The present invention provides methods, apparatuses and kits for determining the presence and the concentration of nanoparticles in a given area, solution or region via cellular uptake and/or adsorption monitored through laboratory equipment. For example, the present invention provides a method of quantifying one or more nanoparticles by incubating a nanoparticle solution comprising one or more nanoparticles with one or more cells; isolating the one or more cells; lysing the one or more cells to release a cell lysate; separating the cell lysate electrophoretically on a gel; digitizing the gel to form a gel image; quantifying the nanoparticle intensity in the gel image; and correlating the nanoparticle intensity to a cell-associated nanoparticle concentration.