Functional nucleic acids for cancer theranostics

Cancer is one of the leading causes of mortality worldwide, and worse still, the number of cancer cases is startlingly growing every year. The intrinsic complexity of tumors, including intratumor heterogeneity, dynamic evolution, and abnormal tumor microenvironments (TME), often leads to the failure of traditional chemotherapy. Cancer theranostics integrate molecular diagnosis and targeted cancer therapy, promoting the transition from conventional to personalized and precision medicine. Functional nucleic acids (FNAs), such as aptamers, DNAzymes, and DNA-based nanomachines (DNMs), are nucleic acids with functions beyond the well-known genetic roles. In addition to the basic advantages of nucleic acids-based materials, such as low cost, biocompatibility, low immunogenicity, and simplicity of chemical modification. FNAs also possess many superior properties, including high binding affinity and specificity of aptamers, efficient and specific gene editing ability of DNAzymes, and logic-controlled designability of DNA machines, all making FNAs an attractive material for applications in cancer theranostics in recent years. This review highlights the development and most recent applications of FNAs in cancer theranostics, as well as the challenges and opportunities in this research field.