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Dopamine was self-polymerized onto the surface of a glassy carbon electrode (GCE), and the obtained polydopamine (PDOA) functioned as a scaffold for the grafting of half-polyamidoamine (H-PAMAM) dendrimers, which is a new class of polymeric biomaterial as drug carriers. Aspirin was chosen as the model drug and loaded into the H-PAMAM dendrimers via ion pairing, hydrogen bonding and hydrophobic interaction. The synthesis of H-PAMAM dendrimers grafted PDOA was characterized by electrochemical impedance spectroscopy (EIS), attenuated total reflection infrared spectroscopy (ATR-IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), UV-visible spectroscopy and water contact measurement. The process of aspirin loading and delivery was also monitored by EIS. The results demonstrate that PDOA films can be used as an excellent platform for grafting of H-PAMAM dendrimers, which is an ideal carrier for drug loading and delivery.The past years have witnessed the development of polyamidoamine (PAMAM) dendrimers as drug-delivery system because of their exceptional structure and properties such as abundance of internal cavities, amino (full-generation) or ester (half-generation) terminated functional groups, and attractive biocompability. 1-4 Leng et al. 5 synthesized PAMAM dendrimer conjugated chitosan nanoparticles for the delivery of methotrexate, improving the efficiency and reducing the side effects of methotrexate. Zhou et al. 6 prepared a linear-dendritic copolymer based on PAMAM for a greater enhancement in the solubility and drug-loading efficiency for an anti-cancer drug paclitaxel. More recently, a PEGylated PAMAM dendrimer-doxorubicin conjugate-hybridized Au nanorod for combined photothermal-chemotherapy was developed, and the obtained biomaterial is pH-sensitive and can release doxorubicin at weak acidic pH value. 7 Since the self-polymerization of dopamine to form surfaceadherent polydopamine (PDOA) to the surface of virtually all inorganic and organic materials was reported by Lee et al., 8 deposition of PDOA films on various materials is extensively adopted for a wide variety of functional uses. 9-13 Recently, novel drug-delivery systems based on PDOA 14 and its composites 15,16 have been developed, showing the promising applications of PDOA in pharmaceutical industry. Moreover, it is noteworthy that PDOA has a high density of anchoring sites (amino and imino groups), providing a versatile platform for consecutive chain-formation reactions (Michael addition reaction and amidation reaction). So the construction of drug-delivery systems based on PDOA core PAMAM dendrimers is a challenging task in pharmaceutical industry.Herein, a novel drug-delivery platform based on PDOA core PAMAM dendrimers was developed, in which the adherent PDOA films were formed by the self-polymerization of dopamine on the surface of a glassy carbon electrode (GCE). Unlike traditional PAMAM dendrimers synthesized using ethylenediamine core, 17,18 microscopy (TEM), UV-visible spectroscopy and water contact measurement w...

Biocompatible and three-dimensional hybrid of salicylic acid (SA)-doped polypyrrole (PPy) and alginate (Alg) was synthesized and employed as a dual-stimuli responsive drug delivery platform. The PPy-Alg hybrid combined the electro-responsive feature of PPy and pH-sensitive feature of Alg. Releasing behaviors of the hybrid using SA as the model drug were investigated at different applied potentials and pHs. Finally, two commonly used mathematical models, Higuchi and Korsmeyer-Peppas model, were employed to understand the release kinetics, respectively, demonstrating that the release is controlled by Fickian diffusion.