Flexible biodegradable citrate-based polymeric step-index optical fiber.

Implanting fiber optical waveguides into tissue or organs for light delivery and collection is among the most effective ways to overcome the issue of tissue turbidity, a long-standing obstacle for biomedical optical technologies. Here, we report a citrate-based material platform with engineerable opto-mechano-biological properties and demonstrate a new type of biodegradable, biocompatible, and low-loss step-index optical fiber for organ-scale light delivery and collection. By leveraging the rich designability and processibility of citrate-based biodegradable polymers, two exemplary biodegradable elastomers with a fine refractive index difference and yet matched mechanical properties and biodegradation profiles were developed. Furthermore, we developed a two-step fabrication method to fabricate flexible and low-loss (0.4 db/cm) optical fibers, and performed systematic characterizations to study optical, spectroscopic, mechanical, and biodegradable properties. In addition, we demonstrated the proof of concept of image transmission through the citrate-based polymeric optical fibers and conducted in vivo deep tissue light delivery and fluorescence sensing in a Sprague-Dawley (SD) rat, laying the groundwork for realizing future implantable devices for long-term implantation where deep-tissue light delivery, sensing and imaging are desired, such as cell, tissue, and scaffold imaging in regenerative medicine and in vivo optogenetic stimulation.

Augmentation of N-butyl cyanoacrylate embolization of cranial, head, and neck tumors by simultaneous infusion of 5% dextrose solution.

BACKGROUND: N-Butyl cyanoacrylate (NBCA) is an adhesive liquid embolic agent widely used for embolization of cranial, head and neck tumors. Adequate distal penetration of NBCA into vessels with the smallest possible diameter, while preventing its reflux, is still a challenge, even in experienced hands. Simultaneous infusion of 5% dextrose in water solution (D5W) through the guiding catheter has been described before as a technique for improving embolization of dural arteriovenous malformations. OBJECTIVE: To describe our experience with a modified D5W guide catheter push technique during embolization of hemorrhagic cranial, head and neck tumors. The embolization technique and pitfalls which might lead to complications are discussed in detail. MATERIALS: A retrospective series of 20 patients treated with the D5W push technique during embolization of cranial, head and neck lesions between 2007 and 2013 is presented. The goal of embolization was preoperative or palliative embolization of hemorrhagic tumors. Localization and histopathologic diagnosis of lesions, concentration of NBCA used, subsequent surgical treatment, intraoperative blood loss, and complications were evaluated. RESULTS: A total of 44 arterial pedicles were embolized during 22 treatment sessions. Adequate embolization of the lesions was achieved in all cases. Transient ischemic attack due to atheroma embolization (from the aorta) was seen in one patient (4%). Persistent vascularity of tumor associated with minimal intraoperative bleeding was reported in one patient (4%). Recurrence of epistaxis was reported in two patients diagnosed with Osler-Weber-Rendu syndrome. CONCLUSIONS: The D5W push technique during NBCA embolization of cranial, head and neck tumors is a safe and effective method to enhance penetration of the embolizing agent.