Background. Protocols using chemical reagents for scaffold decellularization can cause changes in the properties of the matrix, depending on the type of tissue and the chemical reagent. Technologies using physical techniques may be possible alternatives for the production grafts with potential superior matrix characteristics. Material and Methods. We tested four different technologies for scaffold decellularization. Group 1: high hydrostatic pressure (HHP), 1 GPa; Group 2: pressure shift freezing (PSF); Group 3: pulsed electric fields (PEF); Group 4: control group: detergent (SDS). The degree of decellularization was assessed by histological analysis and the measurement of residual DNA. Results. Tissue treated with PSF showed a decellularization with a penetration depth (PD) of 1.5？mm and residual DNA content of . HHD treatment caused a PD of 0.2？mm with a residual DNA content of . PD in PEF was 0.5？mm, and the residual DNA content was . In the SDS group, PD was found to be 5？mm, and the DNA content was determined at . Conclusion. PSF showed promising results as a possible technique for scaffold decellularization. The penetration depth of PSF has to be optimized, and the mechanical as well as the biological characteristics of decellularized grafts have to be evaluated. 1. Introduction Currently, major drawbacks of prosthetic heart valves or artificial patch material, as well as aortic allografts, are lack of remodeling and growth potential and also degeneration and calcification [1, 2]. Tissue engineering is a promising technology to overcome the current limitations of existing prosthetic valves. Decellularized allogenic or xenogenic tissue is one of the preferred scaffold matrices for cardiovascular tissue engineering [3–5]. One major goal of ongoing research is implanting these matrices into the body having a curing effect. These decellularized matrices could be either seeded with autologous cells ex vivo before implantation, or the decellularized matrix will be implanted with subsequent cell seeding by circulating cells. There is no doubt that at the moment seeding at all implant sites and creating really functional tissue are still problems that have to be improved. The durability, cell seeding efficiency, and the graft viability reflecting the growth potential of tissue-engineered grafts mainly depend on the quality of the decellularized scaffolds. Many techniques for tissue decellularization have been reported [6–11]. The optimal decellularization protocol should result in a strongly reduced/absent antigenicity by removing the cellular components
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