Carborane Guests for Cucurbit[7]uril Facilitate Strong Binding and on Demand Removal

Author(s):  
Anna Kataki-Anastasakou ◽  
Jonathan C. Axtell ◽  
Selena Hernandez ◽  
RafalM. Dziedzic ◽  
Gary J. Balaich ◽  
...  

High affinity guest have been reported for the macrocyclic host cucurbit[7]uril (CB[7]), enabling widespread applications, but preventing CB[7] materials from being returned to their guest-free state for reuse. Here we present polyhedral boron clusters (carboranes) as strongly-binding, yet easily removable, guests for CB[7]. Aided by a Pd-catalyzed coupling of an azide anion, we prepared boron-functionalized 9<i>-</i>amino and 9-ammonium modified <i>ortho-</i>carboranes that bind to CB[7] with a <i>K<sub>a</sub></i>=10<sup>10</sup> M<sup>-1</sup>. Upon treatment with base, the <i>ortho</i>-carboranes<i> </i>readily undergo deboronation to yield anionic <i>nido</i>-carborane, a poor guest of CB[7], facilitating recovery of guest-free CB[7]. We showcase the utility of the modified <i>ortho</i>-carborane guest by recycling a CB[7]-functionalized resin. With this report, we introduce stimuli-responsive decomplexation as an additional consideration in the design of high affinity host-guest complexes.

2020 ◽  
Author(s):  
Anna Kataki-Anastasakou ◽  
Jonathan C. Axtell ◽  
Selena Hernandez ◽  
RafalM. Dziedzic ◽  
Gary J. Balaich ◽  
...  

High affinity guest have been reported for the macrocyclic host cucurbit[7]uril (CB[7]), enabling widespread applications, but preventing CB[7] materials from being returned to their guest-free state for reuse. Here we present polyhedral boron clusters (carboranes) as strongly-binding, yet easily removable, guests for CB[7]. Aided by a Pd-catalyzed coupling of an azide anion, we prepared boron-functionalized 9<i>-</i>amino and 9-ammonium modified <i>ortho-</i>carboranes that bind to CB[7] with a <i>K<sub>a</sub></i>=10<sup>10</sup> M<sup>-1</sup>. Upon treatment with base, the <i>ortho</i>-carboranes<i> </i>readily undergo deboronation to yield anionic <i>nido</i>-carborane, a poor guest of CB[7], facilitating recovery of guest-free CB[7]. We showcase the utility of the modified <i>ortho</i>-carborane guest by recycling a CB[7]-functionalized resin. With this report, we introduce stimuli-responsive decomplexation as an additional consideration in the design of high affinity host-guest complexes.


2017 ◽  
Vol 48 ◽  
pp. 110-119 ◽  
Author(s):  
Hugh S. O’Neill ◽  
Caroline C. Herron ◽  
Conn L. Hastings ◽  
Roel Deckers ◽  
Adolfo Lopez Noriega ◽  
...  

2021 ◽  
Vol 9 (1) ◽  
pp. 38-50
Author(s):  
Hien Phan ◽  
Vincenzo Taresco ◽  
Jacques Penelle ◽  
Benoit Couturaud

Stimuli-responsive amphiphilic block copolymers obtained by PISA have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, redox agents, light or temperature.


2019 ◽  
Vol 296 ◽  
pp. 93-106 ◽  
Author(s):  
Ying Qu ◽  
Bingyang Chu ◽  
Xiawei Wei ◽  
Minyi Lei ◽  
Danrong Hu ◽  
...  

2020 ◽  
Vol 41 (24) ◽  
pp. 2000441
Author(s):  
Yue Zhao ◽  
Zuhao Li ◽  
Qiuju Li ◽  
Longfei Yang ◽  
Hou Liu ◽  
...  

2014 ◽  
Vol 66 ◽  
pp. 58-73 ◽  
Author(s):  
Yuanpei Li ◽  
Kai Xiao ◽  
Wei Zhu ◽  
Wenbin Deng ◽  
Kit S. Lam

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1319
Author(s):  
Baljinder Singh ◽  
Nutan Shukla ◽  
Junkee Kim ◽  
Kibeom Kim ◽  
Myoung-Hwan Park

On-demand drug delivery systems using nanofibers have attracted significant attention owing to their controllable properties for drug release through external stimuli. Near-infrared (NIR)-responsive nanofibers provide a platform where the drug release profile can be achieved by the on-demand supply of drugs at a desired dose for cancer therapy. Nanomaterials such as gold nanorods (GNRs) exhibit absorbance in the NIR range, and in response to NIR irradiation, they generate heat as a result of a plasmon resonance effect. In this study, we designed poly (N-isopropylacrylamide) (PNIPAM) composite nanofibers containing GNRs. PNIPAM is a heat-reactive polymer that provides a swelling and deswelling property to the nanofibers. Electrospun nanofibers have a large surface-area-to-volume ratio, which is used to effectively deliver large quantities of drugs. In this platform, both hydrophilic and hydrophobic drugs can be introduced and manipulated. On-demand drug delivery systems were obtained through stimuli-responsive nanofibers containing GNRs and PNIPAM. Upon NIR irradiation, the heat generated by the GNRs ensures shrinking of the nanofibers owing to the thermal response of PNIPAM, thereby resulting in a controlled drug release. The versatility of the light-responsive nanofibers as a drug delivery platform was confirmed in cell studies, indicating the advantages of the swelling and deswelling property of the nanofibers and on–off drug release behavior with good biocompatibility. In addition, the system has potential for the combination of chemotherapy with multiple drugs to enhance the effectiveness of complex cancer treatments.


2018 ◽  
Vol 57 (28) ◽  
pp. 8383-8394 ◽  
Author(s):  
Wenpei Fan ◽  
Bryant C. Yung ◽  
Xiaoyuan Chen

2018 ◽  
Author(s):  
Bart Van Beusekom ◽  
Tatjana Heidebrecht ◽  
Athanassios Adamopoulos ◽  
Alexander Fish ◽  
Els Pardon ◽  
...  

AbstractThe J-base Binding Protein 1 (JBP1) contributes to biosynthesis and maintenance of base J (β-D-glucosyl-hydroxymethyluracil), a modification of thymidine confined to some protozoa. Camelid (llama) single domain antibody fragments (nanobodies) targeting JBP1 were produced for use as crystallization chaperones. Surface plasmon resonance (SPR) screening identified Nb6 as a strong binder, recognising JBP1 with a 1:1 stoichiometry and high affinity (kD=30nM). Crystallisation trials of JBP1 in complex with Nb6, yielded crystals diffracting to 1.47Å resolution.However, the asymmetric unit dimensions and molecular replacement with a nanobody structure, clearly showed that the crystals of the expected complex with JBP1 were of the nanobody alone. Nb6 crystallizes in spacegroup P31 with two molecules in the asymmetric unit; its crystal structure was refined to a final resolution of 1.64Å. Ensemble refinement suggests that on the ligand-free state one of the complementarity determining regions (CDRs) is flexible while the other two adopt well-defined conformations.SynopsisA camelid single domain antibody fragment (nanobody) is shown to have high affinity towards its recognition target, the J-base binding protein 1 (JBP1). The serendipitous crystallisation of this nanobody alone, and its crystal structure solution and refinement to 1.64Å resolution are described. Ensemble refinement suggests that on the ligand-free state one of the complementarity determining regions (CDRs) is flexible while the other two adopt well-defined conformations.


2020 ◽  
Vol 109 ◽  
pp. 110495 ◽  
Author(s):  
Clément Bombonnel ◽  
Cédric Vancaeyzeele ◽  
Gerald Guérin ◽  
Frédéric Vidal

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