On the Characterization of Novel Step-Index Biocompatible and Biodegradable poly(D,L-lactic acid) Based Optical Fiber

Abstract

We report on the first step-index biodegradable polymer optical fiber (bioPOF) fabricated using commercially available polyesters, with a core made from poly(D,L-lactic-co-glycolic acid) and a cladding made from poly(D,L-lactic acid). We prepared the preforms with a rod-in-tube technique and the fibers with a standard heat drawing process. We discuss the chemical and optical properties of the polyesters along the fabrication process from polymer granulates to optical fiber. More specifically, we address the influence of the processing steps on the molecular weight and thermal properties of the polymers. Cutback measurements return an attenuation of 0.26 dB/cm at 950 nm for fibers with an outer diameter of 1000 ± 50 µm, a core of 570 ± 30 µm, and a numerical aperture of 0.163. When immersed in phosphate-buffered saline (PBS), bioPOFs degrade over a period of 3 months, concurrent with a 91% molecular weight loss. The core decomposes already after three weeks and features 85% molecular weight loss. There is no any additional optical loss caused by immersion in PBS during the first 30-40 min for a bioPOFs with a diameter of about 500 µm. Our result demonstrates that bioPOF can be suitable for

Lighting the Path: Light Delivery Strategies to Activate Photoresponsive Biomaterials In Vivo

“…Although complete degradation may take months, it is important to recognize that light attenuation in degradable polyester waveguides such as PDLLA can increase dramatically (>1 dB cm −1 ) within an hour of immersion. [185] Citrate-based elastomers are degradable alternatives to silicones, offering high transparency, widely tunable stiffnesses (<1 kPa to MPa) and degradation rates (days to years), and well-established biocompatibility. [186] Shan et al [133] developed a step-index optical fiber from two biocompatible citratebased elastomers for organ-scale light delivery and detection.…”

“…As described earlier, the tendency of PLLA to crystallize, which would cause unwanted scattering, was suppressed in this case by rapid cooling during the fiber drawing process, but can also be avoided by using intrinsically amorphous polyesters, many of which are clinically approved for in vivo use [ 184 ] and can be processed into waveguides at much lower temperatures. [ 185 ] Recently, our workgroup reported a series of amorphous polyester waveguides produced from PDLLA, PLGA, and PLA‐ co ‐PCL (PCL = polycaprolactone) using simple extrusion printing at <100 °C and moderate pressures (20–600 kPa). [ 121 ] The polymers have T g around body temperature, and waveguides were therefore soft and flexible under near‐physiological conditions.…”

Challenges in the Fabrication of Biodegradable and Implantable Optical Fibers for Biomedical Applications

“…We also evaluated the optical loss at 633 nm of these unclad PDLLA fibers during immersion in physiological fluid, phosphate-buffered saline (PBS) at 37 °C and pH = 7.4, confirming that PDLLA-based fibers can efficiently deliver light over a period of 30 min, which is commensurate with that required for photodynamic therapy (PDT). In subsequent work, we also reported on the fabrication of SI polyester-based fibers, in which the core consisted of poly(D,L-lactic-co-glycolic acid) (PDLLA) and the cladding of poly(D,L-lactic acid) (PDLLA) [ 56 ]. The preforms were prepared by means of a rod-in-tube technique by melting granulates, and the core-cladding fibers were manufactured with a standard heat drawing process.…”

Cleaving of PMMA Microstructured Polymer Optical Fibers with 3- and 4-Ring Hexagonal Cladding Structures

“…In the last few years, polymer optical fibers (POFs) have been demonstrated as a realistic alternative to silica optical fiber (SOF) in many application fields, driven by the excellent mechanical and optical properties of the polymers. Most of the POFs in the market are composed of polymethylmethacrylate (PMMA), a material with significant interest due to its flexibility, easy handling and low cost, or other specific characteristics such as its low Young’s modulus, high thermo-optic coefficient, biological compatibility [ 1 ] and electromagnetic immunity, among others [ 2 ]. These advantages are interesting in general applications but still more in sensing applications, especially the Young’s modulus, in which large deformation can be applied without breaking the optical fiber [ 3 ], and the thermo-optic coefficient [ 4 ], which allows one to modulate the sensor response with the temperature, among other novelty applications [ 5 ].…”