Search Results (5)

Despite recent clinical successes in cancer immunotherapy, it remains difficult to initiate a long-term anti-tumor effect. Therefore, repeated administrations of immune-activating agents are generally required in most cases. Herein, we propose an adjuvant particle size tuning strategy to initiate a long-term anti-tumor effect by one-shot vaccination. This strategy is based on the size-dependent immunostimulation mechanism of mesoporous silica particles. Hollow mesoporous silica (HMS) nanoparticles enhance the antigen uptake with dendritic cells around the immunization site in vivo. In contrast, hierarchically porous silica (HPS) microparticles prolong cancer antigen retention and release in vivo. The size tuning of the mesoporous silica adjuvant prepared by combining both nanoparticles and microparticles demonstrates the immunological properties of both components and has a long-term anti-tumor effect after one-shot vaccination. One-shot vaccination with HMS-HPS-ovalbumin (OVA)-Poly IC (PIC, a TLR3 agonist) increases CD4⁺ T cell, CD8⁺ T cell, and CD86⁺ cell populations in draining lymph nodes even 4 months after vaccination, as well as effector memory CD8⁺ T cell and tumor-specific tetramer⁺CD8⁺ T cell populations in splenocytes. The increases in the numbers of effector memory CD8⁺ T cells and tumor-specific tetramer⁺CD8⁺ T cells indicate that the one-shot vaccination with HMS-HPS-OVA-PIC achieved the longest survival time after a challenge with E.G7-OVA cells among all groups. The size tuning of the mesoporous silica adjuvant shows promise for one-shot vaccination that mimics multiple clinical vaccinations in future cancer immunoadjuvant development. This study may have important implications in the long-term vaccine design of one-shot vaccinations. Full article

Controlling the particle size as well as porosity and shape of silica nanoparticles is always a big challenge while tuning their properties. Here, we designed a cost-effective, novel, green synthetic method for the preparation of perforated hollow mesoporous silica nanoparticles (PHMS-1) using a very minute amount of cationic surfactant in o/w-type (castor oil in water) emulsion at room temperature. The grafting of Al(III) through post-synthetic modification onto this silica framework (PHMS-2, Si/Al ~20 atomic percentage) makes this a very efficient solid acid catalyst for the conversion of monosaccharides to 5-HMF. Brunauer–Emmett–Teller (BET) surface area for the pure silica and Al-doped mesoporous silica nanoparticles (MSNs) were found to be 866 and 660 m²g⁻¹, respectively. Powder XRD, BET and TEM images confirm the mesoporosity of these materials. Again, the perforated hollow morphology was investigated using scanning electron microscopic analysis. Al-doped hollow MSNs were tested for acid catalytic-biomass conversion reactions. Our results show that PHMS-2 has much higher catalytic efficiency than contemporary aluminosilicate frameworks (83.7% of 5-HMF yield in 25 min at 160 °C for fructose under microwave irradiation). Full article

Currently, environmental-responsive pesticide delivery systems have become an essential way to improve the effective utilization of pesticides. In this paper, by using hollow mesoporous silica (HMS) as a nanocarrier and TA-Cu metal–phenolic networks as a capping agent, a pH-responsive controlled release nano-formulation loaded with prochloraz (Pro@HMS-TA-Cu) was constructed. The structure and properties of Pro@HMS-TA-Cu were adequately characterised and analysed. The results showed that the loading content of Pro@HMS-TA-Cu nanoparticles was about 17.7% and the Pro@HMS-TA-Cu nanoparticles exhibited significant pH-responsive properties. After a coating of the TA-Cu metal–phenolic network, the contact angle and adhesion work of Pro@HMS-TA-Cu nanoparticles on the surface of oilseed rape leaves after 360 s were 59.6° and 107.2 mJ·m⁻², respectively, indicating that the prepared nanoparticles possessed excellent adhesion. In addition, the Pro@HMS-TA-Cu nanoparticles demonstrated better antifungal activity against Sclerotinia sclerotiorum and lower toxicity to zebrafish compared to prochloraz technical. Hence, the pH-responsive nanoparticles prepared with a TA-Cu metal–phenolic network as a capping agent are highly efficient and environmentally friendly, providing a new approach for the development of new pesticide delivery systems. Full article

Owing to their good stability and high photothermal conversion efficiency, the development of carbon-based nanoparticles has been intensively investigated, while the limitation of unsatisfactory cellular internalization impedes their further clinical application. Herein, we report a novel strategy for fabrication of Fe₃O₄ yolk–shell mesoporous carbon nanocarriers (Fe₃O₄@hmC) with monodispersity and uniform size, which presented significantly higher cell membrane adsorption and cellular uptake properties in comparison with common solid silica-supported mesoporous carbon nanoparticles with core–shell structure. Moreover, the MRI performance of this novel Fe-based nanoparticle could facilitate precise tumor diagnosis. More importantly, after DOX loading (Fe₃O₄@hmC-DOX), owing to synergistic effect of chemo–phototherapy, this therapeutic agent exhibited predominant tumor cell ablation capability under 808 nm NIR laser irradiation, both in vitro and in vivo. Our work has laid a solid foundation for therapeutics with hollowed carbon shell for solid tumor diagnosis and therapy in clinical trials. Full article

A kind of core-shell hybrid nanoparticle comprised of a hollow mesoporous silica nanoparticles (HMS) core and a copolymer shell bearing N-(3,4-dihydroxyphenethyl) methacrylamide (DMA) and N-isopropylacrylamide (NIPAM) as responsive moieties was prepared. Moreover, the factors that could impact the surface morphology and hierarchical porous structure were discussed. In the presence of Fe³⁺, catechol-Fe³⁺ complexes were formed to achieve pH-responsive polymer shell, combining with thermal-sensitiveness of poly(N-isopropylacrylamide). Doxorubicin (DOX) was applied as a model drug and the behaviors of its loading/release behaviors were investigated to prove the idea. The results exhibited a significant drug loading capacity of 8.6% and embed efficiency of 94.6% under 1 mg ml^–1 DOX/PBS solution. In fact, the loading capacity of drug can be easily improved to as high as 28.0% by increasing the DOX concentration. The vitro cytotoxicity assay also indicated that the as-prepared nanoparticles have no significant cytotoxicity on RAW 264.7 cells. The in vitro experiment showed that the cumulative release of DOX was obviously dependent on the temperature and pH values. This pH/temperature-sensitive hollow mesoporous silica nanosphere is expected to have potential applications in controlled drug release. Full article