Abstract
To better understand environmental behaviors of nanoparticles (NPs), we used the atomic force microscopy (AFM) to measure interaction forces between E. coli cells and NPs immobilized on surfaces in an aqueous environment. The results showed that adhesion force strength was significantly influenced by particle size for both hematite (α-Fe2O3) and corundum (α-Al2O3) NPs whereas the effect on the repulsive force was not observed. The adhesion force decreased from 6.3±0.7nN to 0.8±0.4nN as hematite NPs increased from 26nm to 98nm in diameter. Corundum NPs exhibited a similar dependence of adhesion force on particle size. The Johnson-Kendall-Roberts (JKR) model was employed to estimate the contact area between E. coli cells and NPs, and based on the JKR model a new model that considers local effective contact area was developed. The prediction of the new model matched the size dependence of adhesion force in experimental results. Size effects on adhesion forces may originate from the difference in local effective contact areas as supported by our model. These findings provide fundamental information for interpreting the environmental behaviors and biological interactions of NPs, which barely have been addressed.
Original language | English |
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Pages (from-to) | 316-324 |
Number of pages | 9 |
Journal | Colloids and Surfaces B: Biointerfaces |
Volume | 82 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1 2011 |
Externally published | Yes |
Funding
This study was partially supported by the U.S. Environmental Protection Agency Science to Achieve Results Program grant RD-83385601 and Semiconductor Research Corporation (SRC)/ESH grant ( 425.025 ).
Funders | Funder number |
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ESH | 425.025 |
Semiconductor Research Corporation | |
U.S. Environmental Protection Agency | RD-83385601 |
Keywords
- AFM
- Adhesion force
- Interfacial interactions
- Nanoparticle
- Size effect