Adhesive Cements That Bond Soft Tissue Ex Vivo

Current tissue adhesives face limitations in bonding to soft tissues. Cyanoacrylates offer high strength but lack flexibility. Fibrin glue provides flexibility but weaker bonding. No prior work had resolved the challenge of creating a stiff ceramic adhesive that also bonds effectively to soft tissues. This gap motivated the development of phosphoserine modified cements (PMCs). Prior research has shown that amino acid content influences adhesion in calcified tissues. However, the effect of amino acid ratios on soft tissue bonding remained unclear. This paper introduces a new approach to tissue adhesion by modifying cement with phosphoserine. The study addresses a specific need in surgical applications where both hard and soft tissue adhesion is required. The novelty lies in the combination of ceramic properties with biomimetic bonding capabilities.

The study aimed to assess the soft tissue bonding potential of a new phosphoserine modified cement (PMC). The specific problem addressed is the lack of adhesives that can bond strongly to soft tissues while maintaining ceramic-like stiffness. The motivation stems from surgical needs where adhesion between hard and soft tissues is critical. The researchers tested two PMC formulations: calcium metasilicate (CS1) and alpha tricalcium phosphate (αTCP). The goal was to determine optimal phosphoserine ratios for maximum adhesion. The study also compared PMC performance to existing adhesives like cyanoacrylate and fibrin glue. By evaluating lap shear strength (LSS), the team sought to identify the most effective PMC composition. The findings could lead to improved surgical adhesives for complex tissue interfaces.

The study used lap shear strength (LSS) testing on porcine skin to evaluate bonding performance. Two phosphoserine modified cements (PMCs) were tested: calcium metasilicate (CS1) and alpha tricalcium phosphate (αTCP). Curing times of 0.5, 1.5, and 4 hours were assessed for each material. The researchers varied phosphoserine mole ratios from 30-90% to determine optimal bonding. Wet milling was applied to αTCP particles to assess size effects on adhesion. Cyanoacrylate and fibrin glue served as control adhesives for comparison. LSS values were measured using standardized mechanical testing protocols. The results were analyzed to identify trends in bond strength across different formulations and conditions.

CS1 PMCs achieved peak LSS values of 84, 132, and 154 kPa after 0.5, 1.5, and 4 hours of curing, respectively. Cyanoacrylate reached 207 kPa, while fibrin glue achieved only 33 kPa. αTCP PMCs reached a final LSS of approximately 110 kPa. The strongest αTCP bonding occurred at amino acid contents of 70-90 mol%, contrasting with prior findings in calcified tissues. Wet milling improved αTCP adhesion by reducing particle size. For CS1 PMCs, optimal bonding was observed at 30-50% phosphoserine. PM-CPCs exhibited ceramic-like stiffness after setting. These results suggest PMCs can bond effectively to soft tissues while maintaining structural rigidity.

The study found that phosphoserine modified cements (PMCs) can bond effectively to soft tissues. CS1 PMCs showed increasing strength with longer curing times. αTCP PMCs achieved the highest LSS at 110 kPa. The optimal amino acid content for αTCP was 70-90 mol%, differing from calcified tissue studies. Wet milling improved αTCP bonding by reducing particle size. CS1 PMCs performed best at 30-50% phosphoserine. PM-CPCs maintain ceramic-like stiffness after setting. These findings suggest PMCs warrant further investigation as tissue adhesives, particularly at hard-soft tissue interfaces.