Partitioning of model toxins to hydrophobically terminated DAB dendrimers

Abstract

Dendrimers are attractive in biological and biomedical applications due to the similarity in their molecular size to biologically relevant molecules and the large number of chain ends available functionalization. In the current work, we examined the potential of diamino butane (DAB) dendrimers functionalized with long alkyl chains as partitioning agents for hydrophobic toxins for use as a prefiltering stage in a bioartiticial liver. DAB dendrimers of various generations that had been previously fully modified with palmitoyl chloride were obtained. A study of the kinetics of partitioning of acetylsalicylic acid (ASA) suggested that while significant toxin removal occurred in 30 s, although a slight time dependent increase in removal was noted up to 60 minutes. The partitioning of 6 hydrophobic toxins from aqueous solution to the modified dendrimers in 30 minutes was examined. The results demonstrated that a number of factors, including the pKa of the toxin, its octanol water partitioning coefficient and molecular size contributed to the level of toxin removal. Toxin removal on a molar basis increased with increasing dendrimer generation for all toxins, with the modified G5 dendrimers partitioning 50 -100 toxin molecules in most cases. Dendrimer modification with C4 alkyl chains rather than Cl5 chains significantly decreased toxin removal, although chains longer than C10 seemed to partition equal amounts of toxins. The results of the study demonstrate that water-soluble dendrimers modified with hydrophobic end groups may be useful for the removal of toxins from the blood in a prereaction step for a bioartificial liver, but that a better understanding of the molecular mechanisms of removal may be necessary before it is possible to predict the levels of toxin removal. B 2004 Wiley Periodicals, Inc.

Radiation-induced grafting of carbon nanotubes on HPLC silica microspheres: theoretical and practical aspects

“…Aromatic acids (salicylic, acetylsalicylic, benzoic, phenylacetic) and amines (pyridine, benzidine, aniline) were as well injected on this column and eluted with ACN-water (10 : 90), 1 mL min À1 , at two different pHs, 2.3 and 7, based on the chemicals' dissociation constants of the analytes. 23,24 As expected, elution was signicantly affected by pH. Organic acids were more retained and better separated at acidic pH, most likely due to the highest interaction with MWCNTs and lower hydrophilicity of the undissociated species.…”

Pharmacological Evaluation of Novel Organoiron Dendrimers as Antimicrobial and Anti‐Inflammatory Agents

“…the availability of internal cavities, make dendrimers unique in many applications such as drug delivery, solar cells, catalysis, and electrochemical sensors. [4][5][6][7][8][9] Over the past decade, significant applications of dendrimers for biological and drug-delivery purposes have been demonstrated. [10][11][12][13][14][15][16][17] There is a direct correlation between dendrimer generation and the functional groups in their periphery, which improves the presentation of concentrated drugs or designated molecules for therapeutic applications.…”

Electrochemistry of Non-Redox-Active Poly(propylenimine) and Poly(amidoamine) Dendrimers at Liquid−Liquid Interfaces

“…The highly structured characteristics make dendrimers very suitable molecules for a wide range of biomedical applications, ,,,,, including in in vitro diagnostics, in drug delivery, ,,,,− as unimolecular micelles, , and as the mimics of proteins. , However, the biological properties of dendrimers need to be more deeply investigated to enable further therapeutic applications . Dendrimers are also used as catalysts, ,,,− combining the advantages of homogeneous and heterogeneous catalysts. , Metallodendrimers with interesting electronic, magnetic, and catalytic properties have been reported. , The structure, size, shape, and solubility of dendrimers and metallodendrimers can be tuned, and the catalytic sites of a metallodendrimer can be located either at the periphery of the dendrimer or at the core. ,, Other applications of dendrimers are their use as encapsulating agents for insoluble materials (e.g., metals), , self-assembled monolayers (self-assembling dendrimers are considered as models for biological systems such as vesicles or micelles), cast films, colloids and nanoclusters, liquid crystals, biochemicals and pharmachemicals 20 and as chemiresistors .…”