Patent ID: 8686709

Claim:
An apparatus ( 100 ) for counting particles ( 7 , 7 â€², 7 â€³) in a fluid comprising: a substrate ( 101 ) having a first surface ( 102 ); a lid ( 107 ) having a second surface ( 111 ) facing the first surface ( 102 ); at least one spacer element ( 103 ) interposed between the substrate ( 101 ) and the lid ( 107 ) so as to maintain the first and the second surface ( 102 , 111 ) spaced from one another; a partition ( 105 ) with a plurality of through-openings ( 106 ) having nanometric size, the partition being interposed between said at least one spacer element ( 104 ) and said lid ( 107 ) so as to define at least one first chamber ( 109 ) between said partition and the lid and at least one second chamber ( 108 ) between said partition ( 105 ) and the substrate ( 101 ), the at least one first chamber and the at least one second chamber ( 108 , 109 ) being fluidically connected to one another through at least one of said openings ( 106 ); the substrate ( 101 ) having at least one first electrode ( 103 ) on the first surface ( 102 ) and the lid ( 107 ) having a second electrode ( 107 , 107 â€²), the said at least one first electrode ( 103 ) being configured so as to detect an electric signal associated to the passage of one of said particles ( 7 , 7 â€², 7 â€³) through one said through-opening ( 106 ) of said partition ( 105 ), wherein: said at least one spacer element ( 104 ) comprises a peripheral element which defines laterally said at least one second chamber ( 108 ); said at least one spacer element ( 104 ) comprises a separator ( 114 ) to separate the at least one second chamber ( 108 ) in a plurality of microchambers ( 108 â€²), each microchamber ( 108 â€²) being fluidically connected to the at least one first chamber ( 109 ) by at least one opening ( 106 ) of said partition ( 105 ); each microchamber ( 108 â€²) comprises a predetermined number of first electrodes ( 103 ) and a determined number of said openings, the number of said first electrodes ( 103 ) being greater than or equivalent to the number of said openings ( 106 ) included in said second chamber ( 108 ); and said at least one first electrode ( 103 ) is provided with at least one auxiliary focusing electrode ( 103 â€²) adapted to direct the particles of interest towards said opening ( 106 ) univocally associated to said first electrode ( 103 ).