Electronic, Magnetic and Spin-polarized Transport Properties of the Zigzag-Zigzag Penta-graphene Nanoribbon

Electronic, magnetic and spin-polarized transport properties of the zigzag-zigzag pentagraphene nanoribbon are investigated theoretically within the framework of density functional theory combined with non-equilibrium Green’s function formalism. It is found that the spinunpolarized ZZ-PGNR behaves as metal. However, the spin-polarized ZZ-PGNRs show to be the magnetic semiconductor properties. More importantly, for the ZZ-PGNRs based device, the spin-filtering effect occurs strongly near Fermi level. Our findings suggest that ZZ-PGNRs might hold a significant promise for developing spintronic devices.

Matrix elasticity gradients guide neuronal polarity by controlling microtubule network mobility

Neuronal polarization and axon specification depend on extracellular cues, intracellular signaling, cytoskeletal rearrangements and polarized transport, but the interplay between these processes has remained unresolved. The polarized transport of kinesin-1 into a specific neurite is an early marker for axon identity, but the mechanisms that govern neurite selection and polarized transport are unknown. We show that extracellular elasticity gradients control polarized transport and axon specification, mediated by Rho-GTPases whose local activation is necessary and sufficient for polarized transport. Selective Kinesin-1 accumulation furthermore depends on differences in microtubule network mobility between neurites and local control over this mobility is necessary and sufficient for proper polarization, as shown using optogenetic anchoring of microtubules. Together, these results explain how mechanical cues can instruct polarized transport and axon specification.

Tight Junction Modulating Bioprobes for Drug Delivery System to the Brain: A Review

The blood-brain barrier (BBB), which is composed of endothelial cells, pericytes, astrocytes, and neurons, separates the brain extracellular fluid from the circulating blood, and maintains the homeostasis of the central nervous system (CNS). The BBB endothelial cells have well-developed tight junctions (TJs) and express specific polarized transport systems to tightly control the paracellular movements of solutes, ions, and water. There are two types of TJs: bicellular TJs (bTJs), which is a structure at the contact of two cells, and tricellular TJs (tTJs), which is a structure at the contact of three cells. Claudin-5 and angulin-1 are important components of bTJs and tTJs in the brain, respectively. Here, we review TJ-modulating bioprobes that enable drug delivery to the brain across the BBB, focusing on claudin-5 and angulin-1.