Carbon nanodots based biosensors for gene mutation detection

This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo periodAn electrochemical DNA biosensor based on a carbon nanodots (CDs) modified screen-printed gold electrode as a transducer is reported in this work. CDs were synthesized by thermal carbonization of ethyleneglycol bis-(2-aminoethylether)-N,N,N’,N’-tetraacetic acid (EGTA) and characterized by different techniques (DLS, TEM, FTIR, Raman). The electrode surface modification was accomplished by drop-casting a suspension of CDs. SEM analysis and cyclic voltammetry were used to characterize the resulting modified electrode. Synthetic 25-mer or 100-mer DNA capture probes, capable to hybridize with a specific sequence of the pathogen Helicobacter pylori or the cystic fibrosis transmembrane regulator (CFTR) gene were attached to the CDs-gold surface. A 25-bases synthetic fully complementary sequence or a single nucleotide polymorphism to the DNA capture probe and a 373-bases PCR amplicon of exon 11 of CFTR containing a sequence complementary to the capture probe, were employed as target. The hybridization event was electrochemically monitored by using safranine as redox indicator, which selectively binds to double stranded DNA (dsDNA). A detection limit of 0.16 nM was obtained for the 25-mer synthetic target DNA. The biosensor shows a very high reproducibility and selectivity, allowing to detect a single nucleotide polymorphism. It has been applied to the detection of F508del mutation in the CFTR geneThis work has been supported by the Comunidad Autónoma de Madrid NANOAVANSENS (project No. S2013/MIT-3029) and Spanish Ministerio de Economía, Industria y Competitividad through projects Nos. CTQ2015-71955-REDT (ELECTROBIONET) and CTQ2014-53334-C2-1-R. E. L. thanks the Fulbright scholarship-Salvador de Madariaga program from Spanish Ministerio de Economía, Industria y Competitividad. I. B. gratefully acknowledges the FPI-2012 Grant from Spanish Ministerio de Economía y Competitividad. R.W. gratefully acknowledges support by the European Union structural funds and the Comunidad de Madrid MAD2D-CM Program (S2013/MIT-3007), as well as by the Spanish Ministerio de Economía, Industria y Competitividad through project No. MAT2015-71879-

Eco-Friendly Fluorescent Carbon Nanodots: Characteristics and Potential Applications

Carbon nanodots are zero-dimensional tiny particles of carbon with outstanding characteristics and potential applications. Carbon nanodots are fluorescent materials and possess unique characteristics such as biocompatibility, photostability, low toxicity, sustainable, and eco-friendly. Fluorescent carbon nanodots are emerging nanomaterials that show promising potential in bioimaging, optical sensing, information encryption and storage, photocatalysis, lasers, drug delivery, energy conversion, and photovoltaic applications. Carbon nanodots can be synthesized at very low cost through various sustainable approaches that employ inexpensive renewable resources as starting materials. Carbon nanodots are fascinating carbon-based materials that have received mass attention from past few years for their substantial applications in diverse fields. Carbon nanodots have a huge impact on both health and environmental applications because of their potential to serve as nontoxic replacements to traditional heavy metal-based quantum dots. Herein we highlight the intriguing characteristics and potential applications of fluorescent carbon nanodots in various fields and their perspective in future

Development of nanostructured material based electrochemical sensors for food safety and quality control

The issue of foodborne related illnesses due to additives and contaminants poses a significant challenge to food processing industries. Electrochemical-based strategies offer simple and robust analytical tools, which are ideal for food safety and the quality assessment process, in contrast to conventional instrumentation methods. The development of nanomaterials based electrochemical sensors has garnered significant attention due to their capacity for accurate analytical quantification, which has strong potential toward the replacement of conventional techniques by offering advantages such as high sensitivity and selectivity, real-time monitoring, and ease of use. During my Ph.D. study, four distinct types of nanostructured materials were used to develop electrochemical sensors for the detection of food preservatives in food and beverage products. The consumption of excessive amounts of nitrite (NO2-) can be detrimental to the human body. In light of this, we developed an electrochemical sensor based on cobalt oxide nanosheets and gold nanoparticles (Co3O4/Au) for NO2- sensing. The nanomaterial was synthesized through the electrodeposition of gold (Au) on Co3O4 nanosheets. The Co3O4/Au/GCE was capable of electrooxidizing nitrite with a higher anodic peak current, and the sensor exhibited excellent linearity with a limit of detection (LOD) value of 0.11 μM. A nanoporous gold microelectrode was synthesized for the determination of contaminants (hydrazine, N2H4) and preservatives (sulfite (SO32-), nitrite (NO2-)). The fabricated microelectrode was characterized via scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The nanoporous gold microelectrode exhibited excellent electrochemical performance for the simultaneous electrochemical oxidation of N2H4, SO32-, and NO2-. In addition, the nanoporous gold microelectrode possessed high selectivity and stability. The performance of ii the electrochemical sensor was further validated using actual samples such as water, wine, apple cider beer, and beef with good recovery rates, thereby confirming its potential for food safety and quality control applications. A novel electrochemical sensor was developed using fluorine-doped graphene oxide (F-GO) for the detection of caffeic acid (CA). The fabricated nanomaterial was systematically characterized using SEM and X-ray photoelectron spectroscopy (XPS). The electrochemical investigation of F-GO/GCE for CA oxidation revealed that it demonstrated high electrocatalytic activity compared with other electrodes (e.g., bare GCE and GO/GCE). The analytical quantitation of CA recorded with the F-GO/GCE produced a stable oxidation signal over the selected CA concentration range (0.5 μM to 100.0 μM, R2 = 0.9960) with a LOD value of 0.018 μM. The fabricated sensor successfully exhibited the capacity to directly detect CA in assorted wine samples without pretreatment. To further explore the applications of the F-GO, a nanocomposite material synthesized with Au and F-GO was employed for the development of an Au/F-rGO/GCE sensor for the detection of vanillin. The electrochemical performance and the analytical capabilities of this novel electrochemical sensor were investigated using electrochemical techniques such as CV and DPV. The excellent sensitivity, selectivity, augmented electrocatalytic activity, and reproducibility of these developed electrochemical sensors can be attributed to the high conductivity of the nanostructured materials. The dimensions and morphologies of the developed nanomaterials played a critical role in enhancing the electrochemical performance of these sensors

Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination

Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O2. The specific amino-carboxyl reaction provides strong and stable immobilization of GOx on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors

Carbon-Based Material for Environmental Protection and Remediation

Carbon-Based Material for Environmental Protection and Remediation presents an overview of carbon-based technologies and processes, and examines their usefulness and efficiency for environmental preservation and remediation. Chapters cover topics ranging from pollutants removal to new processes in materials science. Written for interested readers with strong scientific and technological backgrounds, this book will appeal to scientific advisors at private companies, academics, and graduate students

Carbon-Based Material for Environmental Protection and Remediation

Carbon-Based Material for Environmental Protection and Remediation presents an overview of carbon-based technologies and processes, and examines their usefulness and efficiency for environmental preservation and remediation. Chapters cover topics ranging from pollutants removal to new processes in materials science. Written for interested readers with strong scientific and technological backgrounds, this book will appeal to scientific advisors at private companies, academics, and graduate students