Fig. 1.

Setup for thiol-Michael addition hydrogel synthesis at clinically relevant volumes. A Dual chamber syringe mixer for synthesizing hydrogels upon injection. Precursor solutions were separately preloaded into each syringe barrel at equal volumes. The plungers were pushed simultaneously to mix the solutions in a 1:1 ratio through the Y connector tube and static mixer before dispensing through the adjustable nozzle. B Development of agarose resection phantoms. PLA holder frames were placed in a silicon mold. A resin printed solid cylinder was positioned over the PLA frame with a clamp while 1% agarose solution was poured into the PLA holder. After gelation, the cylinder was removed to generate a cavity in the agarose hydrogel that measured 3 cm in width and 2.55 cm in height. C Healthy porcine brain tissue surrogates for ultrasound imaging without cranial implant. The probe was positioned on top of the porcine brain tissue surrogates in agarose resection phantoms. Scale bar is 1 cm. D Ultrasound imaging of porcine brain tissue surrogates through cranial implant. The cranial implant was placed over the top of the porcine brain tissue surrogates and the ultrasound imaging probe was positioned over the cranial implant to obtain B-scan images of the surrogate through the implant.