Direct quantification of nanoparticle surface hydrophobicity

Abstract

Hydrophobicity is an important parameter for the risk assessment of chemicals, but standardised quantitative methods for the determination of hydrophobicity cannot be applied to nanomaterials. Here we describe a method for the direct quantification of the surface energy and hydrophobicity of nanomaterials. The quantification is obtained by comparing the nanomaterial binding affinity to two or more engineered collectors, i.e. surfaces with tuned hydrophobicity. In order to validate the concept, the method is applied to a set of nanoparticles with varying degrees of hydrophobicity. The technique described represents an alternative to the use of other methods such as hydrophobic interaction chromatography or water-octanol partition, which provide only qualitative values of hydrophobicity.

Deposition of environmentally relevant nanoplastic models in sand during transport experiments

“…An extended version, the XDLVO theory, includes the Lewis acid-base (hydrophobic) interaction energy (G AB ). This component has been carefully quantified using the method described by Valsesia et al (2018). It should be noted, however, that since DLVO and XDLVO theories assume that the particles are spherical, they cannot correctly determine the interaction energy of the asymmetrical and irregularly shaped NPT-Ps (Hotze et al, 2010 3 and full lines in Figure 2c).…”

“…where λ is the correlation length, chosen as 1.65 nm, according to Valsesia et al (2018), and h is the minimum distance of separation between the particle and the surface, taken as 0.158 nm. The acidbase potential ΔG AB is expressed as: The DLVO theory was modified by the SEI method described by Wu et al ( 2013) to understand the effect of NPT-P's nonspherical shape and their different orientations, described by the angle φ that is formed between the major axis of the particle and the collector surface (Bhattacharjee et al, 2000).…”

Unpredictable Nanoparticle Retention in Commonly Used Plastic Syringes Introduces Dosage Uncertainties That May Compromise the Accuracy of Nanomedicine and Nanotoxicology Studies

“…Besides the data presented here nothing similar is reported so far for in vitro testing of nanoparticles. However, a recent report dealing with the quantification of nanoparticle surface hydrophobicity shows that surfaces can be manipulated in a way to completely bind or repel nanoparticles (Valsesia et al, 2018). This means that binding problems may indeed occur during in vitro testing with nanoparticles, but it seems encouraging that “non-binding” lab-ware and syringes could become available if surface modifications can be implemented in an industrial production process of medical devices.…”

Biostimulation and toxicity: The magnitude of the impact of nanomaterials in microorganisms and plants

“…Hydrophobicity is thought to be highly relevant to define the biological impact of the NMs [74] since the hydrophobicity: hydrophilicity ratio of the surfaces of the NMs determines the interaction and adhesion with cell walls and membranes. In general, hydrophobic surfaces tend to adhere to other hydrophobic surfaces, and the same occurs with hydrophilic-hydrophilic [73] .…”