Dr Kevin Critchley

Introduction

The interaction of inorganic nanoparticles at biological interfaces is a fascinating field. I am developing a wide range of nanomaterials that can be used for sensing, imaging, and therapeutics. This includes the synthesis of the materials and engineering the morphology, size, and surface chemistry to enable optimisation the desired application. For example, I am developing cadmium-free quantum dots for applications towards bioimaging. An important aspect is the ability to tune the surface chemistry using organic molecules and biomolecules finely. I collaborate with colleagues at St. James Hospital to make a future impact in medicine. I am currently performing an EPSRC funded Healthcare Discipline Hop.

Current major projects

  • Green synthesis of nanoparticles using peptide sequences.
  • Intracellular redox sensing using quantum dots.
  • Photothermal active nanoparticles for efficient cancer treatment.
  • Deformation induced uptake of nanoparticles into live cells in a high throughput device.

Detailed research programme

Green synthesis of nanoparticles

Green synthesis of nanoparticles can be achieved using biomolecules which can control the reduction and stabilise the surface to produce well-defined nanoparticles. In this project we are working with partners at Tokyo Institute of Technology, who screen for short peptide sequences that produce nanoparticles under mild conditions. We are currently investigating gold and cadmium telluride materials, but will be extending this to other materials.

Intercellular Redox sensing can be achieved using quantum dots

Quantum dots are highly fluorescent and make excellent imaging probes. By attaching quinones to the surface the quantum dots emission can be quenched under an oxidising environment. By monitoring the fluorescence intensity the redox potential could be determined.

Gold nanorods

Gold nanorods strongly absorb near infrared light. They do this because of a strong longitudinal surface plasmon resonance. Almost all of this energy is converted into heat and thus when the nanoparticles are irradiated, the light heats the local environment. Heating above ~42 degrees Celsius can cause apoptosis in cancer cells and thus it is thought that thermal treatments could be enhanced by nanomaterials such as these. This is called photothermal therapy.

Cellular Nanoparticle Uptake

Cellular Nanoparticle Uptake can be achieved using microfluidic devices where the cells flow through the device and are deformed. The deformation within the device causes pores to form in the cell membranes and enable non-endocytic uptake. We are investigating this process using quantum dots as an example material to assess the uptake efficency.