Synthesis, in vitro macrophage response and detoxification of bamboo charcoal beads for purifying blood

Bamboo charcoal beads (BCBs) were formed by coprecipitating bamboo charcoal particles with chitosan in alkaline solution. The amount of chitosan in the BCBs and their surface properties were measured. When 13-52 mg BCBs were exposed to RAW 264.7 macrophages, the amount of nitric oxide released and the cell viability were close to those of the blank. The amount of cytokine IL-6 secreted by macrophages did not depend on the dose of BCBs but macrophages secreted more TNF-alpha in response to higher doses of BCBs. However, the cytokine levels were relatively low, suggesting the favorable biocompatibility of BCBs. In adsorption experiments, BCBs adsorbed and released bovine serum albumin at particular concentrations, whereas BCBs adsorbed L-phenylalanine without a sign of release. This difference is attributed to the hydrophilicity and the pore size of the BCBs. Finally, the potential of BCBs as biocompatible adsorbents in blood detoxification is considered.