Dynamic Extracellular Imaging of Biochemical Cell Activity Using InGaN/GaN Nanowire Arrays as Nanophotonic Probes

Abstract

The application of InGaN/GaN nanowire heterostructure arrays as photonic probes for dynamic imaging of biochemical and cellular processes in an incident light fluorescence microscope is demonstrated. The photoluminescence intensity of InGaN/GaN nanowires sensitively depends on the pH value of the surrounding solution, making them suitable probes for the optical detection of biochemical processes accompanied by local pH variations. Grown on a conductive substrate, the nanowire arrays can be operated in a well-defined electrochemical working point with high sensitivity and stability. The achievable pH and bias resolution as well as signal-to-noise ratio are assessed as a function of the working point and for different integration times. A bias resolution of 1 mV and a pH resolution of 0.03 are achieved at a time resolution below 25 ms. The application for dynamic imaging of the activity of isolated intestinal crypts from Wistar rats is demonstrated. Here, the pH change in the vicinity of the crypt is quantified and attributed to the activity of the sodium-proton exchanger (NHE). Imaging of the effect of amiloride and NH 4 Cl on its activity is demonstrated with a spatial resolution of <0.63 µm and reveals that NH 4 Cl-induced NHE activation preferentially occurs in the upper part of the crypt.

Facile Synthesis of WS2/WO3 Materials in a Batch Reactor for the Hydrogen Evolution Reaction

“…New materials and breakthrough technologies are increasingly necessary to conserve energy and develop environmentally friendly energy sources. Tremendous efforts have been made to overcome the emerging environmental problems [6][7][8][9][10][11][12][13]. With the advent of cutting-edge technologies, hydrogen is one of the most prominent candidates as an ecosystemfriendly and reusable energy source [14][15][16][17][18][19][20][21].…”

Origin of the spectral red-shift and polarization patterns of self-assembled InGaN nanostructures on GaN nanowires

“…A large variety of different growth techniques in combination with their promising properties, such as high crystalline quality, 1 one-dimensionality, 2 and variability for functionalization, makes semiconductor NWs interesting for a wide field of applications ranging from transistors and solar energy harvesting, 3 light-emitting diodes and laser diodes, 1,[4][5][6] to photodetectors, waveguides, 4,7 and optochemical sensors. [8][9][10] Group-III-V NWs have attracted particular interest due to the tunability of the direct bandgap and improved material quality compared to bulk materials. 1,11 It has been shown that InGaN NW light-emitting diodes exhibit a reduced Auger recombination rate, i.e., a lower efficiency droop, 3 compared to bulk InGaN or InGaN quantum wells (QWs).…”

Atomic-scale investigation on the ultra-large bending behaviours of layered sodium titanate nanowires

“…One-dimensional (1D) nanomaterials have received extensive research interest in recent years along with the vast development of microelectronics, 1 energy, 2 environment, 3 biology, 4 and other fields. Similar to the applications of bulk materials, nanomaterials in integration and practical applications are subjected to mechanical deformation, especially in flexible devices and single nanowire (NW) based electronics.…”