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Edgar M, Kuhn S, Page G, Grootveld M. Computational simulation of 1 H NMR profiles of complex biofluid analyte mixtures at differential operating frequencies: Applications to low-field benchtop spectra. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:1097-1112. [PMID: 34847251 DOI: 10.1002/mrc.5236] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/30/2021] [Accepted: 11/23/2021] [Indexed: 06/13/2023]
Abstract
Estimations of accurate and reliable NMR chemical shift values, coupling patterns and constants within a reasonable timeframe remain significantly challenging, and the unavailability of reliable software strategies for the prediction of low-field (e.g., 60 MHz) spectra from those acquired at higher operating frequencies hampers their direct comparison. Hence, this study explored the applications of accessible software options for predicting these parameters in the 1 H NMR profiles of analytes as a function of magnetic field strength; this was performed for individual analytes and also for complex biofluid matrices featured in metabolomics investigations. For this purpose, results from the very first successful experimental acquisition and simulation of the 1 H NMR profiles of intact human salivary supernatant samples on a 60 MHz benchtop spectrometer were evaluated. Using salivary metabolite concentrations determined at 400 MHz, it was demonstrated that simulation of the low-field spectra of five biomolecules with the most prominent 1 H resonances detectable allowed multiple component fits to be applied to experimental spectra. Hence, these salivary 1 H NMR profiles could be successfully predicted throughout the 45-600 MHz operating frequency range. With the exception of propionate resonance multiplets, which revealed more complex coupling patterns at low field and required more astute computational and fitting options, valuable quantitative metabolomics data on salivary acetate, formate, methanol and glycine could be attained from low-field spectrometres. These studies are both timely and pertinent in view of the recent advancement of low-field benchtop NMR facilities for diagnostically significant biomarker tracking in biofluids. Experiments performed with added ammonium chloride to facilitate the release of salivary metabolites from biopolymer binding sites provided evidence that a small but nevertheless significant proportion of propionate, but not lactate, was bound to such sites, an observation of much relevance to biomolecule quantification in salivary metabolomics investigations.
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Affiliation(s)
- Mark Edgar
- Department of Chemistry, University of Loughborough, Loughborough, UK
| | - Stefan Kuhn
- School of Computer Science and Informatics, De Montfort University, Leicester, UK
| | - Georgina Page
- Leicester School of Pharmacy, De Montfort University, Leicester, UK
| | - Martin Grootveld
- Leicester School of Pharmacy, De Montfort University, Leicester, UK
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Bonetti L, Fiorati A, D’Agostino A, Pelacani CM, Chiesa R, Farè S, De Nardo L. Smart Methylcellulose Hydrogels for pH-Triggered Delivery of Silver Nanoparticles. Gels 2022; 8:298. [PMID: 35621596 PMCID: PMC9140787 DOI: 10.3390/gels8050298] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/05/2022] [Accepted: 05/10/2022] [Indexed: 02/01/2023] Open
Abstract
Infection is a severe complication in chronic wounds, often leading to morbidity or mortality. Current treatments rely on dressings, which frequently contain silver as a broad-spectrum antibacterial agent, although improper dosing can result in severe side effects. This work proposes a novel methylcellulose (MC)-based hydrogel designed for the topical release of silver nanoparticles (AgNPs) via an intelligent mechanism activated by the pH variations in infected wounds. A preliminary optimization of the physicochemical and rheological properties of MC hydrogels allowed defining the optimal processing conditions in terms of crosslinker (citric acid) concentration, crosslinking time, and temperature. MC/AgNPs nanocomposite hydrogels were obtained via an in situ synthesis process, exploiting MC both as a capping and reducing agent. AgNPs with a 12.2 ± 2.8 nm diameter were obtained. MC hydrogels showed a dependence of the swelling and degradation behavior on both pH and temperature and a noteworthy pH-triggered release of AgNPs (release ~10 times higher at pH 12 than pH 4). 1H-NMR analysis revealed the role of alkaline hydrolysis of the ester bonds (i.e., crosslinks) in governing the pH-responsive behavior. Overall, MC/AgNPs hydrogels represent an innovative platform for the pH-triggered release of AgNPs in an alkaline milieu.
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Affiliation(s)
- Lorenzo Bonetti
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
| | - Andrea Fiorati
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Via Giuseppe Giusti 9, 50121 Florence, Italy
| | - Agnese D’Agostino
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Via Giuseppe Giusti 9, 50121 Florence, Italy
| | - Carlo Maria Pelacani
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
| | - Roberto Chiesa
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Via Giuseppe Giusti 9, 50121 Florence, Italy
| | - Silvia Farè
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Via Giuseppe Giusti 9, 50121 Florence, Italy
| | - Luigi De Nardo
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Via Luigi Mancinelli 7, 20131 Milan, Italy; (A.F.); (A.D.); (C.M.P.); (R.C.); (S.F.); (L.D.N.)
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Via Giuseppe Giusti 9, 50121 Florence, Italy
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Quantum-mechanical simulations for in vivo MR spectroscopy: Principles and possibilities demonstrated with the program NMRScopeB. Anal Biochem 2017; 529:79-97. [DOI: 10.1016/j.ab.2016.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/24/2016] [Accepted: 10/07/2016] [Indexed: 11/19/2022]
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