Interactions of coated-gold engineered nanoparticles with aquatic higher plant Salvinia minima baker

Loading...
Thumbnail Image

Authors

Mahaye, Ntombikayise
Thwala, Melusi
Musee, Ndeke

Journal Title

Journal ISSN

Volume Title

Publisher

MDPI

Abstract

The study investigated the interactions of coated-gold engineered nanoparticles (nAu) with the aquatic higher plant Salvinia minima Baker in 2,7, and 14 d. Herein, the nAu concentration of 1000 g/L was used; as in lower concentrations, analytical limitations persisted but >1000 g/L were deemed too high and unlikely to be present in the environment. Exposure of S. minima to 1000 g/L of citrate (cit)- and branched polyethyleneimine (BPEI)-coated nAu (5, 20, and 40 nm) in 10% Hoagland’s medium (10 HM) had marginal effect on biomass and growth rate irrespective of nAu size, coating type, or exposure duration. Further, results demonstrated that nAu were adsorbed on the plants’ roots irrespective of their size or coating variant; however, no evidence of internalization was apparent, and this was attributed to high agglomeration of nAu in 10 HM. Hence, adsorption was concluded as the basic mechanism of nAu accumulation by S. minima. Overall, the long-term exposure of S. minima to nAu did not inhibit plant biomass and growth rate but agglomerates on plant roots may block cell wall pores, and, in turn, alter uptake of essential macronutrients in plants, thus potentially affecting the overall ecological function.

Description

Supplementary Materials: Equation (S1): Calculation of ζ potentials using Smoluchowski equation, Equation (S2): Calculation of ionic strength (IS) of the exposure medium, Figure S1: TEM images of nAu (a) 5 nm-Cit, (b) 20 nm-Cit, (c) 40 nm-Cit, (d) 5 nm-BPEI, (e) 20 nm-BPEI, (f) and 40 nm-BPEI, Table S1: Composition of Hoagland’s medium, Table S2: Mean sizes (nm) of nAu obtained using TEM, Figure S2: Particle size distribution of nAu at 1000 µg/L in 10% Hoagland’s medium measured using Dynamic Light Scattering technique (a) 5 nm Cit-nAu, (b) 20 nm Cit-nAu, (c) 40 nm Cit-nAu, (d) 5 nm BPEI-nAu, (e) 20 nm BPEI-nAu, and (f) 40 nm BPEI-nAu, Figure S3: Hydrodynamic diameters of nAu in de-ionized water and 10% Hoagland’s medium tracked using Dynamic Light Scattering technique over 48 h; (a) 5 nm Cit-nAu, (b) 20 nm Cit-nAu, (c) 40 nm Cit-nAu, (d) 5 nm BPEI-nAu, (e) 20 nm BPEI-nAu, and (f) 40 nm BPEI-nAu, Figure S4: Zeta potentials of nAu in de-ionized water and 10% Hoagland’s medium obtained using Dynamic Light Scattering technique over 48 h; (a) 5 nm Cit-nAu, (b) 20 nm Cit-nAu, (c) 40 nm Cit-nAu, (d) 5 nm BPEI-nAu, (e) 20 nm BPEI-nAu, and (f) 40 nm BPEI-nAu, Figure S5: UV-vis spectrum of nAu in de-ionized water as a function of time; (a) 5 nm Cit-nAu, (b) 20 nm Cit-nAu, (c) 40 nm Cit-nAu, (d) 5 nm BPEI-nAu, (e) 20 nm BPEI-nAu, and (f) 40 nm BPEI-nAu, Figure S6: in situ nAu concentration (particles/mL) examined using Nanoparticle Tracking Analysis (NTA), Figure S7: TEM-EDX spectra confirming the absence of nAu internalization on plant roots: (a) control, (b) 5 nm cit-nAu, (c) 20 nm-cit nAu, (d) 40 nm cit-nAu, (e) 5 nm BPEI-nAu, (f) 20 nm BPEI-nAu, and (g) 40 nm BPEI.

Keywords

Aquatic higher plants, Salvinia minima Baker, Adsorption, Accumulation, Biomass, Gold engineered nanoparticles

Sustainable Development Goals

Citation

Mahaye, N.; Thwala, M.; Musee, N. Interactions of Coated-Gold Engineered Nanoparticles with Aquatic Higher Plant Salvinia minima Baker. Nanomaterials 2021, 11, 3178. https://DOI.org/ 10.3390/nano11123178.