Investigation into the Potential Migration of Nanoparticles from Laponite-Polymer Nanocomposites

In this study, the migration potential of laponite, a small synthetic nanoclay, from nanocomposites into foods was investigated. First, a laponite/ethylene vinyl acetate (EVA) masterbatch was compounded several times and then extruded into thin low-density polyethylene (LDPE) based films. This way, intercalation and partial exfoliation of the smallest type of clay was achieved. Migration of laponite was investigated using Asymmetric Flow Field-Flow Fractionation (AF4) with Multi-Angle Laser Light Scattering (MALLS) detection. A surfactant solution in which laponite dispersion remained stable during migration test conditions was used as alternative food simulant. Sample films with different loadings of laponite were stored for 10 days at 60 °C. No migration of laponite was found at a limit of detection of 22 µg laponite per Kg food. It can be concluded that laponite (representing the worst case for any larger structured type of clay) does not migrate into food once it is incorporated into a polymer matrix.

Download Full-text

Comparison of the Performances of Two Aptamers on a Colorimetric Assay for the Quantification of Fumonisin B1

Proceedings ◽

10.3390/iecb2020-07069 ◽

2020 ◽

Vol 60 (1) ◽

pp. 19

Author(s):

Vicente Antonio Mirón-Mérida ◽

Yadira González-Espinosa ◽

Yun Yun Gong ◽

Yuan Guo ◽

Francisco M. Goycoolea

Keyword(s):

Limit Of Detection ◽

Colorimetric Assay ◽

Fusarium Verticillioides ◽

Fumonisin B1 ◽

Detection Methods ◽

Field Flow Fractionation ◽

Asymmetric Flow ◽

Subsequent Addition ◽

Selection Of ◽

Analytical Detection

Fumonisin B1 (FB1), a mycotoxin commonly produced by Fusarium verticillioides and classified as a group 2B hazard, has been identified in various food products; hence, sensitive and rapid analytical detection methods are needed. Since the first reported aptamer (96 nt ssDNA) for the highly specific molecular recognition of FB1, only 30 aptamer-based biosensors have been published. A critical point, yet commonly overlooked during the design of aptasensors, is the selection of the binding buffer. In this work, a colorimetric assay was designed by incubating a folded aptamer with FB1 and the subsequent addition of gold nanoparticles (AuNPs). The changes in the aggregation profile of AuNPs by a 40 nt aptamer and a 96 nt aptamer were tested after the addition of FB1 under different buffer conditions, where the incubation with Tris-HCl and MgCl2 exhibited the most favorable performances. The assay with the longest aptamer was specific to FB1 and comparable to other aptasensors with a limit of detection (LOD) of 3 ng/mL (A650/520 ratio). Additionally, the application of asymmetric-flow field-flow fractionation (AF4) with multidetection allowed for the analysis of the peak area (λ) and multi-angle light scattering (MALS) with LODs of up to the fg/mL level.

Download Full-text

The Influence of Temperature on the Characterization of Water-Soluble Polymers Using Asymmetric Flow Field-Flow-Fractionation Coupled to Multiangle Laser Light Scattering

Analytical Chemistry ◽

10.1021/ac991205x ◽

2000 ◽

Vol 72 (16) ◽

pp. 3896-3901 ◽

Cited By ~ 20

Author(s):

Christer Viebke ◽

Peter A. Williams

Keyword(s):

Laser Light ◽

Laser Light Scattering ◽

Water Soluble ◽

Field Flow Fractionation ◽

Asymmetric Flow ◽

Water Soluble Polymers ◽

Soluble Polymers ◽

Influence Of Temperature On ◽

Multiangle Laser Light Scattering

Download Full-text

Aptamer–Target–Gold Nanoparticle Conjugates for the Quantification of Fumonisin B1

Biosensors ◽

10.3390/bios11010018 ◽

2021 ◽

Vol 11 (1) ◽

pp. 18

Author(s):

Vicente Antonio Mirón-Mérida ◽

Yadira González-Espinosa ◽

Mar Collado-González ◽

Yun Yun Gong ◽

Yuan Guo ◽

...

Keyword(s):

Gold Nanoparticles ◽

Limit Of Detection ◽

Fumonisin B1 ◽

Sample Pretreatment ◽

Good Alternative ◽

Field Flow Fractionation ◽

Asymmetric Flow ◽

High Importance ◽

Site Analysis ◽

Induced Aggregation

Fumonisin B1 (FB1), a mycotoxin classified as group 2B hazard, is of high importance due to its abundance and occurrence in varied crops. Conventional methods for detection are sensitive and selective; however, they also convey disadvantages such as long assay times, expensive equipment and instrumentation, complex procedures, sample pretreatment and unfeasibility for on-site analysis. Therefore, there is a need for quick, simple and affordable quantification methods. On that note, aptamers (ssDNA) are a good alternative for designing specific and sensitive biosensing techniques. In this work, the assessment of the performance of two aptamers (40 and 96 nt) on the colorimetric quantification of FB1 was determined by conducting an aptamer–target incubation step, followed by the addition of gold nanoparticles (AuNPs) and NaCl. Although MgCl2 and Tris-HCl were, respectively, essential for aptamer 96 and 40 nt, the latter was not specific for FB1. Alternatively, the formation of Aptamer (96 nt)–FB1–AuNP conjugates in MgCl2 exhibited stabilization to NaCl-induced aggregation at increasing FB1 concentrations. The application of asymmetric flow field-flow fractionation (AF4) allowed their size separation and characterization by a multidetection system (UV-VIS, MALS and DLS online), with a reduction in the limit of detection from 0.002 µg/mL to 56 fg/mL.

Download Full-text

Limitations of Nanoparticles Size Characterization by Asymmetric Flow Field‑Fractionation Coupled with Online Dynamic Light Scattering

Chromatographia ◽

10.1007/s10337-020-03997-7 ◽

2021 ◽

Author(s):

Francesco Giorgi ◽

Judith M. Curran ◽

Douglas Gilliland ◽

Rita La Spina ◽

Maurice Whelan ◽

...

Keyword(s):

Light Scattering ◽

Dynamic Light Scattering ◽

Flow Field ◽

Field Flow Fractionation ◽

Asymmetric Flow ◽

Uv Detector ◽

Elution Time ◽

On Line ◽

Real Size ◽

Flow Fractionation

AbstractThe development of reliable protocols suitable for the characterisation of the physical properties of nanoparticles in suspension is becoming crucial to assess the potential biological as well as toxicological impact of nanoparticles. Amongst sizing techniques, asymmetric flow field flow fractionation (AF4) coupled to online size detectors represents one of the most robust and flexible options to quantify the particle size distribution in suspension. However, size measurement uncertainties have been reported for on-line dynamic light scattering (DLS) detectors when coupled to AF4 systems. In this work we investigated the influence of the initial concentration of nanoparticles in suspension on the sizing capability of the asymmetric flow field-flow fractionation technique coupled with an on-line dynamic light scattering detector and a UV–Visible spectrophotometer (UV) detector. Experiments were performed with suspensions of gold nanoparticles with a nominal diameter of 40 nm and 60 nm at a range of particle concentrations. The results obtained demonstrate that at low concentration of nanoparticles, the AF4-DLS combined technique fails to evaluate the real size of nanoparticles in suspension, detecting an apparent and progressive size increase as a function of the elution time and of the concentration of nanoparticles in suspension.

Download Full-text