Bifunctionalized Silver Nanoparticles as Hg2+ Plasmonic Sensor in Water: Synthesis, Characterizations, and Ecosafety

Paolo Prosposito; Luca Burratti; Arianna Bellingeri; Giuseppe Protano; Claudia Faleri; Ilaria Corsi; Chiara Battocchio; Giovanna Iucci; Luca Tortora; Valeria Secchi; Stefano Franchi; Iole Venditti

doi:10.3390/nano9101353

Bifunctionalized Silver Nanoparticles as Hg²⁺ Plasmonic Sensor in Water: Synthesis, Characterizations, and Ecosafety

Nanomaterials (Basel). 2019 Sep 20;9(10):1353. doi: 10.3390/nano9101353.

Authors

Paolo Prosposito^{1

2}, Luca Burratti³, Arianna Bellingeri⁴, Giuseppe Protano⁵, Claudia Faleri⁶, Ilaria Corsi⁷, Chiara Battocchio⁸, Giovanna Iucci⁹, Luca Tortora^{10

11}, Valeria Secchi¹², Stefano Franchi¹³, Iole Venditti¹⁴

Affiliations

¹ Department of Industrial Engineering and INSTM, University of Rome Tor Vergata, via del Politecnico 1, 00133 Rome, Italy. paolo.prosposito@uniroma2.it.
² Center for Regenerative Medicine, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy. paolo.prosposito@uniroma2.it.
³ Department of Industrial Engineering and INSTM, University of Rome Tor Vergata, via del Politecnico 1, 00133 Rome, Italy. luca.burratti@uniroma2.it.
⁴ Department of Physical, Earth and Environmental Sciences, University of Siena, Via Mattioli 4, 53100 Siena, Italy. arianna.bellingeri@student.unisi.it.
⁵ Department of Physical, Earth and Environmental Sciences, University of Siena, Via Mattioli 4, 53100 Siena, Italy. giuseppe.protano@unisi.it.
⁶ Department of Life Sciences, via Mattioli 4, 53100 Siena, Italy. faleric@unisi.it.
⁷ Department of Physical, Earth and Environmental Sciences, University of Siena, Via Mattioli 4, 53100 Siena, Italy. ilaria.corsi@unisi.it.
⁸ Department of Sciences, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy. chiara.battocchio@uniroma3.it.
⁹ Department of Sciences, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy. giovanna.iucci@uniroma3.it.
¹⁰ Department of Sciences, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy. luca.tortora@uniroma3.it.
¹¹ Surface Analysis Laboratory INFN Roma Tre, via della Vasca Navale 84, 00146 Rome, Italy. luca.tortora@uniroma3.it.
¹² Department of Sciences, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy. valeria.secchi@uniroma3.it.
¹³ Elettra-Sincrotrone Trieste S.c.p.A., Strada Statale 14, km 163.5, 34149 Basovizza Trieste, Italy. stefano.franchi@elettra.eu.
¹⁴ Department of Sciences, Roma Tre University of Rome, Via della Vasca Navale 79, 00146 Rome, Italy. iole.venditti@uniroma3.it.

Abstract

In this work, hydrophilic silver nanoparticles (AgNPs), bifunctionalized with citrate (Cit) and L-cysteine (L-cys), were synthesized. The typical local surface plasmon resonance (LSPR) at λ _max = 400 nm together with Dynamic Light Scattering (DLS) measurements (<2R_H> = 8 ± 1 nm) and TEM studies (Ø = 5 ± 2 nm) confirmed the system nanodimension and the stability in water. Molecular and electronic structures of AgNPs were investigated by FTIR, SR-XPS, and NEXAFS techniques. We tested the system as plasmonic sensor in water with 16 different metal ions, finding sensitivity to Hg²⁺ in the range 1-10 ppm. After this first screening, the molecular and electronic structure of the AgNPs-Hg²⁺ conjugated system was deeply investigated by SR-XPS. Moreover, in view of AgNPs application as sensors in real water systems, environmental safety assessment (ecosafety) was performed by using standardized ecotoxicity bioassay as algal growth inhibition tests (OECD 201, ISO 10253:2006), coupled with determination of Ag⁺ release from the nanoparticles in fresh and marine aqueous exposure media, by means of ICP-MS. These latest studies confirmed low toxicity and low Ag⁺ release. Therefore, these ecosafe AgNPs demonstrate a great potential in selective detection of environmental Hg²⁺, which may attract a great interest for several biological research fields.

Keywords: Hg2+ sensors; ecosafety; heavy metal sensing; optical sensors; plasmonic sensors; silver nanoparticles.