Endoscopic Next Generation Tissue-Adhesive Tattoo (TAT2) Ink Delivery System
Biomedical Engineering
Chintan Shah
Abstract
Tissue marking, or tattooing, is used during endoscopic procedures to identify lesions for follow-up and surgical resection. However, existing tattoo inks diffuse extensively, reducing the accuracy of later localization. Tissue-Adhesive Tattoo, Generation 2 (TAT2) is a novel mucoadhesive ink that improves spot containment by more than 90% compared with current clinical inks. Although TAT2 enables multi-site marking in confined regions, conventional syringes provide limited control: small variations in hand pressure can produce markings that are too faint, too diffuse, or inconsistent. These challenges motivated the development of a syringe attachment that enhances tactile feedback, provides controlled volume delivery, and maintains compatibility with standard 10 mL syringes. Two designs were created – a screw-advance mechanism and a spring-plunger mechanism – and compared with an unmodified syringe. Six volunteers evaluated all three devices under three conditions: non-blind injections with a 27G needle, non-blind injections with a sclerotherapy catheter, and blind injections with the same catheter. Each volunteer delivered repeated 0.5 mL injections, and variance from the expected volume was measured. The spring-plunger device generated the most consistent injections, producing significantly reduced volume variance (p<0.0001). The screw-advance design improved precision over the conventional syringe (p<0.001) but remained less consistent than the spring-plunger (p<0.05). In ex vivo tests using porcine intestinal tissue to evaluate marking area, contrast, and injection time, the spring-plunger produced smaller and more contained markings (p<0.05), while conventional syringes generated broader spreads. Overall, these findings demonstrate that mechanical support with tactile feedback can substantially improve precision and reliability in endoscopic tattooing.