Electrochemical-QCMD Control over S-Layer (SbpA) Recrystallization with Fe2+ as Specific Ion for Self-Assembly Induction
| Autor: | Dietmar Pum, Uwe B. Sleytr, José L. Toca-Herrera, Jagoba Iturri, Andreas Breitwieser |
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| Rok vydání: | 2018 |
| Předmět: |
S-layers
0301 basic medicine Materials science QCMD chemistry.chemical_element 02 engineering and technology Electrochemistry lcsh:Technology iron salts Ferrous lcsh:Chemistry 03 medical and health sciences medicine General Materials Science lcsh:QH301-705.5 Instrumentation Fluid Flow and Transfer Processes chemistry.chemical_classification lcsh:T Process Chemistry and Technology General Engineering Recrystallization (metallurgy) self-assembly Quartz crystal microbalance 021001 nanoscience & nanotechnology lcsh:QC1-999 Computer Science Applications Nickel 030104 developmental biology electrochemistry lcsh:Biology (General) lcsh:QD1-999 Chemical engineering chemistry lcsh:TA1-2040 Ferric Self-assembly Counterion lcsh:Engineering (General). Civil engineering (General) 0210 nano-technology lcsh:Physics medicine.drug |
| Zdroj: | Applied Sciences, Vol 8, Iss 9, p 1460 (2018) Applied Sciences Volume 8 Issue 9 |
| ISSN: | 2076-3417 |
| DOI: | 10.3390/app8091460 |
| Popis: | The critical role of divalent ions (M² +) in the self-assembly of SbpA S-layer proteins (from Lysinibacillus sphaericus CCM 2177) into crystalline structures has been reported in several studies. Hence, ions such as magnesium, barium, nickel and, most commonly, calcium (Ca² +) have proven to trigger both protein-protein and protein-substrate interactions involved in the two-stage non-classical pathway recrystallization followed by SbpA units. As a result, two dimensional, crystalline nanometric sheets in a highly ordered tetrameric state (p4) can be formed on top of different surfaces. The use of iron in its ferrous state (Fe2+) as self-assembly inducing candidate has been omitted so far due to its instability under aerobic conditions, tending to natural oxidation to the ferric (Fe3+) state. In this work, the potentiality of assembling fully functional S-layers from iron (II) salts (FeCl2 and FeSO4) is described for the first time. A combination of chemical (oxidation retardants) and electrical (&minus 1 V potential) factors has been applied to effectively act against such an oxidizing trend. Formation of the respective crystalline films has been followed by means of Electrochemical Quartz Crystal Microbalance with Dissipation (EQCM-D) measurements and complementary Atomic Force Microscopy (AFM) topography studies, which prove the presence of squared lattice symmetry at the end of the recrystallization process. Both techniques, together with additional electrochemical tests performed over the ion permeability of both types of S-layer coatings formed, show the influence of the counterion chosen (chloride vs. sulphate) in the final packing and performance of the S-layer. The presence of an underlying Secondary Cell Wall Polymer (SCWP) as in the natural case contributes to pair both systems, due to the high lateral motility freedom provided by this biopolymer to SbpA units in comparison to uncoated substrates. |
| Databáze: | OpenAIRE |
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