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A magnetic molecularly imprinted polymer (MMIP) was synthesised and tested for an in vivo rheumatoid arthritis (RA) rat model. Magnetite coated with mesoporous silica (Fe 2 O 3 @mSi) was used as core for surface imprinting, dopamine was used as monomer and methotrexate (MTX) was loaded directly during polymerisation. The amount of MTX loaded on MMIPs reached 201.165 ± 0.315 µmol/g. Characterisation of the polymers was done via SEM, TEM, and FTIR. The pharmacological effect of the selected MMIP was evaluated in a Complete Freund's Adjuvant (CFA) induced arthritis rat model where a 3D magnet bearing construct was designed for targeted delivery of MMIPs. The parameters evaluated were the change in paw edoema, paw diameter, gait score, and animal's weight. Results revealed a tendency of MMIP to significantly improve the measured parameters which was confirmed with histopathological findings. In conclusion, the improvement in the arthritic signs associated with MMIP treatment compared to free MTX, indicated successful targeting of MMIPs to the site of inflammation.

Diamond thin-film waveguides with a nanocrystalline diamond layer of approximately 20 μm thickness were used in the mid-infrared regime in combination with quantum cascade lasers to detect the IR signature of caffeine. The diamond thin-film waveguides were fundamentally characterized with respect to their morphological properties via AFM and SEM. Theoretical simulations confirmed the feasibility of using a larger sensing area of approximately 50 mm 2 compared to conventionally used strip waveguides. A comprehensive and comparative analysis confirmed the performance of the diamond thin-film-waveguide-based sensing system vs data obtained via conventional attenuated total reflection Fourier transform infrared spectroscopy using a single-bounce diamond internal reflection element. Hence, the utility of innovative diamond thin-film-waveguide-based sensors coupled with quantum cascade laser light sources has been confirmed as an innovative analytical tool, which may be used in a wide range of application scenarios, ranging from environmental to medical sensing, taking advantage of the robustness and inertness of nanocrystalline diamond.

We report on a flexible platform for molecular sensing in the terahertz range. Merging the well-established technologies of near-infrared electro-optic modulation and photomixing realizes a spectrally adaptable terahertz source, which is combined with a new generation of compact gas cells, so-called substrate-integrated hollow waveguides (iHWGs). iHWGs have been developed in the mid-infrared and provide flexibility in the design of the optical absorption path. Here, we demonstrate its suitability for the terahertz domain by presenting its low propagation losses and by measuring rotational transitions of nitrious oxide (N 2 O). A fast frequency sideband modulation technique results in substantially reduced measurement times and increased accuracy compared to a standard wavelength tuning method.

The development of synthetic particles that emulate real viruses in size, shape, and chemical composition is vital to the development of imprinted polymer-based sorbent materials (molecularly imprinted polymers, MIPs). In this study, we address surrogates for adenovirus type 5 (Adv 5) via the synthesis and subsequent modification of icosahedral gold nanoparticles (iAuNPs) decorated with the most abundant protein of the Adv 5 (i.e., hexon protein) at the surface. CTAB-capped iAuNPs with dimensions in the range of 40-90 nm were synthesized, and then CTAB was replaced by a variety of polyethylene glycols (PEGs) in order to introduce suitable functionalities serving as anchoring points for the attachment of the hexon protein. The latter was achieved by non-covalent linking of the protein to the iAuNP surface using a PEG without reactive termination (i.e., methoxy PEG thiol, mPEG-SH, Mn=800). Alternatively, covalent anchoring points were generated by modifying the iAuNPs with a bifunctional PEG (i.e., thiol PEG amine, SH-PEG-NH 2 ) followed by the addition of glutaraldehyde. X-ray photoelectron spectroscopy (XPS) confirmed the formation of the anchoring points at the iAuNP surface. Next, the amino groups present in the amino acids of the hexon protein interacted with the glutaraldehyde. iAuNPs before and after PEGylation were characterized using dynamic light scattering (DLS), XPS, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis spectroscopy, confirming the CTAB-PEG exchange. Finally, the distinct red shift obtained in the UV-Vis spectra of the pegylated iAuNPs in the presence of the hexon protein, the increase in the hydrodynamic diameter, the change in the zeta potential, and the selective binding of the hexon-modified iAuNPs towards a hexon-imprinted polymer (HIP) confirmed success in both the covalent and non-covalent attachment at the iAuNP surface., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Antibacterial polymer materials have gained interest due to their capability to inhibit or eradicate biofilms with greater efficiency in comparison with their monomeric counterparts. Among the antimicrobial and anti-biofouling polymers, catecholamine-based polymers - and in particular polydopamine - have been studied due to their favorable adhesion properties, which can be tuned by controlling the pH value. In this study, we used atomic force microscopy (AFM)-based spectroscopy to investigate the relation between the adhesion properties and surface charge density and the pH of electrochemically deposited polydopamine films presenting a dissociation constant of polydopamine of 6.3 ± 0.2 and a point of zero charge of 5.37 ± 0.06. Furthermore, using AFM and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), the influence of the surface charge density of polydopamine on bacterial adhesion and biofilm formation was investigated. It was shown that the adhesion of Escherichia coli at positively charged polydopamine is three times higher compared to a negatively charged polymer, and that the formation of biofilms is favored at positively charged polymers., (© 2022. The Author(s).)

The rational design of molecularly imprinted polymers has evolved along with state-of-the-art experimental imprinting strategies taking advantage of sophisticated computational tools. In silico methods enable the screening and simulation of innovative polymerization components and conditions superseding conventional formulations. The combined use of quantum mechanics, molecular mechanics, and molecular dynamics strategies allows for macromolecular modelling to study the systematic translation from the pre- to the post-polymerization stage. However, predictive design and high-performance computing to advance MIP development are neither fully explored nor practiced comprehensively on a routine basis to date. In this review, we focus on different steps along the molecular imprinting process and discuss appropriate computational methods that may assist in optimizing the associated experimental strategies. We discuss the potential, challenges, and limitations of computational approaches including ML/AI and present perspectives that may guide next-generation rational MIP design for accelerating the discovery of innovative molecularly templated materials.

Lentilactobacillus parabuchneri , a lactic acid bacterium, is largely responsible for the production and accumulation of histamine, a toxic biogenic amine, in cheese. L. parabuchneri strains can form biofilms on the surface of industry equipment. Since they are resistant to cleaning and disinfection, they may act as reservoirs of histamine-producing contaminants in cheese. The aim of this study was to investigate the biofilm-producing capacity of L. parabuchneri strains. Using the crystal violet technique, the strains were first categorized as weak, moderate or strong biofilm producers. Analysis of their biofilm matrices revealed them to be mainly composed of proteins. Two strains of each category were then selected to analyze the influence on the biofilm-forming capacity of temperature, pH, carbon source, NaCl concentration and surface material (i.e., focusing on those used in the dairy industry). In general, low temperature (8 °C), high NaCl concentrations (2-3% w / v ) and neutral pH (pH 6) prevented biofilm formation. All strains were found to adhere easily to beech wood. These findings increase knowledge of the biofilm-forming capacity of histamine-producing L. parabuchneri strains and how their formation may be prevented for improving food safety.

Unlike other antimicrobial agents, Ag-based composites are stable and currently widely used as broad spectral additives, fighting microbial biofilms and other biological threats. The goal of the present study is to develop a green, multifunctional, and robust antibiofilm water-insoluble coating, inhibiting histamine-producing Lentilactobacillus parabuchneri biofilms. Herein, laser-ablated Ag NPs (L-Ag NPs) were incorporated into and onto a montmorillonite (MMT) surface layer with a simple wet chemical method, provided that the electrostatic interaction between L-Ag NPs and MMT clay led to the formation of L-Ag/MMT nanoantimicrobials (NAMs). The use of MMT support can facilitate handling Ag NPs in industrial applications. The Ag/MMT composite was characterized with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), which confirmed the entrapment of L-Ag NPs into MMT clay. The surface chemical composition was assessed with X-ray photoelectron spectroscopy, proving that Ag NPs were in contact with and deposited onto the surface of MMT. The characteristic L-Ag/MMT band was investigated with UV-vis spectroscopy. Following that, the L-Ag/MMT composite was embedded into a biosafe water-insoluble beeswax agent with a spin coating technique. The antimicrobial ion release kinetic profile of the L-Ag/MMT/beeswax coating through an electrothermal atomic absorption spectroscopy (ETAAS) study supported the controlled release of Ag ions, reaching a plateau at 420 ± 80 nM, which is safe from the point of view of Ag toxicity. Microbial biofilm growth inhibition was assessed with real-time in situ Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) in a flow cell assembly over 32 h. The study was further supported by optical density (OD) measurements and SEM on bacteria incubated in the presence of the L-Ag/MMT/beeswax coating.

An efficient capture step for human adenovirus type 5 from cell lysate was developed as an initial virus purification step from cell debris supernatant. Organosilane-based polymer particles were synthesized and experimental monomer screening allowed the selection of appropriate functionalities for the development of particles for virus binding. After elution, virus recoveries of 83 % were obtained with significant reduction of matrix proteins and residual host cell DNA. Therefore, the implemented capture strategy for adenovirus via polymer particles provides a scalable and reproducible approach to reduce time and cost during virus purification processes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Fourier-transform infrared (FTIR) spectroscopy provides rapid, reliable, quantitative, and qualitative analysis of samples in different aggregation states, i.e., gases, thin films, solids, liquids, etc. However, when analyzing aqueous solutions, particular issues associated with the rather pronounced IR absorption characteristics of water appear to interfere with the solute determination. In this review, Fourier-transform infrared spectroscopic techniques and their analytical capabilities for analyzing aqueous solutions are reviewed, and highlight examples are discussed.

Farmers, cereal suppliers and processors demand rapid techniques for the assessment of mould-associated contamination. Deoxynivalenol (DON) is among the most important Fusarium toxins and related to human and animal diseases besides causing significant economic losses. Routine analytical techniques for the analysis of DON are either based on chromatographic or immunoanalytical techniques, which are time-consuming and frequently rely on hazardous consumables. The present study evaluates the feasibility of infrared attenuated total reflection spectroscopy (IR-ATR) for the analysis of maize extracts via different solvents optimized for the determination of DON contamination along the regulatory requirements by the European Union (EU) for unprocessed maize (1750 μg kg -1 ). Reference analysis was done by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The studied maize samples were either naturally infected or had been artificially inoculated in the field with Fusarium graminearum , Fusarium culmorum or Fusarium verticillioides . Principal component analysis demonstrated that water and methanol-water (70 : 30% v) were optimum solvents for differentiating DON contamination levels. Supervised partial least squares discriminant analysis resulted in excellent classification accuracies of 86.7% and 90.8% for water and methanol-water extracts, respectively. The IR spectra of samples with fungal infection and high DON contamination had distinct spectral features, which could be related to carbohydrates, proteins and lipid content within the investigated extracts.

The increasing consumption of processed foods demands the usage of chemical preservatives to ensure freshness and extended shelf life. For this purpose, sodium sulfite and its derivatives have been widely used in a variety of food products to inhibit microbial spoilage and for mitigating oxidative decay. However, the excessive consumption of sulfite may cause health problems, thus requiring rapid and accurate analytical methods for the rapid identification of threshold levels. Conventionally, sulfite is volatilized from food samples by acidification followed by trapping of the gaseous SO 2 and determination using a suitable analytical technique. Herein, we propose a yet unprecedented reagent-less approach via direct absorbance measurements of gaseous SO 2 at 280 nm after sample acidification. The detection system combines a deep-UV LED and a SiC photodiode with a substrate-integrated hollow waveguide (iHWG) gas cell. Absorbance measurements were performed using a log-ratio amplifier circuitry, resulting in noise levels <0.7 mAU. This innovative concept enabled the determination of sulfite in beverages in the range of 25-1000 mg L -1 with suitable linearity (r 2  > 0.99) and an analysis time <30 s. The limit of detection (LOD) was calculated at 14.3 mg L -1 (3σ) with an iHWG providing an optical path length of 75 mm. As a proof of concept, this innovative analytical platform was employed for sulfite quantification in concentrated grape juice, coconut water and beer, with suitable accuracy in terms of recovery (83-117%) and favorable comparison with the official Monier-Williams method. Given the inherent modularity and adaptability of the device concept, we anticipate the application of the proposed analytical platform for the in-situ studies addressing sulfite and other volatilized preservatives in a wide variety of food products with tailorable detectability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Antimicrobial materials are considered potential alternatives to prevent the development of biofilm-associated contaminations. Concerns regarding synthetic preservatives necessitate the development of innovative and safe natural antimicrobials. In the present study, we discuss the in situ infrared attenuated total reflection spectroscopy (IR-ATR) investigations of the selective antimicrobial efficiency of chitosan in controlling the growth of Lentilactobacillus parabuchneri biofilms. The protonated charges of chitosan were additionally amplified by structural modification via methylation, yielding quaternized derivative TMC (i.e., N, N, N-trimethyl chitosan). To evaluate antimicrobial effectiveness against L. parab . biofilms, IR-ATR spectroscopy provided information on molecular mechanisms and insights into chemical changes during real-time biofilm inhibition studies. The integrated fiberoptic oxygen microsensors enabled monitoring oxygen (O 2 ) concentration gradients within biofilms, thereby confirming the metabolic oxygen depletion dropping from 4.5 to 0.7 mg L -1 . IR studies revealed strong electrostatic interactions between chitosan/its water-soluble derivative and bacteria, indicating that a few hours were sufficient to affect biofilm disruption. The significant decrease in the IR bands is related to the characteristic spectral information of amide I, II, III, nucleic acid, and extracellular polymeric matrix (EPS) produced by L. parabuchneri biofilms. Cell clusters of biofilms, microcolonies, and destabilization of the EPS matrix after the addition of biopolymers were visualized using optical microscopy. In addition, scanning electron microscopy (SEM) of biofilms grown on polystyrene and stainless-steel surfaces was used to examine morphological changes, indicating the disintegration of the biofilm matrix into individual cells. Quantification of the total biofilm formation correlated with the CV assay results, indicating cell death and lysis. The electrostatic interactions between chitosan and the bacterial cell wall typically occur between protonated amino groups and negatively charged phospholipids, which promote permeabilization. Biofilm growth inhibition was assessed by a viability assay for a period of 72 h and in the range of low MIC values (varying 0.01-2%). These results support the potential of chitosan and TMC for bacterial growth prevention of the foodborne contaminant L. parabuchneri in the dairy industry and for further implementation in food packaging.

Foodborne pathogenic microorganisms form biofilms at abiotic surfaces, which is a particular challenge in food processing industries. The complexity of biofilm formation requires a fundamental understanding on the involved molecular mechanisms, which may then lead to efficient prevention strategies. In the present study, biogenic amine producing bacteria, i.e., Lentilactobacillus parabuchneri DSM 5987 strain isolated from cheese were studied in respect with biofilm formation, which is of substantial relevance given their contribution to the presence of histamine in dairy products. While scanning electron microscopy was used to investigate biofilm adhesion at stainless steel surfaces, in situ infrared attenuated total reflection spectroscopy (IR-ATR) using a custom flow-through assembly was used for real-time and non-destructive observations of biofilm formation during a period of several days. The spectral window of 1700-600 cm -1 provides access to vibrational signatures characteristic for identifying and tracking L. parabuchneri biofilm formation and maturation. Especially, the amide I and II bands, lactic acid produced as the biofilm matures, and a pronounced increase of bands characteristic for extracellular polymeric substances (EPS) provide molecular insight into biofilm formation, maturation, and changes in biofilm architecture. Finally, multivariate data evaluation strategies were applied facilitating the unambiguous classification of the observed biofilm changes via IR spectroscopic data., (© 2022. The Author(s).)

Rare cancers are a challenge for clinical practice, the treatment experience at major centers to which rare cancers are referred is limited and are the most difficult to diagnose. Research to identify causes or develop prevention and early detection strategies is extremely challenging. Anal cancer is an example of a rare cancer, with the human papillomavirus (HPV) infection being the most important risk factor associated. In the early stages, anal cancer does not exhibit evident symptoms. This disease is diagnosed by means of anoscopy, which diagnoses some cases of early cancer; nevertheless, sensitivity of this test ranges between 47 and 89%. Therefore, the development of new, effective, and evidence-based screening methodologies for the early detection of rare cancers is of great relevance. In this study, the potential of ATR-FTIR spectroscopy has been explored as a sensitive, nondestructive, and inexpensive analytical method for developing disease screening platforms in serum. Spectral differences were found in the regions of 1700-1100 and 1700-1400 cm -1 between the control group and the anal cancer group related to the presence of proteins and nucleic acids. The chemometric analysis presented differences in the spectral fingerprints for both spectral regions with a high sensitivity ranging from 95.2 to 99.9% and a specificity ranging from 99.2 to 100%. This is the first step that we report for a methodology that is fast, nondestructive, and easy to perform, and the high sensitivity and specificity of the method are the basis for extensive research studies to implement these technologies in the clinical field.

This manuscript reports the design and fabrication of conducting plastibody based electrochemical sensor for the detection of Salmonella typhimurium. The conductive plastibody was fabricated on an Indium Tin Oxide surface through potentiostatic method (electrodeposition for 400 s), wherein a polymer mix of pyrrole, lactic acid, ammonium chloride, and sodium dodecyl sulfate was employed for the electrodeposition. Various template removal methods were tested and electrochemical cleaning in the MES buffer was found to be the most suitable, which was optimized further. The synthesized plastibody sensors were characterized using electrochemical impedance spectroscopy, contact angle, FTIR spectroscopy and scanning electron microscopy. Amperometry was used as the electrochemical analytical technique for the determination of the analyte in the concentration range of 10 0 -10 8 CFU/mL having a limit of detection of 3.42 CFU/mL. Sensor's performance was also compared with the non-imprinted electrode and an imprinting factor of 3.8 was found. The plastibody sensor was tested against other bacteria and coefficient of selectivity was calculated to be 1.0, 10.8, 5.6 and 2.4 towards S. typhi, S. aureus, E. coli and L. monocytogenes respectively. The sensor was also found to be reproducible in nature (RSD 0.11 %) and this generic concept presented herein may be extended for the detection of pathogens in other matrices as well., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In silico methods enable optimizing artificial receptors such that constructive mimics of natural antibodies can be envisaged. The introduction of combinatorial synthesis strategies via multi-monomer combinations has improved the performance of molecularly imprinted polymers (MIP) significantly. However, it remains experimentally challenging to screen thousands of combinations resulting from a large library of monomers. The present study introduces a molecular mechanics based multi-monomer simultaneous docking approach (MMSD) to computationally screen monomer combinations according to their potential, facilitating selective molecular imprints. Thereby, the diversity of multipoint interactions realizable with a peptide surface is efficiently explored yielding how individual monomer binding capacities constructively or adversely add up when docked together. Additionally, spatially distributed molecular models were mapped for analyzing intermolecular H-bonding and hydrophobic interactions resulting from single monomer docking, as well as bi- and tri-monomer simultaneous docking. A direct impact of complex formation on the binding capacity of the resulting MIPs has been observed. In a first small-scale study, the predictive potential of the MMSD approach was validated via experimentally applied polymer combinations for peptide imprinting via the scoring functions established during the screening process. MMSD clearly enables rational design of MIPs for synthesizing more sensitive and selective artificial receptor materials especially for peptide and protein-epitope templates.

In the mid-infrared (MIR) spectral range, a series of applications have successfully been shown in the fields of sensing, security and defense, energy conservation, and communications. In particular, rapid and recent developments in MIR light sources have significantly increased the interest in developing MIR optical systems, sensors, and diagnostics especially for chem/bio detection schemes and molecular analytical application scenarios. In addition to the advancements in optoelectronic light sources, and especially quantum and interband cascade lasers (QCLs, ICLs) largely driving the increasing interest in the MIR regime, also thermal emitters and light emitting diodes (LEDs) offer opportunities to alternatively fill current gaps in spectral coverage specifically with analytical applications and chem/bio sensing/diagnostics in the focus. As MIR laser technology has been broadly covered in a variety of articles, the present review aims at summarizing recent developments in MIR non-laser light sources highlighting their analytical utility in the MIR wavelength range., (© 2022. The Author(s).)

Quinic acid (QA) and its ester conjugates have been subjected to in-depth scientific investigations for their antioxidant properties. In this study, molecularly imprinted polymers (MIPs) were used for selective extraction of quinic acid (QA) from coffee bean extract. Computational modelling was performed to optimize the process of MIP preparation. Three different functional monomers (allylamine, methacrylic acid (MAA) and 4-vinylpyridine (4-VP)) were tested for imprinting. The ratio of each monomer to template chosen was based on the optimum ratio obtained from computational studies. Equilibrium rebinding studies were conducted and MIP C, which was prepared using 4-VP as functional monomer with template to monomer ratio of 1:5, showed better binding performance than the other prepared MIPs. Accordingly, MIP C was chosen to be applied for selective separation of QA using solid-phase extraction. The selectivity of MIP C towards QA was tested versus its analogues found in coffee (caffeic acid and chlorogenic acid). Molecularly imprinted solid-phase extraction (MISPE) using MIP C as sorbent was then applied for selective extraction of QA from aqueous coffee extract. The applied MISPE was able to retrieve 81.918 ± 3.027% of QA with a significant reduction in the amount of other components in the extract., Competing Interests: The authors declare no conflicts of interest.

A THz-TDS spectrometer (terahertz time-domain spectroscopy) with ASOPS technology (asynchronous optical sampling) was employed in this study, aiming to explore the potential of the technique and to develop analytical applications for the identification of some saccharides. Analytical curves with linear responses were obtained in the saccharide concentration range from 1.7 to 11.7 ( w / w ). The characteristic peaks used for each sugar for univariate calibrations were fructose (1.704 THz), sucrose (1.827 THz), glucose (1.435 THz), lactose (1.373 THz), saccharin (2.664 THz), and sucralose (2.219 THz). Limits of detection around 1.0% ( m / m ) were obtained. Gaussian peak fitting was also employed as a tool to aid in the identification of saccharide components in mixtures and it was observed that the region between 0.5 and 2.0 THz is more adequate for such analysis since scattering is less evident. It was observed that in a mixture of sucrose, glucose and lactose (5% or 10% ( m / m ) each) in the range of 1.31 to 1.51 THz some sub-peaks of pure lactose and glucose can be identified.

This work elaborates the effect of dynamic irradiation on light-driven molecular water oxidation to counteract deactivation. It highlights the importance of overall reaction engineering to overcome limiting factors in artificial photosynthesis reactions. Systematic investigation of a homogeneous three-component ruthenium-based water oxidation system revealed significant potential to enhance the overall catalytic efficiency by synchronizing the timescales of photoreaction and mass transport in a capillary flow reactor. The overall activity could be improved by a factor of more than 10 with respect to the turnover number and a factor of 31 referring to the external energy efficiency by controlling the local availability of photons. Detailed insights into the mechanism of light driven water oxidation could be obtained using complementary methods of investigation like Raman, IR, and UV/Vis/emission spectroscopy, unraveling the importance of avoiding high concentrations of excited photosensitizers., (© 2022 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Silver-fluoropolymer (Ag-CF X ) composed of encapsulated bioactive nanophases within a thin polymer coating are promising antimicrobial films with excellent bioactivity. In this contribution, we report on Ag-CF X thin films obtained by ion beam co-sputtering, accurately tuning film thickness, and inorganic loading. The Ag-CF X films were characterized by spectroscopic and scanning probe microscopy techniques with respect to composition and swelling behavior. Next to electrothermal atomic absorption spectroscopy (ETAAS) studies, scanning electrochemical microscopy (SECM) experiments in combination with anodic stripping voltammetry (ASV) were carried out to study the release mechanism of silver(I) from the embedded silver nanoparticles (AgNPs). Silver(I) concentration profiles at the Ag-CF X films in contact with water resulted in a release of 1310 ± 50 μg L -1 (n = 3) after 27 h of immersion and corresponded well to the swelling of the films. The antimicrobial properties towards biofilm formation of P. fluorescens were studied by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy during a period of 48 h. The obtained IR data revealed biofilm inhibition due to the presence of the antimicrobial layer but also indicated potential surface re-colonization after 30 h of contact with the bacteria-containing solution. The occurrence of cyclic changes in the characteristic IR bands correlated with apparent stress of bottom-layered bacteria, along with re-colonization on top of dead biomass, indicative of potential cannibalism events., (Copyright © 2022. Published by Elsevier B.V.)

Over recent years, great efforts have been extensively documented in top scientific journals on the development of methods for early diagnosis, treatment, and monitoring of cancers which are prevalent critical diseases with a high mortality rate among men and women. The determination of cancer biomarkers using different optimum methodologies is one of the finest options for achieving these goals with more precision, speed, and at a lower cost than traditional clinical procedures. In this regard, while focusing on specific biomarkers, molecularly imprinted technology has enabled novel diagnostic techniques for a variety of diseases. Due to the well-known advantages of molecularly imprinted polymers (MIPs), this review focuses on the current trends of MIPs-based extraction/microextraction methods, specifically targeting cancer biomarkers from various matrices. These optimized methods have demonstrated high selectivity, accuracy, sorbent reusability, extraction recovery, and low limits of detection and quantification for a variety of cancer biomarkers, which are a powerful tool to provide early diagnosis, prognosis, and treatment monitoring, with potential clinical application expected soon. This review highlights the key progress, specific modifications, and strategies used for MIP synthesis. The future perspectives for cancer biomarkers purification and determination by fabricating MIP-based techniques are also discussed., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background and Objective: Prompt pathogen identification of blood stream infections is essential to provide appropriate antibiotic treatment. Therefore, the objective of this prospective single centre study was to establish an inexpensive, fast and accurate protocol for bacterial species identification with SDS protein-extraction directly from BacT/Alert® blood culture (BC) bottles by VitekMS®., Results: Correct species identification was obtained for 198/266 (74.4%, 95%-CI = [68.8%, 79.6%]) of pathogens. The protocol was more successful in identifying 87/96 (91.4%, 95%-CI = [83.8%, 93.2%]) gram-negative bacteria than 110/167 (65.9%, 95%-CI = [58.1%, 73.0%]) gram-positive bacteria. The hands-on time for sample preparation and measurement was about 15 min for up to five samples. This is shorter than for most other protocols using a similar lysis-centrifugation approach for the combination of BacT/Alert® BC bottles and the Vitek® MS mass spectrometer. The estimated costs per sample were approx. 1.80€ which is much cheaper than for commercial kits., Conclusion: This optimized protocol allows for accurate identification of bacteria directly from blood culture bottles for laboratories equipped with BacT/Alert® blood culture bottles and VitekMS® mass spectrometer., Competing Interests: The authors have declared that no competing interests exist.

Preclassification of raw infrared spectra has often been neglected in scientific literature. Separating spectra of low spectral quality, due to low signal-to-noise ratio, presence of artifacts, and low analyte presence, is crucial for accurate model development. Furthermore, it is very important for sparse data, where it becomes challenging to visually inspect spectra of different natures. Hence, a preclassification approach to separate infrared spectra for sparse data is needed. In this study, we propose a preclassification approach based on Multiplicative Signal Correction (MSC). The MSC approach was applied on human and the bovine knee cartilage broadband Fourier Transform Infrared (FTIR) spectra and on a sparse data subset comprising of only seven wavelengths. The goal of the preclassification was to separate spectra with analyte-rich signals (i.e., cartilage) from spectra with analyte-poor (and high-matrix) signals (i.e., water). The human datasets 1 and 2 contained 814 and 815 spectra, while the bovine dataset contained 396 spectra. A pure water spectrum was used as a reference spectrum in the MSC approach. A threshold for the root mean square error (RMSE) was used to separate cartilage from water spectra for broadband and the sparse spectral data. Additionally, standard noise-to-ratio and principle component analysis were applied on broadband spectra. The fully automated MSC preclassification approach, using water as reference spectrum, performed as well as the manual visual inspection. Moreover, it enabled not only separation of cartilage from water spectra in broadband spectral datasets, but also in sparse datasets where manual visual inspection cannot be applied.

Histopathological diagnosis is the current standard for the classification of brain and spine tumors. Raman spectroscopy has been reported to allow fast and easy intraoperative tissue analysis. Here, we report data on the intraoperative implementation of a stimulated Raman histology (SRH) as an innovative strategy offering intraoperative near real-time histopathological analysis. A total of 429 SRH images from 108 patients were generated and analyzed by using a Raman imaging system (Invenio Imaging Inc.). We aimed at establishing a dedicated workflow for SRH serving as an intraoperative diagnostic, research, and quality control tool in the neurosurgical operating room (OR). First experiences with this novel imaging modality were reported and analyzed suggesting process optimization regarding tissue collection, preparation, and imaging. The Raman imaging system was rapidly integrated into the surgical workflow of a large neurosurgical center. Within a few minutes of connecting the device, the first high-quality images could be acquired in a "plug-and-play" manner. We did not encounter relevant obstacles and the learning curve was steep. However, certain prerequisites regarding quality and acquisition of tissue samples, data processing and interpretation, and high throughput adaptions must be considered. Intraoperative SRH can easily be integrated into the workflow of neurosurgical tumor resection. Considering few process optimizations that can be implemented rapidly, high-quality images can be obtained near real time. Hence, we propose SRH as a complementary tool for the diagnosis of tumor entity, analysis of tumor infiltration zones, online quality and safety control and as a research tool in the neurosurgical OR., (© 2021. The Author(s).)

Intraoperative histopathological examinations are routinely performed to provide neurosurgeons with information about the entity of tumor tissue. Here, we quantified the neuropathological interpretability of stimulated Raman histology (SRH) acquired using a Raman laser imaging system in a routine clinical setting without any specialized training or prior experience. Stimulated Raman scattering microscopy was performed on 117 samples of pathological tissue from 73 cases of brain and spine tumor surgeries. A board-certified neuropathologist - novice in the interpretation of SRH - assessed image quality by scoring subjective tumor infiltration and stated a diagnosis based on the SRH images. The diagnostic accuracy was determined by comparison to frozen hematoxylin-eosin (H&E)-stained sections and the ground truth defined as the definitive neuropathological diagnosis. The overall SRH imaging quality was rated high with the detection of tumor cells classified as inconclusive in only 4.2% of all images. The accuracy of neuropathological diagnosis based on SRH images was 87.7% and was non-inferior to the current standard of fast frozen H&E-stained sections (87.3 vs. 88.9%, p = 0.783). We found a substantial diagnostic correlation between SRH-based neuropathological diagnosis and H&E-stained frozen sections (κ = 0.8). The interpretability of intraoperative SRH imaging was demonstrated to be equivalent to the current standard method of H&E-stained frozen sections. Further research using this label-free innovative alternative vs. conventional staining is required to determine to which extent SRH-based intraoperative decision-making can be streamlined in order to facilitate the advancement of surgical neurooncology., (© 2021. The Author(s).)

Objective: To evaluate the feasibility of Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy to detect cartilage degradation due to osteoarthritis and to validate the methodology with osteochondral human cartilage samples for future development towards clinical use., Design: Cylindrical ( d  ​= ​4 ​mm) osteochondral samples ( n  ​= ​349) were prepared from nine human cadavers and measured with FTIR-ATR spectroscopy. Afterwards, the samples were assessed with Osteoarthritis Research Society International (OARSI) osteoarthritis cartilage histopathology assessment system and divided into two groups: 1) healthy (OARSI 0-2) and 2) osteoarthritic (OARSI 2.5-6). The classification was done with partial least squares discriminant analysis model utilizing cross-model validation. Receiver operating characteristics curve analysis was performed and the area under curve (AUC) was calculated., Results: For all samples combined, classification accuracy was 73% with AUC of 0.79. Femoral samples had accuracy of 74% and AUC of 0.77, while tibial samples had accuracy of 66%, and AUC of 0.74. Patellar samples had accuracy of 84% and AUC of 0.91., Conclusions: The results indicate that FTIR-ATR spectroscopy can differentiate between healthy and osteoarthritic femoral, tibial and patellar human tissue. If combined with a fiber optic probe, FTIR-ATR spectroscopy could provide additional objective intraoperative information during arthroscopic surgeries, which could improve clinical outcomes., (© 2022 The Authors.)

Biofilms are a major cause of health and environmental issues. Bacteria organized in biofilms are much more resistant to biocides than their equivalents in the planktonic state. In this context, spectroscopic techniques have significantly contributed to a more fundamental understanding of biofilm formation, which is crucial to prevent and limit their generation, spreading, and maturation. In this review, recent progress on the main analytical approaches enabling the spectroscopic characterization of microbial biofilms is comparatively discussed. In addition, less commonly used techniques, facilitating biofilm studies, will be also presented. Advantages and drawbacks of each discussed technique will be underlined, thus providing an overview on spectroscopic approaches for studying biofilms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Molecular imprinting has proven to be a versatile and simple strategy to obtain selective materials also termed "plastic antibodies" for a wide variety of species, i.e., from ions to macromolecules and viruses. However, to the best of the authors' knowledge, the development of epitope-imprinted polymers for selective binding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not reported to date. An epitope from the SARS-CoV-2 spike protein comprising 17 amino acids is used as a template during the imprinting process. The interactions between the epitope template and organosilane monomers used for the polymer synthesis are predicted via molecular docking simulations. The molecularly imprinted polymer presents a 1.8-fold higher selectivity against the target epitope compared to non-imprinted control polymers. Rebinding studies with pseudoviruses containing SARS-CoV-2 spike protein demonstrate the superior selectivity of the molecularly imprinted matrices, which mimic the interactions of angiotensin-converting enzyme 2 receptors from human cells. The obtained results highlight the potential of SARS-CoV-2 molecularly imprinted polymers for a variety of applications including chem/biosensing and antiviral delivery., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. Advanced Materials Interfaces published by Wiley‐VCH GmbH.)

The ongoing COVID-19 pandemic represents a considerable risk for the general public and especially for health care workers. To avoid an overloading of the health care system and to control transmission chains, the development of rapid and cost-effective techniques allowing for the reliable diagnosis of individuals with acute respiratory infections are crucial. Uniquely, the present study focuses on the development of a direct face mask sampling approach, as worn (i.e., used) disposable face masks contain exogenous environmental constituents, as well as endogenously exhaled breath aerosols. Optical techniques-and specifically infrared (IR) molecular spectroscopic techniques-are promising tools for direct virus detection at the surface of such masks. In the present study, a rapid and non-destructive approach for monitoring exposure scenarios via medical face masks using attenuated total reflection infrared spectroscopy is presented. Complementarily, IR external reflection spectroscopy was evaluated in comparison for rapid mask analysis. The utility of a face mask-based sampling approach was demonstrated by differentiating water, proteins, and virus-like particles sampled onto the mask. Data analysis using multivariate statistical algorithms enabled unambiguously classifying spectral signatures of individual components and biospecies. This approach has the potential to be extended towards the rapid detection of SARS-CoV-2-as shown herein for the example of virus-like particles which are morphologically equivalent to authentic virus-without any additional sample preparation or elaborate testing equipment at laboratory facilities. Therefore, this strategy may be implemented as a routine large-scale monitoring routine, e.g., at health care institutions, nursing homes, etc. ensuring the health and safety of medical personnel., (© 2022. The Author(s).)

The aim of the study was to optimize preprocessing of sparse infrared spectral data. The sparse data were obtained by reducing broadband Fourier transform infrared attenuated total reflectance spectra of bovine and human cartilage, as well as of simulated spectral data, comprising several thousand spectral variables into datasets comprising only seven spectral variables. Different preprocessing approaches were compared, including simple baseline correction and normalization procedures, and model-based preprocessing, such as multiplicative signal correction (MSC). The optimal preprocessing was selected based on the quality of classification models established by partial least squares discriminant analysis for discriminating healthy and damaged cartilage samples. The best results for the sparse data were obtained by preprocessing using a baseline offset correction at 1800 cm -1 , followed by peak normalization at 850 cm -1 and preprocessing by MSC.

The objective of this research was to evaluate the application of an electronic nose and chemometric analysis to discriminate volatile organic compounds between patients with COVID-19, post-COVID syndrome and controls in exhaled breath samples. A cross-sectional study was performed on 102 exhaled breath samples, 42 with COVID-19, 30 with the post-COVID syndrome and 30 control subjects. Breath-print analysis was performed by the Cyranose 320 electronic nose with 32 sensors. Group data were evaluated by Principal Component Analysis (PCA), Canonical Discriminant Analysis (CDA), and Support Vector Machine (SVM), and the test's diagnostic power was evaluated through a Receiver Operaring Characteristic curve(ROC curve). The results of the chemometric analysis indicate in the PCA a 97.6% (PC 1  = 95.9%, PC 2  = 1.0%, PC 3  = 0.7%) of explanation of the variability between the groups by means of 3 PCs, the CDA presents a 100% of correct classification of the study groups, SVM a 99.4% of correct classification, finally the PLS-DA indicates an observable separation between the groups and the 12 sensors that were related. The sensitivity, specificity of post-COVID vs. controls value reached 97.6% (87.4%-99.9%) and 100% (88.4%-100%) respectively, according to the ROC curve. As a perspective, we consider that this technology, due to its simplicity, low cost and portability, can support strategies for the identification and follow-up of post-COVID patients. The proposed classification model provides the basis for evaluating post-COVID patients; therefore, further studies are required to enable the implementation of this technology to support clinical management and mitigation of effects., (Copyright © 2021 Elsevier B.V. All rights reserved.)

An innovative mid-infrared spectroscopic sensor system based on quantum cascade lasers has been developed. The system combines the versatility of substrate-integrated hollow waveguides (IHWGs) with the robustness of attenuated total reflection (ATR) crystals employed as internal reflection waveguides for evanescent field sensing. IHWGs are highly reflective metal structures that propagate infrared (IR) radiation and were used as light pipes for coupling radiation into the ATR waveguide. The combined IHWG-ATR device has been designed such that the utmost stability and robustness of the optical alignment were ensured. This novel assembly enables evanescent field absorption measurements at yet unprecedently harsh conditions, that is, high pressure and temperature. Combining these advantages, this innovative sensor assembly is perfectly suited for taking ATR spectroscopy into the field where the robustness of the assembly and optical alignment is essential.

A β-cyclodextrin-decorated magnetic activated carbon adsorbent was prepared and characterized using various analytical techniques (X-ray diffraction (XRD), scanning electron microscopy-electron diffraction spectroscopy (SEM-EDS) and transmission electron microscopy (TEM)), and the adsorbent was used in the development of a magnetic solid-phase microextraction (MSPE) method for the preconcentration of estrone, β-estradiol, hydrocortisone and progesterone in wastewater and river water samples. This method was optimized using the central composite design in order to determine the experimental parameters affecting the extraction procedure. The quantification of hormones was achieved using high-performance liquid chromatography equipped with a photodiode array detector (HPLC-DAD). Under optimum conditions, the linearity ranged from 0.04 to 300 µg L -1 with a correlation of determinations of 0.9969-0.9991. The limits of detection and quantification were between 0.01-0.03 and 0.033-0.1 µg L -1 , with intraday and interday precisions at 1.1-3.4 and 3.2-4.2. The equilibrium data were best described by the Langmuir isotherm model, and high adsorption capacities (217-294 mg g -1 ) were obtained. The developed procedure demonstrated high potential as an effective technique for use in wastewater samples without significant interferences, and the adsorbent could be reused up to eight times.

Scientific questions in fields such as catalysis, monitoring of biological processes, or environmental chemistry demand analytical technologies combining orthogonal spectroscopies. Combined spectroscopic concepts facilitate in situ online monitoring of dynamic processes providing a better understanding of the involved reaction pathways. In the present study, a low-liquid-volume multispectroscopic platform was developed based on infrared attenuated total reflection (IR-ATR) spectroscopy combined with Raman spectroscopy and luminescence sensing. To demonstrate the measurement capabilities, exemplary analyte systems including water/heavy water and aqueous solutions of ammonium sulfate were analyzed as proof-of-principle studies. It was successfully demonstrated that three optical techniques may be integrated into a single analytical platform without interference providing synchronized and complementary data sets by probing the same minute sample volume. In addition, the developed assembly provides a gastight lid sealing the headspace above the probed liquid for monitoring the concentration of molecular oxygen also in the gas phase via luminescence quenching. Hence, the entire assembly may be operated at inert conditions, as required, for example, during the analysis of photocatalytic processes., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Virus-imprinted polymers were synthesized via surface imprinting strategies to produce core-shell imprinted particles selective for human adenovirus type 5. High binding affinity of the target virus towards the resulting imprinted layer was confirmed and unspecific binding was reduced in presence of blocking agents, i.e., via bovine serum albumin and skim milk in combination with Tween 20. In addition, the imprinted materials were applied for adenovirus extraction from cell culture supernatants. High levels of virus binding with negligible binding of matrix proteins confirmed the suitability of these materials for binding and extraction of the target virus from complex matrices.

We report IR and UV/Vis spectroscopic signatures that allow discriminating between the oxidation states of the manganese-based water oxidation catalyst [(Mn 4 O 4 )(V 4 O 13 )(OAc) 3 ] 3- . Simulated IR spectra show that V=O stretching vibrations in the 900-1000 cm -1 region shift consistently by about 20 cm -1 per oxidation equivalent. Multiple bands in the 1450-1550 cm -1 region also change systematically upon oxidation/reduction. The computed UV/Vis spectra predict that the spectral range above 350 nm is characteristic of the managanese-oxo cubane oxidation state, whereas transitions at higher energy are due to the vanadate ligand. The presence of absorption signals above 680 nm is indicative of the presence of Mn III atoms. Spectroelectrochemical measurements of the oxidation from [Mn 2 III Mn 2 IV ] to [Mn 4 IV ] showed that the change in oxidation state can indeed be tracked by both IR and UV/Vis spectroscopy., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Protein imprinted MIPs show notable potential for applications in many analytical areas such as clinical analysis, medical diagnostics and environmental monitoring, but also in drug delivery scenarios. In this study, we present various modifications of two different synthesis routes to create imprinted core-shell particles serving as a synthetic recognition material for the protein hen egg white (HEW) lysozyme. HEW lysozyme is used as food additive E 1105 for preservation due to its antibacterial effects. For facilitating quality and regulatory control analysis in food matrices, it is necessary to apply suitable isolation methods as potentially provided by molecularly imprinted materials. The highest binding capacity achieved herein was 58.82 mg/g with imprinting factors ranging up to 2.74, rendering these materials exceptionally suitable for selectively isolating HEW lysozyme.

The development of new methods for the rapid, sensitive, and selective detection of SARS-CoV-2 is a key factor in overcoming the global pandemic that we have been facing for over a year. In this work, we focused on the preparation of magnetic molecularly imprinted polymers (MMIPs) based on the self-polymerization of dopamine at the surface of magnetic nanoparticles (MNPs). Instead of using the whole SARS-CoV-2 virion as a template, a peptide of the viral spike protein, which is present at the viral surface, was innovatively used for the imprinting step. Thus, problems associated with the infectious nature of the virus along with its potential instability when used as a template and under the polymerization conditions were avoided. Dopamine was selected as a functional monomer following a rational computational screening approach that revealed not only a high binding energy of the dopamine-peptide complex but also multi-point interactions across the entire peptide template surface as opposed to other monomers with similar binding affinity. Moreover, variables affecting the imprinting efficiency including polymerization time and amount of peptide and dopamine were experimentally evaluated. Finally, the selectivity of the prepared MMIPs vs. other peptide sequences (i.e., from Zika virus) was evaluated, demonstrating that the developed MMIPs were only specific for the target SARS-CoV-2 peptide.

Absorption-based spectroscopy in the mid-infrared (MIR) spectral range (i.e., 2.5-25 μm) is an excellent choice for directly sensing trace gas analytes providing discriminatory molecular information due to inherently specific fundamental vibrational, rovibrational, and rotational transitions. Complimentarily, the miniaturization of optical components has aided the utility of optical sensing techniques in a wide variety of application scenarios that demand compact, portable, easy-to-use, and robust analytical platforms yet providing suitable accuracy, sensitivity, and selectivity. While MIR sensing technologies have clearly benefitted from the development of advanced on-chip light sources such as quantum cascade and interband cascade lasers and equally small MIR detectors, less attention has been paid to the development of modular/tailored waveguide technologies reproducibly and reliably interfacing photons with sample molecules in a compact format. In this context, the first generation of a new type of hollow waveguides gas cells-the so-called substrate-integrated hollow waveguides (iHWG)-with unprecedented compact dimensions published by the research team of Mizaikoff and collaborators has led to a paradigm change in optical transducer technology for gas sensors. Features of iHWGs included an adaptable (i.e., designable) well-defined optical path length via the integration of meandered hollow waveguide structures at virtually any desired dimension and geometry into an otherwise planar substrate, a high degree of robustness, compactness, and cost-effectiveness in fabrication. Moreover, only a few hundred microliters of gas samples are required for analysis, resulting in short sample transient times facilitating a real-time monitoring of gaseous species in virtually any concentration range. In this review, we give an overview of recent advancements and achievements since their introduction eight years ago, focusing on the development of iHWG-based mid-infrared sensor technologies. Highlighted applications ranging from clinical diagnostics to environmental and industrial monitoring scenarios will be contrasted by future trends, challenges, and opportunities for the development of next-generation portable optical gas-sensing platforms that take advantage of a modular and tailorable device design., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Ozone is an oxidizing molecule used for disinfecting a wide variety of environments, such as in dental clinics, and has most recently been promoted as a sanitizing agent to prevent coronavirus transmission. The easy access to ozone-generating sources also enables their ubiquitous use. However, exposure to ozone may seriously affect human health by amplifying or inducing respiratory diseases and distress syndromes and has been associated with premature deaths from other diseases. In this scenario, miniaturized, low-cost, and portable optical sensors based on the absorption signature of ozone in the ultraviolet (UV) range of the electromagnetic spectrum are an innovative approach for providing real-time monitoring of gaseous ozone, ensuring the safety of indoor and workplace environments. In this paper, a miniaturized ozone sensor based on the absorption signature of ozone at deep-UV frequencies was developed by integration of so-called substrate-integrated hollow waveguides (iHWG) with a miniaturized ultraviolet lamp and a fiber-optic USB-connected spectrophotometer. The innovative concept of iHWGs facilitates unprecedented compact dimensions with a high degree of flexibility in the optical design of the actual photon absorption path. The proposed device rapidly responded to the presence of ozone (<1 min) and revealed a suitable linearity ( r 2 > 0.99) in the evaluated concentration range. The limit of detection was determined at 29.4 ppbv, which renders the device suitable for measurements in the threshold range of the main regulatory agencies. Given the adaptability and modularity of this platform, we anticipate the application of this innovative concept to be equally suitable for the in situ and real-time analysis of other relevant gases providing suitable UV absorption signatures., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Background: Deep surgical site infections (dSSIs) after instrumented spinal surgery pose major therapeutic challenges. Standard treatment involves surgical debridement, wound drainage, and long-term antibiotic administration. Autologous platelet-rich fibrin (PRF) constitutes a biomaterial obtained from patients' own blood that contains leukocytes, chemokines and growth factors boosting cicatrization. Due to favorable results reported from other surgical disciplines such as dentistry, orthopedics, maxillofacial and plastic surgery using PRF, the authors hypothesized that PRF augmentation will promote wound healing in dSSIs., Objective: To report our preliminary results on the safety and efficacy of autologous-PRF as an add-on therapy on a pilot case series of persistent dSSI after instrumented spinal surgery., Methods: Among the 293 patients who underwent dorsal decompression and stabilization of the cervical, thoracic, and lumbar spine due to degenerative diseases in our department, 12 patients (4%) presented persisting dSSI after standard wound debridement and antibiotic treatment. PRF augmentation was used during a second surgical revision as an add-on therapy to standard debridement. In all cases, the wound was primarily closed without drains., Results: Wound healing was completed between 14 and 21 days after the second surgical revision in all patients. At a median follow-up of 8 months (range: 6 to 18 months), no recurrence of dSSI nor complications were encountered in any case., Conclusions: Our preliminary results suggest that PRF augmentation in persistent dSSI after instrumented spinal surgery appears to be a safe and effective strategy to promote wound healing. Prospective controlled studies are required to define the efficiency of PRF more clearly in both treating and preventing dSSI., (© 2021. The Author(s).)

Despite their technological importance for water splitting, the reaction mechanisms of most water oxidation catalysts (WOCs) are poorly understood. This paper combines theoretical and experimental methods to reveal mechanistic insights into the reactivity of the highly active molecular manganese vanadium oxide WOC [Mn 4 V 4 O 17 (OAc) 3 ] 3- in aqueous acetonitrile solutions. Using density functional theory together with electrochemistry and IR-spectroscopy, we propose a sequential three-step activation mechanism including a one-electron oxidation of the catalyst from [Mn 2 3+ Mn 2 4+ ] to [Mn 3+ Mn 3 4+ ], acetate-to-water ligand exchange, and a second one-electron oxidation from [Mn 3+ Mn 3 4+ ] to [Mn 4 4+ ]. Analysis of several plausible ligand exchange pathways shows that nucleophilic attack of water molecules along the Jahn-Teller axis of the Mn 3+ centers leads to significantly lower activation barriers compared with attack at Mn 4+ centers. Deprotonation of one water ligand by the leaving acetate group leads to the formation of the activated species [Mn 4 V 4 O 17 (OAc) 2 (H 2 O)(OH)] - featuring one H 2 O and one OH ligand. Redox potentials based on the computed intermediates are in excellent agreement with electrochemical measurements at various solvent compositions. This intricate interplay between redox chemistry and ligand exchange controls the formation of the catalytically active species. These results provide key reactivity information essential to further study bio-inspired molecular WOCs and solid-state manganese oxide catalysts., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Exhaled breath analysis for early disease detection may provide a convenient method for painless and non-invasive diagnosis. In this work, a novel, compact and easy-to-use breath analyzer platform with a modular sensing chamber and direct breath sampling unit is presented. The developed analyzer system comprises a compact, low volume, temperature-controlled sensing chamber in three modules that can host any type of resistive gas sensor arrays. Furthermore, in this study three modular breath analyzers are explicitly tested for reproducibility in a real-life breath analysis experiment with several calibration transfer (CT) techniques using transfer samples from the experiment. The experiment consists of classifying breath samples from 15 subjects before and after eating a specific meal using three instruments. We investigate the possibility to transfer calibration models across instruments using transfer samples from the experiment under study, since representative samples of human breath at some conditions are difficult to simulate in a laboratory. For example, exhaled breath from subjects suffering from a disease for which the biomarkers are mostly unknown. Results show that many transfer samples of all the classes under study (in our case meal/no meal) are needed, although some CT methods present reasonably good results with only one class.

Background: Collagen cross-links contribute to the mechanical resilience of the intervertebral disc (IVD). UVA-light-activated riboflavin-induced collagen crosslinking (UVA-CXL) is a well-established and effective ophthalmological intervention that increases the mechanical rigidity of the collagen-rich corneal matrix in Keratoconus. This study explores the feasibility, safety and efficacy of translating this intervention in reinforcing the IVD., Methods: Annulus fibrosus (AF) cells were isolated from bovine IVDs and treated with different combinations of riboflavin (RF) concentrations (0.05-8 mM) and UVA light intensities (0.3-4 mW/cm2). Metabolic activity (resazurin assay), cell viability (TUNEL assay), and gene expression of apoptosis regulators C-FOS and PT5 were assessed immediately and 24 hours after treatment. Biomechanical effects of UVA-CXL on IVDs were measured by indentation analysis of changes in the instantaneous modulus and by peel-force delamination strength analysis of the AF prior and after treatment., Results: Different intensities of UVA did not impair the metabolic activity of AF cells. However, RF affected metabolic activity (p < 0.001). PT53 expression was similar in all RF conditions tested while C-FOS expression decreased 24 hours after treatment. Twenty-four hours after treatment, no apoptotic cells were observed in any condition tested. Biomechanical characterizations showed a significant increase in the annular peel strength of the UVA-CXL group, when compared to controls of UVA and RF alone (p < 0.05). UVA-CXL treated IVDs showed up to 152% higher (p < 0.001) instantaneous modulus values compared to the untreated control., Conclusion: This is the first study on UVA-CXL treatment of IVD. It induced significantly increased delamination strength and instantaneous modulus indentation values in intact IVD samples in a structure-function relationship. RF concentrations and UVA intensities utilized in ophthalmological clinical protocols were well tolerated by the AF cells. Our findings suggest that UVA-CXL may be a promising tool to reinforce the IVD matrix., Competing Interests: The authors have declared that no competing interests exist.

In spite of the enormous promise that polymeric carbon nitride (PCN) materials hold for various applications, the fabrication of high-quality, binder-free PCN films and electrodes has been a largely elusive goal to date. Here, we tackle this challenge by devising, for the first time, a water-based sol-gel approach that enables facile preparation of thin films based on poly(heptazine imide) (PHI), a polymer belonging to the PCN family. The sol-gel process capitalizes on the use of a water-soluble PHI precursor that allows formation of a non-covalent hydrogel. The hydrogel can be deposited on conductive substrates, resulting in formation of mechanically stable polymeric thin layers. The resulting photoanodes exhibit unprecedented photoelectrochemical (PEC) performance in alcohol reforming and highly selective (∼100 %) conversions with very high photocurrents (>0.25 mA cm -2 under 2 sun) down to <0 V vs. RHE. This enables even effective PEC operation under zero-bias conditions and represents the very first example of a 'soft matter'-based PEC system capable of bias-free photoreforming. The robust binder-free films derived from sol-gel processing of water-soluble PCN thus constitute a new paradigm for high-performance 'soft matter' photoelectrocatalytic systems and pave the way for further applications in which high-quality PCN films are required., (© 2021 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Aerosols are currently seen as one of the main transmission routes for SARS-CoV-2, but a comprehensive understanding of the processes and appropriate action/adaptation of protection concepts requires the exchange of information across interdisciplinary boundaries. Against this background, the Baden-Württemberg state government launched in October 2020 a multidisciplinary "Expert Group Aerosols" comprising engineers, natural scientists and medical professionals. In its statement, the group has compiled the current state of knowledge in all relevant disciplines in the context of airborne SARS-CoV-2 infection. In addition to the well-known hygiene and social distancing rules, the importance of the correct use of effective masks is emphasized. Furthermore, the necessity for dynamic and correct ventilation is pointed out and illustrated with ventilation intervals and periods for different scenarios as examples. The effectiveness of stationary or mobile cabin air filters as an important component in the protection concept is discussed. The first opinion of the expert group makes it clear that the existing hygiene and social distancing rules offer the best possible protection against SARS-CoV-2 infection only when correctly applied in combination., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

The exposure of mining workers to crystalline particles, e.g., alpha quartz in respirable dust, is a ubiquitous global problem in occupational safety and health at surface and underground operations. The challenge of rapid in-field monitoring for direct assessment and adoption of intervention has not been solved satisfactorily to date, as conventional analytical methods such as X-ray diffraction and infrared spectroscopy require laboratory environments, complex system handling, tedious sample preparation, and are limited by, e.g., addressable particle size. A novel monitoring approach was developed for potential in-field application enabling the quantification of crystalline particles in the respirable regime based on transmission infrared spectroscopy. This on-site approach analyzes samples of dust in ambient air collected onto PVC filters using respirable dust sampling devices. In the present study, we demonstrate that portable Fourier transform infrared (FT-IR) spectroscopy in combination with multivariate data analysis provides a versatile tool for the identification and quantification of minerals in complex real-world matrices. Without further sample preparation, the loaded filters are immediately analyzed via transmission infrared spectroscopy, and the mineral amount is quantified in real-time using a partial least squares regression algorithm. Due to the inherent molecular selectivity for crystalline as well as organic matrix components, infrared spectroscopy uniquely allows to precisely determine the particle composition even in complex samples such as dust from coal mines or clay-rich environments. For establishing a robust partial least squares regression model, a method was developed for generating calibration samples representative in size and composition for respirable mine dust via aerodynamic size separation. Combined with experimental design strategies, this allows tailoring the calibration set to the demands of air quality management in underground mining scenarios, i.e., the respirable particle size regime and the matrix of the target analyte.

In studies that target specific functions or organs, the response is often overlaid by indirect effects of the intervention on global metabolism. The metabolic side of these interactions can be assessed based on total energy expenditure (TEE) and the contributions of the principal energy sources, carbohydrates, proteins and fat to whole body CO 2 production. These parameters can be identified from indirect calorimetry using respiratory oxygen intake and CO 2 dioxide production data that are combined with the response of the 13 CO 2 release in the expired air and the glucose tracer enrichment in plasma following a 13 C glucose stable isotope infusion. This concept is applied to a mouse protocol involving anesthesia, mechanical respiration, a disease model, like hemorrhage and therapeutic intervention. It faces challenges caused by a small sample size for both breath and plasma as well as changes in metabolic parameters caused by disease and intervention. Key parameters are derived from multiple measurements, all afflicted with errors that may accumulate leading to unrealistic values. To cope with these challenges, a sensitive on-line breath analysis system based on substrate-integrated hollow waveguide infrared spectroscopy and luminescence (iHWG-IR-LS) was used to monitor gas exchange values. A Bayesian statistical model is developed that uses established equations for indirect calorimetry to predict values for respiratory gas exchange and tracer data that are consistent with the corresponding measurements and also provides statistical error bands for these parameters. With this new methodology, it was possible to estimate important metabolic parameters (respiratory quotient (RQ), relative contribution of carbohydrate, protein and fat oxidation f carb , f fat and f prot , total energy expenditure TEE) in a resolution never available before for a minimal invasive protocol of mice under anesthesia.