New Adhesive Hydrogel Splint to Correct Malacic Trachea (Tracheomalacia)

Tracheomalacia (TM) is an illness in which the tracheal cartilage is too soft to ensure the mechanical support of the airways.¹ This results in an excessive and potentially lethal collapse and narrowing of the airways. Current treatment techniques including, tracheal reconstruction, tracheoplasty, endoluminal, and extraluminal stents, however, come with certain limitations.^2-4<br/>We will present a new and simple approach to correct TM where a (malacic) Trachea can be supported extraluminally by the adhesive hydrogel splint (patch). To this end, a new hydrogel formulation has been synthesized. We found that these hydrogel patches provide profound wet adhesion on the tracheal surface, thanks to a two-step photo-polymerization approach that help to anchor the surface much better than previously known adhesive hydrogels. A finite element model of a rabbit trachea was also developed to investigate the deformation and stress responses under maximum negative pressure with and without wrapping an adhesive hydrogel patch to it.<br/>The numerical studies revealed that the hydrogel patch has the potential to preserve a more physiological shape of the trachea by constraining the membrane folding. Therefore, to validate the numerical model, and examine the potential use of the adhesive hydrogel, µ-CT and <i>ex vivo</i> experiments were also executed, respectively. To this end, few cartilage rings were removed from a healthy trachea to mimic the TM condition before executing these experiments in absence and presence of a hydrogel patch. At last, we could prove the hypothesis that airway collapse can be restrained by fixing the adhesive hydrogel splints superficially to a malacic trachea.<br/>Interestingly, hydrogels developed herein also displayed outstanding wet adhesion on the surface of other soft tissues (skin, liver, heart, kidney, and lung), and inorganic surfaces (glass, wood, plastic, and ceramic <i>etc.</i>).<br/><br/><br/><b>References:</b><br/><br/>A. Kamran, R. W. Jennings, <i>Front. Pediatr.</i> <b>7</b>, 1–9 (2019).<br/>J. S. Choi, J. Seok, M. R. Eom, E. Jung, S. A. Park, S. M. Joo, Y. J. Jun, K. W. Son, S. K. Kwon, <i>Clin. Exp. Otorhinolaryngol.</i> <b>14</b>, 328–337 (2021).<br/>C. Serrano-Casorran, S. Lopez-Minguez, S. Rodriguez-Zapater, C. Bonastre, J. A. Guirola, M. A. De Gregorio. <i>Pediatr. Pulmonol.</i> <b>55</b>, 1757–1764 (2020).<br/>F. Gorostidi, C. Courbon, M. Burki, A. Reinhard, K. Sandu, <i>Laryngoscope</i>. <b>128</b>, E53–E58 (2018).