Abstract: An electrophoresis device having a single-piece cartridge (10) filled with a suitable and optionally dyed gel (26) and made from a section of a hollow shape having two opposite open sides (20,22), one of which is sealed by a removable comb element (28) for forming imprints in the gel (26), while the other is sealed by a removable cover (36).

Abstract: A high security crypto-marking method for protecting valuable objects in which a target chemical compound suitable for subsequent detection by an appropriate detection means is applied to an object to be marked, wherein the method comprises the following operations:a) preparing a solution of a target nucleic acid having a sequence selected to form a marking pattern and possessing a selected degree of fluidity;b) incorporating a chosen quantity of the solution in each object of a class of objects to be marked;thereby making it possible, subsequently, and should the occasion arise, to perform the following operation:c) identifying or authenticating the object by using means for detecting the nucleic acid in order to reveal the marking.The invention can be used, where required, to provide irrefutable proof of ownership of an object in the event of theft, resale, or forgery.

Abstract: A method of staining a nucleic acid sequence which is fixed on a solid support is described wherein an enzymatic system which fixes this sequence is employed to detect it by non-radioactive labelling, the enzymatic system being subsequently reacted with chromogenic substrate to produce a colored product. A developer solution is used comprising a sulfur organic compound constituting the substrate which is adapted to be hydrolized by the enzyme to form an organic thiol, and a metallic compound, for example a gold compound. The metallic compound is soluble and stable in aqueous solution and can react with the organic thiol to form a metal-organic compound complex having a characteristic color which precipitates in situ, which metal-organic complex subsequently may be decolorized with a reducing agent to thus allow reuse of the solid support. A set, or kit, of reactants for carrying out the method also is disclosed.