In vivo accumulation of self-assembling dye Congo red in an area marked by specific immune complexes: possible relevance to chemotherapy.

Supramolecular micellar structures have been proposed as carriers in aim-oriented drug transportation to a target marked by specific immune complexes. In this study, the self-assembling dye Congo red was used as a model supramolecular carrier and its accumulation in the target was studied in vivo. The target was created in vivo as the local specific inflammation provoked by subcutaneous injection of antigen to the ear of a previously immunized rabbit. The color caused by accumulation of Congo red after its intravenous injection was registered by pictures of the ear with suitably filtered visible light shining through it to distinguish Congo red against the background color of hemoglobin. The results confirmed the expected accumulation and retention of Congo red in the inflammation area marked by deposits of specific immune complexes. The role of albumin and its possible interference with transportation of drugs through the blood by supramolecular carriers was also subjected to preliminary examination. The results revealed that albumin collaborates rather than interferes with drug transportation; this is another factor making the use of supramolecular carriers for aim-oriented chemotherapy highly promising

In vivo accumulation of self-assembling dye Congo red in an area marked by specific immune complexes : possible relevance to chemotherapy

Supramolecular micellar structures have been proposed as carriers in aim-oriented drug transportation to a target marked by specific immune complexes. In this study, the self-assembling dye Congo red was used as a model supramolecular carrier and its accumulation in the target was studied in vivo. The target was created in vivo as the local specific inflammation provoked by subcutaneous injection of antigen to the ear of a previously immunized rabbit. The color caused by accumulation of Congo red after its intravenous injection was registered by pictures of the ear with suitably filtered visible light shining through it to distinguish Congo red against the background color of hemoglobin. The results confirmed the expected accumulation and retention of Congo red in the inflammation area marked by deposits of specific immune complexes. The role of albumin and its possible interference with transportation of drugs through the blood by supramolecular carriers was also subjected to preliminary examination. The results revealed that albumin collaborates rather than interferes with drug transportation; this is another factor making the use of supramolecular carriers for aim-oriented chemotherapy highly promising

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

Silver ions as EM marker of congo red ligation sites in amyloids and amyloid-like aggregates

Congo red (CR) which is known to act as selective amyloid ligand may when binds to these protein forms reflect their internal molecular structure. The disclosure by EM of sites binding the dye and their distribution in amyloids and amyloid-like aggregates formed in vitro is the focus of our work. In order to produce the required contrast, CR has been indirectly combined with metal via including by intercalation of Titan yellow (TY) which exhibits relatively strong affinity for silver ions. The resulting combined ligand retains its ability to bind to proteins which it owes to CR and can easily be detected in EM studies thanks to TY less active in penetration to proteins. We have found however that in protein aggregates where unfolding is stabilized by aggregation and therefore irreversible, TY alone may serve as both ligand and metal carrier.The formation of ordered structures in amyloids were studied using IgG light chains with amyloidogenic properties, converted into amyloids through shaking. The resulting EM images were subjected to interpretation on the basis of the authors’ earlier research into the CR/light chain complexation process. Results indicate that dimeric light chains, which are the subject of our study, produce amyloids or amyloid-like complexes with chain-like properties and strong helicalization tendencies. Cursory analysis suggests that edge polypeptide loops belonging to unstable light chains form intermolecular bridges which promote creation of loose gel deposits, or are otherwise engaged in swapping processes leading to higher structural ordering.</jats:p

Dispersion of single-wall carbon nanotubes with supramolecular Congo red : properties of the complexes and mechanism of the interaction

A method of dispersion of single-wall carbon nanotubes (SWNTs) in aqueous media using Congo red (CR) is proposed. Nanotubes covered with CR constitute the high capacity system that provides the possibility of binding and targeted delivery of different drugs, which can intercalate into the supramolecular, ribbon-like CR structure. The study revealed the presence of strong interactions between CR and the surface of SWNTs. The aim of the study was to explain the mechanism of this interaction. The interaction of CR and carbon nanotubes was studied using spectral analysis of the SWNT–CR complex, dynamic light scattering (DLS), differential scanning calorimetry (DSC) and microscopic methods: atomic force microscopy (AFM), transmission (TEM), scanning (SEM) and optical microscopy. The results indicate that the binding of supramolecular CR structures to the surface of the nanotubes is based on the "face to face stacking". CR molecules attached directly to the surface of the nanotubes can bind further, parallel-oriented molecules and form supramolecular and protruding structures. This explains the high CR binding capacity of carbon nanotubes. The presented system – containing SWNTs covered with CR – offers a wide range of biomedical applications

Influence of fertilisation type and harvest date on lignin content and structural carbohydrates in meadow plants

The nutritional value of green forage is a result of various pratotechnical practices, including fertilisation and harvest timing. Additionally, individual plant species present in natural grasslands may respond differently to those practices. The study aimed to investigate the effect of fertilisation type (farm yard manure (FYM) and NPK fertilisation) and the timing of the first regrowth harvest of meadow sward (ten harvest dates) on the lignin and structural carbohydrates of three dicotyledonous meadow plants: Taraxacum officinale F.H. Wigg., Achillea millefolium L. and Lotus corniculatus L. Plant material was harvested from 28 Apr until 26 Jun at 7-day intervals and analysed for cellulose (CL), hemicellulose (HCL), and acid detergent lignin (ADL). The levels of neutral detergent fibre (NDF), acid detergent fibre (ADF), and ADL were measured using near-infrared spectroscopy (NIRS) with a NIRFlex N-500 device. Cellulose was calculated as the difference between ADF and ADL, while HCL was calculated by subtracting ADF from NDF. T. officinale had the lowest HCL (average 65.5 g∙kg−1 DM) and ADL content (47.1 g∙kg−1 DM) while A. millefolium had the highest CL content (266.5 g∙kg−1 DM) and ADL (52.3 g∙kg−1 DM). In contrast, L. corniculatus accumulated the highest HCL (104.5 g∙kg−1 DM) and the lowest CL content (246.1 g∙kg−1 DM). An increase in all studied parameters content was observed with later harvest dates. On average, plants fertilised with FYM contained lower amounts of structural carbohydrates and ADL compared to those fertilised with NPK