Polymeric Nanoparticles as a Self-Adjuvanting Peptide Vaccine Delivery System: The Role of Shape

Antigens incorporated in subunit vaccines are typically poorly immunogenic, so a strong immunostimulant (adjuvant) and/or delivery system is required to boost immunogenicity. In this work, the various functional polymer nanostructures, that is, rods, worms, spheres, and tadpoles are used to develop potent peptide antigen delivery systems. The antigen PADRE-J8 (PJ8), derived from Group A Streptococcus (GAS) M-protein, is either physically mixed or chemically conjugated to polymeric nanoparticles of different shapes. The physical mixture of polymeric nanoparticles and antigen is more effective in inducing antibody production than their chemical conjugates. Moreover, rod-shaped polymeric nanoparticles in physical mixture with PJ8 elicited higher and more opsonic antibody titers than powerful complete Freund's adjuvant (CFA)-adjuvanted antigen. Herein, for the first time it is demonstrated that a) the block copolymer, in nanoparticle form, can act as an immune adjuvant, b) nanoparticle shape plays a crucial role in their immunogenicity, and c) antigen conjugation is not required, nor is antigen encapsulation or absorption.     

Gray-Box Modeling of the Molecular Weight Distribution in a Batch Polymerization Reactor

We introduce a gray-box approach for modeling the molecular weight distribution in step-growth polymerization reactions using the aggregation population balance equation. The approach is based on extracting a data-based kernel function from in-process measurements of the molecular weight distribution. The method is applied to historical data from an industrial batch polymerization reactor. The resulting model is used for decision support in production by predicting the reaction endpoint corresponding to a target molecular weight. The accuracy of the predictions proved to be sufficient for the deployment of the method.     

Composition and functional properties of hemp seed protein isolates from various hemp cultivars

Hemp seed protein isolates (HPI) were extracted from seven commercial hemp cultivars, a Cornell breeding line, and a commercial hemp heart product, and their composition and functional properties were investigated. HPI contained different ratios of edestin, vicilin, and albumin proteins, which affected protein solubility and functionality. Higher protein solubility was associated with cultivars that contained more vicilin and albumin, which influenced the subsequent functional properties of HPI. Significant differences in water holding capacity (0.83–1.05 g water/g protein isolate), oil holding capacity (1.28–1.81 g oil/g protein isolate), foam capacity (52.9%–84.9%), and foam stability (68.1%–89.4%) were observed across HPI. The Cornell hemp breeding line exhibited the highest protein solubility at pH 7.0 and was uniquely capable of forming an emulsion. The relationship identified between hemp seed protein composition and functionality, in conjunction with the demonstration of an on-going hemp breeding line, suggest that continued, targeted development of hemp cultivars can improve its seed protein functional properties for ingredient utilization in plant-based foods.