Poster Y11 - Microrobotic Grippers for Upper Urinary Tract Biopsy

Friday, October 25, 2024

10:00 AM - 11:00 AM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Wangqu Liu, PhD Candidate (he/him/his)

Research Assistant
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA, United States

Co-Author(s)

Ridwan Alam, MD, MPH

Fellow - Robotic Surgery and Minimally Invasive Urologic Oncology
Department of Urology, Northwestern University Feinberg School of Medicine, United States
SC

Si Young Choi

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA, United States
YW

Yan Wan

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA, United States
RZ

Ruili Zhang

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA, United States
EB

Ezra Baraban

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA, United States
AM

Andres Matoso

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA, United States
BM

Brian Matlaga

The James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA, United States
JW

Jared Winoker

Smith Institute for Urology, Lenox Hill Hospital, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, NY 10075, USA, United States

Primary Investigator(s)

David Gracias, PhD

Professor
Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Sidney Kimmel Comprehensive Cancer Center (SKCCC), Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Chemistry, Materials Science and Engineering, Laboratory for Computational Sensing and Robotics (LCSR), Johns Hopkins University, Baltimore, MD 21218, USA.
Baltimore, Maryland, United States

Introduction: Microrobots present a transformative potential for medical and surgical interventions in anatomically intricate and small regions, essential for addressing various diseases. Accessing the upper urinary tract, including the ureter and the pelvicalyceal system, is crucial for diagnosing and treating diseases such as Upper Tract Urothelial Carcinoma (UTUC). Challenges in this domain include adequate tissue sampling, precise disease grading, and targeted or extended medication delivery using existing ureteroscopic tools.

Materials and

Methods: We designed and microfabricated biopsy microgrippers (μ-grippers) with a pre-activation tip-to-tip size of 717 μm (Figures a and c), allowing deployment via a urinary catheter. These μ-grippers autonomously activate at body temperature, self-folding to capture tissue through the release of differential stress energy stored in their thin metal films, functioning like a triggered spring. After folding, the μ-grippers turn into micro cages with a size of about 200 μm and can be magnetically retrieved with biopsy samples for histopathological analyses (Figures b and d). Additionally, we can remotely steer the μ-grippers to precise locations using an external magnetic field.

Results, Conclusions, and Discussions: Our findings indicate that the μ-grippers can be delivered via clinically used urinary catheters with a delivery success rate ranging from 80 to 88%. The μ-grippers achieved magnetically controlled multimodal locomotion, such as moving, tumbling, and tearing, on ex vivo urothelial tissues. Upon activation, the μ-grippers effectively penetrated and gripped urothelial tissues. Experimental deployments on ex vivo pig ureters showed that the μ-grippers could successfully biopsy tissue, producing samples suitable for histopathological examination, including H&E and GATA3 immunostaining. The small size of the μ-grippers, combined with their potential for high-throughput, wafer-scale production, and multifunctionality, make them ideal for statistical sampling within the urinary tract. Our statistical simulations comparing the efficacy of μ-grippers with conventional ureteroscopic tools, such as forceps and baskets, highlight their superior performance. We anticipated that our μ-grippers will advance urinary tract tissue sampling, enhancing the early detection of small, low-grade, and hard-to-reach lesions.

Acknowledgements (Optional): We acknowledge discussions with Dr. Arijit Ghosh. Johns Hopkins University has filed patents related to the technology. Under an option to license agreement between Kley Dom Biomimetics, LLC and the Johns Hopkins University, Prof. D. H. Gracias and the Johns Hopkins University are entitled to royalty distributions related to the technology described in the study discussed in this publication.