RNA and nucleotide recognition by synthetic receptors
In this project, we study extensively non-covalent interactions between nucleobases and artificial receptors to gain an understanding of the interaction strength, geometry of complexes, and selectivity of the generated colorimetric or fluorometric response. We recently developed a new bellows-type sensing mechanism for nucleotide detection in an aqueous solution. For instance, we have designed a pyrene-based cyclophane for ratiometric detection of ATP in an aqueous solution and applied it in creatine phosphatase assay. Another series of cyclophanes developed during the last year can bind to RNA sequences, specifically to those that contain C-rich subunits. We have shown that our naphthalimide-containing cyclophanes can encapsulate free cytosine and cytidine phosphates selectively in an aqueous solution with up to 60-fold fluorescence enhancement (JACS Au 2023, 3, 3, 964–977)
Control of self-assembly
One of the biggest challenges in supramolecular chemistry is the control of self-assembly in order to obtain desired structures with desired properties. Nature can easily perform this with the help of templates, it builds functional molecules in response to external stimuli or environmental factors. Our projects aim at mimicking this adaptive behavior of biological systems, namely transfer molecular information stored in the interacting species to the functions of self-assembled architectures (receptors, sensors or catalysts). An example below illustrate how hydrogen bonds and a chloride template control self-assembly process (Chem. – Eur. J. 2013, 19, 3710-3714)
Molecular switches and artificial signal transduction
Molecular switches are important topics for signal-processing at molecular level. We are looking at the molecular transformations in an unconventional way by combining molecular recognition events in one assembly to achieve such properties as reading, writing, memory, switching, logic operations and etc. We have developed a first cation molecular exchanger based on the cyclohexane ring. We have demostrated that binding of the zinc(II) cation to the bipyridine subunit induces the conformational switching of the crown ether subunits, which subsequently results in a release of the potassium cation. The release of the potassium cation can be detected by a cation sensor. (Org. Lett. 2018, 20 (19), 6211–6214)
Design of fluorescent sensors for analyte detection in water
It is still a challenge to rationally design cheap and selective sensors for certain analytes functioning in a competitive aqueous medium. Though the problem is partially solved using substrate-selective proteins which are modified with fluorescent labels, less expensive sensors with novel selectivities are required. In this project we develop a new approach for the design of fluorescence sensors for a series of substrates (phosphates, carboxylates, amino acids and amines) that are operating in aqueous solution. Our approach is based on the screening of dynamic combinatorial libraries consisting of metal cations and newly designed ligands bearing fluorophores, and a consecutive evaluation of the components that are responsible for a selective detection of a particular guest (Chem. Eur. J. 2018, 24(7), 1500-1504)