Evolution and Competition of Block Copolymer Nanoparticles

Nanoparticle structures formed in a mixture of diblock copolymer and solvent are investigated using a three-phase density functional model and its sharp interface approximation. A wide variety of equilibria described by localized domain patterns are quantified both numerically and analytically. Competition among multiple particles is shown to occur through mass diffusion driven by differences in chemical potential, which may or may not lead to Ostwald ripening behavior. Late stage rigid body dynamics is shown to result from interaction through dipolar fields, leading to orientational alignment and long-range attraction.NSF [DMS-1514689]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Sharp interface limit of an energy modelling nanoparticle-polymer blends

We identify the $\Gamma$-limit of a nanoparticle-polymer model as the number of particles goes to infinity and as the size of the particles and the phase transition thickness of the polymer phases approach zero. The limiting energy consists of two terms: the perimeter of the interface separating the phases and a penalization term related to the density distribution of the infinitely many small nanoparticles. We prove that local minimizers of the limiting energy admit regular phase boundaries and derive necessary conditions of local minimality via the first variation. Finally we discuss possible critical and minimizing patterns in two dimensions and how these patterns vary from global minimizers of the purely local isoperimetric problem.Comment: Minor changes. Rephrased introduction. This version is to appear in Interfaces and Free Boundarie

pH-Degradable mannosylated nanogels for dendritic cell targeting

We report on the design of glycosylated nanogels via core-cross linking of amphiphilic non-water-soluble block copolymers composed of an acetylated glycosylated block and a pentafluorophenyl (PFP) activated ester block prepared by reversible addition fragmentation (RAFT) polymerization. Self-assembly, pH-sensitive core-cross-linking, and removal of remaining PFP esters and protecting groups are achieved in one pot and yield fully hydrated sub-100 nm nanogels. Using cell subsets that exhibit high and low expression of the mannose receptor (MR) under conditions that suppress active endocytosis, we show that mannosylated but not galactosylated nanogels can efficiently target the MR that is expressed on the cell surface of primary dendritic cells (DCs). These nanogels hold promise for immunological applications involving DCs and macrophage subsets

Catalytic polymeric nanoreactors : more than a solid supported catalyst

Polymeric nanostructures can be synthesized where the catalytic motif is covalently attached within the core domain and protected from the environment by a polymeric shell. Such nanoreactors can be easily recycled, and have shown unique properties when catalyzing reactions under pseudohomogeneous conditions. Many examples of how these catalytic nanostructures can act as nanosized reaction vessels have been reported in the literature. This prospective will focus on the exclusive features observed for these catalytic systems and highlight their potential as enzyme mimics, as well as the importance of further studies to unveil their full potential

Reactive precursor particles as synthetic platform for the generation of functional nanoparticles, nanogels, and microgels

Precise control of the chemical functionality of polymer nanoparticles is a key requirement in tailoring their (dynamic) colloidal properties toward advanced applications. However, current synthetic techniques are still limited in the versatility of chemical design and preparation of such functional colloidal nanomaterials. Two major challenges remain: First, various particle preparation methods are restricted in their functional group tolerance, thus hindering certain combinations of polymer backbones with specific functional groups. Second, the preparation of particles with different functionalities requires the synthesis of different particle batches. But this often results in a simultaneous variation of colloidal features. As a result, the accurate determination of important structure–property relations is still hindered. To address these restrictions, postmodification of preformed reactive particles is gaining more attention. This technique has evolved from polymer synthesis, where postpolymerization functionalization enables the introduction of a plethora of functional groups without changing the degree of polymerization and the molecular weight distribution. Similarly, modifying precursor particles enables the introduction of functional groups into particles while reducing variations in colloidal features, e.g., particle size and size distribution. This powerful synthetic method complements established procedures for functionalization of particle surfaces, thereby enabling the facile preparation of (multi‐)functional particle libraries, which will allow precise investigations of structure–property relations

Multifunctional Nanomaterials of DNA Block Copolymers: Synthesis, Self- Assembly, Thermodynamic Studies and Biomedical Applications

Oligonucleotide-conjugated bio-hybrid nanomaterials with a dense DNA layer on the surface have been shown to possess extraordinary selectivity and sensitivity for DNA detection as well as promising results as delivery agents, as demonstrated with the exceptional example of polyvalent oligonucleotide-conjugated gold nanoparticles. However, progress in this field has been slowed, since achieving high DNA density functionalization on the nanoparticle surface for materials other than gold is a major challenge. In this body of work, we have developed a general system to conjugate a dense layer of DNA on the surface of nanoparticles by the self-assembly of DNA block copolymer. These hybrid nanostructures demonstrated enhanced DNA binding, where the DNA strands on the surface of the nanoparticles can recognize and bind to complementary DNA strands without the addition of salt, a condition where free DNA strands do not form duplex. These assemblies are also selective in DNA recognition; they can distinguish different number base mismatches of the complementary DNA. It was determined that these assemblies possess a surface DNA density that is four times higher than that of DNA-conjugated gold nanoparticles of the same size, the highest DNA functionalization reported in the literature in this size range. These assemblies were also effectively taken up by cells without the use of a co-transfecting agent. The high DNA density also protects the degradation of the DNA, making them ideal candidates for DNA delivery and antisensing applications. Lastly, these assemblies have been tested for their antisensing capability, and found that they can effectively down regulate a targeted protein