A series of bisimidazolium salts were synthesized as novel guests for the macrocyclic host molecule cucurbituril (CB). These bisimidazolium-CB binary complexes exhibited a unique cage structure with the imidazolium rings acting as lids, leading to a size-dependent binding selectivity by altering the hydrophobic linker between the two imidazolium moieties. This new class of CB complexes was also capable of binding small solvent molecules, including acetone, acetonitrile, diethyl ether, and tetrahydrofuran (THF) in an aqueous environment.
Release of High-Energy Water as an Essential Driving Force for the High-Affinity Binding of Cucurbit[n]urilsFrank Biedermann, Vanya D. Uzunova, Oren A. Scherman, Werner M. Nau & Alfonso De Simone
Molecular dynamics simulations and isothermal titration calorimetry (ITC) experiments with neutral guests illustrate that the release of high-energy water from the cavity of cucurbit[n]uril (CBn) macrocycles is a major determinant for guest binding in aqueous solutions. The energy of the individual encapsulated water molecules decreases with increasing cavity size, because larger cavities allow for the formation of more stable H-bonded networks. Conversely, the total energy of internal water increases with the cavity size because the...
Associative chemosensing by fluorescent macrocycle–dye complexes – a versatile enzyme assay platform beyond indicator displacementFrank Biedermann, Denisa Hathazi & Werner M. Nau
Enzymatic reactions of aromatic substrates can be monitored by fluorescence with μM sensitivity in real time by using self-assembled fluorescent receptors.
Fluorescent Nanozeolite Receptors for the Highly Selective and Sensitive Detection of Neurotransmitters in Water and BiofluidsLaura Marie Grimm, Stephan Sinn, Marjan Krstić, Elisa D'Este, Ivo Sonntag, Eko Adi Prasetyanto, Thomas Kuner, Wolfgang Wenzel, Luisa De Cola & Frank Biedermann
Strongly Fluorescent, Switchable Perylene Bis(diimide) Host-Guest Complexes with Cucurbituril In WaterWerner M. Nau, Oren A. Scherman, Frank Biedermann, Einat Elmalem & Indrajit Ghosh
Supramolecular complexation of perylene bis(diimide) (PDI) dyes with the macrocyclic host cucurbituril (CB) prevents self-aggregation of the dye molecules and enables their use as highly (photo...
Triple Emission fromp-Dimethylaminobenzonitrile-Cucurbituril Triggers the Elusive Excimer EmissionMhejabeen Sayed, Frank Biedermann, Vanya D. Uzunova, Khaleel I. Assaf, Achikanath C. Bhasikuttan, Haridas Pal, Werner M. Nau & Jyotirmayee Mohanty
Abstract The intriguing dual-emission behavior of p- dimethylaminobenzonitrile (DMABN) and the identity of the associated excited states is, arguably, the most extensively investigated and also con...
High binding constants of 19 inorganic cations with the cucurbit[n]uril homologues (CBn, n = 5, 6, 7, 8) in water were determined and the far-reaching consequences and interferences of the high affinities (millimolar to micromolar) are discussed.
Benzobis(imidazolium)-Cucurbituril Complexes for Binding and Sensing Aromatic Compounds in Aqueous SolutionFrank Biedermann, Urs Rauwald, Monika Cziferszky, Kyle A. Williams, Lauren D. Gann, Bi Y. Guo, Adam R. Urbach, Christopher W. Bielawski & Oren A. Scherman
Abstract The utilities of benzobis(imidazolium) salts (BBIs) as stable and fluorescent components of supramolecular assemblies involving the macrocyclic host, cucurbituril (CB), are described...
Unimolecular chemosensor shows superior stability and detection capabilities in biofluids compared to bimolecular reporter pairs.
Rational design and implementation of a cucurbituril-based indicator-displacement assay for application in blood serumStephan Sinn, Eduard Spuling, Stefan Braese & Frank Biedermann
In this study, we report the first supramolecular indicator displacement assay (IDA) based on cucurbit[n]uril (CBn) host and a [2.2]paracyclophane derivative as indicator that is operational in blood serum.
The design of high-affinity and analyte-selective receptors operating in aqueous solutions is an outstanding problem in supramolecular chemistry. Directing the focus toward the unique properties of water, we present here a new strategy toward this goal and support it by molecular dynamics simulations and calorimetric measurements. We illustrate the procedure in the case of self-assembled 1:1 complexes of the rigid macrocycle cucurbituril (CB8) and dicationic auxiliary guests (AG). These CB8•AG complexes contain residual water molecules...
Signaling filopodia, termed cytonemes, are dynamic actin-based membrane structures that regulate the exchange of signaling molecules and their receptors within tissues. However, how cytoneme formation is regulated remains unclear. Here, we show that Wnt/PCP autocrine signaling controls the emergence of cytonemes, and that cytonemes subsequently control paracrine Wnt/β-catenin signal activation. Upon binding of the Wnt family member Wnt8a, the receptor tyrosine kinase Ror2 gets activated. Ror2/PCP signaling leads to induction of cytonemes, which mediate transport...
Cucurbituril Mediated Donor–Acceptor Ternary Complexes: A Model System for Studying Charge-Transfer InteractionsFrank Biedermann & Oren A. Scherman
A supramolecular self-assembly approach is described which allows for the convenient preparation of a wide range of charge-transfer (CT) donor–acceptor complexes in aqueous solutions. When one equiv of the macrocyclic host cucurbituril (CB) is added to an aqueous donor and acceptor solution, a heteroternary complex forms inside the host’s cavity with a well-defined face-to-face π–π-stacking geometry of the donor and acceptor. This heteroternary, CB-mediated complex offers the opportunity to study the CT phenomena at low...
Cucurbit[n]urils (CBn, n = 7, 8) serve as artificial receptors for steroids (21 tested), including the hormones testosterone and estradiol as well as steroidal drugs. Fluorescence displacement titrations and isothermal titration calorimetry (ITC) provided up to nanomolar binding affinities in aqueous solution for these hydrophobic target molecules, exceeding the values of known synthetic receptors. Remarkable binding selectivities, even for homologous steroid pairs, were investigated in detail by NMR, X-ray crystal diffraction, ITC, and quantum chemical...
Teaching old indicators even more tricks: binding affinity measurements with the guest-displacement assay (GDA)Stephan Sinn, Joana Krämer & Frank Biedermann
A simple change has important consequences: the guest-displacement assay (GDA) is introduced which allows for binding affinity determinations of supramolecular complexes with spectroscopically silent hosts and guests.
Noncovalent Chirality Sensing Ensembles for the Detection and Reaction Monitoring of Amino Acids, Peptides, Proteins, and Aromatic DrugsFrank Biedermann & Werner M. Nau
Strong and diagnostic induced circular dichroism signals in the near-UV or visible region are obtained when chiral, optically transparent analytes bind to an achiral chemosensing ensemble composed of...
Institute of Nanotechnology17
Karlsruhe Institute of Technology4
University of Cambridge3
Department of Chemistry and Earth Sciences2
Imperial College London2
Max Planck Institute for Medical Research1
International Baptist College and Seminary1
University of Strasbourg1