One of the major limitations impeding the sensitivity and specificity of biomarker targeted nanoparticles is non-specific binding by biomolecules and uptake by the reticuloendothelial system (RES). We report the development of an antibiofouling polysiloxane containing amphiphilic diblock copolymer, poly(ethylene oxide)-block-poly(γ-methacryloxypropyltrimethoxysilane) (PEO-b-PγMPS), for coating and functionalizing high quality hydrophobic nanocrystals such as iron oxide nanoparticles and quantum dots. These PEOb-PγMPS coated nanocrystals were colloidally stable in biological medium and showed low nonspecific binding by macromolecules after incubation with 100% fetal bovine serum. Both in vitro experiments with macrophages and in vivo biodistribution studies in mice revealed that PEO-b-PγMPS copolymer coated nanocrystals have an antibiofouling effect that reduces non-specific cell and RES uptake. Surface functionalization with amine groups was accomplished through cocrosslinking the polysiloxane coating layer and (3-Aminopropyl) trimethoxysilane in aqueous solution. Tumor integrin α v β 3 targeting peptide cyclo-RGD ligands were conjugated on the nanoparticles through a heterobifunctional linker. The resulting integrin α v β 3 targeting nanoparticle conjugates showed improved cancer cell targeting with a stronger affinity to U87MG glioma cells, which have a high expression of α v β 3 integrins, but minimal binding to MCF-7 (low expression of α v β 3 integrins).

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We report the rational design and implementation of a new class of gel guest-assisted, ionic covalent organic framework (COF) membranes that exhibit superior H+ conduction. The as-synthesized COFs are postmodified via a lithiation (or sodiation) treatment. The hydrophilic Li or Na ions in the COFs form a dense and extensive hydrogen-bonding network of H2O molecules with mobile H+ at the periphery, thereby transforming COFs into H+ conductors. Then, the ionic COFs are assembled into a flexible H+ conductor membrane via a gelation process, where the organic gel provides both mechanical strength and additional H+ carriers for fast H+ conduction. The final COF-based membrane exhibits an excellent H+ conductivity of 1.3 × 10–1 S cm–1 at 313 K and 98% relative humidity, which are the highest values of the COF-based H+ conductors reported until now and are even comparable with those of the typical commercial Nafion membrane. We anticipate that the two-in-one strategy would open up a porous COF-driven new molecular framework and membrane architectural design/opportunity for development of next-generation ionic conductors.

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