National Science Foundation Adsorption of Proteins by Designed Carbons Yury Gogotsi, Drexel University, DMR Outcome: Researchers at Drexel University and University of Brighton, UK, have measured adsorption of proteins in designed porous carbide derived carbons (CDCs) and model carbon substrate – multiwalled carbon nanotubes (CNTs) as a function of pore size, volume, surface area, surface chemistry, and pH of the environment. Impact: CDC has been shown to selectively remove cytokines – mediators of sepsis – from blood plasma. Sepsis is a systemic inflammation responsible for the death of 1,500 people/day worldwide, on a scale comparable to lung and breast cancer. Explanation: CDCs with tuned porosity and modified surface chemistry are highly effective adsorbents for removal of cytokines and other proteins from biofluids. Removing cytokines from the blood may help to control the processes driving sepsis. The adsorption of large biotoxin molecules could offer potential protection against biological warfare. However, the mechanisms of protein adsorption on porous carbons are not fully understood. A better understanding of the nature of interaction between the protein molecules and carbon substrate is necessary to guide the development of new materials and devices with increased sorption capacity. Proteins adsorbed inside a carbon nanotube – only one of the many materials studied in this research project (courtesy V. Mochalin).

National Science Foundation Our goal was to develop Carbide Derived Carbon (CDC) based system for selective and efficient removal of cytokines from blood circulation. High levels of cytokines released by the human body is the main cause of mortality associated with sepsis, with death rate of 40-80%. We investigated adsorption of cytokines by CDC with tunable pore size, surface area, and surface chemistry; and identified the CDC material with optimal properties to remove >99% of cytokines from blood plasma within the first 60 min. The technology has been transferred to Y-Carbon ( for scale up and commercialization. Cytokines Removal by Designed Porous Carbons Yury Gogotsi, Drexel University, DMR SEM images of Ti2AlC-CDC and plots of CDC adsorption of the cytokine TNF-α from human plasma as a function of (a) CDC particle size, (b) annealing gas, (c) chlorination temperature; (d) a model of TNF-α. (Biomaterials, 2010; 31: )

National Science Foundation Understanding Effect of Carbon Surface Chemistry on Adsorption of Proteins Yury Gogotsi, Drexel University, DMR The adsorption of bovine serum albumin (BSA) and tumor necrosis factor-α (TNF-α) – a mediator of inflammation - was studied in a simple model porous material - carbon nanotubes (CNTs) grown by CVD in cylindrical pores of anodic alumina membranes. The use of CNTs with straight cylindrical pores with controllable surface chemistry allowed to separate the contribution of pores geometry and size from pores surface chemistry. The data showed that adsorption of the proteins depends on the channel diameter of the CNTs, the termination of CNTs surfaces, and the pH of medium. Amination of the carbon surface leads to increased adsorption of the protein at neutral pH, while oxidation decreases the sorption capacity. The differences have been explained by favorable or unfavorable electrostatic interactions between protein molecules and the carbon surface. TNF-α adsorption in channels of carbon nanotubes with a diameter of 180 nm in alumina membranes (as-deposited, annealed in air, and ammonia) at pH=7