X-ray enabled detection and eradication of circulating tumor cells with nanoparticles

The early detection and eradication of circulating tumor cells (CTCs) play an important role in cancer metastasis management. This paper describes a new nanoparticle-enabled technique for integrated enrichment, detection and killing of CTCs by using magnetic nanoparticles and bismuth nanoparticles, X-ray fluorescence spectrometry, and X-ray radiation. The nanoparticles are modified with tumor targeting agents and conjugated with tumor cells through folate receptors over-expressed on cancer cells. A permanent micro-magnet is used to collect CTCs suspended inside a flowing medium that contains phosphate buffered saline (PBS) or whole blood. The characteristic X-ray emissions from collected bismuth nanoparticles, upon excitation with collimated X-rays, are used to detect CTCs. Results show that the method is capable of selectively detecting CTCs at concentrations ranging from 100–100,000 cells/mL in the buffer solution, with a detection limit of ∼100 CTCs/mL. Moreover, the dose of primary X-rays can be enhanced to kill the localized CTCs by radiation induced DNA damage, with minimal invasiveness, thus making in vivo personalized CTC management possible.

► Simultaneous enrichment, detection and killing of CTCs have been achieved.
► Nanoparticles are modified to target receptors overexpressed on CTCs.
► X-ray fluorescence signals from nanoparticles are used to detect CTCs.
► CTC detection ranges from 102 to 105 cells/mL in buffer.
► X-ray dose can be enhanced to kill >80% of the localized CTCs.