keith johnston research group nanotechnology/colloid ... · keith johnston research group...

Keith Johnston Research Group Nanotechnology/Colloid Science/Interfaces

kpj@che.utexas.edu

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 bartondear@gmail.com Ehsan Moaseri (Gold, AEC) CPE 5.430 ehsanmoaseri@utexas.edu

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 shehab.alzobaidi@utexas.edu Caleb Alexander (Electrochem.) CPE 5.426 calebta107@gmail.com

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