Developmental mechanism of the periodic membrane skeleton in axons

Actin, spectrin, and associated molecules form a periodic sub-membrane lattice structure in axons. How this membrane skeleton is developed and why it preferentially forms in axons are unknown. Here, we studied the developmental mechanism of this lattice structure. We found that this structure emerged early during axon development and propagated from proximal regions to distal ends of axons. Components of the axon initial segment were recruited to the lattice late during development. Formation of the lattice was regulated by the local concentration of βII spectrin, which is higher in axons than in dendrites. Increasing the dendritic concentration of βII spectrin by overexpression or by knocking out ankyrin B induced the formation of the periodic structure in dendrites, demonstrating that the spectrin concentration is a key determinant in the preferential development of this structure in axons and that ankyrin B is critical for the polarized distribution of βII spectrin in neurites. DOI: http://dx.doi.org/10.7554/eLife.04581.00

Anti-stiction coating of PDMS moulds for rapid microchannel fabrication by double replica moulding

Abstract In this paper, we report a simple and precise method to rapidly replicate master structures for fast microchannel fabrication by double replica moulding of polydimethylsiloxane (PDMS). A PDMS mould was surface-treated by vapour phase deposition of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS), which resulted in an anti-stiction layer for the improved release after PDMS casting. The deposition of FDTS on an O 2 plasma-activated surface of PDMS produced a reproducible and well-performing anti-stiction monolayer of fluorocarbon, and we used the FDTS-coated moulds as micro-masters for rapid replication of micro-structures, avoiding the necessity to have to use other, more costly and fragile master materials. Our protocol has been shown to reliably fabricate PDMS-based microfluidic devices in a low-cost and efficient manner. The replicas were further employed as micro-contract stamps to fabricate polymer-based waveguides