Recent Advances - Paige Liu

Overview

Two of the factors driving innovation in 3D printing for microfluidics are channel size and resolution,¹.

Exploration into additive materials using other materials such as concrete and biomaterials has also been of interest².

There are also some new methods of 3D printing that are being developed.

High Resolution 3D Printing Using a Customized Resin and Photolithography Printer

Using an adapted stereolithography (SLA) printer and a series of custom-formulated resins, a lab was able to create microchannels at up to 18x20 um resolution³. This method has not been reproduced in literature and definitely has yet to be scaled up, but it holds promise for the future of 3D printing microfluidic circuits.

(Will include some figures of the channel dimensions for scale from the paper)

Additive Manufacturing of Biomaterials

Additive manufacturing using biomaterials is a hot topic due to the obvious impact it would have on the development and manufacture of medical devices such as stents, artificial joints, etc. One of the driving forces of advancing additive manufacturing techniques for the production of biomedical devices is to reduce manufacturing costs and allow for rapid prototyping capabilities with less waste. The high variances in geometry from biological system to biological system (e.g. person to person) creates further demand for 3D printing type technologies, as the designs are easily customized in contrast to traditional manufacturing techniques.

One of the main challenges that come from adapting AM to biomaterials is removing powder/ other support type materials from the final product. Generally, any loose material could be problematic in-vitro since there could be problems with biocompatibility in a scattered vs. a conhesive final product⁴. Other challenges include high initial costs on the research and development side.

Computed Axial Lithography (CAL)

(Some technical details) (A cool video) (Go Bears)

Volumetrically photopolymerized structures as opposed to traditional layer-by-layer deposition methods⁵.

References

¹Au, A. K., Huynh, W., Horowitz, L. F. & Folch, A. 3D-Printed Microfluidics. Angew. Chemie - Int. Ed. 55, 3862–3881 (2016). DOI: 10.1002/anie.201504382

²Ngo, T. D., Kashani, A., Imbalzano, G., Nguyen, K. T. Q. & Hui, D. Additive manufacturing (3D printing): A review of materials, methods, applications and challenges. Compos. Part B Eng. 143, 172–196 (2018). DOI: 10.1016/j.compositesb.2018.02.012

³Gong, H., Bickham, B. P., Woolley, A. T. & Nordin, G. P. Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels. Lab Chip 17, 2899–2909 (2017). DOI: 10.1039/C7LC00644F

⁴Bose, S., Ke, D., Sahasrabudhe, H. & Bandyopadhyay, A. Additive manufacturing of biomaterials. Prog. Mater. Sci. 93, 45–111 (2018). DOI: 10.1016/j.pmatsci.2017.08.003

⁵Kelly, B. E. et al. Volumetric additive maufacturing via tomographic reconstruction. Science (80-. ). 126, 21 (2019). DOI: 10.1126/science.aau7114