Cationic Nanoparticle-Stabilized Vaccine Delivery System for the H9N2 Vaccine to Promote Immune Response in Chickens.

Chinese yam polysaccharides (CYPs) have received wide attention for their immunomodulatory activity. Our previous studies had discovered that the Chinese yam polysaccharide PLGA-stabilized Pickering emulsion (CYP-PPAS) can serve as an efficient adjuvant to trigger powerful humoral and cellular immunity. Recently, positively charged nano-adjuvants are easily taken up by antigen-presenting cells, potentially resulting in lysosomal escape, the promotion of antigen cross-presentation, and the induction of CD8 T-cell response. However, reports on the practical application of cationic Pickering emulsions as adjuvants are very limited. Considering the economic damage and public-health risks caused by the H9N2 influenza virus, it is urgent to develop an effective adjuvant for boosting humoral and cellular immunity against influenza virus infection. Here, we applied polyethyleneimine-modified Chinese yam polysaccharide PLGA nanoparticles as particle stabilizers and squalene as the oil core to fabricate a positively charged nanoparticle-stabilized Pickering emulsion adjuvant system (PEI-CYP-PPAS). The cationic Pickering emulsion of PEI-CYP-PPAS was utilized as an adjuvant for the H9N2 Avian influenza vaccine, and the adjuvant activity was compared with the Pickering emulsion of CYP-PPAS and the commercial adjuvant (aluminum adjuvant). The PEI-CYP-PPAS, with a size of about 1164.66 nm and a ζ potential of 33.23 mV, could increase the H9N2 antigen loading efficiency by 83.99%. After vaccination with Pickering emulsions based on H9N2 vaccines, PEI-CYP-PPAS generated higher HI titers and stronger IgG antibodies than CYP-PPAS and Alum and increased the immune organ index of the spleen and bursa of Fabricius without immune organ injury. Moreover, treatment with PEI-CYP-PPAS/H9N2 induced CD4+ and CD8+ T-cell activation, a high lymphocyte proliferation index, and increased cytokine expression of IL-4, IL-6, and IFN-γ. Thus, compared with the CYP-PPAS and aluminum adjuvant, the cationic nanoparticle-stabilized vaccine delivery system of PEI-CYP-PPAS was an effective adjuvant for H9N2 vaccination to elicit powerful humoral and cellular immune responses.

Experimental study on new structure teeth in a high-temperature environment.

In high-temperature drilling, especially in high-temperature geothermal drilling, cone bits often experience common and severe tooth loss. This issue significantly reduces the cone bit's service life and has a detrimental impact on drilling efficiency. The quality of the fixed teeth plays a crucial role in the performance of the cone bit. In high-temperature environments, conventional methods fail to meet the requirements for securing the cone bit's teeth. Therefore, to address the tooth loss problem in high-temperature drilling, a new tapered tooth structure is proposed. Laboratory experiments were conducted to secure teeth with varying tapers at both normal and high temperatures. The results revealed that the maximum fastening force increased progressively with the degree of taper, reaching its peak at C50. Compared to conventional cylindrical teeth, the maximum fastening force increased by approximately 88.6%-271.1% at different temperatures. The tapered structure demonstrated superior tooth-fixing strength. The maximum fastening force is the smallest at 300 °C, approximately 23.7%-61.2% lower than at normal temperature. Under the same interference conditions, the maximum fastening force increased with greater taper. With interference values of 0.075, 0.095, and 0.115, the maximum fastening force increased by 48.9%-175.1%, 14%-141.6%, and 53%-271.1%, respectively, when compared to cylindrical teeth with C300, C200, C100, and C50 tapers. The tapered structure exhibited superior tooth-fixing strength and significantly enhanced tooth retention strength at high temperatures.

Pickering emulsion stabilized by Chinese Yam polysaccharides PLGA for enhanced humoral and cellular immune responses.

As an important ingredient of Chinese yam, Chinese yam polysaccharides have received wide attention for their remarkable adjuvant activity. Pickering emulsion is an attractive platform for the delivery of vaccines. Our previous study has demonstrated that the Chinese yam polysaccharides PLGA-stabilized Pickering emulsion (CYP-PPAS) is a potentially safe and efficient adjuvant to improve the immune response. In this work, we further investigate the adjuvant activity of CYP-PPAS on cellular immunity. In vitro, the CYP-PPAS increased antigen uptake efficiency by DCs. In vivo, CYP-PPAS triggered the recruitment of DCs and macrophages and subsequently facilitated DCs maturation and antigen migration to lymph nodes. Furthermore, CYP-PPAS induced a robust humoral response and Th1/Th2 immune response, enhanced the activation of CD4+ and CD8+ T lymphocyte subpopulations, and also promoted the activation of cytotoxic T lymphocyte response. As a result, the CYP-PPAS serves as a promising vaccine delivery system to induce robust humoral and cellular immunities against diseases.

Ramulus mori polysaccharide-loaded PLGA nanoparticles and their anti-inflammatory effects in vivo.

In this study, ramulus mori polysaccharide (RMP) was encapsulated into Poly (lactic-co-glycolicacid) (PLGA) to form PLGA-RMP (PR). The aim of study is to investigate anti-inflammatory effects of PR. The particle size of PR nanoparticles was approximately 205.6 ± 1.86 nm. PR nanoparticles showed significant therapeutic effects on colitis mice model, evidenced by attenuation of the loss of body weight, reduction of the DAI score, and restoration of the colon length. From the histopathological analysis, alleviation of the histopathological damage, less production of IFN-γ and IL-6, and improvement of IL-10 were observed with the treatment of PR. Meanwhile, the treatment of PR not only promoted the expression of ZO-1 and occludin, but also improved the contents of acetate, propionate, and butyrate in the colitis colon. Furthermore, PR extenuated the reduction of the diversity and richness of gut microbiota induced by DSS, and decreased the ratio of Firmicutes to Bacteroidetes while increasing the proportion of Clostridium XIVa, Mucispirillum, and Paraprevotella in the gut microbiota. What's more, PR nanoparticles attenuated the metabolic disorders in the colitis colon induced by DSS. These results indicated that PR nanoparticles could serve as a potent nanomedicine to treat IBD and be used as potential prebiotics.

Collagen biomaterial for the treatment of myocardial infarction: an update on cardiac tissue engineering and myocardial regeneration.

Myocardial infarction (MI) remains one of the leading cause of mortality over the world. However, current treatments are more palliative than curative, which only stall the progression of the disease, but not reverse the disease. While stem cells or bioactive molecules therapy is promising, the limited survival and engraftment of bioactive agent due to a hostile environment is a bottleneck for MI treatment. In order to maximize the utility of stem cells and bioactive molecules for myocardial repair and regeneration, various types of biomaterials have been developed. Among them, collagen-based biomaterial is widely utilized for cardiac tissue engineering and regeneration due to its optimal physical and chemical properties. In this review, we summarize the properties of collagen-based biomaterial. Then, we discuss collagen-based biomaterial currently being applied to treat MI alone, or together with stem cells and/or bioactive molecules. Finally, the delivery system of collagen-based biomaterial will also be discussed.