Scalable production of 3D microtissues using novel microfluidic technologies

Tissue engineering approaches are widely studied with the goal to replace or repair human tissues. However, while studies are often promising in a laboratory environment, there remain difficulties in the translation of laboratory-based studies towards clinical applications due to low in vivo efficiency and/or complex impractical procedures.An interesting strategy for improving therapy effectiveness is by evolving from conventional 2D cell culture to more biomimetic 3D cell culture approaches. While therapy efficiency can be greatly improved using 3D cell culture, current 3D microtissue production techniques are often non-scalable batch processes, limiting clinical and industrial translation. A continuous production method is needed in order to improve the microtissue production rate and improve the feasibility of clinical application.
Microfluidics offers the possibility to evolve microtissue production towards a continuous process. Using conventional on-chip microfluidics, microtissues can be produced in a controlled and continuous manner by cell encapsulation in hollow microcapsules. However, conventional on-chip microfluidics offers challenges such as complex multistep processes, the use of potentially harmful oils and surfactants and often low throughputs, which are currently hampering widespread clinical and industrial translation of microfluidically produced microtissues. There is therefore a need to evolve microfluidics towards a clean, fast and single step scalable approach to fulfill the clinical requirements for tissue engineering approaches that take advantage of 3D microtissues.
This thesis describes multiple microfluidic solutions that focus on overcoming these challenges hampering the widespread clinical and industrial use of microtissues. A reusable, cleanroom-free, multifunctional microfluidic device is developed using standard cutting and abrasion technology, which allows the production of microtissue-laden microcapsules in a single step-manner. This on-chip process is then evolved towards an off-chip jetting approach which allows for the production of microtissue-laden microcapsules in an ultra-high throughput manner (>10 ml/min) without the need of potentially harmful oils and surfactants. This in-air microfluidic approach is also utilized for mass production of microtissues in larger compartmentalized hydrogels, which are used for the production of large clinical-sized tissues. A multitude of microtissues are formed using these described microfluidic technologies such as human mesenchymal stem cell spheroids, chondrocyte spheroids, fibroblast spheroids, cholangiocyte and cholangiocarcinoma organoids, lumen-forming embryoid bodies, contracting cardiospheres, and clinical sized cartilage tissues.
To summarize, this thesis introduces multiple microfluidic systems for scalable microcapsule and microtissue production with the aim to remove the hurdles towards clinical and industrial translation of 3D microtissues.