Multistage nanoparticle delivery system for deep penetration into tumor tissue

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cancer Therapeutics

Background:

• Current FDA-approved cancer nanotherapeutics rely on the enhanced permeation and retention (EPR) effect for passive tumor accumulation.
• Nanotherapeutics of ≈100 nm often fail to penetrate dense tumor matrices due to physiological barriers, limiting their efficacy.
• Modest survival benefits from existing nanotherapeutics highlight the need for improved tumor penetration.

Purpose of the Study:

• To develop a multistage nanotherapeutic system capable of size reduction within the tumor microenvironment.
• To overcome the limitations of large nanoparticle size hindering intratumoral diffusion.
• To enhance the delivery and penetration of nanotherapeutics into dense tumor collagen matrices.

Main Methods:

• A multistage system was designed where 100-nm nanoparticles degrade to 10-nm nanoparticles upon exposure to tumor-specific proteases (e.g., MMP-2).
• Gelatin nanoparticles encapsulating quantum dots (QDs) were used as a model system to track size changes and diffusion.
• In vitro studies assessed MMP-2 activation and enhanced diffusive transport, while in vivo studies measured circulation half-life and intratumoral diffusion.

Main Results:

• In vitro studies demonstrated efficient and effective size reduction of nanoparticles triggered by MMP-2.
• The shrunken 10-nm nanoparticles exhibited enhanced diffusive transport within the tumor microenvironment.
• In vivo measurements confirmed a long circulation half-life for EPR effect and deep tumor penetration into dense collagen matrices.

Conclusions:

• The proposed multistage nanotherapeutic system effectively shrinks in response to the tumor microenvironment, improving intratumoral diffusion.
• This approach overcomes size-related barriers, enabling deeper penetration into dense tumor tissues.
• The system holds promise for enhancing the efficacy of cancer nanotherapeutics by improving drug delivery throughout the tumor.