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Liu X, Li Y, Yang Q, Cai H, Wang L, Zhao X. Improving the antioxidant activity of natural antioxidant honokiol by introducing the amino group. J Mol Model 2021; 27:350. [PMID: 34757484 DOI: 10.1007/s00894-021-04977-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/03/2021] [Indexed: 12/18/2022]
Abstract
Exploring and synthesizing the compounds with stronger antioxidant activity have always been the goal of researchers. Herein, the substitution effects of the amino (NH2-) group with the excellent electron-donating ability in different positions on the antioxidant activity of Honokiol (Hon) were systematically explored by using the quantum chemistry calculation based on the density functional theory method. The three possible antioxidant mechanisms of Hon and its four NH2-substituted derivatives (Hon1-Hon4), containing the hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET), were explored in depth considering the gas and solvent phases. In addition, the frontier molecular orbital energies, natural bond orbital (NBO) charge population, and global descriptive parameters were used to study their antioxidant activity. The results indicate that compared with the original molecule Hon, the NH2 substituents would have the stronger antioxidant activity. Moreover, the radical scavenging process of Hon and its derivatives has a disposition to the HAT and SPLET mechanisms in the gas and solvent phases, respectively. Meaningfully, owing to the lowest bond dissociation enthalpy and proton affinity values, Hon4 would show the most prominent antioxidant activity by comparison with the other compounds. In conclusion, this work will provide the purposeful reference for designing and synthesizing the antioxidants with more outstanding performance.
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Affiliation(s)
- Xiaohu Liu
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China.,Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, China
| | - Yuanzuo Li
- College of Science, Northeast Forestry University, Harbin, 150040, China
| | - Qilei Yang
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China.,Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, China
| | - Hongda Cai
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China.,Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, China
| | - Lingling Wang
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China. .,Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, China.
| | - Xiuhua Zhao
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China. .,Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, China.
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Perumal Veeramalai C, Kollu P, Lin G, Zhang X, Li C. Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics. NANOTECHNOLOGY 2021; 32:315204. [PMID: 33857936 DOI: 10.1088/1361-6528/abf87a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs concurrently to realize the high-performance optoelectronic devices. In the current article, we have demonstrated the high-performance photodetector based on graphene: CdSe QDs/CdS nanorod heterostructures. The resulting heterojunction photodetector with device configuration ITO/graphene: CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW-1and specific detectivity of 6.85 × 1012Jones under 530 nm light illumination. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the study of the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector is carried out. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated led to the enhancement of photocurrent density. In addition to that, the graphene: CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilizing advantageous features of graphene in optoelectronic devices.
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Affiliation(s)
| | - Pratap Kollu
- CASEST, School of Physics, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
| | - Guochen Lin
- School of Sciences, Minzu University of China, Beijing 100081, People's Republic of China
| | - Xiaoming Zhang
- School of Sciences, Minzu University of China, Beijing 100081, People's Republic of China
| | - Chuanbo Li
- School of Sciences, Minzu University of China, Beijing 100081, People's Republic of China
- Optoelectronics Research Center, Minzu University of China, Beijing 100081, People's Republic of China
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Graphene/PbS quantum dot hybrid structure for application in near-infrared photodetectors. Sci Rep 2020; 10:12475. [PMID: 32719367 PMCID: PMC7385648 DOI: 10.1038/s41598-020-69302-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 06/22/2020] [Indexed: 01/25/2023] Open
Abstract
A graphene-PbS quantum dot (QD) composite for application in high-performance near-infrared (NIR) photodetectors (PDs) is proposed in this study. A single-layer graphene flake and oleic acid-capped PbS QD composite is fabricated through the conventional sonication process, in hexane solution. Field emission scanning electron microscopy images of the graphene-PbS QD composite dispersed on a glass substrate confirm that the composite contains both aggregated graphene flakes and single-layer graphene with wrinkles; Transmission electron microscopy images reveal close packing with uniform size. The increased absorbance and quenched photoluminescence intensity of the graphene-PbS QD composite supports enhanced photoinduced charge transfer between graphene and the PbS QDs. Moreover, the specific Raman mode of the PbS QDs, embedded in the spectrum, is enhanced by combination with graphene, which can be interpreted by SERS as relevant to the photoinduced charge transfer between the Pbs QDs and graphene. For device application, a PD structure comprised by graphene-PbS QDs is fabricated. The photocurrent of the PD is measured using a conventional probe station with a 980-nm NIR laser diode. In the fabricated PD comprising graphene-PbS QDs, five-times higher photocurrent, 22% faster rise time, and 47% faster decay time are observed, compared to that comprising PbS QDs alone. This establishes the potential of the graphene-PbS QD composite for application in ultrathin, flexible, high-performance NIR PDs.
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Screening of functional monomers and solvents for the molecular imprinting of paclitaxel separation: a theoretical study. J Mol Model 2020; 26:26. [PMID: 31927620 DOI: 10.1007/s00894-019-4277-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/09/2019] [Indexed: 12/14/2022]
Abstract
The interactions between the template molecule paclitaxel (PTX) and seven functional monomers containing methacrylic acid (MA), acrolein (AC), 4-vinylbenzoic acid (4VA), acrylonitrile (AN), 2-vinylpyridine (2VP), 2,6-bisacrylamide pyridine (BAP) and methyl methacrylate (MM) were systematically investigated adopting the density functional theory (DFT) method. Moreover, the different binding sites on PTX and solvents embracing chloroform, acetone, ethanol, methanol, and acetonitrile were considered. The calculated solvent energies (ΔEsolvent) and template-monomer binding energies (ΔEb) suggest that the chloroform is the most suitable solvent for the molecular imprinting reaction of PTX among the studied five solvents. Furthermore, from the obtained ΔEb, we can find that the monomer 4VA combining with PTX in the form of the specific intermolecular hydrogen bonds would present the most stable structure among the investigated monomers. These results can provide valuable theoretical guidance for the efficient extraction of PTX by the molecular imprinting technique in experiments. Graphical abstracts.
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Ghafary Z, Hallaj R, Salimi A, Akhtari K. A Novel Immunosensing Method Based on the Capture and Enzymatic Release of Sandwich-Type Covalently Conjugated Thionine-Gold Nanoparticles as a New Fluorescence Label Used for Ultrasensitive Detection of Hepatitis B Virus Surface Antigen. ACS OMEGA 2019; 4:15323-15336. [PMID: 31572831 PMCID: PMC6761744 DOI: 10.1021/acsomega.9b00713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/22/2019] [Indexed: 05/05/2023]
Abstract
A novel ultrasensitive and simple amplified immunosensing strategy is designed based on a surface-enhanced fluorescence (SEF) nanohybrid made from covalently conjugated thionine-gold nanoparticles (GNP-Th), as a novel amplified fluorescence label, and magnetic nanoparticles (MNPs), as a biological carrier, used for hepatitis B virus surface antigen (HBsAg) detection. This immunosensing strategy operates on the basis of the capture and then release of the amplified fluorescence label. Capturing of the antiHBs-antibody (Ab)-modified GNP-thionine hybrid (GNP-Th-Ab) is carried out through the formation of a two-dimensional (sandwich) probe between this amplified label and antiHBs-antibody-modified magnetic nanoparticles (MNP-Ab), in the presence of a target antigen and using an external magnetic force. Afterward, releasing of the captured fluorescence label is performed using a protease enzyme (pepsin) by a digestion mechanism of grafted antibodies on the GNP-thionine hybrid. As a result of antibody digestion, the amplified fluorescent hybrids (labels) are released into the solution. To understand the mechanism of enhanced fluorescence, the nature of the interaction between thionine and gold nanoparticles is studied using the B3LYP density functional method. In such a methodology, several new mechanisms and structures are used simultaneously, including a SEF-based metal nanoparticle-organic dye hybrid, dual signal amplification in a two-dimensional probe between the GNP-thionine hybrid and MNPs, and a novel releasing method using protease enzymes. These factors improve the sensitivity and speed, along with the simplicity of the procedure. Under optimal conditions, the fluorescence signal increases with the increment of HBs antigen concentration in the linear dynamic range of 4.6 × 10-9 to 0.012 ng/mL with a detection limit (LOD) of 4.6 × 10-9 ng/mL. The proposed immunosensor has great potential in developing ultrasensitive and rapid diagnostic platforms.
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Affiliation(s)
- Zhaleh Ghafary
- Department of Chemistry, Nanotechnology Research Center, and Department of
Physics, University of Kurdistan, P.O. Box 416, Sanandaj 6617715175, Iran
| | - Rahman Hallaj
- Department of Chemistry, Nanotechnology Research Center, and Department of
Physics, University of Kurdistan, P.O. Box 416, Sanandaj 6617715175, Iran
| | - Abdollah Salimi
- Department of Chemistry, Nanotechnology Research Center, and Department of
Physics, University of Kurdistan, P.O. Box 416, Sanandaj 6617715175, Iran
| | - Keivan Akhtari
- Department of Chemistry, Nanotechnology Research Center, and Department of
Physics, University of Kurdistan, P.O. Box 416, Sanandaj 6617715175, Iran
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Chen JS, Li M, Cotlet M. Nanoscale Photoinduced Charge Transfer with Individual Quantum Dots: Tunability through Synthesis, Interface Design, and Interaction with Charge Traps. ACS OMEGA 2019; 4:9102-9112. [PMID: 31459998 PMCID: PMC6648770 DOI: 10.1021/acsomega.9b00803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/03/2019] [Indexed: 05/29/2023]
Abstract
Semiconducting colloidal quantum dots (QDs) provide an excellent platform for nanoscale charge-transfer studies. Because of their size-dependent optoelectronic properties, which can be tuned via chemical synthesis and of their versatility in surface ligand exchange, QDs can be coupled with various types of acceptors to create hybrids with controlled type (electron or hole), direction, and rate of charge flow, depending on the foreseen application, either solar harvesting, light emitting, or biosensing. This perspective highlights several examples of QD-based hybrids with controllable (tunable) rate of charge transfer obtained by various approaches, including by changing the QD core size and shell thickness by colloidal synthesis, by the insertion of molecular linkers or dielectric spacers between donor and acceptor components. We also show that subjecting QDs to external factors such as electric fields and alternate optical excitation energy is another approach to bias the internal charge transfer between charges photogenerated in the QD core and QD's surface charge traps. The perspective also provides the reader with various examples of how single nanoparticle spectroscopic studies can help in understanding and quantifying nanoscale charge transfer with QDs.
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Affiliation(s)
- Jia-Shiang Chen
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
- Department
of Materials Science and Chemical Engineering, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Mingxing Li
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - Mircea Cotlet
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
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