Accumulation, distribution, and toxicity of black phosphorus nanomaterials across biological systems: a critical review

Abstract

Black phosphorus nanomaterials (BPNMs) composed of the essential element phosphorus—including nanosheets and quantum dots—have attracted growing interest due to their distinctive structure, tunable physicochemical properties, and broad applications. However, their potential toxicity necessitates a deeper exploration of interactions with biological systems. This review systematically summarizes the current understanding of BPNM accumulation, distribution, and toxicity across multiple biological systems, ranging from microorganisms and algae to fish and mammals. These biological behaviors are strongly influenced by size, concentration, surface modifications, and degradation. Beyond summarizing existing knowledge, this review offers three novel contributions: first, it uncovers BPNM–unique reactive oxygen species (ROS) mechanisms that distinguish them from other 2D nanomaterials. Second, it differentiates BPNMs' particle-specific effects from phosphate-derived effects to deepen the understanding of their toxic mechanisms. Third, it discusses the specific molecular pathways of their toxic effects. Despite these advances, significant knowledge gaps persist regarding understanding the long-term effects and molecular mechanisms of BPNMs across organismal taxa, and their concentrations and critical environmental processes in a real-world environment. We highlight key factors regulating biological interactions, discuss the roles of surface functionalization and degradation in mitigating risks, and propose future research priorities, including field-based measurements in environmental matrices, chronic exposure studies, health effects, and thus mechanistic elucidation. This review provides a comprehensive scientific basis for assessing the environmental and health risks of BPNMs and guiding their safe applications.