Nanoporous activated carbon beads and monolithic columns as effective hemoadsorbents for inflammatory cytokines.

The aim of the present study was to develop and investigate nanoporous activated carbon materials for their ability to adsorb inflammatory cytokines directly from blood, for a range of therapeutic applications, including: systemic inflammatory response syndrome (SIRS) related to sepsis, cardio-pulmonary by-pass surgery, or ischemic reperfusion injury. Building on the previously established relationship between the porous structure of beaded polymer-derived activated carbon and its capacity to adsorb inflammatory molecules, we have developed and characterized monolithic porous carbon columns produced from the same polymer precursor matrix as carbon microbeads. The monolithic columns developed were assessed for their ability to adsorb inflammatory molecules from blood in a circulating system. Preliminary findings demonstrated good removal of the inflammatory cytokines IL-8 (100% removal), IL-6 (80% removal), and TNF (51% removal) from blood. The efficiency of cleansing is dependent on the size of the adsorbed molecule and the porous structure of the monolith, highlighting their potential for use as a hemoadsorption device.

Inflammatory cytokine removal by an activated carbon device in a flowing system.

A prototype in-line filtration/adsorption device has been developed using novel synthetic pyrolysed carbon monoliths with controlled mesoporous domains of 2-50nm. Porosity was characterized by SEM and porosimetry. Removal of inflammatory cytokines TNF, IL-6, IL-1beta and IL-8 was assessed by filtering cytokine spiked human plasma through the walls of the carbon modules under pressure. The effect of carbon filtration on plasma clotting response and total plasma protein concentration was also assessed. Significant removal of the cytokines IL-6, IL-1beta and IL-8 was observed. Initially marked TNF removal diminished over time. The coagulation studies indicated that the carbon device does not exacerbate the propensity of blood plasma to clot. The total plasma protein concentration remained constant. The device offers a broader approach to the treatment of systemic inflammatory response syndrome (SIRS) by the removal of inflammatory mediators central to its progression.

The in vitro adsorption of cytokines by polymer-pyrolysed carbon.

This study investigated a range of phenol-formaldehyde-aniline-based pyrolysed carbon matrices and their component materials, for their ability to adsorb a range of inflammatory cytokines crucial to the progression of sepsis. The efficiency of adsorption of the target molecules from human plasma was assessed and compared to that of Adsorba 300C, a commercially available cellulose-coated activated charcoal. Results indicate that a number of the primary carbon/resin materials demonstrate efficient adsorption of the cytokines studied here (TNF, IL-6 and IL-8), comparable to other adsorbents under clinical investigation. Our findings also illustrate that these adsorbent capabilities are retained when the primary particles are combined to form a pyrolysed carbon matrix. This capability will enable the engineering of the carbon matrix porosity allowing a blend of carbonised particle combinations to be tailored for maximum adsorption of inflammatory cytokines. The present findings support further investigation of this carbon material as a combined carbon-based filtration/adsorbent device for direct blood purification.