Objectives: Duodenal mucosal resurfacing (DMR) is a surgical method to treat type 2 diabetic mellitus. The current study developed laser-assisted photothermal DMR to ablate the duodenal mucosal surface in an instant and selective, compared with conventional DMR methods. Methods: A 1470 nm wavelength was selected for the current study because of its high optical absorption coefficient in intestine tissue. A radial optical fiber was designed for concentric irradiation to the duodenal mucosal surface. Ex vivo liver tests were performed to evaluate various irradiation energy (25–400 J). Both numerical simulations and an ex vivo duodenum tests were conducted to confirm the thermal response of the duodenum to the laser irradiation. In vivo experiments were performed to evaluate the depth of the ablated duodenal mucosa after the treatment. Result: The extent of the coagulation area in ex vivo liver tissue after laser irradiation increased with the energy delivery. Numerical simulations and ex vivo duodenum experiments showed a concentric temperature distribution in the duodenum wall. The histological assessment following in vivo experiments revealed that the 10 W for 15 s condition ablated the duodenal mucosal layer in the cross-sectional direction by more than 50%, compared to the control. Conclusion: 1470 nm laser light with concentric radial irradiation under 10 W for 15 s ablated the sufficient depth of the duodenal mucosal layer. Further in vivo studies will be performed to confirm the efficacy of the photothermal DMR. Significance: The current study demonstrated the feasibility of a novel photothermal ablation for DMR.

The current study aims to evaluate the efficacy and safety of photothermal duodenal mucosal ablation (PDMA), utilizing a 1470 nm wavelength and a diffusing fiber (DF), in ex vivo liver tissues and an in vivo type 2 diabetes mellitus (T2DM) rat model. The 1470 nm laser with the DF was used for uniform duodenal mucosal ablation. After optimizing dosimetry (9–49 J) ex vivo, PDMA was performed on twelve T2DM rats (n = 4 per group) induced by a high-fat diet and streptozotocin. Glycemic metabolism and histological changes were monitored for 14 days. All experimental data were analyzed using the Mann–Whitney U test for statistical significance. Optimized PDMA (5 W for 5 s) achieved uniform, circumferential mucosal ablation while preserving outer layers. Histology assessment confirmed optimal ablation at day 2 with substantial regeneration by day 14. Consequently, the PDMA group showed significantly improved glycemic indexes at day 14 compared to the sham control. Therefore, the proposed PDMA may be promising in remodeling the duodenal mucosa for glycemic control in T2DM. Future research will evaluate the PDMA in a larger number of animals to warrant efficacy and safety for clinical translation.

Optical fibers have emerged as a promising approach for minimally invasive biomedical applications. The fiber tips are modified to deliver the laser energy to targeted areas. The modified fiber tip is covered by a glass cap to prevent laser–tissue interactions, debris redeposition, and thermal loading. However, the influence of the glass cap on the output laser beam distribution from the fiber tip has not been thoroughly studied to optimize ablation efficacy. Therefore, this study evaluated the effect of the glass cap geometry on the high-power emission of the 76° radial optical fiber (ROF) tip for laser ablation (LA) of Barrett’s Esophagus (BE). The glass cap was modified on the outer surface by CO2 cutting system. 1470 nm at 20 W was applied to evaluate the ablated areas (i.e., ablation width and depth). A medical balloon was used for centering the ROF within esophagus. Ex vivo porcine liver experiments were used to compare the ablated area of the modified/normal glass cap-sealed ROFs (MRF and NRF, respectively). Ex vivo and in vivo porcine esophagus experiments were tested to validate the performance of the balloon-integrated MRF (BMRF) with the 1470 nm for BE treatment. The MRF showed a wider ablation width, a shallower ablation depth than the NRF under the same laser conditions. Moreover, the MRF could reduce the number of repositioning to minimize overlapping ablation compared with NRF. The current findings showed the feasibility of the BMRF device with 1470 nm laser for BE treatment (i.e., approximately 300–400 µm ablation depth and 6 mm ablation width in mucosal layer). Further in vivo models with various esophagus sizes will be conducted to warrant the efficacy of the BMRF device with 1470 nm for LA of BE.