Bio-electrostatic sensitive droplet lasers for molecular detection

Abstract

A bioelectrostatic responsive microlaser based on liquid crystal droplets was developed and explored for ultrasensitive detection of negatively charged biomolecules.

Review of biosensing with whispering-gallery mode lasers

“…In addition, the position of the droplets inside a given medium can be controlled using optical trapping, magnetic fields, electrodynamic ion traps (Paul traps) and ultrasonic waves 69 , 71 – 75 . Droplet-based resonators with liquid crystals as an integral component within the droplet offer an opportunity for tuning and tailoring droplet properties, such as the orientation of the LCs using electric fields 6 , 54 . Tuning of the droplet-based sensor can improve its sensitivity limits and makes it capable of sensing biomolecules with negative charges 6 .…”

“…Droplet-based resonators with liquid crystals as an integral component within the droplet offer an opportunity for tuning and tailoring droplet properties, such as the orientation of the LCs using electric fields 6 , 54 . Tuning of the droplet-based sensor can improve its sensitivity limits and makes it capable of sensing biomolecules with negative charges 6 . However, fabrication and tuning of LC droplets is complicated; therefore, their use for in vivo applications has not yet been demonstrated.…”

“…During the last few years, the application of microlasers, especially whispering-gallery mode (WGM) microlasers, in chemical and biological sensing has increased due to advances made in reducing the gap between laboratory experiments and their real-world application. A number of exciting applications of WGM lasers in biosensing have been reported, such as lasing within living cells 4 , monitoring contractility in cardiac tissue 5 , detection of molecular electrostatic changes at biointerfaces 6 , label-free detection of single virus particles 7 and advancement of in vivo sensing 4 , 8 , 9 . WGM microlasers with a liquid-core optical ring resonator (LCORR) can probe the properties of a gain medium introduced as a fluid into the core of a thin-walled glass capillary, thereby providing good sensitivity for the detection of health biomarkers such as DNA and protein molecules 10 , 11 .…”

Electrostatic-responsive microdroplet lasers for ultrasensitive molecular detection

“…Due to the interactions between LC molecules and biological targets, LC is high-sensitive to molecules anchoring and electrostatic force at interfaces. During the past several years, the LC biosensing platform has been explored in various forms, such as thin films [1][2][3][4][5] and microdroplets [6][7][8][9][10][11][12]. The orientation transition of LC molecules from homeotropic to planer (or from radial to bipolar) induced by biomolecules changing can be observed under a polarized optical microscope (POM) by the naked eye.…”

“…Recently, microlasers, as an emerging technology, attract widespread attention in the biomedical and biological fields. LC microsphere based whispering gallery mode (WGM) lasers, with the properties of high Q factor and compact cavities, have been demonstrated that it is a more sensitive method for biomolecules detection [7,9,[13][14][15]. The dye-doped LC droplet, as a microcavity, can generate the WGM laser and is used to be a sensing probe as well.…”