# MagSToNE - a magnetic system for kidney stone fragment elimination

> **NIH NIH R21** · STANFORD UNIVERSITY · 2021 · $196,750

## Abstract

Project Summary
Urinary (kidney) stone disease is common and affects about 1 in 11 people in the United States, costing > $2
billion in healthcare expenditures per year in the United States. Current endoscopic surgical treatment of urinary
stone disease is centered around ureteroscopic laser lithotripsy to fragment the stone into smaller parts. The
fragments are either actively retrieved from the body one by one with a wire basket or left to pass spontaneously.
Depending on the size of the stone fragments, the process can be inefficient, tedious, and time-consuming in
the operating room which is expensive. Rendering a patient stone-free is the best way to prevent further
complications or repeat interventions due to residual stone fragments, yet current stone-free rates only approach
60-75%. The long-term goal is to improve clinical outcomes by achieving higher stone-free rates in a shorter
amount of time. The objective of this R21 application is to develop, characterize, and test the feasibility of a novel
magnetic-based technology to improve kidney stone fragment retrieval.
We propose MagSToNE (Magnetic System for Total Nephrolith Elimination), a new approach based on
magnetic nanotechnology for efficient stone fragment retrieval. MagSToNE consists of a flexible magnetic wire
with a biocompatible plastic sheath, and superparamagnetic particles which are functionalized to bind to kidney
stones. The magnetic wire is compatible with standard ureteroscopes and is similar in size to the guidewires
routinely used in ureteroscopy. It is additionally uniquely designed to generate much stronger magnetic field
gradients than a typical magnet. After laser fragmentation of a kidney stone, stone fragments are coated with
magnetic nanoparticles which have been functionalized to bind to kidney stones. The stones can then be easily
retrieved en masse by the magnetic wire, improving the efficiency of stone clearance compared to the
conventional wire basket.
This technology will be developed through the following specific aims: (1) to develop and optimize the
superparamagnetic particles and magnetic wire to capture and retrieve stone fragments; and (2) to compare the
performance of MagSToNE to conventional stone retrieval methods, with in vivo feasibility and
biodistribution/toxicity studies in a porcine model. This project is innovative in that it shifts the paradigm of stone
clearance from one based purely on mechanical retrieval to one that utilizes attractive magnetic forces and
promises better performance. The proposed research is significant because it has the potential to substantially
improve clinical outcomes and reduce healthcare costs related to kidney stone surgery.

## Key facts

- **NIH application ID:** 10354258
- **Project number:** 1R21DK131776-01
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** JOSEPH C LIAO
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $196,750
- **Award type:** 1
- **Project period:** 2021-09-21 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10354258

## Citation

> US National Institutes of Health, RePORTER application 10354258, MagSToNE - a magnetic system for kidney stone fragment elimination (1R21DK131776-01). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10354258. Licensed CC0.

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