Degree

Doctor of Philosophy (PhD)

Department

Cain Department of Chemical Engineering

Document Type

Dissertation

Abstract

An object is chiral when it holds no lines of symmetry. This quality naturally occurs in chemistry and biology. When an object is chiral it has a unique handedness and objects of opposite chirality are called enantiomers. The importance of handedness was brought to light in the 1960’s when a racemic mixture of thalidomide enantiomers was given to pregnant women. One enantiomer was able to treat morning sickness while the other caused severe birth defects. This case brought to light how enantiomers have unique properties from each other even though they are similar materials. With this knowledge chiral nanomaterials must be carefully explored for biological treatments.

Although chiral pharmaceuticals can cause severe damage depending on the handedness of the drug, if studied the chiral responses of nanoparticles can be an advantage when used in medical applications. The unique chiroptical response of these materials makes them sensitive to their environment and how they interact with biological materials. The focus of this project is to improve the uniformity during the fabrication of chiral nanomaterials and understand the toxicity effects of the enantiomers to allow for biomedical applications. An increase in uniformity can enhance the optical responses to be better for biological applications.

Chiral nanoparticles exhibit chiroptical responses when they interact with circularly polarized light. Due to the occurrences of chirality in nature, the chiroptical responses of nanoparticles can be enhanced when they interact with biomaterials that are also chiral. Current fabrication methods face a tradeoff of uniformity and coverage for cost and time of fabrication. Another difficulty with fabricating chiral nanoparticles is making sure that the suspension is enantiomerically pure. One method to improve large scale fabrication of enantiomeric chiral nanoparticles is using tilt-rotate evaporation colloidal lithography (TRE-CL). TRE-CL allows pitch-to-hole-diameter ratios in chiral nanoparticle masks as high as 7:1 and diameters down to 60 nm while maintaining a nearly constant coefficient of variance (CV) below 10% and circularity above 91%. The use of TRE-CL for the fabrication of nanomaterials allows for more uniform structures. Fabricating these uniform enantiomer specific chiral plasmonic nanoparticles opens the door to better forms of treatment for diseases.

Date

8-24-2023

Committee Chair

Kevin M. McPeak

Download

Share

COinS