University of Arkansas, Fayetteville


Disease-causing pathogens continue presenting enormous global health problems, especially due to their easy transmittance to people via water supply systems. The detection, filtration, and purification of bacteria-contaminated water samples are complex activities, ones subject to considerable error. Here we present a new and highly effective micro-fluidic system with carbon nanotube (CNT) clusters for effective and efficient detection, filtration, and purification of bacteria-contaminated medium. The developed system is based upon two unique properties of CNT clusters: high bacterial affinity and magnetic susceptibility. The CNTs 'high affinity to bacteria cells makes them a key candidate for the bacteria adsorption. The magnetic susceptibility of their clusters allows an effective way of separating as well as containing them in the system. Inthis study, we designed and tested a prototype CNT-cluster based micro-fluidic system by uniquely combining the two excellent properties of CNTs. The CNT-based micro-system consisted of a micro-channel, which positions CNT clusters evenly on the bottom surface using a strong Neodymium block (1 "X 1 "X 1 ") rare-earth magnet (surface magnetic field strength= 0.684 Testa). When bacteria suspensions were introduced, the CNT clusters in the micro-fluidic system were shown to effectively serve as bacterial adsorbing centers, which led to spontaneous adsorption and concentration of bacteria to the clusters. This was shown to happen for both types of microorganisms, i.e., Gram-positive and Gram-negative bacteria. The results demonstrate the excellent potential of the CNT based micro-fluidic system for bacteria capture, concentration, and separation.