Transient signal generation in a self-assembled nanosystem fueled by ATP

A fundamental difference exists in the way signal generation is dealt with in natural and synthetic systems. While nature uses the transient activation of signalling pathways to regulate all cellular functions, chemists rely on sensory devices that convert the presence of an analyte into a steady output signal. The development of chemical systems that bear a closer analogy to living ones (that is, require energy for functioning, are transient in nature and operate out-of-equilibrium) requires a paradigm shift in the design of such systems. Here we report a straightforward strategy that enables transient signal generation in a self-assembled system and show that it can be used to mimic key features of natural signalling pathways, which are control over the output signal intensity and decay rate, the concentration-dependent activation of different signalling pathways and the transient downregulation of catalytic activity. Overall, the reported methodology provides temporal control over supramolecular processe

Photoswitchable catalysis by a nanozyme mediated by a lightsensitive cofactor

The activity of a gold nanoparticle-based catalyst can be reversibly up- and down-regulated by light. Light is used to switch a small molecule between cis- and trans-isomers, which inhibits the catalytic activity of the nanoparticles to different extent. The system is functional in aqueous buffer, which paves the way for integrating the system in biological networks

Transient self-assembly of molecular nanostructures driven by chemical fuels

Over the past decades, chemists have mastered the art of assembling small molecules into complex nanostructures using non-covalent interactions. The driving force for self-assembly is thermodynamics: the self-assembled structure is more stable than the separate components. However, biological self-assembly processes are often energetically uphill and require the consumption of chemical energy. This allows nature to control the activation and duration of chemical functions associated to the assembled state. Synthetic chemical systems that operate in the same way are essential for creating the next generation of intelligent, adaptive materials, nanomachines and delivery systems. This review focuses on synthetic molecular nanostructures which assemble under dissipative conditions. The chemical function associated to the transient assemblies is operational as long as chemical fuel is present

Combinatorial chemistry: covalent versus dynamic approach

A review on the concept of dynamic combinatorial chem. (DCC) and illustration in which areas of DCC has been applied and to which extend success has been achieved. In. Topics covered include chem. bond formation under thermodn. control, applications of DCC, DCC for detecting weak interactions, and systems chem

Dynamic Covalent Capture: A sensitive tool for detecting molecular interactions

Molecular recognition is at the centre of many areas of chemistry. Examples are analytical chemistry (analyte-sensor), catalysis (transition state-catalyst), medicinal chemistry (drug-biotarget) and advanced materials chemistry (building block A-building block B). Methodology that allows the rapid and precise detection of molecular recognition events is essential in all these fields. Traditionally, molecular recognition has been studied based on a rational design approach involving many iterative optimisation loops, which makes it an energy- and time consuming process. Additionally, it requires detailed knowledge about the target and the recognition process itself, information which is not always available. Currently, combinatorial methods are increasingly being used for detecting molecular recognition events, allowing the simultaneous screening of a vast amount of chemical compounds enabling a much larger part of chemical space to be explored. Dynamic covalent capture extends on the combinatorial approach for detecting molecular recognition events, but at a higher sensitivity level compared to conventional methodologies and with the novelty of self-selection by the target. The essential point of dynamic covalent capture is that a molecular recognition event is followed by the formation of a reversible covalent bond between the two molecule

Converting-enzyme inhibition experiences with captopril in hypertensive patients

In westerse landen is verhoogde bloeddruk een veel voorkomende ziekte en een belangrijke factor in de sterfte ten gevolge van hart- en vaatziekten. Wanneer hypertensie behandeld wordt, blijken mortaliteit en morbiditeit af te nemen. Adequate behandeling is daarom wenselijk, maar de behandeling zal meestal aspecifiek zijn aangezien bij het merendeel van de patiënten geen oorzakelijke factor kan worden aangetoond. Inzicht in (patho)fysiologische processen van belang bij de regulatie van de bloeddruk zal kunnen leiden tot een meer doelgerichte therapie. ... Zie: Samenvatting