Experiencias previas con el emprendimiento y actividades empresariales:

ASYMMETRIC FLOW FIELD FLOW FRACTIONATION HYPHENATED TO ICP-MS FOR GOLD NANOPARTICLES AND DISSOLVED GOLD SPECIES DETERMINATOIN IN CELL

CULTURE MEDIUM

S. López-Sanz1_{, N. Rodríguez Fariñas}1_{, R. C. Rodríguez Martín-Doimeadios}1_,

A. Ríos Castro2

1_{Department of Analytical Chemistry and Food Technology, Faculty of Environmental Sciences} and Biochemistry, University of Castilla-La Mancha, Avda. Carlos III s/n, 45071, Toledo, Spain. 2_{Department of Analytical Chemistry and Food Technology, Faculty of Chemical Sciences and}

Technologies, University of Castilla-La Mancha, Avda. Camilo José Cela s/n, 13071, Ciudad Real, Spain.

e-mail: [email protected]

The use of nanoparticles (NPs) in different fields has rapidly grown in the last decades. Among them, gold nanoparticles (AuNPs) are widely used for biomedical applications. However, their impacts on the human health and the environment are not fully known. The study of the AuNPs toxicity addresses these concerns, but special attention should be paid to the AuNPs interaction with the matrix components and to the possibility of gold ion (Au3+_{) release. Therefore,} the characterization of NPs in complex matrices is necessary. For this purpose, the coupling of hydrodynamic separation techniques with specific detectors begin to play a decisive role [1]. Asymmetric flow field flow fractionation (AF4) is a recently proposed separation technique with a high potential in the field of NPs analysis. The separation takes place at low-to-medium pressure in an open channel without a stationary phase, so interactions between the NPs and stationary phase or mechanical stress are avoided, which in turn minimizes the generation of artefacts. The combination of AF4 and inductively coupled plasma mass spectrometry (ICP-MS) is an especially promising and interesting option, because of its particle size related power, its versatility, and its elemental specificity. However, its use for the characterization or detection of NPs in complex samples is still scarce.

Therefore, in the present work an analytical strategy based on AF4-ICP-MS has been developed to study AuNPs transformation in cell culture medium used in toxicity tests. Special attention was paid to the optimization of the separation conditions in the AF4. The dimensions of the channel and the characteristics of the membrane play an important role. Based on previous studies a 350 µm thick spacer and a regenerated cellulose membrane (MWCO of 10 kDa) were selected. Moreover, the composition of the carrier is decisive for the NPs stability and the interactions with the membrane. The presence of surfactants (0, 0.01 and 0.05 % sodium dodecyl sulphate (SDS)), phosphate buffer (without and with phosphate buffer 1 mM at pH 7.9), organic solvents (0, 2 and 4 % methanol) and different pH values (6 and 8) were studied. The optimum carrier composition was 0.01 % SDS at pH=6. The cross flow and the gradient time were also studied.

Under the final optimized separation conditions, dissolved Au3+ _{and AuNPs of 10 and 30} nm can be separated by AF4-ICP-MS, with a retention times of 8 min, 12.5 min and 18 min, respectively. An increase in the hydrodynamic volume of AuNPs and dissolved Au3+ _was observed in the presence of the cell culture medium, suggesting that AuNPs and Au3+ _{could be} coated by species such as proteins present in the culture medium. Oxidation of the AuNPs was also observed. The method will be used for the analysis of cells and supernatants obtained from toxicity test with cell culture under different experimental conditions.

References:

[1] S. López-Sanz, N. Rodríguez Fariñas, R. Serrano Vargas, R. C. Rodríguez Martín-Doimeadios, A. Ríos, Talanta 164 (2017) 451-457.

Acknowledgments:

PO-NT-07

4-FOLD PHOTOLUMINESCECE ENHANCEMENT IN CsPBr3 NANOCRYSTALS BY SPECIFIC BINDING AND ENCAPSULATION WITH AMINO-FUNCTIONALIZED SILANES

V. González-Pedro, A. Maquieira

1_{IDM, Instituto Interuniversitario de reconocimiento Molecular y Desarrollo Tecnológico,} Departamento de Química, Universitat Politècnica de València/UV, Valencia.

e-mail: [email protected]

Metal halide perovskites (PS) exhibit many appealing features such as high photoluminescence quantum yields, particle size of 5-15 nm, tunable emission properties and giant multiphoton absorption, which may enable fresh approaches for next generation of bioimaging and biosensing applications [1]. Nonetheless, their implementation stumbles with their poor chemical and structural stability in water and limited processability.

In the present work, we describe a facile methodology to prepare cubic green-emitting CsPbBr3 nanocrystals (NCs) encapsulated in an alcoxysilane shell. TEM microscopy and 1_{H-NMR studies} enabled to identify the presence of alkoxysilane surrounding the perovsite and elucidate the chemical bonding mechanisms of 3-aminopropyltriethoxysilane on NCs surface. However, the most relevant result of the investigation is the systematic increase in the emission properties observed for the CsPbX3 NCs treated with alkoxysilane. After the optimization of the methodology, nanocomposite particles exhibit an improvement in photoluminescence close to 400%, compared to uncoated counterparts. This result is of great importance, since it reveals the singular "defect chemistry" of perovskites, where most of the electron recombination phenomena occur on the surface of the nanocrystal, being practically negligible inside the nanoparticle. Therefore, our study reveals the fundamental role of interfacial properties and surface chemistry in modulating the optical properties of CsPbBr3 nanocrystals. [2]. On the other hand, the silica coating further increases the perovskite’s moisture resistance, thus rendering the PS NCs more stable in protic solvents compared to uncoated NCs.

Acknowledgements

This work was financially supported by FEDER projects BiHolog-CTQ2016-75749-R from MINECO and GVA PROMETEO II 2014/40. V.G-P. thanks Universitat Politècnica de València for her post-doctoral fellowship (Grant-PAID-10-14).

PO-NT-08

NANOCLUSTERS DE ORO COMO SONDAS DE OXÍGENO: DESACTIVACIÓN DE LA