The biological synthesis of nanoparticles is an ecological alternative to the physical and chemical method. The biological method is considered to be safe, cost effective, sustainable and not requiring any special preparation techniques. In chemical nanosynthesis for medical practice, biological coatings should be attached to the nanoparticles, in order to cut their toxicity. This phase can be skipped using the methods of biosynthesis of nanoparticles through the cyanobacterium Spirulina platensis, which make the nanoparticles more biocompatible. The study of biosynthesis of silver nanoparticles trough spirulina biomass showed the accumulation of silver nanoparticles over 24 hours of contact of the biomass with silver nitrate solution (Fig 1, a). Biochemical changes in Spirulina platensis biomass during the nanosynthesis have manifested themselves by a decrease of protein content by 22.7% in the first 24 hours of the reaction. Therefore biomass degradation is minimal.