Lyophilized mRNA-lipid nanoparticles vaccine with long-term stability and high antigenicity against SARS-CoV-2

Advanced mRNA vaccines play vital roles against SARS-CoV-2. However, due to their poor stability, most current mRNA delivery platforms need to be stored at -20{degrees}C or -70{degrees}C, which severely limits their distribution. Herein, we present lyophilized SARS-CoV-2 mRNA-lipid nanoparticle vaccines, which can be stored at room temperature with long-term thermostability. In the in vivo Delta virus challenge experiment, lyophilized Delta variant mRNA vaccine successfully protected mice from infection and cleared the virus. Lyophilized omicron mRNA vaccine enabled to elicit both potent humoral and cellular immunity. In booster immunization experiments in mice and old monkeys, lyophilized omicron mRNA vaccine could effectively increase the titers of neutralizing antibodies against wild-type coronavirus and omicron variants. In humans, lyophilized omicron mRNA vaccine as a booster shot could also engender excellent immunity and had less severe adverse events. This lyophilization platform overcomes the instability of mRNA vaccines without affecting their bioactivity, and significantly improved their accessibility, particularly in remote regions.

Extension and dentin differentiation potential of dental pulp stem cells from human deciduous teeth on the stiff matrix surface / 中国组织工程研究

BACKGROUND: Dental pulp stem cells can differentiate into dentin under appropriate induction conditions, which are important seed cells i n dental tissue engineering. However, the commonly used inducers are chemical agents, which are not available for in vivo application. Mesenchymal stem cells can differentiate with the material hardness, and the physical property-induced cell differentiation is little reported. OBJECTIVE: To observe the extension characteristics and dentin differentiation potential of dental pulp stem cells from human deciduous teeth on the stiff matrix surface. METHODS: Dental pulp stem cells from naturally shed deciduous teeth were isolated, cultured and identified. Four solid gel matrixes with elasticity modulus of (9.12±0.94), (27.18±3.55), (59.37±4.05) and (86.45±5.33) kPa were made using low melting point agarose. The extension ability of passage 4 dental pulp stem cells on the surface of the above solid matrixes was detected by two-dimensional clone formation and cell scratch tests. The protein expression levels of dentin matrix protein-1, dentin phosphoprotein and dentin sialoprotein were detected by western blot assay. RESULTS AND CONCLUSION: Dental pulp stem cells from human deciduous teeth seeded on the gel matrix with extremely low and low hardness almost existed as cell clones with neat edges, and cell spreading and extension were rare. When seeded on the gel matrix with moderate and high hardness, the cloned edge of deciduous dental pulp stem cells spread and extended obviously. The cell body became large and the cell edge extended significantly. The cell scratch test revealed the similar phenomenon. When seeded on the gel matrix with moderate and high hardness, dental pulp stem cells from human deciduous teeth exhibited high expression levels of of dentin matrix protein-1, dentin phosphoprotein and dentin sialoprotein. In summary, with the increase of matrix hardness, the abilities of extension and differentiation into dentin of dental pulp stem cells from human deciduous teeth are increased gradually, which provides a method for dental tissue engineering.

Fabrication of valine-functionalized graphene quantum dots and its use as a novel optical probe for sensitive and selective detection of Hg2.

The functionalization of graphene quantum dots has become a powerful method to modulate its chemical, electronic and optical properties for various applications. In the study, we reported a facile synthesis of valine-functionalized graphene quantum dots (Val-GQDs) and its use as a novel fluorescent probe for optical detection of Hg2+. Herein, Val-GQDs was synthesized by the thermal pyrolysis of citric acid and valine. The resulting Val-GQDs has an average size of 3nm and the edge of graphene sheets contains the rich of hydrophilic groups, leading to a high water-solubility. Compared to the GQDs prepared by thermal pyrolysis of citric acid, Val-GQDs exhibits a stronger fluorescence (>10-fold) and better photostability (>4-fold). Interestingly, the existence of valine moieties in the Val-GQDs results in a more sensitive fluorescent response to Hg2+. The fluorescent signal will linearly decrease with the increase of Hg2+ concentration in the range from 0.8nM to 1µM with the correlation coefficient of 0.992. The detection limit is 0.4nM (S/N=3), which the sensitivity is >14-fold that of GQDs. The analytical method provides the prominent advantage of sensitivity, selectivity and stability. It has been successfully applied in the optical detection of Hg2+ in real water samples. The study also provides a promising approach for the design and synthesis of functionalized GQDs to meet the needs of further applications in sensing and catalysis.

Pleomorphic hyalinizing vascular tumor of neck soft tissue:Report of 1 case / 实用口腔医学杂志

1 cases of pleomorphic hyalinizing vascular tumor(PHAT) at the right side of neck soft tissue is reported and related literatures are reviewed.The clinical symptoms of PHAT are mild and non-characteristic,imaging examination and postoperative pathological examination may show specificity of the lesion.It is a kind of soft tissue tumor with malignant tendency.Surgical excision is the main treatment,long-term follow-up is recommended.