Microplastics-Mediated Gut Microbial Dysbiosis and Cellular Bioenergetic Impairment: A Critical Review

Plastics are an integral part of modern society; however, their environmental persistence has led to widespread contamination, posing significant ecological and human health risks. Microplastics (MPs) and nanoplastics (NPs) raise concerns because of their small size and ability to penetrate biological systems, leading to concerns about bioaccumulation and toxicity. This review examines the sources, classification, and fate of MPs in the environment, their entry routes into the human body, organ accumulation, and health impacts, with a focus on gut microbiota, oxidative stress, and energy metabolism. A comprehensive literature analysis was conducted to assess MPs' occurrence in the environment, major exposure pathways-including ingestion, inhalation, and dermal absorption-and their accumulation in human tissues. Additionally, experimental findings on MPs' role in gut dysbiosis, metabolic disturbances, and inflammatory responses are discussed. MPs have been detected in various biological matrices, including the gastrointestinal tract (GIT), bloodstream, lungs, and placenta, raising concerns about their long-term health implications. However, inconsistencies in detection methods hinder standardization. Future research should focus on developing advanced analytical techniques, such as super-resolution and cryo-electron microscopy, as well as spectroscopic and mass spectrometry-based methods like surface-enhanced Raman spectroscopy (SERS) and single-particle ICP-MS, to improve sensitivity and specificity in the detection of MPs in biological and environmental samples. Policy interventions, stricter plastic regulations, improved waste management, and public awareness campaigns are crucial for mitigating MPs' exposure and safeguarding environmental and human health.