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TiO2-facilitated MALDI–TOF-MS was proposed to improve intact bacteria fingerprinting, allowing rapid and convenient antimicrobial resistance-associated protein detection during bacteria identification., Titanium dioxide-modified target plates were developed to enhance intact bacteria analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The plates were designed to photocatalytically destroy the bacterial envelope structure and improve the ionization efficiency of intracellular components, thereby promoting the measurable mass range and the achievable detection sensitivity. Accordingly, a method for rapid detection of antimicrobial resistance-associated proteins, conferring bacterial resistance against antimicrobial drugs, was established by mass spectrometric fingerprinting of intact bacteria without the need for any sample pre-treatment. With this method, the variations in resistance proteins’ expression levels within bacteria were quickly measured from the relative peak intensities. This approach of resistance protein detection directly from intact bacteria by mass spectrometry is useful for fast discrimination of antimicrobial-resistant bacteria from their non-resistant counterparts whilst performing species identification. Also, it could be used as a rapid and convenient way for initial determination of the underlying resistance mechanisms.

An immunoaffinity mass spectrometry method was proposed for quick BSI diagnosis., Bloodstream infections rank among the most serious causes of morbidity and mortality in hospitalized patients, partly due to the long period (up to one week) required for clinical diagnosis. In this work, we have developed a sensitive method to quickly and accurately identify bacteria in human blood samples by combining optimized matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and efficient immunoaffinity enrichment/separation. A library of bacteria reference mass spectra at different cell numbers was firstly built. Due to a reduced sample spot size, the reference spectra could be obtained from as few as 10 to 102 intact bacterial cells. Bacteria in human blood samples were then extracted using antibodies-modified magnetic beads for MS fingerprinting. By comparing the sample spectra with the reference spectra based on a cosine correlation, bacteria with concentrations as low as 500 cells per mL in blood serum and 8000 cells per mL in whole blood were identified. The proposed method was further applied to positive clinical blood cultures (BCs) provided by a local hospital, where Escherichia coli and Staphylococcus aureus were identified. Because of the method’s high sensitivity, the BC time required for diagnosis can be greatly reduced. As a proof of concept, whole blood spiked with a low initial concentration (102 or 103 cells per mL) of bacteria was cultured in commercial BC bottles and analysed by the developed method after different BC times. Bacteria were successfully identified after 4 hours of BC. Therefore, an entire diagnostic process could be accurately accomplished within half a day using the newly developed method, which could facilitate the timely determination of appropriate anti-bacterial therapy and decrease the risk of mortality from bloodstream infections.

The one-step fabrication of gold films by inkjet printing of a gold precursor ink and its photochemical reduction by exposure to UV light is presented. Inkjet printing creates on a substrate with high control micrometer-thin reaction volumes in which upon direct high-intensity light irradiation, the gold precursor reduces to pure and well-adhered Au particles, while all other ink components escape in the gas phase, without the need for any further post-treatment. The Au precursor ink does neither contain stabilizing agents, such as polymers or surfactants, nor sacrificial compounds, such as photoinitiators, to initiate and accelerate the reduction. This economic and green process is known as Print-Light-Synthesis (PLS) and is herein used to create gold patterns of thin compact Au films and separated Au nanoparticles. Gold loadings are in the mu g cm(-2) range and precisely controlled, thanks to the inkjet printing parameters. The gold films are characterized by spectroscopic and electrochemical methods. Finally, the applicability of Au films as electrochemical sensors is demonstrated for the detection of 1,4-butanediol in comparison to a commercial screen-printed Au electrode. The PLS Au electrode shows a 20 times higher sensitivity and opens new possibilities for disposable electrode production.

Bloodstream infections rank among the most serious causes of morbidity and mortality in hospitalized patients, partly due to the long period (up to one week) required for clinical diagnosis. In this work, we have developed a sensitive method to quickly and accurately identify bacteria in human blood samples by combining optimized matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and efficient immunoaffinity enrichment/separation. A library of bacteria reference mass spectra at different cell numbers was firstly built. Due to a reduced sample spot size, the reference spectra could be obtained from as few as 10 to 102 intact bacterial cells. Bacteria in human blood samples were then extracted using antibodies-modified magnetic beads for MS fingerprinting. By comparing the sample spectra with the reference spectra based on a cosine correlation, bacteria with concentrations as low as 500 cells per mL in blood serum and 8000 cells per mL in whole blood were identified. The proposed method was further applied to positive clinical blood cultures (BCs) provided by a local hospital, where Escherichia coli and Staphylococcus aureus were identified. Because of the method’s high sensitivity, the BC time required for diagnosis can be greatly reduced. As a proof of concept, whole blood spiked with a low initial concentration (102 or 103 cells per mL) of bacteria was cultured in commercial BC bottles and analysed by the developed method after different BC times. Bacteria were successfully identified after 4 hours of BC. Therefore, an entire diagnostic process could be accurately accomplished within half a day using the newly developed method, which could facilitate the timely determination of appropriate anti-bacterial therapy and decrease the risk of mortality from bloodstream infections.

Herein, we present the intact cell matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the fingerprinting of human melanoma cancer cell lines grown on aluminium foil. To perform the MALDI-MS assay, melanoma cells were cultured on a flat and thin foil, which was directly transferred to the target plate of MALDI-MS for analysis. The influence of a wide range of cell fixation protocols (i.e. formalin-based and alcohol-based methods) and MALDI matrices on the obtained characteristic spectra was investigated. For the optimization of the MALDI-MS protocol, the MS fingerprints of the melanoma WM-239 cell line with and without an overexpressed enhanced green fluorescent protein were employed. The fingerprints obtained from WM-239 cells grown on aluminum foil were compared with intact cell MALDI of cell pellet and presented higher sensitivity in high m/z range. The optimized protocol was subsequently applied to characterise melanoma cell lines derived from different cancer stages and allowed the identification of unique MS signals that can be used for the differentiation between the studied cell lines (i.e. molecular weight equal to 10.0 kDa and 26.1 kDa).

The development of new biodegradable plastic materials from renewable sources is a major challenge for plastic industries to provide sustainable alternatives to petroleum plastic. Bio-based plastics are generally obtained from photosynthetic biomass such as higher plants, crops and more recently algae. This review aims to summarise the current state of bioplastic production in general with particular emphasis on algal cellulose and its derivatives (nanocellulose) for bioplastic applications. Despite the potential of algae as a feedstock for nanocellulose, little information is available on strain selection regarding cellulose content and downstream processing. This study lists possible optimization opportunities to increase the cellulose yield of algal biomass and the current status of its conversion to nanocellulose. Moreover, the findings of this review provide insight into existing knowledge and future direction in the algal cellulosic bioplastic domain based on algal bioplastic life cycle assessment studies. Finally, the review gives an overview of the main standards used for biodegradability certifications in view to limit the access to the biodegradable label when the required quality is not reached.

Inkjet printing of electrochemical sensors using a highly loaded mildly edge‐oxidized graphene nanosheet (EOGN) ink is presented. An ink with 30 mg/mL EOGNs is formulated in a mixture of N‐methyl pyrrolidone and propylene glycol with only 30 min of sonication. The absence of additives, such as polymeric stabilizers or surfactants, circumvents reduced electrochemical activity of coated particles and avoids harsh post‐printing conditions for additive removal. A single light pulse from a xenon flash lamp dries the printed EGON film within a fraction of a second and creates a compact electrode surface. An accurate coverage with only 30.4 μg of EOGNs per printed layer and cm2 is achieved. The EOGN films adhere well to flexible polyimide substrates in aqueous solution. Electrochemical measurements were performed using cyclic voltammetry and differential pulse voltammetry. An all inkjet‐printed three‐electrode living bacterial cell detector is prepared with EOGN working and counter electrodes and silver‐based quasi‐reference electrode. The presence of E. coli in liquid samples is recorded with four electroactive metabolic activity indicators.

Imaging samples on a surface by mass spectrometry (MS) requires the combination of MS detection with a scanning mode that enables localized desorption and ionization and/or detection of sample analytes with good spatial resolution. We have developed a new mass spectrometry imaging (MSI) method based on electrostatic spray ionization. It works under ambient conditions and can be applied to a wide range of molecules providing quantitative MS analysis even in the presence of salts in excess. 2D MS images of protein and peptide spots, inkjet-printed black dye patterns, and cells were obtained. The presented novel ambient ionization mass spectrometry imaging method can find many applications in analytical and bioanalytical chemistry.

Although tremendous progress has been made in the diagnosis of melanoma, the identification of different stages of malignancy in a reliable way remains challenging. Current strategies rely on optical monitoring of the concentration and spatial distribution of specific biomarkers. State-of-the-art optical methods can be affected by background-color interference and autofluorescence. We overcame these shortcomings by employing scanning electrochemical microscopy (SECM) to map the prognostic indicator tyrosinase (TyR) in non-metastatic and metastatic melanoma tissues by using soft-stylus microelectrodes. Electrochemical readout of the TyR distribution was enabled by adapting an immunochemical method. SECM can overcome the limitations of optical methods and opens unprecedented possibilities for improved diagnosis and understanding of the spatial distribution of TyR in different melanoma stages. Trotz des enormen Fortschritts, der bei der Diagnose von Melanomen erzielt wurde, bleibt die zuverlässige Erkennung der verschiedenen Malignomstadien eine Herausforderung. Derzeitige Strategien setzen auf die optische Erfassung der Konzentration und räumlichen Verteilung spezifischer Biomarker. Neueste optische Methoden können allerdings durch Interferenzen mit Hintergrundfarben und durch Autofluoreszenz beeinflusst werden. Wir bewältigen diese Defizite hier unter Einsatz der elektrochemischen Rastersondenmikroskopie (SECM), um den prognostischen Indikator Tyrosinase (TyR) in nicht‐metastatischen und metastatischen Melanomgeweben mithilfe einer weichen Mikroelektrodensonde abzubilden. Das elektrochemische Auslesen der TyR‐Verteilung wurde durch das Adaptieren eines immunchemischen Verfahrens ermöglicht. Wir zeigen, dass die SECM die erwähnten Beschränkungen optischer Methoden übertreffen kann und bisher nicht gekannte Möglichkeiten für eine verbesserte Diagnose und das Verständnis der räumlichen Verteilung von TyR in verschiedenen Melanomstadien eröffnet.

Skin problems are often overlooked due to a lack of robust and patient-friendly monitoring tools. Herein, we report a rapid, noninvasive, and high-throughput analytical chemical methodology, aiming at real-time monitoring of skin conditions and early detection of skin disorders. Within this methodology, adhesive sampling and laser desorption ionization mass spectrometry are coordinated to record skin surface molecular mass in minutes. Automated result interpretation is achieved by data learning, using similarity scoring and machine learning algorithms. Feasibility of the methodology has been demonstrated after testing a total of 117 healthy, benign-disordered, or malignant-disordered skins. Remarkably, skin malignancy, using melanoma as a proof of concept, was detected with 100% accuracy already at early stages when the lesions were submillimeter-sized, far beyond the detection limit of most existing noninvasive diagnosis tools. Moreover, the malignancy development over time has also been monitored successfully, showing the potential to predict skin disorder progression. Capable of detecting skin alterations at the molecular level in a nonsurgical and time-saving manner, this analytical chemistry platform is promising to build personalized skin care.