Evaluating mechanical performance of hydrogel-based adhesives for soft tissue applications.

摘要

According to the National Center for Health Statistics, an estimated 22 million women have undergone a hysterectomy procedure in the United States. The most common complication during hysterectomies is accidental laceration of the urinary bladder during the surgery with incidence between 0.2-8.3% with the current gold standard wound repair method being sutures. Yet, sutures come with their own limitations in that they necessitate use of a catheter and collection bag during healing due to preventing proper distention of the bladder tissue at normal pressures. The long-term goal of our study is to eliminate the need for suturing by creating a surgical adhesive that provides a combination of strength, compliance, and biocompatibility for application to the bladder. However, current FDA-approved, commercially available tissue adhesives and sealants each have specific limitations that make them unsuitable for bladder application. While addressing the shortcomings of its predecessors, poloaxmines called Tetronic® (BASF Corporation) have been used as the backbone of a novel tissue adhesive. Previous studies using Tetronic ® have exhibited higher strengths with increasing hydrogel content, but need further refinement to meet the mechanical requirements for bladder wall tissue mechanics. Thus, it is hypothesized that incorporation of a low molecular weight poloaximine, Tetronic® 304 (T304, MW: 1650 Da) would allow further increasing of hydrogel content and could yield higher bonding and bulk strength for a tissue adhesive while not compromising gelation time. Briefly, Tetronic® 304, and 1107 (MW: 15030 Da) were reacted with acryloyl chloride to form terminal acrylate groups using previously established methods with the final product characterized through NMR spectroscopy to determine the acrylation conversion percentage. The Tetronic ® acrylate was crosslinked using dithiothreitol (DTT) with the bulk strengths of various blends of the Tetronic®-based adhesive determined via calculating maximum tensions from end-to-end tensile adhesion tests on collagen sheets. In addition, punctured rat bladder specimens sealed with two blends of the hydrogel adhesive were subjected to increasing intravesicular pressure until failure.;The maximum tension achieved from the tensile tests was for the 75/25 at 60wt% T304-acrylate/T1107-acrylate group with a value of 0.65 N/cm±0.06 N/cm (n=6). In addition, the rat bladder puncture sealed with a 50/50 blend at 50wt % withstood pressure at an average of 45.45±3.96 cm H2O. These results have demonstrated that using T304 has allowed for a higher content of hydrogel to be incorporated into the Tetronic® -based adhesive, thus increasing overall bulk strength. To further test the efficacy of this Tetronic®-based adhesive, testing the hydrogel-based adhesive on the bladder both ex vivo and in vivo using larger animal models will be necessary before moving onto clinical trials.