On June 25th, the paper entitled: “A reusable hydrogel biosensor array with electrically responsive hydrogel interfaces for non-invasive locating of perforating arteries” was published online in Science Advances. Ganguang Yang and Yuqi Qiu are co-first authors. Professor Hao Wu and Professor Zhouping Yin serve as corresponding authors, with Dr. Yutian Liu from HUST-affiliated Union Hospital contributing as a co-corresponding author.
In the field of medical health monitoring, conventional commercial monitoring systems are mainly composed of rigid modules, which exhibit poor flexibility and weak adhesion, hindering seamless integration with the skin. These systems are also prone to motion artifacts, significantly compromising signal fidelity. In recent years, flexible electronic systems fabricated with soft materials have demonstrated exceptional stretchability and mechanical adaptability, facilitating conformal attachment with skin. Besides, these flexible devices combined with silicon-based chips for physiological signal monitoring have shown great promise in wearable devices, health monitoring, and human-machine interfaces. However, current flexible electronic systems still face critical challenges: (1) high manufacturing costs for materials and devices; (2) risks of cross-contamination or functional degradation after prolonged use due to contamination or material deterioration, severely limiting their practical applications. Thus, there is an urgent need to develop reusable, flexible electronic systems that combine precision, ease of operation, and skin compatibility.
To address these challenges, the research team led by Professors Hao Wu and Zhou-Ping Yin proposes a universal electric-field-induced strategy. This study develops a novel electric-field-responsive hydrogel interface layer, enabling rapid detachment/reassembly of the device/hydrogel interface, thereby granting the flexible electronic system reusability. Furthermore, the electric field-induced adhesion enhancement at the hydrogel/skin interface ensures high-fidelity signal acquisition. The hydrogel-based biosensor system is further used for locating perforating arteries (PAs). Clinical results demonstrate that the hydrogel sensor array can accurately and rapidly locate PAs in various types of free flaps. Through the electric field-triggered disassembly of hydrogel interfaces, the flexible sensors achieve reusable functionality. This hydrogel interface design strategy not only mitigates cross-contamination risks but also substantially reduces device costs, offering a novel approach for developing reusable flexible electronics in biomedical applications.
Fig. 1. Design of the reusable hydrogel biosensor array
This study proposes a universal electric field-induced strategy to achieve the detachable hydrogel/device interface. The hydrogel interface layer forms robust bonding with poly(acrylic acid) (PAAc)-modified flexible circuit substrates through Fe³⁺-carboxyl coordination bonds. Upon electric field application, the device/hydrogel interface undergoes a gel-sol transition, reducing the interface bonding strength by 117-fold and enabling rapid hydrogel detachment. Subsequently, a new hydrogel layer can be reassembled onto the system to achieve the reusability of flexible circuits. This versatile strategy can be extended to both simple flexible sensors and complex flexible electronic systems.
Fig. 2. Electrically triggered rapid detachment of the device/DGMH interface layer
This study demonstrates the clinical efficacy of reusable hydrogel biosensors for precise PA locating. The results show that the hydrogel biosensor array achieves localization accuracy comparable to the gold-standard CT angiography (CTA) without producing false-positive outcomes, surpassing conventional handheld Doppler ultrasound (ADS) in diagnostic reliability. Furthermore, the array enables rapid mapping of single or multiple perforators in both upper and lower extremity flap donor sites within 4 minutes, regardless of flap type. For clinical implementation, the system incorporates an electric field-assisted hydrogel interface replacement mechanism. This allows for controlled detachment and re-bonding of new hydrogel layers, enabling biosensor array reuse while effectively mitigating cross-contamination risks and reducing overall healthcare costs.
Fig 3. Reusable Hydrogel biosensor array for PA locating
The above research work was supported by the National Natural Science Foundation of China (No. 52188102, 52350121, 52475018, and 82201548) and the STAR Project by the School of Mechanical Science and Engineering of Huazhong University of Science and Technology.
Original link：https://www.science.org/doi/10.1126/sciadv.adw6166
