Near Infrared Light Triggered Cucurbit[7]uril-Stabilized Gold Nanostars as a Supramolecular Nanoplatform for Combination Treatment of Cancer

Abstract

Developing a spatiotemporal-controlled platform with feasible synthesis and multifunctionality is highly desirable in the field of nanomedicine. Here, we present a near-infrared (NIR)-light-triggered approach to control the supramolecular assembly system for drug release and achieve synergistic chemo-photothermal therapy for cancer. A cucurbit[7]uril (CB[7]) stabilized gold nanostar (GNS) platform is designed to encapsulate the anticancer drug camptothecin (CPT) via host-guest chemistry. Importantly, CB[7] behaves not only as a surfactant to improve the stability of GNS in the aqueous solution but also as the cage for intermolecular assembly of CPT molecules. Moreover, without the competitive complexation, the drug release could be stimulated under NIR light irradiation. Synergistic treatment of cancer can be achieved by combining chemotherapy with the photothermal effect of GNS. This work develops a NIR-light-triggered cucurbituril-based drug-release approach that opens the door for remote control of drug release in the supramolecular assembly system.

A near infrared light-triggerable modular formulation for the delivery of small biomolecules

“…The removal of CTAB from the longitudinal facet of the rod is challenging and thus the coverage of AuNRs with CB[ n ] is not trivial [42, 43]. Previous studies have used a surfactant-free wet chemistry with the subsequent formation of gold nanostars instead of well-defined nanorods [13, 43]. However, the synthesis of gold nanostars with CB[ n ] leads to a decrease in the binding strength of the host–guest complex, since one of the macrocycle portals (able to stabilize guest molecules) is attached to the gold nanostar surface [13, 43].…”

“…Previous studies have used a surfactant-free wet chemistry with the subsequent formation of gold nanostars instead of well-defined nanorods [13, 43]. However, the synthesis of gold nanostars with CB[ n ] leads to a decrease in the binding strength of the host–guest complex, since one of the macrocycle portals (able to stabilize guest molecules) is attached to the gold nanostar surface [13, 43]. Therefore, in the current study, we conjugated the macrocycle to a thiol-modified HA followed by the conjugation of the polymeric derivative to the surface of AuNR.…”

“…ligands with low affinity will require low temperature for release, while ligands with high affinity will require high temperatures). During the preparation of the current work, a study has explored host–guest chemistry to release small molecules from nanocarriers upon NIR light activation within cells [13], however, the spatio-temporal controlled release of the drug from the macrocycle upon NIR activation was not demonstrated. In the previous study, the CB [7] was adsorbed to the surface of gold nanostars and thus not chemically conjugated to the surface of the nanocarrier like in the current study.…”

“…By taking advantage of noncovalent interaction between host and guest molecules, supramolecular chemistry has been shown to be a promising approach for the controlled release of drugs [13]. Cucurbit[ n ]urils (CB[ n ]) are a family of macrocycles, with a pumpkin-shaped structure composed of n glycoluril units ( n = 5–8, 10, 14) bridged by methylene groups, which form stable host–guest inclusion complexes with a wide variety of guest molecules [14, 15].…”

Controllable Synthesis and Catalytic Performance of Gold Nanoparticles with Cucurbit[n]urils (n = 5–8)

“…Noble metal nanoparticles with well-defined morphology, composition, and unique physical and chemical properties have already demonstrated their promise in catalysis, sensing, and biomedical applications [1,2,3,4,5]. Although gold and noble metals can be stabilized in different substrates—oxide structures, for example [6,7,8]—these nanoparticles are generally produced from a suitable metal salt in the presence of reducing and stabilizing agents [9,10], which are usually toxic chemicals.…”