Morphological, structural and rheological properties of beta-cyclodextrin based polypseudorotaxane gels
(3389-3395) Polymer 52 #15 (2011)
Kuo and Lai  of National Taiwan University, Taiwan, made supramolecular self-assembled gels of polypseudorotaxane (PPR) through sequential inclusion complexations between beta-cyclodextrin (β-CD) and reverse Pluronic® (RPL, or PPG–PEG–PPG).  β-CD/RPL mixtures in water incubated at 65 °C (β-CD/RPL-W-65) underwent PPR rearrangement, resulting in larger crystallites and a more integrate net-like structure, therefore yielding higher gel strength as compared with β-CD/RPL mixture in water incubated at 25 °C.  (RDC 7/7/2011)

Quantum dot-pseudopolyrotaxane supramolecules as anticancer drug delivery systems
(2401-2413) Polymer 52 #11 (2011)
Adeli et al of Lorestan University and Tehran University of Medical Sciences, Iran,  synthesized pseudopolyrotaxanes (Ps-PR) consisting of α-cyclodextrin rings, polyethylene glycol axes and end triazine groups.   Dissociation of the α-cyclodextrin rings from the polyethylene glycol axes was avoided by the host–guest relationship between its end triazine groups and β-cyclodextrins conjugated onto the surface of quantum dots (β-CD-graft-QDs), leading to a new type of the dynamic polyrotaxanes in which QDs play the role of stoppers noncovalently.  Stability of the synthesized supramolecules was depended on the efficiency of the host–guest relationships between the end triazine groups of Ps-PR and β-CD-graft-QDs through which release of α-cyclodextrin rings from the polyethylene glycol axes was controlled.
To prove the efficacy of the synthesized supramolecules as drug delivery systems (DDSs) cisplatin (Cis-Diamminedichloroplatinum (CDDP) a platinum-based chemotherapy drug) and folic acid as a tumor-recognition module were conjugated to their stoppers and they were subjected to the receptor-mediated endocytosis and release inside the cancer cells, murine colon adenocarcinoma tumor C26. Then, it was proved that these tumor-targeting DDSs are promising systems for future cancer therapy. Rate of the release of the drugs, conjugated to the functional groups of stoppers was also investigated.  (RDC 6/2/2011)

Heat-induced Supramolecular Crosslinking of Dumbbell-shaped PEG with β-CD Dimer Based on Reversible Loose-fit Rotaxanation
(211–215)Macromolecular Chemistry and Physics 212 #3 (2011)
Katoono  et al of the Japan Advanced Institute of Science and Technology, Japan developed supramolecular crosslinking was studied in reversible loose-fit rotaxanation between a size-mismatched ring and a dumbbell-shaped chain attached to bulky terminals through slipping of the crosslinked rings onto the chain using a combination of β-cyclodextrin (β-CD) and poly(ethylene glycol) (PEG) in water. The mixing led to a drastic increase in viscosity only at an elevated temperature, while a PEG chain without any terminals or with bulkier terminals produced no change in the mixed solution under the same conditions. The dynamic viscoelastic properties of the mixed solution of the proper dumbbell-shaped PEG chain and β-CD dimer in water were also investigated to indicate network formation through heat-induced supramolecular crosslinking.  (RDC 2/24/2011)

Polyrotaxane derivatives. II. Preparation and characterization of ionic polyrotaxanes and ionic slide-ring gels
(2199–2209) Journal of Polymer Science Part A: Polymer  Chemistry 49 #10 (2011)
Araki of Shinshu University, Japan, prepared four types of ionic polyrotaxane (PR) derivatives, that is, carboxymethylated, sulfoethylated, diethylaminoethylated, and trimethylammoniohydroxypropylated PRs, starting from the same PR consisting of poly(ethylene glycol) as an axis and α-cyclodextrins as ring molecules.  Cross-linking of sulfoethylated and quaternized PRs yielded ionic slide-ring gels carrying sulfoethyl and quaternary ammonium groups on the mobile cross-links, respectively. The former gel showed intriguing phenomena, including a large degree of swelling of up to 1147, drastic change in its swelling ratio by the presence of electrolyte and bending under a moderate applied electric field (7 V/cm).  (RDC 4/4/2011)

Mono-, Di-, or Triazidated Cyclodextrin-Based Polyrotaxanes for Facile and Efficient Functionalization via Click Chemistry
(326–331) Macromolecular Rapid Communications 32 #3 (2011)
Hyun and Yui of the Japan Advanced Institute of Science and Technology, Japan, prepared azidated polyrotaxanes comprising PEG (MW = 3 000 and 20 000 g · mol−1) and mono-, di-, or triazidated α-cyclodextrins are prepared in a water/DMSO solution in a one-pot synthesis.  The azidated polyrotaxanes are then allowed to conjugate with propargyl-modified mannose as a ligand via click chemistry. The results verify the achievement of ligand-density-controlled polyrotaxanes.  (RDC 2/24/2011)

Effect of preparation conditions for poly(ethylene glycol)/cyclodextrin polyrotaxane on modes of end-capping reactions and decomposition of the yielded polyrotaxane  
(pages 5258–5264)Journal of Polymer Science Part A: Polymer  Chemistry 48 #22 (2010)
Araki  from Shinshu University, Japan   produced PEG/CD polyrotaxane with and without end-capping molecules (adamantanamine or diphenylethylamine).   Ester endcapped polyrotaxanes decomposed over months at room temperature and humidity.  (RDC 11/9/2010)