The present invention relates to a sampling instrument adapted for taking a sample in situ and in vivo or taking a sample ex vivo of a target tissue or body structure, in a maximum quantity of less than 10−6 g, the instrument comprising an elongated active member (10) with a distal operative end (11) having at least one retaining surface (12) arranged for contacting directly the target tissue or body structure, capturing and retaining molecules of the target tissue or body structure thereto.
