PEG‐Polymer Encapsulated Aggregation‐Induced Emission Nanoparticles for Tumor Theranostics

Abstract

In the field of tumor imaging and therapy, the aggregation-caused quenching (ACQ) effect of fluorescent dyes at high concentration is a great challenge. In this regard, the aggregation-induced emission luminogens (AIEgens) show great potential, since AIEgens effectively overcome the ACQ effect and have better fluorescence quantum yield, photobleaching resistance, and photosensitivity. Polyethylene glycol (PEG)-polymer is the most commonly used carrier to prepare nanoparticles (NPs). The advantage of PEGylation is that it can greatly prolong the metabolic half-life and reduce immunogenicity and toxicity. Considering that the hydrophobicity of most AIEgens hinders their application in organisms, the use of PEG-polymer encapsulation is an effective strategy to overcome this obstacle. Importantly, bioactive functional groups can be modified on PEG-polymers to enhance the biological effect of NPs. The combination of powerful AIEgens and PEG-polymers provides a new strategy for tumor imaging and therapy, which is promising for clinical application.

Multiregulation of Aggregation‐Induced Emission (AIE) via a Competitive Host–Guest Recognition and α‐Amylase Hydrolyzing

“…Bile acids, such as CA can form stable host–guest inclusion complex with β ‐ and γ ‐CDs and would be a suitable competitive guest for TPE units. [ 14 ] As shown in Figure 1C,D, after adding the various amounts of competitive guest CA into the complex between TPE‐PEG and γ ‐CD, the multiple peaks from TPE units gradually disappear and become broad again, following the chemical shifts upfield and intensity decreasing with the increased molar ratio of CA to TPE units. Especially when [CA]/[TPE] is 8:1, the 1 H NMR signals of the aromatic rings of TPE moieties basically restored to the initial state in the absence of γ ‐CDs (red rectangle).…”

“…Bile acids, such as CA can form stable host-guest inclusion complex with 𝛽and 𝛾-CDs and would be a suitable competitive guest for TPE units. [14] As shown in The AIE behavior highly depends on the aggregation state of the hydrophobic TPE units, which is related to the balance of hydrophilicity/hydrophobicity of the polymers. [24,44] 𝛾-CDs can form inclusion complexes with TPE units of TPE-PEG as evidenced in Figure 1.…”

“…Furthermore, CA has an appropriate size to form a complex with γ ‐CD. [ 14 ] These characters endow CA a suitable competitive guest. Meanwhile, as a substrate of α ‐amylase, CDs can be hydrolyzed by α ‐amylase via cleaving the α ‐1,4 glycosidic bonds, which provides another stimulus to turn on the fluorescence of CD based AIE host–guest complex.…”

“…[8][9][10] Monitoring the fluorescence of the AIEgens based nanocarriers to obtain information about the biodistribution of delivery systems. [11][12][13][14] Therefore, fluorescence regulation is a source of inspiration for the design of smart materials that dynamically adapt to changing circum. By far, some methods have been developed to adjust fluorescence, such as changing the solubility of AIE molecules, triggering spatial restriction, and combining with other photophysical processes.…”

Effective Triple-Negative Breast Cancer Targeted Treatment Using iRGD-Modified RBC Membrane-Camouflaged Nanoparticles

“…PEG-modified nanoparticles can effectively reduce phagocytosis through the mononuclear phagocyte system (MPS) to achieve long circulation throughout the body. [21][22][23] However, PEG-modified nanoparticles can also stimulate the immune system after multiple administrations, causing subsequent administration of nanoparticles to be recognized and swallowed by the immune system; therefore, immune escape cannot be achieved. 24 In recent years, studies have focused on the new field of biological camouflage nanocarriers, and one of the effective methods is using cell membrane-coated nanoparticles to achieve biological camouflage.…”