Comprehensive characterization of the effect of tissue storage conditions on tissue-adhesive interaction

In the evaluation of tissue adhesives, freshly harvested tissues are the most relevant to clinical application; however, it is difficult to obtain and test experimental samples immediately following surgery. The aim of the present investigation is to elucidate the effect of storage conditions on the ability of preserved tissue samples to mimic freshly harvested tissue. Porcine small intestine was used as a model tissue for the experiments. The treatment conditions were freshly harvested, 24-h aged in phosphate-buffered saline at 5 degrees C and formalin-fixed tissue. Adhesive performance of cyanoacrylate and a newly synthesized tissue adhesive on the three substrates was characterized by T-peel testing. Regardless of the adhesive used, the fresh tissue samples had the weakest bond strength. The 1-day aged tissue produced a bond that was approximately twice as strong, and the formalin-fixed intestine substrate had intermediate bond strength. Comprehensive tissue characterization using attenuated total reflection infrared (ATR-IR) spectroscopy, captive-bubble contact angle, Raman spectroscopy, bulk tissue water content measurement and histology were employed. The results from the different characterization techniques show that storage of tissue samples causes interfacial and chemical changes, limiting their ability to mimic freshly harvested tissue. In particular, the results show the importance of water detected by ATR-IR in mediating adhesion to the tissue samples.