Objective: Polyelectrolyte adsorption in charge surface is nowadays extensively studied in industrial and medicine research. However, polyelectrolyte conformation is until now fully understood. Recently new nanometer structure, called nanoring have been observed after sequential adsorption of two polyelectrolytes on negatively charged surface. In this work we investigate the chemical and physical parameters controlling the formation of nanorings. Methods: Liquid cell is used to obtain in situ contact mode AFM images (Nanoscope IIIa, Digital Instruments SB, CA, USA). Poly(ethyleneimine) (PEI) and poly(sodium 4-styrenesulfonate) (PSS) (both Mw ≈7X104Da) at 1mg/ml and MES-TRIS NaCl 25mM buffer at pH 7.4 were used, all solutions are prepared with degassing ultra-pure water (Milli Q-Plus system, Millipore). After sequential adsorption of PEI and PSS (respectively) polyelectrolytes in a glass substrate characteristic nanoring structures are observed. Results: Two parameters are observed to be critical for the formation of nanorings, the filtration of solutions and the carbonate ions concentration in solution. Significant statistical difference between nanorings external diameter is observed after filtration with 0.45, 0.22 and 0.10 µm pore size (p=<0.001). We observed also statistical difference of nanorings size versus contact air of solutions. During time (3 to 24 hours) CO2 is adsorbed in solution as HCO3-2 and CO3- carbonate ions.Conclusion: Knowledge formation process of nanorings gives the possibility to produce polyelectrolyte nanorings of different sizes. Nanorings can be as pattern to form Quantum dots or to control calcium phosphate nucleation to develop of new biomaterials.Acknowledgments: This work was supported by SEP-CONACyT-ANUIES-ECOS France-Mexique PROMEP-UASLP

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