Abstract
The coating of metallic nanoparticles with polymer is of interest to provide stability to the suspensions of said nanoparticles. On the other hand, there are thermosensitive polymers that respond according to the temperatures to which they are exposed.This study aimed to evaluate and characterize the system made up of gold nanoparticles and a version of the thermosensitive copolymer PNIPAAM-PAMPTMA (+) 48/6. For this, dynamic light scattering techniques, zeta potential and ultraviolet visible spectroscopy were used. PNIPAAM-PAMPTMA (+) 48/6 was subjected to tests at different temperatures in which it was confirmed that the lower critical dissolution temperature of the copolymer is approximately 35 oC and that in the presence of a saline medium it tends to add independently of the temperature. On the other hand, the copolymer was mixed with gold nanoparticles to study its behavior at ionic forces between 0 M and 0.75 M. It was found that, by varying the ionic strength in the mentioned range, the coating of the gold nanoparticles by part of the polymer is effective since no aggregation thereof was observed. This was corroborated by the UV-visible spectrum where, the spectra of the system (or nanocomposite) copolymer-nanoparticle at ionic strengths of 0 M and 0.75 M are practically equal to the spectrum when the gold nanoparticles have not added, that is to say , the plasmon peak appears in all cases at the same approximate wavelength of 530 nm. Finally, the evolution of the copolymer-nanoparticle system was studied at different temperatures and ionic forces of 0 M and 0.75 M. It was detected that both the influence of temperature and ionic strength cause the copolymer-nanoparticle system to increase its size. . However, the gold nanoparticles inside it remain without aggregating.
References
Dondapati, S. K., Sau, T. K., Hrelescu, C., Klar, T. A., Stefani, F. D., & Feldmann, J. (2010). Label-free Biosensing Based on Single Gold Nanostars as Plasmonic Transducers. ACS Nano, 4(11), 6318-6322. doi: https://doi.org/10.1021/nn100760f
Rastogi, L., Kora, A. J., & Arunachalam, J. (2012). Highly stable, protein capped gold nanoparticles as effective drug delivery vehicles for amino-glycosidic antibiotics. Materials Science and Engineering C, 32(6), 1571-1577. doi: https://doi.org/10.1016/j.msec.2012.04.044
Zhang, X. (2015). Gold Nanoparticles: Recent Advances in the Biomedical Applications. Cell Biochemistry and Biophysics, 72(3), 771-775. doi: https://doi.org/10.1007/s12013-015-0529-4
Pamies, Ramón, Cifre, J. G. H., Espín, V. F., Collado-González, M., Baños, F. G. D., & De La Torre, J. G. (2014). Aggregation behaviour of gold nanoparticles in saline aqueous media. Journal of Nanoparticle Research, 16(4). doi: https://doi.org/10.1007/s11051-014-2376-4
Pamies, Ramón, Zhu, K., Volden, S., Kj0niksen, A. L., Karlsson, G., Glomm, W. R., & Nyström, B. (2010a). Temperature induced flocculation of gold particles with an adsorbed thermoresponsive cationic copolymer. Journal of Physical Chemistry C, 114(50), 21960-21968. doi: https://doi.org/10.1021/jp106520k
Napper, D. H., & Netschey, A. (1971). Studies of the Steric Stabilization of Colloidal Particles. Journal of Colloid and Interface Science, 37(3), 528-535. doi: https://doi.org/10.1016/0021-9797(71)90330-4
Yavuz, M. S., Cheng, Y., Chen, J., Cobley, C. M., Zhang, Q., Rycenga, M., Xie, J., Kim, C., Song, K. H., Schwartz, A. G., Wang, L. V, & Xia, Y. (2009). Gold nanocages covered by smart polymers for controlled release with near-infrared light. Nature Materials, 8(12), 935-939. doi: https://doi.org/10.1038/nmat2564
Collado-González, M., Fernández Espín, V., Montalbán, M. G., Pamies, R., Hernández Cifre, J. G., Díaz Baños, F. G., Víllora, G., & García de la Torre, J. (2015). Aggregation behaviour of gold nanoparticles in presence of chitosan. Journal of Nanoparticle Research, 17(6). doi: https://doi.org/10.1007/s11051-015-3069-3
Fernandez Espin, V. (2017). Técnicas instrumentales y computacionales para la caracterización de sistemas de macromoléculas y nanopartículas. Implementación y aplicaciones [Tesis de Doctorado]. En Universidad de Murcia. doi: https://doi.org/10.13140/RG.2.1.2171.2482
Zhu, K., Jin, H., Kj0niksen, A. L., & Nyström, B. (2007). Anomalous transition in aqueous solutions of a thermoresponsive amphiphilic diblock copolymer. Journal of Physical Chemistry B, 111(37), 10862-10870. doi: https://doi.org/10.1021/jp074163m
Bayati, S., Zhu, K., Trinh, L. T. T., Kj0niksen, A. L., & Nyström, B. (2012). Effects of temperature and salt addition on the association behavior of charged amphiphilic diblock copolymers in aqueous solution. Journal of Physical Chemistry B, 116(36), 11386-11395. doi: https://doi.org/10.1021/jp306833x
Schild, H. G. (2003). Poly(N-isopropylacrylamide): experiment, theory and application. Progress in Polymer Science, 17(2), 163-249. doi: https://doi.org/10.1016/0079-6700(92)90023-r
Zhu, M. Q., Wang, L. Q., Exarhos, G. J., & Li, A. D. Q. (2004). Thermosensitive Gold Nanoparticles. Journal of the American Chemical Society, 126(9), 2656-2657. doi: https://doi.org/10.1021/ja038544z
Pecora, R. (1964). Doppler shifts in light scattering from pure liquids and polymer solutions. The Journal of Chemical Physics, 40(6), 1604-1614. doi: https://doi.org/10.1063/1.1725368
Pamies, R, Cifre, J. G. H., & De La Torre, J. G. (2007). Brownian dynamics simulation of polyelectrolyte dilute solutions under shear flow. Journal of Polymer Science, Part B: Polymer Physics, 45(1), 1-9. doi: https://doi.org/10.1002/polb.20994
Zeng, F., Tong, Z., & Sato, T. (1999). Molecular chain properties of poly (N-isopropyl acrylamide). Science in China, Series B: Chemistry, 42(3), 290-297. doi: https://doi.org/10.1007/BF02874245
Sztandera, K., & Gorzkiewicz Michatand Klajnert-Maculewicz, B. (2018). Gold Nanoparticles in Cancer Treatment. doi: https://doi.org/10.1021/acs.molpharmaceut.8b00810

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