Sample Data Sample Data 24.95 ut 0 15 30 45 60 75 90 105 - PowerPoint PPT Presentation

P rotein Adsorption rotein Adsorption on Solid Surfaces Solid Surfaces on Chemical Engineering and Materials Kim-Lien Thi Dinh Major: Biochemistry Pasadena City College Mentor: Kenny Rosenberg Faculty Advisor: Jacob Israelachvili University of California, Santa Barbara

R esearch and Motivation esearch and Motivation • Fundamental: Understand the interactions of protein – Protein-protein interactions – Surface-protein interactions • How much protein is on the surface? • What would happen if…? • Extend the life span of a biomedical implant – Implant rejected by the body due to protein adsorption – Decrease the adsorption of protein • Funding: National Institute of Health – Improve people’s health – Prevent diseases/find causes and cures for diseases

S urface-Protein Interactions urface-Protein Interactions How much protein is on the surface? • Proteins – BSA (bovine serum albumin) – Tau • Surfaces – Gold – Mica 0.0000 g 0.0000 g 3.0000 g 1.0000 g • Glue it on the crystal • Make sure it works balance balance balance balance • Need a “balance” – Quartz Crystal Microbalance (QCM) • Super-sensitive balance • Detects the mass of adsorbed protein

Q -Sense D300 -Sense D300 q-sense.com/Q-Sense D300 User Manual -100 Hz 15,000,000.00 Hz 14,999,900.00 Hz (15 MHz) -50 Hz 15,000,000.00 Hz 14,999,950.00 Hz (15 MHz)

25.15 Temp(Celcius) 25.05 Sample Data Sample Data 24.95 ut 0 15 30 45 60 75 90 105 Time (minutes) How much BSA protein is 5 mg/ml BSA with 200 mM NaCl (15 Mhz) on the gold surface? 20 1 monolayer of BSA ≈ 15 ng ∆ F req u en cy (H z ) 0 0 15 30 45 60 75 90 105 -20 -40 - 80 Hz ≈ 22 ng Addition of BSA -60 -80 - 95 Hz ≈ 26 ng -100 -120 Time (minutes) Dissipation 1.2 Dissipation X 1E-6 Sum of all energy losses in 0.8 the system per 0.4 oscillation cycle 0 0 15 30 45 60 75 90 105 Soft/rigid film -0.4 Time (minutes)

GOLD MICA 3 nm 10 nm 2 nm 5 nm 0.25 µ m 0.25 µ m 0 nm 0 nm AFM AFM 1 µ m 1 µ m 1 µ m 1 µ m 0.5 µ m 0.5 µ m 0.5 µ m 0.5 µ m 0 µ m 0 µ m Gold vs. Mica

pH 4.77 pH 6.80 pH 10.15 5 nm 2 nm 2 nm 2.5 nm 1 nm 1 nm 0.5 µ m 0.5 µ m 0.5 µ m 0 nm 0 nm 0 nm AFM AFM AFM 2.5 µ m 2.5 µ m 2.5 µ m 0 µ m 0 µ m 0 µ m Preliminaries: 1mg/ml BSA on Mica Does the pH of the solution matter?

2 nm 2 nm 1 nm 1 nm 0.25 µ m 0.25 µ m 0 nm 0 nm AFM AFM Preliminaries: Tau on Mica Does Tau concentration matter?

1mg/ml BSA with Acetic Buffer, pH 4.77 40 Addition of BSA BSA on Gold BSA on Gold 0 0 10 20 30 40 50 60 70 80 90 100 ∆ Frequency (Hz) -40 Does the pH of the -80 solution matter? First rinse -120 -160 1 monolayer of BSA ≈ 15 ng -200 Time (minutes) 1 mg/ml BSA with Carbonate Buffer pH 10.15 5 Addition of BSA - 170 Hz ≈ 48 ng (3 layers) 0 ∆ Frequency (Hz) 0 50 100 150 200 250 - 13 Hz ≈ 3.5 ng -5 -10 First rinse 1mg/ml BSA on Gold -15 -20 Does the pH of the solution matter? Time (minutes)

1 mg/ml BSA with K-PIPES, 1000mM NaNO3, pH 6.80 100 BSA on Gold BSA on Gold Addition of BSA ∆ Frequency (H z) 0 0 5 10 15 20 25 30 -100 Does salt concentration First rinse matter? -200 -300 -400 1 monolayer of BSA ≈ 15 ng Second rinse Time (minutes) 1 mg/ml BSA with K-PIPES, 1mM NaNO3, pH 6.8 20 0 ∆ Frequency (Hz) - 80 Hz ≈ 22 ng 0 5 10 15 20 25 30 -20 Addition of BSA - 300 Hz ≈ 83 ng (5.5 layers) -40 First rinse -60 -80 -100 Time (minutes)

S ummary and Future Research ummary and Future Research • It takes less than 5 seconds for the majority of the protein to adsorb onto the surface • pH of the solution matters • Salt concentration matters too • Produce a mica-modified crystal that works • Study Tau

• INSET – Trevor Hirst A cknowledgements – Dr. Nick Arnold cknowledgements – Liu-Yen Kramer – Mike Northen • Stu Feinstein • UCSB, CNSI, PCC, ME KENNY ROSENBERG Jacob Israelachvili and friends