Using confocal Raman microscopy to real-time monitor poplar cell wall swelling and dissolution during ionic liquid pretreatment

2014 ◽  
Vol 77 (8) ◽  
pp. 609-618 ◽  
Author(s):  
Xun Zhang ◽  
Jing Ma ◽  
Zhe Ji ◽  
Gui-Hua Yang ◽  
Xia Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Ionic Liquid ◽  
Real Time ◽  
Raman Microscopy ◽  
Confocal Raman Microscopy ◽  
Ionic Liquid Pretreatment ◽  
Confocal Raman

scholarly journals Real-Time Drug Release Imaging From Nanocomposite Drug and Polymer Coatings

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Jinping Dong ◽  
Greg Haugstad ◽  
Chris Frethem ◽  
John Foley ◽  
Bob Hoerr ◽  
...  
Keyword(s):  
Drug Release ◽  
Real Time ◽  
Polymer Coatings ◽  
Raman Microscopy ◽  
Prolonged Release ◽  
Confocal Raman Microscopy ◽  
Release Process ◽  
Force Microscopy ◽  
Confocal Raman ◽  
Model Drug

The ElectroNanospray process (Nanocopoeia, Inc) transforms drugs and polymers into many nanoscale material states including powders, liquids, encapsulated particles, and coatings. This allows application of polymers and drugs to the surface of medical devices such as coronary stents in a single-stage process. A model drug delivery system consisting of a polymer matrix (arborescent polyisobutylene-polystyrene, or arbIBS) and either dexamethasone or sirolimus was studied by various characterization techniques. Modification of ElectroNanospray process parameters resulted in surface coatings with rich morphologies that are revealed by SEM, Atomic Force Microscopy (AFM) and Confocal Raman Microscopy were employed to monitor the drug release process in situ, through which the mechanism of the drug-eluting process may be proposed. A Confocal Raman microscope fitted with underwater objective was used to image arbIBS∕drug films incubated in phosphate-buffered saline over 12h and at various film depths. Drug migrated from more concentrated areas into the surrounding polymer and toward the surface, beginning as early as 5min after placing the sample in buffer and continuing throughout the 12h period. High drug levels remained in the more concentrated areas at the end of incubation, suggesting the potential for prolonged release. SEM and AFM images taken from samples post incubation showed the appearance of nanoscale pores ∼100nm in diameter in areas corresponding in size and distribution to the Confocal Raman planar image areas of increased drug concentration. Confocal Raman microscopy offers a powerful new technique for demonstrating real-time drug release from therapeutic medical device coatings.

Real-Time Monitoring of Industrial Biofilms using Confocal Raman Microscopy and Multivariate Analysis

2020 ◽  
Author(s):  
Ana Magalhaes ◽  
Pola Goldberg Oppenheimer ◽  
Tim Overton ◽  
Kevin Wright
Keyword(s):  
Cluster Analysis ◽  
Multivariate Analysis ◽  
Real Time ◽  
Raman Spectra ◽  
Bacterial Species ◽  
Raman Microscopy ◽  
Confocal Raman Microscopy ◽  
Growth Phenotype ◽  
Confocal Raman ◽  
Biofilm Development

<p>Biofilm development in industrial settings can prove costly to manufacturing and consumer health. The presence of contaminants in raw materials, finished products and on process contact surfaces negatively impacts on product quality and safety. Rapid and accurate identification of spoilage and pathogenic microorganisms is crucial to implement effective biofilm control strategies that enhance product safety. The application of confocal Raman microscopy (CRM) for non-invasive and rapid characterisation of clinical and food isolates has been reported. The question remains whether the technique can be used as an online monitoring tool for real-time measurement of biofilm build-up in dynamic manufacturing conditions.</p> <p>In this study we investigated if CRM could be used in the manufacturing environment as an alternative microbiological quality control method. We assessed if this technology is able to differentiate between bacterial species and their growth phenotype, as well as detect contaminants from process samples.</p> <p>Laboratory and industrial isolates grown under different culture conditions (planktonic, agar plates, and CDC grown biofilms), and formulated products were analysed using a confocal Raman microscope (Thermofisher DXR2xi) under optimised settings. Reference and experimental Raman spectra were collected and analysed for all test conditions [1]. Spectral similarities were evaluated by developing a microbial multivariate predictive model using a two-way orthogonal partial least squares (O2PLS) regression for cluster analysis [2].</p> <p>Optimal spectra for microbes were obtained in the fingerprint region at approximately 600 - 1800 cm<sup>-1 </sup>where characteristic peaks could be assigned to different biological macromolecules (nucleic acids, proteins, lipids and carbohydrates). Cluster analysis showed good group separation with low variation within but high variation between bacterial strains, enabling bacterial differentiation. It also highlighted the variations observed in the spectral fingerprint for planktonic, agar and biofilm growth modes. Comparative studies suggest that the peak associated with nucleotide ring stretching (~ 700 cm<sup>-1</sup>) could be used as a microbial marker for contamination in formulation.</p> <p>Our findings indicate that confocal Raman microscopy can be used for at-line monitoring of contamination in product streams. Raman spectra provide biochemical data for microbial characterisation but variations in the spectra are often difficult to observe and interpret. Multivariate statistical methods permit rapid interrogation of spectral data, with the potential to improve microbial identification. In combination with multivariate analysis, CRM can be used as an analytical tool for rapid identification of industrial isolates and differentiation of their growth phenotype.</p> <p> </p> <p><strong>References</strong></p> <p>[1] Beier, B.D., R.G. Quivey, and A.J. Berger,Raman microspectroscopy for species identification and mapping within bacterial biofilms.AMB Express, 2012. <strong>2</strong>(1): p. 35-35.</p> <p>[2] Zou, X., et al., Automatic Spectroscopic Data Categorization by Clustering Analysis (ASCLAN): A Data-Driven Approach for Distinguishing Discriminatory Metabolites for Phenotypic Subclasses.Analytical Chemistry, 2016. <strong>88</strong>(11): p. 5670-5679.</p>

scholarly journals Improvement of interfacial interaction in impregnated wood via grafting methyl methacrylate onto wood cell walls

Holzforschung ◽  
2020 ◽  
Vol 74 (10) ◽  
pp. 967-977
Author(s):  
Youming Dong ◽  
Michael Altgen ◽  
Mikko Mäkelä ◽  
Lauri Rautkari ◽  
Mark Hughes ◽  
...  
Keyword(s):  
Cell Wall ◽  
Methyl Methacrylate ◽  
Cell Walls ◽  
Wood Cell Wall ◽  
Principal Component ◽  
Interfacial Interaction ◽  
Raman Microscopy ◽  
Hydroxyl Groups ◽  
Confocal Raman Microscopy ◽  
Confocal Raman

AbstractImproving the interaction between the wood cell wall and a modifying agent is fundamental to enhancing the efficacy of wood modification. The extent of interaction is, nevertheless, difficult to evaluate due to the highly heterogeneous nature of the modified wood. In this study, methacryl groups were grafted onto the wood cell wall polymers, via the reaction between 2-isocyanatoethyl methacrylate (IEMA) and hydroxyl groups, to improve their compatibility and reactivity. Subsequently, methyl methacrylate (MMA) was introduced into methacrylated wood and copolymerized with the bonded methacryl groups. The distribution of IEMA and poly MMA (PMMA) in the wood cell walls was investigated by scanning electron microscopy (SEM) and confocal Raman microscopy. The results showed that MMA penetrated the wood cell walls and formed strong interfacial interaction, which was confirmed by confocal Raman microscopy combined with principal component analysis (PCA). With copolymerization, the highest anti-swelling efficiency (ASE) (57%) was achieved, because of the effect of methacrylation. Compared to the reference, the water resistance and hardness were significantly improved. In addition, the dynamic wettability was also altered largely due to copolymerization.

Single Layer Graphene for Estimation of Axial Spatial Resolution in Confocal Raman Microscopy Depth Profiling

2018 ◽  
Vol 91 (1) ◽  
pp. 1049-1055 ◽  
Author(s):  
Carol Korzeniewski ◽  
Jay P. Kitt ◽  
Saheed Bukola ◽  
Stephen E. Creager ◽  
Shelley D. Minteer ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Depth Profiling ◽  
Single Layer ◽  
Raman Microscopy ◽  
Single Layer Graphene ◽  
Confocal Raman Microscopy ◽  
Layer Graphene ◽  
Confocal Raman
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