Easily Adjusting Capillary Flow Rates on Nitrocellulose Membranes by a Household Laminator

Capillary flow rate control is interesting for biosensors based on nitrocellulose membranes. This paper introduces a method to control capillary flow rates on nitrocellulose membranes by simply pressing the nitrocellulose membranes using a household laminator. By applying pressure on nitrocellulose membranes, we can easily change the thickness of the nitrocellulose membrane and therefore change the pore size of the porous structure. We also notice that the pressure can break some nitrocellulose fibers. We investigate the influence by measuring the capillary flow rates on nitrocellulose membranes treated by different pressure, and also check their capacity of water absorption. We find that capillary flow rates decrease on nitrocellulose membranes with pressure treatment and the method can reduce the capillary flow rate by up to 42.3%. The water absorption capacity also decreases for nitrocellulose membranes with pressure treatment, and the maximum decrease is 44.6%. This method is promising in reducing the sample flow rates in biosensing devices made of nitrocellulose membranes.