Thesis

A conjunction of spheres : colloidal quantum dot microlasers towards chipscale biosensors

Downloadable Content

Download PDF
Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T17678
Person Identifier (Local)
  • 202084509
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Biosensing is one of the most important current areas of research with the COVID19 pandemic highlighting the need for easy to use, reliable, and portable biosensors. Whispering Gallery Mode (WGM) lasers have been a popular choice for biosensing research due to their capability for label-free sensing, rapid detection response, high sensitivity, and high signal to noise ratio when operating above the lasing threshold. Colloidal Quantum Dots (CQDs) are an important class of new material and are attractive for use in lasers due to their high density of states, high photostability, and high quantum yield. In 2018, the fabrication of microspheres consisting entirely of CQDs, called supraparticles (SPs), which could demonstrate WGM lasing was first published and inspired a new area of research due to their promising use as tiny lasers. In this work, the focus was on the use of these CQD supraparticles (SPs) as laser biosensors because the microscale size of these SP lasers would enable their integration into a microfluidic chip to create easy to use and portable devices. First, the fabrication of these SPs was achieved using an emulsion templated fabrication, along with two additional variants, yielding SPs with laser thresholds as low as 4.1 ± 0.4 mJ/cm2 under free space excitation. To be able to use these SPs as laser biosensors, SPs were modified with the protein Neutravidin and a DNA aptamer with 15 bases called the Thrombin Binding Aptamer (TBA-15). Both Neutravidin-coated SPs and TBA-15 coated SPs (TBA-SPs) retained lasing functionality post- functionalisation with thresholds of 25.1 ± 3.5 mJ/cm2 and 19.8 ± 2.7 mJ/cm2 , respectively. Finally, a crude study to demonstrate biosensing capabilities of TBA-SPs for the protein thrombin in solution, with a possible detection limit around 1.5 mg/mL. This is an exciting new development which can act as a platform for further study and to create a lab on a chip sensing device.
Advisor / supervisor
  • Laurand, Nicolas
Resource Type
DOI

Relations

Items

Thumbnail Title Date Uploaded Visibility Actions
file details PDF of thesis T17678 2026-03-30 Public Download