Highly controlled silica coating of PEG-capped metal nanoparticles and preparation of SERS-encoded particles.
Thiol-modified poly(ethylene glycol) (mPEG-SH) has been used to replace standard capping agents from the surfaces of gold nanoparticles with different sizes and shapes. Upon PEG stabilization, the nanoparticles can be transferred into ethanol, where silica can be directly grown on the particle surfaces through the standard Stober process. The obtained silica shells are uniform and homogeneous, and the method allows a high degree of control over shell thickness for any particle size and shape. Additionally, Raman-active molecules can be readily incorporated within the composite nanoparticles during silica growth so that SERS/SERRS-encoded nanoparticles can be fabricated containing a variety of tags, thereby envisaging multiplexing capability.
Fernández-López
Cristina
C
Departamento de Química Física and Unidad Asociada CSIC-Universidade de Vigo, 36310 Vigo, Spain.
Mateo-Mateo
Cintia
C
Alvarez-Puebla
Ramón A
RA
Pérez-Juste
Jorge
J
Pastoriza-Santos
Isabel
I
Liz-Marzán
Luis M
LM
D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D000431:Ethanol; D053768:Metal Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds
D020099:Coated Materials, Biocompatible; D013438:Sulfhydryl Compounds; D000431:Ethanol; D011092:Polyethylene Glycols; D012822:Silicon Dioxide