Hydrogels with brain tissue-like mechanical properties in complex environments

In surgical training and experimental research, brain tissues immersed in cerebrospinal fluid often exhibit complex deformation and strain rate effects that can compromise their reliability and stability. Therefore, it is essential to develop a high-fidelity human brain tissue simulant material that serves as a physical surrogate model to understand its mechanical behavior, such as traumatic brain injury (TBI). However, the existing sim-ulant materials have failed to meet the required mechanical properties. This study presents a composite hydrogel consisting of both a rigid polysaccharides network (Sodium alginate and Pectin) and a flexible polyacrylamide network, exhibiting brain tissue-like mechanical properties under various solution environments and strain rates. The results show that nonlinear mechanical behavior and good similarity under various external environments (artificial cerebrospinal fluid, normal saline, deionized water, and air environments) and different strain rates (0.001 s-1,900 s-1,1700 s-1). By analyzing the experimental data and theoretical analysis, we examine the ef-fects of complex environments on the mechanical behavior of composite hydrogel and porcine brain tissue. Given that the properties of human brain tissue resemble those of porcine brain tissue, our work has significant reference value in realizing surgical training and advancing related research in biomedical engineering.