Electron Donor–Acceptor Effect-Induced Organic/Inorganic Nanohybrids with Low Energy Gap for Highly Efficient Photothermal Therapy

Abstract

For the design and optimization of near-infrared photothermal nanohybrids, tailoring the energy gap of nanohybrids plays a crucial role in attaining a satisfactory photothermal therapeutic efficacy for cancer and remains a challenge. Herein, we report an electron donor−acceptor effect-induced organic/ inorganic nanohybrid with a low energy gap (denoted as ICG/Ag/ LDH) by the in situ deposition of Ag nanoparticles onto the CoAl−LDH surface, followed by the coupling of ICG. A combination study verifies that the supported Ag nanoparticles as the electron donor (D) push electrons into the conjugated system of ICG by the electronic interaction between ICG and Ag, while OH groups of LDHs as the electron acceptor (A) pull electrons from the conjugated system of ICG by hydrogen bonding (N•••H−O). This induces the formation of the D−A conjugated π-system and has a strong influence on the π-conjugated system of ICG, thus leading to a prominent decrease toward the energy gap and correspondingly an ultra-long redshift (∼115 nm). The resulting ICG/Ag/LDHs show an enhanced photothermal conversion efficiency (∼45.5%) at 808 nm laser exposure, which is ∼1.6 times larger than that of ICG (∼28.4%). Such a high photothermal performance is attributed to the fact that ICG/Ag/LDHs possess a D−π−A hybrid structure and a resulting lower energy gap, thus effectively promoting nonradiative transitions and leading to enhancement of the photothermal effect. Both in vitro and in vivo results confirm the good biocompatible properties and capability of the ICG/Ag/LDHs for NIR-triggered cancer treatment. This research demonstrates a successful paradigm for the rational design and preparation of new nanohybrids through the modulation of electron donor−acceptor effect, which offers a new avenue to achieve efficient phototherapeutic agent for improving the cancer therapeutic outcomes.

Engineering Self-Assembled Nanomedicines Composed of Clinically Approved Medicines for Enhanced Tumor Nanotherapy

“…To improve the availability and relieve the side effects, a facile self-assembly method via the interaction between the hydrophobic molecules and amphipathic molecules is developed in this study. ICG, an amphipathic fluorescent dye, has been proved to be one kind of typical agent for PTT due to its desirable absorption at the near-infrared (NIR) [ 39 , 40 ], which has been approved by the FDA. However, free ICG has critical issues such as rapid elimination because of its small molecular size.…”

Construction of an Injectable Composite Double-Network Hydrogel as a Liquid Embolic Agent

“…For this objective, the injectable CDN hydrogel composed of a benzaldehyde-capped poly­(ethyl glycol) cross-linked carboxymethyl chitosan network (denoted as CMC/OHC-PEG-CHO) and a 3-aminophenylboronic acid cross-linked poly­(vinyl alcohol) network (PVA/3-AB) was synthesized through dynamic covalent bonding of benzoic-imine and borate ester, while LDHs were conjugated in the dynamic hydrogel via physical interaction like hydrogen bonding (Scheme ). Besides, it was found that indocyanine green (ICG) could be absorbed by LDHs, − and doxorubicin hydrochloride (DOX) could be embedded into the hydrogel matrix. − In this work, we demonstrated the functionalization of the injectable CDN hydrogel with embedded ICG and DOX for introducing the ability of photothermal therapy (PTT) and photothermal-triggered drug release. We have illustrated that the injectable CDN hydrogel is capable of embolizing the renal artery and can efficiently inhibit the subcutaneous tumor growth through the combination of PTT and chemotherapy on animal models.…”