Towards controlled and simple design of non-enzymatic amperometric sensor for glycerol determination in yeast fermentation medium.

Glycerol is a widely used signaling bioanalyte in biotechnology. Glycerol can serve as a substrate or product of many metabolic processes in cells. Therefore, quantification of glycerol in fermentation samples with inexpensive, reliable, and rapid sensing systems is of great importance.

One-step electrodeposited hybrid nanofilms in amperometric biosensor development.

This review summarizes recent developments in amperometric biosensors, based on one-step electrodeposited organic-inorganic hybrid layers, used for analysis of low molecular weight compounds. The factors affecting self-assembly of one-step electrodeposited films, methods for verifying their composition, advantages, limitations and approaches affecting the electroanalytical performance of amperometric biosensors based on organic-inorganic hybrid layers were systemized. Moreover, issues related to the formation of one-step organic-inorganic hybrid functional layers with different structures in biosensors produced under the same electrodeposition parameters are discussed.

A rapid in vitro electrochemical screening of extracellular matrix of Saccharomyces cerevisiae by palladium nanoparticles-modified electrodes.

Herein, a rapid electrochemical screening of yeasts (Saccharomyces cerevisiae) in vitro mode depending on their optical density, cultivation time and growth medium used was conducted in 3 min by palladium nanoparticles (Pd-NPs)-modified electrodes. Pd-NPs-modified electrodes operated in cyclic voltammetry mode at low scan rates, i.e.

modulation of enzyme activity heterogeneous catalysis utilizing solid electroplated cofactors.

During product isolation the received bioreceptors often do not exhibit a sufficient biochemical activity due to multistep dissociation and loss of cofactors. However, for bioelectrochemical applications the presence of cofactors is necessary for a successful oxidative or reductive conversion of the substrates to the products. Herein, we show how the immobilization of the required electroplated cofactors in a design of amperometric electrodes can assist the activity of apo-enzymes.

The development of alginate-based amperometric nanoreactors for biochemical profiling of living yeast cells.

This study describes the development of a one-pot electrochemical miniaturized system for simultaneous cultivation and monitoring of the oxidative status of living cells. This system consisted of screen-printed electrodes modified by electroplated Pd-NPs as an electrocatalyst (i) and living yeast cells (Saccharomyces cerevisiae) (ii) immobilized on the cytocompatible alginate layer (iii). Briefly, during the course of electrochemical investigations a novel electroactive compound methylhydrazine derivative as a secondary metabolite and result of microbial activity was found in yeast cells and used as a signaling molecule for their biochemical profiling.

Toward Alginate-Based Membrane Technology for High Performance Recovery of Heavy Metals in Cells.

One of the major environmental problems is a global metal contamination. Heavy metals are nonbiodegradable and tend to accumulate in living organisms. Therefore, searching for biocompatible materials with enhanced sorption capabilities for selective removal of toxic elements from complex environments, low cost, ease of operation, and large available quantities that meet all requirements of the Green Chemistry concept is a current engineering and analytical task.

Electrochemical operational principles and analytical performance of Pd-based amperometric nanobiosensors.

Palladium nanoparticles (Pd-NPs) have been approved as an effective catalyst for hydrogen peroxide decomposition which is released during specific enzymatic reactions. However, the general operational principles and electrochemical performance of Pd-NPs-based nanobiosensors have been poorly exploited. Here, the electrochemical behavior of oxidase-associated peroxide oxidation co-catalysis of the modelled microanalytical system based on screen-printed electrodes modified by electroplated Pd-NPs as an electrocatalyst, glucose oxidase (GOx) or alcohol oxidase (AOx) as a bioreceptor and the ionomer Nafion as a polymeric binding agent was studied in detail.

A novel copper (II) binding peptide for a colorimetric biosensor system design.

Filamentous bacteriophages are viruses infecting only bacteria. In this study, phage display technique was applied to identify highly selective Cu(II) binding peptides. After five rounds of positive screening against Cu(II) and various rounds of negative screenings against competitive metal ions (Al(III), Co(II), Fe(III), Ni(II) and Zn(II)), bacteriophages were enriched.

Mechanistic aspects of functional layer formation in hybrid one-step designed GOx/Nafion/Pd-NPs nanobiosensors.

Amperometric nanobiosensors are crucial time and cost effective analytical tools for the detection of a wide range of bioanalytes, viz. glucose present in complex environments at very low concentrations. Although the excellent analytical performance of nanobiosensors is undoubted, their exact molecular structure often remains unclear.

LDI-MS scanner: Laser desorption ionization mass spectrometry-based biosensor standardization.

Amperometric biosensors have been widely utilized for the cost-effective and rapid analysis of various bioanalytes, for example glucose. However, a lack of standardization and validation procedures remains a major limitation in biosensor development. Therefore, despite rapid advances in material science driving the development of amperometric biosensors, to date only a few biosensors, detecting a limited range of analytes, are available on the market.

Automated Electrochemical Glucose Biosensor Platform as an Efficient Tool Toward On-Line Fermentation Monitoring: Novel Application Approaches and Insights.

Monitoring and control of fermentation processes remain a crucial challenge for both laboratory and industrial-scale experiments. Reliable identification and quantification of the key process parameters in on-line mode allow operation of the fermentation at optimal reactor efficiency, maximizing productivity while minimizing waste. However, state-of-the-art fermentation on-line monitoring is still limited to a number of standard measurements such as pH, temperature and dissolved oxygen, as well as off-gas analysis as an advanced possibility.

Towards one-step design of tailored enzymatic nanobiosensors.

The manufacturing of conventional enzymatic biosensors produced via a layer-by-layer (LbL) approach requires expensive instrumentation, and in most cases involves a complex, resource and time-consuming fabrication process. Moreover, LbL assemblies are prone to mechanical instability that leads to irreversible changes in sensor architecture and morphology resulting in degradation of enzymatic activities and insufficient signal reproducibility. Hence, novel fabrication techniques for the production of enzymatic biosensors that are instrumentally controlled and allow reproducible, simultaneous multi-analyte detection with high specificity, temporal and spatial resolution are greatly required.

The Role of Nanoanalytics in the Development of Organic-Inorganic Nanohybrids-Seeing Nanomaterials as They Are.

The functional properties of organic-inorganic (O-I) hybrids can be easily tuned by combining system components and parameters, making this class of novel nanomaterials a crucial element in various application fields. Unfortunately, the manufacturing of organic-inorganic nanohybrids still suffers from mechanical instability and insufficient synthesis reproducibility. The control of the composition and structure of nanosurfaces themselves is a specific analytical challenge and plays an important role in the future reproducibility of hybrid nanomaterials surface properties and response.

One-step encapsulation, storage and controlled release of low molecular weight organic compounds via electroplated nanoparticles.

Herein, we introduce an original strategy toward one-step encapsulation, storage and controlled release of low molecular weight organic compounds via electroplated nanoparticles. This concept is demonstrated on the basis of the encapsulation of several organic matrices typically used for matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) as a case study via co-deposition with palladium nanoparticles (Pd-NPs). Remarkably, Pd-NPs act as a capsule for MALDI matrices and thus provide their controlled release depending on the external factors, viz.

Sensors for biosensors: a novel tandem monitoring in a droplet towards efficient screening of robust design and optimal operating conditions.

Understanding the biorecognition and transduction mechanisms is a key aspect in the development of robust sensing technologies. Therefore, the design of tools and analytical approaches that could allow gaining a deeper insight into the bio- and electrochemical processes would significantly accelerate the progress in the field of biosensors. Herein, we present a novel effective strategy for biosensor design screening based on tandem monitoring of individual system parameters in a droplet.

Exploring the potential of electroless and electroplated noble metal-semiconductor hybrids within bio- and environmental sensing.

Over the last two decades, the rapid development and widespread application of nanomaterials has significantly influenced research in various fields, including analytical chemistry and biosensing technologies. In particular, the simple functionalization and tuning of noble metal nanoparticle (NP) surface chemistry resulted in the development of a series of novel biosensing platforms with quick read-out and enhanced capabilities towards specific analyte detection. Moreover, noble metal NPs possess a number of unique properties, viz.

Storage and controlled release of fragrances maintaining a constant ratio of volatile compounds.

Controlled fragrance release at the right time, in the right place, depending on the context remains a technological challenge in the areas of psychophysiology, biochemistry and the entertainment industry. In this study, we demonstrate how bulk poly(dimethylsiloxane) (PDMS) templates may effectively take up and retain volatile organic compounds of essential orange oil in the original form without significantly shifting the scent profile. This is done depending on the sampling approach that follows a controllable and slow fragrance release maintaining a constant ratio of volatile compounds in a template-thickness, temperature and time-dependent manner.

A study of enhanced ion formation from metal-semiconductor complexes in atmospheric pressure laser desorption/ionization mass spectrometry.

The study of the key parameters impacted surface-assisted laser desorption/ionization-mass spectrometry is of broad interest. In previous studies, it has been shown that surface-assisted laser desorption/ionization-mass spectrometry is a complex process depending on multiple factors. In the presented study, we showed that neither porosity, light absorbance nor surface hydrophobicity alone influence the enhancement phenomena observed from the hybrid metal-semiconductor complexes versus individual targets, but small changes in the analyte attaching to the target significantly affect laser desorption ionization-efficiency.

Penetration of CdSe/ZnS quantum dots into differentiated vs undifferentiated Caco-2 cells.

Background: Quantum dots (QDs) have great potential as fluorescent labels but cytotoxicity relating to extra- and intracellular degradation in biological systems has to be addressed prior to biomedical applications. In this study, human intestinal cells (Caco-2) grown on transwell membranes were used to study penetration depth, intracellular localization, translocation and cytotoxicity of CdSe/ZnS QDs with amino and carboxyl surface modifications. The focus of this study was to compare the penetration depth of QDs in differentiated vs undifferentiated cells using confocal microscopy and image processing.

Interactions between DPPC as a component of lung surfactant and amorphous silica nanoparticles investigated by HILIC-ESI-MS.

This paper reports a rapid HILIC-ESI-MS assay to quantify dipalmitoylphosphatidylcholine (DPPC) as component of lung surfactant for nanosafety studies. The technique was used to investigate the concentration-dependent sorption of DPPC to two-sizes of amorphous SiO2 nanoparticles (SiO2-NPs) in a MeOH:H2O (50/50v/v) mixture and in cell culture medium. In MeOH:H2O (50/50v/v), the sorption of DPPC was positively correlated with the nanoparticles concentration.

p-Coumaric acid, a novel and effective biomarker for quantifying hypoxic stress by HILIC-ESI-MS.

In this study, we report p-coumaric acid as novel and effective response marker for indirectly measuring the levels of hypoxia in normal primary bronchial epithelial cells. We developed a simple and rapid technique based on hydrophilic interaction chromatography-electrospray ionization-mass spectrometry (HILIC-ESI-MS). During 168h of hypoxia without induction of reactive oxygen species (ROS), an almost linear increase of p-coumaric acid levels was observed.

Influence of surface melting effects and availability of reagent ions on LDI-MS efficiency after UV laser irradiation of Pd nanostructures.

In this study, the influence of surface morphology, reagent ions and surface restructuring effects on atmospheric pressure laser desorption/ionization (LDI) for small molecules after laser irradiation of palladium self-assembled nanoparticular (Pd-NP) structures has been systematically studied. The dominant role of surface morphology during the LDI process, which was previously shown for silicon-based substrates, has not been investigated for metal-based substrates before. In our experiments, we demonstrated that both the presence of reagent ions and surface reorganization effects--in particular, melting--during laser irradiation was required for LDI activity of the substrate.

Sorption of hydrophilic dyes on anodic aluminium oxide films and application to pH sensing.

The sorption of selected hydrophilic pH-sensitive dyes (bromophenol blue, bromothymol blue, bromocresol purple, alizarin red, methyl orange, congo red, rhodamine 6G) on films of anodized aluminium oxide (AAO) was investigated in this study. Depth and pore structure of the AAO channels were adjusted by changing electrolysis time and current density during treatment of aluminium foil in oxalic acid, sulfosalycilic acid and sulfuric acid at concentration levels between 0.2 and 0.

The role of physical and chemical properties of Pd nanostructured materials immobilized on inorganic carriers on ion formation in atmospheric pressure laser desorption/ionization mass spectrometry.

Fundamental parameters influencing the ion-producing efficiency of palladium nanostructures (nanoparticles [Pd-NP], nanoflowers, nanofilms) during laser irradiation were studied in this paper. The nanostructures were immobilized on the surface of different solid inorganic carrier materials (porous and mono-crystalline silicon, anodic porous aluminum oxide, glass and polished steel) by using classical galvanic deposition, electroless local deposition and sputtering. It was the goal of this study to investigate the influence of both the nanoparticular layer as well as the carrier material on ion production for selected analyte molecules.