Biophysical characterization of polydisperse liposomal adjuvant formulations

Microfluidic development of liposome nanoparticles encapsulated with yam polysaccharide

A novel liposome nanoparticle loaded with yam polysaccharide was developed in this study via a tailor-made microfluidic device and further optimized through the Box-Behnken Design method of surface analysis to exploit combinational immunomodulatory effects of liposomes and yam polysaccharide. A chip of 100 μm in height and 200 μm in width with a mixing channel with embedded baffles to enhance fluid mixing was first designed and fabricated. Liposome nanoparticles were obtained by manipulating the operating parameters of the microfluidic chip. The formulation of yam polysaccharide loaded liposomes (YPL1) was optimized using response-surface analysis, and their physicochemical properties were characterized. In vitro cellular assays were performed to assess the effect of YPL on the activity of mouse dendritic cells (DC) and the secretion of immune-related cytokines to investigate the immune-enhancing effect of YPL in vitro. The resulting YPL had a mean size of 154.2±3.8 nm with a narrow size distribution (PDI=0.083) and had a high entrapment efficiency (EE) of 79.02%. The YPL exhibited good stability at 4°C over 14 days of storage, and an in vitro sustained release duration of approximately 30 h. The YPL demonstrated excellent biocompatibility and stimulated the expression of immune-related cytokines, especially TNF-α. Therefore, the YPL with well controlled particle size and high loading capacity, capable of exhibiting potent immunostimulatory activity was successfully developed in this study via a microfluidic device and optimized using response-surface analysis. The current YPL engineering methodology could further serve as an experimental platform for liposome nanoparticle development.

Biophysical characterization of α-glucan nanoparticles encapsulating feruloylated soy glycerides (FSG)

Water insoluble α-glucans that were enzymatically synthesized using glucansucrase that was cloned from Leuconostoc mesenteroides NRRL B-1118 were previously shown to form nanoparticles via high pressure homogenization. These α-glucan nanoparticles were previously shown capable of encapsulating a small hydrophobic molecule. This work demonstrates that the same α-glucan can be formed into nanoparticles that encapsulate feruloylated soy glycerides from modified soybean oil, a product of interest to the cosmetic and skin care industries because of the UV absorbance and antioxidant properties of the feruloyl moiety. It is demonstrated that the feruloylated soy glyceride/α-glucan nanoparticles have distinct size, zeta potential and thermal profiles from that of nanoparticles made from α-glucan alone or feruloylated soy glyceride alone. Thermal analysis also demonstrates the release of feruloylated soy glycerides from the α-glucan nanoparticles.

Army liposome formulation containing QS-21 render human monocyte-derived macrophages less permissive to HIV-1 infection by upregulating ABOBEC3A

Monocyte-derived macrophages (MDM) are highly permissive to HIV-1 infection potentially due to the downregulation of innate factors during the differentiation process. The environmental milieu and innate anti-viral factors which are modulated during macrophage differentiation, have been associated with their increased permissiveness to HIV-1 infection. Here, we demonstrate that the Army Liposome Formulation containing MPLA, and QS-21 (ALFQ) activated MDM that are normally permissive to HIV-1 infection to generate a proinflammatory environment and upregulated anti-viral factors notably APOBEC3A. Induction of APOBEC3A by ALFQ decreased permissiveness to HIV-1 infection, while knockdown of APOBEC3A with APOBEC3AsiRNA resulted in a significant loss in the restriction of HIV-1 infectivity. The liposome formulation ALF55, with identical lipid composition but lacking QS-21 had no effect. Furthermore, the capacity of ALFQ to modulate MDM permissiveness to HIV-1 infection was predominantly mediated by large ALFQ liposomes. Our findings highlight a relationship between innate immune activation, proinflammatory milieu, and upregulation of anti-HIV proteins. Induction of these responses can switch the HIV-1 permissive MDM into a more refractory phenotype.