Recent progress and challenges on the bioassay of pathogenic bacteria.

The present review (containing 242 references) illustrates the importance and application of optical and electrochemical methods as well as their performance improvement using various methods for the detection of pathogenic bacteria. The application of advanced nanomaterials including hyper branched nanopolymers, carbon-based materials and silver, gold and so on. nanoparticles for biosensing of pathogenic bacteria was also investigated. In addition, a summary of the applications of nanoparticle-based electrochemical biosensors for the identification of pathogenic bacteria has been provided and their advantages, detriments and future development capabilities was argued. Therefore, the main focus in the present review is to investigate the role of nanomaterials in the development of biosensors for the detection of pathogenic bacteria. In addition, type of nanoparticles, analytes, methods of detection and injection, sensitivity, matrix and method of tagging are also argued in detail. As a result, we have collected electrochemical and optical biosensors designed to detect pathogenic bacteria, and argued outstanding features, research opportunities, potential and prospects for their development, according to recently published research articles.

DNA-based bioassay of legionella pneumonia pathogen using gold nanostructure: A new platform for diagnosis of legionellosis.

The specific diagnosis of hard-growing bacteria is one of the most important concerns of medical bacteriology. Legionella pneumophila is one of the most important bacteria in hard growth. In spite remarkable trends in bacteriology, now day, culture is the gold standard for detection of L. pneumophila. This work is an attempt to quantification of L. pneumophila bacteria using a bioassay. The fabrication of a new electrochemical DNA-based bioassay using gold nano architecture combined with as a transducer substrate combined with toluidine blue (TB) as a redox marker was performed successful. Also, the mixture of beta­cyclodextrin and dopamine as Poly (dopamine­ß­Cyclodextrin) was used to proper a biointerface for stabilization of gold nanoparticles optimum immobilize of pDNA sequence (5-SH-TCGA TAC TCT CCC CGC CCC TT T TGTATCGACG-3). So, a specific thiolated pDNA was immobilized on the transducer substrate and DNA hybridization was followed by C-DNA sequence (5-ACA AAA GGG GCG GGG AGA GTA-3) using square wave voltammetry and differential pulse voltammetry. At the optimum conditions, linear range was 1 µM to 1 ZM and low limit of quantification (LLOQ) was 1 Zepto-molar. L. pneumophila were sensitively distinguished by the planned DNA sensor. Finally, the engineered DNA based bioassay could be used for identifying the L. pneumophila samples from patients or environments.

The use of chitosan as a bioactive polysaccharide in non-invasive detection of malondialdehyde biomarker in human exhaled breath condensate: A new platform towards diagnosis of some lung disease.

Herein, a reusable and time-saving strategy for the electrochemical polymerization of dopamine (EPD) is reported. In this work, biocompatible polymer chitosan (CS) was electrodeposited on the surface of PDA modified glassy carbon electrode. Owing to the abundant catechol and amine groups in the PDA layer, uniform silver nanoparticles (Ag NPs) are deposited onto the POLY(DA-CS) and can effectively prevent the recombination of electron-hole pairs generated from photo-electrocatalysis and transfer the captured electrons to participate in the photo-electrocatalytic reaction process. Compared with pristine POLY(DA-CS), the as-prepared POLY(DA-CS)-AgNPs organic-inorganic hybrid exhibit electrochemical sensitivity for detecting MDA and display excellent durability. Furthermore, the mussel-inspired electropolymerization strategy and the fast EPD-Ag nanoparticle decorating process presented herein can be readily extended to various biomedical analysis and lung cancer detection. It is the adaptation of the established POLY(DA-CS)-Ag NPs organic-inorganic hybrid for a selective, robust, and generalizable sensing system that is the emphasis of this work.

A novel DNA based bioassay toward ultrasensitive detection of Brucella using gold nanoparticles supported histidine: A new platform for the assay of bacteria in the cultured and human biofluids with and without polymerase chain reactions (PCR).

Brucella organisms, which are small aerobic intracellular coccobacilli, localize in the reproductive organs of host animals, causing abortions and sterility. In this work, we used a novel method to preparation of excellent genosensor on the surface of low-toxic substrate (gold nanoparticles) supported histidine prepared by fully electrodeposition method. The results of the present work show that the nano-Au-Hist provide suitable active sites for the DNA probe immobilization. The fabricated DNA genosensor employs cyclic voltammetry (CV), and square wave voltammetry (SWV) techniques for monitoring the behavior of the redox probe. To survey the morphological pattern and surface structural characterizations, the Field Emission-Scanning Electron Microscopy (FE-SEM) has been applied. In summary, the gold nanoparticles supported by histidine was checked for immobilization of a Brucella-specific probe and detection of hybridization with a variety of sequences with a high sensitivity. The high sensitivity would be related to more favorable conformation and deflection angle of the probe for an efficient hybridization, higher surface concentration of the probe, and/or enhanced diffusion regime. These lead to better display of the entangled target sequences arising from the nanobiotechnology. The proposed genosensor showed a perfect distinction between complementary, non-complementary and mismatched DNA sequences. The engineered genosensor for detection of the complementary/non-complementary sequences were assayed. The fabricated genosensor was evaluated for the assay of the bacteria in the cultured and human samples with and without polymerase chain reactions (PCR). The genosensor could detect the complementary sequence in linear concentration range of 1 × 10-1 to 1 × 10-10 µM, and a low limit of quantification 0.1 pM.