β‐Sheets Orientation in Physisorbed Protein Layers
Abstract Physisorption of antibodies onto surfaces is a low‐cost, rapid, and effective approach for immobilizing bioreceptors in applications such as bioelectronic sensors. However, there is a prevailing notion that physisorbed protein layers lack structural order, thus potentially compromising thei...
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2025-03-01
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| Series: | Advanced Materials Interfaces |
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| Online Access: | https://doi.org/10.1002/admi.202400867 |
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| author | Matteo Piscitelli Diellza Bajrami Cinzia Di Franco Lucia Sarcina Michele Catacchio Eleonora Macchia Luisa Torsi Boris Mizaikoff Gaetano Scamarcio |
| author_facet | Matteo Piscitelli Diellza Bajrami Cinzia Di Franco Lucia Sarcina Michele Catacchio Eleonora Macchia Luisa Torsi Boris Mizaikoff Gaetano Scamarcio |
| author_sort | Matteo Piscitelli |
| collection | DOAJ |
| description | Abstract Physisorption of antibodies onto surfaces is a low‐cost, rapid, and effective approach for immobilizing bioreceptors in applications such as bioelectronic sensors. However, there is a prevailing notion that physisorbed protein layers lack structural order, thus potentially compromising their stability and sensitivity compared to antibody films that are covalently attached to the substrate surface. This study demonstrates the preferential orientation of β‐sheets within the secondary structure of protein layers, specifically anti‐immunoglobulin G (anti‐IgG) and bovine serum albumin (BSA), when physisorbed onto gold (Au) thin films. Using polarization modulation infrared reflection‐absorption spectroscopy (PM‐IRRAS) and infrared attenuated total reflection (IR‐ATR) spectroscopy, it has been confirmed that the β‐strands in these protein layers are tilted relative to the surface normal by average angles of 75.3° ± 0.4° for anti‐IgG and of 79.3 ± 0.2° for BSA. These results are obtained by analyzing the orientation of the transition dipole moments (TDMs) associated with the amide I molecular vibrations derived from a comparison between experimental and simulated mid‐infrared spectra assuming isotropically oriented TDMs. The simulations incorporate refractive and absorption index dispersions obtained from the IR‐ATR spectra. Thus obtained findings offer valuable molecular‐level insights facilitating the design and optimization of biofunctionalized interfaces in advanced biomedical and biosensing applications. |
| format | Article |
| id | doaj-art-059dfd1c3e98494081d1091009492fe5 |
| institution | Kabale University |
| issn | 2196-7350 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Advanced Materials Interfaces |
| spelling | doaj-art-059dfd1c3e98494081d1091009492fe52025-08-20T03:41:46ZengWiley-VCHAdvanced Materials Interfaces2196-73502025-03-01126n/an/a10.1002/admi.202400867β‐Sheets Orientation in Physisorbed Protein LayersMatteo Piscitelli0Diellza Bajrami1Cinzia Di Franco2Lucia Sarcina3Michele Catacchio4Eleonora Macchia5Luisa Torsi6Boris Mizaikoff7Gaetano Scamarcio8Dipartimento Interateneo di Fisica Università degli Studi di Bari Aldo Moro Bari 70125 ItalyInstitute of Analytical and Bioanalytical Chemistry Ulm University Albert Einstein‐Allee 11 89081 Ulm GermanyConsiglio Nazionale delle Ricerche – Istituto di Fotonica e Nanotecnologie CNR‐IFN Bari 70126 ItalyDipartimento di Chimica Università degli Studi di Bari Aldo Moro Bari 70125 ItalyDipartimento di Farmacia‐Scienze del Farmaco Università degli Studi di Bari Aldo Moro Bari 70125 ItalyDipartimento di Farmacia‐Scienze del Farmaco Università degli Studi di Bari Aldo Moro Bari 70125 ItalyDipartimento di Chimica Università degli Studi di Bari Aldo Moro Bari 70125 ItalyInstitute of Analytical and Bioanalytical Chemistry Ulm University Albert Einstein‐Allee 11 89081 Ulm GermanyCNR Istituto Nanoscienze c/o NEST Scuola Normale Superiore Piazza San Silvestro 12 Pisa 56127 ItalyAbstract Physisorption of antibodies onto surfaces is a low‐cost, rapid, and effective approach for immobilizing bioreceptors in applications such as bioelectronic sensors. However, there is a prevailing notion that physisorbed protein layers lack structural order, thus potentially compromising their stability and sensitivity compared to antibody films that are covalently attached to the substrate surface. This study demonstrates the preferential orientation of β‐sheets within the secondary structure of protein layers, specifically anti‐immunoglobulin G (anti‐IgG) and bovine serum albumin (BSA), when physisorbed onto gold (Au) thin films. Using polarization modulation infrared reflection‐absorption spectroscopy (PM‐IRRAS) and infrared attenuated total reflection (IR‐ATR) spectroscopy, it has been confirmed that the β‐strands in these protein layers are tilted relative to the surface normal by average angles of 75.3° ± 0.4° for anti‐IgG and of 79.3 ± 0.2° for BSA. These results are obtained by analyzing the orientation of the transition dipole moments (TDMs) associated with the amide I molecular vibrations derived from a comparison between experimental and simulated mid‐infrared spectra assuming isotropically oriented TDMs. The simulations incorporate refractive and absorption index dispersions obtained from the IR‐ATR spectra. Thus obtained findings offer valuable molecular‐level insights facilitating the design and optimization of biofunctionalized interfaces in advanced biomedical and biosensing applications.https://doi.org/10.1002/admi.202400867β‐sheetinfrared attenuated total reflection spectroscopymolecular orientationprotein layerspolarization modulation infrared reflection absorption spectroscopy |
| spellingShingle | Matteo Piscitelli Diellza Bajrami Cinzia Di Franco Lucia Sarcina Michele Catacchio Eleonora Macchia Luisa Torsi Boris Mizaikoff Gaetano Scamarcio β‐Sheets Orientation in Physisorbed Protein Layers Advanced Materials Interfaces β‐sheet infrared attenuated total reflection spectroscopy molecular orientation protein layers polarization modulation infrared reflection absorption spectroscopy |
| title | β‐Sheets Orientation in Physisorbed Protein Layers |
| title_full | β‐Sheets Orientation in Physisorbed Protein Layers |
| title_fullStr | β‐Sheets Orientation in Physisorbed Protein Layers |
| title_full_unstemmed | β‐Sheets Orientation in Physisorbed Protein Layers |
| title_short | β‐Sheets Orientation in Physisorbed Protein Layers |
| title_sort | β sheets orientation in physisorbed protein layers |
| topic | β‐sheet infrared attenuated total reflection spectroscopy molecular orientation protein layers polarization modulation infrared reflection absorption spectroscopy |
| url | https://doi.org/10.1002/admi.202400867 |
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