Design, Validation, and Early In Vivo Testing of an Electric Bioreactor for Conditioning of Plant-Based Vascular Grafts

Small-diameter vascular grafts remain limited by thrombosis, incomplete endothelialization, and insufficient cellular organization. Plant-based vascular grafts are an emerging scaffold platform that uses decellularized plant microarchitecture and cellulose-rich matrices, but their translation requires controlled pre-implant conditioning strategies that organize seeded endothelium without compromising cell viability. Here, we developed and evaluated a model-informed electric-perfusion bioreactor for conditioning endothelialized plant-based vascular grafts. Multilayer grafts were fabricated from decellularized leatherleaf scaffolds, characterized by sequential gravimetric fractionation and qualitative gas chromatography-mass spectrometry, and conditioned in a custom parallel-plate electric-field chamber that supports electrical stimulation, luminal perfusion, or combined electric-perfusion conditioning. Analytical electric-field modeling was used to estimate local graft-region exposure and guide selection of biologically tolerated stimulation conditions. A 24 h live/dead screen identified 0 to 70 V/m as a biologically tolerated range using a study-defined 90% viability screening criterion; normalized viability fell below this threshold at 80 and 90 V/m, with a sharp decrease to 51% at 100 V/m. Within this range, electrical stimulation, flow conditioning, and combined electric-perfusion conditioning each produced measurable endothelial organization by scanning electron microscopy (SEM) and CellProfiler-based morphology analysis. Endothelialization and flow conditioning also reduced 0.45 µm bead penetration into the middle graft layer, supporting bead permeability as an early barrier-associated readout. Plant grafts conditioned in vitro with electrical stimulation and flow were subsequently evaluated in a pilot abdominal aorta interposition study in male Sprague-Dawley rats. The pilot study supported surgical feasibility and enabled descriptive Doppler ultrasound assessment of graft-region flow and functional patency at the 3-month endpoint. Together, these findings establish a model-informed platform for integrating electrical and perfusion cues in plant-based vascular graft culture and define biologically tolerated operating conditions for future studies of graft function, remodeling, and patency.