A cell-based potentiometric biosensor using the fungus Lentinus sajor-caju for permethrin determination in treated wood

An ultrasensitive solid-state electrochemiluminescence sensor based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2 for determination of permethrin

The novel TiO2 and Ni-MOF materials were synthesized and utilized for the detection of permethrin (PET). A highly sensitive solid-state electrochemiluminescence (ECL) sensor was developed based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2. In this sensing platform, Ru(bpy)32+-Tripropyl Amine (TPrA) was used as a luminescent signal, Ni-MOF acted as a carrier to carry more luminescent reagents Ru(bpy)32+. Au NPs acted as promoters facilitated electron transport and TiO2 could further enhance the luminescence intensity of the system by synergistical interaction with Au NPs. The possible mechanisms of signal amplification were investigated. The ECL intensity decreased significantly with increasing PET concentration, enabling the determination of PET amount through the observation of the change in ECL signal intensity (ΔI). Under optimal experimental conditions, the linear range of PET concentration from 1.0 × 10-11 mol L-1 to 1.0 × 10-6 mol L-1, with a detection limit of 3.3 × 10-12 mol L-1 (3S/N). This method was successfully applied to determine PET in various vegetable samples.

Enhancing electrochemiluminescence by modifying Fe3CuO4 and CdS@ZnS: A novel ECL sensor for highly sensitive detection of permethrin

A novel electrochemiluminescence (ECL) sensor was constructed for the detection of permethrin by modifying Fe3CuO4-Ru(bpy)32+ and GO-CdS@ZnS on the electrode. Fe3CuO4 was used as a carrier to adsorb more luminous reagent Ru(bpy)32+ to promote luminescence. Meanwhile, it also can be used as a co-reaction promoter to amplify the initial signal of Ru(bpy)32+-tri-n-propylamine (TPrA) system. When GO-CdS@ZnS was introduced into this system, the ECL signal was further enhanced. The porous nature of graphene oxide (GO) was utilized to load a large amount of CdS@ZnS, in which CdS@ZnS acted as the co-reactant to amplify the ECL signal. The amount of permethrin (PMT) increased and the ECL signal decreased. Under the optimum conditions, the ECL response was linearly related to the logarithm of PMT concentration. The developed ECL sensor allowed for sensitive determination of PMT and exhibited a wide linear range from 1.0 × 10-11 mol L-1 to 1.0 × 10-7 mol L-1. The limit of detection was 3.3 × 10-12 mol L-1 (S/N = 3). It can be used for the detection of PMT in vegetable samples.

Biosensors for Fungal Detection

Due to the serious threat of invasive fungal infections, there is an emergent need for improved a sensitive and more accurate diagnostic tests for detection of systemic pathogenic fungi and plant health. Traditional fungal diagnosis can only be achieved at later growing phases. The complex and difficult immunodiagnostic is also widely employed. Enzyme-based immunoassays which lead to cross-interaction with different fungi still also obeyed. A polymerase chain reactions (PCRs)- based molecular diagnosis are does not enable precise identification of fungal pathogens, or the ability to test isolates for drug sensitivity. In the future, biosensing technologies and nanotechnological tools, will improve diagnosis of pathogenic fungi through a specific and sensitive pathogen detection. This report systematically reviews the most prominent biosensor trends for fungi detection.

Fungal disease detection in plants: Traditional assays, novel diagnostic techniques and biosensors

Fungal diseases in commercially important plants results in a significant reduction in both quality and yield, often leading to the loss of an entire plant. In order to minimize the losses, it is essential to detect and identify the pathogens at an early stage. Early detection and accurate identification of pathogens can control the spread of infection. The present article provides a comprehensive overview of conventional methods, current trends and advances in fungal pathogen detection with an emphasis on biosensors. Traditional techniques are the "gold standard" in fungal detection which relies on symptoms, culture-based, morphological observation and biochemical identifications. In recent times, with the advancement of biotechnology, molecular and immunological approaches have revolutionized fungal disease detection. But the drawback lies in the fact that these methods require specific and expensive equipments. Thus, there is an urgent need for rapid, reliable, sensitive, cost effective and easy to use diagnostic methods for fungal pathogen detection. Biosensors would become a promising and attractive alternative, but they still have to be subjected to some modifications, improvements and proper validation for on-field use.

Micropatterning of 3D Microenvironments for Living Biosensor Applications

Micro-scale printing and patterning of living cells has multiple applications including tissue engineering, cell signaling assays, and the fabrication of cell-based biosensors. In this work, a molecular printing instrument, the Bioforce Nano eNabler, was modified to enable micron-scale -quill-pen based printing of mammalian cells in a 3D hyaluronan/gelatin based hydrogel. Specifically, photo-initiated -thiol-ene click chemistry was used to couple the thiol groups of thiolated hyaluronan/thiolated gelatin to the alkene groups of 4-arm polyethylene glycol (PEG)-norbornene molecules. Rapid photopolymerization enabled direct printing and controlled curing of living cells within the hydrogel matrix. The resulting hydrogels were biocompatible with human adipose-derived stem cells, NIH-3T3 cells, and mouse embryonic stem cells. The utility of this printing approach was also explored for cell-based biosensors. Micro-printed cells expressing a redox sensitive variant of the green fluorescent protein (roGFP-R12) showed a measurable fluorescent response to addition of oxidizing and then reducing agents. This work represents a novel approach to micron-scale cell patterning, and its potential for living, cell-based biosensors.