Abstract
This paper describes a label free technique for determining ligand loading on metal nanoparticles using a variant of secondary ion mass spectrometry. Au 400 4+ clusters bombard DNA-functionalized anisotropic gold nanostars and isotropic nanospheres with similar surface areas to determine ligand density. For each projectile impact, co-localized molecules within the emission area of a single impact (diameter of 10-15 nm) were examined for each particle. Individual nanoparticle analysis allows for determination of the relationship between particle geometry and DNA loading. We found that branched particles exhibited increased ligand density versus nanospheres and determined that positive and neutral curvature could facilitate additional loading. This methodology can be applied to optimize loading for any ligand-core interaction independent of nanoparticle core, ligand, or attachment chemistry.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5566-5572 |
| Number of pages | 7 |
| Journal | Analytical Chemistry |
| Volume | 91 |
| Issue number | 9 |
| DOIs | |
| State | Published - May 7 2019 |
Funding
This work was supported by National Science Foundation (NSF) Grants CHE-1507790 (K.C. and T.W.O.), CHE-1808502 (E.E.C.), and CHE-1308312 (M.J.E. and E.A.S.) and the National Cancer Institute of the National Institutes of Health via Grant U54CA199091 (E.E.C. and T.W.O.). This work made use of the Northwestern University Keck Biophysics Facility supported by a Cancer Center Support Grant and the Biological Imaging Facility. Use of the Texas A&M University Materials Characterization Facility and the assistance of Dr. Bisrat are acknowledged. The authors are grateful for the use of EPIC of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF Grant NNCI-1542205), the MRSEC program (NSF Grant DMR-1121262) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois, through the IIN.
ASJC Scopus subject areas
- Analytical Chemistry