Enhancing ssDNA stability at acidic pH by encapsulation for the usage as DNA marking system

The usage of synthetic single-strand DNA (ssDNA) as an invisible barcode is critical for products, which are exposed to DNA damaging influences during their production or handling (ultraviolet light, acidic conditions, and high temperatures). Encapsulation may protect ssDNA against hydrolytic attack under acidic conditions. This assumption was proved by embedding ssDNA into a spherical hydrogel matrix of polyacrylamide and coating it with a crosslinked polystyrene shell. After acidic treatment of these capsules, the ssDNA stability was measured by detecting the amplification ratio over time with quantitative real-time polymerase chain reaction and calculating the apparent rate constant and apparent half-life. The results of the quantitative detection of ssDNA damage demonstrated that enhancing ssDNA stability by encapsulation with crosslinked polystyrene is possible. Such a potential application may be used in all fields of traceability and of combating counterfeiting, where protection of DNA against environmental influences is needed, for example, as safe marking system for paper, biomaterials, textiles, or leather

Mit Kohlenhydrat-Derivaten additivierte Gelatinezusammensetzungen

DE 102008059857 A1 UPAB: 20100714 NOVELTY - Composition (A) comprises: gelatin; and polysaccharide derivatives (I) and (II), as additives. DETAILED DESCRIPTION - Composition (A) comprises: gelatin; and polysaccharide derivatives of formulae (I) and (II), as additives. D = -CH2OR1, -CH2O-(CH2)n-COOR1, -CH2O-(CH2)n-COOR2, -CH2O-(CH2)m-OR1, -COOR1 or -COOR2; A = -O-(CH(R1))n-E, -O-C(O)-(CH2)n-CH3, -O-C(O)-(CH2)n-C(O)-(OCH2CH2)n-OR1 or OH (for the case that at least a part of the residue D is not -CH2OH); n = 1-24; E = -OR1, -N+(R1)2, -N+(R1)3/X-, -COOR2, -SO3R2 or 6-18C aryl-SO3R2; X- = negatively charged counter ion; R2 = H or Y+; Y+ = positively charged counter ion; R1 = H, 1-12C alkyl, 2-12C alkenyl, 2-12C alkynyl, 7-18C aralkyl, 6-18C aryl, 6-18C heteroaryl and/or -C(O)-(CH2)n-CH3; m = not defined; a/(a+b) = 0.1-1; B1 = -N(R1)-(CH(R1))n-E, -N-C(O)-(CH2)n-CH3, -N-C(O)-(CH2)n-C(O)-(OCH2CH2)n-OR1, -N+(R1)3/X- or a heterocyclic group of formula (a); c/(c+d+e) = 0.01-1; d/(c+d+e) = 0-0.4; and e/(c+d+e) = 0-0.99. Where in (I) and (II), underlying monomeric saccharide units in any order and alpha -1,4- or beta -1,4 can glycosidically linked to one another. USE - (A) is useful: in molded body, medical technology, packaging for industrial purposes, medical devices, and food and pharmaceuticals; as surface coatings, biocidal coatings, cell growth promoting material, a flat implant material in the form of nonwovens or films, an additive in adhesives for medical and technical purposes, an additive in food preparations, a matrix material for cell culture and tissue engineering, a coating for medicinal suture materials and textile fibers for clothing and technical purposes; for capsules, producing hemostatic sponges, and coating paper, foil, textiles and other support materials for medical and technical applications (all claimed). ADVANTAGE - (A) is biocompatible and has improved mechanical properties such as melting point, viscosity, gel strength and solubility

A new marking system for leather based on encapsulated DNA

The use of synthetic DNA as a marking system is a new traceability concept in the leather industry, especially for supplier and batch tracing. DNA is outstandingly suited for the usage as a marking system because of its code diversity, invisibility and doubtlessness. However, DNA labeling is a great challenge for products exposed to DNA damaging influences during their production, such as acidic pH, elevated temperatures in combination with high humidity or sunlight radiation. Leather is such a product. We attached single-strand DNA (ssDNA) to hydroxyapatite and enhanced the stability of these DNA particles by encapsulation in polystyrene-codivinylbenzene (PS-DVB) microcapsules. Furthermore, the ssDNA containing microcapsules were improved with functional groups on the surface of the capsule to irreversibly attach them to the collagen matrix of leather by chrome tanning. Laboratory scale tests using acidic conditions as well as elevated temperatures in the presence of high humidity showed that the stability of the leather marking system was enhanced. Marking trials were conducted in crust leathers, and the light fastness of these labeled crusts were tested. The results indicate that encapsulated DNA-hydroxyapatite-particles are more stable at sunlight radiation than non-encapsulated DNA. These marking trials showed that the system could be a suitable leather marking system in the leather industry to establish a powerful supplier and batch tracing

Novel polyelectrolytes with regular structure-synthesis, properties and applications

Amphiphilic surface-active vinyl monomers alkyl [2(methacryloyloxy)ethyl]dimethylammonium bromides, where alkyl is butyl or dodecyl have been investigated with respect to their polymerization behavior in the presence of various anionic initiators (Bu2Mg, tert-BuOK, calcium amide alkoxide). In most cases, the products consist of a low-molecular-weight fraction (Mw up to 5000) and a high-molecular-weight fraction (Mw up to 120 000). Block copolymers of the quaternary ammonium monomers with ethylene oxide show associative behavior in aqueous solutions

Flocculation efficiency of reacetylated water soluble chitosan versus commercial chitosan

In this work, the flocculation efficiency of reacetylated chitosans were compared with those of commercially available chitosans. The flocculation properties were investigated in dispersion of clay by means of turbidity measurements, colloid titration and measurements of the floc size. Reacetylated chitosan dissolves in deionized water without any additives and exhibits good flocculation properties like a wider flocculation window but a higher amount of polymer. For commercial chitosan lower amounts of polymer were required for the flocculation of clay dispersion. Flocculation with commercial chitosan is possible even in basic range

Cationic flocculants carrying hydrophobic functionalities: Applications for solid/liquid separation

The flocculation behaviors of three series of polycations with narrow molecular weight distributions carrying hydrophobic substituents on their backbones [poly(N-vinylbenzyl-N,N,N-trimethylammonium chloride), poly(N-vinylbenzyl-N,N-dimethyl-N-butylammonium chloride), and poly(N-vinylbenzylpyridinium chloride)] were investigated in dispersions of monodisperse polystyrene latexes and kaolin. Apparently, the charge density of the polycations decreases with increasing substituent hydrophobicity and increasing molecular weight of the polyelectrolytes. The necessary amount of flocculant for phase separation in dispersions with high substrate surface charge densities increases with increasing hydrophobicity of the polyelectrolyte. Nevertheless, the introduction of hydrophobic functionalities is beneficial, resulting in a substantial broadening of the range between the minimum and maximum amounts of flocculant necessary for efficient flocculation (flocculation window). An increase in ionic strength supports this effect. When the substrate has a low charge density, the hydrophobic interactions play a much more significant role in the flocculation process. Here, the minimum efficient doses remained the same for all three polyelectrolytes investigated, but the width of the flocculation window increased as the polycation hydrophobicity and the molecular weight increased. The necessary amount of flocculant increased with an increase in particle size at constant solid content of the dispersion, as well as with a decreasing number of particles at a constant particle size