Abstract: The present invention relates to an in vitro or ex vivo method of preparing a cell-free composition, said method comprising or consisting of (a) subjecting cells to stress; and (b) collecting factors produced, preferably secreted by said cells when subjected to said stress, thereby obtaining said cell-free composition; wherein said cells are comprised in or form at least one first carrier and said collecting is effected by means of at least one second carrier which second carrier(s) is/are cell-free and concomitantly present with and spatially distinct from said first carrier; and said collecting is effected using a device comprising or consisting of (i) said first carrier(s) which first carrier(s) comprise(s) said cells or is/are suitable to hold said cells; (ii) said second carrier(s) which is cell-free; and (iii) means of subjecting said cells in said first carrier to stress; wherein first carrier(s) and second carrier(s) are positioned such that factors secreted by said cells when subjected to stress are