Cyclodextrin (CD) has great application value in biomedicine, mainly due to its good biocompatibility, high drug-loading rate, and controlled release of drugs. It can be used as a coating polymer on medical devices in biomedical engineering or as a joint filler in tissue engineering [1,2]. In addition, CDs can also be engineered as biomimetic corneal implants for corneal transplantation and form inclusion complexes with chemiluminescence probes to achieve bioimaging. The following highlights the use of CD in biomimetic corneal transplantation and bioimaging in biomedical engineering.
Biomimetic Corneal Transplantation
The ideal treatment for corneal blindness would be to produce biomimetic artificial corneas with sufficient transparency, mechanical resistance, and biocompatibility. CDs have the ability to modulate collagen assembly during vitrification. Therefore, they can aid in the bioengineering of collagen growth in vitro to design transparent and mechanically robust corneal substitutes [2]. These substitutes not only resemble native corneas but are sufficiently resistant and support re-epithelialization and host tissue integration [3,4].
Majumdar and other researchers added β-CD to collagen to modulate collagen assembly and produce materials with aligned fibers and lamellae similar to those of natural cornea. Fig. 1 demonstrates CD-collagen interaction. The self-assembled collagen was converted into the β-CD/collagen implants through engineering custom molds for gelation and vitrification. The CD-based implants demonstrated tissue integration and supported re-epithelialization in a rabbit keratoplasty model, providing a new strategy for designing corneal mimetic substitutes with advanced structural and functional properties [3].
Fig. 1 CDs modulate fibril formation and alignment in vitrified collagen cornea substitutes via interactions with collagen [3].
Bioimaging
Non-invasive acquisition of biomedical images at the tissue and cellular levels has attracted considerable interest. Bioimaging using chemiluminescence is attractive because it does not require an external light source. CDs can encapsulate hydrophobic molecules due to their central cavity structure. Therefore, encapsulating chemiluminescent probes in CDs to form inclusion complexes can significantly enhance the luminescence intensity of probes, making them useful for bioimaging.
Gnaim and other researchers synthesized a 1:1 host-guest complex by encapsulating chemiluminescent phenoxy-adamantyl-1,2-dioxetane probes with trimethylated-β-CD (TMCD), which can significantly enhance the chemiluminescence emission effect of the probe in water. In addition, TMCD-fluorescein isothiocyanate (FITC) was also synthesized, which is a conjugate of fluorescein dye and the TMCD host molecule. Complexation of it with phenoxy 1,2-dioxetane exhibited a remarkably strong chemiluminescence emission signal. As a chemiluminescent probe, this TMCD-FITC-phenoxy 1,2-dioxetane system can be used for producing chemiluminescence images of human embryonic kidney cells transfected with Lac-Z (HEK293-LacZ cells). Fig. 2 illustrates the synthesis of the TMCD-FITC-phenoxy 1,2-dioxetane system as well as the chemiluminescence image of HEK-293-LacZ cells [5].
Fig. 2 (a) Chemical structures of phenoxy 1,2-dioxetane (probe 2) and TMCD-FITC, and (b) the chemiluminescence microscopy image of HEK-293-LacZ cells [5].
Alfa Chemistry is dedicated to the manufacture of CDs. We offer high-quality native CDs, CD derivatives, and CD inclusion complexes. We have strong supply capabilities and can provide products at the kilogram level. Please feel free to contact us and we will serve you wholeheartedly.
References
- Wankar, J.; et al. Recent advances in host–guest self-assembled cyclodextrin carriers: Implications for responsive drug delivery and biomedical engineering. Adv. Funct. Mater. 2020, 1909049.
- Braga, S. S. Cyclodextrins: Emerging Medicines of the New Millennium. Biomolecules. 2019, 9(12): 801.
- Majumdar, S.; et al. Cyclodextrin Modulated Type I Collagen self-assembly to engineer biomimetic cornea implants. Adv. Funct. Mater. 2018, 18040763.
- Chellam, J.; Mandall, A. B. Influence of cyclodextrins on the physical properties of collagen. Int. J. Pharma Bio Sci. 2013, 4: 795–806.
- Gnaim, S.; et al. Light emission enhancement by supramolecular complexation of chemiluminescence probes designed for bioimaging. Chem. Sci. 2019, 10: 2945-2955.
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