Laser Ablated Microstructures on Different Biocompatible Materials for Various Downstream Applications

Abstract

CO2 laser processing has been explored as an alternative high-throughput and cost-effective method for rapid microfabrication of lab-on-chip devices Laser ablation works by applying high-energy pulses of focused laser light to remove targeted sections of a substrate material by vaporization chipping or other erosive processes Protocols have been developed to provide a streamlined methodology for the fabrication of various materials for a wide range of biological applications in many studies However there are still no comprehensive and systematic studies in diverse materials and applications Our work is validating existing results as a study with the complete context and integration 　　In our study we demonstrate CO2 laser ablation on different biocompatible materials including borosilicate glass polydimethylsiloxane (PDMS) polymethylmethacrylate (PMMA) and polystyrene (PS) for various downstream applications Based on CO2 laser ablation for microfabrication glass apertures were created for cell trapping and ablated PMMA and PDMS molding was demonstrated for the rapid prototyping of biodegradable polyvinyl alcohol/polyvinylpyrrolidone (PVP/PVA) microneedle arrays Finally in PS which is a conventional substrate of culture devices concave microwells and through holes were obtained for three-dimensional cell culture Microwells and hanging drops are two different multicellular cancer aggregate (MCA) cultivation techniques based on different principles for 3D culture: ultra-low-attachment culture systems with physical boundaries and scaffold-free hanging-drop-only interactions by gravity respectively 　　We created glass apertures by CO2 laser ablation for single-cell trapping and validated by in situ fluorescent staining that the isolated cells retained viability PDMS showed good surface smooth-ness around the concave microwells after CO2 laser processing and better than PMMA for fabricating a sufficient-strength microneedle with a suitable aspect ratio Microneedle arrays fabricated by both PDMS or PMMA showed good ability for encapsulating high-molecular-weight (MW) particle fluorescence markers (155 kDa MW for FITC-dextran) and good insertion ability for penetrating porcine skin as verified by staining with blue tissue marking dye Microwells and hanging drops used as 3D culture platforms were found to form MCAs with good cell viability The microwells whose sizes were controllable by setting the CO2 laser energy were capable of culturing consistent and homogeneous MCAs sized approximately 90 to 140 μm and served as a physical boundary to constrain MCA growth Finally drug screening with anticancer drugs such as doxorubin (DOX) was successfully performed within the hanging drop array Here we present comprehensive insights into CO2 laser ablation for various biological applications

Date of Award	2019
Original language	English
Supervisor	Ting-Yuan Tu (Supervisor)