Development of an Electrogenerated Chemiluminescence Biosensor using Carboxylic acid-functionalized MWCNT and Au Nanoparticles

A COOH-F-MWCNT-Nafion-Ru(bpy)32+-Au-ADH electrogenerated chemiluminescence (ECL) electrode using COOH-functionalized MWCNT (COOH-F-MWCNT) and Au nanoparticles synthesized by the radiation method was fabricated for ethanol sensing. A higher sensing efficiency for ethanol for the ECL biosensor prepared by PAAc-g-MWCNT was measured compared to that of the ECL biosensor prepared by PMAc-g-MWCNT, and purified MWCNT. Experimental parameters affecting ethanol detection were also examined in terms of pH and the content of PAAc-g-MWCNT in Nafion. Little interference of other compounds was observed for the assay of ethanol. Results suggest this ECL biosensor could be applied for ethanol detection in real samples

Editorial: Nanotechnological Advances in Biosensors

A biosensor is a physicochemical or hybrid physical-chemical-biological device that detects a biological molecule, organism, or process. Because of the nature of their targets, biosensors need to be faster, smaller, more sensitive, and more specific than nearly all of their physicochemical counterparts or the traditional methods that they are designed to replace. Speed is of the essence in medical diagnosis as it permits for rapid, accurate treatment and does not allow patients to be lost to follow-up. Small size and greater sensitivity mean less-invasive sampling and detection of molecules such as neurotransmitters or hormones at biologically-relevant levels. Greater specificity allows assays to be performed in complex fluids such as blood or urine without false negative or false positive results. [...

Tyrosinase-Immobilized Biosensor Based on the Functionalized Hydroxyl Group-MWNT and Detection of Phenolic Compounds in Red Wines

The tyrosinase-immobilized biosensor was developed with the hydroxyl group-functionalized multiwall carbon nanotube (MWNT) for phenol detection. The hydroxyl group-modified MWNT was modified to include poly(GVPB)-g-MWNT, or poly(HEMA), by a radiation-induced graft polymerization of glucosyl 4-vinylphenylboronate (GVPB) or 2-hydroxyethyl methacrylate (HEMA) on the surface of MWNT. The response of biosensor was in the range of 0.6–7.0 mM for concentration and in the range of 0.05–0.35 mM for phenol in a phosphate buffer solution, respectively. Various parameters influencing biosensor performance have been optimized: for pH, temperature, and the response to various phenolic compounds. The biosensor was then tested on phenolic compounds contained in three different commercial red wines

Fabrication of Nonenzymatic Glucose Sensors Based on Multiwalled Carbon Nanotubes with Bimetallic Pt-M (M = Ru and Sn) Catalysts by Radiolytic Deposition

Nonenzymatic glucose sensors employing multiwalled carbon nanotubes (MWNTs) with highly dispersed Pt-M (M = Ru and Sn) nanoparticles (Pt-M@PVP-MWNTs) were fabricated by radiolytic deposition. The Pt-M nanoparticles on the MWNTs were characterized by transmittance electron microscopy, elemental analysis, and X-ray diffraction. They were found to be well dispersed and to exhibit alloy properties on the MWNT support. Electrochemical testing showed that these nonenzymatic sensors had larger currents (mA) than that of a bare glassy carbon (GC) electrode and one modified with MWNTs. The sensitivity (A mM−1), linear range (mM), and detection limit (mM) (S/N = 3) of the glucose sensor with the Pt-Ru catalyst in NaOH electrolyte were determined as 18.0, 1.0–2.5, 0.7, respectively. The corresponding data of the sensor with Pt-Sn catalyst were 889.0, 1.00–3.00, and 0.3, respectively. In addition, these non-enzymatic sensors can effectively avoid interference arising from the oxidation of the common interfering species ascorbic acid and uric acid in NaOH electrolyte. The experimental results show that such sensors can be applied in the detection of glucose in commercial red wine samples

Submicron patterns-on-a-chip: Fabrication of a microfluidic device incorporating 3D printed surface ornaments

Manufacturing high throughput in vitro models resembling the tissue microenvironment is highly demanded for studying bone regeneration. Tissues such as bone have complex multiscale architectures insid

Developing Electrochemical Biosensors for Point-of-care Diagnostics of Cardiovascular Biomarkers

Troponin is known as a type of reliable biomarker for the detection of cardiac disorders. Cardiac troponin I (cTnI), as a subunit of troponin, is highly sensitive to cardiac injury; therefore, the cTnI level is used as an index to diagnose myocardial damage, particularly acute myocardial infarction. It can be also used in cardiospecific diagnosis, risk stratification therapeutic treatment and post risk management. In this research, an amperometric immunosensor was developed based on planar electrode and sandwich ELISA format. The electrical response corresponding to biological information was obtained via four main procedures, including electrode modification, immunoreaction, signal amplifications and amperometric detection. Enzyme labels such as horseradish peroxide (HRP) and alkaline phosphatase (ALP) were used for signals amplification. Since alkaline phosphatase works better in low background current levels and has great reproducibility, it was used for nanomaterials, chitosan, gold nanoparticle, carbon nanotube as electrode modification investigation. The anti-cTnI antibody is detectable by electrochemical technology. Necessary conditions and interferences of the experiment were examined. Detection range was from 0.001 ng ml-1 to 300 ng ml-1 on PDDA-MWCNT sensor, and from 0.02 ng ml-1 to 200 ng ml-1 on chitosan-AuNPs sensor. The detection range was investigated using cyclic voltammetry. The signal behavior recorded was linear to cTnI concentration. This behavior makes the developed biosensor be able to widely use in clinical practice. Likewise, two liquid substrates were catalyzed by hydroquinone and 3, 3’, 5, 5’-teteramethylbenzidine respectively. Hydrogen peroxide (H2O2) is a product of glucose oxidizes catalyzing the oxidation of β-D-glucose by oxygen. It is also used as an oxidizing agent in catalyzing HRP. Hence, an HRP-based immunosensor is important in integrating an immunosensor and an enzyme sensor for the purpose of achieving multianalyte detection compacted on one chip. The cTnI immunosensor developed here is rapid, easy-to-use, cost-efficient and robust

Development of an Electrogenerated Chemiluminescence Biosensor using Carboxylic acid-functionalized MWCNT and Au Nanoparticles

A COOH-F-MWCNT-Nafion-Ru(bpy)32+-Au-ADH electrogenerated chemi-luminescence (ECL)electrode using COOH-functionalized MWCNT (COOH-F-MWCNT) and Au nanoparticles synthesized by the radiation method was fabricated for ethanol sensing. A higher sensing efficiency for ethanol for the ECL biosensor prepared by PAAc-g-MWCNT was measured compared to that of the ECL biosensor prepared by PMAc-g-MWCNT, and purified MWCNT. Experimental parameters affecting ethanol detection were also examined in terms of pH and the content of PAAc-g-MWCNT in Nafion. Little interference of other compounds was observed for the assay of ethanol. Results suggest this ECL biosensor could be applied for ethanol detection in real samples