Investigation on the Behavior of κ -Carrageenan Hydrogels for Compressive Intra-Vessel Disintegration

Gel disintegration via compression is a possible approach for the reversal of the occlusion of male vasa deferentia (VD) by hydrogels. κ -carrageenan (KC) hydrogels can be used for such an application. To determine the required forces for in-vessel compressive disintegration, a gel-tube model, preparing KC gels in different tubes, is studied. These gels are of alternating biopolymer (1-3% by mass) and potassium (100-300 mM) concentration. Gel-filled tubes are uniaxially compressed at two different compression speeds (1 and 0.3 mm s^-1 ). Breakage compression strains are cross studied by shear breaking gel measurements using dynamic mechanical analysis. The measurements showed good agreement. Gel structure disintegration occurred below (62 ± 8) % strain. During compression, three stages of gel disintegration are present. Gel-tube wall detachment, gel rupture, and gel expulsion. The force required for gel disintegration and tube deformation can be added arithmetically. From the modulus of a human aortae model, it is estimated that average human pinch forces are insufficient to disintegrate 2% and 3% by mass KC hydrogels in VD by massage. The compressive disintegration would require a compression device while evading tissue damage.