Nanoparticles enter cell nuclei and report back via spectroscopy

Hitching a ride on an HIV protein known for its ability to penetrate human cells, silver nanoparticles have proven able to enter cell nuclei and report on their surroundings using light signals via surface-enhanced Raman scattering (SERS). Bioengineers at Duke University (Durham, NC) who devised the scheme hope to use it to recognize the very moment when genetic material within a cell begins to turn abnormal, triggering disorders such as cancer. They also envision using the technique to deliver drugs or other payloads directly into the nucleus.

SERS map showing intracellular distribution of 4-MBA-labeled silver nanoparticles in J774 cells after co-incubation for two hours.

The ability to place reflective particles into a cell's nucleus and gather information using light has potential implications for the selective treatment of disease. Nano silver is not rejected by cells, and is an efficient light reflector. In pairing it with the delivery vehicle, the researchers harnessed only the ability of HIV to sneak past cellular defenses, while stripping away its ability to take over the cell's genetic machinery. When the target molecule is coupled with a metal nanoparticle, the Raman response is greatly enhanced by the SERS effect-often by more than a million times.

Getting the nanoparticle into the nucleus enables many options-such as observing the effects of a payload on the nucleus, or enhancing the effectiveness of a drug treatment.

The Duke researchers reported their findings in a series of papers, culminating in the latest issue of Nanomedicine.¹

The current experiments were conducted with living cells in a laboratory; new experiments are focusing on using this approach in animal models to determine how it works in a complex living system.

1. M.K. Gregas et al., Nanomedicine (2010), doi: 10.1016/ j.nano.2010.07.009

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