author = "Montanheiro, Thais L. A. and Montagna, Larissa S. and Farias, 
                         Marcelo A. de and Magalh{\~a}es, J{\'e}ssica A. and Tada, Dayane 
                         B. and Passador, F{\'a}bio R. and Machado, Jo{\~a}o Paulo Barros 
                         and Lemes, Ana Paula",
          affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {Laborat{\'o}rio Naiconal de 
                         Nanotecnologia} and {Universidade de S{\~a}o Paulo (USP)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Universidade de S{\~a}o Paulo (USP)}",
                title = "Cytotoxicity and physico-chemical evaluation of acetylated and 
                         pegylated cellulose nanocrystals",
              journal = "Journal of Nanoparticle Research",
                 year = "2018",
               volume = "20",
               number = "8",
                pages = "e206",
                month = "Aug.",
             keywords = "Cellulose nanocrystal . Acetylation . Pegylation . Nanoparticle . 
                         Functionalization . Hydrophilicity. Cell proliferation.",
             abstract = "The high hydrophilicity of cellulose nanocrystals (CNC) may result 
                         in poor dispersion in some matrices and solvents. So in this work, 
                         two different methodologies were used to reduce the hydrophilicity 
                         of CNC. In the first methodology, CNC were acetylated (CNC-Ac) in 
                         a mixture of acetic and hydrochloric acid, and in the second 
                         methodology, polyethylene glycol (PEG) was adsorbed onto CNC 
                         surface (CNC-PEG) under stirring in aqueous solution. CNC obtained 
                         by both methods were characterized by transmission electron 
                         microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction 
                         (XRD), dynamic light scattering (DLS), zeta potential, and 
                         thermogravimetric analysis (TGA). Images of TEM showed that the 
                         intrinsic morphology of cellulose was preserved after both 
                         treatments. FTIR confirmed acetylation reaction by the presence of 
                         a new band at 1732 cm\−1 (acetate groups) and the 
                         consumption of OH groups. XRD showed a reduction in the 
                         crystallinity index for both applied methodologies. DLS showed 
                         reduced stability in water for CNC-Ac and CNC-PEG. Values of zeta 
                         potential changed after acetylation, from \− 45 mV (CNC) to 
                         \− 1 mV (CNC-Ac), and after adsorption of PEG, to \− 
                         26.7 mV (CNC-PEG). TGA showed a reduction in the thermal stability 
                         after both treatments and a change in the main degradation 
                         behavior for CNC-PEG. MTT assays showed that both proposed 
                         functionalizations induce cell proliferation, being even more 
                         evident for acetylation because, in addition to viability increase 
                         with time, it increased with the sample concentration.",
                  doi = "10.1007/s11051-018-4306-3",
                  url = "http://dx.doi.org/10.1007/s11051-018-4306-3",
                 issn = "1388-0764",
             language = "en",
           targetfile = "montanheiro_cytotoxicity.pdf",
        urlaccessdate = "27 nov. 2020"