Self-Assembled Molecules – New Kind of Protein Ligands: Supramolecular Ligands

immunotargeting techniques; ligands; intramolecular immunological signals; congo red amyloid

The use of supramolecular structures as protein ligands

Congo red dye as well as other eagerly self-assembling organic molecules which form rod-like or ribbon-like supramolecular structures in water solutions, appears to represent a new class of protein ligands with possible wide-ranging medical applications. Such molecules associate with proteins as integral clusters and preferentially penetrate into areas of low molecular stability. Abnormal, partly unfolded proteins are the main binding target for such ligands, while well packed molecules are generally inaccessible. Of particular interest is the observation that local susceptibility for binding supramolecular ligands may be promoted in some proteins as a consequence of function-derived structural changes, and that such complexation may alter the activity profile of target proteins. Examples are presented in this paper

An outline of the use of supramolecular compounds in biology and medicine

Supramolecular chemistry opened up opportunities and prospects in biological studies. Numerous supramolecular systems are known which assume different shapes depending on the structure of the component molecules. Some of them are mixed systems. Ribbon-like supramolecular structures which are the main focus of this paper form complexes with proteins in a way which is a new type of interaction. Despite preserving the ribbonlike structure, it may also interact with proteins as a mixed system. In this way, it may be used as a carrier of drugs. In addition, hybrid systems created by a combination of ribbon-like supramolecular structures with carbon nanotubes were presented together with data from studies of these structures as drug-carrying systems. This paper presents an outline of the experimentally confirmed possible use of ribbon-like supramolecular systems

Plasmonic nanoparticles with supramolecular recognition

Even after more than two decades of intense studies, the research on self-assembly processes involving supramolecular interactions between nanoparticles (NPs) is continuously expanding. Plasmonic NPs have attracted particular attention due to strong optical, electrical, biological, and catalytic effects they are accompanied with. Surface plasmon resonance characteristics of plasmonic NPs and their assemblies enable fine-tuning of these effects with unprecedented dynamic range. In turn, the uniquely high polarizability of plasmonic nanostructures and related optical effects exemplified by surface-enhanced Raman scattering and red–blue color changes give rise to their application to biosensing. Since supramolecular interactions are ubiquitous in nature, scientists have found a spectrum of biomimetic properties of individual and assembled NPs that can be regulated by the layer of surface ligands coating all NPs. This paradigm has given rise to multiple studies from the design of molecular containers and enzyme-like catalysts to chiroplasmonic assemblies. Computational and theoretical advances in plasmonic effects for geometrically complex structures have made possible the nanoscale engineering of NPs, assemblies, and supramolecular complexes with biomolecules. It is anticipated that further studies in this area will be expanded toward chiral catalysis, environmental monitoring, disease diagnosis, and therapy

Stability of salts and complexes of humic acids

Základem práce je studium vlivu přítomnosti kovů inkorporovaných do struktury huminových látek při tepelné zátěži za přítomnosti vzdušného kyslíku. Pro tyto účely byla použita lignitická huminová kyselina, u které byl nejprve retitračně-vodivostní metodou stanoven počet vazných míst, tj. karboxylových skupin. Smícháním s roztoky sodných a měďnatých iontů byly získány koncové produkty s různými stupni nasycení zjištěných vazných míst. Pro zhodnocení termooxidační stability byla provedena termogravimetrická analýza a diferenční kompenzační kalorimetrie. Výsledky přinášejí nový pohled na reaktivitu huminové kyseliny s kovovými ionty v kapalné fázi, poukazují na možný vznik „porézní“ struktury sodných humátů a jejich schopnost retence vody.The ground of this work lies in the study of influence of metal ions incorporated onto the structure of humic substances during thermal stress in the presence of air oxygen. For these purposes, lignitic humic acid was used. The amount of binding sites, i.e. carboxylic groups, was determined by retitration-conductometric method. Mixing the humic acid with solutions of sodium and cupric ions gave the final products with different saturation degrees of detected binding sites. For the evaluation of thermooxidative stability, thermogravimetric analysis and differential scanning calorimetry were performed. The results bring new view upon the reactivity of humic acid with metal ions in the liquid state, indicate possible formation of “porous” structure of sodium humates and their water-retention ability.

Chemistry and light - part 2: light and energy

The conversion of solar energy into more useful forms of energy, such as chemical fuels or electricity, is one of the central problems facing modern science. Progress in photochemistry and chemical synthesis has led to a point where light energy conversion by means of artificial molecular devices can be rationally attempted. In this article, a general approach towards this challenging goal is presented

Smart systems related to polypeptide sequences

Increasing interest for the application of polypeptide-based smart systems in the biomedical field has developed due to the advantages given by the peptidic sequence. This is due to characteristics of these systems, which include: biocompatibility, potential control of degradation, capability to provide a rich repertoire of biologically specific interactions, feasibility to self-assemble, possibility to combine different functionalities, and capability to give an environmentally responsive behavior. Recently, applications concerning the development of these systems are receiving greater attention since a targeted and programmable release of drugs (e.g. anti-cancer agents) can be achieved. Block copolymers are discussed due to their capability to render differently assembled architectures. Hybrid systems based on silica nanoparticles are also discussed. In both cases, the selected systems must be able to undergo fast changes in properties like solubility, shape, and dissociation or swelling capabilities. This review is structured in different chapters which explain the most recent advances on smart systems depending on the stimuli to which they are sensitive. Amphiphilic block copolymers based on polyanionic or polycationic peptides are, for example, typically employed for obtaining pH-responsive systems. Elastin-like polypeptides are usually used as thermoresponsive polymers, but performance can be increased by using techniques which utilize layer-by-layer electrostatic self-assembly. This approach offers a great potential to create multilayered systems, including nanocapsules, with different functionality. Recent strategies developed to get redox-, magnetic-, ultrasound-, enzyme-, light-and electric-responsive systems are extensively discussed. Finally, some indications concerning the possibilities of multi-responsive systems are discussed.Postprint (published version