The Radke Lab Professor Clay Radke Vasily Andreev, Mahendra Chhabra, Kendra Copley, Loddie Hagar, A.J. Howes, Elisa R. Porcel, Tatyana Svitova, Victoria Tran

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The Radke LabProfessor Clay RadkeVasily
Andreev, Mahendra Chhabra, Kendra Copley, Loddie
Hagar, A.J. Howes, Elisa R. Porcel, Tatyana
Svitova, Victoria Tran
Current Graduate Student Research
Future Projects
What is the Radke Lab?
Oxygen transport through Cornea and Soft Contact
Lens Cornea is an avascular tissue. It needs
environmental oxygen to sustain the metabolic
processes critical for normal function of the
eye. Wearing a soft contact lens (SCL) on the eye
impedes oxygen supply from the air during the day
and from the palpebral conjunctiva (the tissue in
the posterior surface of upper eyelid) during
sleep. This mass-transfer impediment may lead to
insufficient oxygen supply to the cornea
(hypoxia), which causes various health
complications, including corneal swelling,
corneal acidosis and loss of corneal
transparency. This is the driving force for
research in development of hypertransmissible
silicone-hydrogel soft contact lens. The goal of
my project is two-fold. Firstly, since there is
no standard technique to measure oxygen
permeability of hypertransmissible
silicone-hydrogel SCLs, we are working on a
design of an apparatus to measure oxygen
permeability of these SCLs. Also, we plan to
measure oxygen diffusivity and solubility of
silicone-hydrogel lenses to determine
structure-property relationship by using various
characterization techniques (SAXS, SANS, etc).
Secondly, there is lack of fundamental
understanding of relationship between hypoxia and
corneal cellular metabolism. We want to
understand this relationship by doing metabolic
modeling of cornea-contact lens system.
Surface and colloid science technology The Radke
Lab research focuses on combining principles of
surface and colloid science towards engineering
technologies where phase boundaries dictate
system behavior. We employ modern spectroscopic
tools along with molecular theory and simulation,
and continuum transport and reaction engineering
to provide quantitative description of
interfacial behavior important to technology
development. Specific areas of interest include
protein/polymer/surfactant adsorption from
solution, two-phase enzymatic catalysis,
interfacial surfactant transport, wetting and
spreading, colloid stability, dynamics and
stability of thin films, chromatography,
multiphase and disperse phase flow in porous
media, wettability of and chemical transport and
reaction in porous media, electrokinetics,
pore-level fluid mechanics, tear films, and
contact-lens coating and physical design.
Soft Contact-Lens Surface Phenomena wettability
enhancement, tear-film stability, fouling, and
bacterial adhesion. K. A. Copley and V. Tran For
best visual acuity and comfort, soft contact
lenses must be highly wettable to human tear.
Additionally, the lenses should be immune both to
protein and lipid fouling and to bacterial
adhesion. With these goals in mind, we have
developed several in-vitro techniques to measure
wettability, mimic fouling, and quantify
bacterial adhesion to soft contact lenses. We
have also investigated the efficacy of wetting
agents and performed a clinical study to test the
correlation among wettability, tear-film
stability and comfort.
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The purpose of this project is to study
interfacial enzymatic cleavage of proteins with
the goal of obtaining a better understanding of
the mechanism and kinetics of enzyme action in
commercial detergent formulations. Historically,
enzyme performance has been empirically
optimized, so further improvements will require
a more detailed study of the enzyme-surface
interactions, enzyme surfactant interactions, as
well as the effect of other detergent additives
(builders, polymers, peroxide, etc.). Model
protein "stain" substrates were developed on
silicon wafers in order to utilize techniques
such as ellipsometry, optical waveguide light
spectroscopy (OWLS), and atomic force microscopy
(AFM). This will allow the determination of
protein content and morphology on the surface as
a function of time, enzyme concentration,
surfactant concentration, etc.
Surfactants are molecules that reduce the
interfacial tension between two fluid phases. In
addition, they exhibit various other phenomena,
such as micellization, emulsification, and
detergency. Along with detergents, surfactants
are appearing in new technologies, such as lung
surfactant and micelle drug delivery systems.
These technologies are reversible systems
thereby the properties of interest are
thermodynamically relevant. For example, surface
tension and surface concentration are two such
properties. My work seeks the accurate prediction
of these properties via thermodynamic models and
Monte Carlo simulations.