# Scanning Resonator Microscopy

> **NIH NIH R03** · UNIVERSITY OF KANSAS LAWRENCE · 2021 · $71,000

## Abstract

Summary
 Photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy
(STORM) have revolutionized the super-resolution field by introducing approaches that are reasonably
mastered and implemented in the end-user laboratory. Their impact is now felt across the disciplines where
their unique capabilities are being applied to an ever-expanding spectrum of important problems.
 Near-field scanning optical microscopy (NSOM) is another super-resolution technique that has
attributes complementary to those of PALM and STORM. NSOM is a scanning probe technique that uses
specially fabricated fiber optic probes to measure super-resolution fluorescence and sample topography,
simultaneously. This is particularly useful in the biological sciences, where cell shape and morphological
features can be compared directly with species specifically labeled in the fluorescence image. To date,
however, the impact of NSOM in the biological sciences has been modest. This is mainly due to
burdensome implementation requirements and poor performance of the fiber optic probes. To overcome
these challenges, we propose a completely new approach for integrating optical contrast mechanisms with
atomic force microscopy (AFM).
 Scanning resonator microscopy (SRM) uses a small dielectric microsphere attached at the end of
conventional AFM probe for super-resolution imaging. The approach exploits whispering gallery mode
(WGM) resonances excited in the attached resonator to sense or excite sample properties. Unlike
conventional NSOM, the probes are easily assembled under a dissecting microscope and SRM requires
only minimal modifications to commercial AFM platforms. This should enable widespread adoption in the
end user lab. We have developed a prototype SRM and demonstrated the feasibility of this approach by
simultaneously quantifying sample refractive index and topography of thin films with super-resolution. The
overall goal here is to develop the next generation SRM capable of simultaneous fluorescence, refractive
index, and topography measurements on complex biological samples.
 The research plan proposed here will: (Aim 1) develop a “ride along” fiber optic coupler for SRM tip
excitation that enables super-resolution fluorescence imaging on thick biological samples and (Aim 2) test,
validate, and benchmark SRM performance on a real biological system by studying annexin VI localization
in fixed human arterial smooth muscle cells following calcium stimulation. The successful completion of this
work will introduce a new super-resolution tool that can easily be adopted in the end user lab, with unique
capabilities complementary to existing technologies. For the future, it is easy to envision additional sensing
capabilities being integrated with SRM through specific coatings or modifications of the optical resonator at
the tip end.

## Key facts

- **NIH application ID:** 9954076
- **Project number:** 5R03EB027357-02
- **Recipient organization:** UNIVERSITY OF KANSAS LAWRENCE
- **Principal Investigator:** Robert C. Dunn
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $71,000
- **Award type:** 5
- **Project period:** 2019-07-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9954076

## Citation

> US National Institutes of Health, RePORTER application 9954076, Scanning Resonator Microscopy (5R03EB027357-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9954076. Licensed CC0.

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