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Fourier-transform infrared spectroscopy for monitoring proteolytic reactions using dry-films treated with trifluoroacetic acid. Sci Rep 2020; 10:7844. [PMID: 32398689 PMCID: PMC7217958 DOI: 10.1038/s41598-020-64583-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 04/16/2020] [Indexed: 12/15/2022] Open
Abstract
In this study we explore the potential of using Fourier-transform infrared (FTIR) spectra of trifluoroacetate-protein and peptide complexes for monitoring proteolytic reactions. The idea of treating dry-films of protein hydrolysates with trifluoroacetic acid (TFA) prior to FTIR analysis is based on the unique properties of TFA. By adding a large excess of TFA to protein hydrolysate samples, the possible protonation sites of the proteins and peptides will be saturated. In addition, TFA has a low boiling point when protonated as well as complex-forming abilities. When forming TFA-treated dry-films of protein hydrolysates, the excess TFA will evaporate and the deprotonated acid (CF3COO−) will interact as a counter ion with the positive charges on the sample materials. In the study, spectral changes in TFA-treated dry-films of protein hydrolysates from a pure protein and poultry by-products, were compared to the FTIR fingerprints of untreated dry-films. The results show that time-dependent information related to proteolytic reactions and, consequently, on the characteristics of the protein hydrolysates can be obtained. With additional developments, FTIR on dry-films treated with TFA may be regarded as a potential future tool for the analysis of all types of proteolytic reactions in the laboratory as well as in industry.
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Inoue K, Inasawa S. Positive and negative birefringence in packed films of binary spherical colloidal particles. RSC Adv 2020; 10:2566-2574. [PMID: 35496111 PMCID: PMC9048605 DOI: 10.1039/c9ra09704j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/06/2020] [Indexed: 12/20/2022] Open
Abstract
We have investigated the birefringence in packed films of binary spherical colloidal particles. Particulate films were obtained by drying a mixed suspension of colloidal particles with two different diameters. We observed positive and negative birefringence depending on the diameters and volume ratios of the large and small particles. When the diameters of the large and small particles were similar, the films showed positive birefringence. However, negative birefringence or weakening of positive birefringence was observed in films with a large diameter ratio and an optimal volume fraction of large particles. The large particles were embedded in packed small particles in the negative and weakened positive birefringent films. We propose a packing structure in which a single shell layer of small particles formed around a large particle. Using this model, we estimated the required volume ratio of large particles, and it was in good agreement with the optimal volume fraction. The relation between the packing structure of the binary colloidal particles and the birefringence is discussed. We have investigated the birefringence in packed films of binary spherical colloidal particles.![]()
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Affiliation(s)
- Kai Inoue
- Graduate School of Bio-Applications and Systems Engineering
- Tokyo University of Agriculture and Technology
- Koganei
- Japan
| | - Susumu Inasawa
- Graduate School of Bio-Applications and Systems Engineering
- Tokyo University of Agriculture and Technology
- Koganei
- Japan
- Department of Chemical Engineering
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Clancy KF, Dery S, Laforte V, Shetty P, Juncker D, Nicolau DV. Protein microarray spots are modulated by patterning method, surface chemistry and processing conditions. Biosens Bioelectron 2019; 130:397-407. [DOI: 10.1016/j.bios.2018.09.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 01/13/2023]
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Ederth T, Ekblad T. Swelling of Thin Poly(ethylene glycol)-Containing Hydrogel Films in Water Vapor-A Neutron Reflectivity Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5517-5526. [PMID: 29672068 DOI: 10.1021/acs.langmuir.8b00177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Hydrogels are widely used in biomedicine and for bioanalytical purposes, normally under wet conditions. For certain applications, processing steps, or process monitoring, hydrogel films are used or treated under ambient conditions, and because they are hygroscopic, it is of interest to investigate how they respond to changes in atmospheric humidity. We have used neutron reflectometry to follow the swelling of thin UV-polymerized hydrogel films in air under different relative humidities (RHs). These polymers were prepared to similar thicknesses on silica and gold substrates, and the chemical similarity between them was verified by infrared spectroscopy. The swelling in response to variations in RH was different for the layers on the two substrate types, reflecting structural changes induced by differences in the UV exposure required to achieve a given polymer thickness, as demonstrated also by differences in the Flory-Huggins interaction parameter, obtained by fitting a Flory-Huggins-type sorption model to the swelling data. Wetting studies show small changes in contact angles with surrounding humidity variations, indicating that structural reorganization at the interface in response to humidity changes is limited.
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Affiliation(s)
- Thomas Ederth
- Division of Molecular Physics, Department of Physics, Chemistry and Biology , Linköping University , SE-581 83 Linköping , Sweden
| | - Tobias Ekblad
- Division of Molecular Physics, Department of Physics, Chemistry and Biology , Linköping University , SE-581 83 Linköping , Sweden
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Chen Y, Xu LP, Meng J, Deng S, Ma L, Zhang S, Zhang X, Wang S. Superwettable microchips with improved spot homogeneity toward sensitive biosensing. Biosens Bioelectron 2018; 102:418-424. [DOI: 10.1016/j.bios.2017.11.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/26/2017] [Accepted: 11/09/2017] [Indexed: 01/05/2023]
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Suzuki S, Teramoto Y. Simple Inkjet Process To Fabricate Microstructures of Chitinous Nanocrystals for Cell Patterning. Biomacromolecules 2017; 18:1993-1999. [PMID: 28505423 DOI: 10.1021/acs.biomac.7b00527] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Structural polysaccharide nanocrystals (NCs) including cellulose nanocrystal have attracted attention. In order to broaden the range of application of the NCs, we can take advantage of their original characteristics by establishing simple and reasonable processing methods. We here demonstrate a micropatterning of animal cellular adhesion by inkjet printing of aqueous dispersions of cytocompatible chitinous NCs onto cellophane films. We display how to regulate the deposition form and two-dimensional shape of the chitinous NC micromoldings using a research inkjet printer. Adhesive capability of mouse fibroblasts onto the chitinous substrates was greatly improved by alkali deacetylation. The deacetylated products remained rod-like nanostructures, but the original chitin crystal form changed to that of chitosan by an intensive deacetylation. The adhered cells could be recovered glycolytically. The chitinous micropatterning substrates can be utilized for biomedical applications such as controlling of cellular shapes, precise monitoring molecular events in biochemistry, and drug screening.
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Affiliation(s)
- Shuntaro Suzuki
- Department of Applied Life Science, Faculty of Applied Biological Sciences, and ‡Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University , Gifu 501-1193, Japan
| | - Yoshikuni Teramoto
- Department of Applied Life Science, Faculty of Applied Biological Sciences, and ‡Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University , Gifu 501-1193, Japan
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Devineau S, Anyfantakis M, Marichal L, Kiger L, Morel M, Rudiuk S, Baigl D. Protein Adsorption and Reorganization on Nanoparticles Probed by the Coffee-Ring Effect: Application to Single Point Mutation Detection. J Am Chem Soc 2016; 138:11623-32. [DOI: 10.1021/jacs.6b04833] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Stéphanie Devineau
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department
of Chemistry, PASTEUR, 24 rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Manos Anyfantakis
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department
of Chemistry, PASTEUR, 24 rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Laurent Marichal
- LIONS, NIMBE,
CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette, France
| | - Laurent Kiger
- IMRB-INSERM U955, 5 rue Gustave Eiffel, 94017 Creteil Cedex, France
| | - Mathieu Morel
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department
of Chemistry, PASTEUR, 24 rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Sergii Rudiuk
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department
of Chemistry, PASTEUR, 24 rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Damien Baigl
- Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department
of Chemistry, PASTEUR, 24 rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris, France
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Abstract
BACKGROUND Inhomogeneous sample distribution in DBS is a problem for accurate quantitative analysis of DBS, and has often been explained by chromatographic effects. RESULTS We present a model describing formation of inhomogeneous DBS during drying of the spot caused by higher evaporation rates of water at the edge as compared with the center. Color intensity analysis shows that the relative humidity and DBS card position affect the homogeneity of DBS. CONCLUSION The so-called 'coffee-stain effect' explains the typical distribution pattern of analytes with higher concentrations measured along the edge of DBS as compared with the center. The driving mechanism and potential influencing factors should be considered when addressing the inhomogeneity of DBS in the future.
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