10.1007/s40097-021-00432-7

Metal–polymer-coordinated complexes as potential nanovehicles for drug delivery

  • Hamed Tabasi1,
  • Maryam Babaei2,
  • Khalil Abnous2,
  • Seyed Mohammad Taghdisi3,
  • Amir Sh. Saljooghi4,
  • Mohammad Ramezani1,
  • Mona Alibolandi*1,
  1. Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, IR Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, IR
  2. Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, IR
  3. Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, IR
  4. Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, IR

Published in Issue 25-07-2021

How to Cite

Tabasi, H., Babaei, M., Abnous, K., Taghdisi, S. M., Saljooghi, A. S., Ramezani, M., & Alibolandi, M. (2021). Metal–polymer-coordinated complexes as potential nanovehicles for drug delivery. Journal of Nanostructure in Chemistry, 11(4 (December 2021). https://doi.org/10.1007/s40097-021-00432-7
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Abstract

Abstract Hybrid metal–polymer-coordinated complex, as a class of supramolecular coordinated complex, represents a great opportunity for the development of the multipurpose intelligent system of nanomedicine in drug delivery. These structures and their interesting functions are created after the self-assembly process and coordination bond formation between different metal ions and polymers. There is an important difference between metal–organic framework (MOF) and metal–polymer-coordinated complex (MPC). MPCs are convergent structures made of metal and polymeric linkers’ combination in 1D, 2D and 3D architectures while MOFs are divergent 3D network structures with metal cores and organic ligands linkers. Until now, many reviews have been published about MOF-based systems while there is no comprehensive review on MPCs. Moreover, the MPCs have exhibited potential nano-chemistry properties to be utilized in nanomedicine applications as smart and multifunction nanovesicles for drug delivery. In this review, the MPC architectures, their synthesis process and their applications in drug delivery are described. The advantages and disadvantages of MPC are summarized. We also categorized smart MPCs for on-demand drug release and intelligent delivery. Graphic abstract

Keywords

  • Nanomedicine,
  • Drug delivery,
  • Metal–polymer-coordinated complex,
  • Self-assembly,
  • Metallic organic framework

References

  1. Wei (2020) Metals in polymers: hybridization enables new functions 8(45) (pp. 15956-15980)
  2. Clarke (2003) Ruthenium metallopharmaceuticals 236(1–2) (pp. 209-233) https://doi.org/10.1016/S0010-8545(02)00312-0
  3. Zhang et al. (2021) Protection of magnesium alloys: from physical barrier coating to smart self-healing coating https://doi.org/10.1016/j.jallcom.2020.157010
  4. Callari (2014) Polymers with platinum drugs and other macromolecular metal complexes for cancer treatment 39(9) (pp. 1614-1643) https://doi.org/10.1016/j.progpolymsci.2014.05.002
  5. Cai (2020) A nanostrategy for efficient imaging-guided antitumor therapy through a stimuli-responsive branched polymeric prodrug 7(6) https://doi.org/10.1002/advs.201903243
  6. Batten (2012) Coordination polymers, metal–organic frameworks and the need for terminology guidelines 14(9) https://doi.org/10.1039/c2ce06488j
  7. Biradha et al. (2009) Coordination polymers versus metal−organic frameworks 9(7) (pp. 2969-2970) https://doi.org/10.1021/cg801381p
  8. Casini et al. (2017) The promise of self-assembled 3D supramolecular coordination complexes for biomedical applications 56(24) (pp. 14715-14729) https://doi.org/10.1021/acs.inorgchem.7b02599
  9. Tu (2020) Self-recognizing and stimulus-responsive carrier-free metal-coordinated nanotheranostics for magnetic resonance/photoacoustic/fluorescence imaging-guided synergistic photo-chemotherapy 8(26) (pp. 5667-5681) https://doi.org/10.1039/D0TB00850H
  10. Zhou (2015) Supramolecular self-assembly of nucleotide–metal coordination complexes: from simple molecules to nanomaterials (pp. 107-143) https://doi.org/10.1016/j.ccr.2015.02.007
  11. Thakur (2018) Multifunctional inosine monophosphate coordinated metal-organic hydrogel: multistimuli responsiveness, self-healing properties, and separation of water from organic solvents 6(7) (pp. 8659-8671) https://doi.org/10.1021/acssuschemeng.8b00963
  12. Ezzayani (2021) Building-up novel coordination polymer with magnesium porphyrin: Synthesis, molecular structure, photophysical properties and spectroscopic characterization. Potential application as antibacterial agent https://doi.org/10.1016/j.ica.2020.119960
  13. Wang (2017) Organelle-specific triggered release of immunostimulatory oligonucleotides from intrinsically coordinated DNA–metal–organic frameworks with soluble exoskeleton 139(44) (pp. 15784-15791) https://doi.org/10.1021/jacs.7b07895
  14. Jańczewski (2012) Organometallic polymeric carriers for redox triggered release of molecular payloads 22(13) https://doi.org/10.1039/c2jm15755a
  15. Duangjai (2014) Combination cytotoxicity of backbone degradable HPMA copolymer gemcitabine and platinum conjugates toward human ovarian carcinoma cells 87(1) (pp. 187-196) https://doi.org/10.1016/j.ejpb.2013.11.008
  16. Cai (2021) Cathepsin B-responsive and gadolinium-labeled branched glycopolymer-PTX conjugate-derived nanotheranostics for cancer treatment 11(2) (pp. 544-559) https://doi.org/10.1016/j.apsb.2020.07.023
  17. Anderegg (2005) Critical evaluation of stability constants of metal complexes of complexones for biomedical and environmental applications* (IUPAC Technical Report) 77(8) (pp. 1445-1495) https://doi.org/10.1351/pac200577081445
  18. Wang (2018) Acid-triggered synergistic chemo-photodynamic therapy systems based on metal-coordinated supramolecular interaction 106(11) (pp. 2955-2962) https://doi.org/10.1002/jbm.a.36484
  19. Ezzayani (2017) Complex of hexamethylenetetramine with magnesium-tetraphenylporphyrin: synthesis, structure, spectroscopic characterizations and electrochemical properties (pp. 412-418) https://doi.org/10.1016/j.molstruc.2017.02.054
  20. Matsuoka and Nabeshima (2018) Functional supramolecular architectures of dipyrrin complexes https://doi.org/10.3389/fchem.2018.00349
  21. MacLachlan (2000) Shaped ceramics with tunable magnetic properties from metal-containing polymers 287(5457) (pp. 1460-1463) https://doi.org/10.1126/science.287.5457.1460
  22. Driva (2020) Complexes of end-functionalized polystyrenes carrying amine end-group with transition metals: association effects in organic solvents 10(1) (pp. 4764-4773)
  23. Liu (2017) Light-controlled drug release from singlet-oxygen sensitive nanoscale coordination polymers enabling cancer combination therapy (pp. 40-48) https://doi.org/10.1016/j.biomaterials.2017.09.007
  24. Li (2021) Five lead(II) coordinated polymers assembled from asymmetric azoles carboxylate ligands: Synthesis, structures and fluorescence properties https://doi.org/10.1016/j.ica.2020.120035
  25. Solorzano (2018) Versatile iron-catechol-based nanoscale coordination polymers with antiretroviral ligand functionalization and their use as efficient carriers in HIV/AIDS therapy 7(1) (pp. 178-186) https://doi.org/10.1039/C8BM01221K
  26. Yan (2010) Redox responsive molecular assemblies based on metallic coordination polymers 6(14) https://doi.org/10.1039/b927331j
  27. Ovsyannikov (2017) Coordination polymers based on calixarene derivatives: structures and properties (pp. 151-186) https://doi.org/10.1016/j.ccr.2017.09.004
  28. Cook, T.R., Stang, P.J.: Coordination-driven supramolecular macromolecules via the directional bonding approach, In Hierarchical macromolecular structures: 60 years after the Staudinger Nobel Prize I. Advances in Polymer Science, vol. 261, pp. 229–248. Springer, Cham (2013)
  29. Lewis (2012) Stimuli-responsive Pd2L4metallosupramolecular cages: towards targeted cisplatin drug delivery 3(3) (pp. 778-784) https://doi.org/10.1039/C2SC00899H
  30. Yoshizawa et al. (2006) Diels-alder in aqueous molecular hosts: unusual regioselectivity and efficient catalysis 312(5771) (pp. 251-254) https://doi.org/10.1126/science.1124985
  31. Bunzen (2012) Self-assembly of M24L48 polyhedra based on empirical prediction 51(13) (pp. 3161-3163) https://doi.org/10.1002/anie.201108731
  32. Han (2017) Bioconjugation strategies to couple supramolecular exo-functionalized palladium cages to peptides for biomedical applications 53(8) (pp. 1405-1408) https://doi.org/10.1039/C6CC08937B
  33. Lee et al. (2018) Stimuli-responsive supramolecular gels constructed by hierarchical self-assembly based on metal-ligand coordination and host–guest recognition 39(22) https://doi.org/10.1002/marc.201800465
  34. Datta et al. (2018) Hierarchical assemblies of supramolecular coordination complexes 51(9) (pp. 2047-2063) https://doi.org/10.1021/acs.accounts.8b00233
  35. Wei (2020) Metals in polymers: hybridization enables new functions 8(45) (pp. 15956-15980) https://doi.org/10.1039/D0TC03810E
  36. Mbaba et al. (2020) Recent advances in the biological investigation of organometallic platinum-group metal (Ir, Ru, Rh, Os, Pd, Pt) complexes as antimalarial agents 25(22) https://doi.org/10.3390/molecules25225276
  37. Amiri (2018) Synthesis, molecular structure, photophysical properties and spectroscopic characterization of new 1D-magnesium(II) porphyrin-based coordination polymer 44(9) (pp. 5583-5595) https://doi.org/10.1007/s11164-018-3442-9
  38. Li (2019) Twelve cadmium(II) coordination frameworks with asymmetric pyridinyl triazole carboxylate: syntheses, structures, and fluorescence properties 19(7) (pp. 3785-3806) https://doi.org/10.1021/acs.cgd.9b00241
  39. Pitto-Barry (2011) Encapsulation of pyrene-functionalized poly(benzyl ether) dendrons into a water-soluble organometallic cage 6(6) (pp. 1595-1603) https://doi.org/10.1002/asia.201100136
  40. Mao (2020) A zipped-up tunable metal coordinated cationic polymer for nanomedicine 8(7) (pp. 1350-1358) https://doi.org/10.1039/C9TB02965F
  41. Qi (2017) Cationic Salecan-based hydrogels for release of 5-fluorouracil 7(24) (pp. 14337-14347) https://doi.org/10.1039/C7RA01052D
  42. Qi (2016) Development of novel hydrogels based on Salecan and poly(N-isopropylacrylamide-co-methacrylic acid) for controlled doxorubicin release 6(74) (pp. 69869-69881) https://doi.org/10.1039/C6RA10716H
  43. Wei (2016) Smart macroporous salecan/poly(N, N-diethylacrylamide) semi-IPN hydrogel for anti-inflammatory drug delivery 2(8) (pp. 1386-1394) https://doi.org/10.1021/acsbiomaterials.6b00318
  44. Su (2020) Facile fabrication of functional hydrogels consisting of pullulan and polydopamine fibers for drug delivery (pp. 366-374) https://doi.org/10.1016/j.ijbiomac.2020.06.283
  45. Yan (2020) A multifunctional metal-biopolymer coordinated double network hydrogel combined with multi-stimulus responsiveness, self-healing, shape memory and antibacterial properties 8(11) (pp. 3193-3201) https://doi.org/10.1039/D0BM00425A
  46. Kniazeva (2020) Nuclearity control in calix[4]arene-based zinc(ii) coordination complexes 22(44) (pp. 7693-7703) https://doi.org/10.1039/D0CE01232G
  47. Dutta (2020) Oxalato bridged coordination polymer of manganese(iii) involving unconventional O⋯π-hole(nitrile) and antiparallel nitrile⋯nitrile contacts: antiproliferative evaluation and theoretical studies 44(46) (pp. 20021-20038) https://doi.org/10.1039/D0NJ03712E
  48. Amiri (2017) Synthesis, crystal structure and spectroscopic characterizations of porphyrin-based Mg(II) complexes—potential application as antibacterial agent 73(50) (pp. 7011-7016) https://doi.org/10.1016/j.tet.2017.10.029
  49. Li (2020) Lanthanide-based hydrogels with adjustable luminescent properties synthesized by thiol-Michael addition https://doi.org/10.1016/j.dyepig.2019.108091
  50. Weng et al. (2018) Dynamic coordination of Eu–Iminodiacetate to control fluorochromic response of polymer hydrogels to multistimuli 30(11) https://doi.org/10.1002/adma.201706526
  51. Ma (2016) Synthesis, characterization, and magnetic properties of two transition metal coordination polymers based on 2,5-furandicarboxylic acid and N-donor ligands 26(5) (pp. 1053-1060) https://doi.org/10.1007/s10904-016-0429-0
  52. Dawn (2012) A trinuclear silver coordination polymer from a bipyridine bis-urea macrocyclic ligand and silver triflate (pp. 88-92) https://doi.org/10.1016/j.inoche.2011.09.045
  53. Dulcevscaia (2013) New copper(II) complexes with isoconazole: Synthesis, structures and biological properties (pp. 106-114) https://doi.org/10.1016/j.poly.2012.10.040
  54. Lopez and Liu (2013) Light-activated metal-coordinated supramolecular complexes with charge-directed self-assembly 117(7) (pp. 3653-3661) https://doi.org/10.1021/jp3121403
  55. Đurić (2020) New polynuclear 1,5-naphthyridine-silver(I) complexes as potential antimicrobial agents: the key role of the nature of donor coordinated to the metal center https://doi.org/10.1016/j.jinorgbio.2019.110872
  56. Hu (2017) Dual-physical cross-linked tough and photoluminescent hydrogels with good biocompatibility and antibacterial activity 38(10) https://doi.org/10.1002/marc.201600788
  57. Cook et al. (2013) Metal-organic frameworks and self-assembled supramolecular coordination complexes: comparing and contrasting the design, synthesis, and functionality of metal-organic materials 113(1) (pp. 734-777) https://doi.org/10.1021/cr3002824
  58. Wang (2018) A facile strategy for self-healing polyurethanes containing multiple metal–ligand bonds 39(6) https://doi.org/10.1002/marc.201700678
  59. Wei (2020) Adaptable Eu-containing polymeric films with dynamic control of mechanical properties in response to moisture 16(9) (pp. 2276-2284) https://doi.org/10.1039/C9SM02440A
  60. Liu (2018) C-coordinated O-carboxymethyl chitosan metal complexes: Synthesis, characterization and antifungal efficacy (pp. 68-77) https://doi.org/10.1016/j.ijbiomac.2017.07.176
  61. Nie (2007) Self-assembly of metal-polymer analogues of amphiphilic triblock copolymers 6(8) (pp. 609-614) https://doi.org/10.1038/nmat1954
  62. Gao et al. (2013) Plasmonic nanocomposites: Polymer-guided strategies for assembling metal nanoparticles 5(13) (pp. 5677-5691) https://doi.org/10.1039/c3nr01091k
  63. Tandon (2020) Self-assembly of antiferromagnetically-coupled copper(II) supramolecular architectures with diverse structural complexities 25(23) https://doi.org/10.3390/molecules25235549
  64. Carnes et al. (2014) Transmetalation of self-assembled, supramolecular complexes 43(6) (pp. 1825-1834) https://doi.org/10.1039/C3CS60349K
  65. Abolmaali (2016) Chemically crosslinked nanogels of PEGylated poly ethyleneimine (l-histidine substituted) synthesized via metal ion coordinated self-assembly for delivery of methotrexate: Cytocompatibility, cellular delivery and antitumor activity in resistant cells (pp. 897-907) https://doi.org/10.1016/j.msec.2016.02.045
  66. Li and Li (2018) A luminescent porous metal–organic framework with Lewis basic pyridyl sites as a fluorescent chemosensor for TNP detection (pp. 51-54) https://doi.org/10.1016/j.inoche.2018.01.013
  67. Zhang (2018) A multifunctional ternary Cu(II)-carboxylate coordination polymeric nanocomplex for cancer thermochemotherapy 549(1–2) (pp. 1-12)
  68. Cao (2012) Coordination-responsive selenium-containing polymer micelles for controlled drug release 3(12) https://doi.org/10.1039/c2sc21315j
  69. Beck and Rowan (2003) Multistimuli, multiresponsive metallo-supramolecular polymers 125(46) (pp. 13922-13923) https://doi.org/10.1021/ja038521k
  70. Hoke (1989) In vivo and in vitro cardiotoxicity of a gold-containing antineoplastic drug candidate in the rabbit 100(2) (pp. 293-306) https://doi.org/10.1016/0041-008X(89)90315-3
  71. Tiekink (2002) Gold derivatives for the treatment of cancer 42(3) (pp. 225-248) https://doi.org/10.1016/S1040-8428(01)00216-5
  72. To (2009) Gold(III) porphyrin complex is more potent than cisplatin in inhibiting growth of nasopharyngeal carcinoma in vitro and in vivo 124(8) (pp. 1971-1979) https://doi.org/10.1002/ijc.24130
  73. Zava (2010) Evidence for drug release from a metalla-cage delivery vector following cellular internalisation 16(5) (pp. 1428-1431) https://doi.org/10.1002/chem.200903216
  74. Barry (2011) Excellent correlation between drug release and portal size in metalla-cage drug-delivery systems 17(35) (pp. 9669-9677)
  75. Mattsson (2010) Drug delivery of lipophilic pyrenyl derivatives by encapsulation in a water soluble metalla-cage 39(35) (pp. 8248-8255) https://doi.org/10.1039/c0dt00436g
  76. Zheng (2015) Encapsulation of Pt(IV) prodrugs within a Pt(II) cage for drug delivery 6(2) (pp. 1189-1193) https://doi.org/10.1039/C4SC01892C
  77. Schmidt (2016) Evaluation of new palladium cages as potential delivery systems for the anticancer drug cisplatin 22(7) (pp. 2253-2256) https://doi.org/10.1002/chem.201504930
  78. Postupalenko (2015) Protein delivery system containing a nickel-immobilized polymer for multimerization of affinity-purified his-tagged proteins enhances cytosolic transfer 54(36) (pp. 10583-10586) https://doi.org/10.1002/anie.201505437
  79. Fujita (2012) Protein encapsulation within synthetic molecular hosts https://doi.org/10.1038/ncomms2093
  80. Wang (2020) Facile fabrication of a controlled polymer brush-type functional nanoprobe for highly sensitive determination of alpha fetoprotein 12(36) (pp. 4438-4446) https://doi.org/10.1039/D0AY01151G
  81. Wang (2016) Synthesis of PGMA/AuNPs amplification platform for the facile detection of tumor markers (pp. 534-541) https://doi.org/10.1016/j.matchemphys.2016.09.012
  82. Kumar (2008) DNA binding and biological studies of some novel water-soluble polymer-copper(II)-phenanthroline complexes 43(10) (pp. 2082-2091) https://doi.org/10.1016/j.ejmech.2007.09.017
  83. Badea et al. (2020) Improvement in the pharmacological profile of copper biological active complexes by their incorporation into organic or inorganic matrix 25(24) https://doi.org/10.3390/molecules25245830
  84. Lum (2013) A gold(III) porphyrin complex as an anti-cancer candidate to inhibit growth of cancer-stem cells 49(39) (pp. 4364-4366) https://doi.org/10.1039/C2CC37366A
  85. Zhang (2012) Organogold(III) supramolecular polymers for anticancer treatment 51(20) (pp. 4882-4886) https://doi.org/10.1002/anie.201108466
  86. Zhang (2017) A surface-grafted ligand functionalization strategy for coordinate binding of doxorubicin at surface of PEGylated mesoporous silica nanoparticles: toward pH-responsive drug delivery (pp. 138-145) https://doi.org/10.1016/j.colsurfb.2016.10.018
  87. Shahin et al. (2014) Polymeric micelles for pH-responsive delivery of cisplatin 22(7) (pp. 629-637) https://doi.org/10.3109/1061186X.2014.921925
  88. Song (2016) Temperature responsive polymer brushes grafted from graphene oxide: an efficient fluorescent sensing platform for 2,4,6-trinitrophenol 4(29) (pp. 7083-7092) https://doi.org/10.1039/C6TC00898D
  89. Ren (2020) A metal-polyphenol-coordinated nanomedicine for synergistic cascade cancer chemotherapy and chemodynamic therapy 32(6) https://doi.org/10.1002/adma.201906024
  90. Ruan (2019) Doxorubicin-metal coordinated micellar nanoparticles for intracellular codelivery and chemo/chemodynamic therapy in vitro 2(11) (pp. 4703-4707) https://doi.org/10.1021/acsabm.9b00879
  91. Hwang (2014) pH-responsive robust polymer micelles with metal–ligand coordinated core cross-links 50(33) (pp. 4351-4353) https://doi.org/10.1039/c4cc01584c
  92. Zhao (2011) Surface functionalization of porous coordination nanocages via click chemistry and their application in drug delivery 23(1) (pp. 90-93) https://doi.org/10.1002/adma.201003012
  93. Sun and Che (2009) The anti-cancer properties of gold(III) compounds with dianionic porphyrin and tetradentate ligands 253(11–12) (pp. 1682-1691) https://doi.org/10.1016/j.ccr.2009.02.017
  94. Che (2003) Gold(iii) porphyrins as a new class of anticancer drugs: cytotoxicity, DNA binding and induction of apoptosis in human cervix epitheloid cancer https://doi.org/10.1039/b303294a
  95. Sun (2010) Stable anticancer gold(III)-porphyrin complexes: effects of porphyrin structure 16(10) (pp. 3097-3113) https://doi.org/10.1002/chem.200902741
  96. Chow (2010) A gold(III) porphyrin complex with antitumor properties targets the Wnt/beta-catenin pathway 70(1) (pp. 329-337) https://doi.org/10.1158/0008-5472.CAN-09-3324
  97. Tabasi (2021) pH-responsive and CD44-targeting by Fe3O4/MSNs-NH2 nanocarriers for Oxaliplatin loading and colon cancer treatment https://doi.org/10.1016/j.inoche.2020.108430
  98. Pan (2014) PEGylated dendritic diaminocyclohexyl-platinum (II) conjugates as pH-responsive drug delivery vehicles with enhanced tumor accumulation and antitumor efficacy 35(38) (pp. 10080-10092) https://doi.org/10.1016/j.biomaterials.2014.09.006
  99. Fricker (2007) Metal based drugs: from serendipity to design (pp. 4903-4917) https://doi.org/10.1039/b705551j
  100. Xu (2019) Photo-controlled release of metal ions using triazoline-containing amphiphilic copolymers 10(26) (pp. 3585-3596) https://doi.org/10.1039/C9PY00406H
  101. Ding (2006) Synthesis and characterization of temperature-responsive copolymer of PELGA modified poly(N-isopropylacrylamide) 47(5) (pp. 1575-1583) https://doi.org/10.1016/j.polymer.2005.12.018
  102. Parikh (2011) Evaluating glutamate and aspartate binding mechanisms to rutile (α-TiO2) via ATR-FTIR spectroscopy and quantum chemical calculations 27(5) (pp. 1778-1787) https://doi.org/10.1021/la103826p
  103. Balamurugan et al. (2013) π-Conjugated polymer–Eu3+complexes: versatile luminescent molecular probes for temperature sensing 1(6) (pp. 2256-2266) https://doi.org/10.1039/C2TA00472K
  104. Ding et al. (2015) Enzyme-responsive polymer assemblies constructed through covalent synthesis and supramolecular strategy 51(6) (pp. 996-1003) https://doi.org/10.1039/C4CC05878J
  105. Chandrawati (2016) Enzyme-responsive polymer hydrogels for therapeutic delivery 241(9) (pp. 972-979) https://doi.org/10.1177/1535370216647186
  106. Nivorozhkin (2001) Enzyme-activated Gd(3+) magnetic resonance imaging contrast agents with a prominent receptor-induced magnetization enhancement 40(15) (pp. 2903-2906) https://doi.org/10.1002/1521-3773(20010803)40:15<2903::AID-ANIE2903>3.0.CO;2-N
  107. Garcia (2016) Multi-responsive coordination polymers utilising metal-stabilised, dynamic covalent imine bonds 52(58) (pp. 9059-9062) https://doi.org/10.1039/C6CC00500D
  108. Guan (2019) Enzyme-responsive sulfatocyclodextrin/prodrug supramolecular assembly for controlled release of anti-cancer drug chlorambucil 55(7) (pp. 953-956) https://doi.org/10.1039/C8CC09047E
  109. Villemin (2019) Polymer encapsulation of ruthenium complexes for biological and medicinal applications 3(4) (pp. 261-282) https://doi.org/10.1038/s41570-019-0088-0
  110. Feng (2011) Structurally sophisticated octahedral metal complexes as highly selective protein kinase inhibitors 133(15) (pp. 5976-5986) https://doi.org/10.1021/ja1112996
  111. Courtois (2020) Redox-responsive colloidal particles based on coordination polymers incorporating viologen units 59(9) (pp. 6100-6109) https://doi.org/10.1021/acs.inorgchem.0c00161
  112. Tao and Yin (2020) Redox-responsive coordination polymers of dopamine-modified hyaluronic acid with copper and 6-mercaptopurine for targeted drug delivery and improvement of anticancer activity against cancer cells 12(5) https://doi.org/10.3390/polym12051132
  113. Abdul-Hassan (2018) Redox-triggered folding of self-assembled coordination polymers incorporating viologen units 24(49) (pp. 12961-12969) https://doi.org/10.1002/chem.201802088
  114. Shen (2017) Renal-clearable ultrasmall coordination polymer nanodots for chelator-free (64)Cu-labeling and imaging-guided enhanced radiotherapy of cancer 11(9) (pp. 9103-9111) https://doi.org/10.1021/acsnano.7b03857