Redesign of the Chlamydomonas reinhardtii Q binding niche reveals photosynthesis works in the absence of a driving force for Q-Q electron transfer.

An in silico redesign of the secondary quinone electron acceptor (Q) binding pocket of the D1 protein of Photosystem II (PSII) suggested that mutations of the F265 residue would affect atrazine binding. Chlamydomonas reinhardtii mutants F265T and F265S were produced to obtain atrazine-hypersensitive strains for biosensor applications, and the mutants were indeed found to be more atrazine-sensitive than the reference strain IL. Fluorescence and thermoluminescence data agree with a weak driving force and confirm slow electron transfer but cannot exclude an additional effect on protonation of the secondary quinone.

An All-Green Photo-Electrochemical Biosensor Using Microalgae Immobilized on Eco-Designed Lignin-Based Screen-Printed Electrodes to Detect Sustainable Nanoherbicides.

Herein, a novel completely green biosensor was designed exploiting both the biological and instrumental components made of eco-friendly materials for the detection of herbicides encapsulated into biodegradable nanoparticles for a sustainable agriculture. Similar nanocarriers, indeed, can deliver herbicides to the correct location, reducing the amount of active chemicals deposited in the plant, impacting the agricultural and food industries less. However, handling measurements of nanoherbicides is crucial to provide comprehensive information about their status in the agricultural fields to support farmers in decision-making.

Electrochemical Immunosensor for the Determination of Antibodies against Prostate-Specific Antigen Based on ZnO Nanostructures.

In this study, ZnO nanostructures with different types of morphologies and particle sizes were evaluated and applied for the development of an immunosensor. The first material was composed of spherical, polydisperse nanostructures with a particle size in the range of 10-160 nm. The second was made up of more compact rod-like spherical nanostructures with the diameter of these rods in the range of 50-400 nm, and approximately 98% of the particles were in the range of 20-70 nm.

Last Trends in Point-of-Care (POC) Diagnostics for the Management of Hematological Indices in Home Care Patients.

Today, complete blood count (CBC) analyses are highly automated and allow for high throughput and accurate and reliable results. However, new analytical tools are in great demand to provide simple, rapid and cost-effective management of hematological indices in home care patients. Chronic disease monitoring at home has become a benefit for patients who are finding cost savings in programs designed to monitor/treat patients in offsite locations.

Investigation of Photosystem II Functional Size in Higher Plants under Physiological and Stress Conditions Using Radiation Target Analysis and Sucrose Gradient Ultracentrifugation.

The photosystem II (PSII) reaction centre is the critical supramolecular pigment-protein complex in the chloroplast which catalyses the light-induced transfer of electrons from water to plastoquinone. Structural studies have demonstrated the existence of an oligomeric PSII. We carried out radiation inactivation target analysis (RTA), together with sucrose gradient ultracentrifugation (SGU) of PSII, to study the functional size of PSII in diverse plant species under physiological and stress conditions.

A Proof-of-Concept Electrochemical Cytosensor Based on Functionalized Carbon Black Screen-Printed Electrodes: Detection of in Wastewater as a Case Study.

Herein, we report a proof-of-concept algal cytosensor for the electrochemical quantification of bacteria in wastewater, exploiting the green photosynthetic alga immobilized on carbon black (CB) nanomodified screen-printed electrodes. The CB nanoparticles are used as nanomodifiers, as they are able to sense the oxygen produced by the algae and thus the current increases when algae are exposed to increasing concentrations of bacteria. The sensor was tested on both standard solutions and real wastewater samples for the detection in a linear range of response from 100 to 2000 CFU/100 mL, showing a limit of detection of 92 CFU/100 mL, in agreement with the maximum E.

MXene nanoflakes decorating ZnO tetrapods for enhanced performance of skin-attachable stretchable enzymatic electrochemical glucose sensor.

Continuous painless glucose monitoring is the greatest desire of more than 422 million diabetics worldwide. Therefore, new non-invasive and convenient approaches to glucose monitoring are more in demand than other tests for microanalytical diagnostic tools. Besides, blood glucose detection can be replaced by continuous glucose monitoring of other human biological fluids (e.

Innovative Eco-Friendly Conductive Ink Based on Carbonized Lignin for the Production of Flexible and Stretchable Bio-Sensors.

In this study, we report a novel way to produce carbon-based conductive inks for electronic and sensor technology applications. Carbonized lignin, obtained from the waste products of the tree paper industry, was used to produce a stable conductive ink. To this end, liquid-phase compositions were tested with different amounts of carbonized lignin powder to obtain an ink with optimal conductivity and rheological properties for different possible uses.

Photoautotrophs-Bacteria Co-Cultures: Advances, Challenges and Applications.

Photosynthetic microorganisms are among the fundamental living organisms exploited for millennia in many industrial applications, including the food chain, thanks to their adaptable behavior and intrinsic proprieties. The great multipotency of these photoautotroph microorganisms has been described through their attitude to become biofarm for the production of value-added compounds to develop functional foods and personalized drugs. Furthermore, such biological systems demonstrated their potential for green energy production (e.

A dual electro-optical biosensor based on Chlamydomonas reinhardtii immobilised on paper-based nanomodified screen-printed electrodes for herbicide monitoring.

The indiscriminate use of herbicides in agriculture contributes to soil and water pollution, with important endangering consequences on the ecosystems. Among the available analytical systems, algal biosensors have demonstrated to be valid tools thanks to their high sensitivity, cost-effectiveness, and eco-design. Herein, we report the development of a dual electro-optical biosensor for herbicide monitoring, based on Chlamydomonas reinhardtii whole cells immobilised on paper-based screen-printed electrodes modified with carbon black nanomaterials.

Quantum dots functionalised artificial peptides bioinspired to the D1 protein from the Photosystem II of Chlamydomonas reinhardtii for endocrine disruptor optosensing.

Herein we describe the design and synthesis of novel artificial peptides mimicking the plastoquinone binding niche of the D1 protein from the green photosynthetic alga Chlamydomonas reinhardtii, also able to bind herbicides. In particular, molecular dynamics (MD) simulations were performed to model in silico the behaviour of three peptides, D1Pep70-H, D1Pep70-S264K and D1Pep70-S268C, as genetic variants with different affinity towards the photosynthetic herbicide atrazine. Then the photosynthetic peptides were functionalised with quantum dots for the development of a hybrid optosensor for the detection of atrazine, one of the most employed herbicides for weed control in agriculture as well as considered as a putative endocrine disruptor case study.

High-Tech and Nature-Made Nanocomposites and Their Applications in the Field of Sensors and Biosensors for Gas Detection.

Gas sensors have been object of increasing attention by the scientific community in recent years. For the development of the sensing element, two major trends seem to have appeared. On one hand, the possibility of creating complex structures at the nanoscale level has given rise to ever more sensitive sensors based on metal oxides and metal-polymer combinations.

A microbial sensor platform based on bacterial bioluminescence (luxAB) and green fluorescent protein (gfp) reporters for in situ monitoring of toxicity of wastewater nitrification process dynamics.

To avoid the upset of nitrification process in wastewater treatment plants, monitoring of influent toxic chemicals is essential for stable operation. Toxic chemical compounds can interfere with the biological nitrogen removal, thus affecting plant efficiency and effluent water quality. Here we report the development of fluorescence and bioluminescence bioassays, based on E.

Novel atrazine-binding biomimetics inspired to the D1 protein from the photosystem II of Chlamydomonas reinhardtii.

Biomimetic design represents an emerging field for improving knowledge of natural molecules, as well as to project novel artificial tools with specific functions for biosensing. Effective strategies have been exploited to design artificial bioreceptors, taking inspiration from complex supramolecular assemblies. Among them, size-minimization strategy sounds promising to provide bioreceptors with tuned sensitivity, stability, and selectivity, through the ad hoc manipulation of chemical species at the molecular scale.

Electrospray deposition as a smart technique for laccase immobilisation on carbon black-nanomodified screen-printed electrodes.

Enzymes immobilisation represents a critical issue in the design of biosensors to achieve standardization as well as suitable analytical performances in terms of sensitivity, selectivity, and stability. In this work electrospray deposition (ESD) has been exploited as a novel technique for the immobilisation of laccase enzyme on carbon black modified screen-printed electrodes. The aim is to fabricate an amperometric biosensor for phenolic compound detection.

ZnO/polyaniline composite based photoluminescence sensor for the determination of acetic acid vapor.

In this study, we report a novel ZnO/polyaniline (PANI) nanocomposite optical gas sensor for the determination of acetic acid at room temperatures. ZnO nanorods, synthesized in powder form were coated by PANI (ZnO/PANI) by chemical polymerization method. The obtained nanocomposites were deposited on glass substrate and dried overnight at room temperature.

Fast pesticide pre-screening in marine environment using a green microalgae-based optical bioassay.

The present study evaluates an optical bioassay based on green photosynthetic microalgae as a promising alternative for monitoring of relevant seawater pollutants. Photosystem II fluorescence parameters from several microalgae species were examined in the presence of three common marine pesticides that act as photosynthesis inhibitors. The three pollutants were detected within 10 min in concentrations between ng/L-μg/L.

Better together: Strategies based on magnetic particles and quantum dots for improved biosensing.

Novel technologies and strategies for sensitive detection of biological responses in healthcare, food and environmental monitoring continue to be a priority. The present review focuses on bioassay development based on the simultaneous use of quantum dots and magnetic beads. Due to the outstanding characteristics of both particles for biosensing applications and the large number of publications using a combined approach, we aim to provide a comprehensive overview of the literature on different bioassays, the most recent advances and innovative strategies on the topic, together with an analysis of the main drawbacks encountered and potential solutions offered, with a special emphasis on the requirements that the transfer of technologies from the laboratory to the market will demand for future commercialization of biodevices.

The plastoquinol-plastoquinone exchange mechanism in photosystem II: insight from molecular dynamics simulations.

In the photosystem II (PSII) of oxygenic photosynthetic organisms, the reaction center (RC) core mediates the light-induced electron transfer leading to water splitting and production of reduced plastoquinone molecules. The reduction of plastoquinone to plastoquinol lowers PSII affinity for the latter and leads to its release. However, little is known about the role of protein dynamics in this process.

Preventive or potential therapeutic value of nutraceuticals against ionizing radiation-induced oxidative stress in exposed subjects and frequent fliers.

Humans are constantly exposed to ionizing radiation deriving from outer space sources or activities related to medical care. Absorption of ionizing radiation doses over a prolonged period of time can result in oxidative damage and cellular dysfunction inducing several diseases, especially in ageing subjects. In this report, we analyze the effects of ionizing radiation, particularly at low doses, in relation to a variety of human pathologies, including cancer, and cardiovascular and retinal diseases.

Design and biophysical characterization of atrazine-sensing peptides mimicking the Chlamydomonas reinhardtii plastoquinone binding niche.

The plastoquinone (Q(B)) binding niche of the Photosystem II (PSII) D1 protein is the subject of intense research due to its capability to bind also anthropogenic pollutants. In this work, the Chlamydomonas reinhardtii D1 primary structure was used as a template to computationally design novel peptides enabling the binding of the herbicide atrazine. Three biomimetic molecules, containing the Q(B)-binding site in a loop shaped by two α-helices, were reconstituted by automated protein synthesis, and their structural and functional features deeply analysed by biophysical techniques.

Mutations of photosystem II D1 protein that empower efficient phenotypes of Chlamydomonas reinhardtii under extreme environment in space.

Space missions have enabled testing how microorganisms, animals and plants respond to extra-terrestrial, complex and hazardous environment in space. Photosynthetic organisms are thought to be relatively more prone to microgravity, weak magnetic field and cosmic radiation because oxygenic photosynthesis is intimately associated with capture and conversion of light energy into chemical energy, a process that has adapted to relatively less complex and contained environment on Earth. To study the direct effect of the space environment on the fundamental process of photosynthesis, we sent into low Earth orbit space engineered and mutated strains of the unicellular green alga, Chlamydomonas reinhardtii, which has been widely used as a model of photosynthetic organisms.

A powerful molecular engineering tool provided efficient Chlamydomonas mutants as bio-sensing elements for herbicides detection.

This study was prompted by increasing concerns about ecological damage and human health threats derived by persistent contamination of water and soil with herbicides, and emerging of bio-sensing technology as powerful, fast and efficient tool for the identification of such hazards. This work is aimed at overcoming principal limitations negatively affecting the whole-cell-based biosensors performance due to inadequate stability and sensitivity of the bio-recognition element. The novel bio-sensing elements for the detection of herbicides were generated exploiting the power of molecular engineering in order to improve the performance of photosynthetic complexes.

Towards an integrated biosensor array for simultaneous and rapid multi-analysis of endocrine disrupting chemicals.

In this paper we propose the construction and application of a portable multi-purpose biosensor array for the simultaneous detection of a wide range of endocrine disruptor chemicals (EDCs), based on the recognition operated by various enzymes and microorganisms. The developed biosensor combines both electrochemical and optical transduction systems, in order to increase the number of chemical species which can be monitored. Considering to the maximum residue level (MRL) of contaminants established by the European Commission, the biosensor system was able to detect most of the chemicals analysed with very high sensitivity.

A photosynthetic biosensor with enhanced electron transfer generation realized by laser printing technology.

One of the limits of current electrochemical biosensors is a lack of methods providing stable and highly efficient junctions between biomaterial and solid-state devices. This paper shows how laser-induced forward transfer (LIFT) can enable efficient electron transfer from photosynthetic biomaterial immobilized on screen-printed electrodes (SPE). The ideal pattern, in terms of photocurrent signal of thylakoid droplets giving a stable response signal with a current intensity of approximately 335 ± 13 nA for a thylakoid mass of 28 ± 4 ng, was selected.