A novel method for the detection of an assortment of environmental conditions in a microfluidic system using bacterial flagella and submicro-scale solid state pores is presented. Differences in various environmental conditions stimulate the polymorphic helix structure of Salmonella typhimurium flagella to transform to its lowest energetic conformation. By measuring the ionic current blockage (resistive pulse) as flagella electrophoretically translocate a submicro-scale pore, detection of the polymorphic state of flagella corresponding to the conditions of the environmental stimuli is possible. We test the viability of this method using purified depolymerized and repolymerized S. Typhimurium flagella and a high resolution electrical signal readout sub-micropore-based detection system.
The correct evaluation of the live time of a detection system is found to be important for correcting the counting loss of a multi-element detection system for fluorescent XAFS experiments. Synchronous resetting of preamplifiers and the suspension of electronics during the reset period is an effective method. The dead time of the incoming count rate should also be corrected, since its non-linearity cannot be neglected. A 19-element solid-state detector system which can count up to 3.7 × 105 counts s−1 channel−1 with <270 eV FWHM for Mn Kα has been realized; the dead time was independent of the incoming photon energy.
Analytical Currents: Defining the molecular forces that shape protein nanofibrils | Understanding noise in solid-state nanopores | DataChip tackles high-throughput drug screening | Dielectrophoresis with reconfigurable oil barriers | A multiwell, multicantilever, protein detection system | Proteomic profiling method not suitable for detecting prostate cancer | Whole-organism imaging MS | MALDI MS of transition-metal catalysts | Bard and Moerner win the 2008 Wolf Prize in Chemistry
