Gold Nanoparticle-Based Microfluidic Chips for Capture and Detection of Circulating Tumor Cells.

Liquid biopsy has progressed to its current use to diagnose and monitor cancer. Despite the recent advances in investigating cancer detection and diagnosis strategies, there is still a room for improvements in capturing CTCs. We developed an efficient CTC detection system by integrating gold nanoparticles with a microfluidic platform, which can achieve CTC capture within 120 min.

Recent Advances in Functional Nanomaterials for Diagnostic and Sensing Using Self-Assembled Monolayers.

Functional nanomaterials have attracted attention by producing different structures in any field. These materials have several potential applications, including medicine, electronics, and energy, which provide many unique properties. These nanostructures can be synthesized using various methods, including self-assembly, which can be used for the same applications.

Detection of Prostate Cancer Biomarker PCA3 by Using Aptasensors.

Background: Prostate cancer cells have very high PCA3 messenger RNA levels, which turns them into one of the new biomarkers for prostate cancer prognosis and diagnosis.

Objective: Our goal here is to develop a new aptasensor to detect PCA3 release by the cancer cell.

Methods: DNA hairpin containing PCA3 aptamer was thiolated, conjugated to methylene blue (MB) redox probe, and immobilized on gold electrode through self-assembly to detect label-free cancer cells.

A global pollutant (PVC-polyvinyl chloride) applied as heavy metal binder from aqueous samples: green principles from synthesis to application.

We have developed a clean route for the modification of polyvinylchloride surface (PVC) with 4-amino-5-hydrazino-1,2,4-triazole-3-thiol molecule. The modification reaction was investigated through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis. According to our findings, S-H groups are responsible to the molecule attachment and nitrogen atoms are directly involved in metal ion coordination.

A Study of the Effects of pH and Surfactant Addition on Gold Nanoparticle Aggregation.

Gold nanoparticles (AuNPs) can provide a simple, easy-to-use, inexpensive, at hand point-of-care (POC) fast to diagnose; however, AuNPs have the predisposition to form aggregations. Since the nanoparticles stability is an important issue, this article is aiming to study the long-term stability associated with the development of an immunosensor for clinical diagnosis. Here, we assessed two previous methods commonly described in the literature to prevent the formation of aggregate by studying pH and Tween® 20 (polysorbates) addition as surfactant.

Enzyme Immobilization on Maghemite Nanoparticles with Improved Catalytic Activity: An Electrochemical Study for Xanthine.

Generally, enzyme immobilization on nanoparticles leads to nano-conjugates presenting partially preserved, or even absent, biological properties. Notwithstanding, recent research demonstrated that the coupling to nanomaterials can improve the activity of immobilized enzymes. Herein, xanthine oxidase (XO) was immobilized by self-assembly on peculiar naked iron oxide nanoparticles (surface active maghemite nanoparticles, SAMNs).

A Methodology for Porcine Circovirus 2 (PCV-2) Quantification Based on Gold Nanoparticles.

The aim of the current study is to introduce a methodology aimed at producing a biosensor that uses gold nanoparticles (AuNPs) to detect porcine circovirus 2 (PCV-2). This biosensor was based on AuNPs, which were modified with self-assembled monolayers (SAMs) and antibodies. The AuNPs' surface and virus modification process applied to enable antibody binding was accompanied by localized surface plasmon resonance (LSPR), surface plasmon resonance (SPR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX).

Anti-EGFR-Coated Gold Nanoparticles In Vitro Carry 5-Fluorouracil to Colorectal Cancer Cells.

The aim of the current study is to present a strategy to improve the efficiency of 5-fluorouracil (5-FU), which is widely used as antineoplastic agent against solid tumors-based on the use of gold nanocarriers to overcome the resistance of colorectal cancer cells. 5-FU was loaded on gold nanoparticles (AuNP) coated with anti-EGFR antibodies in order to target them towards colorectal cancer cells that overexpress epidermal growth factor receptors (EGFR). Physicochemical characterization has shown that AuNP size was approximately 20 nm and that AuNP functionalization led to spherical nanoparticles.

Electrocatalytic nanostructured ferric tannate as platform for enzyme conjugation: Electrochemical determination of phenolic compounds.

A shell of nanostructured ferric tannates was spontaneously developed on the surface of naked maghemite nanoparticles (SAMNs, the core) by a simple wet reaction with tannic acid (TA). The as obtained core-shell nanomaterial (SAMN@TA) displays specific electrocatalytic and surface properties, which significantly differ from parent maghemite. Thanks to the known proclivity of TA to interact with proteins, SAMN@TA was proposed as a support for the direct immobilization of an enzyme.

A new immunoassay of hybrid nanomater conjugated to aptamers for the detection of dengue virus.

A new immunosensor using hybrid nanomaterials for the detection of dengue virus was demonstrated in this work. This immunosensor composed of nanoparticles of γ-FeO(SAMN) modified with MPA- SAMN@MPA was characterized by FTIR spectroscopy, transmission electron microscopy,quartz crystal microbalance, UV-vis and LSPR technique. The binding of SAMN@MPA with AuNPs conjugated with aptamers(SAMN@MPA@AuNPs@aptamer) provides specific chemical bonds to four dengue serotypes.

An easy way to detect dengue virus using nanoparticle-antibody conjugates.

The aim of the present research is to propose a new method based on localized surface plasmon resonance (LSPR) for fast dengue virus detection. A pool with four dengue serotypes (DENV-1, -2, -3, -4) was detected through antigen-antibody binding using gold nanoparticles (AuNPs) as signaling antibody carriers. Such result was confirmed through surface plasmon resonance (SPR), transmission electron microcopy (TEM), and dynamic light scattering (DLS) techniques.

Electrochemical aptamer-based biosensor developed to monitor PSA and VEGF released by prostate cancer cells.

Early prostate cancer (PCa) diagnostic is crucial to enhance patient survival rates; besides, non-invasive platforms have been developed worldwide in order to precisely detect PCa biomarkers. Therefore, the aim of the present study is to develop a new aptamer-based biosensor through the self-assembling of thiolated aptamers for PSA and VEGF on the top of gold electrodes. This biosensor was tested in three prostate cell lines (RWPE-1, LNCaP and PC3).

Development of a rapid and sensitive immunosensor for the detection of bacteria.

The presence of Gram-positive bacteria in foodstuffs is a chronic worldwide problem. Here, we present a cheap and simple colorimetric method for the detection of Lactobacillus species (spp.) and Staphylococcus aureus (S.

Glucose biosensor based on multisegment nanowires exhibiting reversible magnetic control.

We describe the amperometric detection of glucose using oriented nanowires with magnetic switching of the bioelectrochemical process. The fabrication process of the nanowires was prepared through controlled nucleation and growth during a stepwise electrochemical deposition, and it was characterized using scanning electron microscopy. Cyclic voltammetry and amperometry were used to study the magnetoswitchable property; this control was accomplished by changing the surface orientation of nanowires.

Plasmonic nanobiosensor with chain reaction amplification mechanism.

Herein we demonstrate a plasmonic nanobiosensor that explores chain reaction amplification mechanisms to transduce chemical signals released in biocatalytic reactions, turning optical signals into a visual spectral range. The sensor has a very simple design: gold nanoparticles resting in the surface of a grafted P2VP film. Changes in the gold nanoparticles' position causes changes in the plasmon coupling mode.

Spectrofluorimetric determination of coumarin in commercial tablets.

A simple, rapid and effective analytical method based on fluorescence spectroscopy for the determination of coumarin in pharmaceutical formulations without pre-treatment or pre-concentration step was development. Coumarin had maximum excitation and emission at 310 nm and 390 nm, respectively. Optimum conditions for the detection of coumarin were investigated.

Immobilizing enzymes onto electrode arrays by hydrogel photolithography to fabricate multi-analyte electrochemical biosensors.

This paper describes a biomaterial microfabrication approach for interfacing functional biomolecules (enzymes) with electrode arrays. Poly (ethylene glycol) (PEG) hydrogel photopatterning was employed to integrate gold electrode arrays with the enzymes glucose oxidase (GOX) and lactate oxidase (LOX). In this process, PEG diacrylate (DA)-based prepolymer containing enzyme molecules as well as redox species (vinylferrocene) was spin-coated, registered, and UV cross-linked on top of an array of gold electrodes.

Enhanced stability of enzyme organophosphate hydrolase interfaced on the carbon nanotubes.

In this paper we demonstrate that SWNTs and a covalent immobilization strategy enable very sensitive sensors with excellent long term stability. Organophosphorus hydrolase (OPH) functionalized single and multi-walled carbon nanotube (CNT) conjugates were exploited for direct amperometric detection of paraoxon, a model organophosphate. The catalytic hydrolysis of paraoxon produces equimoles of p-nitrophenol; oxidation was monitored amperometrically in real time under flow-injection (FIA) mode.

Enzymatic nanolithography of polyaniline nanopatterns by using peroxidase-modified atomic force microscopy tips.

A new enzyme nanolithography strategy for creating conducting polymer nanostructures through the modification of AFM tips with peroxidase is described. Scanning of the modified tip in the presence of aniline and hydrogen peroxide is used for biocatalytic patterning of different polyaniline nanostructures (see figure).

Determination of Parathion and Carbaryl Pesticides in Water and Food Samples Using a Self Assembled Monolayer /Acetylcholinesterase Electrochemical Biosensor.

An acetylcholinesterase (AchE) based amperometric biosensor was developed by immobilisation of the enzyme onto a self assembled modified gold electrode. Cyclic voltammetric experiments performed with the SAM-AchE biosensor in phosphate buffer solutions (pH = 7.2) containing acetylthiocholine confirmed the formation of thiocholine and its electrochemical oxidation at E = 0.