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Uptake of New Lipid-coated Nanoparticles Containing Falcarindiol by Human Mesenchymal Stem Cells
Published on: February 9, 2019
Folate-mediated tumor cell uptake of quantum dots entrapped in lipid nanoparticles
J E Schroeder1, I Shweky, H Shmeeda
1Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
Quantum dots (QDs) are fluorescent semiconductor nanocrystals with superior optical properties compared to organic dyes currently undergoing rapid development for biological applications, particularly in fluorescence imaging. The folate receptor, overexpressed in a broad spectrum of malignant tumors, is an attractive target for selective delivery of imaging agents to tumor cells. This study examines nanoparticles containing QDs entrapped in a lipid shell, and post-loaded with a folate-lipid conjugate for targeting to mouse and human tumor cells expressing the folate receptor. Hydrophobic QDs were mixed with 1,2 dipalmitoyl-sn-glycero-3 phosphocholine and methoxy-polyethylene-glycol-distearoyl-phosphatidyl-ethanolamine (mPEG-DSPE) generating a nanoparticle referred to as lipodot, with a mean diameter size of approximately 100 nm. Folate-derivatized PEG-DSPE was post-loaded into the lipodots at 0.5% lipid molar concentration. Mouse J6456 lymphoma cells (J6456-FR) and human head and neck KB cancer cells (KB-FR), up-regulated for their folate receptors, were incubated with folate-targeted and non-targeted lipodots in vitro. Using fluorescence microscopy, it was found that only folate-targeted lipodots were taken up by tumor cells. Confocal depth scanning showed substantial internalization. Confirming the specificity of folate-targeted lipodots, binding and internalization were inhibited by free folate, and no uptake was found in a folate-receptor negative cell line. Selective binding and uptake of folate-targeted lipodots by J6456-FR cells was also observed in vivo after intra-peritoneal injection in mice bearing ascitic J6456-FR tumors based on FACS analysis and confocal imaging of harvested cells from the peritoneal cavity. Folate-targeted lipodots represent an attractive approach for tumor cell labeling both in vitro and in vivo.
Insights
Folate-targeted lipodots, nanoparticles with quantum dots (QDs), selectively bind and are internalized by folate receptor-expressing tumor cells both in vitro and in vivo, showing promise for cancer imaging.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Oncology
Background:
- Quantum dots (QDs) offer superior fluorescence imaging properties compared to organic dyes.
- The folate receptor is overexpressed in many malignant tumors, making it a target for selective cancer therapies.
- Targeted delivery systems are crucial for enhancing the efficacy of diagnostic and therapeutic agents in oncology.
Purpose of the Study:
- To develop and evaluate folate-targeted lipodots for selective labeling of tumor cells.
- To investigate the in vitro and in vivo targeting efficiency of these nanoparticles.
- To assess the potential of folate-targeted lipodots in cancer imaging applications.
Main Methods:
- Quantum dots were encapsulated within lipid shells to form lipodots (approx. 100 nm diameter).
- Folate-derivatized lipids were post-loaded onto lipodots for targeted delivery.
- In vitro studies used folate receptor-positive (J6456-FR, KB-FR) and negative cell lines.
- In vivo studies involved injecting targeted lipodots into mice with J6456-FR tumors.
Main Results:
- Folate-targeted lipodots demonstrated selective uptake by folate receptor-expressing tumor cells in vitro.
- Internalization was confirmed via fluorescence microscopy and confocal scanning.
- Specificity was validated by inhibition with free folate and lack of uptake in receptor-negative cells.
- Selective binding and uptake were observed in vivo in mice bearing folate receptor-positive tumors.
Conclusions:
- Folate-targeted lipodots effectively target tumor cells expressing folate receptors.
- These nanoparticles show significant potential for in vitro and in vivo tumor cell labeling.
- Lipodot technology offers a promising platform for advancing cancer imaging and diagnostics.
