scholarly journals Photoluminescence-Based Bioassay With Cysteamine-Capped TiO2 Nanoparticles for the Selective Recognition of N-Acyl Homoserine Lactones

2021 ◽  
Vol 9 ◽  
Author(s):  
Sahana Vasudevan ◽  
Parthasarathy Srinivasan ◽  
Prasanna Neelakantan ◽  
John Bosco Balaguru Rayappan ◽  
Adline Princy Solomon
Keyword(s):  
Financial Burden ◽  
Intensity Variation ◽  
Diagnostic Procedures ◽  
Detection Range ◽  
Homoserine Lactones ◽  
Bacterial Signaling ◽  
Acyl Homoserine Lactones ◽  
Relative Response ◽  
Linear Detection ◽  
Microbial Infections

Currently available diagnostic procedures for infections are laborious and time-consuming, resulting in a substantial financial burden by increasing morbidity, increased costs of hospitalization, and mortality. Therefore, innovative approaches to design diagnostic biomarkers are imperative to assist in the rapid and sensitive diagnosis of microbial infections. Acyl homoserine lactones (AHLs) are ubiquitous bacterial signaling molecules that are found to be significantly upregulated in infected sites. In this pioneering work, we have developed a simple photoluminescence-based assay using cysteamine-capped titanium oxide (TiO2) nanoparticles for AHL detection. The PL intensity variation of the oxygen defect state of TiO2 was used for the biosensing measurements. The bioassays were validated using two well-studied AHL molecules (C4-HSL and 3-oxo-C12 HSL) of an important human pathogen, Pseudomonas aeruginosa. The developed system has a maximum relative response of 98%. Furthermore, the efficacy of the system in simulated host urine using an artificial urine medium showed a linear detection range of 10–160 nM. Also, we confirmed the relative response and specificity of the system in detecting AHLs produced by P. aeruginosa in a temporal manner.

scholarly journals Flexible and Printed Electrochemical Immunosensor Coated with Oxygen Plasma Treated SWCNTs for Histamine Detection

Biosensors ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 35 ◽  
Author(s):  
Bajramshahe Shkodra ◽  
Biresaw Demelash Abera ◽  
Giuseppe Cantarella ◽  
Ali Douaki ◽  
Enrico Avancini ◽  
...  
Keyword(s):  
Oxygen Plasma ◽  
Electrochemical Immunosensor ◽  
Coefficient Of Determination ◽  
Time Stability ◽  
Detection Range ◽  
Relative Response ◽  
Linear Detection ◽  
Fish Samples ◽  
Amino Acid Histidine ◽  
Walled Carbon Nanotubes

Heterocyclic amine histamine is a well-known foodborne toxicant (mostly linked to “scombroid poisoning”) synthesized from the microbial decarboxylation of amino acid histidine. In this work, we report the fabrication of a flexible screen-printed immunosensor based on a silver electrode coated with single-walled carbon nanotubes (SWCNTs) for the detection of histamine directly in fish samples. Biosensors were realized by first spray depositing SWCNTs on the working electrodes and by subsequently treating them with oxygen plasma to reduce the unwanted effects related to their hydrophobicity. Next, anti-histamine antibodies were directly immobilized on the treated SWCNTs. Histamine was detected using the typical reaction of histamine and histamine-labeled with horseradish peroxidase (HRP) competing to bind with anti-histamine antibodies. The developed immunosensor shows a wide linear detection range from 0.005 to 50 ng/mL for histamine samples, with a coefficient of determination as high as 98.05%. Average recoveries in fish samples were observed from 96.00% to 104.7%. The biosensor also shows good selectivity (less than 3% relative response for cadaverine, putrescine, and tyramine), reproducibility, mechanical and time stability, being a promising analytical tool for the analysis of histamine, as well as of other food hazards.

scholarly journals Human Paraoxonase-2 (PON2): Protein Functions and Modulation

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 256
Author(s):  
Giuseppe Manco ◽  
Elena Porzio ◽  
Teresa Maria Carusone
Keyword(s):  
Hydrolytic Activity ◽  
Principal Function ◽  
Substrate Specificities ◽  
Homoserine Lactones ◽  
Stress Control ◽  
Acyl Homoserine Lactones ◽  
Bacterial Quorum Sensing ◽  
Protein Functions ◽  
Bacterial Quorum ◽  
Hydrolyzing Enzymes

PON1, PON2, and PON3 belong to a family of lactone hydrolyzing enzymes endowed with various substrate specificities. Among PONs, PON2 shows the highest hydrolytic activity toward many acyl-homoserine lactones (acyl-HL) involved in bacterial quorum-sensing signaling. Accordingly, defense against pathogens, such as Brevundimonas aeruginosa (B. aeruginosa), was postulated to be the principal function of PON2. However, recent findings have highlighted the importance of PON2 in oxidative stress control, inhibition of apoptosis, and the progression of various types of malignancies. This review focuses on all of these aspects of PON2.

scholarly journals Sampling, separation, and quantification of N ‐acyl homoserine lactones from marine intertidal sediments

2021 ◽  
Vol 19 (2) ◽  
pp. 145-157
Author(s):  
Frederike Stock ◽  
Emilio Cirri ◽  
Samarasinghe Gunasekara Liyanage Is Nuwanthi ◽  
Willem Stock ◽  
Nico Ueberschaar ◽  
...  
Keyword(s):  
Intertidal Sediments ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones

scholarly journals Label-Free Electrochemical Biosensor Based on Au@MoS₂–PANI for Escherichia coli Detection

Chemosensors ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Pushap Raj ◽  
Man Hwan Oh ◽  
Kyudong Han ◽  
Tae Yoon Lee
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Bacterial Pathogens ◽  
Cost Effective ◽  
Covalent Immobilization ◽  
Label Free ◽  
Self Assembled Monolayer ◽  
Detection Range ◽  
Linear Detection

Bacterial infections have become a significant challenge in terms of public health, the food industry, and the environment. Therefore, it is necessary to address these challenges by developing a rapid, cost-effective, and easy-to-use biosensor for early diagnosis of bacterial pathogens. Herein, we developed a simple, label-free, and highly sensitive immunosensor based on electrochemical detection using the Au@MoS₂–PANI nanocomposite. The conductivity of the glassy carbon electrode is greatly enhanced using the Au@MoS₂–PANI nanocomposite and a self-assembled monolayer of mercaptopropionic acid on the gold nanoparticle surface was employed for the covalent immobilization of antibodies to minimize the nonspecific adsorption of bacterial pathogens on the electrode surface. The biosensor established a high selectivity and sensitivity with a low limit of detection of 10 CFU/mL, and detected Escherichia coli within 30 min. Moreover, the developed biosensor demonstrated a good linear detection range, practical utility in urine samples, and electrode regenerative studies.

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