Current Journal of Applied Science and Technology

Nature is routinely invoked as a design archive for medicine and engineering, and the volume of work claiming biological inspiration has expanded faster than the evidence needed to evaluate it. This critical narrative review examines how cues drawn from living systems have been converted into biomedical and engineering technologies, and asks how far the resulting performance claims withstand scrutiny. The review is deliberately cross-domain. It covers interfacial mimicry, including fibrillar and wet adhesion, liquid repellency, atmospheric water capture and contact-mediated antibacterial surfaces; structural mimicry, including hierarchical toughening architectures, protein fibres, structural colour and radiative thermal control; behavioural and systems mimicry, expressed in soft and bioinspired robotics; and molecular or cellular mimicry, expressed in membrane-camouflaged carriers, matrix-mimetic scaffolds, bioprinted constructs and organ-on-chip platforms. Literature was identified through openly accessible scholarly indexes and bibliographic registries, appraised for design adequacy, measurement validity, replication and external validity, and synthesised thematically rather than catalogued. Three findings recur across otherwise unrelated fields. First, the strongest evidence is almost always mechanistic and laboratory-scale, whereas evidence of durable performance under service conditions, and of clinical benefit, is comparatively sparse. Second, the absence of shared metrology means that headline performance figures are frequently incommensurable between laboratories, which obstructs meta-analytic aggregation and encourages selective reporting. Third, the term mimicry is used far more loosely in engineering than in evolutionary biology, where it denotes a specific signalling relationship, and this semantic drift allows superficial resemblance to be presented as functional equivalence. Areas of comparatively secure evidence include hierarchical toughening in ceramic composites, contact-mediated bacterial killing on nanostructured surfaces, and catechol-based wet adhesion chemistry. Areas of weak or contested evidence include durability of liquid-repellent coatings, sustainability claims attached to biomimetic design, and the assumption that data-driven design tools resolve rather than relocate the underlying validation problem. The review proposes prioritised research directions centred on standardised reporting, service-condition testing and preregistered comparative studies.