An innovative approach for the treatment of diabetic and venous ulcers, characterized by a difficult healing process and therefore at potential risk of infection and therefore of hospitalization and amputation of the limb, is represented by the local administration of "bioactive" factors through the use of synthetic and/or biological matrices that allow a gradual and controlled release in order to obtain a better and faster healing. The object of the present invention relates to the method for the preparation of an advanced dressing, in which the bioactive factors, in the specific case platelet lysate (PL) obtained from umbilical cord blood (CB) [CB-PL] and plasminogen (PLG), are both loaded into the dressing at the time of manufacture. A biodegradable dressing is thus obtained in which CB-PL and PLG are loaded into a cross-linked fibrin matrix obtained through a three (3) way spray deposition process in which a solution of fibrinogen, one of thrombin and one containing the “bioactive” factors (CB-PL and / or PLG), are sprayed separately, but at the same time, in a convergent way on a rotating cylindrical support. The CB-PL and PLG loaded fibrin dressing was manufactured using spray technology. The spray technology used made use of an equipment present in the "Laboratory of Biomaterials and Regenerative Medicine" of IFC-CNR and called "Advanced Spray-Machine". This particular equipment is equipped with a system of three converging jet spray guns which allows the solute contained in three different solutions to be deposited, by means of a separate spray - but at the same time, on a rotating cylindrical mandrel. With this technology it was possible to obtain the formation of a consistent layer of cross-linked fibrin (in other words mechanically resistant) on a rotating mandrel.
The patent idea consists in the administration of "bioactive" factors through the use of a patch of elastic and mechanically consistent fibrin that can be easily cut and applied to a wound, allowing the local and controlled release of bioactive factors at the site of the injury. The technical problem that the invention solves concerns the preparation of an advanced dressing, in which the bioactive factors, in the specific case platelet lysate (PL) obtained from umbilical cord blood (CB) [CB-PL] and/or plasminogen (PLG), are both loaded into the dressing at the time of manufacture. With this method, a biodegradable dressing is obtained in which CB-PL and/or PLG are loaded into a cross-linked fibrin patch obtained by a three (3) way spray deposition process in which a solution of fibrinogen, one of thrombin and one containing the “bioactive” factors (CB-PL and/or PLG), are sprayed separately, but at the same time, in a convergent way on a rotating cylindrical support. The main advantage of the method described, that is the separate deposition of fibrinogen on a rotating support and the simultaneous deposition of thrombin (spray at low flow in order to avoid dripping phenomena with consequent loss of material), is to allow a cross-linking of fibrinogen (which is transformed into fibrin) in thin sequential layers until the formation of a certain thickness of fibrin. All the intimately cross-linked layers contribute to the formation of an elastic and mechanically resistant patch of fibrin only, which can be applied and adapted as easily to a wound as any other dressing.
Italy; PCT