Surface Modification with Control over Ligand Density for the Study of Multivalent Biological Systems.

ChemistryOpen 2020 01 8;9(1):53-66. Epub 2020 Jan 8.

Molecular NanoFabrication group MESA+ Institute for Nanotechnology University of Twente Enschede The Netherlands.

In the study of multivalent interactions at interfaces, as occur for example at cell membranes, the density of the ligands or receptors displayed at the interface plays a pivotal role, affecting both the overall binding affinities and the valencies involved in the interactions. In order to control the ligand density at the interface, several approaches have been developed, and they concern the functionalization of a wide range of materials. Here, different methods employed in the modification of surfaces with controlled densities of ligands are being reviewed. Examples of such methods encompass the formation of self-assembled monolayers (SAMs), supported lipid bilayers (SLBs) and polymeric layers on surfaces. Particular emphasis is given to the methods employed in the study of different types of multivalent biological interactions occurring at the functionalized surfaces and their working principles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/open.201900290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6948118PMC
January 2020

Stochastic electrochemistry at ultralow concentrations: the case for digital sensors.

Analyst 2020 Feb;145(3):750-758

MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

There is increasing demand, in particular from the medical field, for assays capable of detecting sub-pM macromolecular concentrations with high specificity. Methods for detecting single bio/macromolecules have already been developed based on a variety of transduction mechanisms, which represents the ultimate limit of mass sensitivity. Due to limitations imposed by mass transport and binding kinetics, however, achieving high concentration sensitivity additionally requires the massive parallelization of these single-molecule methods. This leads to a new sort of 'digital' assay based on large numbers of parallel, time-resolved measurements aimed at detecting, identifying and counting discrete macromolecular events instead of reading out an average response. In this Tutorial Review we first discuss the challenges inherent to trace-level detection and the motivations for developing digital assays. We then focus on the potential of recently developed single-entity impact electrochemistry methods for use in digital sensors. These have the inherent advantage of relying on purely electrical signals. They can thus in principle be implemented using integrated circuits to provide the parallelization, readout and analysis capabilities required for digital sensors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9an01832hDOI Listing
February 2020

Elucidating the Thermodynamic Driving Forces of Polyanion-Templated Virus-like Particle Assembly.

J Phys Chem B 2019 11 12;123(46):9733-9741. Epub 2019 Nov 12.

A virus in its most simple form is comprised of a protein capsid that surrounds and protects the viral genome. The self-assembly of such structures, however, is a highly complex, multiprotein, multiinteraction process and has been a topic of study for a number of years. This self-assembly process is driven by the (mainly electrostatic) interaction between the capsid proteins (CPs) and the genome as well as by the protein-protein interactions, which primarily rely on hydrophobic interactions. Insight in the thermodynamics that is involved in virus and virus-like particle (VLP) formation is crucial in the detailed understanding of this complex assembly process. Therefore, we studied the assembly of CPs of the cowpea chlorotic mottle virus (CCMV) templated by polyanionic species (cargo), that is, single-stranded DNA (ssDNA), and polystyrene sulfonate (PSS) using isothermal titration calorimetry. By separating the electrostatic CP-cargo interaction from the full assembly interaction, we conclude that CP-CP interactions cause an enthalpy change of -3 to -4 kcal mol CP. Furthermore, we quantify that upon reducing the CP-CP interaction, in the case of CCMV by increasing the pH to 7, the CP-cargo starts to dominate VLP formation. This is highlighted by the three times higher affinity between CP and PSS compared to CP and ssDNA, resulting in the disassembly of CCMV at neutral pH in the presence of PSS to yield PSS-filled VLPs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpcb.9b06258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875872PMC
November 2019

Tandem Si Micropillar Array Photocathodes with Conformal Copper Oxide and a Protection Layer by Pulsed Laser Deposition.

ACS Appl Mater Interfaces 2019 Nov 25;11(44):41402-41414. Epub 2019 Oct 25.

This work demonstrates the influence of high-quality protection layers on Si-CuO micropillar arrays created by pulsed laser deposition (PLD), with the goal to overcome photodegradation and achieve long-term operation during photoelectrochemical (PEC) water splitting. Sequentially, we assessed planar and micropillar device designs with various design parameters and their influence on PEC hydrogen evolution reaction. On the planar device substrates, a CuO film thickness of 600 nm and a CuO/CuO heterojunction layer with a 5:1 thickness ratio between CuO to CuO were found to be optimal. The planar Si/CuO/CuO heterostructure showed a higher PV performance ( = 20 mA/cm) as compared to the planar Si/CuO device, but micropillar devices did not show this improvement. Multifunctional overlayers of ZnO (25 nm) and TiO (100 nm) were employed by PLD on Si/CuO planar and micropillar arrays to provide a hole-selective passivation layer that acts against photocorrosion. A micropillar Si/ITO-Au/CuO/ZnO/TiO/Pt stack was compared to a planar device. Under optimized conditions, the Si/CuO photocathode with Pt as a HER catalyst displayed a photocurrent of 7.5 mA cm at 0 V vs RHE and an onset potential of 0.85 V vs RHE, with a stable operation for 75 h.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b14408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838789PMC
November 2019

Remarkable Enhancement in Extraction of Trivalent -Block Elements Using a Macrocyclic Ligand with Four Diglycolamide Arms: Synthesis, Extraction, and Spectroscopic and Density Functional Theory Studies.

Inorg Chem 2019 Nov 14;58(21):14885-14899. Epub 2019 Oct 14.

Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology , University of Twente , P.O. Box 217, 7500 AE Enschede , The Netherlands.

A multiple diglycolamide (DGA)-containing ligand having four DGA arms tethered to a tetraaza-12-crown-4 ring, viz. 2,2',2'',2'''-(((1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(2-oxoethane-2,1-diyl)) tetrakis (oxy)) tetrakis(-dioctylacetamide) (T12C4ODGA), was synthesized and evaluated for the extraction of different actinide and lanthanide ions, viz. Am, Eu, Pu, Np, and UO. The extraction efficiency of the present ligand was found to be the highest reported so far, more specifically for the trivalent metal ions Am and Eu, when one considers the very low ligand concentration used in the present study, compared to that of the various previously reported multiple DGA-based ligands. The nature of the complexes formed during the extraction of Eu was investigated using time-resolved fluorescence (TRFS) and extended X-ray absorption fine structure (EXAFS) spectroscopy. Both the solvent extraction and TRFS studies indicated the presence of 1:1 and 1:2 complexes during the extraction of Am and Eu having three inner-sphere water molecules in the 1:1 complex. Density functional theoretical (DFT) studies were performed on the Am and Eu complexes of both T12C4ODGA and an analogous compound having methyl groups in place of the -octyl groups, and the DFT results of the T12C4ODGA nicely explain the extraction behavior of Am and Eu.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.inorgchem.9b02605DOI Listing
November 2019

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies.

Inorg Chem 2019 Jul 10;58(13):8633-8644. Epub 2019 Jun 10.

Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology , University of Twente , P.O. Box 217, 7500 AE Enschede , The Netherlands.

A series of four N-pivot tripodal diglycolamide (DGA) ligands, where three DGA moieties are attached to the central N atom via spacers of different lengths and with varying alkyl substituents on the amidic nitrogen of DGA (L-L), were studied for their extraction and complexation ability toward trivalent lanthanide/actinide ions, including solvent extraction, complexation using spectrophotometric titrations, and luminescence spectroscopic studies. Introduction of a methyl group on the amidic nitrogen atom gives rise to a 400 fold increase of the Eu distribution ( D) value [L (NMe) vs L (NH)] at 1 M HNO. Enlargement of the spacer length between the pivotal N atom and the DGA moieties with one carbon atom results in a 14 times higher D value [L (C3) vs L (C2)]. Slope analyses showed that Eu was extracted as a bis-solvated species with all four ligands. The compositions of the Eu/L complexes were further confirmed by spectroscopic measurements, its formation constants following the order: L > L > L > L. Luminescence spectroscopy and electrospray ionization mass spectrometry revealed that all four ligands form [Eu(L)(NO)] complexes. Density functional theory and thermodynamic parameters corroborated the existence of [Eu(L)(NO)] complexes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.inorgchem.9b00985DOI Listing
July 2019

Hypersound-Enhanced Intracellular Delivery of Drug-Loaded Mesoporous Silica Nanoparticles in a Non-Endosomal Pathway.

ACS Appl Mater Interfaces 2019 Jun 23;11(22):19734-19742. Epub 2019 May 23.

State Key Laboratory of Precision Measuring Technology & Instruments , Tianjin University , Tianjin 300072 , China.

The intracellular delivery efficiency of drug-loaded nanocarriers is often limited by biological barriers arising from the plasma membrane and the cell interior. In this work, the entering of doxorubicin (Dox)-loaded mesoporous silica nanoparticles (MSNs) into the cytoplasm was acoustically enhanced through direct penetration with the assistance of hypersound of gigahertz (GHz) frequency. Both fluorescence and cell viability measurements revealed that the therapeutic efficacy of Dox-loaded MSNs was significantly improved by tuning the power and duration of hypersound on demand with a nanoelectromechanical resonator. Mechanism studies with inhibitors illustrated that the membrane defects induced by the hypersound-triggered GHz acoustic streaming facilitated the Dox-loaded MSNs of 100-200 nm to directly penetrate through the cell membrane instead of via the traditional endocytosis, which highly increased the delivery efficiency by avoiding the formation of endosomes. This acoustic method enables the drug carriers to overcome biological barriers of the cell membrane and the endosomes without the limitation of carrier materials, which provides a versatile way of enhanced drug delivery for biomedical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b02447DOI Listing
June 2019

Maskless Spatioselective Functionalization of Silicon Nanowires.

ChemNanoMat 2018 Aug 29;4(8):874-881. Epub 2018 May 29.

Molecular NanoFabrication MESA+ Institute for Nanotechnology University of Twente P.O. Box 217 7500 AE Enschede The Netherlands.

Spatioselective functionalization of silicon nanowires was achieved without using a masking material. The designed process combines metal-assisted chemical etching (MACE) to fabricate silicon nanowires and hydrosilylation to form molecular monolayers. After MACE, a monolayer was formed on the exposed nanowire surfaces. A second MACE step was expected to elongate the nanowires, thus creating two different segments. When monolayers of 1-undecene or 1-tetradecyne were formed on the upper segment, however, the second MACE step did not extend the nanowires. In contrast, nanowires functionalized with 1,8-nonadiyne were elongated, but at an approximately 8 times slower etching rate. The elongation resulted in a contrast difference in high-resolution scanning electron microscopy (HR-SEM) images, which indicated the formation of nanowires that were covered with a monolayer only at the top parts. Click chemistry was successfully used for secondary functionalization of the monolayer with azide-functionalized nanoparticles. The spatioselective presence of 1,8-nonadiyne gave a threefold higher particle density on the upper segment functionalized with 1,8-nonadiyne than on the lower segment without monolayer. These results indicate the successful spatioselective functionalization of silicon nanowires fabricated by MACE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cnma.201800072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473541PMC
August 2018

Integration of Molybdenum-Doped, Hydrogen-Annealed BiVO with Silicon Microwires for Photoelectrochemical Applications.

ACS Sustain Chem Eng 2019 Mar 7;7(5):5034-5044. Epub 2019 Feb 7.

PhotoCatalytic Synthesis and Molecular NanoFabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

H-BiVO :Mo was successfully deposited on microwire-structured silicon substrates, using indium tin oxide (ITO) as an interlayer and BiOI prepared by electrodeposition as precursor. Electrodeposition of BiOI, induced by the electrochemical reduction of -benzoquinone, appeared to proceed through three stages, being nucleation of particles at the base and bottom of the microwire arrays, followed by rapid (homogeneous) growth, and termination by increasing interfacial resistances. Variations in charge density and morphology as a function of spacing of the microwires are explained by (a) variations in mass transfer limitations, most likely associated with the electrochemical reduction of -benzoquinone, and (b) inhomogeneity in ITO deposition. Unexpectedly, H-BiVO :Mo on microwire substrates (4 μm radius, 4 to 20 μm spacing, and 5 to 16 μm length) underperformed compared to H-BiVO :Mo on flat surfaces in photocatalytic tests employing sulfite (SO ) oxidation in a KPi buffer solution at pH 7.0. While we cannot exclude optical effects, or differences in material properties on the nanoscale, we predominantly attribute this to detrimental diffusion limitations of the redox species within the internal volume of the microwire arrays, in agreement with existing literature and the observations regarding the electrodeposition of BiOI. Our results may assist in developing high-efficiency PEC devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acssuschemeng.8b05756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410602PMC
March 2019

Weak Multivalent Binding of Influenza Hemagglutinin Nanoparticles at a Sialoglycan-Functionalized Supported Lipid Bilayer.

ACS Nano 2019 03 12;13(3):3413-3423. Epub 2019 Mar 12.

Molecular Nanofabrication Group, MESA + Institute for Nanotechnology, Faculty of Science and Technology , University of Twente , P.O. Box 217, 7500 AE Enschede , The Netherlands.

Quantification of the multivalent interactions of influenza viruses binding at interfaces may provide ways to tackle key biological questions regarding influenza virulence and zoonoses. Yet, the deconvolution of the contributions of molecular and interfacial parameters, such as valency, interaction area, and receptor density, to the binding of whole viruses is hindered by difficulties in the direct determination of these parameters. We report here a chemical platform technology to study the binding of multivalent recombinant hemagglutinin (rHA) nanoparticles at artificial sialoglycan cell receptor-presenting interfaces in which all these parameters can be derived, thus allowing the desired full and quantitative binding analysis. SiO substrates were functionalized with supported lipid bilayers containing a targeted and tunable fraction of a biotinylated lipid, followed by the adsorption of streptavidin and biotinylated polyvalent 2,3- or 2,6-sialyl lactosamine (SLN). rHA nanoparticles were used as a virus mimic to provide a good prediction of the number of interactions involved in binding. Low nanomolar affinities and selectivities for binding at the 2,6-SLN platforms were observed for rHA particles from three different virus variants. When fitting the data to a multivalency model, the nanomolar overall affinity appears to be achieved by 6-9 HA-sugar molecular interaction pairs, which individually present a rapid association/dissociation behavior. This dynamic behavior may be an essential biological attribute in the functioning of the influenza virus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.8b09410DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6439437PMC
March 2019

Unprecedented Inversion of Selectivity and Extraordinary Difference in the Complexation of Trivalent f Elements by Diastereomers of a Methylated Diglycolamide.

Chemistry 2019 Apr 20;25(21):5507-5513. Epub 2019 Mar 20.

Laboratory of Molecular Nanofabrication, Mesa+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE, Enschede, The Netherlands.

When considering f elements, solvent extraction is primarily used for the removal of lanthanides from ore and their recycling, as well as for the separation of actinides from used nuclear fuel. Understanding the complexation mechanism of metal ions with organic extractants, particularly the influence of their molecular structure on complex formation is of fundamental importance. Herein, we report an extraordinary (up to two orders of magnitude) change in the extraction efficiency of f elements with two diastereomers of dimethyl tetraoctyl diglycolamide (Me -TODGA), which only differ in the orientation of a single methyl group. Solvent extraction techniques, extended X-ray absorption fine structure (EXAFS) measurements, and density functional theory (DFT) based ab initio calculations were used to understand their complex structures and to explain their complexation mechanism. We show that the huge differences observed in extraction selectivity results from a small change in the complexation of nitrate counter-ions caused by the different orientation of one methyl group in the backbone of the extractant. The obtained results give a significant new insight into metal-ligand complexation mechanisms, which will promote the development of more efficient separation techniques.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.201806161DOI Listing
April 2019

Low-fouling, mixed-charge poly-l-lysine polymers with anionic oligopeptide side-chains.

J Mater Chem B 2018 Dec 5;6(46):7662-7673. Epub 2018 Nov 5.

Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici, c/o Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Catania, Italy.

Biosensors and biomedical devices require antifouling surfaces to prevent the non-specific adhesion of proteins or cells, for example, when aiming to detect circulating cancer biomarkers in complex natural media (e.g., in blood plasma or serum). A mixed-charge polymer was prepared by the coupling of a cationic polyelectrolyte and an anionic oligopeptide through a modified "grafting-to" method. The poly-l-lysine (PLL) backbone was modified with different percentages (y%) of maleimide-NHS ester chains (PLL-mal(y%), from 13% to 26%), to produce cationic polymers with specific grafting densities, obtaining a mixed-charge polymer. The anionic oligopeptide structure (CEEEEE) included one cysteine (C) and five glutamic acid (E) units, which were attached to the PLL-mal(y%) polymers, preadsorbed on gold substrates, through the thiol-maleimide Michael-type addition. Contact angle and PM-IRRAS data confirmed monolayer formation of the modified PLLs. Antifouling properties of peptide-PLL surfaces were assessed in adsorption studies using quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance imaging (SPRI) techniques. PLL-mal(26%)-CEEEEE showed the best antifouling performance in single-protein solutions, and the nonspecific adsorption of proteins was 46 ng cm using diluted human plasma samples. The new PLL-mal(26%)-CEEEEE polymer offers a prominent low-fouling activity in complex media, with rapid and simple procedures for the synthesis and functionalization of the surface compared to conventional non-fouling materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8tb01619dDOI Listing
December 2018

Controlled and Tunable Loading and Release of Vesicles by Using Gigahertz Acoustics.

Angew Chem Int Ed Engl 2019 01 30;58(1):159-163. Epub 2018 Nov 30.

Molecular Nanofabrication group, MESA+ Institute for Nanotechnology, University of Twente, 7500 AE, Enschede, The Netherlands.

Controllable exchange of molecules between the interior and the external environment of vesicles is critical in drug delivery and micro/nano-reactors. While many approaches exist to trigger release from vesicles, controlled loading remains a challenge. Herein, we show that gigahertz acoustic streaming generated by a nanoelectromechanical resonator can control the loading and release of cargo into and from vesicles. Polymer-shelled vesicles showed loading and release of molecules both in solution and on a solid substrate. We observed deformation of individual giant unilamellar vesicles and propose that the shear stress generated by gigahertz acoustic streaming induces the formation of transient nanopores, with diameters on the order of 100 nm, in the vesicle membranes. This provides a non-invasive method to control material exchange across membranes of different types of vesicles, which could allow site-specific release of therapeutics and controlled loading into cells, as well as tunable microreactors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201810181DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391938PMC
January 2019
-->