Two new preprints!

The Pompano lab has been busy at the start of 2024! Check out our two new preprints on BioRxiv:

Ozulumba et al

One on biomaterials for immune cell photo-patterning:

Mitigating reactive oxygen species production and increasing gel porosity improves lymphocyte motility and fibroblast spreading in photocrosslinked gelatin-thiol hydrogels

by Tochukwu Ozulumba et al

And one on a bioanalytical method to map out oxygen consumption and hypoxia in live tissue explants:

Spatially resolved quantification of oxygen consumption rate in ex vivo lymph node slices

by Parastoo Anbaei et al

Anbaei et al

We welcome feedback on these manuscripts and look forward to sharing the revised versions again after peer review!

First paper of 2023! Easy fab bubble traps

Congrats to Hannah Musgrove, Amirus (Ovi) Saleheen, and Jon Zatorski on their latest paper, now published in Micromachines as part of the Womens Special Issue! To address the perennial problem of bubbles arising in the tubing of microfluidic cultures and organs-on-chip, they adapted a previously described, passive bubble trap design for fabrication by 3Dprinting or by high-throughput machining. These two fabrication methods enable reproducible, low-cost fabrication at moderate or large throughput, respectively. We share the design files in the linked Dataverse site, so feel free to try them out!

New paper: Photopatterned 3D cultures in a chip

We are delighted that Jennifer Ortiz-Cardenas’s thesis work is now published in Organs-on-a-chip! Jenn established a method to micropattern cell-laden 3D cultures on a microfluidic chip, with resolution as good as 100-micron. She established everything from how to design and fabricate the PDMS chamber to avoid catching bubbles or patterning microcracks in the gel, to choosing what light source would provide the required wavelength, intensity, and columnation, to rigorously comparing the properties of two types of biomaterials in terms of patterning, and carefully establishing the capabilities and limitations of biocompatibility of this system with primary lymphocytes. Read the paper here! https://www.sciencedirect.com/science/article/pii/S2666102022000040

New paper: Magnetic impeller pump for organs-on-chip

Congratulations to Sophie Cook and co-author Hannah Musgrove for their paper now available online before print in Lab on a Chip! Sophie invented a creative impeller pump design for in-line recirculaton of media through on-chip cultures and organs-on-chip. The pump does not require any tubing or external pumps, just a magnetic stirring platform that easily fits in the incubator without heating it up. This was an exciting collaboration with Prof. Amy Throckmorton of Drexel University, who conducted advanced fluid dynamic simulations to better understand and predict the fluid flow around the pump and how it controlled flow through the channels.

This pump lays the groundwork for recirculating flow control in long-term cultures and multi-tissue cultures. Sophie and Hannah showed that it was mechanically compatible with recirculating of lymphocytes, and when 3D printed in the right resin, could be used to circulate model lymphocytes overnight.

New paper: Fluorination of 3D printed chips

Megan Catterton’s latest paper is out in Langmuir! We report a protocol for fluorosilanization of SLA or DLP 3D printed chips, to give them a Teflon-like surface. Fluorination of 3D printed microfluidic chips was challenging before, but thanks to Megan’s work, it is now straightforward. Her method provides easy access to patterned hydrophobicity on the surface of the chip, and to two-phase droplet microfluidics.

Catterton M, Montalbine AN (#), & Pompano RR. “Selective Fluorination of the Surface of Polymeric Materials After Stereolithography 3D Printing.” Langmuir (2021). Accepted. [Publisher link]

New review: Modeling immunity in vitro

Our first collaborative review article, written with Prof. Jennifer Munson and Jenn Hammel of Virginia Tech teamed up with Pompano Lab students Sophie Cook and Maura Belanger, is out in Annual Reviews of Biomedical Engineering!

We cover models of immune organs (lymph node, bone marrow, spleen, lymphatics, etc) and models of peripheral organs that feature immunity.

For each organ, we systematically review models based on

(i) tissue slices

(ii) microfluidics and organs-on-chip

(iii) engineered models, e.g. 3D cultures

The focus is primarily on models of healthy tissue, though with some discussion of models of inflammatory disease as well. Enjoy!

JH Hammel’, SR Cook’, MC Belanger’, JM Munson, and RR Pompano. “Modeling Immunity In Vitro: Slices, Chips, and Engineered Tissues.” Annual Review of Biomedical Eng, 2021, online ahead of print. [pubmed] ‘Equal contributions.

Prof. Pompano contributes to article on active learning in remote courses

Prof. Pompano co-authored a paper with Prof. and Chair Jill Venton on how active learning helps engage students during remote courses. The article includes many tips and lessons learned from Prof. Pompano’s Analytical courses, which were offered remotely in 2020 due to the COVID-19 pandemic.

The article is part of a series organized by Analytical Bioanalytical Chemistry on teaching during the pandemic. We hope that it is helpful!

Two new papers on lymph node slices

Two papers were published from our lab in late 2020 and early 2021, establishing the methods and possibilities of using murine lymph node slices to study short-term adaptive immune responses.

Congratulations to Maura Belanger et al, for completing and publishing many years of work in ACS Pharmacology & Translational Science, 2021.

Acute Lymph Node Slices Are a Functional Model System to Study Immunity Ex Vivo

This work establishes our best practices for collection of murine lymph node slices, demonstrates a lack of overt inflammation from the process of slicing, and characterizes their ability to respond to direct and indirect T cell stimulation. Finally, it provides some of the first evidence that lymph node slices from vaccinated animals can response to antigen ex vivo. We look forward to continuing to share this platform with other researchers.

Detergent wash improves vaccinated lymph node handling ex vivo

Congratulations to Alex Ball et al, who recently solved a longstanding bottleneck in our lab. We found that lymph nodes from vaccinated animals were the most difficult to slice, because did often failed to adhere to the supporting agarose hydrogel. Alex worked out a simple method to solve this problem, via a quick dip in a gentle detergent solution. We share this technical advance in the Journal of Immunological Methods, 2021.

Congratulations to Maura, Alex, and the entire team!

New paper: Mapping glucose uptake in live tissues

Our newest paper is out in Analytica Chimica Acta. Austin Dunn and Meg Catterton established a robust, optimized protocol to image glucose uptake in living tissues ex vivo. You can see heterogeneity across the tissue, and changes over time! We tested it in lymph node slices and were able to detect the response to T cell stimulation. Congrats Austin and Meg for this very useful work!

Austin F. Dunn, Megan A. Catterton, Drake D. Dixon(#), and Rebecca R. Pompano. “Spatially resolved measurement of dynamic glucose uptake in live ex vivo tissues.” Analytica Chimica Acta (2020). Online before print. [link].

Paper: Quantifying protein functionalization

New bioanalytical paper online last week! If you work with modified protein-based biomaterials, especially gelatin, this paper is for you. We describe optimized, validated methods to see just how modified it really is.

Read it here.

“Quantification of fractional and absolute functionalization of gelatin hydrogels by optimized ninhydrin assay and 1H NMR”

This work is extra special because it originated as a summer project for then brand-new graduate student, Jon Zatorski, and talented undergrad Alyssa Montalbine. They took the idea of improving the ninhydrin assay and ran with it. Jon pioneered the NMR work, the first to do so in our lab. (Thanks Jeff Elena in NMR core!)

Honored to have this work featured in Analytical and Bioanalytical Chemistry as part of the "Female Role Models in Analytical Chemistry" topical collection, alongside Jill Venton, Ashley Ross, and ~60 other inspiring women.