Modulation of mechanical properties in multiple-component tissue adhesives

Abstract

In vitro, ex vivo, and in vivo studies were performed to investigate the effect of mixing upon the mechanical properties of a two-component tissue adhesive. The hypothesis investigated was that a more complete mixing of the two components would yield an increase in the mechanical performance of the adhesive. This in turn would be demonstrated by improved outcomes in models of clinical sealant application. In vitro stereological analysis of tissue adhesive mixed and delivered by several different applicators demonstrated variation in the amount of mixing provided by each type of delivery system. Ex vivo tensile adhesive strength showed that there was a correlation between the amount of mixing and bonding strength; that is, more thorough mixing demonstrated higher adhesive strength. No significant difference was seen, however, between the different applicator types and impact on in vivo dermal incisional closure strength. There was a correlation, though, in amount of mixing and in vivo hemostasis. In a rabbit spleen incision model, a more thoroughly mixed sealant corresponded with a decrease in time to obtain complete hemostasis, as well as less sealant used. The effects of mixing on tissue-adhesive mechanical performance were influenced somewhat by the amount of mixing provided by the applicator. This effect, however, was dependent upon the sealant formulation and the type of in vivo application.

The development of photochemically crosslinked native fibrinogen as a rapidly formed and mechanically strong surgical tissue sealant

“…Adequate adhesion was achieved 45-fold faster, requiring 20 s of visible light illumination compared with a minimum 15 min curing required for tissue adhesion using the commercial fibrin sealant. Sierra et al [15] carried out similar measurements using fibrinogen (60 mg/ ml)/thrombin sealants and porcine dermal grafts, achieving adhesive strengths of only 28-38 kPa. Other studies of fibrinogen/ thrombin tissue sealants at a range of concentrations and curing times and temperatures give results that are not easily compared to our results because the method of measurement of adhesive strengths varied, however results were all below 30 kPa and generally about 6 kPa ( Table 1).…”

The optimal technique for combined application of fibrin sealant and bioabsorbable felt against alveolar air leakage☆☆☆

“…When the F solution is rubbed over the pleural defect area, as the first step of the covering technique, it penetrates the tissue. This step is important because permeation of the highly viscous F solution into the lung tissue by simple dripping or spraying is difficult [13]. The subsequent attachment of the thrombin-impregnated felt sheet over the fibrinogen-rubbed area enables direct tissue permeation of the less-viscous T solution that then reacts with the fibrinogen to form a fibrin clot in the tissue.…”

“…The concomitant spraying of two fibrin sealant components was developed to improve the sealing effect by achieving a more homogeneous and efficient mixture of the two components than that obtained by their sequential application [4,13,15]. However, the spray application of the two components over the dry PGA felt might result in rapid clot formation concurrent with the mixture of two sealant components, thereby leaving air spaces within the felt microstructure and causing an inadequate supply of thrombin to the tissue.…”

“…It has been reported that fibrin sealants with higher concentrations of fibrinogen produce stronger clots [13,16,17], whereas those containing higher concentrations of thrombin form clots more rapidly [16]. Furthermore, factor XIII increases the tensile strength and stability of the clot [18].…”

“…Thrombin (T) solution comprises thrombin reconstituted in calcium chloride solution. The mechanism of clot formation by fibrin sealant has been well described previously [11][12][13]. Bioabsorbable polyglycolic acid (PGA) felt used in this study was 0.15-mm-thick NEOVEIL W sheet (Gunze Co., Kyoto, Japan).…”