Types Of Synthetic Polymers Research Articles

Regulation of in vitro gene expression using antisense oligonucleotides or antisense expression plasmids transfected using starburst PAMAM dendrimers.

Starburst polyamidoamine (PAMAM) dendrimers are a new type of synthetic polymer characterized by a branched spherical shape and a high density surface charge. We have investigated the ability of these dendrimers to function as an effective delivery system for antisense oligonucleotides and 'antisense expression plasmids' for the targeted modulation of gene expression. Dendrimers bind to various forms of nucleic acids on the basis of electrostatic interactions, and the ability of DNA-dendrimer complexes to transfer oligonucleotides and plasmid DNA to mediate antisense inhibition was assessed in an in vitro cell culture system. Cell lines that permanently express luciferase gene were developed using dendrimer mediated transfection. Transfections of antisense oligonucleotides or antisense cDNA plasmids into these cell lines using dendrimers resulted in a specific and dose dependent inhibition of luciferase expression. This inhibition caused approximately 25-50% reduction of baseline luciferase activity. Binding of the phosphodiester oligonucleotides to dendrimers also extended their intracellular survival. While dendrimers were not cytotoxic at the concentrations effective for DNA transfer, some non-specific suppression of luciferase expression was observed. Our results indicate that Starburst dendrimers can be effective carriers for the introduction of regulatory nucleic acids and facilitate the suppression of the specific gene expression.

Synthetic glycosyl polymers in isolation, characterization and immobilization of lectins

A review is given on preparative procedures and practical applications in the field of lectins of two types of synthetic polymers: (1) Glycosyl polyacrylamide derivatives - insoluble (cross-linked) and water-soluble (linear) - that are obtained by copolymerization of alkenyl glycosides and acrylamide, and (2) glycosyloxyethyl dimethacrylate copolymers prepared by glycosylation of the commercially available macroporous glycol methacrylate copolymer, Separon. Both types of copolymers are efficient affinity carriers for isolation of lectins. Separon derivatives can be used after partial periodate oxidation of the glycosyl groups for covalent coupling of lectins. Affinity carriers thus obtained can be employed in separation and purification of glycoproteins and other glycosylated macromolecules. Soluble glycosyl polyacrylamide derivatives are useful in precipitation of lectins and, in general, as synthetic model substances for studying interactions of lectins with sugar ligands.

Relative toxicity of pyrolysis gases from materials: Effects of chemical composition and test conditions

AbstractRelative toxicity test data on 270 materials are presented, based on test procedures developed at the University of San Francisco. The effects of chemical composition, using data on 13 types of synthetic polymers and eight types of fabrics, are discussed. Selected materials were evaluated using nine test conditions with the USF method, and using methods developed at the FAA Civil Aeromedical Institute, Douglas Aircraft Company and San Jose State University.

Functional monomers and polymers containing nucleic acid bases

AbstractIn order to prepare simply designed, nucleic acid analogs, a series of monomeric compounds containing purine and pyrimidine bases, such as vinyl, epoxy, dicarboxylic acid, propanediol and amino acid types, were synthesized. By polymerizing and polycondensing these monomers, different types of synthetic polymers with functional side groups were successfully obtained. As for the properties of the polymers prepared, base‐base interactions were studied in detail by measuring ultraviolet, NMR, and emission spectra. By utilizing these specific absorption characteristics, application for separating special base from base mixtures by chromatographic techniques is possible. High polymers with stereoregular structures were prepared which could be used as matrices for template polymerization using special base‐base interaction, as observed widely in the natural nucleic acid molecules. Further problems are considered and discussed.

Biological Properties of Poly-α- Amino Acids

Publisher Summary This chapter attempts to summarize the biological properties of poly-α-amino acids. The data already available indicate that these synthetic polypeptides may be of considerable value in the elucidation of the mode of action of known proteolytic enzymes, in the search for new proteolytic enzymes, and in the clarification of the inhibition of enzymes by macromolecules. It reviews that the close resemblance between the antibacterial and antiviral properties of basic polyamino acids with those of some natural peptides indicates that both the synthetic model compounds and the natural materials may act biologically by a similar mechanism. Also promising are the results obtained in the investigation of the immunological properties of synthetic poly-cu-amino acids and of polypeptidyl proteins, since they may contribute to the understanding of the chemical basis of the antigenicity of proteins. Finally, it is worth mentioning that water-soluble poly-a-amino acids represent one of the few types of synthetic polymers whose biological activity has been investigated in some detail. The extension of such studies to other synthetic water-soluble polymers may, perhaps, lead to the finding of new specific biological reagents. The chapter concludes that it should be stressed that the great value of synthetic poly-α-amino acids as protein models lies in their simplicity relative to the complexity of the natural proteins. Thus, many physical, chemical, and biological properties can be studied, as it were, in isolation by using such synthetic polypeptides. It should be remembered that this same simplicity imposes a limit on the usefulness of these substances, since certain properties, at least, of proteins may derive from a complexity of sequence and structure not found in the synthetic models.