Method of producing a sealing means in a microfluidic structure and a microfluidic structure comprising such sealing means

DETAILED DESCRIPTION The object of the present invention is to provide a solution to this sealing problem in order to permit inter alia a two-part microfluidic system device of the above mentioned type to be produced in a hard or non-resilient material such as silicon.
In accordance with the present inventive concept an efficient sealing strip may be accomplished by moulding into a channel structure recessed into one of the two plate members to be combined, a resilient sealing material such that the top part of the sealing strip formed projects above the groove structure edges, and has such a configuration in the upper part of the groove structure that, when the sealing strip is compressed by pressing of the two plate members against each other, the deformed material is capable of being completely accommodated in the upper part of the groove structure.
Such a sealing strip may be produced in the necessary small size and will permit complete contact between the non-recessed areas of the plate members while simultaneously providing efficient leakage-proof sealing between areas on either sides of the sealing strip.
A sealing strip produced in the described manner will be excellently useful for microfluidic purposes, and particularly when very small channel heights are involved.
Thus, in one aspect the present invention provides a method for producing a leakage-proof sealing means in a microfluidic channel assembly comprising first and second flat surface members which when pressed against each other define at least part of a microfluidic channel system between them, which method comprises the steps of (i) recessing at least one groove structure into the flat surface of the first member; (ii) providing a counter mould, the mould surface of which has at least one groove structure or at least one ridge structure, optionally in combination, said structure or structures having a corresponding extension as, but a smaller width than the groove structure or structures of the first member; (iii) applying the counter mould against the first member such that a mould cavity or cavities are defined by the groove structure or structures of the first member with the counter mould surface portions comprising said groove or ridge structure or structures; (iv) introducing, e