1/17/2024 0 Comments Perry scaffold safety manual![]() ![]() Since the act of pipetting media onto a scaffold and ensuring it saturates both the lumen and outer circumference requires both training and skill an ideal seeding system would eliminate the need for this step. 19– 22 While manual seeding techniques have proven successful in the laboratory and the clinic, they introduce the possibility of inter-operator variability as well as intra-operator variability and result in variance in the quality of seeded grafts. In animal studies, unseeded grafts are subject to higher failure rates compared with seeded grafts when implanted as inter-positional grafts. The seeding of porous scaffolds is a key step in the construction of TEVGs. ![]() The seeded scaffold was placed in the incubator for 2 h before being removed for evaluation. The seeded scaffold was transferred to a sterile container and submerged in 25 mL of autologous plasma diluted with 125 mL of PBS. Subsequent to seeding, the scaffold was removed from the seeding device and placed in a cell culture dish to partially dry for 5 min and allow for maximal cell adhesion. The vacuum was turned on for the duration of cell seeding (∼30 s). The vacuum device with the prewetted scaffold was introduced into the graduated cylinder containing the cell suspension. BM-MNC cells were suspended in 70 mL of PBS, using a 100-mL sterile graduated cylinder. The specimen trap solutions were discarded and reconnected. The vacuum was turned on to prewet the scaffold in an effort to decrease its intrinsic hydrophobicity. The vacuum device with the secured scaffold was introduced into a 100-mL sterile graduated cylinder containing 70 mL of PBS. Tubing was used to connect the vacuum device to the proximal specimen trap ( Fig. The scaffold was secured onto the outer perforated sleeve by wrapping a transparent adhesive dressing called tegaderm ™ around both edges creating an airtight seal. The biodegradable scaffold was introduced over the outer perforated section of the vacuum-seeding device. The vacuum-seeding device was assembled in the hood by attaching the outer perforated sleeve to the inner suction core ( Fig. Suction tubing was connected to two 70-mL specimen traps, which in turn were connected to a pressure regulator connected to house suction via suction tubing and placed inside the hood. In this investigation we present an intra-luminal vacuum seeding technique that does not require rotation for use with BM-MNCs and the achievement of a rapid, operator-independent, and self-contained cell seeding technology capable of clinically viable construction of TEVGs with similar cellular distribution, attachment, and viability to that of manually seeded grafts. 14– 17 These external vacuum pressure systems require infused intra-luminal media and more recently dynamic rotation of the scaffold during seeding. Vacuum seeding first emerged in the early 1990s, but has generally consisted of a cell suspension-filled scaffold under extra-luminal vacuum pressure. Several seeding techniques, including rotational, 5, 6 centrifugal, 7, 8 magnetic, 9, 10 and electrostatic, 11– 13 have been developed to optimize cell seeding, but as of yet no technique as far as we know has been able to fulfill all the requirements of an ideal, clinically useful seeding system and achieve approval by the Food and Drug Administration (FDA) for use in TEVGs. 3, 4 The development of an operator-independent method for seeding autologous BM-MNCs, which achieves similar cellular viability, distribution, and attachment to the scaffold as previous methods, is an important next step in the translation of this technology from the bench to the clinic. While the technique proved to be both safe and effective in our initial pilot study, its ultimate clinical utility was limited by inter- and intra-operator variability. The seeded scaffold was then statically incubated in autologous serum for 2 h before implantation. ![]() Briefly, our TEVG was assembled by pipetting a concentrated suspension of autologous bone marrow-derived mononuclear cells (BM-MNCs) of ∼300,000 cells/cm 2 onto a biodegradable scaffold fabricated from a knitted polyglycolide fiber tube coated with a 50:50 copolymer sponge of L-lactide and ɛ-caprolactone. In this pilot study, our TEVG was assembled as described by Shin'oka et al. Results of this pilot study demonstrated no graft-related mortality with acceptable safety and efficacy and the added benefit of growth potential, making them the first human-made vascular graft with growth potential. In this pilot study we evaluated the use of TEVGs as conduits for use in congenital heart surgery, where their growth potential could be used to its fullest potential. W e performed the first clinical trial evaluating the use of tissue-engineered vascular grafts (TEVGs) in humans. ![]()
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