Aging transforms marine microplastics into reactive interfaces with environmental consequences

Microplastics are pervasive contaminants in marine ecosystems and pose widespread threats to marine organisms and ecological processes. Diverse environmental stressors trigger microplastic aging through photooxidation, mechanical abrasion, and microbial colonization, which reshapes their physicochemical and biological traits. Aging induces polymer degradation, chemical group transformation, and increased surface roughness, greatly enhancing interfacial reactivity and adsorption toward heavy metals, organic pollutants, and antibiotics. It also alters microplastic transport, bioavailability, and toxicity, leading to cascading marine ecological risks. This review summarizes recent advances in marine microplastic aging mechanisms and surface evolution. An "interface reprogramming" framework is proposed to clarify how aging governs microplastic behaviors, pollutant interactions, and ecological fates. These findings deepen the understanding of microplastic hazards and support science-driven strategies for marine pollution mitigation.