Morphological and Physicochemical Characterization of Agglomerates of Titanium Dioxide Nanoparticles in Cell Culture Media

Abstract

Titanium dioxide nanoparticles (TiO2NP) are possible carcinogenic materials (2B-IARC) and their toxicity depends on shape, size, and electrical charge of primary NP and on the system formed by NP media. The aim of this work was to characterize agglomerates of three TiO2NP by evaluating their morphometry, stability, and zeta potential (ζ) in liquid media and their changes with time. Sizes of agglomerates by dynamic light scattering (DLS) resulted to be 10–50 times larger than those obtained by digital image analysis (DIA) given the charged zone around particles. Fractal dimension (FD) was highest for agglomerates of spheres and belts in F12K, and in E171 in FBS media. E171 and belts increased FD with time. At time zero, using water as dispersant FD was larger for agglomerates of spheres than for of E171. Belts suspended in water had the smallest values of circularity (Ci) which was approximately unchanged with time. All dispersions hadζvalues around −30 mV at physiological pH (7.4) and dispersions of NP in water and FBS showed maximum stability (Turbiscan Lab analysis). Results help in understanding the complex NP geometry-size-stability relationships when performingin vivoandin vitroenvironmental-toxicity works and help in supporting decisions on the usage of TiO2NP.

In vitrodigestion of food grade TiO2(E171) and TiO2nanoparticles: physicochemical characterization and impact on the activity of digestive enzymes

“…In fact, the objects analysed in this study may have a fractal dimension, such as E171 in cell culture media. 50 The increased agglomeration during digestion has also been recently observed in digestive media, which were mainly based on phosphate buffer and containing uric acid and urea in the salivary phase. 51 Such agglomeration may explain the poor internalisation of TiO2 observed in vivo by humans 52 Besides, zeta potential values increased (Figure 3), i.e.…”

Possible Adverse Effects of Food Additive E171 (Titanium Dioxide) Related to Particle Specific Human Toxicity, Including the Immune System

“…Complex biological and physiological cell culture media can contain electrolytes, lipids, or proteins, and vary in their pH values, which potentially alters initial particle characteristics. Examination of the state of aggregation and colloidal stability in a time-based manner, could therefore provide valuable insights into particle behavior, help to better understand particle uptake, and eventually lead to adjustments regarding dosimetry [ 37 , 152 ]. As E171 is brought into commerce in different crystal forms, additional information is needed in which crystal form it is manufactured and how this may affect toxicity.…”

Removal of Methylene Blue from Aqueous Solutions by Using Nance (Byrsonima crassifolia) Seeds and Peels as Natural Biosorbents

“…Images of seeds and peels before and after methylene blue adsorption were obtained by scanning electron microscopy (SEM) (Quanta FEG 3D) (500x, 1500x, and 5000x, 15 kV, 26 pixels/nm 2 ) [32]. Fractal dimension (FD) was obtained by using ImageJ v. 1.53g software (National Institutes of Health, USA).…”