The development of multifunctional sensors that combine accurate disease diagnosis with effective antibacterial activity represents a significant advancement in the field of human health. Such sensor systems hold particular value for the early detection of critical biomarkers and the simultaneous mitigation of bacterial contamination. However, the design of a single platform capable of fulfilling both objectives remains a prominent challenge.
A research team from Harbin Normal University in China has developed a novel nanoreactor that enables dual-mode biomarker detection and effective antibacterial treatment. This technological advance presents a versatile tool that holds significant promise for enhancing clinical diagnostic efficacy and providing robust support for combating pathogenic infections.
The team published their research article in the journal Polyoxometalates on September 10, 2025.
Constructing a nanoreactor
The nanoreactor, named PW12@ZIF-67-Au (PZA), is constructed by encapsulating phosphotungstate (PW12) within a zeolitic imidazolate framework (ZIF-67) while modifying its surface with gold nanoparticles (AuNPs). This design leverages the unique properties of each component to create a system with oxidase-like activity, enabling it to catalyze reactions without the external oxidants like hydrogen peroxide.
“We designed this nanoreactor to serve as an all-in-one platform for both sensing and antibacterial applications,” said Fang Chai, corresponding author of the study and professor at the College of Chemistry and Chemical Engineering, Harbin Normal University.
“Its ability to detect low levels of biomarkers like DA and AFP while also combating bacterial infections makes it highly suitable for the early diagnosis and treatment of relevant diseases.”
Detection of dopamine
The team demonstrated that the PZA nanoreactor enables the detection of DA within the concentration range of 0.3–20 μM via a colorimetric method, with a detection limit as low as 183 nM. Meanwhile, when integrated into an electrochemical immunosensor, PZA facilitates the detection of AFP across the concentration range of 0.01–100 ng/mL, achieving a low detection limit of 7.65 pg/mL. Both detection methods exhibited high accuracy in human serum samples, and their recovery rates were comparable to those of the clinical standard enzyme-linked immunosorbent assay (ELISA).
Furthermore, the PZA nanoreactor exhibited robust antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), achieving a bacterial killing efficiency of over 90% when applied at a concentration of 200 μg/mL. This effect is driven by the generation of reactive oxygen species (ROS), and these ROS exert their bactericidal action by disrupting the integrity of bacterial cell membranes.
“The confined microenvironment within the ZIF-67 framework enhances the stability and reactivity of the polyoxometalate clusters, while the AuNPs improve electron transfer and biocompatibility,” explained Fang Chai.
Smartphone readout
The researchers also integrated the colorimetric detection system with a smartphone-based readout, allowing for portable, real-time monitoring of dopamine levels. This feature underscores the potential of the technology for use in resource-limited settings.
The study not only puts forward a novel strategy for the design of multifunctional nanomaterials with antimicrobial activity but also broadens the application scope of POM-based nanomaterials. It not only presents promising prospects for clinical diagnostic practices but also further extends the application of POM-based composites in the field of biosensing.
Other contributors include Yawen Guan, Wei Tang, Yuting Zhao, Shuo Li, Li Wang, Miaomiao Tian, and Yanfei Li from Harbin Normal University.
This work was supported by the National Natural Science Foundation of China (No. 22171060), the Excellent Young Teachers Research Support Program of Education Department of Heilongjiang Province (No. YQJH2024102), Graduate Innovation Fund of Harbin Normal University (No. HSDBSCX2024-10), and Department of Science and Technology of Heilongjiang Province (No. PL2024B003).
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