Polyacrylic Acid-Coated LaB₆ Nanoparticles as Efficient Sensitizers for Binary Proton Therapy

Area of Science:

• Nanotechnology
• Radiation Oncology
• Materials Science

Background:

• Proton beam therapy (PBT) offers precise tumor targeting via the Bragg peak, but its clinical use is limited by economic and radiobiological factors.
• Enhancing the relative biological effectiveness (RBE) of PBT is crucial for broader adoption.
• Radiosensitizers are being explored to improve PBT efficacy.

Purpose of the Study:

• To investigate lanthanum hexaboride (LaB₆) nanoparticles coated with polyacrylic acid (PAA) as radiosensitizers for PBT.
• To evaluate the safety and efficacy of LaB₆-PAA nanoparticles in combination with proton irradiation.

Main Methods:

• LaB₆ nanoparticles were synthesized and functionalized with PAA.
• In vitro and in vivo studies assessed NP safety and antitumor efficacy in combination with PBT.
• Biodistribution of LaB₆-PAA NPs was evaluated in animal models.

Main Results:

• LaB₆-PAA nanoparticles significantly enhanced cancer cell death in vitro when combined with PBT.
• In vivo studies showed that PBT with LaB₆-PAA NPs was well tolerated, despite lower-than-expected antitumor efficacy in sensitive xenografts.
• The combination therapy demonstrated good tolerability in preclinical models.

Conclusions:

• LaB₆-PAA nanoparticles show potential as effective radiosensitizers for proton beam therapy.
• This approach may improve therapeutic outcomes in PBT by enhancing biological effectiveness.
• Further research is warranted to optimize this promising combination therapy.