A versatile approach for the preparation of micrometer-sized, monodisperse, "mushroom-like" Janus polymer particles in aqueous dispersed systems is proposed. The synthetic methodology of the Janus particles consists of the following two steps. The first step is the preparation of spherical poly(methyl methacrylate) (PMMA)/poly(styrene-2-(2-bromoisobutyryloxy)ethyl methacrylate) (P(S-BIEM)) Janus particles based on the internal phase separation induced by solvent evaporation from the solvent droplets dissolving the polymers. The second step is surface-initiated atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DM) using the Janus particles with ATRP initiator groups at one side of the surface as macroinitiator. As a consequence, mushroom-like PMMA/P(S-BIEM)-graft-poly(DM) Janus particles were prepared, which had pH-responsive property.

Protein corona formation was regulated on the surface in vivo by molecular imprinting to enable polymeric nanogels to acquire stealth upon intravenous administration. Albumin, the most abundant protein in blood, was selected as a distinct protein component of protein corona for preparing molecularly imprinted nanogels (MIP-NGs) to form an albumin-rich protein corona. Intravital fluorescence resonance energy transfer imaging of rhodamine-labeled albumin and fluorescein-conjugated MIP-NGs showed that albumin was captured by MIP-NGs immediately after injection, forming an albumin-rich protein corona. MIP-NGs circulated in the blood longer than those of non-albumin-imprinted nanogels, with almost no retention in liver tissue. MIP-NGs also passively accumulated in tumor tissue. These data suggest that this strategy, based on regulation of the protein corona in vivo, may significantly influence the development of drug nanocarriers for cancer therapy.

Micrometer-sized, monodisperse, "mushroom-like" Janus poly(methyl methacrylate)/poly(styrene-2-(2-bromoisobutyryloxy)ethyl methacrylate)-graft-poly(2-(dimethyl amino)ethyl methacrylate) (PMMA/P(S-BIEM)-g-PDM) particles were successfully synthesized by site-selective surface-initiated activator generated by electron transfer for atom transfer radical polymerization in aqueous dispersed systems with spherical PMMA/P(S-BIEM) composite particles having controlled morphologies prepared using the solvent evaporation method. The anisotropic nonspherical shape of the obtained particles was controlled by changing the percentage of the surface area occupied by localized initiation sites (bromine group) at the surface of the PMMA/P(S-BIEM) composite particles with different P(S-BIEM) contents. Grafted PDM layer formed at the surface (contacting with water) of the P(S-BIEM) phase reversibly exhibited the volume phase transition in response to temperature and pH, which gave different nonspherical shapes ("open" or "closed" mushroom-cap). On the basis of such dual stimuli-responsive properties, the nonspherical particles effectively operated as particulate surfactant for Pickering emulsion, resulting in a stable 1-octanol-in-water emulsion at optimum temperature and pH value, and the Pickering emulsion could be easily unstabilized quickly by controlling them.

Organotellurium-mediated living radical polymerization (TERP) of n-butyl acrylate (BA) in emulsifier-free emulsion polymerization system was carried out for the first time, using the in situ nucleation technique via self-assembly of the propagating amphiphilic polymer chains derived from water-soluble TERP agent, poly(methacrylic acid)-methyltellanyl, with water-soluble thermal initiator, 4,4′-azobis(4-cyanovaleric acid), as a radical source at 60 °C. The polymerization proceeded with high control/livingness to high conversion without coagulation, resulting in nanosized poly(BA) particles. The difference in the stirring rates of the polymerization system, where the whole monomer dispersed as droplets at a high rate or it existed as an upper layer on the aqueous medium at a low rate, had a great influence both on the rate of polymerization and on the degree of the control/livingness. On both of them, the polymerization with the high stirring rate gave more desirable results than those with the low rate. † Part CCCXXII of the series "Studies on Suspension and Emulsion".

Small extracellular vesicles (sEVs) are reliable biomarkers for early cancer detection; however, conventional detection methods such as immune-based assays and microRNA analyses are not very sensitive and require sample pretreatments and long analysis time. Here, we developed a molecular imprintingbased dynamic molding approach to fabricate antibody-conjugated signaling nanocavities capable of size recognition. This enabled the establishment of an easy-to-use, rapid, sensitive, pretreatment-free, and noninvasive sEV detection platform for efficient sEV detection-based cancer diagnosis. An apparent dissociation constant was estimated to be 2.4 × 10 −16 M, which was ∼1000 times higher than that of commercial immunoassays (analysis time, 5 min/sample). We successfully used tears for the first time to detect cancer-related intact sEVs, clearly differentiating between healthy donors and breast cancer patients, as well as between samples collected before and after total mastectomy. Our nanoprocessing strategy can be easily repurposed for the specific detection of other types of cancer by changing the conjugated antibodies, thereby facilitating the establishment of liquid biopsy for early cancer diagnosis.