Correlations between rheological and mechanical properties of fructo-polysaccharides extracted from Ornithogalum billardieri as biobased adhesive for biomedical applications.

Polysaccharides are extracted from Ornithogalum by maceration using different ultrasound (US) treatment times (0%US, 50%US, 100%US), and under optimized extraction conditions (OP%US). The total carbohydrates content (TCC) and proteins content of the extracts were determined. Data show that the extraction parameters significantly influence the extracts composition. Rheological measurements allowed determining the liquid, intermediate and gel states of the extract's solutions. The adhesion strength of the solutions was evaluated on paper and polylactide (PLA) substrates to evaluate their potential as environmentally friendly adhesive. OP%US presents the highest adhesion strength (1418.3 kPa) on paper, and is further tested on pork skin substrates. The adhesion strength is higher on skin/paper (870 kPa) than on skin/skin (411 kPa) substrate due to the capillary force of paper which allows penetration of adhesive into the micropores of paper. The correlation between rheological properties and adhesion strength indicates that the adhesion strength strongly depends on the state of adhesives and the substrate type. SEM analyses show that higher adhesion strength (intermediate and gel states) involves both cohesive and adhesive failure, whereas only adhesive failure is observed in liquid state on PLA substrates. Therefore, these polysaccharides extracts could be very promising as tissue adhesive in medical applications.