Method for the preparation of crosslinked and optionally shaped tissue, in particular crosslinked and/or shaped biological tissue, with selective adaptation of the thickness, shape and/or flexibility of the tissue, for medical applications, in particular for use as a component of a medical implant, preferably a vascular implant, more preferably an artificial heart valve a left atrial appendage closure device, a pacemaker, a leadless pacemaker or a covered stent, wherein the method comprises at least the following steps: a) providing one or more tissue(s), preferably collagen containing biological tissue, more preferably pericardial tissue, comprising chemically and/or biochemically crosslinkable groups; b) providing at least one, preferably at least two, permeable material layers configured, optionally bonded to each other, to act as at least a support surface covering the tissue and/or as at least a perfectly fitting receiving pocket for the tissue; c) optional cutting of the tissue(s) to be crosslinked according to step a) by means of a suitable cutting instrument and/or a suitable cutting device; d) placing/arranging the tissue according to step a) or c) on, in or between the permeable material layer(s) according to step b); e) providing one or more pressure compensation layers, which are configured to partially or completely cover at least the tissue and the at least one or more permeable material layers as a support surface; f) optionally providing a container or receptacle suitable for chemical crosslinking; g) chemically crosslinking the tissue according to step d) with the addition of a suitable crosslinking agent, optionally within the container or receptacle according to step f), preferably over a total period of at least 4 hours to a maximum of 5 days; h) removal of the crosslinked and optionally shaped tissue according to step g); i) optional chemical post-crosslinking by means of a suitable crosslinking agent. a) providing one or more tissue(s), preferably collagen containing biological tissue, more preferably pericardial tissue, comprising chemically and/or biochemically crosslinkable groups; b) providing at least one, preferably at least two, permeable material layers configured, optionally bonded to each other, to act as at least a support surface covering the tissue and/or as at least a perfectly fitting receiving pocket for the tissue; c) optional cutting of the tissue(s) to be crosslinked according to step a) by means of a suitable cutting instrument and/or a suitable cutting device; d) placing/arranging the tissue according to step a) or c) on, in or between the permeable material layer(s) according to step b); e) providing one or more pressure compensation layers, which are configured to partially or completely cover at least the tissue and the at least one or more permeable material layers as a support surface; f) optionally providing a container or receptacle suitable for chemical crosslinking; g) chemically crosslinking the tissue according to step d) with the addition of a suitable crosslinking agent, optionally within the container or receptacle according to step f), preferably over a total period of at least 4 hours to a maximum of 5 days; h) removal of the crosslinked and optionally shaped tissue according to step g); i) optional chemical post-crosslinking by means of a suitable crosslinking agent.