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DNA-functionalized gold nanoparticles in macromolecularly crowded polymer solutions
Jeehae Shin1, Xu Zhang, Juewen Liu
1Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
The Journal of Physical Chemistry. B
|November 2, 2012
Summary
DNA-functionalized gold nanoparticles (AuNPs) aggregate in polyethylene glycol (PEG) solutions, unlike in buffer. This aggregation is driven by depletion forces, not DNA base pairing, impacting nanobiotechnology applications.
Area of Science:
- Nanobiotechnology
- Nanoscience
- Analytical Chemistry
Background:
- DNA-functionalized gold nanoparticles (AuNPs) are key in nanobiotechnology.
- Cellular crowding affects nanoparticle behavior, potentially inducing aggregation.
- Polyethylene glycol (PEG) is used to model crowded cellular environments.
Purpose of the Study:
- Investigate the stability of DNA-functionalized AuNPs in PEG solutions.
- Understand the aggregation mechanism of DNA-AuNPs in crowded environments.
- Explore the influence of PEG properties and temperature on AuNP aggregation.
Main Methods:
- Studied DNA-functionalized AuNPs in buffer and PEG solutions.
- Varied PEG molecular weight, concentration, and temperature.
- Observed AuNP aggregation and analyzed melting transitions.
Main Results:
- DNA-AuNPs are unstable and aggregate in PEG, contrasting with stability in buffer.
- Citrate-capped AuNPs remain stable in PEG.
- Aggregation in PEG is mediated by depletion forces, not DNA base pairing, showing broad melting.
- PEG concentration, molecular weight, and temperature influence aggregation.
- Observed PEG phase separation and AuNP partitioning at high temperatures.
Conclusions:
- DNA-functionalized AuNPs aggregate in PEG due to depletion forces, a critical factor for nanobiotechnology applications in biological mimics.
- The aggregation mechanism differs from typical DNA-mediated transitions, highlighting the role of excluded volume effects.
- Environmental factors like PEG properties and temperature significantly alter AuNP behavior and stability.
