TY  - JOUR
T1  - A Hydrophilic/Hydrophobic Janus Membrane Based on Directionally Frozen Polyvinyl Alcohol Hydrogel for Dural Defect Repair 
AU  - Wei, Sirui
AU  - Liu, Hanyuan
AU  - Zhang, Baowen
AU  - Jiang, Xiaobing
AU  - Jiang, Hao
JF  - Neurosurgical Subspecialties
VL  - 2
IS  - 2
SN  - 3067-6150
SP  - 66
EP  - 78
Y1  - 2026-06-30
DO  - 10.14218/NSSS.2025.00045
UR  - https://www.xiahepublishing.com/3067-6150/NSSS-2025-00045
AB  - Background and objectives 
Cerebrospinal fluid leakage and postoperative tissue adhesion are serious complications following dural injury. Current dural substitutes often lack the functional asymmetry of the native dura mater. This study aimed to develop a hydrophilic/hydrophobic Janus polyvinyl alcohol (PVA) hydrogel membrane with a directional structure and dual functionality for effective dural defect repair.
Methods
A PVA hydrogel with an aligned porous architecture was fabricated via directional freezing combined with salt leaching, and thermal annealing was applied to enhance mechanical strength and structural stability. The hydrogel was asymmetrically modified to obtain a Janus membrane. Morphology, mechanical properties, degradation, swelling, wettability, in vitro biocompatibility, and cell migration were evaluated by the NIH-3T3 mouse fibroblast cell line. In vivo biocompatibility was assessed using a rat subcutaneous implantation model, including blank control, Durepair®, frozen-salted PVA, and Janus-PVA groups, with 5 rats in each group. Dural repair efficacy was evaluated in a rat cranial dural defect model, including untreated defect control, frozen-salted-annealed PVA, and Janus-PVA groups, with 15 rats in each group.
Results
The Janus membrane exhibited high tensile strength (8.93 ± 1.46 MPa), slow degradation (1.42% mass loss at 28 days), and low swelling (58.13% water content at 28 days). It displayed distinct bilateral wettability, and effectively blocked fibroblast migration on both sides, acting as a physical barrier against fibroblast-driven adhesion. In the rat dural defect model, the Janus membrane reduced cerebrospinal fluid leakage and brain–dura adhesion compared with the untreated defect and frozen-salted-annealed PVA control groups.
Conclusions
The engineered hydrophilic/hydrophobic Janus PVA hydrogel membrane mimics the functional asymmetry of the native dura mater and may serve as a promising candidate for further evaluation as a dural repair material.