Development and thermo-mechanical characterization of cyanoacrylate-based tissue adhesives

Tissue adhesives are crucial in current medical practice, facilitating the healing process in traumatic lacerations and surgical incisions. This work aims to develop and characterize tissue adhesives based on cyanoacrylate-based n-butyl and octyl blends. The characterization of three different formulations was achieved through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC). FTIR spectra were obtained between 200 and 4000 cm-1, and the results indicated the presence of specific functional groups, specifically for the base monomers of the formulas between 1000 and 1200 cm-1. The samples started to degrade around 160 degrees C and were completely degraded between 200 and 250 degrees C. Viscosity analysis showed that the shear rate range was from 300 to 1 s-1, while the temperature varied between 20 and 37 degrees C. Dynamic Mechanical Thermo-Analysis (DMTA) showed similar storage and loss modulus under a temperature range of 0-80 degrees C. In contrast, a commercial standard sample, utilized as a comparison standard, showed the lowest values, about 25% less than other samples. Oscillatory rheology performed under 37 degrees C and varying the deformation amplitude (0-100%) with an oscillation frequency of 5 rad/s allowed a comparison between the samples evaluated and the results from DMTA testing. Mechanical characterization was achieved through a comparison between these results and the correspondent results of mechanical testing as per ASTM standards applicable to tissue adhesives-F2258-05, F2255-05, F2256-05, and F2458-05. They suggest the utilization of a viscous n-butyl and 2-octyl cyanoacrylate-based blend, allying a better degree of biocompatibility with adequate mechanical performance.