Self-Expandable Electrode Based on Chemically Polished Nickel-Titanium Alloy Wire for Treating Endoluminal Tumors Using Bipolar Irreversible Electroporation

Photo-responsive self-expanding catheter with photosensitizer-integrated silicone-covered membrane for minimally invasive local therapy in malignant esophageal cancer

Photodynamic therapy (PDT) using photosensitizer (PS)-integrated covered self-expandable metallic stents (SEMS) is proposed a new therapeutic approach for the treatment of palliative malignancies; however, the currently hydrophobic PS reduces the photoreactive effect, which leads to aggregation with low water solubility. In here, an aluminum (III)-phthalocyanine chloride tetrasulfonic acid (Al-PcS4)-integrated silicone-covered self-expanding catheter was successfully fabricated to perform localized PDT. The ratio of MeOH and Al-PcS4 concentrations was optimized to achieve PS coating uniformity. The photodynamic activity of the Al-PcS4-integrated silicone membrane was evaluated through laser exposure on membrane-layered tumor cell lines, tumor xenograft-bearing mice. PDT with the Al-PcS4-integrated membrane successfully generated sufficient cytotoxic singlet oxygen, inducing cell death in the esophageal cancer cell lines. PDT-treated tumor xenograft-bearing mice undergo apoptotic cell death and showed significant tumor regression. Localized PDT using an Al-PcS4-integrated silicone-covered self-expanding catheter was technically successful in the rabbit esophagus without severe complications. Based on the endoscopy, esophagography, histology, and immunohistochemistry, our study verified that localized PDT using the Al-PcS4-integrated silicone-covered self-expanding catheter was effective and safe to evenly induce tissue damage. Al-PcS4-integrated silicone-covered self-expanding catheter has substantial potential for the minimally invasive local therapy in malignant esophageal cancer.

Ti-Based Metallic Biomaterials for Antitumor Applications

Titanium (Ti)-based metallic biomaterials (MBs) are traditionally employed as mechanical supports and constraints in clinical practice, owing to their superb comprehensive mechanical properties, great corrosion resistance, and good biocompatibility. Recently, Ti-based MBs have emerged as promising candidates for antitumor applications. These developments focus on the functionalization of Ti-based MBs to inhibit tumor propagation and recurrence. This work systematically examines the antitumor approaches of Ti-based MBs and categorizes them into physical and chemical approaches. Physical strategies, such as the photothermal and photocatalytic techniques, are usually related to material-specific properties. Chemical approaches often employ controlled local drug delivery (LDD) systems. Ti-based LDD systems enable the targeted release of chemotherapeutics, metal ions, or immunomodulatory agents at tumor sites. This review highlights the efficacy of these surface-functionalized Ti-based MBs against diverse tumors. Additionally, the challenges and prospects of antitumor Ti-based MBs are also discussed.

Effects of bipolar irreversible electroporation with different pulse durations in a prostate cancer mouse model

Irreversible electroporation (IRE) is a non-thermal ablation technique for local tumor treatment known to be influenced by pulse duration and voltage settings, affecting its efficacy. This study aims to investigate the effects of bipolar IRE with different pulse durations in a prostate cancer mouse model. The therapeutic effectiveness was assessed with in vitro cell experiments, in vivo tumor volume changes with magnetic resonance imaging, and gross and histological analysis in a mouse model. The tumor volume continuously decreased over time in all IRE-treated groups. The tumor volume changes, necroptosis (%), necrosis (%), the degree of TUNEL-positive cell expression, and ROS1-positive cell (%) in the long pulse duration-treated groups (300 μs) were significantly increased compared to the short pulse duration-treated groups (100 μs) (all p < 0.001). The bipolar IRE with a relatively long pulse duration at the same voltage significantly increased IRE-induced cell death in a prostate cancer mouse model.

Localized Photodynamic Therapy Using a Chlorin e6-Embedded Silicone-Covered Self-Expandable Metallic Stent as a Palliative Treatment for Malignant Esophageal Strictures

Localized photodynamic therapy (PDT) uses a polymeric-photosensitizer (PS)-embedded, covered self-expandable metallic stent (SEMS). PDT is minimally invasive and a noteworthy potential alternative for treating esophageal strictures, where surgery is not a viable option. However, preclinical evidence is insufficient, and optimized irradiation energy dose ranges for localized PDT are unclear. Herein, we validated the irradiation energy doses of the SEMS (embedded in a PS using chlorin e6 [Ce6] and covered in silicone) and PDT-induced tissue changes in a rat esophagus. Cytotoxicity and phototoxicity in the Ce6-embedded SEMS piece with laser irradiation were significantly higher than that of the silicone-covered SEMS with or without laser and the Ce6-embedded silicone-covered SEMS without laser groups (all p < 0.001). Moreover, surface morphology, atomic changes, and homogeneous coverage of the Ce6-embedded silicone-covered membrane were confirmed. The ablation range of the porcine liver was proportionally increased with the irradiation dose (all p < 0.001). The ablation region was identified at different irradiation energy doses of 50, 100, 200, and 400 J/cm2. The in vivo study in the rat esophagus comprised a control group and 100, 200, and 400 J/cm2 energy-dose groups. Finally, histology and immunohistochemistry (TUNEL and Ki67) confirmed that the optimized Ce6-embedded silicone-covered SEMS with selected irradiation energy doses (200 and 400 J/cm2) effectively damaged the esophageal tissue without ductal perforation. The polymeric PS-embedded silicone-covered SEMS can be easily placed via a minimally invasive approach and represents a promising new approach for the palliative treatment of malignant esophageal strictures.