Novel method to label solid lipid nanoparticles with 64cu for positron emission tomography imaging

Area of Science:

• Nanotechnology
• Radiochemistry
• Biomedical Imaging

Background:

• Solid lipid nanoparticles (SLNs) are emerging colloidal carriers for intravenous drug delivery.
• Understanding in vivo biodistribution of SLNs is crucial for their therapeutic application.
• Positron emission tomography (PET) offers a non-invasive method for tracking nanoparticles, but requires radiolabeling.

Purpose of the Study:

• To develop and validate a method for radiolabeling SLNs with copper-64 for in vivo PET imaging.
• To quantitatively assess the biodistribution of radiolabeled SLNs in mice.
• To confirm the stability of the radiolabeling and the SLN structure in vivo.

Main Methods:

• Incorporation of a copper-specific chelator (BAT) into SLNs.
• Radiolabeling of SLNs with copper-64 (⁶⁴Cu).
• In vivo PET imaging and ex vivo gamma counting in mice.
• Stability assays to confirm radiolabel integrity.

Main Results:

• Successful radiolabeling of SLNs with ⁶⁴Cu achieved a yield of 66.5%, with >95% radiolabeled particles post-purification.
• PET imaging revealed SLNs circulating in the bloodstream with a half-life of approximately 1.4 hours.
• Quantitative analysis showed SLNs are largely cleared by 48 hours, with 5-7%ID/g remaining in the liver.

Conclusions:

• SLNs can be effectively radiolabeled with ⁶⁴Cu using the BAT chelator.
• In vivo PET imaging provides quantitative biodistribution data for SLNs.
• This radiolabeling method enables further investigation of SLN behavior for drug delivery applications.