The machine comprises a working station and a fixed bed disposed to the rear side of the working station. The nano-composite includes at least one copolymer chain having alkenyl monomer units and maleimide monomer units, and a nano-sized metal or inorganic crystal. The carrier may have a hydrophilic surface, and an amount of liquid medium is used to prevent agglomeration of the carrier. An optical assembly is used for directing along a common detection axis an intensity coming from said regions that would be otherwise out of sight.