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Dutta A, Ončák M, Izadi F, Arthur-Baidoo E, Ameixa J, Denifl S, Bald I. Plasmon-driven chemical transformation of a secondary amide probed by surface enhanced Raman scattering. Commun Chem 2024; 7:188. [PMID: 39187571 PMCID: PMC11347659 DOI: 10.1038/s42004-024-01276-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 08/14/2024] [Indexed: 08/28/2024] Open
Abstract
Plasmon-driven chemical conversion is gaining burgeoning interest in the field of heterogeneous catalysis. Herein, we study the reactivity of N-methyl-4-sulfanylbenzamide (NMSB) at nanocavities of gold and silver nanoparticle aggregates under plasmonic excitation to gain understanding of the respective reaction mechanism. NMSB is a secondary amide, which is a frequent binding motive found in peptides and a common coupling product of organic molecules and biomolecules. Surface-enhanced Raman scattering (SERS) is used as a two-in-one in-situ spectroscopic tool to initiate the molecular transformation process and simultaneously monitor and analyze the reaction products. Supported by dissociative electron attachment (DEA) studies with the gas phase molecule, a hot electron-mediated conversion of NMSB to p-mercaptobenzamide and p-mercaptobenzonitrile is proposed at the plasmonic nanocavities. The reaction rate showed negligible dependence on the external temperature, ruling out the dominant role of heat in the chemical transformation at the plasmonic interface. This is reflected in the absence of a superlinear relationship between the reaction rate constant and the laser power density, and DEA and SERS studies indicate a hot-electron mediated pathway. We conclude that the overall reaction rate is limited by the availability of energetic hot electrons to the NMSB molecule.
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Affiliation(s)
- Anushree Dutta
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Farhad Izadi
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Eugene Arthur-Baidoo
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - João Ameixa
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Ilko Bald
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, Prague, 18223, Czech Republic.
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2
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Guler A, Yilmaz A, Oncer N, Sever NI, Cengiz Sahin S, Kavakcıoglu Yardimci B, Yilmaz M. Machine learning-assisted SERS approach enables the biochemical discrimination in Bcl-2 and Mcl-1 expressing yeast cells treated with ketoconazole and fluconazole antifungals. Talanta 2024; 276:126248. [PMID: 38776770 DOI: 10.1016/j.talanta.2024.126248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 05/01/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Antifungal medications are important due to their potential application in cancer treatment either on their own or with traditional treatments. The mechanisms that prevent the effects of these medications and restrict their usage in cancer treatment are not completely understood. The evaluation and discrimination of the possible protective effects of the anti-apoptotic members of the Bcl-2 family of proteins, critical regulators of mitochondrial apoptosis, against antifungal drug-induced cell death has still scientific uncertainties that must be considered. Novel, simple, and reliable strategies are highly demanded to identify the biochemical signature of this phenomenon. However, the complex nature of cells poses challenges for the analysis of cellular biochemical changes or classification. In this study, for the first time, we investigated the probable protective activities of Bcl-2 and Mcl-1 proteins against cell damage induced by ketoconazole (KET) and fluconazole (FLU) antifungal drugs in a yeast model through surface-enhanced Raman spectroscopy (SERS) approach. The proposed SERS platform created robust Raman spectra with a high signal-to-noise ratio. The analysis of SERS spectral data via advanced unsupervised and supervised machine learning methods enabled unquestionable differentiation (100 %) in samples and biomolecular identification. Various SERS bands related to lipids and proteins observed in the analyses suggest that the expression of these anti-apoptotic proteins reduces oxidative biomolecule damage induced by the antifungals. Also, cell viability assay, Annexin V-FITC/PI double staining, and total oxidant and antioxidant status analyses were performed to support Raman measurements. We strongly believe that the proposed approach paves the way for the evaluation of various biochemical structures/changes in various cells.
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Affiliation(s)
- Ayşenur Guler
- Chemistry Department, Graduate School of Natural and Applied Sciences, Pamukkale University, Denizli, Turkey
| | - Asli Yilmaz
- Department of Molecular Biology & Genetics, Faculty of Science, Ataturk University, Erzurum, Turkey
| | - Nazli Oncer
- Department of Nanoscience and Nanoengineering, Graduate School of Natural and Applied Sciences, Ataturk University, Erzurum, Turkey
| | - Nurettin Ilter Sever
- Department of Molecular Biology & Genetics, Faculty of Science, Pamukkale University, Denizli, Turkey
| | - Sevilay Cengiz Sahin
- Department of Molecular Biology & Genetics, Faculty of Science, Pamukkale University, Denizli, Turkey
| | - Berna Kavakcıoglu Yardimci
- Department of Chemistry, Faculty of Science, Pamukkale University, Denizli, Turkey; Advanced Technology Application and Research Center, Pamukkale University, Denizli, Turkey.
| | - Mehmet Yilmaz
- Department of Nanoscience and Nanoengineering, Graduate School of Natural and Applied Sciences, Ataturk University, Erzurum, Turkey; Department of Chemical Engineering, Faculty of Engineering, Ataturk University, Erzurum, Turkey.
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3
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Öberg R, Sil TB, Johansson AC, Malyshev D, Landström L, Johansson S, Andersson M, Andersson PO. UV-Induced Spectral and Morphological Changes in Bacterial Spores for Inactivation Assessment. J Phys Chem B 2024; 128:1638-1646. [PMID: 38326108 PMCID: PMC10895659 DOI: 10.1021/acs.jpcb.3c07062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
The ability to detect and inactivate spore-forming bacteria is of significance within, for example, industrial, healthcare, and defense sectors. Not only are stringent protocols necessary for the inactivation of spores but robust procedures are also required to detect viable spores after an inactivation assay to evaluate the procedure's success. UV radiation is a standard procedure to inactivate spores. However, there is limited understanding regarding its impact on spores' spectral and morphological characteristics. A further insight into these UV-induced changes can significantly improve the design of spore decontamination procedures and verification assays. This work investigates the spectral and morphological changes to Bacillus thuringiensis spores after UV exposure. Using absorbance and fluorescence spectroscopy, we observe an exponential decay in the spectral intensity of amino acids and protein structures, as well as a logistic increase in dimerized DPA with increased UV exposure on bulk spore suspensions. Additionally, using micro-Raman spectroscopy, we observe DPA release and protein degradation with increased UV exposure. More specifically, the protein backbone's 1600-1700 cm-1 amide I band decays slower than other amino acid-based structures. Last, using electron microscopy and light scattering measurements, we observe shriveling of the spore bodies with increased UV radiation, alongside the leaking of core content and disruption of proteinaceous coat and exosporium layers. Overall, this work utilized spectroscopy and electron microscopy techniques to gain new understanding of UV-induced spore inactivation relating to spore degradation and CaDPA release. The study also identified spectroscopic indicators that can be used to determine spore viability after inactivation. These findings have practical applications in the development of new spore decontamination and inactivation validation methods.
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Affiliation(s)
- Rasmus Öberg
- Swedish
Defence Research Agency (FOI), Umeå 90621, Sweden
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | - Timir B. Sil
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | | | | | - Lars Landström
- Swedish
Defence Research Agency (FOI), Norra Sorunda 13794, Sweden
| | | | - Magnus Andersson
- Department
of Physics, Umeå University, Umeå 90736, Sweden
- Umeå
Centre for Microbial Research (UCMR), Umeå 90736, Sweden
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4
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Lomboni DJ, Ozgun A, de Medeiros TV, Staines W, Naccache R, Woulfe J, Variola F. Electroconductive Collagen-Carbon Nanodots Nanocomposite Elicits Neurite Outgrowth, Supports Neurogenic Differentiation and Accelerates Electrophysiological Maturation of Neural Progenitor Spheroids. Adv Healthc Mater 2024; 13:e2301894. [PMID: 37922888 DOI: 10.1002/adhm.202301894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/04/2023] [Indexed: 11/07/2023]
Abstract
Neuronal disorders are characterized by the loss of functional neurons and disrupted neuroanatomical connectivity, severely impacting the quality of life of patients. This study investigates a novel electroconductive nanocomposite consisting of glycine-derived carbon nanodots (GlyCNDs) incorporated into a collagen matrix and validates its beneficial physicochemical and electro-active cueing to relevant cells. To this end, this work employs mouse induced pluripotent stem cell (iPSC)-derived neural progenitor (NP) spheroids. The findings reveal that the nanocomposite markedly augmented neuronal differentiation in NP spheroids and stimulate neuritogenesis. In addition, this work demonstrates that the biomaterial-driven enhancements of the cellular response ultimately contribute to the development of highly integrated and functional neural networks. Lastly, acute dizocilpine (MK-801) treatment provides new evidence for a direct interaction between collagen-bound GlyCNDs and postsynaptic N-methyl-D-aspartate (NMDA) receptors, thereby suggesting a potential mechanism underlying the observed cellular events. In summary, the findings establish a foundation for the development of a new nanocomposite resulting from the integration of carbon nanomaterials within a clinically approved hydrogel, toward an effective biomaterial-based strategy for addressing neuronal disorders by restoring damaged/lost neurons and supporting the reestablishment of neuroanatomical connectivity.
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Affiliation(s)
- David J Lomboni
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
- Ottawa-Carleton Institute for Biomedical Engineering (OCIBME), Ottawa, ON, K1N 6N5, Canada
| | - Alp Ozgun
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Tayline V de Medeiros
- Department of Chemistry and Biochemistry and the Centre for NanoScience Research, Concordia University, Montreal, QC, H4B 1R6, Canada
- Quebec Centre for Advanced Materials, Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - William Staines
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Rafik Naccache
- Department of Chemistry and Biochemistry and the Centre for NanoScience Research, Concordia University, Montreal, QC, H4B 1R6, Canada
- Quebec Centre for Advanced Materials, Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - John Woulfe
- The Ottawa Hospital Research Institute, Ottawa, ON, K1Y 4E9, Canada
| | - Fabio Variola
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
- Ottawa-Carleton Institute for Biomedical Engineering (OCIBME), Ottawa, ON, K1N 6N5, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
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5
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Mastrangelo R, Okada T, Ogura T, Ogura T, Baglioni P. Direct observation of the effects of chemical fixation in MNT-1 cells: A SE-ADM and Raman study. Proc Natl Acad Sci U S A 2023; 120:e2308088120. [PMID: 38091295 PMCID: PMC10743460 DOI: 10.1073/pnas.2308088120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 10/16/2023] [Indexed: 12/18/2023] Open
Abstract
Aldehydes fixation was accidentally discovered in the early 20th century and soon became a widely adopted practice in the histological field, due to an excellent staining enhancement in tissues imaging. However, the fixation process itself entails cell proteins denaturation and crosslinking. The possible presence of artifacts, that depends on the specific system under observation, must therefore be considered to avoid data misinterpretation. This contribution takes advantage of scanning electron assisted-dielectric microscopy (SE-ADM) and Raman 2D imaging to reveal the possible presence and the nature of artifacts in unstained, and paraformldehyde, PFA, fixed MNT-1 cells. The high resolution of the innovative SE-ADM technique allowed the identification of globular protein clusters in the cell cytoplasm, formed after protein denaturation and crosslinking. Concurrently, SE-ADM images showed a preferential melanosome adsorption on the cluster's outer surface. The micron-sized aggregates were discernible in Raman 2D images, as the melanosomes signal, extracted through 2D principal component analysis, unequivocally mapped their location and distribution within the cells, appearing randomly distributed in the cytoplasm. Protein clusters were not observed in living MNT-1 cells. In this case, mature melanosomes accumulate preferentially at the cell periphery and are more closely packed than in fixed cells. Our results show that, although PFA does not affect the melanin structure, it disrupts melanosome distribution within the cells. Proteins secondary structure, conversely, is partially lost, as shown by the Raman signals related to α-helix, β-sheets, and specific amino acids that significantly decrease after the PFA treatment.
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Affiliation(s)
- Rosangela Mastrangelo
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba305-8566, Japan
- NIKKOL GROUP Nikko Chemicals Co., Ltd., Tokyo174-0046, Japan
- Department of Chemistry and Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (Center for Colloid and Surface Science), University of Florence, FlorenceI-50019, Italy
| | - Tomoko Okada
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba305-8566, Japan
| | - Taku Ogura
- NIKKOL GROUP Nikko Chemicals Co., Ltd., Tokyo174-0046, Japan
| | - Toshihiko Ogura
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba305-8566, Japan
| | - Piero Baglioni
- Department of Chemistry and Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (Center for Colloid and Surface Science), University of Florence, FlorenceI-50019, Italy
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6
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Zdaniauskienė A, Talaikis M, Charkova T, Sadzevičienė R, Labanauskas L, Niaura G. Electrochemical Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy of Imidazole Ring Functionalized Monolayer on Smooth Gold Electrode. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27196531. [PMID: 36235068 PMCID: PMC9573715 DOI: 10.3390/molecules27196531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022]
Abstract
The imidazole ring (Im) of histidine side chains plays a unique role in the function of proteins through covalent bonding with metal ions and hydrogen bonding interactions with adjusted biomolecules and water. At biological interfaces, these interactions are modified because of the presence of an electric field. Self-assembled monolayers (SAMs) with the functional Im group mimic the histidine side chain at electrified interfaces. In this study, we applied in-situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) to probe the structure and hydrogen bonding of Im-functionalized SAM on smooth Au at the electrochemical interface. The self-assembly of molecules on the Au induced the proton shift from N1 atom (Tautomer-I), which is the dominant form of Im in the bulk sample, to N3 atom (Tautomer-II). The impact of electrode potential on the hydrogen bonding interaction strength of the Im ring was identified by SHINERS. Temperature-Raman measurements and density functional theory (DFT) analysis revealed the spectral marker for Im ring packing (mode near 1496-1480 cm-1) that allowed us to associate the confined and strongly hydrogen bonded interfacial Im groups with electrode polarization at -0.8 V. Reflection adsorption IR (RAIR) spectra of SAMs with and without Im revealed that the bulky ring prevented the formation of a strongly hydrogen bonded amide group network.
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Affiliation(s)
- Agnė Zdaniauskienė
- Center for Physical Sciences and Technology (FTMC), Department of Organic Chemistry, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Martynas Talaikis
- Life Sciences Center, Institute of Biochemistry, Department of Bioelectrochemistry and Biospectroscopy, Vilnius University, Sauletekio Ave. 7, LT-10257 Vilnius, Lithuania
- Correspondence: (M.T.); (G.N.)
| | - Tatjana Charkova
- Center for Physical Sciences and Technology (FTMC), Department of Organic Chemistry, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Rita Sadzevičienė
- Center for Physical Sciences and Technology (FTMC), Department of Organic Chemistry, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Linas Labanauskas
- Center for Physical Sciences and Technology (FTMC), Department of Organic Chemistry, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Gediminas Niaura
- Center for Physical Sciences and Technology (FTMC), Department of Organic Chemistry, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania
- Life Sciences Center, Institute of Biochemistry, Department of Bioelectrochemistry and Biospectroscopy, Vilnius University, Sauletekio Ave. 7, LT-10257 Vilnius, Lithuania
- Correspondence: (M.T.); (G.N.)
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7
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Guan H, Huang C, Lu D, Chen G, Lin J, Hu J, He Y, Huang Z. Label-free Raman spectroscopy: A potential tool for early diagnosis of diabetic keratopathy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 256:119731. [PMID: 33819764 DOI: 10.1016/j.saa.2021.119731] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Diabetes has become a major public health problem worldwide, and the incidence of diabetes has been increasing progressively. Diabetes is prone to cause various complications, among which diabetic keratopathy (DK) emphasizes the significant impact on the cornea. The current diagnosis of DK lacks biochemical markers that can be used for early and non-invasive screening and detection. In contrast, in this study, Raman spectroscopy, which demonstrates non-destructive, label-free features, especially the unique advantage of providing molecular fingerprint information for target substances, were utilized to interrogate the intrinsic information of the corneal tissues from normal and diabetic mouse models, respectively. Visually, the Raman spectral response derived from the biochemical components and biochemical differences between the two groups were compared. Moreover, multivariate analysis methods such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were carried out for advanced statistical analysis. PCA yields a diagnostic results of 57.4% sensitivity, 89.2% specificity, 74.8% accuracy between the diabetic group and control group; Moreover, PLS-DA was employed to enhance the diagnostic ability, showing 76.1% sensitivity, 86.1% specificity, and 87.6% accuracy between the diabetic group and control group. Our proof-of-concept results show the potential of Raman spectroscopy-based techniques to help explore the underlying pathogenesis of DK disease and thus be further expanded for potential applications in the early screening of diabetic diseases.
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Affiliation(s)
- Haohao Guan
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Chunyan Huang
- Department of Ophthalmology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Dechan Lu
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Guannan Chen
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Juqiang Lin
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Jianzhang Hu
- Department of Ophthalmology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Youwu He
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Zufang Huang
- Key Laboratory of Opto-Electronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, China.
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8
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Ternary biogenic silica/magnetite/graphene oxide composite for the hyperactivation of Candida rugosa lipase in the esterification production of ethyl valerate. Enzyme Microb Technol 2021; 148:109807. [PMID: 34116744 DOI: 10.1016/j.enzmictec.2021.109807] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 02/07/2023]
Abstract
Oil palm leaves (OPL) silica (SiO2) can replace the energy-intensive, commercially produced SiO2. Moreover, the agronomically sourced biogenic SiO2 is more biocompatible and cost-effective enzyme support, which properties could be improved by the addition of magnetite (Fe3O4) and graphene oxide (GO) to yield better ternary support to immobilize enzymes, i.e., Candida rugosa lipase (CRL). This study aimed to optimize the Candida rugosa lipase (CRL immobilization onto the ternary OPL-silica-magnetite (Fe3O4)-GO (SiO2/Fe3O4/GO) support, for use as biocatalyst for ethyl valerate (EV) production. Notably, this is the first study detailing the CRL/SiO2/Fe3O4/GO biocatalyst preparation for rapid and high yield production of ethyl valerate (EV). AFM and FESEM micrographs revealed globules of CRL covalently bound to GL-A-SiO2/Fe3O4/GO; similar to Raman and UV-spectroscopy results. FTIR spectra revealed amide bonds at 3478 cm-1 and 1640 cm-1 from covalent interactions between CRL and GL-A-SiO2/Fe3O4/GO. Optimum immobilization conditions were 4% (v/v) glutaraldehyde, 8 mg/mL CRL, at 16 h stirring in 150 mM NaCl at 30 °C, offering 24.78 ± 0.26 mg/g protein (specific activity = 65.24 ± 0.88 U/g). The CRL/SiO2/Fe3O4/GO yielded 77.43 ± 1.04 % of EV compared to free CRL (48.75 ± 0.70 %), verifying the suitability of SiO2/Fe3O4/GO to hyperactivate and stabilize CRL for satisfactory EV production.
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9
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Reflection Absorption Infrared Spectroscopy Characterization of SAM Formation from 8-Mercapto- N-(phenethyl)octanamide Thiols with Phe Ring and Amide Groups. Molecules 2020; 25:molecules25235633. [PMID: 33265984 PMCID: PMC7730404 DOI: 10.3390/molecules25235633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/20/2020] [Accepted: 11/27/2020] [Indexed: 11/17/2022] Open
Abstract
Multifunctional amide-containing self-assembled monolayers (SAMs) provide prospects for the construction of interfaces with required physicochemical properties and distinctive stability. In this study, we report the synthesis of amide-containing thiols with terminal phenylalanine (Phe) ring functionality (HS(CH2)7CONH(CH2)2C6H5) and the characterization of the formation of SAMs from these thiols on gold by reflection absorption infrared spectroscopy (RAIRS). For reliable assignments of vibrational bands, ring deuterated analogs were synthesized and studied as well. Adsorption time induced changes in Amide-II band frequency and relative intensity of Amide-II/Amide-I bands revealed two-state sigmoidal form dependence with a transition inflection points at 2.2 ± 0.5 and 4.7 ± 0.5 min, respectively. The transition from initial (disordered) to final (hydrogen-bonded, ordered) structure resulted in increased Amide-II frequency from 1548 to 1557 cm-1, which is diagnostic for a strongly hydrogen-bonded amide network in trans conformation. However, the lateral interactions between the alkyl chains were found to be somewhat reduced when compared with well-ordered alkane thiol monolayers.
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