# Synthesis and Application in Cell Imaging of
## 1 Introduction  
Acridone is a well-known core structure in natural products, the derivatives of which are observed in various pharmacological applications [1; 2]. Many as-such acridone derivatives are extracted due to their use as natural drug efficacy. Glyfoline derived from _Glycosmis citrifolia_ was found to be a potent antineoplastic drug due to the inhibition of nucleoside transport function and injury of the G2/M phase of the tumor cells [3; 4]. Acronymcine, a natural acridone alkaloid isolated from _Acronymchia baueri_, has significant anticancer activities as a result of its interference in DNA replication of tumor cells [5; 6]. A potent anticancer drug, C1311, which is in progress in clinical trials, can bind tumor DNA to inhibit the proliferation of cancer cells [7]. Moreover, several artificial acridone derivatives have acquired the antibacterial and anticancer abilities by incorporating an alkyl chain onto the N-position, such as with pyrimidocarvazones or pyrimidoacridone, respectively [8; 9]. Studies on acridone derivatives shows promising efficacy towards the development of potent anticancer drugs.  
Acridone has an electron-deficient aromatic scaffold, which incorporates a \(\pi\)-conjugated electron donor to form a donor-acceptor chromophore [10]. Based on such tricyclic scaffolds that are susceptible to chemical modification, acridone derivatives have a range of versatile bioactivities and unique optical properties. Moreover, fluorescence from this organic molecule is normally quenched under aqueous conditions. This is due to the natural aggregation of the intrinsic hydrophobic aromatic structures that leads to an aggregation-caused quenching [11]. Given that an adaptable fluorophore normally incorporates various ionic groups, the issues to be addressed are that most donor-acceptor chromophores quench their fluorescence due to the intramolecular charge transfer (ICT) or twisted intramolecular charge transfer (TICT) in aqueous solvents [12; 13; 14]. Fluorophores exhibit aggregation-induced emission (AIE) depending on their particular structures [15; 16; 17]. Unlike chromophores with ICT or TICT above, the AIE luminogens (AIEgens) reveal brilliant fluorescence in aqueous conditions [18; 19]. Recently, the AIEgens have been extensively studied and applied in cellular imaging and various biomedical applications, such as organic molecular frameworks, photosensitive liposomes, AIEgen-encapsulated nanoparticles, and image-guided drug delivery systems [20; 21; 22; 23]. Thus, the adaptable acridone could be properly designed to form an AIEgen in cellular imaging.  
In this study, we prepared two acridone derivatives designed with a surfactant-like acridone scaffold, enabling an auto-assembly in aqueous media. The N10 position was incorporated with a dodecyl group or dodecylpiperidine, respectively. Subsequently, both the two compounds incorporated two 4-vinylpyridines into the 2,7-position via a Heck coupling reaction and methylation. These decorated piperidines serve as electron acceptors and rotational moieties in TICT processes. We observed the unique optical properties owing to the AIE phenomenon which in turn restricts TICT, selectively retrieving fluorescence emission in cellular imaging. Therefore, these surfactant-like acridone derivatives prove to be potential candidates in the development of fluorescence probes and demonstrate usage in various bioapplications.