Intracellular localization of nanoparticle dimers by chirality reversal

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Spectroscopy

Background:

• Plasmonic nanoparticle (NP) localization (intracellular vs. extracellular) critically impacts therapeutic and diagnostic outcomes.
• Current spectroscopic methods fail to differentiate NP location during transmembrane transport.
• Distinguishing NP location is essential for effective nanomedicine and understanding cellular interactions.

Purpose of the Study:

• To develop a real-time spectroscopic method for tracking plasmonic nanoparticle internalization into mammalian cells.
• To differentiate between extracellular and intracellular localization of DNA-bridged NP dimers.
• To demonstrate the application of this technique in targeted photodynamic cancer therapy.

Main Methods:

• Utilizing the chiroptical activity of DNA-bridged plasmonic nanoparticle dimers.
• Employing real-time ensemble spectroscopy to monitor changes in circular dichroism during cellular uptake.
• Investigating the correlation between NP twisting motion, electrostatic repulsion changes, and transmembrane transport.

Main Results:

• Chiroptical activity, specifically circular dichroism peaks, changes sign (negative to positive) during NP internalization.
• A spontaneous twisting motion around the DNA bridge, driven by altered electrostatic repulsion, accompanies transmembrane transport.
• The study demonstrated enhanced cervical cancer cell elimination using photodynamic therapy when photon polarization matched intracellular NP dimer absorption.

Conclusions:

• Chiroptical activity of DNA-bridged NP dimers provides a novel spectroscopic tool for real-time monitoring of nanoparticle cellular internalization.
• This method allows for accurate differentiation of intracellular versus extracellular NP localization.
• Spectroscopic targeting of chiral nanostructures shows significant potential for improving the efficacy of nanomedicine, particularly in photodynamic therapy for cancer treatment.