Localized electrochemical impedance measurements on nafion membranes: Observation and analysis of spatially diverse proton transport using atomic force microscopy

2020 ◽  
Author(s):  
xiaojiang wang
Keyword(s):  
Atomic Force Microscopy ◽  
Proton Transport ◽  
Electrochemical Impedance ◽  
Impedance Measurements ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nafion Membranes

scholarly journals Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy

2016 ◽  
Vol 7 ◽  
pp. 220-227 ◽  
Author(s):  
Maryse D Nkoua Ngavouka ◽  
Pietro Capaldo ◽  
Elena Ambrosetti ◽  
Giacinto Scoles ◽  
Loredana Casalis ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Complementary Sequence ◽  
Single Base ◽  
Force Microscopy ◽  
Dna Monolayers ◽  
Atomic Force ◽  
The Difference

Background: DNA hybridization is at the basis of most current technologies for genotyping and sequencing, due to the unique properties of DNA base-pairing that guarantee a high grade of selectivity. Nonetheless the presence of single base mismatches or not perfectly matched sequences can affect the response of the devices and the major challenge is, nowadays, to distinguish a mismatch of a single base and, at the same time, unequivocally differentiate devices read-out of fully and partially matching sequences. Results: We present here two platforms based on different sensing strategies, to detect mismatched and/or perfectly matched complementary DNA strands hybridization into ssDNA oligonucleotide monolayers. The first platform exploits atomic force microscopy-based nanolithography to create ssDNA nano-arrays on gold surfaces. AFM topography measurements then monitor the variation of height of the nanostructures upon biorecognition and then follow annealing at different temperatures. This strategy allowed us to clearly detect the presence of mismatches. The second strategy exploits the change in capacitance at the interface between an ssDNA-functionalized gold electrode and the solution due to the hybridization process in a miniaturized electrochemical cell. Through electrochemical impedance spectroscopy measurements on extended ssDNA self-assembled monolayers we followed in real-time the variation of capacitance, being able to distinguish, through the difference in hybridization kinetics, not only the presence of single, double or triple mismatches in the complementary sequence, but also the position of the mismatched base pair with respect to the electrode surface. Conclusion: We demonstrate here two platforms based on different sensing strategies as sensitive and selective tools to discriminate mismatches. Our assays are ready for parallelization and can be used in the detection and quantification of single nucleotide mismatches in microRNAs or in genomic DNA.

Electrochemical and atomic force microscopy investigations of the effect of CdS on the local electrical properties of CH3NH3PbI3:CdS perovskite solar cells

2017 ◽  
Vol 5 (46) ◽  
pp. 12112-12120 ◽  
Author(s):  
Mingxuan Guo ◽  
Fumin Li ◽  
Lanyu Ling ◽  
Chong Chen
Keyword(s):  
Atomic Force Microscopy ◽  
Solar Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Bulk Heterojunction ◽  
Perovskite Solar Cells ◽  
Kelvin Probe ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force

The effect of the incorporated CdS on the local optoelectronic properties of CH3NH3PbI3:CdS bulk heterojunction (BHJ) perovskite solar cells (PSCs) are studied using Kelvin probe force microscopy (KPFM), conductive atomic force microscopy (c-AFM) and electrochemical impedance spectroscopy (EIS).

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