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Cansu Tarakci E, Nihal Gevrek T. Isocyanate group containing reactive hydrogels: Facile synthesis and efficient biofunctionalization. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Grafting MSI-78A onto chitosan microspheres enhances its antimicrobial activity. Acta Biomater 2022; 137:186-198. [PMID: 34634508 DOI: 10.1016/j.actbio.2021.09.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/16/2021] [Accepted: 09/21/2021] [Indexed: 12/24/2022]
Abstract
MSI-78A (Pexiganan A) is one of the few antimicrobial peptides (AMPs) able to kill Helicobacter pylori, a pathogenic bacterium that colonizes the gastric mucosa of half of the world's population. Antibiotics fail in 20-40% of H. pylori-infected patients, reinforcing the need for alternative treatments. Herein, a bioengineered approach was developed. MSI-78A with a C-terminal cysteine was grafted onto chitosan microspheres (AMP-ChMic) by thiol-maleimide (Michael-addition) chemistry using a long heterobifunctional spacer (NHS-PEG113-MAL). Microspheres with ∼4 µm diameter (near H. pylori length) and stable at low pH were produced by spray drying using a chitosan solution with an incomplete genipin crosslinking. A 3 × 10-5 µg AMP/microsphere grafting was estimated/confirmed by UV/Vis and FTIR spectroscopies. AMP-ChMic were bactericidal against H. pylori J99 (highly pathogenic human strain) at lower concentrations than the free peptide (∼277 µg grafted MSI-78A-SH/mL vs 512 µg free MSI-78A-SH/mL), even after pre-incubation in simulated gastric conditions with pepsin. AMP-ChMic killed H. pylori by membrane destabilization and cytoplasm release in a ratio of ∼10 bacteria/microsphere. This can be attributed to H. pylori attraction to chitosan, facilitating the interaction of grafted AMP with bacterium membrane. Overall, it was demonstrated that the peptide-microsphere conjugation chemistry did not compromise the MSI-78A antimicrobial activity, instead it boosted its bactericidal performance against H. pylori. STATEMENT OF SIGNIFICANCE: Half of the world's population is infected with Helicobacter pylori, a gastric bacterium that is responsible for 90% of non-cardia gastric cancers. Therefore, H. pylori eradication is now advocated in all infected individuals. However, available antibiotic therapies fail in up to 40% patients. Antimicrobial peptides (AMPs) are appealing alternatives to antibiotics, but their high susceptibility in vivo limits their clinical translation. AMP immobilization onto biomaterials surface will overcome this problem. Herein, we demonstrate that immobilization of MSI-78A (one of the few AMPs with activity against H. pylori) onto chitosan microspheres (AMP-ChMic) enhances its anti-H. pylori activity even at acidic pH (gastric settings). These results highlight the strong potential of AMP-ChMic as an antibiotic alternative for H. pylori eradication.
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Hartmann RW, Pijnappel M, Nilvebrant J, Helgudottir HR, Asbjarnarson A, Traustadottir GA, Gudjonsson T, Nygren PÅ, Lehmann F, Odell LR. The Wittig bioconjugation of maleimide derived, water soluble phosphonium ylides to aldehyde-tagged proteins. Org Biomol Chem 2021; 19:10417-10423. [PMID: 34817496 DOI: 10.1039/d1ob01155c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we disclose the transformation of maleimides into water-soluble tris(2-carboxyethyl)phosphonium ylides and their subsequent application in the bioconjugation of protein- and peptide-linked aldehydes. The new entry into Wittig bioconjugate chemistry proceeds under mild conditions and relies on highly water soluble reagents, which are likely already part of most biochemists' inventory.
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Affiliation(s)
- Rafael W Hartmann
- Recipharm OT Chemistry, Virdings allé 16, 75450 Uppsala, Sweden.,Department of Medicinal Chemistry, Uppsala University, Uppsala Biomediciniska Centrum, Husargatan 3, 75123 Uppsala, Sweden.
| | | | - Johan Nilvebrant
- Department of Protein Science, Division of Protein Engineering, KTH School of Engineering Sciences in Chemistry, Biology and Health, AlbaNova Universitetscentrum, Roslagsvägen 30B, 10961 Stockholm, Sweden
| | - Hildur Run Helgudottir
- Stem Cell Research Unit, Biomedical Center, University of Iceland, 101 Reykjavik, Iceland
| | - Arni Asbjarnarson
- Stem Cell Research Unit, Biomedical Center, University of Iceland, 101 Reykjavik, Iceland
| | | | - Thorarinn Gudjonsson
- Stem Cell Research Unit, Biomedical Center, University of Iceland, 101 Reykjavik, Iceland.,Department of Laboratory Hematology, Landspítali-University Hospital, Reykjavik, Iceland
| | - Per-Åke Nygren
- Department of Protein Science, Division of Protein Engineering, KTH School of Engineering Sciences in Chemistry, Biology and Health, AlbaNova Universitetscentrum, Roslagsvägen 30B, 10961 Stockholm, Sweden
| | - Fredrik Lehmann
- Recipharm OT Chemistry, Virdings allé 16, 75450 Uppsala, Sweden
| | - Luke R Odell
- Department of Medicinal Chemistry, Uppsala University, Uppsala Biomediciniska Centrum, Husargatan 3, 75123 Uppsala, Sweden.
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A Fluidics-Based Biosensor to Detect and Characterize Inhibition Patterns of Organophosphate to Acetylcholinesterase in Food Materials. MICROMACHINES 2021; 12:mi12040397. [PMID: 33916863 PMCID: PMC8065683 DOI: 10.3390/mi12040397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 11/17/2022]
Abstract
A chip-based electrochemical biosensor is developed herein for the detection of organophosphate (OP) in food materials. The principle of the sensing platform is based on the inhibition of dimethoate (DMT), a typical OP that specifically inhibits acetylcholinesterase (AChE) activity. Carbon nanotube-modified gold electrodes functionalized with polydiallyldimethylammonium chloride (PDDA) and oxidized nanocellulose (NC) were investigated for the sensing of OP, yielding high sensitivity. Compared with noncovalent adsorption and deposition in bovine serum albumin, bioconjugation with lysine side chain activation allowed the enzyme to be stable over three weeks at room temperature. The total amount of AChE was quantified, whose activity inhibition was highly linear with respect to DMT concentration. Increased incubation times and/or DMT concentration decreased current flow. The composite electrode showed a sensitivity 4.8-times higher than that of the bare gold electrode. The biosensor was challenged with organophosphate-spiked food samples and showed a limit of detection (LOD) of DMT at 4.1 nM, with a limit of quantification (LOQ) at 12.6 nM, in the linear range of 10 nM to 1000 nM. Such performance infers significant potential for the use of this system in the detection of organophosphates in real samples.
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Blond P, Bevernaegie R, Troian-Gautier L, Lagrost C, Hubert J, Reniers F, Raussens V, Jabin I. Ready-to-Use Germanium Surfaces for the Development of FTIR-Based Biosensors for Proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12068-12076. [PMID: 33007158 DOI: 10.1021/acs.langmuir.0c02681] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Germanium is particularly suitable for the design of FTIR-based biosensors for proteins. The grafting of stable and thin organic layers on germanium surfaces remains, however, challenging. To tackle this problem, we developed a calix[4]arene-tetradiazonium salt decorated with four oligo(ethylene glycol) chains and a terminal reactive carboxyl group. This versatile molecular platform was covalently grafted on germanium surfaces to yield robust ready-to-use surfaces for biosensing applications. The grafted calixarene monolayer prevents nonspecific adsorption of proteins while allowing bioconjugation with biomolecules such as bovine serum albumin (BSA) or biotin. It is shown that the native form of the investigated proteins was maintained upon immobilization. As a proof of concept, the resulting calix[4]arene-based germanium biosensors were used through a combination of ATR-FTIR spectroscopy and fluorescence microscopy for the selective detection of streptavidin from a complex medium. This study opens real possibilities for the development of sensitive and selective FTIR-based biosensors devoted to the detection of proteins.
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Affiliation(s)
- Pascale Blond
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
- Laboratory for the Structure and Function of Biological Membranes, Centre for Structural Biology and Bioinformatics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, CP206/02, B-1050 Brussels, Belgium
| | - Robin Bevernaegie
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
| | - Ludovic Troian-Gautier
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
| | | | - Julie Hubert
- Chemistry of Surfaces, Interfaces and Nanomaterials, Université libre de Bruxelles (ULB), Boulevard du Triomphe, CP 255, B-1050 Brussels, Belgium
| | - François Reniers
- Chemistry of Surfaces, Interfaces and Nanomaterials, Université libre de Bruxelles (ULB), Boulevard du Triomphe, CP 255, B-1050 Brussels, Belgium
| | - Vincent Raussens
- Laboratory for the Structure and Function of Biological Membranes, Centre for Structural Biology and Bioinformatics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, CP206/02, B-1050 Brussels, Belgium
| | - Ivan Jabin
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
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Abstract
Infrared difference spectroscopy probes vibrational changes of proteins upon their perturbation. Compared with other spectroscopic methods, it stands out by its sensitivity to the protonation state, H-bonding, and the conformation of different groups in proteins, including the peptide backbone, amino acid side chains, internal water molecules, or cofactors. In particular, the detection of protonation and H-bonding changes in a time-resolved manner, not easily obtained by other techniques, is one of the most successful applications of IR difference spectroscopy. The present review deals with the use of perturbations designed to specifically change the protein between two (or more) functionally relevant states, a strategy often referred to as reaction-induced IR difference spectroscopy. In the first half of this contribution, I review the technique of reaction-induced IR difference spectroscopy of proteins, with special emphasis given to the preparation of suitable samples and their characterization, strategies for the perturbation of proteins, and methodologies for time-resolved measurements (from nanoseconds to minutes). The second half of this contribution focuses on the spectral interpretation. It starts by reviewing how changes in H-bonding, medium polarity, and vibrational coupling affect vibrational frequencies, intensities, and bandwidths. It is followed by band assignments, a crucial aspect mostly performed with the help of isotopic labeling and site-directed mutagenesis, and complemented by integration and interpretation of the results in the context of the studied protein, an aspect increasingly supported by spectral calculations. Selected examples from the literature, predominately but not exclusively from retinal proteins, are used to illustrate the topics covered in this review.
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Mittal V, Nedeljkovic M, Carpenter LG, Khokhar AZ, Chong HMH, Mashanovich GZ, Bartlett PN, Wilkinson JS. Waveguide Absorption Spectroscopy of Bovine Serum Albumin in the Mid-Infrared Fingerprint Region. ACS Sens 2019; 4:1749-1753. [PMID: 31264410 DOI: 10.1021/acssensors.9b00215] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein sensing in biological fluids provides important information to diagnose many clinically relevant diseases. Mid-infrared (MIR) absorption spectroscopy of bovine serum albumin (BSA) is experimentally demonstrated on a germanium on silicon (GOS) waveguide in the 1900-1000 cm-1 (5.3-10.0 μm) region of the MIR. GOS waveguides were shown to guide light up to a wavelength of 12.9 μm. The waveguide absorption spectrum of water, showing molecular bending vibrations, was obtained experimentally and compared with a theoretical model showing good agreement. Measurement of a concentration series of BSA protein in phosphate buffered saline (PBS) from 0.1 mg/mL to 100 mg/mL was performed on the waveguide using filter paper as a flow strip, and the amide I, II, and III peaks were observed and quantified.
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