Chromatography of nucleic acid digests on thin layers of cellulose impregnated with polyethyleneimine.
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ABSTRACT:
SUBMITTER: Southern EM
PROVIDER: S-EPMC1177002 | biostudies-other | 1971 Jul
REPOSITORIES: biostudies-other
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Project description:Purpose:Nucleic acid-based therapies are a promising therapeutic tool. The major obstacle in their clinical translation is their efficient delivery to the desired tissue. We developed a novel nanosized delivery system composed of conjugates of ?-tocopherol, polyethyleneimine, and polyethylene glycol (TPP) to deliver nucleic acids. Methods:We synthesized a panel of TPP molecules using different molecular weights of PEG and PEI and analyzed with various analytical approaches. The optimized version of TPP (TPP111 - the 1:1:1 molecular ratio) was self-assembled in water to produce nanostructures and then evaluated in diversified in vitro and in vivo studies. Results:Through a panel of synthesized molecules, TPP111 conjugate components self-assembled in water, forming globular shaped nanostructures of ~90 nm, with high nucleic acid entrapment efficiency. The polymer had low cytotoxicity in vitro and protected nucleic acids from nucleases. Using a luciferase-expressing plasmid, TPP111-plasmid nano-complexes were rapidly up-taken by cancer cells in vitro and induced strong transfection, comparable to PEI. Colocalization of the nano-complexes and endosomes/lysosomes suggested an endosome-mediated uptake. Using a subcutaneous tumor model, intravenously injected nano-complexes preferentially accumulated to the tumor area over 24 h. Conclusion:These results indicate that we successfully synthesized the TPP111 nanocarrier system, which can deliver nucleic acids in vitro and in vivo and merits further evaluation.
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Project description:The electrophoretic behaviour of oligodeoxynucleotides on ion-exchange papers was studied systematically with particular attention to applications in sequence analysis. Complex mixtures of larger oligonucleotides were fractionated by electrophoresis on cellulose acetate followed by t.l.c. on polyethyleneimine-cellulose. The behaviour of the oligonucleotides on polyethyleneimine-cellulose and on the two-dimensional system can provide a useful guide to their sequence. Detailed results from some of these experiments have been deposited as Supplementary Publication SUP 50031 (13 pages) at the British Library (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.
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Project description:1. Two methods for the fractionation of phosphatidylinositol into molecular species were developed. In addition to preserving the fatty acid moiety of the molecule, the first method preserves the phosphorus, and the second preserves both the phosphorus and inositol ring. 2. In the first method, phosphatidylinositol was oxidized with periodate and the products reacted with diazomethane. I.r. examination showed that the main product was identical with dimethylphosphatidic acid. Fractionation to molecular species was carried out on thin layers impregnated with silver nitrate. The fatty acid composition of the species was determined by gas-liquid chromatography, and their distribution in lamb liver phosphatidylinositol was studied by a method using [(3)H]methanol. 3. In the second method, phosphatidylinositol was acetylated under mild reaction conditions. The major product was the triacetylated derivative of this phospholipid. This was reacted with diazomethane and the methylated-triacetylated phosphatidylinositol was fractionated into molecular species on silver nitrate-impregnated thin layers. Solvent mixtures containing acetone and distilled chloroform were found most suitable for this purpose. The fatty acid composition of the molecular species was determined by g.l.c., and their distribution in lamb liver phosphatidylinositol was studied by a method using [1-(14)C]acetic anhydride during the acetylation reaction. 4. Results from both methods agree fairly well. The most predominant species of lamb liver phosphatidylinositol is the monoenoic (60%) followed by the tetraenoic (17%). The di- and tri-enoic species existed as minor components.
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Project description:After combined pancreatic and T(1) ribonuclease treatment of RNA, a characteristic series of products of the type A(n)N are obtained, where N can be any of the four ribonucleosides. Depending on whether phosphatase treatment is used before the addition of labelled phosphate at the 5'-terminus with bacteriophage phosphokinase, the labelled oligonucleotides obtained may or may not possess a phosphate group at the 3'- as well as the 5'-end. The behaviour of these characteristic products after electrophoresis on cellulose acetate strips followed by chromatography on polyethyleneimine-cellulose thin-layer plates was examined.
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Project description:Among the large number of promising two-dimensional (2D) atomic layer crystals, true metallic layers are rare. Using combined theoretical and experimental approaches, we report on the stability and successful exfoliation of atomically thin "gallenene" sheets on a silicon substrate, which has two distinct atomic arrangements along crystallographic twin directions of the parent α-gallium. With a weak interface between solid and molten phases of gallium, a solid-melt interface exfoliation technique is developed to extract these layers. Phonon dispersion calculations show that gallenene can be stabilized with bulk gallium lattice parameters. The electronic band structure of gallenene shows a combination of partially filled Dirac cone and the nonlinear dispersive band near the Fermi level, suggesting that gallenene should behave as a metallic layer. Furthermore, it is observed that the strong interaction of gallenene with other 2D semiconductors induces semiconducting to metallic phase transitions in the latter, paving the way for using gallenene as promising metallic contacts in 2D devices.
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