At the virtual 2025 ISS Research and Development Conference (ISSDRC), Joe A. Adam of Rensselaer Polytechnic Institute, presented the topic titled “Surface Science in Microgravity – Fluid Geometry in the Ring-Sheared Drop,” presented to a broad audience from academia and the scientific community during the Physical Sciences and Materials Development session.

Dr. Adam provided a comprehensive overview of the Ring Sheared Drop (RSD) hardware, experiment campaigns and the evolving role of RSD in advancing biophysical science, particularly in the characterization of proteins. Leveraging the absence of gravity aboard the ISS, the RSD enables researchers to isolate shear-induced aggregation processes relevant to neurodegenerative diseases such as Alzheimer’s and Parkinson’s, offering insight into mechanisms that are difficult to observe with ground-based experiments.

The presentation traced the RSD development, beginning with the initial campaign in 2016 which was funded by Biological and Physical Sciences (BPS) for hardware development and the first science campaign, and culminating in the most recent 2025 flight campaign, which involved the study of three key proteins: Immunoglobulin G (IgG), Insulin, and Human Serum Albumin (HSA).

A highlight of the session was a discussion of the RSD’s custom camera configuration, which has enabled a novel fluid characterization technique known as Particle Tracking Velocimetry (PTV). This method allows researchers to visually track particle motion within the fluid drop, supporting the validation and refinement of theoretical and computational models describing protein behavior in microgravity.

Adam further explained how in-situ imaging and velocimetry techniques, enabled by the unique RSD camera setup, enhance the analysis of fluid flow and shear-driven aggregation at the molecular level.

The presentation showcased a series of comparative videos from past and current RSD campaigns, illustrating protein dynamics under varying sample compositions. He emphasized how flight data are being compared against Earth analog experiments to 1) validate predictive models and 2) inform the design of future microgravity research – the two-fold focus of the research from the beginning.

The session concluded with a summary of preliminary findings from the 2025 campaign, including multi-geometry rheometry results, which offer deeper insight into the viscoelastic behavior of proteins under shear. These findings may well contribute to the development of future pharmaceutical and therapeutic strategies.

To view the entire presentation, a recording is available for downloaded from the 2025 ISSRDC site.

Visit the Physical Sciences Informatics (PSI) database to access experiment data from two RSD campaigns, Interfacial Bioprocessing of Pharmaceuticals (IBP-I) and Amyloid Fibril Formation (AFF) with additional RSD data planned for release in 2026.