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Keith Johnston Research Group Nanotechnology/Colloid Science/Interfaces
Protein stability and drug delivery • Morphology and protein-protein interactions • Rheology: subcutaneous injection Advanced Functional Nanomaterials (metals and metal oxides/polymers) • Control morphology/crystallinity via nucleation and growth in sol’n • Colloidal stability (ligands and polymers on the surface) • Optical, magnetic and electrocatalytic properties = f (morphology) • Biodegradable photonic Au nanoclusters for cancer imaging Nanoparticle Interact. with Liq. and Solid Interfaces • Oil/water and gas/water interfaces (emulsions and foams) • Solid surfaces (adsorption and transport in porous media)
Research Areas Low viscosity protein solutions for subcutaneous injection
Protein stability and drug delivery: (Graduate Students: Bart Dear, Jessica Hung)
Biodegradable Gold Nanoclusters for Imaging & Therapy
Biodegradable Au nanoclusters for imaging/therapy: (Graduate student: Ehsan Moaseri)
Sub-5 nm gold particles
Clustering of gold
nanoparticles
mediated by weakly
adsorbing polymer
PLA-b-PEG-b-PLA
Gold nanoparticle
bound together by
polymerSub-5 nm gold particles
Clustering of gold
nanoparticles
mediated by weakly
adsorbing polymer
PLA-b-PEG-b-PLA
Gold nanoparticle
bound together by
polymer
Graduate Student Contact Information
Bart Dear (Proteins) CPE 5.430 [email protected] Ehsan Moaseri (Gold, AEC) CPE 5.430 [email protected]
Recent publications: Foster, et al., Langmuir, 2014 Bagaria, et al., ACS Appl. Mater. Interfaces, 2013
Recent publications: Stover, et al., J. Phys. Chem., 2014, 118, 14291-98 Murthy, et al., ACS Nano, 2013, 7 (1), 239-251
Nanomaterials for Electrocatalysis
Φ(h)
h
vdW, depletion attr.
elect. rep.
steric
Lilyestrom (13)
• >20% of all biopharmaceuticals in clinical trials are mAbs • Treat cancer, autoimmune diseases, allergies and more • Small spacings at high conc – specific short-ranged
attraction cause association and high viscosity − Hydrogen bonds, anisotropic elect. attraction − Hydrophobic interactions
1
10
100
1000
50 100 150 200 250 300
Vis
co
sit
y (
cP
)
mAb concentration (mg/mL)
15:40 His(HCl):Mannitol
DI water
40:50:17 Tre:His:CitrA
50:50:12 Tre:His:PhosA
• Use co-solutes to mitigate attractive interactions to lower viscosity − Local anisotropic electrostatic attraction − Hydrophobic interactions − Depletion attraction
Arginine
Histidine
Trehalose
• Co-solutes, ex. (Arg), can be used to weaken interactions, reducing association and thus viscosity
• Techniques to measure mAb association − Light scattering (DLS, SLS, SAXS)
− Rheology/Viscosity vs. shear rate
0
25
50
75
100
100 1000 10000 100000
Vis
cosi
ty (
cP)
Shear Rate (s-1)
None
Arg-HCl
Co-solute
Monomer solution Network solution with
interaction sites
• Tune colloidal interactions to form nanoclusters
– Colloidal assembly based on free energy model
– Close spacing of gold particles produces intense NIR extinction
• Design reversibility and lack of protein adsorption for clearance Johnston, Sokolov, Truskett, Stover: ACS Nano (13), JACS (13), JPChem (14), Langmuir(16)
Shehab Alzobaidi (Subsurface) CPE 5.428 [email protected] Caleb Alexander (Electrochem.) CPE 5.426 [email protected]
Nanomaterials for electrocatalysis: (Graduate student: Caleb Alexander, Will Hardin, Tyler Mefford)
Recent publications: Hardin, Johnston, K.P. et al., J. Phys. Chem. Let. 2013 Hardin, Mefford, Johnston, K.P. et al., Chem. Mater. 2014, Nature Comm. 2016 Mefford, Hardin, Johnston, K.P. et al., Nature Mater. 2014
Subsurface Nanotechnology
Oxygen Evolution Reaction (OER) 4OH- → 2H2O + 4e- + O2
OER
High Surface Area Means High Rate
Metal 3d and Oxygen 2p density of states
should overlap!
Cao, Kruk. RSC Adv. 2014
Subsurface nanotechnology: (Graduate student: Shehab Alzobaidi, Carson Da, Chola Dandamudi)
monomer
propagating polymer
surface
Foster, et al., ACS Macro Letters (14)
20 nm
-150
-100
-50
0
50
100
150
-15,000 -10,000 -5,000 0 5,000 10,000 15,000
Mag
net
izat
ion
(e
mu
/g F
e)
H (Oe)
Zwitterionic Polymer/Magnetite Hybrids with High Magnetic Susceptibility and Mobility at High T and Salinity
Wormlike Micelles Impart Viscoelasticity for Ultra Dry Foams
0
50
100
150
200
250
0.75 0.85 0.95
Foam
Vis
cosi
ty (
cP)
Internal Phase Volume Fraction
3.6% SLES + 0.4% C10DMA + 2% KCl3.6% SLES + 2% KCl3.6% SLES in DIW
• 208 trillion m3 of CH4 in shale • 2~5 million gallons of water/well for disposal
Recent publications: Dear, et al., Pharm. Res., 2017, 34, 193-207 Borwankar, et al., Ind. Eng. Chem. Res., 2016 55, 11225-11234 Hung, et al., J Membr. Sci., 2016, 508, 113-126 Borwankar, et al., Soft Matter, 2013, 9, 1766-1771