A Ni-based redox-active metal-organic framework for sensitive and non-enzymatic detection of glucose

Lopa, Nasrin Siraj,Rahman, Md. Mahbubur,Ahmed, Faiz,Sutradhar, Sabuj Chandra,Ryu, Taewook,Kim, Whangi Elsevier 2018 Journal of Electroanalytical Chemistry Vol.822 No.-

<P><B>Abstract</B></P> <P>Novel redox-active materials with the high surface area have great potential for electrochemical biosensors. In this research, we demonstrate the utilization of Ni<SUB>2</SUB>(dihydroxyterephthalic acid) (also known as CPO-27-Ni<SUP>II</SUP> and MOF-74-Ni<SUP>II</SUP>) metal-organic framework for non-enzymatic detection of glucose. CPO-27-Ni<SUP>II</SUP> is synthesized by ultrasound assisted solvothermal method with high purity, crystallinity, and large surface area. The CPO-27-Ni<SUP>II</SUP>-modified glassy carbon electrode (GCE) shows excellent redox activity in the alkaline medium due to the formation of Ni<SUP>II</SUP>/Ni<SUP>III</SUP> redox pair in CPO-27-Ni<SUP>II</SUP>. This corroborates the direct oxidation of glucose to gluconolactone. The sensor exhibits wide linear range with high sensitivity (ca. 40.95 μA/mM), and low method detection limit (MDL) (ca. 1.46 μM). The justification of this sensing platform was evaluated by standard addition method. Thus, the present biosensor could be used for the point of care detection of glucose.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CPO-27-Ni<SUP>II</SUP> MOF was utilized for direct oxidation of glucose. </LI> <LI> The redox processes of Ni<SUP>II/III</SUP> in CPO-27-Ni<SUP>II</SUP> have induced the direct oxidation of glucose. </LI> <LI> The sensor showed enhanced sensitivity, good electrochemical stability, and reproducibility. </LI> <LI> Validation with the determination of glucose in diluted human serum samples showed good recoveries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A chemically and electrochemically stable, redox-active and highly sensitive metal azolate framework for non-enzymatic electrochemical detection of glucose

Lopa, Nasrin Siraj,Rahman, Md. Mahbubur,Ahmed, Faiz,Ryu, Taewook,Lei, Jin,Choi, Inhwan,Kim, Dae Ho,Lee, Yong Hoon,Kim, Whangi Elsevier 2019 Journal of Electroanalytical Chemistry Vol.840 No.-

<P><B>Abstract</B></P> <P>Herein, we demonstrated the development of a non-enzymatic glucose sensor based on a metal azolate framework (MAF-4-Co<SUP>II</SUP> or Co(mim)<SUB>2</SUB>, mim=2-methylimidazole)-modified glassy carbon electrode (GCE). The as-synthesized MAF-4-Co<SUP>II</SUP> exhibited high crystallinity, purity, and chemical and electrochemical stability, which was characterized by various analytical methods. The MAF-4-Co<SUP>II</SUP> exhibited good redox activity in the alkaline medium due to the formation of MAF-4-Co<SUP>II</SUP>/MAF-4-Co<SUP>III</SUP> redox pair, which concurrently induced the non-enzymatic oxidation of glucose to gluconolactone. The MAF-4-Co<SUP>II</SUP>/GCE sensor exhibited wide dynamic ranges in the concentration range from 2 to 50μM and 100 to 1800μM with high sensitivity (ca. 990.90 and 30.95μA/cm<SUP>2</SUP>/mM, respectively), low detection limit (ca. 0.60μM), reproducibility, and selectivity. The practical applicability of this sensor was evaluated using diluted human serum samples, which revealed excellent recoveries of glucose. Thus, MAF-4-Co<SUP>II</SUP> can be used as a promising electrocatalyst for non-enzymatic detection of glucose with high stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MAF-4-Co<SUP>II</SUP> is utilized for non-enzymatic oxidation of glucose. </LI> <LI> The redox process of Co<SUP>II/III</SUP> in MAF-4 enables the oxidation of glucose. </LI> <LI> The MAF-4-Co<SUP>II</SUP>/GCE sensor shows high sensitivity, stability, and reproducibility. </LI> <LI> The sensor shows excellent recoveries of glucose in real sample analysis. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A base-stable metal-organic framework for sensitive and non-enzymatic electrochemical detection of hydrogen peroxide

Lopa, Nasrin Siraj,Rahman, Md. Mahbubur,Ahmed, Faiz,Chandra Sutradhar, Sabuj,Ryu, Taewook,Kim, Whangi Elsevier 2018 ELECTROCHIMICA ACTA Vol.274 No.-

<P><B>Abstract</B></P> <P>Stability of metal-organic frameworks (MOFs) in aqueous medium and extreme solution conditions (acidic or basic) are important for the development of stable, reproducible, and sensitive electrochemical biosensors. Herein, a base-stable chromium(III) dicarboxylate MOF was synthesized by microwave assisted solvothermal method for non-enzymatic detection of hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>). The as-synthesized MOF exhibited excellent base stability without any obvious changes in crystallinity, morphology, and spectroscopic behaviors after base treatment. This MOF-modified glassy carbon electrode showed negligible change in charge transfer resistance at the electrode|electrolyte interface after redox cycling and good catalytic activity for the reduction of H<SUB>2</SUB>O<SUB>2</SUB> in 0.1 M NaOH<SUB>(aq.)</SUB>. The enhanced catalytic activity of H<SUB>2</SUB>O<SUB>2</SUB> reduction is enabled by the redox process of Cr<SUP>III/II</SUP> in the chromium (III) dicarboxylate. The sensor showed the sensitivity of ca. 11.9 μA mM<SUP>−1</SUP>, wide linear range from 25 to 500 μM, and a method detection limit of ca. 3.52 μM. The validation of this sensing platform was evaluated by standard addition method. Thus, the present biosensor could be used for the point of care detection of H<SUB>2</SUB>O<SUB>2</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Cr-MOF (MIL-53-Cr<SUP>III</SUP>) was utilized for H<SUB>2</SUB>O<SUB>2</SUB> sensing for the first time. </LI> <LI> The Cr-MOF exhibits high chemical and electrochemical stability in NaOH solution. </LI> <LI> The redox processes of Cr<SUP>III/II</SUP> in MIL-53-Cr<SUP>III</SUP> have induced the direct reduction of H<SUB>2</SUB>O<SUB>2</SUB>. </LI> <LI> The sensor shows a wide linear range, good sensitivity, and low method detection limit. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Simple, low-cost, sensitive and label-free aptasensor for the detection of cardiac troponin I based on a gold nanoparticles modified titanium foil

Lopa, Nasrin Siraj,Rahman, Md. Mahbubur,Ahmed, Faiz,Ryu, Taewook,Sutradhar, Sabuj Chandra,Lei, Jin,Kim, Jaewoong,Kim, Dae Ho,Lee, Yong Hoon,Kim, Whangi Elsevier 2019 Biosensors & bioelectronics Vol.126 No.-

<P><B>Abstract</B></P> <P>This research demonstrated the electrochemical modification of low-cost titanium (Ti) metal substrate with gold nanoparticles (AuNPs) for the aptamer-based detection of cardiac troponin I (cTnI). AuNPs were deposited onto Ti sheets by the potential-step deposition method with high density and homogeneity as well as good crystallinity. It was then applied as a transducer to immobilize a thiol-functionalized DNA aptamer via the self-assembled monolayer mechanism for the specific binding of cTnI. This was verified through electrochemical and morphological analyses. The aptasensor could detect cTnI in a linear range of 1–1100 pM with a detection limit of ca. 0.18 pM. The aptasensor showed high sensitivity and specificity to cTnI over other interfering compounds with good recoveries in the diluted human serum samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AuNPs modified Ti foil is prepared for the aptamer-based detection of cTnI. </LI> <LI> High-density AuNPs allows maximizing the immobilization of cTnI-binding aptamers. </LI> <LI> The oxidation signal variation of [Fe(CN)<SUB>6</SUB>]<SUP>3-/4-</SUP> with [cTnI] enables to detect cTnI. </LI> <LI> This simple and low-cost aptasensor shows good analytical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly sensitive and simultaneous detection of dopamine and uric acid at graphene nanoplatelet-modified fluorine-doped tin oxide electrode in the presence of ascorbic acid

Rahman, Md. Mahbubur,Lopa, Nasrin Siraj,Ju, Myung Jong,Lee, Jae-Joon Elsevier 2017 Journal of Electroanalytical Chemistry Vol.792 No.-

<P><B>Abstract</B></P> <P>We developed a graphene nanoplatelet-modified fluorine-doped tin oxide electrode (GNP/FTO) for the simultaneous detection of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) and investigated the interaction mechanisms of DA, UA, and AA with GNPs considering their charging states at different pH values. Owing to the unique structure and properties originating from the oxygen and nitrogen functional groups at the edges, GNPs showed high electrocatalytic activity for the electrochemical oxidations of AA, DA, and UA with peak-to-peak potential separations (Δ<I>E</I> <SUB> <I>P</I> </SUB>) between AA-DA and DA-UA of <I>ca</I>. 0.23 and 0.17V, respectively. These values are sufficiently high to allow the simultaneous detection of DA and UA without interference from AA. The highly sensitive and stable GNP/FTO sensor showed sensitivities of <I>ca</I>. 0.15±0.004 and 0.14±0.007μA/μM, respectively, with detection limits of <I>ca</I>. 0.22±0.009 and 0.28±0.009μM, respectively, for DA and UA. The sensor could detect DA and UA concentrations in human serum samples with excellent recoveries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FTO was modified with graphene nanoplatelets (GNPs) by the e-spray method. </LI> <LI> Dopamine and uric acid were simultaneously detected with GNP/FTO without interference from ascorbic acid. </LI> <LI> Sensor allows low detection limits of 0.22 and 0.28μM for dopamine and uric acid, respectively. </LI> <LI> Sensor shows good stability and recoveries from human serum samples. </LI> <LI> The interaction mechanisms between dopamine, uric acid, and ascorbic acid with GNPs were discussed and verified. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Label-Free DNA Hybridization Detection by Poly(Thionine)-Gold Nanocomposite on Indium Tin Oxide Electrode

Rahman, Md. Mahbubur,Lopa, Nasrin Siraj,Kim, Young Jun,Choi, Dong-Kug,Lee, Jae-Joon The Electrochemical Society 2016 Journal of the Electrochemical Society Vol.163 No.5

<P>A simple and label-free electrochemical DNA hybridization sensor was developed based on a poly(thionine)/gold nanoparticle composite-modified indium tin oxide (PTH/GNPs/ITO) electrode. The PTH/GNPs/ITO electrode was prepared by the electrode position of GNPs on ITO followed by the electropolymerization of thionine (TH). Probe DNA (pDNA) was immobilized on this substrate via covalent linkage between the -NH2 group of PTH and the PO43- group at the 5' end of pDNA. The immobilized single-strand pDNA increased the stiffness of the PTH film and decreased the PTH oxidation current, whereas the current was reduced to a greater extent after the formation of double-strand DNA by the hybridization of target complementary DNA (cDNA). The pDNA/PTH/GNPs/ITO sensor exhibited excellent stability, and selectivity to discriminate DNA base pair mismatches. The semi-log plot of the [cDNA] vs. oxidation current of PTH was linear in the concentration range of 1 mu M - 1 fM with the detection limit (S/N = 3) and sensitivity of ca. 0.3 fM and ca. 2.0 mu A . cm(-2) . fM(-1), respectively. (C) 2016 The Electrochemical Society. All rights reserved.</P>

Advances in electrochemical aptasensing for cardiac biomarkers

Rahman Md. Mahbubur,Lopa Nasrin Siraj,Lee Jae‐Joon 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.1

Novel bio-receptors or bio-recognition molecular markers with high specificity, stability, and affinity for the efficient binding and entrapment of target biomolecules are essential for developing biomedical devices with high sensitivity and reliability. Aptamers are peptide or nucleic-acid (DNA or RNA) molecules capable of binding to target biomarkers by forming a unique three-dimensional structure, providing an effective platform for biosensing. This review comprehensively summarizes the progress of label-free and label-based electrochemical aptasensors for the detection of various biomarkers related to cardiovascular diseases. It also outlines the fundamental properties of different cardiac biomarkers, synthesis of target-specific aptamers, and working principles, such as single receptor and sandwich, of the different types of sensing assays for the electrochemical detection of cardiac biomarkers while highlighting the current challenges and future perspectives.

The Mutation that Makes Escherichia coli Resistant to λ P Gene-mediated Host Lethality Is Located within the DNA Initiator Gene dnaA of the Bacterium

( Indrani Datta ),( Sarbani Banik Maiti ),( Lopa Adhikari ),( Subrata Sau ),( Niranjan Das ),( Nitai Chandra Mandal ) 생화학분자생물학회 2005 BMB Reports Vol.38 No.1

Earlier, we reported that the bacteriophage λ P gene product is lethal to Escherichia coli, and the E. coli rpl mutants are resistant to this λP gene-mediated lethality. In this paper, we show that under the λ P gene-mediated lethal condition, the host DNA synthesis is inhibited at the initiation step. The rpl8 mutation maps around the 83 min position in the E. coli chromosome and is 94% linked with the dnaA gene. The rpl8 mutant gene has been cloned in a plasmid. This plasmid clone can protect the wild-type E. coli from λ P gene-mediated killing and complements E. coli dnaAts46 at 42℃. Also, starting with the wild-type dnaA gene in a plasmid, the rpl-like mutations have been isolated by in vitro mutagenesis. DNA sequencing data show that each of the rpl8, rp112 and rp114 mutations has changed a single base in the dnaA gene, which translates into the amino acid changes N313T, Y200N, and S246T respectively within the DnaA protein. These results have led us to conclude that the rpl mutations, which make E. coli resistant to λ P gene-mediated host lethality, are located within the DNA initiator gene dnaA of the host.

Electrodeposition of Gold on Fluorine-Doped Tin Oxide: Characterization and Application for Catalytic Oxidation of Nitrite

Rahman, Md. Mahbubur,Li, Xiao-Bo,Lopa, Nasrin Siraj,Lee, Jae-Joon Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.7

Sub-micrometer size gold particles were electrodeposited on a transparent fluorine-doped tin oxide (FTO) from acetonitrile solution containing $AuCl_4{^-}$ and tetramethylammonium tetraflouroborate (TMATFB) for detecting $NO_2{^-}$. A series of two-electron ($2e^-$) and one-electron ($1e^-$) reductions of the $AuCl_4{^-}-AuCl_2{^-}-Au$ redox systems were observed at FTO and a highly stable and homogeneous distribution of Au on FTO (Au/FTO) was obtained by stepping the potential from 0 to -0.55 V (vs. Ag/$Ag^+$). The Au/FTO electrode exhibited sufficiently high catalytic activity toward the oxidation of $NO_2{^-}$ with a detection limit (S/N = 3) and sensitivity of 2.95 ${\mu}M$ and 223.4 ${\mu}A{\cdot}cm^{-2}{\cdot}mM^{-1}$, respectively, under optimal conditions. It exhibited an interference-free signal for $NO_2{^-}$ detection with excellent recoveries from real samples.

Synthesis and characterization of fluorosulfonyl imide isatin biphenylene block copolymer for PEMFC

Ryu, Taewook,Chandra, Sabuj Sutradhar,Ahmed, Faiz,Lopa, Nasrin Siraj,Yoon, Soojin,Yang, Hanmo,Lee, Seungchan,Choi, Inhwan,Kim, Whangi Elsevier 2018 International journal of hydrogen energy Vol.43 No.26

<P><B>Abstract</B></P> <P>In this study, A fluorosulfonyl imide-containing precursor derived from fluorosulfonyl isocyanate was synthesized and grafted on poly (isatin-biphenylene) random and block copolymers. The carbon-carbon structured poly (isatin biphenylene)s were prepared by super acid catalyzed polyhydroxyalkylation reaction with istain, 2,2′-biphenyl, 2,2′-dihydroxybiphenyl. A fluorosulfonyl imide-containing precursor was prepared from chlorosulfuric acid and fluorosulfonylisocyanate. Fluorosulfonyl imide group have higher acidity than sulfonic acid group, therefore the membranes containing fluorosulfonyl imide groups instead of sulfonic acid groups were studied. These membranes showed slightly higher performance of proton conductivity, low water uptake, and good dimensional stability. The structure of the synthesized polymer was investigated by <SUP>1</SUP>H NMR spectroscopy. Surface morphologies will also be assessed by atomic force microscope (AFM). Microphase-separated block copolymers are preferred over random copolymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Block and random copolymers were synthesized from biphenyl, 2,2′-biphenol and isatin via super acid catalyzed. </LI> <LI> Fluorosulfonyl imide super strong acid was grafted on copolymers instead of sulfonic acid. </LI> <LI> Block copolymer showed better proton conductivity, physical, and chemical stability than random copolymer. </LI> <LI> Block copolymer showed the IEC and water uptake value 1.45 meq./g and 19.14% respectively. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Random and block copolymers successfully synthesized from isatin, biphenyl and 2.2′-biphenol with super acid catalyst. Block copolymer membranes show higher proton conductivity than random copolymers. The block copolymer showed the IEC value 1.45 meq./g, water uptake 19.14% and the proton conductivity 78.89 mS/cm at 80 °C under 90% RH. Block copolymer membrane showed a greater dependence of proton conductivity on the relative humidity, and had higher conductivity and cell performance than that of random copolymer with similar IEC value. These results showed that the morphology of polymer matrix greatly affected the cell performance and membrane with well-separated hydrophilic/hydrophobic phase is very important in the fuel cell application. This research demonstrated the possibility of promising BPIIB membranes for excellent proton conductivity and cell performance.</P> <P>[DISPLAY OMISSION]</P>