17 results on '"Amandeep Singh Pannu"'
Search Results
2. Impact of hair-derived carbon substitution on structural and superconducting properties of MgB2
- Author
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Mahboobeh Shahbazi, Amandeep Singh Pannu, Jose Alarco, Prashant Sonar, and Ian Mackinnon
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Physics ,QC1-999 - Abstract
This study presents a comprehensive analysis of the effects resulting from the substitution of biowaste-derived carbon-dot (CD) from human hair on structural and superconducting properties of MgB2. Syntheses of polycrystalline samples were accomplished through a standard solid-state reaction route. X-ray powder diffraction results confirm the formation of MgB2 as a primary phase in all samples and show the successful substitution of carbon for boron in MgB2. The critical current density, determined at 20 K and 4.5 T, for carbon-substituted MgB2 synthesized at 850 °C was enhanced by more than four times compared with unsubstituted MgB2. The observed improvement is due to the formation of efficient pinning centers resulting from the incorporation of carbon substituting for boron in MgB2. Furthermore, x-ray photoelectron spectroscopy (XPS) confirmed the presence of carbon bonding to boron in MgB2 synthesized with biowaste-derived CDs, indicating successful incorporation into the structure. Ultraviolet photoelectron spectroscopy (UPS) results show that the carbon-substituted MgB2 can lead to changes in the electronic band structure and values of work function. These changes significantly impact the properties of MgB2 materials, including superconducting transition temperature, upper critical field, and critical current density. The XPS and UPS experimental results are in good agreement with density functional theory calculations for MgB2 with and without carbon substitution.
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- 2023
- Full Text
- View/download PDF
3. Surface Treatment of Inorganic CsPbI3 Nanocrystals with Guanidinium Iodide for Efficient Perovskite Light-Emitting Diodes with High Brightness
- Author
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Minh Tam Hoang, Amandeep Singh Pannu, Yang Yang, Sepideh Madani, Paul Shaw, Prashant Sonar, Tuquabo Tesfamichael, and Hongxia Wang
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CsPbI3 perovskites ,Nanocrystals ,Light-emitting diodes ,Photoluminescence ,Surface passivation ,Guanidinium iodide ,Technology - Abstract
Abstract The remarkable evolution of metal halide perovskites in the past decade makes them promise for next-generation optoelectronic material. In particular, nanocrystals (NCs) of inorganic perovskites have demonstrated excellent performance for light-emitting and display applications. However, the presence of surface defects on the NCs negatively impacts their performance in devices. Herein, we report a compatible facial post-treatment of CsPbI3 nanocrystals using guanidinium iodide (GuI). It is found that the GuI treatment effectively passivated the halide vacancy defects on the surface of the NCs while offering effective surface protection and exciton confinement thanks to the beneficial contribution of iodide and guanidinium cation. As a consequence, the film of treated CsPbI3 nanocrystals exhibited significantly enhanced luminescence and charge transport properties, leading to high-performance light-emitting diode with maximum external quantum efficiency of 13.8% with high brightness (peak luminance of 7039 cd m−2 and a peak current density of 10.8 cd A−1). The EQE is over threefold higher than performance of untreated device (EQE: 3.8%). The operational half-lifetime of the treated devices also was significantly improved with T50 of 20 min (at current density of 25 mA cm−2), outperforming the untreated devices (T50 ~ 6 min).
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- 2022
- Full Text
- View/download PDF
4. Versatile aza‐BODIPY‐based low‐bandgap conjugated small molecule for light harvesting and near‐infrared photodetection
- Author
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Gurudutt Bhat, Marcin Kielar, Haixia Rao, Mahnaz D. Gholami, Isabel Mathers, Astrid C. R. Larin, Thomas Flanagan, Enkhtur Erdenebileg, Annalisa Bruno, Amandeep Singh Pannu, Kathryn E. Fairfull‐Smith, Emad L. Izake, Pankaj Sah, Yeng Ming Lam, Ajay K. Pandey, and Prashant Sonar
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BODIPY ,multifunctionality ,organic photodetector ,perovskite solar cell ,TPA ,TPA‐azaBODIPY‐TPA ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Information technology ,T58.5-58.64 - Abstract
Abstract The versatile nature of organic conjugated materials renders their flawless integration into a diverse family of optoelectronic devices with light‐harvesting, photodetection, or light‐emitting capabilities. Classes of materials that offer the possibilities of two or more distinct optoelectronic functions are particularly attractive as they enable smart applications while providing the benefits of the ease of fabrication using low‐cost processes. Here, we develop a novel, multi‐purpose conjugated small molecule by combining boron‐azadipyrromethene (aza‐BODIPY) as electron acceptor with triphenylamine (TPA) as end‐capping donor units. The implemented donor–acceptor–donor (D–A–D) configuration, in the form of TPA‐azaBODIPY‐TPA, preserves ideal charge transfer characteristics with appropriate excitation energy levels, with the additional ability to be used as either a charge transporting interlayer or light‐sensing semiconducting layer in optoelectronic devices. To demonstrate its versatility, we first show that TPA‐azaBODIPY‐TPA can act as an excellent hole transport layer in methylammonium lead triiodide (MAPbI3)‐based perovskite solar cells with measured power conversion efficiencies exceeding 17%, outperforming control solar cells with PEDOT:PSS by nearly 60%. Furthermore, the optical bandgap of 1.49 eV is shown to provide significant photodetection in the wavelength range of up to 800 nm where TPA‐azaBODIPY‐TPA functions as donor in near‐infrared organic photodetectors (OPDs) composed of fullerene derivatives. Overall, the established versatility of TPA‐azaBODIPY‐TPA, combined with its robust thermal stability as well as excellent solubility and processability, provides a new guide for developing highly efficient multi‐purpose electronic materials for the next‐generation of smart optoelectronic devices.
- Published
- 2022
- Full Text
- View/download PDF
5. Electrochemical Detection of Global DNA Methylation Using Biologically Assembled Polymer Beads
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Narshone Soda, Zennia Jean Gonzaga, Amandeep Singh Pannu, Navid Kashaninejad, Richard Kline, Carlos Salomon, Nam-Trung Nguyen, Prashant Sonar, Bernd H. A. Rehm, and Muhammad J. A. Shiddiky
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electrochemical detection ,DNA methylation ,ovarian cancer ,polyhydroxybuytrate nanobeads ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
DNA methylation is a cell-type-specific epigenetic marker that is essential for transcriptional regulation, silencing of repetitive DNA and genomic imprinting. It is also responsible for the pathogenesis of many diseases, including cancers. Herein, we present a simple approach for quantifying global DNA methylation in ovarian cancer patient plasma samples based on a new class of biopolymer nanobeads. Our approach utilises the immune capture of target DNA and electrochemical quantification of global DNA methylation level within the targets in a three-step strategy that involves (i) initial preparation of target single-stranded DNA (ss-DNA) from the plasma of the patients’ samples, (ii) direct adsorption of polymer nanobeads on the surface of a bare screen-printed gold electrode (SPE-Au) followed by the immobilisation of 5-methylcytosine (5mC)-horseradish peroxidase (HRP) antibody, and (iii) immune capture of target ss-DNA onto the electrode-bound PHB/5mC-HRP antibody conjugates and their subsequent qualification using the hydrogen peroxide/horseradish peroxidase/hydroquinone (H2O2/HRP/HQ) redox cycling system. In the presence of methylated DNA, the enzymatically produced (in situ) metabolites, i.e., benzoquinone (BQ), binds irreversibly to cellular DNA resulting in the unstable formation of DNA adducts and induced oxidative DNA strand breakage. These events reduce the available BQ in the system to support the redox cycling process and sequel DNA saturation on the platform, subsequently causing high Coulombic repulsion between BQ and negatively charged nucleotide strands. Thus, the increase in methylation levels on the electrode surface is inversely proportional to the current response. The method could successfully detect as low as 5% methylation level. In addition, the assay showed good reproducibility (% RSD ≤ 5%) and specificity by analysing various levels of methylation in cell lines and plasma DNA samples from patients with ovarian cancer. We envision that our bioengineered polymer nanobeads with high surface modification versatility could be a useful alternative platform for the electrochemical detection of varying molecular biomarkers.
- Published
- 2021
- Full Text
- View/download PDF
6. Hybrid 2D perovskite and red emitting carbon dot composite for improved stability and efficiency of LEDs
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Amandeep Singh Pannu, Suvankar Sen, Xiaodong (Tony) Wang, Robert Jones, Kostya (Ken) Ostrikov, and Prashant Sonar
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General Materials Science - Abstract
To improve operational stability of perovskite (PSK) LEDs, we used red-emitting hydrophobic carbon dots to impart structural stability to 2D PSK and reduce band offset, improving the operational stability of device to 8 hours from less than 2 hours.
- Published
- 2023
7. Potential Avenues for Exosomal Isolation and Detection Methods to Enhance Small-Cell Lung Cancer Analysis
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Waqar Ahmed Afridi, Simon Strachan, Surasak Kasetsirikul, Amandeep Singh Pannu, Narshone Soda, Daniel Gough, Nam-Trung Nguyen, and Muhammad J. A. Shiddiky
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Environmental Engineering ,Industrial and Manufacturing Engineering - Published
- 2023
8. Back Cover Image
- Author
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Gurudutt Bhat, Marcin Kielar, Haixia Rao, Mahnaz D. Gholami, Isabel Mathers, Astrid C. R. Larin, Thomas Flanagan, Enkhtur Erdenebileg, Annalisa Bruno, Amandeep Singh Pannu, Kathryn E. Fairfull‐Smith, Emad L. Izake, Pankaj Sah, Yeng Ming Lam, Ajay K. Pandey, and Prashant Sonar
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Materials Science (miscellaneous) ,Materials Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
9. Versatile <scp>aza‐BODIPY</scp> ‐based <scp>low‐bandgap</scp> conjugated small molecule for light harvesting and <scp>near‐infrared</scp> photodetection
- Author
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Gurudutt Bhat, Marcin Kielar, Haixia Rao, Mahnaz D. Gholami, Isabel Mathers, Astrid C. R. Larin, Thomas Flanagan, Enkhtur Erdenebileg, Annalisa Bruno, Amandeep Singh Pannu, Kathryn E. Fairfull‐Smith, Emad L. Izake, Pankaj Sah, Yeng Ming Lam, Ajay K. Pandey, Prashant Sonar, School of Materials Science and Engineering, and Energy Research Institute @ NTU (ERI@N)
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Organic Photodetector ,Materials [Engineering] ,Materials Science (miscellaneous) ,Multifunctionality ,Materials Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
The versatile nature of organic conjugated materials renders their flawless integration into a diverse family of optoelectronic devices with light-harvesting, photodetection, or light-emitting capabilities. Classes of materials that offer the possibilities of two or more distinct optoelectronic functions are particularly attractive as they enable smart applications while providing the benefits of the ease of fabrication using low-cost processes. Here, we develop a novel, multi-purpose conjugated small molecule by combining boron-azadipyrromethene (aza-BODIPY) as electron acceptor with triphenylamine (TPA) as end-capping donor units. The implemented donor–acceptor–donor (D–A–D) configuration, in the form of TPA-azaBODIPY-TPA, preserves ideal charge transfer characteristics with appropriate excitation energy levels, with the additional ability to be used as either a charge transporting interlayer or light-sensing semiconducting layer in optoelectronic devices. To demonstrate its versatility, we first show that TPA-azaBODIPY-TPA can act as an excellent hole transport layer in methylammonium lead triiodide (MAPbI3)-based perovskite solar cells with measured power conversion efficiencies exceeding 17%, outperforming control solar cells with PEDOT:PSS by nearly 60%. Furthermore, the optical bandgap of 1.49 eV is shown to provide significant photodetection in the wavelength range of up to 800 nm where TPA-azaBODIPY-TPA functions as donor in near-infrared organic photodetectors (OPDs) composed of fullerene derivatives. Overall, the established versatility of TPA-azaBODIPY-TPA, combined with its robust thermal stability as well as excellent solubility and processability, provides a new guide for developing highly efficient multi-purpose electronic materials for the next-generation of smart optoelectronic devices. Ministry of Education (MOE) National Research Foundation (NRF) Published version Lam Yeng Ming would like to thank the support of the Singapore Ministry of Education Academic Research Fund Tier 2 (Grant No. MOE2019-T2-1-085). Annalisa Bruno and Enkhtur thank the National Research Foundation for the financial support (Grant No. S18-1176-SCRP). Prashant Sonar is thankful to QUT for the financial support from the Australian Research Council (ARC) for the Future Fellowship (Grant No. FT130101337) and QUT core funding (Grant No. QUT/322120-0301/07). Ajay K. Pandey acknowledges support from Australia India Strategic Research Fund (Project AISRF53820).
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- 2022
10. Isolation and Detection of Exosomes Using Fe2O3 Nanoparticles
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Amandeep Singh Pannu, Mahboobeh Shahbazi, Aiden Jabur, Kostya Ostrikov, Prashant Sonar, Muhammad Umer, Muhammad J. A. Shiddiky, Fatema Zerin Farhana, Ayad Saeed, Hyun Jae Nam, and Shakhawat H. Firoz
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Detection limit ,education.field_of_study ,Chromatography ,Bioconjugation ,Population ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Exosome ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,General Materials Science ,Nanocarriers ,0210 nano-technology ,education ,Biosensor ,Iron oxide nanoparticles - Abstract
Magnetic nanozymes with peroxidase-mimicking activity have been widely investigated for developing molecular biosensors. Herein, we report a starch-assisted method for the synthesis of a novel class of carboxyl group-functionalized iron oxide nanoparticles (C-IONPs). Scanning electron and transmission electron microscopy analysis revealed that the nanoparticles possess a spherical shape with an average size of ∼250 nm. Peroxidase-mimicking activity of C-IONPs was investigated through catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. The results showed that nanoparticles follow typical Michaelis−Menten kinetics and exhibit excellent affinity toward TMB and H2O2 with estimated KM and VMax values of 0.0992 mM and 0.156 × 10−8 Ms−1 for TMB and 114 mM and 0.197 × 10−8 Ms−1 for H2O2, respectively. C-IONPs were used to develop a simple method for the direct isolation and quantification of disease-specific exosomes. This method utilized a two-step strategy that involved (a) initial isolation of bulk exosomes present in the sample media using tetraspanin biomarker (i.e., CD9)-functionalized C-IONPs and (b) subsequent electrochemical quantification of disease-specific exosomes within the captured bulk exosomes using tumor-specific markers (in this case, the ovarian cancer biomarker CA-125). In the first step, C-IONPs were used as “dispersible nanocarriers” to capture the bulk population of exosomes, and in the second step, they were used as nanozymes to generate an enzyme-catalyzed current indicative of the presence of tumor-specific exosomes. Chronoamperometric analysis showed that the method exhibits an excellent specificity for OVCAR3 cell-derived exosomes (linear dynamic range, 6.25 × 105 to 1.0 × 107 exosomes/mL; detection limit, 1.25 × 106 exosomes/mL) with a relative standard deviation of
- Published
- 2021
11. Electropolymerized Porous Polymer Films on Flexible Indium Tin Oxide Using Trifunctional Furan Substituted Benzene Conjugated Monomer for Biosensing
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Muhammad J. A. Shiddiky, Prashant Sonar, Jennifer MacLeod, Godwin A. Ayoko, Supreetha Paleyanda Ponnappa, Narshone Soda, Anthony P. O'Mullane, Amandeep Singh Pannu, and Muhammad Umer
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chemistry.chemical_classification ,Conductive polymer ,Materials science ,Polymers and Plastics ,010405 organic chemistry ,Process Chemistry and Technology ,Organic Chemistry ,02 engineering and technology ,Polymer ,Chronoamperometry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Conjugated microporous polymer ,Indium tin oxide ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymerization ,Chemical engineering ,Electrochromism ,0210 nano-technology - Abstract
In recent years, conducting polymers are playing a significant role in the field of display devices, transistors, solar cells, sensors, and electrochromic windows due to their outstanding optoelectronic and semiconducting properties due to their conjugated backbone. One potential application that is not as widely explored using these materials is biosensing, where advantage is taken of the porosity that can be generated by the polymerization of a three-dimensional network. There are various approaches for producing conjugated microporous polymers using trifunctional or multifunctional monomers synthesized via chemical or electrochemical methods. In this work, we have used electropolymerization to synthesize conjugated polymer films on a working electrode of flexible indium tin oxide (FITO) using a trifunctional conjugated monomer 1,3,5-tri(furan-2-yl)benzene (TFB). There are several parameters that influence the formation of a porous polymer film, and the most critical ones are substrate conductivity, roughness, method of electropolymerization, and choice of an electrolyte. These porous electropolymerized films were characterized using UV–vis spectroscopy (UV–vis), X-ray photoelectron spectroscopy (XPS), surface profilometry, four-point probe conductivity measurements, and scanning electron microscopy (SEM). The polymer films that were electropolymerized using chronoamperometry rather than repetitive potential cycling demonstrated a more suitable morphology to trap DNA/RNA analytes for biosensing applications.
- Published
- 2020
12. Surface Treatment of Inorganic CsPbI
- Author
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Minh Tam, Hoang, Amandeep Singh, Pannu, Yang, Yang, Sepideh, Madani, Paul, Shaw, Prashant, Sonar, Tuquabo, Tesfamichael, and Hongxia, Wang
- Abstract
The remarkable evolution of metal halide perovskites in the past decade makes them promise for next-generation optoelectronic material. In particular, nanocrystals (NCs) of inorganic perovskites have demonstrated excellent performance for light-emitting and display applications. However, the presence of surface defects on the NCs negatively impacts their performance in devices. Herein, we report a compatible facial post-treatment of CsPbI
- Published
- 2021
13. Electrochemical Detection of Global DNA Methylation Using Biologically Assembled Polymer Beads
- Author
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Prashant Sonar, Nam-Trung Nguyen, Richard Kline, Carlos Salomon, Navid Kashaninejad, Zennia Jean Gonzaga, Amandeep Singh Pannu, Narshone Soda, Muhammad J. A. Shiddiky, and Bernd H. A. Rehm
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0301 basic medicine ,Cancer Research ,02 engineering and technology ,Horseradish peroxidase ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Nucleotide ,Epigenetics ,RC254-282 ,chemistry.chemical_classification ,DNA methylation ,biology ,Chemistry ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Methylation ,021001 nanoscience & nanotechnology ,3. Good health ,030104 developmental biology ,ovarian cancer ,Oncology ,Biochemistry ,electrochemical detection ,polyhydroxybuytrate nanobeads ,biology.protein ,0210 nano-technology ,Genomic imprinting ,DNA ,Peroxidase - Abstract
Simple Summary Genomic profiling of cancer-derived materials in circulation has become an alternative approach for tumour genotyping. The detection of tumour origin markers such as DNA methylation in bodily fluids enables cancer screening, early-stage diagnosis and evaluation of therapy response. The development of broad platform technologies that underpin many in vitro clinical diagnostic tests has brought about a paradigm shift in cancer management and diagnosis. This study developed a multifaceted technology platform based on bioengineered polymer nanobeads for efficient capture and electrochemical detection of DNA methylation in ovarian cancer patient samples. This could be a versatile diagnostic platform for detecting numerous disease biomarkers, thus allowing several disease diagnoses. Abstract DNA methylation is a cell-type-specific epigenetic marker that is essential for transcriptional regulation, silencing of repetitive DNA and genomic imprinting. It is also responsible for the pathogenesis of many diseases, including cancers. Herein, we present a simple approach for quantifying global DNA methylation in ovarian cancer patient plasma samples based on a new class of biopolymer nanobeads. Our approach utilises the immune capture of target DNA and electrochemical quantification of global DNA methylation level within the targets in a three-step strategy that involves (i) initial preparation of target single-stranded DNA (ss-DNA) from the plasma of the patients’ samples, (ii) direct adsorption of polymer nanobeads on the surface of a bare screen-printed gold electrode (SPE-Au) followed by the immobilisation of 5-methylcytosine (5mC)-horseradish peroxidase (HRP) antibody, and (iii) immune capture of target ss-DNA onto the electrode-bound PHB/5mC-HRP antibody conjugates and their subsequent qualification using the hydrogen peroxide/horseradish peroxidase/hydroquinone (H2O2/HRP/HQ) redox cycling system. In the presence of methylated DNA, the enzymatically produced (in situ) metabolites, i.e., benzoquinone (BQ), binds irreversibly to cellular DNA resulting in the unstable formation of DNA adducts and induced oxidative DNA strand breakage. These events reduce the available BQ in the system to support the redox cycling process and sequel DNA saturation on the platform, subsequently causing high Coulombic repulsion between BQ and negatively charged nucleotide strands. Thus, the increase in methylation levels on the electrode surface is inversely proportional to the current response. The method could successfully detect as low as 5% methylation level. In addition, the assay showed good reproducibility (% RSD ≤ 5%) and specificity by analysing various levels of methylation in cell lines and plasma DNA samples from patients with ovarian cancer. We envision that our bioengineered polymer nanobeads with high surface modification versatility could be a useful alternative platform for the electrochemical detection of varying molecular biomarkers.
- Published
- 2021
14. Synthesis of 2D nanomaterial and their application in opto-electronic devices and sensing
- Author
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Amandeep Singh Pannu
- Published
- 2021
15. e-MagnetoMethyl IP: a magnetic nanoparticle-mediated immunoprecipitation and electrochemical detection method for global DNA methylation
- Author
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Ayad Saeed, Prashant Sonar, Fatema Zerin Farhana, Muhammad Umer, Amandeep Singh Pannu, Shakhawat H. Firoz, Sediqa Husaini, and Muhammad J. A. Shiddiky
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Immunoprecipitation ,02 engineering and technology ,Biochemistry ,Analytical Chemistry ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,law ,Electrochemistry ,Environmental Chemistry ,Methylated DNA immunoprecipitation ,Magnetite Nanoparticles ,Spectroscopy ,Polymerase chain reaction ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Chromatography ,Reproducibility of Results ,Electrochemical Techniques ,DNA Methylation ,021001 nanoscience & nanotechnology ,Bisulfite ,genomic DNA ,Enzyme ,chemistry ,DNA methylation ,0210 nano-technology ,DNA - Abstract
The quantification of global 5-methylcytosine (5mC) content has emerged as a promising approach for the diagnosis and prognosis of cancers. However, conventional methods for the global 5mC analysis require large quantities of DNA and may not be useful for liquid biopsy applications, where the amount of DNA available is limited. Herein, we report magnetic nanoparticles-assisted methylated DNA immunoprecipitation (e-MagnetoMethyl IP) coupled with electrochemical quantification of global DNA methylation. Carboxyl (-COOH) group-functionalized iron oxide nanoparticles (C-IONPs) synthesized by a novel starch-assisted gel formation method were conjugated with anti-5mC antibodies through EDC/NHS coupling (anti-5mC/C-IONPs). Anti-5mC/C-IONPs were subsequently mixed with DNA samples, in which they acted as dispersible capture agents to selectively bind 5mC residues and capture the methylated fraction of genomic DNA. The target-bound Anti-5mC/C-IONPs were magnetically separated and directly adsorbed onto the gold electrode surface using gold-DNA affinity interaction. The amount of DNA adsorbed on the electrode surface, which corresponds to the DNA methylation level in the sample, was electrochemically estimated by differential pulse voltammetric (DPV) study of an electroactive indicator [Ru(NH3)6]3+ bound to the surface-adsorbed DNA. Using a 200 ng DNA sample, the assay could successfully detect differences as low as 5% in global DNA methylation levels with high reproducibility (relative standard deviation (% RSD) =
- Published
- 2021
16. Co‐Electrodeposition of Nanostructured Ce‐NiO x on Stainless‐Steel Substrates for the Oxygen Evolution Reaction under Alkaline Conditions
- Author
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Daniel K. Sarfo, Priyanka Swarnkar, Thirumalachari Sundararajan, Amandeep Singh Pannu, Thomas J. Rainey, and Anthony P. O'Mullane
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Tafel equation ,Materials science ,Electrolysis of water ,Oxygen evolution ,02 engineering and technology ,Overpotential ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Catalysis ,Chemical engineering ,Mechanics of Materials ,Oxidation state ,General Materials Science ,0210 nano-technology ,Layer (electronics) - Abstract
The development of cost-effective catalysts that can be fabricated at scale for electrochemical water oxidation is an ongoing challenge. Here it is shown that stainless-steel AISI316 is an appropriate support electrode for a co-electrodeposited Ni-CeOx catalyst for the oxygen evolution reaction (OER) under alkaline conditions. Optimal OER performance is achieved via a cyclic voltammetric deposition protocol rather than constant potential deposition for the catalyst layer. An overpotential of 300 mV at a current density of 10 mA cm−2 is recorded with a Tafel slope of 43 mV dec−1 while the catalyst also demonstrates long-term stability. It is also found that the catalyst layer changes significantly after the OER. This includes changes to the catalyst morphology, distribution of oxidation state, and speciation as well as the transformation from an entirely amorphous material into one containing crystalline regions. This simple one-step electrodeposition process on a cost-effective substrate should, in principle, facilitate the fabrication of low-cost electrolyzers.
- Published
- 2021
17. Potassium Doping to Enhance Green Photoemission of Light‐Emitting Diodes Based on CsPbBr 3 Perovskite Nanocrystals
- Author
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Minh Tam Hoang, Amandeep Singh Pannu, Xiaoxiang Wang, Ke Gui, Yang Yang, Prashant Sonar, Soniya D. Yambem, Cheng Tang, Hongxia Wang, Ngoc Duy Pham, and Aijun Du
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Materials science ,Photoluminescence ,Dopant ,business.industry ,Band gap ,Doping ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Polystyrene sulfonate ,chemistry.chemical_compound ,chemistry ,law ,Optoelectronics ,Quantum efficiency ,0210 nano-technology ,business ,Perovskite (structure) ,Light-emitting diode - Abstract
Metal halide perovskite nanocrystals (PeNCs) are emerging as one of the most promising materials for optoelectrical devices such as light-emitting diode (LED) owing to their tunable band gaps, high color purity, and tolerance to defects. Nevertheless, the materials have not yet demonstrated their full potential in practical applications due to the poor stability of PeNCs and their unsatisfactory performance in devices. In this research, LED devices based on CsPbBr3 NCs are successfully demonstrated as an active light-emitting layer with enhanced efficiency via potassium doping. The study of the effect of potassium dopant on physicochemical properties of inorganic CsPbBr3 PeNCs shows that potassium cations (K+) remain in the crystal structure of perovskite compound as interstitial defects, which results in better coverage of surface ligands on the PeNCs and improved energy band alignment with adjacent electron injection layer (2,2′,2′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) and hole injection layer (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in an LED. As a consequence, the green LED with the K-doped CsPbBr3 PeNCs shows luminance up to 5759 cd m-2 and external quantum efficiency (EQE) of 5.6%, which is superior to the pristine device without K-doping (luminance: 4579 cd m-2, EQE: 4.8%).
- Published
- 2020
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