The invention provides an apparatus and a method of processing a biological and/or chemical sample in a liquid droplet. The apparatus comprises a processing compartment, which is defined by a reservoir and an immobilization member. The processing compartment is further adapted to accommodate a medium, which is immiscible with the liquid droplet, and of a lower surface energy than the liquid of the liquid droplet. The reservoir is defined by a circumferential wall and a base. The immobilization member is arranged within the reservoir and comprises a surface that is patterned in such a way that it comprises at least one predefined immobilization area. The predefined immobilization area within the patterned surface is of a higher surface energy than the medium. The liquid droplet is disposed onto the predefined immobilization area, whereby the liquid droplet is immobilized thereon via hydrophilic-hydrophilic or hydrophobic-hydrophobic interactions.