An impact of ionic strength (0,001...10 mM) of low-molecular carboxylic acids on aggregation of engineered nanoparticles in water suspensions was considered in the paper. With the help of light dynamic scattering it has been shown that the increase of surfactant concentration 1) leads to stabilization of Al and Al[2]O[3] nanoparticles in sodium citrate solution, 2) has no significant effect on particles aggregation in sodium oxalate solution, and 3) provokes nanoparticles aggregation in sodium acetate solution. Experimental data allows revealing optimal conditions to create aggregation-sustainable hydrosols of biologically active nanoparticles.