Modification of polyfluorene nanoparticles via inclusion complexation based on cyclodextrin for lectin sensing and cell imaging

A super-stretchable, self-healing and injectable supramolecular hydrogel constructed by a host–guest crosslinker

Supramolecular hydrogels based on host–guest interactions have drawn considerable attention due to their unique properties and promising applications.

3D hydrogel stem cell niche controlled by host-guest interaction affects stem cell fate and survival rate

Host-guest interaction using β-cyclodextrin (β-CD) and adamantane (Ad) allows facile modulation of guest molecule concentration in 3D hydrogels. Based on this phenomenon, we prepared a thermosensitive poly(organophosphazene) bearing β-CD hydrogel (β-CD PPZ, as host) and Ad-Arg-Gly-Asp (Ad-RGD, as guest). The structures of synthesized thermosensitive β-CD PPZ and Ad-RGD were confirmed by ¹H NMR and FT-IR. The β-CD PPZ/Ad-RGD mixture was prepared by simple mixing and elicited thermosensitive properties with the formation of gelation in all Ad-RGDs mixing proportions at the body temperature. Strong and controlled host-guest interactions between β-CD PPZ and Ad-RGD were observed in 2D-NOESY, DLS, and TEM. Regulated MSC behaviors were elicited based on the use of controlled Ad-RGD amounts at the level of in vitro and in vivo. As the amount of Ad-RGD was increased in the β-CD PPZ hydrogel, MSC survival rate was enhanced and was prone to express osteogenic factors. While Ad-RGD is absent or low in hydrogel, relatively poor MSC survival rate and adipogenesis were exhibited. Altogether, we verified that survival rate and differentiation of MSCs could be controlled by host-guest interaction system with thermosensitive 3D hydrogel. This proposed 3D hydrogel controlling system with host-guest interaction is expected to be a platform technology as changing guest molecules.

Chemistry and engineering of cyclodextrins for molecular imaging

Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides bearing a basket-shaped topology with an "inner-outer" amphiphilic character. The abundance of hydroxyl groups enables CDs to be functionalized with multiple targeting ligands and imaging elements. The imaging time, and the payload of different imaging elements, can be tuned by taking advantage of the commercial availability of CDs with different sizes of the cavity. This review aims to offer an outlook of the chemistry and engineering of CDs for the development of molecular probes. Complexation thermodynamics of CDs, and the corresponding implications for probe design, are also presented with examples demonstrating the structural and physiochemical roles played by CDs in the full ambit of molecular imaging. We hope that this review not only offers a synopsis of the current development of CD-based molecular probes, but can also facilitate translation of the incremental advancements from the laboratory to real biomedical applications by illuminating opportunities and challenges for future research.

Conjugated Polymer Nanoparticles for Bioimaging

During the last decade, conjugated polymers have emerged as an interesting class of fluorescence imaging probes since they generally show high fluorescence brightness, high photostability, fast emission rates, non-blinking behavior and low cytotoxicity. The main concern related to most conjugated polymers is their lack of hydrophilicity and thereby poor bio-availability. This can, however, be overcome by the formulation of conjugated polymer nanoparticles in aqueous medium. This review provides an overview of the different techniques employed for the preparation of conjugated polymer nanoparticles, together with methods to improve their photoluminescence quantum yields. For selective targeting of specific cells, dedicated surface functionalization protocols have been developed, using different functional groups for ligand immobilization. Finally, conjugated polymer nanoparticles have recently also been employed for theranostic applications, wherein the particles are simultaneously used as fluorescent probes and carriers for anti-tumor drugs.