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Mucosal delivery systems have gained much attention as effective way for antigen delivery that induces both systemic and mucosal immunity. However, mucosal vaccination faces the challenges of mucus barrier and effective antigen uptake and presentation. In particular, split, subunit and recombinant protein vaccines that do not have an intact pathogen structure lack the efficiency to stimulate mucosal immunity. In this study, poly (lactic acid-co-glycolic acid-polyethylene glycol) (PLGA-PEG) block copolymers were modified by mannose to form a PLGA-PEG-Man conjugate (mannose modified PLGA-PEG), which were characterized. The novel nanoparticles (NPs) prepared with this material had a particle size of about 150 nm and a zeta potential of −15 mV, and possessed ideal mucus permeability, immune cell targeting, stability and low toxicity. Finally, PLGA-PEG-Man nanoparticles (PLGA-PEG-Man NPs) were successfully applied for intranasal delivery of split influenza vaccine in rat for the first time, which triggered strong systemic and mucosal immune responses. These studies suggest that PLGA-PEG-Man NPs could function as competitive potential nano-adjuvants to address the challenge of inefficient mucosal delivery of non-allopathogenic antigens. [ABSTRACT FROM AUTHOR]

AbstractMicroneedles, as a new efficient and safe transdermal drug delivery technology, has a wide range of applications in drug delivery, vaccination, medical cosmetology, and diagnostics. The degree of microneedles penetration into the skin determines the reliability of the delivery dose, but its evaluation is not yet well-established, which is one of the major constraints in the commercialization of microneedles. In this paper, a novel visual simulated skin model was developed with reference to the physical properties of real skin. The simulated skin model was well-designed and its prescription was optimized to make the thickness, hardness, elasticity, and other parameters close to those of real skin. It not only meets the need to assess the degree of insertion of microneedles but also provides a visual observation of the insertion state of microneedles. [ABSTRACT FROM AUTHOR]

Objective: To study the in vitro degradation of oxidized regenerated cellulose absorbable hemostatic products., Methods: The morphology of the oxidized regenerated cellulose hemostatic products before and after degradation was observed by FTIR and SEM. The degradation products were determined by GPC and HILIC-ELSD., Results: In the initial stage of degradation, there was a great change in morphology. GPC determined its degradation end point was 10 d; it was determined that its degradation products contained glucose (0.13%) and cellobiose (0.17%) and other components., Conclusions: A method was established for determining the end point of degradation of oxidized regenerated cellulose, which provided a new idea and reference for the study of the degradation end point.

To develop a method for determining complete degradation time of solublehemostatic products in vitro with accuracy, high speed and effectiveness, the current weight loss method originated from GB/T 16886 serial standards was optimized by using dialysis bag combined with assay of reducing sugar. The degradation was carried out with 3% hydrogen peroxide solution, at 37℃, 150 rpm. The dialysis bags were taken out in the 3rd, 6th, 8th, 10th and 14th day, vacuum drying folowed by percentage of weight loss testing. Cumulative content of reducing sugar in degradation solution out of dialysis bag was determined simultaneously. The correlation analysis was performed by SPSS 22.0 equipped with Pearson Correlation Coeffi cient. The correlation coeffi cient between percentage of weight loss and cumulative content of reducing sugar was 0.957, which ilustrated high correlation with each other. Hence dialysis bag combined with assay of reducing sugar is capable of evaluating the degradation endpoint of soluble hemostatic products in vitro. The method also provides a way for the evaluation of degradation of other degradable biomaterials in vitro.