Programmed Nanoparticle-Loaded Nanoparticles for Deep-Penetrating 3D Cancer Therapy

Tumors are 3D, composed of cellular agglomerations and blood vessels. Therapies involving nanoparticles utilize specific accumulations due to the leaky vascular structures. However, systemically injected nanoparticles are mostly uptaken by cells located on the surfaces of cancer tissues, lacking deep penetration into the core cancer regions. Herein, an unprecedented strategy, described as injecting nanoparticle-loaded nanoparticles to address the long-lasting problem is reported for effective surface-to-core drug delivery in entire 3D tumors. The nanoparticle-loaded nanoparticle is a silica nanoparticle (approximate to 150 nm) with well-developed, interconnected channels (diameter of approximate to 30 nm), in which small gold nanoparticles (AuNPs) (approximate to 15 nm) with programmable DNA are located. The nanoparticle (AuNPs)-loaded nanoparticles (silica): (1) can accumulate in tumors through leaky vascular structures by protecting the inner therapeutic AuNPs during blood circulation, and then (2) allow diffusion of the AuNPs for penetration into the entire surface-to-core tumor tissues, and finally (3) release a drug triggered by cancer-characteristic pH gradients. The hierarchical nanoparticle-loaded nanoparticle can be a rational design for cancer therapies because the outer large nanoparticles are effective in blood circulation and in protection of the therapeutic nanoparticles inside, allowing the loaded small nanoparticles to penetrate deeply into 3D tumors with anticancer drugs.