The faster uptake of LPK++ NPs may be due to the

electrostatic attraction between the positive surface charges on LPK ++ and the negative charges on the plasma membrane of DCs. Figure 5 Flow cytometry measurement of uptake of PK NPs and LPK NPs by JAWSII DCs. One milligram of NPs was incubated with 106 cells for 1, 2, and 3 h, respectively. As time lapsed, more NPs were ingested by cells. Enhanced uptake of LPK NPs by DCs was observed compared to PK NPs. DCs are more readily to uptake positively charged NPs compared www.selleckchem.com/products/AZD7762.html to negatively charged NPs. Most of the cells (>90%) had taken up LPK NPs in 3 h, while only 52% of the cells had taken up PK NPs. Figure 6 Confocal images of internalization of PK NPs and LPK NPs by JAWSII DCs. One hundred thousand cells were incubated with 0.1 mg NPs for 1 h (A), 2 h (B), and 3 h (C), respectively. The incubation concentration was 0.2 mg/mL. Red color is from rhodamine B, which was used to label KLH; green color is from NBD PE, which is a fluorescent lipid used to label the lipid layer; and blue color is from CellMask™ Blue Stain, which was used to label the cell membrane. Both positively charged LPK NPs and negatively charged LPK NPs were internalized more readily by cells than PK NPs. Scale bars represent 5 μm. Conclusions In summary, lipid-PLGA hybrid NPs with variable lipid compositions were

constructed. As a potential antigen delivery system, lipid-PLGA Bioactive Compound Library cell assay NPs exhibited superior quality in comparison Glutamate dehydrogenase to PLGA NPs in terms of stability, antigen release, and particle uptake by DCs. The in vitro performance of lipid-PLGA NPs was highly influenced by the composition of the lipid layer, which dictates

the surface chemistry of hybrid NPs. Hybrid NPs enveloped by lipids with more positive surface charges demonstrated higher stability, better controlled release of antigen, and more efficient uptake by DCs than particles with less positive surface charges. The results should provide basis for future design of lipid-PLGA hybrid NPs intended for antigen delivery. Acknowledgements This work was financially supported by the National Institutes of Health, more specifically, the National Institute on Drug Abuse (R21 DA030083). References 1. Grottkau BE, Cai X, Wang J, Yang X, Lin Y: Polymeric nanoparticles for a drug delivery system. Curr Drug Metab 2013, 14:840–846. 10.2174/138920021131400105CrossRef 2. Mallick S, Choi JS: Liposomes: versatile and biocompatible nanovesicles for efficient biomolecules delivery. J Nanosci Nanotechnol 2014, 14:755–765. 10.1166/jnn.2014.9080CrossRef 3. Danhier F, Ansorena E, Silva JM, Coco R, Le Breton A, Preat V: PLGA-based nanoparticles: an overview of biomedical applications. J Control Release 2012, 161:505–522. 10.1016/j.jconrel.2012.01.043CrossRef 4.