Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters

Polydimethylsiloxane (PDMS) is a promising biomaterial for generating artificial extracellular matrix (ECM) like patterned topographies, yet its hydrophobic nature limits its applicability to cell-based approaches.” Although plasma treatment can enhance the wettability of PDMS, the surface is known to recover its hydrophobicity within a few hours after exposure to air. *

To investigate the capability of a novel PDMS-type (X-PDMS) for in vitro based assessment of physiological cell properties, the authors of the article “Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters” cited here, designed and fabricated plane as well as nano- and micrometer-scaled pillar-patterned growth substrates using the elastomer types S-, H- and X-PDMS, which were fabricated from commercially available components.*

To assess their applicability to cell-based approaches, Marina Scharin-Mehlmann et al., characterized the generated surfaces using water contact angle (WCA) measurement and atomic force microscopy (AFM) as indicators of wettability and roughness, respectively.*

The surface roughness of the samples was determined by Atomic Force Microscopy in tapping mode. For plane and flat pillar patterned PDMS (130 and 190 nm nominal pillar height) surfaces, a standard tapping mode AFM probe ( Pointprobe® NCHR, NanoWorld) was used. For patterned surfaces with pillars of 1,800 nm height tilt compensated high-aspect-ratio AFM probes (AR5T-NCHR, NanoWorld) were used. The scanning area was 50 × 50 μm2, the scanning rate 0.5 Hz. In this scanning area each roughness value (root mean square roughness Rq) was evaluated from five 10 × 10 μm2 areas.*

Figure 5 from “Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters” by Marina Scharin-Mehlmann et al.: AFM analysis of structured PDMS substrates. (A) Three-dimensional reconstructions of fabricated pillar-structured PDMS substrates recorded by AFM. (B) Mean pillar height of plane S-, H-, and X-PDMS as measured by AFM. All data are significantly different at a significance level of P ≤ 0.001 as evaluated by two-way ANOVA unless otherwise indicated. Color coding of statistical analysis: within group “130 nm,” purple; within group “190 nm,” pink.

Figure 5 from “Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters” by Marina Scharin-Mehlmann et al.: AFM analysis of structured PDMS substrates. (A) Three-dimensional reconstructions of fabricated pillar-structured PDMS substrates recorded by AFM. (B) Mean pillar height of plane S-, H-, and X-PDMS as measured by AFM. All data are significantly different at a significance level of P ≤ 0.001 as evaluated by two-way ANOVA unless otherwise indicated. Color coding of statistical analysis: within group “130 nm,” purple; within group “190 nm,” pink.

*Marina Scharin-Mehlmann, Aaron Häring, Mathias Rommel, Tobias Dirnecker, Oliver Friedrich, Lothar Frey and Daniel F. Gilbert
Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters
Frontiers in Bioengineering and Biotechnology. 2018; 6: 51
DOI: 10.3389/fbioe.2018.00051

Please follow this external link to view the full article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938557/

Open Access: The article «Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters» by Marina Scharin-Mehlmann, Aaron Häring, Mathias Rommel, Tobias Dirnecker, Oliver Friedrich, Lothar Frey and Daniel F. Gilbert (2018) is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM

Composite carbon nanofibres (CNFs) are highly interesting materials which are usable in a wide array of applications e.g. electrode materials for biosensors, lithium ion batteries, fuel cells and supercapacitors.*

In their paper “Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM” Wael Ali, Valbone Shabani, Matthias Linke, Sezin Sayin, Beate Gebert, Sedakat Altinpinar, Marcus Hildebrandt, Jochen S. Gutmann and Thomas Mayer-Gall present a study on the electrical properties of composite carbon nanofibres (CNFs) using current-sensitive atomic force microscopy (CS-AFM).*

This technique makes it possible to explore the electrical properties of single fibers and hence derive relationships between the structural features and the electrical properties.
NanoWorld AFM probes with conductive PtIr5 coated silicon tips (force constant 2.8 N m−1, length 240 μm, mean width 35 μm and a thickness of 3 μm, and tip height 10–15 μm) Arrow-EFM were used.*

The results presented in the paper show that the composite CNFs have a higher electrical conductivity than the neat CNFs and both the average diameter of the fibers and the electrical conductivity increase with an increasing AgNP content.*

Fig. 8 from “Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM “ by Wael Ali et al.: CS-AFM analysis of CNFs processed from PAN nanofibres electrospun with different concentrations. Images show the friction and current after both stabilisation (a) and carbonisation (b) processes. The applied bias voltage was +0.15 V. The scan area was 5 × 5 μm2 with a scale bar of 1 μm.

Fig. 8 from “Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM “ by Wael Ali et al.: CS-AFM analysis of CNFs processed from PAN nanofibres electrospun with different concentrations. Images show the friction and current after both stabilisation (a) and carbonisation (b) processes. The applied bias voltage was +0.15 V. The scan area was 5 × 5 μm2 with a scale bar of 1 μm.

*Wael Ali, Valbone Shabani, Matthias Linke, Sezin Sayin, Beate Gebert, Sedakat Altinpinar, Marcus Hildebrandt, Jochen S. Gutmann, Thomas Mayer-Gall
Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM
RSC Adv., 2019, 9, 4553-4562
DOI: 10.1039/C8RA04594A

Please follow this external link to the full article: https://pubs.rsc.org/en/content/articlehtml/2019/ra/c8ra04594a

Open Access: The article “Electrical conductivity of silver nanoparticle doped carbon nanofibres measured by CS-AFM” by Wael Ali, Valbone Shabani, Matthias Linke, Sezin Sayin, Beate Gebert, Sedakat Altinpinar, Marcus Hildebrandt, Jochen S. Gutmann and Thomas Mayer-Gall is licensed under a Creative Commons Attribution 3.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. To view a copy of this license, visit https://creativecommons.org/licenses/by/3.0/.

IgA tetramerization improves target breadth but not peak potency of functionality of anti-influenza virus broadly neutralizing antibody

Mucosal immunoglobulins comprise mainly secretory IgA antibodies (SIgAs), which are the major contributor to pathogen-specific immune responses in mucosal tissues. SIgAs exist as mainly dimers and tetramers and play critical roles in mucosal immune responses against influenza.*

Detailed characterization of these anti-viral SIgA is important for better understanding of the mechanisms underlying anti-viral immunity.*
In their article “IgA tetramerization improves target breadth but not peak potency of functionality of anti-influenza virus broadly neutralizing antibody” Saito S, Sano K, Suzuki T, Ainai A, Taga Y, Ueno T, et al. (2019) describe a means of generating a recombinant tetrameric monoclonal SIgA to enable exhaustive characterization of tetrameric SIgAs.
The tetrameric monoclonal SIgA possessing variable regions of anti-influenza viruses broadly neutralizing antibody show that tetramerization of SIgA improves target breadth, but not the peak potency, of their anti-viral functions.*
These results broaden the knowledge about the fundamental role of SIgA tetramerization in anti-viral humoral response at the human respiratory mucosa.*

The high speed atomic force microscopy ( HS-AFM ) experiments mentioned in the article were performed using a NanoWorld Ultra-Short Cantilever USC-F1.2-k0.15.

Fig 1. Production of recombinant tetrameric monoclonal SIgAs.

(A) Recombinant monoclonal IgA antibodies purified from the culture supernatant of cells co-transfected with A1+L (left upper), A1+L+J (left lower), A1+L+J+SC (right upper), or A2m2+L+J+SC (right lower), were subjected to size exclusion chromatography (SEC) analysis. A chromatogram showing absorbance at 280 nm revealed three major peaks: peak A (retention volume around 10.4 ml), peak B (retention volume around 9.3 ml), and peak C (retention volume around 8.4 ml). Data are representative of three independent experiments. (B) SDS-PAGE and BN-PAGE analysis of IgG and IgA1/IgA2m2 in each peak fraction (peak A, B, and C) purified from cells co-expressing SC (A1+L+J+SC or A2m2+L+J+SC). (C, D, E) High-mass MALDI-TOF MS analysis of the each peak fraction containing recombinant IgA1 purified from the culture supernatant of cells transfected with A1, L, J, and SC. (C) One main peak (arrow) corresponding to monomer (Mo) was detected in the peak A fraction. (D) Two main peaks (arrows) corresponding to a dimer (Di) and a di-cation dimer (Di2+) were detected in the peak B fraction. (E) Three main peaks (arrows) corresponding to a tetramer (Te), trimer (Tr), and di-cation tetramer (Te2+) were detected in the peak C fraction. (F, G) High-mass MALDI-TOF MS analysis of the each peak fraction of recombinant IgA2m2 purified from the culture supernatant from cells transfected with A2m2, L, J, and SC. (F) One main peak (arrow) corresponding to a monomer (Mo) was detected in the peak A fraction. (G) Three main peaks (arrows) corresponding to a tetramer (Te), a trimer (Tr), and a di-cation tetramer (Te2+) were detected in the peak C fraction. (H) Quantification of the amount of each subunit within the peak B or C fraction of recombinant SIgA1 or SIgA2m2 antibodies purified from the culture supernatant of cells transfected with A1/L/J,/SC or A2m2/L/J/SC using LC-MS with stable isotope-labeled standard peptides. The abundance of each subunit to that of J chain is expressed as a ratio. Data are expressed as box-and-whisker plot with minimum, maximum, median, upper and lower quartiles (n = 6–7). (I) HS-AFM image of peak C derived from a recombinant SIgA1 (A1Te) or SIgA2m2 (A2m2Te) antibody purified from the culture supernatant of cells transfected with A1/L/J/SC or A2m2/L/J/SC. Scale bar, 20 nm.

Fig 1. Production of recombinant tetrameric monoclonal SIgAs from ”
IgA tetramerization improves target breadth but not peak potency of functionality of anti-influenza virus broadly neutralizing antibody
” by
Saito S, Sano K, Suzuki T, Ainai A, Taga Y, Ueno T, et al. (2019) :
 
(A) Recombinant monoclonal IgA antibodies purified from the culture supernatant of cells co-transfected with A1+L (left upper), A1+L+J (left lower), A1+L+J+SC (right upper), or A2m2+L+J+SC (right lower), were subjected to size exclusion chromatography (SEC) analysis. A chromatogram showing absorbance at 280 nm revealed three major peaks: peak A (retention volume around 10.4 ml), peak B (retention volume around 9.3 ml), and peak C (retention volume around 8.4 ml). Data are representative of three independent experiments. (B) SDS-PAGE and BN-PAGE analysis of IgG and IgA1/IgA2m2 in each peak fraction (peak A, B, and C) purified from cells co-expressing SC (A1+L+J+SC or A2m2+L+J+SC). (C, D, E) High-mass MALDI-TOF MS analysis of the each peak fraction containing recombinant IgA1 purified from the culture supernatant of cells transfected with A1, L, J, and SC. (C) One main peak (arrow) corresponding to monomer (Mo) was detected in the peak A fraction. (D) Two main peaks (arrows) corresponding to a dimer (Di) and a di-cation dimer (Di2+) were detected in the peak B fraction. (E) Three main peaks (arrows) corresponding to a tetramer (Te), trimer (Tr), and di-cation tetramer (Te2+) were detected in the peak C fraction. (F, G) High-mass MALDI-TOF MS analysis of the each peak fraction of recombinant IgA2m2 purified from the culture supernatant from cells transfected with A2m2, L, J, and SC. (F) One main peak (arrow) corresponding to a monomer (Mo) was detected in the peak A fraction. (G) Three main peaks (arrows) corresponding to a tetramer (Te), a trimer (Tr), and a di-cation tetramer (Te2+) were detected in the peak C fraction. (H) Quantification of the amount of each subunit within the peak B or C fraction of recombinant SIgA1 or SIgA2m2 antibodies purified from the culture supernatant of cells transfected with A1/L/J,/SC or A2m2/L/J/SC using LC-MS with stable isotope-labeled standard peptides. The abundance of each subunit to that of J chain is expressed as a ratio. Data are expressed as box-and-whisker plot with minimum, maximum, median, upper and lower quartiles (n = 6–7). (I) HS-AFM image of peak C derived from a recombinant SIgA1 (A1Te) or SIgA2m2 (A2m2Te) antibody purified from the culture supernatant of cells transfected with A1/L/J/SC or A2m2/L/J/SC. Scale bar, 20 nm.

*Shinji Saito , Kaori Sano , Tadaki Suzuki , Akira Ainai, Yuki Taga,  Tomonori Ueno, Koshiro Tabata, Kumpei Saito, Yuji Wada, Yuki Ohara, Haruko Takeyama, Takato Odagiri, Tsutomu Kageyama, Kiyoko Ogawa-Goto, Pretty Multihartina, Vivi Setiawaty, Krisna Nur Andriana Pangesti, Hideki Hasegawa
IgA tetramerization improves target breadth but not peak potency of functionality of anti-influenza virus broadly neutralizing antibody
PLoS Pathog 15(1): e1007427.
DOI: https://doi.org/10.1371/journal.ppat.1007427

Please follow this external link for the full article: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1007427

Open Access: The article « IgA tetramerization improves target breadth but not peak potency of functionality of anti-influenza virus broadly neutralizing antibody » by Saito S, Sano K, Suzuki T, Ainai A, Taga Y, Ueno T, et al. (2019) is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.