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Graphene-Based Materials for Biomedical and Environmental Applications

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Materials".

Deadline for manuscript submissions: closed (20 August 2022) | Viewed by 12629

Special Issue Editors


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Guest Editor
National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street, No. 67-103, RO-400293 Cluj-Napoca, Romania
Interests: graphene synthesis by electrochemical methods; graphene-modified electrodes; electrochemical detection of biomolecules (e.g., adenine; guanine; dopamine); pharmaceutical drugs and organic polutants
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Analytical Chemistry, Faculty of Pharmacy, Iuliu Hatieganu University of Medicine and Pharmacy, 4 Pasteur Street, 400349 Cluj-Napoca, Romania
Interests: electrochemical and optical sensors; graphene; nanomaterials based electrodes; bioanalysis
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Analytical Chemistry Department, Iuliu Hatieganu University of Medicine and Pharmacy in Cluj-Napoca, Cluj Napoca, Romania
Interests: analytical chemistry; electrochemistry, electrochemical (bio)sensors; graphene; composite materials for electrode functionalization; biomedical and environmental applications
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Graphene is a planar sheet of carbon atoms and has numerous advantages compared to other materials in the construction of sensors and biosensors. The large surface area and the easiness in the transfer of electrons make such material highly sensitive towards interface changes, thus contributing to the fabrication of improved sensor/biosensor devices. In addition, graphene can be easily functionalized with various biomolecules (DNA, proteins, peptides) by π–π stacking and hydrophobic interactions or with metal/metal oxide nanoparticles, forming composites desirable in biomedical and environmental applications.

This Special Issue is addressed to all types of sensors/biosensors using graphene and functionalized graphene, designed for biomedical and environmental analysis.

Dr. Stela-Maria Pruneanu
Prof. Dr. Cecilia Cristea
Dr. Mihaela Tertis
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • graphene
  • nitrogen-doped graphene
  • sulfur-doped graphene
  • graphene–metal/metal oxide nanoparticle composites
  • sensors
  • biosensors
  • biomedical applications
  • environmental applications

Published Papers (4 papers)

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13 pages, 3758 KiB  
Article
Electrochemical L-Tyrosine Sensor Based on a Glassy Carbon Electrode Modified with Exfoliated Graphene
by Codruţa Varodi, Florina Pogăcean, Maria Coroş, Alexandra Ciorîță and Stela Pruneanu
Sensors 2022, 22(10), 3606; https://doi.org/10.3390/s22103606 - 10 May 2022
Cited by 3 | Viewed by 1748
Abstract
In this study, a graphene sample (EGr) was synthesized by electrochemical exfoliation of graphite rods in electrolyte solution containing 0.1 M ammonia and 0.1 M ammonium thiocyanate. The morphology of the powder deposited onto a solid substrate was investigated by the scanning electron [...] Read more.
In this study, a graphene sample (EGr) was synthesized by electrochemical exfoliation of graphite rods in electrolyte solution containing 0.1 M ammonia and 0.1 M ammonium thiocyanate. The morphology of the powder deposited onto a solid substrate was investigated by the scanning electron microscopy (SEM) technique. The SEM micrographs evidenced large and smooth areas corresponding to the basal plane of graphene as well as white lines (edges) where graphene layers fold-up. The high porosity of the material brings a major advantage, such as the increase of the active area of the modified electrode (EGr/GC) in comparison with that of bare glassy carbon (GC). The graphene modified electrode was successfully tested for L-tyrosine detection and the results were compared with those of bare GC. For EGr/GC, the oxidation peak of L-tyrosine had high intensity (1.69 × 10−5 A) and appeared at lower potential (+0.64 V) comparing with that of bare GC (+0.84 V). In addition, the graphene-modified electrode had a considerably larger sensitivity (0.0124 A/M) and lower detection limit (1.81 × 10−6 M), proving the advantages of employing graphene in electrochemical sensing. Full article
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14 pages, 4239 KiB  
Article
Hydrothermal Synthesis of Nitrogen, Boron Co-Doped Graphene with Enhanced Electro-Catalytic Activity for Cymoxanil Detection
by Codruța Varodi, Florina Pogăcean, Maria Coros, Lidia Magerusan, Raluca-Ioana Stefan-van Staden and Stela Pruneanu
Sensors 2021, 21(19), 6630; https://doi.org/10.3390/s21196630 - 05 Oct 2021
Cited by 7 | Viewed by 2129
Abstract
A sample of nitrogen and boron co-doped graphene (NB-Gr) was obtained by the hydrothermal method using urea and boric acid as doping sources. According to XRD analysis, the NB-Gr sample was formed by five-layer graphene. In addition, the XPS analysis confirmed the nitrogen [...] Read more.
A sample of nitrogen and boron co-doped graphene (NB-Gr) was obtained by the hydrothermal method using urea and boric acid as doping sources. According to XRD analysis, the NB-Gr sample was formed by five-layer graphene. In addition, the XPS analysis confirmed the nitrogen and boron co-doping of the graphene sample. After synthesis, the investigation of the electro-catalytic properties of the bare (GC) and graphene-modified electrode (NB-Gr/GC) towards cymoxanil detection (CYM) was performed. Significant differences between the two electrodes were noticed. In the first case (GC) the peak current modulus was small (1.12 × 10−5 A) and appeared in the region of negative potentials (−0.9 V). In contrast, when NB-Gr was present on top of the GC electrode it promoted the transfer of electrons, leading to a large peak current increase (1.65 × 10−5 A) and a positive shift of the peak potential (−0.75 V). The NB-Gr/GC electrode was also tested for its ability to detect cymoxanil from a commercial fungicide (CURZATE MANOX) by the standard addition method, giving a recovery of 99%. Full article
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18 pages, 5707 KiB  
Article
Nitrogen-Doped Graphene: The Influence of Doping Level on the Charge-Transfer Resistance and Apparent Heterogeneous Electron Transfer Rate
by Maria Coros, Codruta Varodi, Florina Pogacean, Emese Gal and Stela M. Pruneanu
Sensors 2020, 20(7), 1815; https://doi.org/10.3390/s20071815 - 25 Mar 2020
Cited by 41 | Viewed by 5293
Abstract
Three nitrogen-doped graphene samples were synthesized by the hydrothermal method using urea as doping/reducing agent for graphene oxide (GO), previously dispersed in water. The mixture was poured into an autoclave and placed in the oven at 160 °C for 3, 8 and 12 [...] Read more.
Three nitrogen-doped graphene samples were synthesized by the hydrothermal method using urea as doping/reducing agent for graphene oxide (GO), previously dispersed in water. The mixture was poured into an autoclave and placed in the oven at 160 °C for 3, 8 and 12 h. The samples were correspondingly denoted NGr-1, NGr-2 and NGr-3. The effect of the reaction time on the morphology, structure and electrochemical properties of the resulting materials was thoroughly investigated using scanning electron microscopy (SEM) Raman spectroscopy, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), elemental analysis, Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For NGr-1 and NGr-2, the nitrogen concentration obtained from elemental analysis was around 6.36 wt%. In the case of NGr-3, a slightly higher concentration of 6.85 wt% was obtained. The electrochemical studies performed with NGr modified electrodes proved that the charge-transfer resistance (Rct) and the apparent heterogeneous electron transfer rate constant (Kapp) depend not only on the nitrogen doping level but also on the type of nitrogen atoms found at the surface (pyrrolic-N, pyridinic-N or graphitic-N). In our case, the NGr-1 sample which has the lowest doping level and the highest concentration of pyrrolic-N among all nitrogen-doped samples exhibits the best electrochemical parameters: a very small Rct (38.3 Ω), a large Kapp (13.9 × 10−2 cm/s) and the best electrochemical response towards 8-hydroxy-2′-deoxyguanosine detection (8-OHdG). Full article
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11 pages, 2718 KiB  
Letter
Wavelength Dependent Graphene Oxide-Based Optical Microfiber Sensor for Ammonia Gas
by Saad Hayatu Girei, Mohammed Majeed Alkhabet, Yasmin Mustapha Kamil, Hong Ngee Lim, Mohd Adzir Mahdi and Mohd Hanif Yaacob
Sensors 2021, 21(2), 556; https://doi.org/10.3390/s21020556 - 14 Jan 2021
Cited by 15 | Viewed by 2556
Abstract
Ammonia detection in ambient air is critical, given its implication on the environment and human health. In this work, an optical fiber tapered to a 20 µm diameter and coated with graphene oxide was developed for absorbance response monitoring of ammonia at visible [...] Read more.
Ammonia detection in ambient air is critical, given its implication on the environment and human health. In this work, an optical fiber tapered to a 20 µm diameter and coated with graphene oxide was developed for absorbance response monitoring of ammonia at visible (500–700 nm) and near-infrared wavelength regions (700–900 nm). The morphology, surface characteristics, and chemical composition of the graphene oxide samples were confirmed by a field emission scanning electron microscope, an atomic force microscope, X-ray diffraction, and an energy dispersion X-ray. The sensing performance of the graphene oxide-coated optical microfiber sensor towards ammonia at room temperature revealed better absorbance response at the near-infrared wavelength region compared to the visible region. The sensitivity, response and recovery times at the near-infrared wavelength region were 61.78 AU/%, 385 s, and 288 s, respectively. The sensitivity, response and recovery times at the visible wavelength region were 26.99 AU/%, 497 s, and 192 s, respectively. The selectivity of the sensor towards ammonia was affirmed with no response towards other gases. Full article
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