Organic coating of 1-2-nm-size silicon nanoparticles： Effect on particle properties

• Published in: Nano research 2015-06, Vol.8 (6), p.2047-2062
• Main Authors: Lillo, Cristian R., Romero, Juan J., Portolés, Manuel Llansola, Diez, Reinaldo Pis, Caregnato, Paula, Gonzalez, Mónica C.
• Format: Article
• Language: English
• Subjects: Anisotropy; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Cancer therapies; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Constants; Energy transfer; Folic acid; Fourier transforms; Ground state; Infrared spectroscopy; Light scattering; Materials Science; Nanoparticles; Nanostructure; Nanotechnology; Photoluminescence; Protein adsorption; Proteins; Radiation; Research Article; Silicon; Tumors; Vitamin B; X射线光电子能谱; 傅立叶变换红外光谱仪; 有机涂层; 硅纳米颗粒; 粒子特性; 蛋白质吸附; 超氧阴离子自由基; 透射电子显微镜
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-015-0716-z

Photoluminescent silicon nanoparticles 1-2 nm in size were synthesized by a wet chemical procedure and derivatized with propylamine （NH2SiNP）. Surface NH2 groups were used as linkers for additional poly（ethylene glycol） （PEG） and folic acid （Fo） attachment （PEG-NHSiNP and Fo-NHSiNP, respectively） to enable efficient targeting of the particles to tumors and inflammatory sites. The particles were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ζ potential, dynamic light scattering, and time-resolved anisotropy. The photophysical properties and photosensitizing capacity of the particles and their interaction with proteins was dependent on the nature of the attached molecules. While PEG attachment did not alter the photophysical behavior of NH2SiNP, the attachment of Fo diminished particle photoluminescence. Particles retained the capacity for 1O2 generation; however, efficient 1O2 quenching by the attached surface groups may be a drawback when using these particles as 1O2photosensitizers. In addition, Fo attachment provided particles with the capacity to generate the superoxide anion radical （O2-）. The particles were able to bind tryptophan residues of bovine serum albumin （BSA） within quenching distances. NH2SiNP and PEG-NHSLNP ground state complexes with BSA showed binding constants of （3.1 ± 0.3） × 10^4 and （1.3 ±0.4） × 10^3 M-1, respectively. The lower value observed for PEG-NHSiNP complexes indicates that surface PEGylation leads to a reduction in protein adsorption, which is required to prevent opsonization. An increase in particle luminescence upon BSA binding was attributed to the hydrophobic environment generated by the protein. NH2SiNP-BSA complexes were also capable of resonance energy transfer.