Electrospinning Device for Nanofibers| An Integrated Janus Bioelectronic Bandage for UnidirectionalPumping and Monitoring of Wound Exudate

Shenzhen University Professor Xue-Ji Zhang & Associate Professor Tai-Lin Xu & Assistant Professor Cong-Hui Liu: Multifunctional Wound Dressing for Directional Exudate Removal, Antibacterial Properties and Electrochemical Sensing

Chronic wounds (e.g., diabetic ulcers, pressure sores) are difficult to heal due to high-glucose environments, bacterial infections, and excessive exudate causing prolonged inflammation. Traditional gauze dressings passively absorb exudate but easily reach saturation, exacerbating periwound maceration and infection risks. Exudate contains biomarkers like glucose and uric acid whose dynamic changes reflect wound status: elevated pH indicates bacterial colonization, while abnormal glucose levels impede healing. Single-function dressings show limited therapeutic effects for chronic wounds. Therefore, developing multifunctional smart dressings combining directional exudate removal, antibacterial treatment, and multi-parameter electrochemical sensing is crucial for chronic wound care.

Recently, Professor Xue-Ji Zhang's team at Shenzhen University published a study titled "An Integrated Janus Bioelectronic Bandage for Unidirectional Pumping and Monitoring of Wound Exudate" in Nano Letters. Addressing slow healing, excessive exudate, and infection risks in chronic wounds, the study designed an electrospun Janus antibacterial dressing that unidirectionally pumps exudate from wound beds while detecting three physiological biomarkers using laser-engraved graphene (LEG) electrochemical sensors (Fig.1). Professor Zhang, Associate Professor Tai-Lin Xu, and Assistant Professor Cong-Hui Liu served as corresponding authors, with doctoral student Jing Wang and undergraduates Jin-Tao Ye and Zhuo-Heng Li as co-first authors. The research was supported by National Natural Science Foundation of China, Shenzhen Science and Technology Program, Shenzhen Overseas Talent Program, Guangdong Provincial Key Laboratory of Marine Microbial Cell Engineering, and Shenzhen Science and Technology Program.

Fig.1. Schematic and photograph of Janus wound bandage for exudate management and monitoring

The study developed a Janus wound dressing with asymmetric wettability, constructing a hydrophobic TPU nanofiber layer (diameter 43.46±16.85 nm) loaded with silver nanoparticles (AgNPs) on hydrophilic medical gauze via electrospinning, creating a significant wettability gradient (137.8° contact angle on hydrophobic side vs. 0° on hydrophilic side). Leveraging Laplace pressure difference and capillary forces, the dressing achieved efficient unidirectional exudate transport (2.2 s/drop) from hydrophobic to hydrophilic side, with 93.7% liquid absorbed by the hydrophilic layer and only 2.28% residual moisture. Uniformly distributed AgNPs (~1 nm) provided excellent antibacterial properties (>99.5% antibacterial rate) (Fig.2).

Fig.2. Unidirectional pumping characterization of Janus dressing

Laser engraving technology prepared flexible 3D porous graphene (LEG) electrode arrays, with Raman spectroscopy (ID/IG=0.476) confirming high-quality graphene formation. The sensor array comprised three working electrodes (3 mm diameter), one counter electrode, and one reference electrode, achieving optimal performance after 30% power optimization while maintaining structural integrity. Performance tests showed: glucose sensor exhibited good linearity (R²=0.996) in 0-14 mM range with 0.15 mM detection limit; uric acid sensor showed linear response (R²=0.964) in 100-600 μM range with 6.85 μM detection limit; PANI-modified pH sensor achieved 60.76 mV/decade sensitivity in pH 4-8 range, approaching Nernstian response. All sensors demonstrated excellent anti-interference capability and stability for in-situ multi-parameter monitoring of wound exudate (Fig.3).

Fig.3. Performance of laser-engraved graphene electrochemical sensors

In mouse full-thickness skin defect models, the Janus bioelectronic bandage showed significant healing promotion. The TPU/Ag group began scabbing by day 3, achieving 90.35% wound closure after 14 days - significantly higher than TPU group (88.46%) and control (76.33%). Histological analysis revealed TPU/Ag group had 87.67±8.16 μm neodermis thickness and 61.09% collagen deposition, outperforming other groups. The integrated electrochemical sensors successfully enabled in-situ dynamic monitoring of wound microenvironment for 3 days (Fig.4).

Fig.4. Janus bioelectronic bandage for wound healing and monitoring in full-thickness wound model

Paper link: https://doi.org/10.1021/acs.nanolett.4c06147