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>

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>

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>

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>

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>

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.

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>

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

Mohammad Mahbubur Rahman,Xiao-Bo Li,Nasrin Siraj Lopa,이재준 대한화학회 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 AuCl4 − and tetramethylammonium tetraflouroborate (TMATFB) for detecting NO2 −. A series of two-electron (2e−) and one-electron (1e−) reductions of the AuCl4 −-AuCl2 −-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 NO2 − with a detection limit (S/N = 3) and sensitivity of 2.95 μM and 223.4 μA·cm−2·mM−1, respectively, under optimal conditions. It exhibited an interference-free signal for NO2 − detection with excellent recoveries from real samples.

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 block copolymer and comparative study with random copolymer via superacid–catalyzed reaction

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

<P><B>Abstract</B></P> <P>The grafted block copolymer based polymer electrolyte membrane (PEM) was successfully synthesized by the superacid-catalyzed polyhydroxyalkylation reaction from biphenyl, 2,2′-biphenol and isatin and the performance of the block copolymer were compared in conjunction with the random copolymer. These polymers have all carbon-carbon structure on polymer backbone without ether linkage. The bromoalkylsulfone potassium salt was prepared from 1,3-propane sultone and potassium bromide. Particularly, the attached alkyl sulfone groups were afforded better stability due to less reactivity towards nucleophilic substitution reaction. Moreover, the block copolymer exhibited better proton conductivity (76.84 mS/cm under 90% relative humidity at 80 <SUP>°</SUP>C), water resistivity, chemical, and thermal stability compared to the random copolymer, because block copolymer membranes showed good hydrophilic/hydrophobic phase separation and wide ionic channels. The structures of the resultant PEMs were confirmed by <SUP>1</SUP>H NMR spectroscopy and thermogravimetric analysis (TGA). These membranes were studied by proton conductivity, water uptake (WU), and ion exchange capacity (IEC). Fenton test was attended by Fenton's reagent (4 ppm Fe<SUP>2+</SUP>, 3% H<SUB>2</SUB>O<SUB>2</SUB>) for confirmation of the polymer degradation and the surface morphology of membranes was also analyzed by atomic force microscope.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The grafted block copolymer was synthesized via super acid catalyzed reaction. </LI> <LI> The properties of the block copolymer were compared in conjunction with random copolymer. </LI> <LI> Block copolymer exhibited better cell performance compared to random copolymer. </LI> <LI> Grafted block copolymer showed 18.75% water uptake. </LI> </UL> </P>