Distinguishing the sources of silica nanoparticles by dual isotopic fingerprinting and machine learning

Abstract

One of the key shortcomings in the field of nanotechnology risk assessment is the lack of techniques capable of source tracing of nanoparticles (NPs). Silica is the most-produced engineered nanomaterial and also widely present in the natural environment in diverse forms. Here we show that inherent isotopic fingerprints offer a feasible approach to distinguish the sources of silica nanoparticles (SiO 2 NPs). We find that engineered SiO 2 NPs have distinct Si–O two-dimensional (2D) isotopic fingerprints from naturally occurring SiO 2 NPs, due probably to the Si and O isotope fractionation and use of isotopically different materials during the manufacturing process of engineered SiO 2 NPs. A machine learning model is developed to classify the engineered and natural SiO 2 NPs with a discrimination accuracy of 93.3%. Furthermore, the Si–O isotopic fingerprints are even able to partly identify the synthetic methods and manufacturers of engineered SiO 2 NPs.

Single-particle ICP-TOFMS with online microdroplet calibration for the simultaneous quantification of diverse nanoparticles in complex matrices

“…10,12 Multi-element fingerprinting provides a means to discover, identify, and quantify NP sub-classes, and, together with multi-isotope fingerprinting, is an emerging area of research in environmental nanoparticle analysis. 10,18,47,48 With multi-elemental sp-ICP-TOFMS, event concurrency analysis is a straightforward approach to identify multi-element correlations even within sub-populations of a given NP type and is especially wellsuited to identification of low-abundance multi-element NPs.…”

Emerging investigator series: automated single-nanoparticle quantification and classification: a holistic study of particles into and out of wastewater treatment plants in Switzerland

“…This limitation might be overcome by using machine learning approaches. 25,53 An alternative approach is to evaluate sub-clusters within our analysis. For example, in Fig.…”

Insights on toxicity, safe handling and disposal of silica aerogels and amorphous nanoparticles

“…43,44 Apart from crystalline silica (CS), which is one of the main components in the Earth's crust (in the forms of αand β-quartz, α-tridymite, αand β-cristobalite, keatite, coesite, and stishovite), engineered or synthetic amorphous silica (SAS) nanoparticles are among the most produced NPs worldwide for construction materials, industrial and consumer products. 33,45,46 Depending on the method used for the synthesispyrogenic, precipitation, solgelthree different SAS nanomaterials are obtained, namely fumed silica, precipitated silica and colloidal silica. 45,46 Moreover, with the explosion of the nanomedicine field, mesoporous silica (MS) and organosilica NPs have also been largely synthetized and studied for drug delivery, imaging and biosensor applications due to their good biocompatibility and superior loading properties in comparison with the crystalline and amorphous silica.…”

“…33,45,46 Depending on the method used for the synthesispyrogenic, precipitation, solgelthree different SAS nanomaterials are obtained, namely fumed silica, precipitated silica and colloidal silica. 45,46 Moreover, with the explosion of the nanomedicine field, mesoporous silica (MS) and organosilica NPs have also been largely synthetized and studied for drug delivery, imaging and biosensor applications due to their good biocompatibility and superior loading properties in comparison with the crystalline and amorphous silica. 47 SAS NPs are of utmost interest when searching for health or environmental effects of silica aerogels, for the herein described reasons.…”