Self-Assembling Sulfated Lactobacillus Exopolysaccharide Nanoparticles as Adjuvants for SARS-CoV-2 Subunit Vaccine Elicit Potent Humoral and Cellular Immune Responses.

Coronavirus disease 2019 (COVID-19) has caused a global pandemic since its onset in 2019, and the development of effective vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to induce potent and long-lasting immunity remains a priority. Herein, we prepared two Lactobacillus exopolysaccharide (EPS) nanoparticle adjuvants (NPs 7-4 and NPs 8-2) that were constructed by using sulfation-modified EPS and quaternization-modified chitosan. These two NPs displayed a spherical morphology with sizes of 39 and 47 nm. Furthermore, the zeta potentials of NPs 7-4 and NPs 8-2 were 50.40 and 44.40 mV, respectively. In vitro assays demonstrated that NPs could effectively adsorb antigenic proteins and exhibited a sustained release effect. Mouse immunization tests showed that the NPs induced the expression of cytokines and chemokines at the injection site and promoted the uptake of antigenic proteins by macrophages. Mechanically, the NPs upregulated the expression of pattern recognition receptors (toll-like receptors and nod-like receptors) and activated the immune response of T cells and the production of neutralizing antibodies. In addition, the NP adjuvants had favorable immune-enhancing effects in cats, which are of great significance for controlling the trans-host transmission and re-endemicity of SARS-CoV-2. Overall, we demonstrated that NP-adjuvanted SARS-CoV-2 receptor binding domain proteins could induce robust specific humoral and cellular immunity.

Optimized extraction of polysaccharide from Pinus elliottii: Characterization, antioxidant, and moisture-preserving activities.

The study on the extraction conditions, purification, and biological activity of slash pine (Pinus elliottii.) is important for the development of slash pine resources. The optimal process conditions for the extraction of slash pine polysaccharide (SPP) were determined, resulting in a liquid-solid ratio of 66.94 mL/g, extraction temperature of 83.74 °C and extraction time of 2.56 h by using the response surface methodology, and the yield of SPP was 5.99% under the optimized conditions. Following the purification of SPP, the SPP-2 component was obtained and its physicochemical properties, functional group composition, antioxidant capacity, and moisturizing capacity were determined. Structural analysis suggested that SPP-2 has a molecular weight of 118.407 kDa, and was composed of rhamnose, arabinose, fucose, xylose, mannose, glucose, and galactose in a ratio of 5.98: 14.34: 1: 1.75: 13.50: 3.43: 15.79. The antioxidant activity analysis showed that SPP-2 has good free radical scavenging activity, and it was also found to have in vitro moisturizing activity and low irritation. These results suggest that SPP-2 has the potential for applications in the pharmaceutical, food, and cosmetic industries.

Engineered extracellular vesicles and their mimics in cardiovascular diseases.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Current pharmacological interventions for the CVDs suffer from low bioavailability, low retention rate, poor targeting, drug resistance complicated side effects. Extracellular vesicles (EVs), which are lipid vesicles secreted by cells, play key roles in pathological processes of CVDs. Engineered EVs and EV mimics with superior properties can overcome limitations of traditional medicine, thus emerging as alternative therapeutic options for the CVDs. In this Review, we summarized basic concepts of EVs and EV mimics, highlighted engineering strategies, and lastly discussed applications of engineered EVs and EV mimics against the CVDs. We believe this Review can provide some new insights on engineering EVs and EV mimics and facilitate their application in precise control of CVDs.

Universal Antifouling and Photothermal Antibacterial Surfaces Based on Multifunctional Metal-Phenolic Networks for Prevention of Biofilm Formation.

Biofilms formed from the pathogenic bacteria that attach to the surfaces of biomedical devices and implantable materials result in various persistent and chronic bacterial infections, posing serious threats to human health. Compared to the elimination of matured biofilms, prevention of the formation of biofilms is expected to be a more effective way for the treatment of biofilm-associated infections. Herein, we develop a facile method for endowing diverse substrates with long-term antibiofilm property by deposition of a hybrid film composed of tannic acid/Cu ion (TA/Cu) complex and poly(ethylene glycol) (PEG). In this system, the TA/Cu complex acts as a multifunctional building block with three different roles: (i) as a versatile "glue" with universal adherent property for substrate modification, (ii) as a photothermal biocidal agent for bacterial elimination under irradiation of near-infrared (NIR) laser, and (iii) as a potent linker for immobilization of PEG with inherent antifouling property to inhibit adhesion and accumulation of bacteria. The resulted hybrid film shows negligible cytotoxicity and good histocompatibility and could prevent biofilm formation for at least 15 days in vitro and suppress bacterial infection in vivo, showing great potential for practical applications to solve the biofilm-associated problems of biomedical materials and devices.

UV-fluorescence probe for detection Ni2+ with colorimetric/spectral dual-mode analysis method and its practical application.

Fluorescence probe combines with fluorescence imaging technology has become the most powerful analytical method with their great advantages of high sensitivity and selectivity and real-time monitoring. Ni2+ is widely distributed in food, environment and living animals, thereof, it is of great significance for detection Ni2+ with high selectivity. Herein, a simple strategy is proposed to design and synthesiz a small molecule fluorescent probe Y1 by using "one-pot" method. The spectroscopic behaviors including UV-Vis absorption and fluorescence emission spectrum have been used to verify the feasibility of probe towards Ni2+ in water/EtOH (v/v = 2:8) mixtures under neutral condition. As expected, Y1 offers high selectivity and sensitivity for detection Ni2+ in aqueous solution with a good linear relationship and low detection limit within Ni2+ concentration variation from 0 to 13 µM (DOL = 0.0038 µM, R2 = 0.9983). It is remarkable that Y1 can be applied for real-time visualization Ni2+ change in sprouted potato and zebrafish with great photo-stability, highlighting that the practicability and feasibility of Y1 to detect and monitor Ni2+ in the field of food industry and biomedical field.