8 - Nanoparticles for tumor targeting

Abstract

Nanotechnology is regarded as one of the most promising tools to surpass traditional chemotherapy as a front-line tumor treatment. Nanosized (below 1000nm) drug carriers possessing the advantages of biodegradability, biocompatibility, nontoxicity, and prolonged circulation offer a versatile platform to which many useful functionalities can be added to improve the specificity and effectiveness of tumor treatment. Nanoparticles come in a large variety of forms (dendrimer nanoparticles, liposomes, polymer nanoparticles, polymersomes, hybrid nanoparticles, inorganic nanoparticles, solid lipid nanoparticles, biomimetic nanoparticles, etc.) and a broad range of sizes (from a few nanometers to 1000nm). The outstanding features are their distinctive size, shape, and surface properties for tissue penetration via a passive and active targeting way. Nanoparticles achieve passive tumor accumulation because of the leaky and disorganized nature of the blood vessels and the dysfunctional lymph vessels in solid tumor. Modified with targeting moieties, such as antibodies, antibody fragments, specific molecules, small peptides, RNA aptamers, etc., the nanoparticles can target specific receptors and antigens expressed exclusively or overexpressed on the tumor cell surface or the tumor microenvironment, reducing side effects on normal tissue. Smart nanoparticles in response to physical, chemical, or biological triggers can lead to controlled release of therapeutics into tumor tissues and cells, with concomitant advantages of boosted delivery efficiency and therapeutic efficacy. By modulating the tumor microenvironment to disrupt some barriers for nanoparticle delivery, enhanced tumor nanoparticle delivery can also be achieved. Finally, we provide perspectives on the design and translation of nanoparticles for tumor targeting.