Fabrication and In Vivo Microanastomosis of Vascularized Tissue-Engineered Constructs

Generation, Endothelialization, and Microsurgical Suture Anastomosis of Strong 1-mm-Diameter Collagen Tubes

“…It should also be noted that the native vessels in the current study were directly anastomosed to collagen scaffold with suture, which is the current clinical standard for graft implantation. To the best of our knowledge, nearly all other studies that claim anastomosis between an engineered collagen-based scaffold and native vessels £1 mm outer diameter used a polymer mesh to reinforce the anastomosis, 29 or surgical glue in place of suture. 26 Only a few groups have engineered implantable vascular grafts at the £1 mm scale.…”

Biofabrication of Vascular Networks

“…In those situations where the matrix environment in which the channels are formed is rigid or not able to be remodeled by the cells, the "vessels" formed are merely lined walls of fixed vascular dimensions. Recognizing the need for vessel adaptability in maturing microvascular networks, more native matrices (e.g., collagen), are being employed with the idea that the vascular cells can remodel channel dimensions and/or undergo angiogenesis thereby forming new vascular connections between preformed channels [57,58]. Related approaches formed channels using fine threads or needles as mandrels for microvessel-sized channels in combination with microfluidic platforms [59,60].…”

“…Once cast in the correct topology and surrounded by matrix, these materials are then flushed out of the system leaving behind open conduits, which are subsequently sodded with vascular cells. This same sacrificial approach was used to form implantable microvascular networks using patterned Pluronic hydrogel placed in a collagen matrix as the channel-forming material [58]. In this most recent approach, the prebuilt microvasculature was incorporated into the host circulation via anastomotic attachments to a feed artery and vein, thereby providing immediate perfusion of the fabricated vascular system.…”

“…However, for most preformed microvasculatures, this is difficult due to the small caliber of vessels involved. One strategy employs incorporating larger caliber inflow and outflow segments (artificial and native) into the network design that can be microsurgically anastomosed into the host circulation [2,58]. In the absence of these larger segments, integration with the host circulation relies on the spontaneous inosculation between microvessel segments of the implant vasculature and surrounding host vasculature.…”

Fabrication of capillary-like structures with Pluronic F127® and Kerria lacca resin (shellac) in biocompatible tissue-engineered constructs

“…In order to overcome these limitations, we have developed a method for the fabrication of biocompatible tissue‐engineered constructs that recapitulate the hierarchical organization of an arteriole, venule and capillary bed (Hooper et al ., ). Employing our previously described sacrificial microfibre technique, we exploit the differential solubilities of melt‐spun Kerria lacca resin (shellac) and manually extruded Pluronic® F127 (both FDA‐approved materials for clinical use) microfibres to create a dense tangle of microchannels, measuring 5–500 μm in diameter, which coalesce into a macro‐inlet and ‐outlet (Bellan et al ., ; Miller et al , ).…”