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PUBLISHED ONLINE: 2 NOVEMBER 2015 | http://dx.doi.org/10.1038/nnano.2015.238
Web End =DOI: 10.1038/NNANO.2015.238
A multiphase transitioning peptide hydrogel for suturing ultrasmall vessels
Daniel J. Smith1,2, Gabriel A. Brat3, Scott H. Medina1, Dedi Tong3, Yong Huang4, Johanna Grahammer3, Georg J. Furtmller3, Byoung Chol Oh3, Katelyn J. Nagy-Smith1,2, Piotr Walczak5, Gerald Brandacher3 and Joel P. Schneider1*
Many surgeries are complicated by the need to anastomose, or reconnect, micrometre-scale vessels. Although suturing remains the gold standard for anastomosing vessels, it is difcult to place sutures correctly through collapsed lumen, making the procedure prone to failure. Here, we report a multiphase transitioning peptide hydrogel that can be injected into the lumen of vessels to facilitate suturing. The peptide, which contains a photocaged glutamic acid, forms a solid-like gel in a syringe and can be shear-thin delivered to the lumen of collapsed vessels (where it distends the vessel) and the space between two vessels (where it is used to approximate the vessel ends). Suturing is performed directly through the gel. Light is used to initiate the nal gelsol phase transition that disrupts the hydrogel network, allowing the gel to be removed and blood ow to resume. This gel adds a new tool to the armamentarium for micro- and supermicrosurgical procedures.
Microvascular anastomosis is critical in reconstructive surgery, especially for free tissue transfer, lymphaticovenous anastomosis and perforator ap surgery1.
Although anastomosing 12 mm diameter vessels can be routinely accomplished by skilled surgeons, reconnecting micrometre-sized vessels is exceedingly difcult, even for those who specialize in vascular- or microsurgery. The procedure is time-consuming, requires sophisticated instrumentation, and there is a steep learning curve for the training surgeon2. Procedures employing the anastomosis of micrometre-sized vessels are also critical in cardiac bypass, vascular and paediatric transplant surgeries, as well as vascularized composite allotransplantation and lymphatic supermicrosurgery.Optimal vascularization allows complex procedures to be performed that were previously unthinkable and considered technically impossible. In addition to impacting patient outcome, ultrasmall anastomosis is critical in a multitude of research settings that employ animal models with small vasculature, such as mice.Although assisting devices, such as couplers, clips, cuffs, lasers and various adhesives can facilitate the anastomosis of millimetre-sized vessels, they either do not support or have not been widely adopted for vessels with ultrasmall features3.
Suturing remains the gold standard...