Recent Advances in Nanofabrication Strategies for Biosensors: From Precision Nanopatterning to Scalable, Flexible, and AI-Assisted Manufacturing.

Nanofabrication has become central to the development of high-performance biosensors by enabling precise control over sensing interfaces, enhanced signal transduction, and integration across optical, electrochemical, microfluidic, and wearable platforms. This review examines the evolution of biosensor nanofabrication from deterministic top-down patterning toward scalable and integrated manufacturing strategies. Top-down approaches, including electron-beam lithography, focused ion beam milling, nanoimprint lithography, reactive ion etching, and laser-based fabrication, are discussed alongside replication and transfer processes, soft lithography, lithography-free plasmonic structuring, and additive three-dimensional fabrication. Bottom-up strategies based on nanoparticle assembly, DNA nanotechnology, block-copolymer and nanoporous templating, and stimuli-responsive materials are further considered as routes to programmable nanoscale organization and functional biointerfaces. Particular attention is given to flexible and wearable biosensors, where substrate mechanics, conductive-interface fabrication, textile integration, epidermal microfluidics, packaging, power management, and wireless communication introduce manufacturing requirements beyond conventional rigid devices. Across these approaches, the review emphasizes that analytical sensitivity alone is insufficient for translation; nanoscale precision must be accompanied by reproducibility, scalable processing, stable biofunctionalization, antifouling performance, packaging, storage stability, and device-level quality control. Emerging AI-assisted fabrication and process optimization strategies are also discussed as tools for linking manufacturing parameters with structural and analytical performance. Overall, the review provides a manufacturing-oriented perspective on how hybrid nanofabrication strategies can bridge high-performance laboratory biosensors with reproducible, scalable, and application-ready sensing systems.