Micromachined glass apertures for artificial lipid bilayer formation in a microfluidic system

The use of spark assisted chemical engraving (SACE) to produce glass apertures that are suitable for the formation of artificial bilayer lipid membranes is described. Prior to use, the glass apertures were rendered hydrophobic by a silanization process and were then incorporated into a simple microfluidic device. Successful bilayer lipid membrane (BLM) formation and the subsequent acquisition of single-channel recordings are demonstrated. Due to the simplicity and rapidity of the SACE process, these glass apertures could be easily integrated into an all-glass microfluidic system for BLM formation

Identification of formation stages in a polymeric foam customised by sonication via electrical resistivity measurements

The polymerisation reactions associated with foam formation have distinct stages (i.e. nucleation, growth, packing, stiffening, solidification) some of which are known to be more sensitive to external inputs than others. Consequently, precise detection of the start and end points of each of the polymerisation stages would enable the fine control of material properties such as porosity in solid foams. The development of such process control can only be pursued if those sensitive stages can be clearly distinguished during the manufacture process. This paper reports how an electrical resistivity tracking method was used to assess the differences in the foaming processes when ultrasound was irradiated to polymeric melts undergoing foaming with the aim of tailoring the architecture of the final solid matrix. The electrical resistivity tracking method is also appraised with regard to its suitability to accurately identify the formation stages in the foam

Dynamic Light Scattering Based Microelectrophoresis: Main Prospects and Limitations

Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation averaging, are revisited in this work. Along with that, the main prospects of these two analytical methods are mentioned. A detailed review of the role of zeta potential in processes of biochemical nature is given too. It is argued that although zeta potential has been used as one of the main parameters in controlling the stability of colloidal dispersions, its application potentials are much broader. Manipulating surface charges of interacting species in designing complex soft matter morphologies using the concept of zeta potential, intensively investigated recently, is given as one of the examples. Branching out from the field of colloid chemistry, DLS and zeta potential analyses are now increasingly finding application in drug delivery, biotechnologies, physical chemistry of nanoscale phenomena and other research fields that stand on the frontier of the contemporary science. Coupling the DLS-based microelectrophoretic systems with complementary characterization methods is mentioned as one of the prosperous paths for increasing the information output of these two analytical techniques