Functionalized microalgae as emerging composite bioproducts for biomedical applications: Design, fabrication and prospects

The transformation of abundant bioresources into versatile bioproducts is the cornerstone of modern bioeconomy. Microalgae are sustainable bioresources traditionally used for biofuels and food supplements. Additionally, their unique structure and physiological characteristics make them promising platforms for high-value bioproducts. While the potential of microalgae-based smart and functional materials is rapidly expanding, the direct utilization of microalgae biomass faces inherent limitations in biomedicine, including inadequate targeting specificity, suboptimal bioavailability, and limited functionality under native conditions. Therefore, the controlled assembly of microalgae with polymers, nanoparticles, and therapeutic drugs to manufacture microalgae-based composite bioproducts is critical for unlocking their potential in precise diagnosis and therapy. This review presents structural design strategies and recent applications of functionalized microalgae bioproducts in biomedical scenarios, linking functionalization strategies to performance considerations, focusing on fabricating advanced composite bioproducts from raw bioresources. Specifically, functionalized microalgae enable lesion-localization imaging, biosensing and real-time monitoring in diagnostics; promote wound healing, resist harmful substances, and address emergencies like myocardial ischemia in therapeutics; and achieve targeted drug delivery, enhanced efficacy of photodynamic, photothermal and sonodynamic therapy in theranostics. Finally, the technical and clinical translation bottlenecks of functionalized microalgae are discussed, emphasizing interdisciplinary solutions spanning bioresources to biomedicine, aiming to provide actionable insights for researchers in related fields.