Translational bioengineering perspectives on biosensors and nanorobotics for cancer theranostics

The convergence of diagnostics and therapeutics, known as cancer theranostics, has become the backbone of 21st-century precision oncology. In the past decade, exponential progress in the engineering of nano-biosensors, nanorobotic actuation, and molecular biomarker profiling has allowed for the interrogation of tumors in real-time and at the site with sensitivities not possible with conventional clinical modalities. This systematic analytical review discusses the mechanistic principles, translational development, and clinical development of biosensor-nanorobotic theranostic architectures. In addition to DNA origami nanorobots, magnetically actuated microswimmers, bacteria-propelled siRNA carriers, and ultrasound-controlled nanomotors, electrochemical aptasensors with a LOD of 0.01 pg/mL for prostate-specific antigen, graphene field-effect transistors with a LOD of 10 fM for HER2, and CRISPR-Cas12a biosensors with a LOD of 10 aM for KRAS mutation detection are critically reviewed. The integration of these into closed-loop theranostic systems, such as quantum dot-liposome assemblies, upconversion nanoparticle hybrids, and exosome-derived platforms, for simultaneous multiplexed imaging and adaptive therapy is discussed. The clinical translation barriers such as manufacturing scalability, regulatory pathways, and long-term biocompatibility are critically assessed. Prospective directions include AI-assisted navigation of nanorobots, organoid-based personalized theranostic, and integration with immunotheranostic. This review is a complete translation reference for researchers, clinicians, and biomedical engineers developing next-generation intelligent cancer management systems.