槲皮素是植物中發現的天然類黃酮分子，具有抗氧化和抗發炎之特性，是促進傷口癒合的潛在藥物。銅是一種常見的金屬或金屬氧化物奈米材料，與細菌作用時可造成脂質、蛋白質和核酸的氧化損傷導致細菌死亡。然而，銅在抑菌過程中產生的大量活性氧會引發嚴重發炎反應，使得傷口難以癒合。因此，通過槲皮素的抗氧化與抗發炎特性，有機會緩解銅在治療感染性傷口過程中的產生副作用，加速傷口癒合。在這項研究中，我們使用簡單的一步法製備銅離子配位聚槲皮素 (Copper ion-coordination polyQuercetin, Cu-pQu) 複合材料，具有纖維狀的網絡結構，並含有銅奈米顆粒於其間。通過pQu與細菌膜間的作用，以及銅離子能造成細菌氧化壓力升高的行為，該複合材料可以有效抑制在磷酸鹽緩衝生理鹽水中的革蘭氏陰性細菌 (大腸桿菌、綠膿桿菌、肺炎鏈球菌)、革蘭氏陽性細菌 (金黃色葡萄球菌) 和耐甲氧西林金黃色葡萄球菌 (MRSA) 生長。其最小抑菌濃度 (MIC 90) 為5 µg mL-1，為氧化銅奈米粒子和pQu的0.1倍。結果表明，pQu能與銅表現出加成作用，可有效降低Cu抑菌的最低濃度。此材料在濃度為100 µg mL-1 (20倍MIC 90) 時，對人類角質形成細胞 (HaCaT) 未具有毒性且亦無溶血現象發生，結果證明此材料具有良好的生物相容性。另一方面，此複合材料保留了pQu的抗氧化特性，能有效降低外源性H2O2誘發巨噬細胞的發炎反應。與氧化銅奈米粒子和3M傷口護理敷料相比，Cu-pQu在MRSA感染的糖尿病鼠傷口的治療上，具有抑制細菌生長和傷口發炎的作用並能加速傷口癒合的閉合率，於治療慢性感染性傷口治療具有優秀的潛力。

Quercetin is a natural flavonoid molecule found in plants. The anti-oxidant and anti-inflammatory properties make it a potential drug candidate for facilitated wound healing. Copper is a common metal or metal oxide bactericidal nanoparticle, which can interact with bacteria and lead to effective oxidative damages to lipid, proteins and nucleic acids. However, high amount of reactive oxygen species production induced by copper may cause severe inflammation, which makes the wound difficult to heal. The potential anti-inflammatory properties of quercetin may therefore neutralize the adverse effects of copper to improve the healing process for the treatment of infected chronic wound. In this study, we reported a simple one-step method for the preparation of copper ion-coordination polyQuercetin (Cu-pQu) composites, consisting a fibrous network of Cu-pQu decorated with copper-based nanoparticles. Through the interaction between pQu and bacterial membrane, as well as the ability of copper ions to promote oxidative-damages, this composite can effectively inhibit the growth of Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Streptococcus pneumoniae), Gram-positive bacteria (Staphylococcus aureus) and methicillin-resistant Staphylococcus aureus (MRSA) in phosphate buffered saline. The 90% minimum inhibitory concentration (MIC 90) of Cu-pQu is 5 µg mL-1, which is about 0.1 times lower than copper oxide nanoparticles (CuO NPs) and pQu, respectively. This result suggests that pQu exhibits an additive effect with Cu, leading to an efficient eradication of bacteria with reduced Cu level to minimize the cytotoxicity toward Human Keratinocyte HaCaT cells. Cu-pQu also demonstrates a good degree of biocompatibility, showing negligible levels of hemolysis at a concentration of 100 µg mL-1 (20 times the MIC 90). Moreover, the pQu in the resulting composite retains its DPPH scavenging activity, leading to an effective inhibition of the inflammatory response induced by exogenous H2O2. When applied as a topical medication for the treatment of MRSA-infected wounds in diabetic mice, Cu-pQu not only shows potent a bactericidal activity in vivo but also an accelerated wound closure rate as compared with CuO NPs and 3M wound care dressings. Collectively, the antibacterial, anti-antioxidant and inflammatory properties of the devolved Cu-pQu make it a promising paradigm for the treatment of chronic wound infections in clinics.

1. Velnar, T.; Bailey, T.; Smrkolj, V. The Wound Healing Process: An Overview of the Cellular and Molecular Mechanisms. J. Int. Med. Res. 2009, 37, 1528–1542.
2. Krzyszczyk, P.; Schloss, R.; Palmer, A.; Berthiaume, F. The Role of Macrophages in Acute and Chronic Wound Healing and Interventions to Promote Pro-wound Healing Phenotypes. Front. Physiol. 2018, 9, 419.
3. Qing, C. The Molecular Biology in Wound Healing & Non-Healing Wound. Chin. J. Traumatol. 2017, 20, 189−193.
4. Leaper, D.; Assadian, O.; Edmiston, C. E. Approach to Chronic Wound Infections. Br. J. Dermatol. 2015, 173, pp351‒358.
5. Lindley, L. E.; Stojadinovic, O.; Pastar, I.; Tomic-Canic, M. Biology and Biomarkers for Wound Healing. Plast. Reconstr. Surg. 2016, 138, 18S–28S.
6. Liao, S.; Zhang, Y.; Pan, X.; Zhu, F.; Jiang, C.; Liu, Q.; Cheng, Z.; Dai, G.; Wu, G.; Wang, L.; Chen, L. Antibacterial Activity and Mechanism of Silver Nanoparticles Against Multidrug-Resistant Pseudomonas Aeruginosa. Int. J. Nanomed. 2019, 14, 1469‒1487.
7. Qing, Y.; Cheng, L.; Li, R.; Liu, G.; Zhang, Y.; Tang, X.; Wang, J.; Liu, H.; Qin, Y. Potential Antibacterial Mechanism of Silver Nanoparticles and the Optimization of Orthopedic Implants by Advanced Modification Technologies. Int. J. Nanomed. 2018, 13, 3311‒3327.
8. Yan, X.; He, B.; Liu, L.; Qu, G.; Shi, J.; Hu, L.; Jiang, G. Antibacterial Mechanism of Silver Nanoparticles in Pseudomonas Aeruginosa: Proteomics Approach. Metallomics 2018, 10, 557‒564.
9. Din, M. I.; Arshad, F.; Hussain, Z.; Mukhtar M. Green Adeptness in the Synthesis and Stabilization of Copper Nanoparticles: Catalytic, Antibacterial, Cytotoxicity, and Antioxidant Activities. Nanoscale Res. Lett. 2017, 12, 638.
10. Chatterjee, A. K.; Chakraborty, R.; Basu, T. Mechanism of Antibacterial Activity of Copper Nanoparticles. Nanotechnology 2014, 25, 135101.
11. Borkow, G. Using Copper to Improve the Well-Being of the Skin. Curr. Chem. Biol. 2014, 8, 89‒102.
12. Andersen, E. J.; Ali, S.; Byamukama, E.; Yen, Y.; Nepal, M. P. Disease Resistance Mechanisms in Plants. Genes 2018, 9, 339.
13. Cos, P.; Calomme, M.; Pieters, L.; Vlietinck, A. J.; Vanden, B. D. Structure-Activity Relations of Flavonoids as Antioxidant And Pro-Oxidant Compounds. Stud. Nat. Prod. Chem. 2000, 22, 307−341.
14. Beecher, G. R. Overview of Dietary Flavonoids: Nomenclature, Occurrence and Intake. J. Nutr. 2003, 133, 3248S–3254S.
15. Salehi, B.; Venditti, A.; Sharifi-Rad, M.; Kręgiel, D.; Sharifi-Rad, J.; Durazzo, A.; Lucarini, M.; Santini, A.; Souto, E. B.; Novellino, E.; Antolak, H.; Azzini, E.; Setzer, W. N.; Martins, N. The Therapeutic Potential of Apigenin. Int. J. Mol. Sci. 2019, 20, 1305.
16. Wang, T.; Li, Q.; Bi, K. Bioactive Flavonoids in Medicinal Plants: Structure, Activity and Biological Fate. Asian J. Pharm. Sci. 2018, 13, 12‒23.
17. Serafini, M.; Peluso, I.; Raguzzini, A. Session 1: Antioxidants and the Immune System Flavonoids as Anti-Inflammatory Agents. Proc. Nutr. Soc. 2010, 69, 273−278.
18. Yin, G.; Wang, Z.; Wang, Z.; Wang, X. Topical Application of Quercetin Improves Wound Healing in Pressure Ulcer Lesions. Exp. Dermatol. 2018, 27, 779‒786.
19. Wang, H.; Nair, M. G.; Strasburg, G. M.; Boorerr, A. M.; Gray, I.; Dewitt, D. L. Cyclooxygenase Active Bioflavonoids from Balaton™ Tart Cherry and Their Structure Activity Relationships. Phytomedicine 2000, 7, pp. 15‒19.
20. Ribeiro, D.; Freitas, M.; Tomé, S. M.; Silva, A. M. S.; Laufer, S.; Lima, J. L. F. C.; Fernandes, E. Flavonoids Inhibit COX-1 and COX-2 Enzymes and Cytokine/Chemokine Production in Human Whole Blood. Inflammation 2015, 38, 858‒870.
21. Rotelli, A. E.; Guardia, T.; Juárez, A. O.; de la Rocha, N. E.; Pelzer, L. E. Comparative Study of flavonoids in Experimental Models of Inflammation. Pharmacol. Res. 2003, 48, 601‒606.
22. Liang, Y.-C.; Huang, Y.-T.; Tsai, S.-H.; Lin-Shiau, S.-Y.; Chen, C.-F.; Lin, J.-K. Suppression of Inducible Cyclooxygenase and Inducible Nitric Oxide Synthase by Apigenin and Related flavonoids in Mouse Macrophages. Carcinogenesis 1999, 20, pp. 1945‒1952.
23. Antunes-Ricardo, M.; Gutiérrez-Uribe, J. A.; Martínez-Vitela, C.; Serna-Saldívar, S. O. Topical Anti-Inflammatory Effects of Isorhamnetin Glycosides Isolated from Opuntia ficus-indica. Biomed Res. Int. 2015, 2015, Article ID 847320.
24. Doersch, K. M.; Newell-Rogers, M. K. The Impact of Quercetin on Wound Healing Relates to Changes in αV And β1 Integrin Expression. Exp. Biol. Med. 2017, 0, 1‒8.
25. Ahamed, M.; Alhadlaq, H. A.; Khan, M. A.; Karuppiah, P.; Al-Dhabi, N. A. Synthesis, Characterization, and Antimicrobial Activity of Copper Oxide Nanoparticles. J. Nanomater. 2014, 2014, Article ID 637858.
26. Torreggiani, A.; Tamba, M.; Trinchero, A.; Bonora, J. Copper(II)–Quercetin Complexes in Aqueous Solutions: Spectroscopic and Kinetic Properties. J. Mol. Struct. 2005, 744–747, 759–766.
27. Jurasekova, Z.; Torreggiani, A.; Tamba, M.; Sanchez-Cortes, S.; Garcia-Ramos, J. B. Raman and Surface-Enhanced Raman Scattering (SERS) Investigation of the Quercetin Interaction with Metals: Evidence of Structural Changing Processes in Aqueous Solution and on Metal Nanoparticles. J. Mol. Struct. 2009, 918, 129–137.
28. Guyot, S.; Vercauteren, J.; Cheynier, V. Structural Determination of Colourless and Yellow Dimers Resulting from (+)-Catechin Coupling Catalysed by Grape Polyphenoloxidase. Phytochemistry 1996, 42, pp. 1279‒1288.
29. Kumamoto, M.; Sonda, T.; Nagayama, K.; Tabata, M. Effects of pH and Metal Ions on Antioxidative Activities of Catechins. Biosci. Biotechnol. Biochem. 2001, 65, 126‒132.
30. Kasprzak, M. M.; Erxleben, A.; Ochocki, J. Properties and Applications of Flavonoid Metal Complexes. RSC Adv. 2015, 5, 45853‒45877.
31. Lee, M.; Rho, J.; Lee, D.-E.; Hong, S.; Choi, S.-J.; Messersmith, P. B.; Lee, H. Water Detoxification by a Substrate-Bound Catecholamine Adsorbent. ChemPlusChem 2012, 77, 987‒990.
32. Bahlakeh, G.; Ramezanzadeh, M.; Ramezanzadeh, B. Experimental and Theoretical Studies of the Synergistic Inhibition Effects between the Plant Leaves Extract (PLE) and Zinc Salt (ZS) in Corrosion Control of Carbon Steel in Chloride Solution. J. Mol. Liq. 2017, 248, 854‒870.
33. Yin, M.; Wu, C.-K.; Lou, Y.; Burda, C.; Koberstein, J. T.; Zhu, Y.; O’Brien, S. Copper Oxide Nanocrystals. J. Am. Chem. Soc. 2005, 127, 9506‒9511.
34. Gupta, K.; Bersani, M.; Darr, J. A. Highly Efficient Electro-Reduction of CO2 to Formic Acid by Nano-Copper. J. Mater. Chem. A 2016, 4, 13786‒13794.
35. Desentis-Mendoza, R. M.; Hernández-Sánchez, H.; Moreno, A.; Rojas del C., E.; Chel-Guerrero, L.; Tamariz, J.; Jaramillo-Flores, M. E. Enzymatic Polymerization of Phenolic Compounds Using Laccase and Tyrosinase from Ustilago maydis. Biomacromolecules 2006, 7, 1845‒1854.
36. Mejias, L.; Reihmann, M. H.; Sepulveda-Boza, S.; Ritter, H. New Polymers from Natural Phenols Using Horseradish or Soybean Peroxidase. Macromol. Biosci. 2002, 2, 24‒32.
37. Bukhari, S. B.; Memon, S.; Mahroof-Tahir, M.; Bhanger, M. I. Synthesis, Characterization and Antioxidant Activity Copper–Quercetin Complex. Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. 2009, 71, 1901‒1906.
38. Rotini, A.; Tornambè, A.; Cossi, R.; Iamunno, F.; Benvenuto, G.; Berducci, M. T.; Maggi, C.; Thaller, M. C.; Cicero, A. M.; Manfra, L.; Migliore, L. Salinity-Based Toxicity of CuO Nanoparticles, CuO-Bulk and Cu Ion to Vibrio anguillarum. Front. Microbiol. 2017, 8, 2076.
39. Lakhotia, S. R.; Mukhopadhyay, M.; Kumari, P. Cerium Oxide Nanoparticles Embedded Thin-Film Nanocomposite Nanofiltration Membrane for Water Treatment. Sci Rep 2018, 8, 4976.
40. Chang, C.-E.; Hsieh, C.-M.; Huang, S.-C.; Su, C.-Y.; Sheu, M.-T.; Ho, H.-O. Lecithin-Stabilized Polymeric Micelles (LsbPMs) for Delivering Quercetin: Pharmacokinetic Studies and Therapeutic Effects of Quercetin Alone and in Combination with Doxorubicin. Sci Rep 2018, 8, 17640.
41. Debnath, K.; Jana, N. R.; Jana, N. R. Quercetin Encapsulated Polymer Nanoparticle for Inhibiting Intracellular Polyglutamine Aggregation. ACS Appl. Bio Mater. 2019, Doi.org/10.1021/acsabm.9b00518.
42. Górniak, I.; Bartoszewski, R.; Króliczewski, J. Comprehensive Review of Antimicrobial Activities of Plant Flavonoids. Phytochem. Rev. 2019, 18, 241‒272.
43. Wang, S.; Yao, J.; Zhou, B.; Yang, J.; Chaudry, M. T.; Wang, M.; Xiao, F.; Li, Y.; Yin, W. Bacteriostatic Effect of Quercetin as an Antibiotic Alternative In Vivo and Its Antibacterial Mechanism In Vitro. J. Food Prot. 2018, 81, 68‒78.
44. Cady, N. C.; Behnke, J. L.; Strickland, A. D. Copper-Based Nanostructured Coatings on Natural Cellulose: Nanocomposites Exhibiting Rapid and Efficient Inhibition of a Multi-Drug Resistant Wound Pathogen, A. baumannii, and Mammalian Cell Biocompatibility In Vitro. Adv. Funct. Mater. 2011, 21, 2506–2514.
45. Applerot, G.; Lellouche, J.; Lipovsky, A.; Nitzan, Y.; Lubart, R.; Gedanken, A.; Banin, E. Understanding the Antibacterial Mechanism of CuO Nanoparticles: Revealing the Route of Induced Oxidative Stress. Small 2012, 8, 3326‒3337.
46. Nakao, N.; Kurokawa, T.; Nonami, T.; Tumurkhuu, G.; Koide, N.; Yokochi, T. Hydrogen Peroxide Induces The Production of Tumor Necrosis Factor-α in RAW 264.7 Macrophage Cells via Activation of p38 and Stress-Activated Protein Kinase. Innate Immun. 2008, 14, 190‒196.
47. Xu, D.; Hu, M.-J.; Wang, Y.-Q.; Cui, Y.-L. Antioxidant Activities of Quercetin and Its Complexes for Medicinal Application. Molecules 2019, 24, 1123.
48. Chereddy, K. K.; Lopes, A.; Koussoroplis, S.; Payen, V.; Moia, C.; Zhu, H.; Sonveaux, P.; Carmeliet, P.; des Rieux, P.; Vandermeulen, G.; Préat, V. Combined Effects of PLGA and Vascular Endothelial Growth Factor Promote the Healing of Non-Diabetic and Diabetic Wounds. Nanomed.-Nanotechnol. Biol. Med. 2015, 11, 1975‒1984.
49. Khanna, S.; Biswas, S.; Shang, Y.; Collard, E.; Azad, A.; Kauh, C.; Bhasker, V.; Gordillo, G. M.; Sen, C. K.; Roy, S. Macrophage Dysfunction Impairs Resolution of Inflammation in the Wounds of Diabetic Mice. PLoS One 2010, 5, e9539.