1
|
Liu Y, Chen X, Liu X, Guan W, Lu C. Aggregation-induced emission-active micelles: synthesis, characterization, and applications. Chem Soc Rev 2023; 52:1456-1490. [PMID: 36734474 DOI: 10.1039/d2cs01021f] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Aggregation-induced emission (AIE)-active micelles are a type of fluorescent functional materials that exhibit enhanced emissions in the aggregated surfactant state. They have received significant interest due to their excellent fluorescence efficiency in the aggregated state, remarkable processability, and solubility. AIE-active micelles can be designed through the self-assembly of amphipathic AIE luminogens (AIEgens) and the encapsulation of non-emissive amphipathic molecules in AIEgens. Currently, a wide range of AIE-active micelles have been constructed, with a significant increase in research interest in this area. A series of advanced techniques has been used to characterize AIE-active micelles, such as cryogenic-electron microscopy (Cryo-EM) and confocal laser scanning microscopy (CLSM). This review provides an overview of the synthesis, characterization, and applications of AIE-active micelles, especially their applications in cell and in vivo imaging, biological and organic compound sensors, anticancer drugs, gene delivery, chemotherapy, photodynamic therapy, and photocatalytic reactions, with a focus on the most recent developments. Based on the synergistic effect of micelles and AIE, it is anticipated that this review will guide the development of innovative and fascinating AIE-active micelle materials with exciting architectures and functions in the future.
Collapse
Affiliation(s)
- Yuhao Liu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
| | - Xueqian Chen
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
| | - Xiaoting Liu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
| | - Weijiang Guan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chao Lu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China. .,State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| |
Collapse
|
2
|
Abrahamse H, Hamblin MR, George S. Structure and functions of Aggregation-Induced Emission-Photosensitizers in anticancer and antimicrobial theranostics. Front Chem 2022; 10:984268. [PMID: 36110134 PMCID: PMC9468771 DOI: 10.3389/fchem.2022.984268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
Photosensitizers with Aggregation-Induced Emission (AIE) can allow the efficient light-mediated generation of Reactive Oxygen Species (ROS) based on their complex molecular structure, while interacting with living cells. They achieve better tissue targeting and allow penetration of different wavelengths of Ultraviolet-Visible-Infrared irradiation. Not surprisingly, they are useful for fluorescence image-guided Photodynamic Therapy (PDT) against cancers of diverse origin. AIE-photosensitizers can also function as broad spectrum antimicrobials, capable of destroying the outer wall of microbes such as bacteria or fungi without the issues of drug resistance, and can also bind to viruses and deactivate them. Often, they exhibit poor solubility and cellular toxicity, which compromise their theranostic efficacy. This could be circumvented by using suitable nanomaterials for improved biological compatibility and cellular targeting. Such dual-function AIE-photosensitizers nanoparticles show unparalleled precision for image-guided detection of tumors as well as generation of ROS for targeted PDT in living systems, even while using low power visible light. In short, the development of AIE-photosensitizer nanoparticles could be a better solution for light-mediated destruction of unwanted eukaryotic cells and selective elimination of prokaryotic pathogens, although, there is a dearth of pre-clinical and clinical data in the literature.
Collapse
Affiliation(s)
- Heidi Abrahamse
- Laser Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - Michael R. Hamblin
- Laser Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - Sajan George
- Laser Research Centre, University of Johannesburg, Doornfontein, South Africa
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, TN, India
- *Correspondence: Sajan George, ,
| |
Collapse
|
3
|
Wang B, Li C, Yang L, Zhang C, Liu LJ, Zhu S, Chen Y, Wang Y. Tetraphenylethene decorated with disulfide-functionalized hyperbranched poly(amido amine)s as metal/organic solvent-free turn-on AIE probes for biothiol determination. J Mater Chem B 2019. [DOI: 10.1039/c9tb00214f] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel hyperbranched poly(amido amine)s AIE probes were developed for organic solvent-free biothiol sensing.
Collapse
Affiliation(s)
- Bin Wang
- Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling, School of Science, Tianjin Chengjian University
- Tianjin 300384
- P. R. China
| | - Cheng Li
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University
- Tianjin 300354
- P. R. China
| | - Lijun Yang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College
- Tianjin 300192
- P. R. China
| | - Congrou Zhang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College
- Tianjin 300192
- P. R. China
| | - Li-Juan Liu
- Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling, School of Science, Tianjin Chengjian University
- Tianjin 300384
- P. R. China
| | - Sen Zhu
- Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling, School of Science, Tianjin Chengjian University
- Tianjin 300384
- P. R. China
| | - Yu Chen
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University
- Tianjin 300354
- P. R. China
| | - Yong Wang
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University
- Tianjin 300354
- P. R. China
| |
Collapse
|
4
|
Dong J, Liu M, Jiang R, Huang H, Wan Q, Wen Y, Tian J, Dai Y, Zhang X, Wei Y. Synthesis and biological imaging of cross-linked fluorescent polymeric nanoparticles with aggregation-induced emission characteristics based on the combination of RAFT polymerization and the Biginelli reaction. J Colloid Interface Sci 2018; 528:192-199. [PMID: 29857250 DOI: 10.1016/j.jcis.2018.05.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 02/07/2023]
Abstract
Fluorescent probes have long been regarded as tools for imaging living organisms with advantages such as high sensitivity, good designability and multifunctional potential. Many fluorescent probes, especially the probes based on aggregation-induced emission (AIE) dyes, have received increasing attention since the AIE phenomenon was discovered. These AIE dye-based fluorescent probes could elegantly overcome the notorious quenching effect caused by aggregation of conventional organic dyes. However, it is still difficult to directly apply these AIE-active dyes for biomedical applications owing to their hydrophobic nature. Therefore, the development of novel and facile strategies to endow them with water dispersibility is of critical importance. In this work, we exploit an efficient and simple strategy to fabricate an AIE dye-based fluorescent copolymer through the combination of reversible addition-fragmentation chain transfer and the Biginelli reaction. Moreover, the copolymer can self-assemble to fluorescent polymeric nanoparticles (FPNs) in water solution. Hydrophilic poly(PEGMA-co-AEMA) was reacted with the AIE-active dye 4',4‴-(1,2-diphenylethene-1,2-diyl)bis([1,1'-biphenyl]-4-carbaldehyde (CHO-TPE-CHO) to form amphiphilic luminescent polymers using urea as the connection bridge. The successful synthesis of the final products (poly(PEGMA-co-AEMA-TPE) FPNs) was confirmed by various instruments. Furthermore, Transmission electron microscopy (TEM) images manifest that poly(PEGMA-co-AEMA-TPE) copolymers will self-assemble into spherical nanoparticles in aqueous environments with sizes between 100 nm and 200 nm. The cell uptake and bioimaging experiment confirm that poly(PEGMA-co-AEMA-TPE) FPNs have excellent biocompatibility and emit strong green fluorescence in a cellular environment. Thus, poly(PEGMA-co-AEMA-TPE) FPNs are excellent candidates for biomedical applications.
Collapse
Affiliation(s)
- Jiande Dong
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Meiying Liu
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Ruming Jiang
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Hongye Huang
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Qing Wan
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Yuanqing Wen
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Jianwen Tian
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Yanfeng Dai
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China
| | - Xiaoyong Zhang
- Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China.
| | - Yen Wei
- Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing 100084, China; Department of Chemistry and Center for Nanotechnology and Institute of Biomedical Technology, Chung-Yuan Christian University, Chung-Li 32023, Taiwan
| |
Collapse
|
5
|
Quinn JF, Whittaker MR, Davis TP. Glutathione responsive polymers and their application in drug delivery systems. Polym Chem 2017. [DOI: 10.1039/c6py01365a] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Materials which respond to biological cues are the subject of intense research interest due to their possible application in smart drug delivery vehicles.
Collapse
Affiliation(s)
- John F. Quinn
- ARC Centre of Excellence in Convergent Bio-Nano Science & Technology
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Melbourne
- Australia
| | - Michael R. Whittaker
- ARC Centre of Excellence in Convergent Bio-Nano Science & Technology
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Melbourne
- Australia
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science & Technology
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Melbourne
- Australia
| |
Collapse
|
6
|
Cheng W, Wu D, Liu Y. Michael Addition Polymerization of Trifunctional Amine and Acrylic Monomer: A Versatile Platform for Development of Biomaterials. Biomacromolecules 2016; 17:3115-3126. [DOI: 10.1021/acs.biomac.6b01043] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Weiren Cheng
- Institute
of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way Innovis #08-03, Singapore 138634
| | - Decheng Wu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics & Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Ye Liu
- Institute
of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way Innovis #08-03, Singapore 138634
| |
Collapse
|
7
|
Redoxable heteronanocrystals functioning magnetic relaxation switch for activatable T1 and T2 dual-mode magnetic resonance imaging. Biomaterials 2016; 101:121-30. [PMID: 27281684 DOI: 10.1016/j.biomaterials.2016.05.054] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 11/22/2022]
Abstract
T1/T2 dual-mode magnetic resonance (MR) contrast agents (DMCAs) have gained much attention because of their ability to improve accuracy by providing two pieces of complementary information with one instrument. However, most of these agents are "always ON" systems that emit MR contrast regardless of their interaction with target cells or biomarkers, which may result in poor target-to-background ratios. Herein, we introduce a rationally designed magnetic relaxation switch (MGRS) for an activatable T1/T2 dual MR imaging system. Redox-responsive heteronanocrystals, consisting of a superparamagnetic Fe3O4 core and a paramagnetic Mn3O4 shell, are synthesized through seed-mediated growth and subsequently surface-modified with polysorbate 80. The Mn3O4 shell acts as both a protector of Fe3O4 in aqueous environments to attenuate T2 relaxation and as a redoxable switch that can be activated in intracellular reducing environments by glutathione. This simultaneously generates large amounts of magnetically decoupled Mn(2+) ions and allows Fe3O4 to interact with the water protons. This smart nanoplatform shows an appropriate hydrodynamic size for the EPR effect (10-100 nm) and demonstrates biocompatibility. Efficient transitions of OFF/ON dual contrast effects are observed by in vitro imaging and MR relaxivity measurements. The ability to use these materials as DMCAs is demonstrated via effective passive tumor targeting for T1- and T2-weighted MR imaging in tumor-bearing mice.
Collapse
|
8
|
Mei J, Leung NLC, Kwok RTK, Lam JWY, Tang BZ. Aggregation-Induced Emission: Together We Shine, United We Soar! Chem Rev 2015; 115:11718-940. [DOI: 10.1021/acs.chemrev.5b00263] [Citation(s) in RCA: 5139] [Impact Index Per Article: 571.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ju Mei
- HKUST-Shenzhen Research Institute, Hi-Tech
Park, Nanshan, Shenzhen 518057, China
- Department of Chemistry,
HKUST Jockey Club Institute for Advanced Study, Institute of Molecular
Functional Materials, Division of Biomedical Engineering, State Key
Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Nelson L. C. Leung
- HKUST-Shenzhen Research Institute, Hi-Tech
Park, Nanshan, Shenzhen 518057, China
- Department of Chemistry,
HKUST Jockey Club Institute for Advanced Study, Institute of Molecular
Functional Materials, Division of Biomedical Engineering, State Key
Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ryan T. K. Kwok
- HKUST-Shenzhen Research Institute, Hi-Tech
Park, Nanshan, Shenzhen 518057, China
- Department of Chemistry,
HKUST Jockey Club Institute for Advanced Study, Institute of Molecular
Functional Materials, Division of Biomedical Engineering, State Key
Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jacky W. Y. Lam
- HKUST-Shenzhen Research Institute, Hi-Tech
Park, Nanshan, Shenzhen 518057, China
- Department of Chemistry,
HKUST Jockey Club Institute for Advanced Study, Institute of Molecular
Functional Materials, Division of Biomedical Engineering, State Key
Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ben Zhong Tang
- HKUST-Shenzhen Research Institute, Hi-Tech
Park, Nanshan, Shenzhen 518057, China
- Department of Chemistry,
HKUST Jockey Club Institute for Advanced Study, Institute of Molecular
Functional Materials, Division of Biomedical Engineering, State Key
Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- Guangdong
Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State
Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| |
Collapse
|
9
|
Cheng W, Wang G, Kumar JN, Liu Y. Surfactant-Free Emulsion-Based Preparation of Redox-Responsive Nanogels. Macromol Rapid Commun 2015; 36:2102-6. [PMID: 26379215 DOI: 10.1002/marc.201500421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/19/2015] [Indexed: 01/28/2023]
Abstract
A surfactant-free emulsion-based approach is developed for preparation of nanogels. A water-in-oil emulsion is generated feasibly from a mixture of water and a solution of disulfide-containing hyperbranched PEGylated poly(amido amine)s, poly(BAC2-AMPD1)-PEG, in chloroform. The water droplets in the emulsion are stabilized and filled with poly(BAC2-AMPD1)-PEG, and the crosslinked poly(amido amine)s nanogels are formed via the intermolecular disulfide exchange reaction. FITC-dextran is loaded within the nanogels by dissolving the compound in water before emulsification. Transmission electron microscopy and dynamic light scattering are applied to characterize the emulsion and the nanogels. The effects of the homogenization rate and the ratio of water/polymer are investigated. Redox-induced degradation and FITC-dextran release profile of the nanogels are monitored, and the results show efficient loading and redox-responsive release of FITC-dextran. This is a promising approach for the preparation of nanogels for drug delivery, especially for neutral charged carbohydrate-based drugs.
Collapse
Affiliation(s)
- Weiren Cheng
- Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore, 117602, Singapore
| | - Guan Wang
- Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore, 117602, Singapore
| | - Jatin Nitin Kumar
- Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore, 117602, Singapore
| | - Ye Liu
- Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore, 117602, Singapore
| |
Collapse
|
10
|
Huang L, Yan C, Cui D, Yan Y, Liu X, Lu X, Tan X, Lu X, Xu J, Xu Y, Liu R. Organic Radical Contrast Agents Based on Polyacetylenes Containing 2,2,6,6-Tetramethylpiperidine 1-Oxyl (TEMPO): Targeted Magnetic Resonance (MR)/Optical Bimodal Imaging of Folate Receptor Expressing HeLa Tumors in Vitro and in Vivoa. Macromol Biosci 2015; 15:788-98. [PMID: 25677802 DOI: 10.1002/mabi.201400403] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 01/23/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Lixia Huang
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
- Department of Radiology; Guangdong Provincial Traditional Chinese Medical Hospital; Guangzhou 510120 China
| | - Chenggong Yan
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Danting Cui
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Yichen Yan
- School of Pharmaceutical Sciences; Southern Medical University; Guangzhou 510515 China
| | - Xiang Liu
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Xinwei Lu
- School of Pharmaceutical Sciences; Southern Medical University; Guangzhou 510515 China
| | - Xiangliang Tan
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Xiaodan Lu
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Jun Xu
- Department of Hematology, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Yikai Xu
- Department of Medical Imaging Center, Nanfang Hospital; Southern Medical University; Guangzhou 510515 China
| | - Ruiyuan Liu
- School of Pharmaceutical Sciences; Southern Medical University; Guangzhou 510515 China
| |
Collapse
|
11
|
Cheng W, Kumar JN, Zhang Y, Liu Y. pH- and redox-responsive self-assembly of amphiphilic hyperbranched poly(amido amine)s for controlled doxorubicin delivery. Biomater Sci 2015. [PMID: 26222420 DOI: 10.1039/c4bm00410h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vinyl-terminated hyperbranched poly(amido amine)s is obtained by Michael addition polymerization of 4-(aminomethyl)piperidine (AMPD) with a double molar N,N-cystaminebis(acrylamide) (BAC). Then an amphiphilic hyperbranched poly(BAC2-AMPD1)-PEG is produced via converting the vinyl groups to amines followed by PEGylation. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and (1)H nuclear magnetic resonance (NMR) results indicate that the micelles can be obtained via self-assembly of hyperbranched poly(BAC2-AMPD1)-PEG. Further an anti-cancer drug, doxorubicin (DOX), can be loaded into the micelles. pH- and redox-response of the micelles of hyperbranched poly(BAC2-AMPD1)-PEG without and with DOX are investigated. The results of confocal microscopy and flow cytometry reflect that FITC tagged or DOX loaded micelles of hyperbranched poly(BAC2-AMPD1)-PEG can enter HepG2 and MCF-7 cells, and DOX can be observed in the nucleus of the cells. The cytotoxicity of the micelles without and with DOX is evaluated in HepG2 and MCF-7 cells, and the efficacy to kill the cancer cells is discussed in comparison with free DOX.
Collapse
Affiliation(s)
- Weiren Cheng
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore.
| | | | | | | |
Collapse
|