From small to large-The application of in situ polymerization within tumor cells

The“laboratory”of cells has the capacity to polymerize monosaccharides,amino acids,and nucleotides.Tumor cells,characterized by the overexpression of multi-ple enzymes and existing in a slightly acidic and highly redox-potent environment,have attracted the attention of chemists aiming to transfer chemical reactions from the traditional laboratoryflask to this“cellular laboratory”.Polymers,resulting from the repetitive linkage of monomers,have garnered extensive utility in the biomed-icalfield due to their diverse structural and physicochemical properties.When the polymerization reaction proceeds in situ within the tumor cells,this in situ trans-formation from small-to-large combines the rapid uptake of monomeric molecules with the strong retention ability of polymers,exerting a profound impact on drug delivery within tumors.Moreover,it shows promising applications in the regulation of cell behavior,imaging,therapy,and theranostics.Given the diverse functions of in situ polymerization in relation to tumor cells,this review focuses on a comprehen-sive examination of various strategies for in situ polymerization within tumor cells,categorizing these strategies based on the formation mechanisms of polymers.The applications in this domain concerning in situ polymerization within tumor cells are also explored.Moreover,a discussion of specific limitations in current research and insights into potential future directions from the authors’perspective are provided.