Search

The use of a nanostructured aluminum substrate as the cathode for a perovskite photovoltaic device is described. This cathode consists of an aluminum substrate onto which a highly ordered array of aluminum oxide tubular pores was grown via anodization. The 1-mu m thick pores - arranged in a closed-packed hexagonal pattern - were subsequently selectively etched at the bottom to remove the so-called aluminum oxide barrier layer. The subsequent infiltration of the pores with the components of a methylammonium lead iodide perovskite solar cells, and the completion with a semi-transparent anode, have shown to allow the establishment of an ohmic contact between the substrate itself and the components infiltrated into the Al2O3 pores. Indeed, a clear rectifying behavior was observed on the full devices, as well as modest photovoltaic conversion efficiencies. This paper demonstrates that an ohmic contact can be established between the aluminum substrate from which nanoporous anodic alumina was grown, and that the pores can be used to compartmentalize the infill material down to the nanoscopic level.

This paper is an overview of the recent advances in nanoporous anodic alumina sensing platforms based on the interaction of oligonucleotides and antibodies with bioelements (e.g., virus, bacteria, or biomarkers) that can cause or identify diseases. Nanoporous alumina is the common platform material for all these sensing devices that have an enormous potential for the next-generation bioanalytical systems. Nanoporous alumina is a cost-effective material with morphological flexibility that provides high sensitivity to the sensing systems due to its large surface-to-volume ratio. Immunosensors transduce the signal produced by the specific antibody-antigen interaction. They are widely used for clinical analysis due to the high selectivity and sensitivity of their immunoreaction, transduced by different methods (electrochemical, optical, piezoelectric, etc). Another important, outstanding and more recently type of biosensors are based on the oligonucleotic functionalization of nanoporous alumina. Oligonucleotides can bind to a wide variety of elements (small organic molecules, proteins, or cells) with high selectivity, specificity, and affinity, even higher to those of antibodies. The basic concepts and mechanisms of their sensing methods for health care biosensing are introduced. Their transduction methods and great potential applications will be evaluated and classified in detail, together with a discussion of possible future trends.

This work demonstrates an advanced approach to fabricate Hybrid nanoporous anodic alumina gradient-index filters (Hy-NAA-GIFs) through a heterogeneous anodization process combining sinusoidal current-density anodization and constant potential anodization. As a result, the hybrid structure obtained reveals a single photonic stopband (PSB), which falls within the absorption region of the drug molecule and the intensity of the spectrum that are far from such absorption range. The prepared structures were loaded with the doxorubicin (DOX) drug through the drop-casting method, which allows for evaluating the maximum reflectance of the relative height of the PSB with the average reflectance of the spectrum intensity. Thereafter, this property has been applied in a flow cell setup connected to a reflectance spectrophotometer where different drug-loaded samples were placed to study the behavior and kinetics of the drug release in real-time by varying two parameters, i.e., different pore length and flow rates. As such, obtained results were analyzed with a model that includes a sum of two inverted exponential decay functions with two different characteristic time releases. Overall, this study opens up several possibilities for the Hy-NAA-GIFs to study the drug kinetics from nanoporous structures.

In this work, a methodology that exploits the optical properties of the nanoporous anodic alumina gradient index filters (NAA-GIFs) has been developed and applied to evaluate in real time the release dynamics of a cargo molecule, acting as a model drug, filling the pores. NAA-GIFs with two photonic stopbands (PSBs) were prepared with one of its stop bands in the same absorption wavelength range of the cargo molecule, whereas the second stopband away from this absorption range. Numerical simulation and experiments confirm that the relative height of the high reflectance bands in the reflectance spectra of NAA-GIFs filled with the drug can be related to the relative amount of drug filling the pores. This property has been applied in a flow cell setup to measure in real-time the release dynamics of NAA-GIFs with the inner pore surface modified by layer-by-layer deposition of polyelectrolytes and loaded with the cargo molecule. The methodology developed in this work acts as a tool for the study of drug delivery from porous nanostructures.

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch), This work is part of the interlaboratory collaboration to study the stability of organic solar cells containing PCDTBT polymer as a donor material. The varieties of the OPV devices with different device architectures, electrode materials, encapsulation, and device dimensions were prepared by seven research laboratories. Sets of identical devices were aged according to four different protocols: shelf lifetime, laboratory weathering under simulated illumination at ambient temperature, laboratory weathering under simulated illumination, and elevated temperature (65°C) and daylight outdoor weathering under sunlight. The results generated in this study allow us to outline several general conclusions related to PCDTBT-based bulk heterojunction (BHJ) solar cells. The results herein reported can be considered as practical guidance for the realization of stabilization approaches in BHJ solar cells containing PCDTBT.

Aptamer biosensors are one of the most powerful techniques in biosensing. Achieving the best platform to use in aptamer biosensors typically includes crucial chemical modifications that enable aptamer immobilization on the surface in the most efficient manner. These chemical modifications must be well defined. In this work we propose nanoporous anodic alumina (NAA) chemically modified with streptavidin as a platform for aptamer immobilization. The immobilization of biotinylated thrombin binding aptamer (TBA) was monitored in real time by means of reflective interferometric spectroscopy (RIfS). The study has permitted to characterize in real time the path to immobilize TBA on the inner pore walls of NAA. Furthermore, this study provides an accurate label-free method to detect thrombin in real-time with high affinity and specificity.

In Ciammaruchi et al.,1 the affiliation of Vida Turkovic, Horst-Gunter Rubahn, and Morten Madsen was erroneously changed during revision. The correct affiliation is as follows: Vida Turkovic, Horst-Gunter Rubahn, and Morten Madsen. SDU Nano SYD, Mads Clausen Institute, University of Southern Denmark, Sonderborg 6400, Denmark. The publisher regrets this error.