scholarly journals A Novel Application of Electroactive Polyimide Doped with Gold Nanoparticles: As a Chemiresistor Sensor for Hydrogen Sulfide Gas

2019 ◽  
Author(s):  
Lee Marvin G. Padua ◽  
Jui-Ming Yeh ◽  
Karen S. Santiago
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Sulfide ◽  
Limit Of Detection ◽  
Average Diameter ◽  
Potential Candidate ◽  
Theoretical Limit ◽  
Work Related ◽  
Diffraction Peaks ◽  
Linear Concentration Range ◽  
Linear Concentration

This research paper presents a new application of electroactive polyimide doped with gold nanoparticles (PI/AuNPs) as a chemiresistor sensor for detecting hydrogen sulfide gas. The synthesis of PI/AuNPs was done in a simple 3-step process of polymerization using the as prepared amine-capped aniline trimer (ACAT), followed by imidization, and doping. Spectral analyses via FTIR, LC-MS and 1H-NMR confirmed the formation of amine-capped aniline trimer with a MW of 288 g mol-1. Comparison of ACAT, BSAA, and PI FTIR spectra showed successful polymerization of the last, while XRD validated the incorporation of metal nanoparticles onto the polymer matrix showing characteristic diffraction peaks corresponding to gold. Furthermore, TEM, and FE-SEM revealed the presence of well-dispersed Au nanoparticles with an average diameter of about 60nm. The electroactive PI/AuNPs-based sensor showed a sensitivity of 0.29% ppm-1 H2S at a linear concentration range of 50 to 300 ppm H2S (r = 0.9777). The theoretical limit of detection was found at 0.142 ppm or 142 ppb H2S gas. The sensor provided a stable response reading at an average response time of 43±5 seconds, which was easily recovered after an average time of 99±5 seconds. The sensor response was highly repeatable and reversible with RSD values of 8.88%, and 8.60%, respectively. Compared with the performance of the conventional conducting polyaniline also doped with gold nanoparticles (PANI/AuNPs), the fabricated electroactive PI/AuNPs exhibited improved sensing performance making it a potential candidate in monitoring H2S in the environment and for work-related safety.

scholarly journals A Novel Application of Electroactive Polyimide Doped with Gold Nanoparticles: As a Chemiresistor Sensor for Hydrogen Sulfide Gas

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1918 ◽  
Author(s):  
Lee Marvin G. Padua ◽  
Jui-Ming Yeh ◽  
Karen S. Santiago
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Sulfide ◽  
Limit Of Detection ◽  
Average Diameter ◽  
Potential Candidate ◽  
Theoretical Limit ◽  
Work Related ◽  
Diffraction Peaks ◽  
Linear Concentration Range ◽  
Linear Concentration

This research paper presents a new application of electroactive polyimide doped with gold nanoparticles (PI/AuNPs) as a chemiresistor sensor for detecting hydrogen sulfide gas. The synthesis of PI/AuNPs was done in a simple 3-step process of polymerization using the as prepared amine-capped aniline trimer (ACAT), followed by imidization, and doping. Spectral analyses via FTIR, LC-MS and 1H-NMR confirmed the formation of amine-capped aniline trimer with a MW of 288 g mol−1. Comparison of ACAT, BSAA, and PI FTIR spectra showed successful polymerization of the last, while XRD validated the incorporation of metal nanoparticles onto the polymer matrix, showing characteristic diffraction peaks corresponding to gold. Furthermore, TEM, and FE-SEM revealed the presence of well-dispersed Au nanoparticles with an average diameter of about 60 nm. The electroactive PI/AuNPs-based sensor showed a sensitivity of 0.29% ppm−1 H2S at a linear concentration range of 50 to 300 ppm H2S (r = 0.9777). The theoretical limit of detection was found at 0.142 ppm or 142 ppb H2S gas. The sensor provided a stable response reading at an average response time of 43 ± 5 s, which was easily recovered after an average time of 99 ± 5 s. The sensor response was highly repeatable and reversible, with RSD values of 8.88%, and 8.60%, respectively. Compared with the performance of the conventional conducting polyaniline also doped with gold nanoparticles (PANI/AuNPs), the fabricated electroactive PI/AuNPs exhibited improved sensing performance making it a potential candidate in monitoring H2S in the environment and for work-related safety.

scholarly journals Advantages of Highly Spherical Gold Nanoparticles as Labels for Lateral Flow Immunoassay

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3608
Author(s):  
Nadezhda A. Byzova ◽  
Anatoly V. Zherdev ◽  
Boris N. Khlebtsov ◽  
Andrey M. Burov ◽  
Nikolai G. Khlebtsov ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Troponin I ◽  
Limit Of Detection ◽  
Average Diameter ◽  
Covalent Immobilization ◽  
Lateral Flow ◽  
Antibody Immobilization ◽  
Site Testing ◽  
Spherical Gold Nanoparticles

The use of lateral flow immunoassays (LFIAs) for rapid on-site testing is restricted by their relatively high limit of detection (LoD). One possible way to decrease the LoD is to optimize nanoparticle properties that are used as labels. We compare two types of Au nanoparticles: usual quasispherical gold nanoparticles (C-GNPs), obtained by the Turkevich–Frens method, and superspherical gold nanoparticles (S-GNPs), obtained by a progressive overgrowth technique. Average diameters were 18.6–47.5 nm for C-GNPs and 20.2–90.4 nm for S-GNPs. Cardiomarker troponin I was considered as the target analyte. Adsorption and covalent conjugation with antibodies were tested for both GNP types. For C-GNPs, the minimal LoD was obtained with 33.7 nm nanoparticles, reaching 12.7 ng/mL for covalent immobilization and 9.9 ng/mL for adsorption. The average diameter of S-GNPs varied from 20.2 to 64.5 nm, which resulted in a decrease in LoD for an LFIA of troponin I from 3.4 to 1.2 ng/mL for covalent immobilization and from 2.9 to 2.0 ng/mL for adsorption. Thus, we obtained an 8-fold decrease in LoD (9.9 to 1.2 ng/mL) by using S-GNPs. This effect can be related to more effective antibody immobilization and improved S-GNP optical properties. The obtained results can improve LFIAs for various practically significant analytes.

scholarly journals TEKNIK VOLTAMETRI PELUCUTAN ANODIK GELOMBANG PERSEGI UNTUK PENENTUAN KADAR LOGAM Cu DALAM KANGKUNG AIR

2016 ◽  
Vol 1 (2) ◽  
pp. 122
Author(s):  
Irdhawati Irdhawati ◽  
Liana Sari ◽  
Ida Ayu Raka Astiti Asih
Keyword(s):  
Limit Of Detection ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Water Spinach ◽  
Square Wave ◽  
Anodic Stripping ◽  
Standard Solution ◽  
Linear Concentration Range ◽  
Linear Concentration

ABSTRAK Analisis logam berat Cu(II) dilakukan dengan metode voltametri pelucutan anodik gelombang persegi. Penelitian ini bertujuan untuk mengetahui validitas metode voltametri pelucutan anodik yang digunakan dalam pengukuran kadar logam Cu(II) dalam sampel kangkung air di muara sungai Badung. Elektroda glassy carbon digunakan sebagai elektroda kerja, Ag/AgCl sebagai elektroda pembanding, dan kawat platina sebagai elektroda pembantu. Parameter yang dioptimasi meliputi waktu deposisi dan laju pindai dalam larutan standar Cu(II) 500 ppb. Validasi metode ditentukan dengan menentukan rentang konsentrasi linier, limit deteksi, keberulangan pengukuran, dan persen perolehan kembali. Teknik voltametri pelucutan anodik kemudian digunakan untuk mengukur kadar logam Cu(II) pada sampel kangkung air.Hasil optimasi pengukuran kadar logam Cu(II) yaitu waktu deposisi optimum 60 detik dan laju pindai optimum 10 mV/detik. Pengukuran validitas larutan standar logam Cu(II), rentang konsentrasi linier larutan 50 ~500 ppb dan memiliki nilai koefisien korelasi 0,9983. Limit deteksi 35 ppb, keberulangan pengukuran memiliki rasio Horwitz kurang dari 2, dan persen perolehan kembali 99,35% ± 0,4526. Hasil pengukuran sampel tanaman kangkung memiliki kandungan logam Cu(II) sebesar 4,0 ppm. Berdasarkan Keputusan Direktur Jenderal Pengawasan Obat dan Makanan batas maksimum cemaran logam dalam makanan untuk logam Cu(II) adalah 5,0 ppm. Oleh karena itu dapat diketahui bahwa kandungan logam Cu(II) tidak melebihi kadar maksimum yang diperkenankan. Kata Kunci : logam berat, voltametri pelucutan anodik gelombang persegi, kangkung airABSTRACTHeavy metal analysis of Cu(II) was measured by square wave anodic stripping voltammetry method. The aim of this research is to know the validity of square wave anodic stripping voltammetry method for determination of Cu(II) in water spinach from the estuary of  Badung river. Glassy carbon, Ag/AgCl, and Pt wire electrodes were used as working electrode, reference electrode and counter electrode, respectively. Optimized parameter involved the deposition time and scan rate in standard solution Cu(II) 500 ppb. Furthermore, the validation method was examined by determination of linear concentration range, limit of detection, repetition of measurement, and percent of recovery. Moreover, the result of validation was used for observing of heavy metal Cu(II) content in water spinach.             The result of optimum deposition time is 60 s. Meanwhile, the scan rate optimum is 10 mV/s. Measurement for standard solution 50 ~ 500 ppb on linear concentration range, with correlation coefficient 0,9983. Limit of detection is 35 ppb, repetition of measurement for metal has Horwitz ratio less than 2, and percent recovery of Cu(II) measurement is 99,35% ± 0,4526. The measurement of Cu(II) content in the water spinach sample contain Cu(II) 4,0 ppm. Based on Decree of Directorate General for Drug and Food Control, the treshold line for Cu(II) contamination for food is 5,0 ppm. Therefore, the water spinach sample contain Cu(II) is less than accepted value. Keyword : Heavy metal, square wave anodic stripping voltammetry, water spinach

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe

2020 ◽  
Vol 17 ◽  
Author(s):  
Mansureh Alizadeh ◽  
Mandana Amiri ◽  
Abolfazl Bezaatpour
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Cathodic Peak ◽  
Easy Method ◽  
Peak Current ◽  
Indirect Determination ◽  
Tract Infections

: Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10−8–1.0 × 10-7 M and 5.0 × 10−7–1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10−9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

scholarly journals Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 893
Author(s):  
Olufunto T. Fanoro ◽  
Sundararajan Parani ◽  
Rodney Maluleke ◽  
Thabang C. Lebepe ◽  
Jose R. Varghese ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Cell Viability ◽  
Leaf Extract ◽  
Room Temperature ◽  
Klebsiella Oxytoca ◽  
Cost Effective ◽  
Average Diameter ◽  
Antibacterial Activities ◽  
Inhibition Concentration ◽  
First Time

We herein report a facile, green, cost-effective, plant-mediated synthesis of gold nanoparticles (AuNPs) for the first time using Combretum erythrophyllum (CE) plant leaves. The synthesis was conducted at room temperature using CE leaf extract serving as a reducing and capping agent. The as-synthesized AuNPs were found to be crystalline, well dispersed, and spherical in shape with an average diameter of 13.20 nm and an excellent stability of over 60 days. The AuNPs showed broad-spectrum antibacterial activities against both pathogenic Gram-positive (Staphylococcus epidermidis (ATCC14990), Staphylococcus aureus (ATCC 25923), Mycobacterium smegmatis (MC 215)) and Gram-negative bacteria (Proteus mirabilis (ATCC 7002), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13822), Klebsiella oxytoca (ATCC 8724)), with a minimum inhibition concentration of 62.5 µg/mL. In addition, the as-synthesized AuNPs were highly stable with exceptional cell viability towards normal cells (BHK- 21) and cancerous cancer cell lines (cervical and lung cancer).

scholarly journals Gold nanoparticles reduce inflammation in cerebral microvessels of mice with sepsis

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Davide Di Bella ◽  
João P. S. Ferreira ◽  
Renee de Nazare O. Silva ◽  
Cinthya Echem ◽  
Aline Milan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gold Nanoparticles ◽  
Blood Vessels ◽  
Platelet Adhesion ◽  
Potential Candidate ◽  
Cerebral Blood Vessels ◽  
Cerebral Microvessels ◽  
Antibiotic Effect ◽  
Anti Inflammatory ◽  
20 Nm

Abstract Background Sepsis is an emergency medical condition that can lead to death and it is defined as a life-threatening organ dysfunction caused by immune dysregulation in response to an infection. It is considered the main killer in intensive care units. Sepsis associated-encephalopathy (SAE) is mostly caused by a sepsis-induced systemic inflammatory response. Studies report SAE in 14–63% of septic patients. Main SAE symptoms are not specific and usually include acute impairment of consciousness, delirium and/or coma, along with electroencephalogram (EEG) changes. For those who recover from sepsis and SAE, impaired cognitive function, mobility and quality of life are often observed months to years after hospital discharge, and there is no treatment available today to prevent that. Inflammation and oxidative stress are key players for the SAE pathophysiology. Gold nanoparticles have been demonstrated to own important anti-inflammatory properties. It was also reported 20 nm citrate-covered gold nanoparticles (cit-AuNP) reduce oxidative stress. In this context, we tested whether 20 nm cit-AuNP could alleviate the acute changes caused by sepsis in brain of mice, with focus on inflammation. Sepsis was induced in female C57BL/6 mice by cecal ligation and puncture (CLP), 20 nm cit-AuNP or saline were intravenously (IV) injected 2 h after induction of sepsis and experiments performed 6 h after induction. Intravital microscopy was used for leukocyte and platelet adhesion study in brain, blood brain barrier (BBB) permeability carried out by Evans blue assay, cytokines measured by ELISA and real time PCR, cell adhesion molecules (CAMs) by flow cytometry and immunohistochemistry, and transcription factors, by western blotting. Results 20 nm cit-AuNP treatment reduced leukocyte and platelet adhesion to cerebral blood vessels, prevented BBB failure, reduced TNF- concentration in brain, and ICAM-1 expression both in circulating polymorphonuclear (PMN) leukocytes and cerebral blood vessels of mice with sepsis. Furthermore, 20 nm cit-AuNP did not interfere with the antibiotic effect on the survival rate of mice with sepsis. Conclusions Cit-AuNP showed important anti-inflammatory properties in the brain of mice with sepsis, being a potential candidate to be used as adjuvant drug along with antibiotics in the treatment of sepsis to avoid SAE

Selective Colorimetric Detection of Hydrogen Sulfide Based on Primary Amine-Active Ester Cross-Linking of Gold Nanoparticles

2015 ◽  
Vol 87 (14) ◽  
pp. 7267-7273 ◽  
Author(s):  
Zhiqin Yuan ◽  
Fengniu Lu ◽  
Meihua Peng ◽  
Chia-Wei Wang ◽  
Yu-Ting Tseng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Sulfide ◽  
Primary Amine ◽  
Colorimetric Detection ◽  
Cross Linking ◽  
Active Ester

scholarly journals Quantification of DNA by a Thermal-Durable Biosensor Modified with Conductive Poly(3,4-ethylenedioxythiophene)

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3684 ◽  
Author(s):  
Yesong Gu ◽  
Po-Yuan Tseng ◽  
Xiang Bi ◽  
Jason Yang
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Complementary Sequence ◽  
Signal Decay ◽  
Target Dna ◽  
Hybridization Efficiency ◽  
Sh Group ◽  
Polymerase Chain ◽  
Or Gene

The general clinical procedure for viral DNA detection or gene mutation diagnosis following polymerase chain reaction (PCR) often involves gel electrophoresis and DNA sequencing, which is usually time-consuming. In this study, we have proposed a facile strategy to construct a DNA biosensor, in which the platinum electrode was modified with a dual-film of electrochemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) resulting in immobilized gold nanoparticles, with the gold nanoparticles easily immobilized in a uniform distribution. The DNA probe labeled with a SH group was then assembled to the fabricated electrode and employed to capture the target DNA based on the complementary sequence. The hybridization efficiency was evaluated with differential pulse voltammetry (DPV) in the presence of daunorubicin hydrochloride. Our results demonstrated that the peak current in DPV exhibited a linear correlation the concentration of target DNA that was complementary to the probe DNA. Moreover, the electrode could be reused by heating denaturation and re-hybridization, which only brought slight signal decay. In addition, the addition of the oxidized form of nicotinamide adenine dinucleotide (NAD+) could dramatically enhance the sensitivity by more than 5.45-fold, and the limit-of-detection reached about 100 pM.

scholarly journals Quantitative Determination of Azithromycin in Human Plasma by Liquid Chromatography–Mass Spectrometry and its Application in Pharmackokinetic Study

2012 ◽  
Vol 11 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Maizbha Uddin Ahmed ◽  
Mohammad Safiqul Islam ◽  
Tasmin Ara Sultana ◽  
AGM Mostofa ◽  
Muhammad Shahdaat Bin Sayeed ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Solid Phase ◽  
Internal Standard ◽  
Extraction Process ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Linear Concentration Range ◽  
Linear Concentration

Azithromycin is an effective and well-known antimicrobial agent. In the present study, a simple, sensitive and specific LC/MS/MS method has been developed and validated for the quantification of Azithromycin in  human serum samples using Clarithromycin as internal standard. Azithromycin was extracted from biological matrix  by using solid phase extraction process. The chromatographic separation was performed on Luna C18 (3 ?, 2x150   mm) column with a mobile phase consisting of 35 mM ammonium acetate buffer (mobile phase-A) and acetonitrile  and methanol in ratio of 90:10 ( as mobile phase-B) at a flow rate of 0.25 mL/min. The method was validated over a  linear concentration range of 0.5?50.0 ng/mL and limit of quantification (LOQ) was 0.5 ng/mL with a coefficient of  correlation (r2) = 0.9998. The intra-day and inter-day precision expressed as relative standard deviation were 1.64% – 8.43% and 2.32% – 9.92%, respectively. The average recovery of azithromycin from serum was 98.11%. The method  was successfully applied to a pharmacokinetic study after oral administration of Azithromycin 200 mg/5 ml suspension in healthy Bangladeshi volunteers. DOI: http://dx.doi.org/10.3329/dujps.v11i1.12488 Dhaka Univ. J. Pharm. Sci. 11(1): 55-63, 2012 (June)

scholarly journals Sandwich-Type DNA Micro-Optode Based on Gold–Latex Spheres Label for Reflectance Dengue Virus Detection

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1820
Author(s):  
Jeningsih ◽  
Ling Ling Tan ◽  
Alizar Ulianas ◽  
Lee Yook Heng ◽  
Nur-Fadhilah Mazlan ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Limit Of Detection ◽  
Virus Detection ◽  
Average Diameter ◽  
Optical Biosensor ◽  
Clinical Samples ◽  
Sandwich Hybridization ◽  
Latex Spheres ◽  
Sandwich Type ◽  
Thiol Binding

A DNA micro-optode for dengue virus detection was developed based on the sandwich hybridization strategy of DNAs on succinimide-functionalized poly(n-butyl acrylate) (poly(nBA-NAS)) microspheres. Gold nanoparticles (AuNPs) with an average diameter of ~20 nm were synthesized using a centrifugation-based method and adsorbed on the submicrometer-sized polyelectrolyte-coated poly(styrene-co-acrylic acid) (PSA) latex particles via an electrostatic method. The AuNP–latex spheres were attached to the thiolated reporter probe (rDNA) by Au–thiol binding to functionalize as an optical gold–latex–rDNA label. The one-step sandwich hybridization recognition involved a pair of a DNA probe, i.e., capture probe (pDNA), and AuNP–PSA reporter label that flanked the target DNA (complementary DNA (cDNA)). The concentration of dengue virus cDNA was optically transduced by immobilized AuNP–PSA–rDNA conjugates as the DNA micro-optode exhibited a violet hue upon the DNA sandwich hybridization reaction, which could be monitored by a fiber-optic reflectance spectrophotometer at 637 nm. The optical genosensor showed a linear reflectance response over a wide cDNA concentration range from 1.0 × 10−21 M to 1.0 × 10−12 M cDNA (R2 = 0.9807) with a limit of detection (LOD) of 1 × 10−29 M. The DNA biosensor was reusable for three consecutive applications after regeneration with mild sodium hydroxide. The sandwich-type optical biosensor was well validated with a molecular reverse transcription polymerase chain reaction (RT-PCR) technique for screening of dengue virus in clinical samples, e.g., serum, urine, and saliva from dengue virus-infected patients under informed consent.

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