Reusable Nanomaterial Sterilizes Contaminated Milk and Water 100% in Minutes, Maintaining Over 99% Efficacy for Five Cycles

August 30, 2026

AZoNano International

Overview

Researchers have developed a reusable multilayer MCOF@Au@PEI nanomaterial that effectively sterilizes contaminated milk and drinking water within minutes. This magnetic, gold-containing nanomaterial captures bacteria and converts near-infrared light into heat for sterilization. In laboratory tests, it achieved 100% sterilization of *E. coli*, *S. aureus*, and *S. typhimurium* in 435 seconds, maintaining over 99% efficacy for five cycles.

In Depth

Key Findings

As reported by AZoNano, researchers have successfully developed a reusable multilayer MCOF@Au@PEI nanomaterial capable of efficiently sterilizing contaminated milk and drinking water in a matter of minutes. This innovative magnetic nanomaterial captures bacteria and leverages near-infrared light to generate heat, achieving rapid and thorough sterilization.

Technical / Clinical Details

The developed MCOF@Au@PEI nanomaterial is a magnetic composite with a multilayer structure, surface-modified with gold (Au) and polyethyleneimine (PEI). This material functions through three primary mechanisms. First, the PEI layer electrostatically interacts with the negatively charged surfaces of bacteria, enabling efficient capture. Second, the gold nanoparticles within the material absorb near-infrared (NIR) light, converting it into thermal energy. This photothermal effect exposes captured bacteria to localized high temperatures, causing damage to cell membranes and denaturation of proteins, leading to inactivation. Finally, due to its magnetic properties, the material can be easily separated and recovered from the treated liquid using a magnetic field, allowing for multiple reuse cycles. Rigorous laboratory tests demonstrated that this nanomaterial achieved 100% sterilization of common pathogenic bacteria—*E. coli*, *S. aureus*, and *S. typhimurium*—in water and milk within just 435 seconds. Furthermore, it exhibited remarkable durability, maintaining over 99% sterilization efficacy even after five reuse cycles.

Background & Context

The global supply of safe drinking water and food remains a pressing public health concern. In particular, in developing regions and during disaster situations, bacterially contaminated water and milk can lead to infectious diseases and severe health consequences. Conventional sterilization methods (e.g., boiling, chlorination, UV irradiation) present challenges such as time and energy costs, residual chemicals, risk of recontamination, or the need for large-scale infrastructure. This reusable, rapid, and highly efficient nanomaterial offers a groundbreaking solution to these challenges, specifically addressing the need for decentralized, low-cost water and food sterilization.

Strategic Significance & Outlook

This MCOF@Au@PEI nanomaterial holds significant promise for improving public health and enhancing food security. Its reusability and rapid sterilization capabilities are expected to find broad applications, particularly in drinking water supply systems in remote areas or regions with unstable power grids, as well as in quality control for milk in the dairy industry. Future efforts will focus on scaling up the technology, conducting long-term environmental impact assessments, and validating its efficacy and safety in real-world settings. This advancement is poised to be widely adopted as a practical solution to global health challenges.

Source: https://www.azonano.com/news.aspx?newsID=41807

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