Large-pore coralline mesoporous silica microparticles (CMS) were synthesized using the triblock polymer PEG-b-PEO-b-PEG and a hydrothermal method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the coralline morphology of the fabricated materials. The Brunauer–Emmett–Teller (BET) method and the Barrett–Joyner–Halenda (BJH) model confirmed the existence of large pores (20 nm) and of a tremendous specific surface area (663.865 m²·g⁻¹) and pore volume (0.365 cm³·g⁻¹). A novel pH-sensitive multiamine-chain carboxyl-functionalized coralline mesoporous silica material (CMS–(NH)₃–COOH) was obtained via a facile “grafting-to” approach. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) validated the effective interfacial functionalization of CMS with carboxyl and multiamine chains. The encapsulation and release behavior of the dual drug (gefitinib (GB) and doxorubicin (DOX)) was also investigated. It was found that CMS–(NH)₃–COOH allows rapid encapsulation with a high loading capacity of 47.36% for GB and 26.74% for DOX. Furthermore, the release profiles reveal that CMS–(NH)₃–COOH can preferably control the release of DOX and GB. The accumulative release rates of DOX and GB were 32.03% and 13.66%, respectively, at a low pH (pH 5.0), while they reduced to 8.45% and 4.83% at pH 7.4. Moreover, all of the modified silica nanoparticles exhibited a high biocompatibility with a low cytotoxicity. In particular, the cytotoxicity of both of these two drugs was remarkably reduced after being encapsulated. CMS–(NH)₃–COOH@GB@DOX showed tremendously synergistic effects of the dual drug in the antiproliferation and apoptosis of A549 human cancer cells in vitro.

Xanthomonas axonopodis pv. citri (Xac) belongs to the Gram-negative species, causing citrus canker that seriously affects the fruit yield and quality of many rutaceae plants. Herein, we found that compound 2-(butyldisulfanyl) quinazolin-4(3H)-one exhibited remarkable anti-Xac activity in vitro with a half effective concentration (EC₅₀) of 2.6 μg/mL, while the positive controls thiodiazole-copper with 57 μg/mL and bismerthiazol with 68 μg/mL and this compound showed great anti-citrus canker activity in vivo. This active compound also was confirmed to reduce biofilm formation, increase the level of reactive oxygen species, damage the morphological structure of the bacteria, and cause bacterial death. Proteomics and RT-qPCR analysis results indicated that this compound down-regulated the expression of enzymes in the MEP (2-methyl-D-erythritol 4-phosphate) pathway and might achieve destructive ability of Xac. Overall, this study indicates that such derivatives could be a promising scaffold to develop novel bactericides to control citrus canker.

Herein, dual-mesoporous structure silica (with pore sizes from 2 to 4 nm and from 4 to 16 nm) simultaneously modified with amino and carboxyl groups was successfully synthesized. Doxorubicin (DOX) and cisplatin (Pt) were loaded onto the interior of the spherical mesoporous silica carrier material, and the macromolecular model drug bovine serum albumin (BSA) was loaded onto the outer layer using aminoguanidine-cyclodextrin as a blocking agent; moreover, folic acid (FA) was introduced to achieve targeted functionalization. Thus, a multi-drug and protein therapy system was constructed with a targeting functionality and pH stimulation-responsive controlled release system. Drug-loaded testing results showed that the amino and carboxyl-functionalized nanoparticles displayed high degrees of drug loading for DOX, Pt and BSA. The loading rate of BSA reached 33%. In vitro drug release experiments confirmed that this drug carrier system could achieve “zero pre-release”. The cytotoxicity of the dual-drug system was significantly higher than those of the single-load drug delivery systems although it decreased the toxicity of the drug itself towards the HeLa cells. The multi-drug and protein therapy system with targeting functionality showed better synergistic targeted therapeutic effects for HeLa cells. All the experiments show that the combination of multi-drugs and protein is a promising strategy.