BIOSENSORS & BIOELECTRONICS
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2014
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IF 6.451
Zhenting Yang,Jing Qian,Xingwang Yang,Ding Jiang,Xiaojiao Du,Kan Wang,Hanping Mao,Kun Wang
A facile aptasensor has been developed for the colorimetric detection of acetamiprid by using the hemin-functionalized reduced graphene oxide (hemin-rGO) composites. The as-prepared hemin-rGO composites possessed both the ability of rGO to physically adsorb the aptamers and the peroxidase-like activity of hemin that could catalyse 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 , to produce a solution with blue color. The well-dispersed hemin-rGO composites coagulated completely at the proper salt concentration ; however, the coagulation of hemin-rGO was vanished when abundant aptamers were adsorbed on its surface because the attached negatively charged DNA backbone increased individual hemin-rGO electrostatic repulsion . In the detection scheme, acetamiprid with different concentrations was firstly incubated with the same amount of aptamer. The more acetamiprid in the tested solution, the less free aptamers were absorbed on the hemin-rGO surface, making the composites coagulate to a higher degree in the presence of the optimum NaCl concentration. As a consequence, the content of hemin-rGO in the supernatant was decreased after centrifugation, which catalysed oxidation of TMB in the presence of H 2 O 2 to produce light blue color with a low absorbance. The color variation relavant to the acetamiprid concentration can be judged by the naked eyes and easily monitored by the inexpensive UV–vis spectrometer. Such designed aptasensor displayed a linear response for acetamiprid in the range from 100 nM to 10 μM with a detection limit of 40 nM ( S / N =3). This colorimetric aptasensing platform offers great advantages including the simple operation process, low-cost portable instrument, and user-friendly applications.
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Analytical Methods
·
2015
·Vol. 7
·期 21
·9340-9346
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IF 1.821
Kewei Wang,Na Sun,Xinpan Li,Ruihua Zhang,Guangyue Zu,Jine Wang,Renjun Pei
This study reported the development of a p–n heterojunction photoelectrochemical biosensor using a G-quadruplex as the recognition system. The n-type ZnO nanorods and p-type BiOI nanoflakes were combined to form the heterostructure by in situ growth of BiOI attributed to a simple impregnating-hydroxylation method. This simple p–n heterojunction fabrication method could facilitate the development of rapid and sensitive visible light activated PEC sensors. In this study, the ZnO/BiOI photoelectrode showed a rapid photocurrent decrease in the presence of Pb2+ due to the electron withdrawing effect of hemin which bound with the G-quadruplex/Pb2+ complex. This PEC biosensor exhibited a good response following the concentration of Pb2+ in the range from 10 to 100 μM.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Chang-Jie Gu,Fen-Ying Kong,Zhi-Dong Chen,Da-He Fan,Hai-Lin Fang,Wei Wang
A facile and effective strategy is demonstrated for the synthesis of ternary reduced graphene oxide-Hemin-Au (rGO-H-Au) nanohybrids . The nanohybrids were synthesized through a one-pot in situ reduction of GO and HAuCl 4 under alkaline conditions using GO, Hemin and HAuCl 4 as the starting materials. The synthesis process can be finished within 1 h in a solution phase, without adding any additional surfactant, stabilizing agent and toxic or harsh chemical reducing agents. The resulting nanohybrids were characterized by UV–vis spectroscopy, Raman spectroscopy , transmission electron microscopy (TEM), and so on. Electrochemical measurements showed that the rGO-H-Au nanohybrids exhibited good electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2 ). Based on this property, a simple and highly sensitive amperometric biosensor for H 2 O 2 had been developed. The linear relationships were obtained from 0.1 µM to 40 µM and the detection limit was estimated to be 30 nM. The simple and sensitive sensing platform showed great promising applications in the pharmaceutical, clinical and industrial detection of H 2 O 2 .
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POLYMER
·
2015
·
IF 3.562
Chun-Yu Zhang,Jing-Hui He,Cai-Jian Lu,Qian-Feng Gu,Lin-Xin Wu,Quan Liu,Hua Li,Qing-Feng Xu,Jian-Mei Lu
Two polymer-Hemin composites, AB type block copolymer (PStCH- b -P4VP): Hemin and homopolymer of poly(4-vinylpyridine) (P4VP): Hemin, can be fabricated into sandwich memory devices. The memory device characteristics of the PStCH- b -P4VP: Hemin blends can show Flash memory behavior, while the P4VP polymer with Hemin only shows write-once-read-many-times (WORM) performance. Charge transfer and nanocomposite redox are probably responsible for the conductance-switching behavior. The results of cyclic voltammogram (CV) measurement indicate that the reversible Fe III /Fe II redox reaction is preserved well in the composite PStCH- b -P4VP: Hemin, while only polymer oxidation is observed in the P4VP: Hemin system. Due to the hindrance of StCH moiety, the coordination of pyridine and Fe II can keep the Fe II active. The P4VP has a more flexible chain that saturates the Fe II center and results in stable coordination; Fe III /Fe II redox reaction is therefore an obstacle. By tuning the coordination surroundings of the metal ion , different memory types can be obtained.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Shuai Chen,Pin Liu,Kewen Su,Xuan Li,Zhen Qin,Wei Xu,Jun Chen,Chaorui Li,Jingfu Qiu
In this work, novel octahedral Cu 2 O-Au nanocomposites were synthesized and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of a DNAzyme for signal amplification . The octahedral Cu 2 O-Au nanocomposites have not only simultaneously served as signal amplifying molecules but have also been utilized as an ideal loading platform to immobilize a large number of electroactive substances and recognition probes. Gold nanoparticles (AuNPs) were grown directly on the surface of the octahedral Cu 2 O nanocrystals , and the Cu 2 O-Au nanocomposites obtained had the advantages of large surface areas and excellent biocompatibilities. The hemin/G-quadruplex, which was formed by intercalating hemin into the amino terminated thrombin binding aptamer (NH 2 -TBA), and the electroactive toluidine blue (Tb) were immobilized onto the Cu 2 O-Au nanocomposite surfaces through a stable Au-N bond. AuNPs, Cu 2 O and hemin/G-quadruplex co-catalyse the H 2 O 2 in the working buffer to promote the electron transfer of Tb as a multiple signal amplification strategy in order to improve the performance of the electrochemical aptasensor. Under optimal conditions, the designed aptasensor exhibited sensitive detection of TB from 100 fM to 20 nM with a lower detection limit of 23fM. This proposed aptasensor exhibited good sensitivity, high specificity and acceptable reproducibility and could be widely applied in bioassay analysis.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2016
·
IF 8.328
Xia Chen,Wangyang Lu,Tiefeng Xu,Nan Li,Dandan Qin,Zhexin Zhu,Gangqiang Wang,Wenxing Chen
In nature, metalloporphyrins, such as chlorophyll, cytochrome P450 and so forth, are key materials in maintaining the ecological cycles, especially the carbon cycle, and play an important role in both photosynthesis and the catalytic oxidation of organisms. Inspired by these factors, we skillfully combined photocatalysis and biomimetic catalysis using imidazole (IMD)-functionalized modification of g-C 3 N 4 and axial coordination with hemin. Compared with pure hemin, g-C 3 N 4 and a mixture of the two, our novel catalytic system (g-C 3 N 4 -IMD-hemin/H 2 O 2 ) showed high photocatalytic oxidation activity for the degradation of 4-chlorophenol (4-CP), and the stability of hemin was enhanced under solar irradiation. Furthermore, the effect of pH and the sustained photocatalytic oxidation stability of g-C 3 N 4 -IMD-hemin for degrading 4-CP were investigated. The results indicated that g-C 3 N 4 -IMD-hemin presents a high photocatalytic oxidation activity over a wide pH range and exhibits good recyclability. A series of designed experiments showed that superoxide radicals ( O 2 − ), high-valent iron (Fe(IV) = O) species, peroxy radicals ( OOH) and few hydroxyl radicals ( OH) were generated in the g-C 3 N 4 -IMD-hemin/H 2 O 2 system. This synergistic photocatalytic and biomimetic process offers new insight for the utilization of solar energy and offers a new perspective for the exploration of catalysts for environmental remediation.
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BIOSENSORS & BIOELECTRONICS
·
2016
·
IF 7.476
Fengping Liu,Jiaqian Tang,Jun Xu,Yun Shu,Qin Xu,Hongmei Wang,Xiaoya Hu
An amperometric sensor was firstly established for the detection of indole-3-acetic acid (IAA) at low potential based on the hemin/reduced graphene oxide (hemin/rGO) composite. The hemin/rGO nanocomposite was prepared by a simple and facile hydrothermal method without using any reducing agent. It exhibited peroxidase-like activity for the catalytic oxidation of IAA in the presence of oxygen. The consumption of oxygen has a linear relationship with the concentration of IAA in the range from 0.1 to 43 μM and from 43 to 183 μM. The detection limit was down to 0.074 μM. This sensor was unaffected by many interfering substances and stable over time. Such work broadened the application of hemin/rGO and provided a new method for IAA detection.
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TALANTA
·
2025
·
IF 6.1
Rong Tang,Chenglin Zhang,Baolian Liu,Yujie Kang,Ya Wang,Xiupei Yang
Recently, it has become valuable to develop strategies based on multi-mode sensors to detect analytes related to human health, food safety and environmental pollution. In this study, KL@PPIX-hemin composite prepared by immobilizing hemin and protoporphyrin IX (PPIX) on self-assembled peptide nanotubes (PNTs) through multiple non-covalent interactions were used for colorimetric/fluorescent dual-mode sensing of tannic acid (TA). PNTs as a carrier can provide the hydrophobic microenvironment for hemin and PPIX to protect them from dimerization, thus activating their respective peroxidase-mimicking activity and fluorescence emission. Further experiments show that the composite could catalyze H 2 O 2 to oxidize colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to generate blue ox-TMB, which could exactly quench the emission of PPIX by inner filter effect. The added TA can reduce ox-TMB to TMB and further turn on the fluorescence of system. A colorimetric/fluorescent dual-mode sensing system for TA was thus constructed and a low limit of detection (13.2 nM) was obtained. In addition, the analytical strategy has been successfully applied to accurate TA determination in actual tea samples. The method was also combined with smartphone to achieve visual detection of TA, which provides a broad prospect for portable and rapid tannic acid analysis.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xixiang Xie,Junxiang Zeng,Xianli Lan,Xiyu Liu,Jian He,Pan Wu,Yan Huang,Mengqi Chen,Meiyan Wu,Guiyin Li,Liang Shi,Yong Huang
As cholesterol is very intimately linked to the development of many types of cardiovascular diseases, clinical medicine must have a straightforward and precise method for determining total serum cholesterol (TC). Nowadays, enzymatic methods are routinely used in laboratories for the determination of TC, using cholesterol oxidase and esterase reagents for quantitative analysis on fully automated instruments. In this work, an electrochemical biosensor was developed for highly sensitive detection of cholesterol by modified modification of screen-printed carbon electrode (SPCE) and reduction of peroxidase-mimetic catalytic activity of reduced graphene oxide-hemin (RGO-hemin) nano-enzyme. The hydrolysis of cholesterol produced H 2 O 2 when it was subjected to the actions of cholesterol oxidase (CHOD), cholesterol esterase (CHER), and RGO-hemin. In the presence of H 2 O 2 , ferrocene-tyramine (Fc-Tyr) triggers catalytic deposition amplification effect on the SPCE surface, a great deal of electroactive ferrocene marker accumulates on the electrode surface, and Fc-Tyr is measured by an electrochemical workstation. The redox electrical signal detects the concentration of cholesterol in the sample. The biosensor had an operating range of 0.1∼5 mg/mL and a sensitivity of 24.43 μg/mL with acceptable specificity. The electrochemical cholesterol biosensor sensitively captured cholesterol signals in a complex body fluid environment and showed results consistent with clinical trials, with 96.63∼107.32 % recovery and 0.78∼5.28 % relative standard deviation (RSD). Therefore, there is a significant chance that the cholesterol biosensor by the institute will be used in clinical settings to detect serum cholesterol.
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TALANTA
·
2024
·
IF 5.6
Changjiang Li,Yuqiang Hu,Tianzi Shi,Kejun Dong,Tongbo Wu
The expression level of human apurinic/apyrimidinic endonuclease 1 (APE1) is closely associated with the onset of various diseases, establishing it as a crucial clinical biomarker and a target in anti-cancer efforts. This study accomplished colorimetric and visual detection of APE1 by harnessing its endonuclease activity through catalytic hairpin self-assembly (CHA) and G-quadruplex/hemin DNAzyme. Optimization of the freedom degrees of the G-rich sequence significantly improved the detection performance of the strategy by influencing DNAzyme formation. Additionally, we replaced the signal reporting system with a molecular beacon to develop a fluorescence detection strategy, which served as an extension of the signal amplification system for validation and signal readout. The fluorescent probe method achieved a detection limit of 3.37 × 10 −4 U/mL, while the colorimetric method yielded a detection limit of 6.5 × 10 −3 U/mL, with a linear range spanning from 0.01 to 0.25 U/mL. Subsequently, the colorimetric approach effectively assessed APE1 activity in biological samples and facilitated the screening of APE1 activity inhibitors. Furthermore, this CHA/G-quadruplex/hemin DNAzyme strategy was adapted for the colorimetric detection of adenosine, showcasing its broad applicability across various biomarkers. The developed colorimetric analytical strategy represents a pivotal biosensing platform for diagnosing and treating diseases.
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Analytical Methods
·
2017
·Vol. 10
·期 1
·84-90
·
IF 1.9
Xia Lin,Shu Zhu,Qiao Xia,Jiao Ma,Yingzi Fu
Herein, an ultrasensitive and stereo-selective electrochemiluminescent (ECL) biosensor based on ECL signal amplification of luminol by the synergetic catalysis of a hemin-functionalized composite and gold–platinum nanowires (Au-PtNWs) has been designed for the detection of D-alanine (D-Ala). In the sensor design, D-amino acid oxidase (DAAO) was used to generate the ECL co-reactant (H2O2) for luminol in situ. The reduced graphene oxide-hemin-cysteine (rGO-H-Cys) composite and Au-PtNWs acted not only as amplification labels to amplify signals via synergetic catalysis, but also as an ideal nanocarrier to accelerate electron transfer. A great difference in ECL intensities toward D-Ala and L-Ala was obtained, and an obviously higher intensity was seen for D-Ala. Under optimal conditions, the ECL intensity had a linear relationship with the logarithm of the D-Ala concentration in the range from 1.0 × 10−9 to 5.0 × 10−3 M with a detection limit of 3.3 × 10−10 M (S/N = 3). This study provides a new method for the determination of D-Ala in food with high sensitivity, excellent selectivity, and good stability and reproducibility.
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Frontiers in Chemistry
·
2025
·
IF 4.2
Ting Yuan,Jianbo Yuan,Jian Huang,Nana Li,Huan Cai,Yan Yang,Juan Li,Rui Chen,Xun Min
Introduction: The rapid and accurate identification of Mycobacterium tuberculosis (MTB) is essential for effective tuberculosis (TB) control. However, conventional diagnostic methods for MTB suffer from limitations such as low sensitivity, poor specificity, high cost, reliance on specialized instruments, and complex, time-consuming procedures. To address these challenges, there is an urgent need for a simple, rapid, and highly sensitive detection method that can be deployed in point-of-care settings.Methods: We developed a one-pot biosensing system combining recombinase polymerase amplification (RPA) and CRISPR/Cas12a-driven G4-hemin self-assembly for the colorimetric detection of MTB. Glycerol was employed as a phase-separation barrier to prevent interference between RPA amplification and CRISPR/Cas12a trans-cleavage. A single-stranded DNA (ssDNA) probe, designed to self-assemble with ssDNA-hemin into G4-hemin nanozymes upon CRISPR/Cas12a-mediated cleavage, served as the reaction substrate. The ssDNA-hemin further enhanced the catalytic activity of the generated G4-hemin DNAzyme. The entire assay was completed in a single step within 60 min without requiring complex instrumentation.Results and Discussion: Under optimized conditions, the biosensing system achieved ultrasensitive naked-eye detection of MTB with a limit of detection (LOD) of 10 copies/μL, comparable to traditional four-step fluorescent assays. Clinical validation using 104 patient samples demonstrated high concordance with standard diagnostic methods. This approach combines the advantages of recombinase polymerase amplification (RPA), CRISPR/Cas12a specificity, and G4-hemin DNAzyme-based colorimetric signal amplification, enabling simple, equipment-free visual detection. Given its speed, sensitivity, and ease of use, this biosensing system holds significant promise for point-of-care MTB nucleic acid testing in resource-limited settings.
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