Utilization of embedded printing for fabrication of 3D complex-shaped microfluidic devices in hydrogels and silicone composites
Restricted (Penn State Only)
- Author:
- Alioglu, Mecit Altan
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 16, 2023
- Committee Members:
- Jing Du, Outside Unit & Field Member
Ibrahim Ozbolat, Chair & Dissertation Advisor
Todd Palmer, Major Field Member
Larry Cheng, Major Field Member
Francesco Costanzo, Major Field Member
Albert Segall, Program Head/Chair - Keywords:
- 3D Printing
Bioprinting
Cancer-on-a-chip
Embedded Printing
Microfluidics
Silicone composite
Photocrosslinkable silicone
Organ Model Printing - Abstract:
- The demand for fabrication of tissue and organ models is being driven by emerging requirements in biomedicine, drug screening, and organ transplantation. To fulfill this demand the field of bioprinting has emerged. Despite the fact that several approaches have been created, new ways are still required to produce the complicated geometries of vascular networks and materials that mimic natural tissues. Recently, embedded printing technique has been developed. By overcoming the limitations imposed by gravity, embedded printing enables the creation of complicated structures that would otherwise be impossible to produce with traditional layer-by-layer deposition from the bottom. Even though embedded printing has enormous potential it is still in its infancy and ample amount of research is going on to develop new materials and methods to advance its capabilities and increase its potential applications. Over the last two decades, microfluidic devices have rapidly emerged as revolutionary platforms for research and medicine. Various kinds of materials and fabrication strategies have been used to manufacture microfluidic devices; however, most of these strategies face challenges including complexity, time consumption, and cost in recreating delicate and intricate structural organizations. Herein, a silicone composite was developed and employed as a functional support bath in which a sacrificial ink was 3D printed using embedded printing, enabling freeform fabrication of complex-shaped microfluidic devices. Si-Co was a soft material that had high optical transparency and tunable mechanical properties and yield stress with self-recovering ability. Sacrificial ink filaments formed inside the Si-Co support bath were found to be stable and circular with a wide range of resolution reaching up to 50 µm in channel size. The strategy was exemplified by fabricating microfluidic devices for generation of stable microgels of various sizes. To confirm biocompatibility of Si-Co, induced-pluripotent stem cell-derived endothelial cells were lined up inside microfluidic channels to obtain vascular mimics. Additionally, proof-of-concept spheroid fabrication devices were generated. Overall, the presented strategy allows for facile, rapid, cost-effective, and high-resolution printing and presents potential for the development of microfluidic devices for various applications. After the development of first silicone composite for the use of embedded printing, we developed a novel, transparent, 3D printable, photocrosslinkable, and tunable silicone composite that can be utilized as a support bath or an extrudable ink for embedded printing. The proposed silicone composite can be tuned to achieve ideal rheological properties, such as optimal self-recovery and yield stress, for use in 3D printing. When used as a support bath, it facilitated the generation microfluidic devices with circular channels of diameter up to 30 µm. To demonstrate its utility, flow focusing microfluidic devices were fabricated for generation of Janus microrods, which can be easily modified for multitude of applications. When used as an extrudable ink, 3D printing of complex-shaped micro and macro constructs were achieved with integrated electronics, which greatly extends its potential applications towards developing complex flexible parts for soft robotics and prosthetics. Further, its biocompatibility was tested with multiple cell types to validate its applicability for medical and tissue engineering use. Altogether, this material offers a myriad of potential applications in material and medical fields by providing a facile approach to developing complicated 3D structures and interconnected channels that can lift microfluidics and soft-robotics research to the next level. Finally, we have developed a novel method of “intraembedded printing” as an improvement for embedded printing. Intraembedded printing is achieved by printing within printed constructs. By using this technique potential applications with embedded printing can be significantly expanded and intricate organ models or microfluidic devices can be fabricated in a facile and rapid manner. To demonstrate the capabilities of this method, a novel breast cancer model and a pancreas model was fabricated. Overall, intraembedded printing technique presents an enormous potential in the fields of tissue engineering and biomedical research and applications by offering a platform for fabrication of microfluidic devices, tissue and organ models.