Engineering CRISPR nanoplatforms to deplete cancer stem cells: Delivery checkpoints, target plasticity, and clinical viability.

Cancer stem cells (CSCs) sustain tumor initiation, therapy resistance, and relapse, yet evade durable control because they switch phenotype, enter quiescence, shelter within protective niches, resist drug efflux, and share markers with normal stem cells. Programmable CRISPR editing can disable intracellular self-renewal dependencies that antibodies and small molecules cannot reach, whereas only nanoscale carriers can confine such editing to intended cells; neither component alone solves the CSC problem. This review reframes CSC-directed CRISPR nanomedicine as an integrated design problem. We examine why target plasticity defeats static single-marker targeting; the sequential delivery checkpoints spanning blood stability, organ selection, tumor penetration, CSC recognition, endosomal escape, and productive editing; and advanced architectures including organ-selective lipid nanoparticles, biomimetic and vesicle carriers, metal-organic frameworks, and logic-gated systems. Genotoxicity, immunogenicity, incomplete depletion, manufacturing reproducibility, and absent CSC-specific clinical evidence remain limiting. Clinical viability, not imminent cure, is the realistic near-term objective.