Acoustic Microbots: Linking Fabrication Techniques to Acoustic Actuation Mechanisms—A Systematic Review

Abstract

Acoustic fields are emerging as a promising wireless and tissue‐penetrant power source for micro‐ and nanorobots, with propulsion efficiency, steering precision, and biocompatibility all critically linked to fabrication strategy. To clarify these interdependencies, we conducted a Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA)‐guided systematic review of literature from Scopus, Web of Science, PubMed, and IEEE Xplore (January 1, 2010–May 31 2025). Of 144 records, 63 primary studies and 22 secondary/background sources met predefined criteria and were synthesized. The evidence reveals five dominant actuation modes: boundary‐driven streaming (~40%), bubble oscillation (~25%), acoustic radiation forces (~12%), whole‐body resonance (~13%), and hybrid magneto‐/chemo‐acoustic mechanisms (~9%), each shaped by distinct fabrication approaches. Photolithography produces sharp fins for high‐Re streaming; soft lithography forms gas‐tight cavities for cavitation; two‐photon and micro‐DLP printing achieve nanometer‐scale smoothness for radiation‐pressure traps; and emerging multimaterial printers combine rigid acoustic chambers with magnetic or catalytic components. Three themes recur: (i) geometry–material–control co‐design consistently outperforms sequential prototyping; (ii) scalability and biocompatibility remain major barriers, with ad hoc quality metrics; and (iii) inverse‐design algorithms and closed‐loop acoustic imaging are accelerating optimization. This review maps fabrication techniques to actuation demands and application contexts, offering a consolidated roadmap toward clinically and industrially viable acoustic microrobots.