# Oligonucleotide Selective Detection by Levitated Optomechanics

## TL;DR

This paper explores using levitated optomechanics to detect specific signals from oligonucleotides attached to silica nanoparticles.

## Contribution

A novel optomechanical method is introduced for detecting oligonucleotide-specific signals using functionalized silica nanoparticles in optical traps.

## Key findings

- Functionalized and nonfunctionalized nanoparticles showed distinct oscillation frequency and amplitude differences.
- Lorentzian curve fitting and random forest modeling confirmed significant differences between particle types.
- Transmission electron microscopy failed to visually distinguish between the particle types.

## Abstract

This study examines the detection of oligonucleotide-specific
signals
in sensitive optomechanical experiments. Silica nanoparticles were
functionalized using ZnCl2 and 25-mers of single-stranded
deoxyadenosine and deoxythymidine monophosphate which were optically
trapped by a 1550 nm wavelength laser in vacuum. In the optical trap,
silica nanoparticles behave as harmonic oscillators, and their oscillation
frequency and amplitude can be precisely detected by optical interferometry.
The data was compared across particle types, revealing differences
in frequency, width, and amplitude of peaks with respect to motion
of the silica nanoparticles which can be explained by a theoretical
model. Data obtained from this platform was analyzed by fitting Lorentzian
curves to the spectra. Dimensionality reduction detected differences
between the functionalized and nonfunctionalized silica nanoparticles.
Random forest modeling provided further evidence that the fitted data
were different between the groups. Transmission electron microscopy
was carried out but did not reveal any visual differences between
the particle types.