Active targeting and precise control of drug release based on nanoparticle therapies are urgently required to precisely treat cancer. We have custom-synthesized a functional lipid (termed Fa-ONB) by introducing a folic acid-targeting group into an o-nitro-benzyl ester lipid. As designed, the liposomes formed by Fa-ONB combine active targeting and dual trigger release capabilities, which help to improve drug efficacy and reduce the toxicity of traditional liposomes. We first verified that both pH-induced hydrolysis and light treatment were able to cleave the Fa-ONB lipid. We then prepared a series of liposomes (termed FOBD liposomes) by compounding the Fa-ONB lipid with DOPC at different ratios. After encapsulation of doxorubicin (DOX), we found that the particle size of DOX-loaded FOBD liposomes (DOX/FOBD) first increased (290 to 700 nm) and then decreased again (to 400 nm) under continuous UV irradiation (120 min). The photocatalytic release efficiency under different pH conditions was investigated by dialysis experiments, and it was found that the release efficiency in an acidic environment was significantly increased relative to neutral pH. This pH-triggered release response helps distinguish pathological tissues such as lysosomal compartments and tumors. The light-induced formation of a DOX precipitate increases in efficiency with increasing UV exposure time as well as with increasing environmental acidity or alkalinity. In addition, confocal imaging and flow cytometry showed that the ability of FOBD lipids to actively target HeLa cells increased with increasing Fa-ONB lipid content. Real-time in vivo fluorescence small animal experiments proved targeting to tumors and pH-and photoinduced release properties. Furthermore, therapeutic experiments using a mouse model found a significant tumor inhibitory effect for DOX/FOBD55 liposomes with UV irradiation, clearly demonstrating the benefit of light treatment: the tumor size of the control (PBS) group was 7.59 times that of the light treatment group. Therefore, this research demonstrates the benefits of combining triggerable release functions and effective active tumor targeting in one small lipid molecule for precise cancer treatment.
Although chemodynamic therapy (CDT) can effectively inhibit tumor growth and metastasis, it is challenging to eliminate tumors. Generally, CDT needs to combine with extra therapeutic modes for enhancing antitumor efficacy. Here, novel nanoparticles (BDTLAG NPs) are constructed via self‐assembly of cancer cell targeting prodrug (Bio‐PEG2K‐S‐S‐CPT), organic CDT agents (TPP‐PEG2K‐LND, TPP‐PEG2K‐TOS), pH‐responsive prodrug (PEG2K‐NH‐N‐DOX), T1‐enhanced magnetic resonance imaging contrast agents (Gd‐DTPA‐N16‐16), and anti‐angiogenic drug combrestatinA4 (CA4), realizing chemo(CT)‐chemodynamic combination therapy. The mechanism of BDTLAG NPs for enhancing antitumor efficacy involves: (i) BDTLAG NPs is accumulated in the tumor tissue by passive targeting; (ii) CA4 is released and specifically destroys angiogenesis, and the remaining BDTLG NPs enter the tumor cell via active targeting; (iii) the acid/glutathione (GSH)‐responsive prodrug release and GSH depletion; (iv) TPP‐PEG2K‐LND and TPP‐PEG2K‐TOS are accumulated in the tumor cell mitochondria due to mitochondria‐targeting, and is accompanied by endogenous reactive oxygen species bursts. This current strategy of single NPs that integrates spatiotemporally CT, CDT, GSH depletion, and MR imaging functions reflects the “all in one” concept, which provides a new opportunity for enhancing antitumor efficacy.
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