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For polymer particles, recent studies emphasized that the particle shape—not size—plays the dominant role in novel applications in fields ranging from nanotechnology, biomedicine, to photonics, which has intensified the quest for fabrication platforms of polymer colloids with complex non-spherical (anisotropic) shapes. Here, we developed a single-step, microfluidic-supported synthesis for anisotropic polyvinyl methacrylate (PVMA) nanoparticles (NPs) by combining the advantages of microfluidics (providing homogeneous conditions for the initial emulsification process) and bulk batch synthesis (providing inhomogenous conditions for the thermal polymerization). Specifically, we tested five interfacial agents regarding their direct impact on the NP shape (from isotropic spherical to anisotropic flower-like shapes) and their concentration-dependent impact (from 0.1 mM to 20 mM) on the NP diameter (from 200 nm to 50 nm). We employed vinyl methacrylate (VMA), a monomer offering two-polymerization active sites. With our work, we contribute to a fundamental understanding of colloidal polymerization towards predictive shapes below the critical 200 nm regime. 

An effective vaccine that can protect against HIV infection does not exist. A major reason why a vaccine is not available is the high mutability of the virus, which enables it to evolve mutations that can evade human immune responses. This challenge is exacerbated by the ability of the virus to evolve compensatory mutations that can partially restore the fitness cost of immune-evading mutations. Based on the fitness landscapes of HIV proteins that account for the effects of coupled mutations, we designed a single long peptide immunogen comprising parts of the HIV proteome wherein mutations are likely to be deleterious regardless of the sequence of the rest of the viral protein. This immunogen was then stably expressed in adenovirus vectors that are currently in clinical development. Macaques immunized with these vaccine constructs exhibited T-cell responses that were comparable in magnitude to animals immunized with adenovirus vectors with whole HIV protein inserts. Moreover, the T-cell responses in immunized macaques strongly targeted regions contained in our immunogen. These results suggest that further studies aimed toward using our vaccine construct for HIV prophylaxis and cure are warranted.