Poster J18 - Evaluation of DLP and 2PP Lithography for Printing of Patterned Surfaces for Agar Molds

Thursday, October 24, 2024

2:45 PM – 3:45 PM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Nellymar Santiago-Rivera

Undergraduate Researcher
Florida State University/National High Magnetic Field Lab
Tallahassee, Florida, United States

Co-Author(s)

AS

Annie Scutte

Graduate Student
FAMU-FSU College of Engineering, United States
JK

Jaideep Katuri

Postdoc
Famu-FSU College of Engineering, United States
SO

Samuel Omeke

Undergraduate Student
FAMU-FSU College of Engineering, United States
ZM

Zachary Meeks

Undergraduate Student
FAMU-FSU College of Engineering, United States
Anya Tillman

Undergraduate Researcher
National High Magnetic Field Lab, United States
Izabela Kowalik

Undergraduate Student
FAMU-FSU College of Engineering, United States
Vivienne Zacher

Undergraduate Researcher
National High Magnetic Field Lab
Hollywood , Florida, United States
CS

Claretta Sullivan

Senior Scientist
United State Air Force Research Laboratory, United States

Primary Investigator(s)

JA

Jamel Ali

Assistant Professor
Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Florida, United States

Introduction: Digital light projection (DLP) and two photon lithography (2PP) enables small scale printing of surfaces structures to evaluate their effects on cellular self-assembly and organization. Here we explore the use of DLP and 2PP to create molds for agar to evaluate bacterial patterning. Specifically, for this project, we create three-dimensional stamp-like structures to template agar with varying surface stiffness, and evaluate the resultant printed patterns.

Materials and

Methods: The design for the prints was created using Formlabs 4B and UpNano 2PP printers. For prints created using the 4B DLP system, the parameters used for the print was 2cm length, 2cm width, and 0.2cm thick with the pattern size of 50 or 100μm length, and 50 or 100μm in height. The patterns consist of a series of cylinders or squares. These patterns would then be used on the agar. Agar was made at a 5% wt/vol by using 10mL of the media, 200μL of black ink, and 0.5g of agar. This mixture is then autoclaved for an hour in 120°C. Printed stamps were sterilized and then agar was cast on the models. Agar was then allowed to cool down to 70-80°C. The agar was then pipetted onto the stamp. Then, the agar is left to solidify in a 4°C environment overnight. Once solidified, the agar is peeled from the mold. Molds we then used to culture F. johnsoniae overnight.

Results, Conclusions, and Discussions: When designing the circles or cylinders, there was an issue with pertaining smooth-edged circles on the software used; therefore, .stl files has sharp edges. As for the squares, they were successfully designed on the software. Furthermore, the microfabricated stamps have restrictions on the lowest feature size for the patterns - 100μm length and height. For smaller dimensions, the print did not successfully form. In addition, for features around 100μm in size, significant defects were observed in prints, with the most inconsistent being the cylinders or circles. These had printing errors in some areas as well as not steadily angled lines across the entirety of the structure. On the other hand, for the squares, the accuracy was more consistent, with some printing errors throughout the structure. The distance between the lines was also inconsistent throughout structure. As for the transfer of patterns onto agar stamps, the 5% agar appeared to fully obtain the pattern of the stamp, including the flaws. We noticed occasional bubbles formed when pouring, however the overall pattern was not significantly affected. The Formlabs printing quality seems to be inefficient when creating such accurate and small-scale structures. With the distances being inconsistent throughout each line, lines not pertaining their smoothness, and printing errors in certain areas. As a result, looking forward, we will use 2PP for higher resolution patterns. In addition, given that the translation of the pattern into the 5% agar was successful, attempting different concentrations of agar is the goal for the upcoming future. By manipulating the surface on which cell can grow, we can further develop an understanding on cell organization and qualities.

Acknowledgements (Optional): This work was funded by the National Science Foundation (EES-2000202, EES-2306449, CMMI-2000330 and EES-2219558) and supported by the NSF FAMU CREST Center award (EES-1735968). All the work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida. This work was funded and supported by the United States Air Force Research Laboratory though the MLR-CP program.