We demonstrated a self-assembly of two different kinds of nanoparticles simultaneously directed on a monolayer film of diblock copolymer micelles via physical and chemical arrangements. We first incorporated gold nanoparticles physically around the micelles of a monolayer film of PS-PVP micelles having a short-range hexagonal order. Iron oxide nanoparticles were then synthesized chemically in the PVP core area of the ordered micelles, resulting in a mosaic nanopattern of magnetic iron oxide nanoparticles surrounded by metallic gold nanoparticles. Thus, we were able to direct two kinds of nanoparticles to self-assemble in the specific positions as an example of controlled fabrication of nanometer-sized building blocks.

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The subphase pH effect on the surface micelles of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymers was investigated by the π−A isotherm and the morphology of the Langmuir−Blodgett (LB) film. Ionization of P2VP block significantly affects the π−A isotherm of the surface micelles at the air−water interface. At high pH, where the degree of ionization is low, the π−A isotherm shows a more expanded form and high transition surface pressure reflecting the strong tendency of P2VP blocks spreading on the subphase surface. As the subphase pH is lowered, the transition surface pressure decreases while the transition region is more extended, indicating the facile equilibrium between the flotation and submergence of the P2VP blocks upon surface pressure change. At pH 1.8 at which the 2VP units are completely ionized, the ionized P2VP blocks submerge into the subphase even at low surface pressure, and the transition behavior is not observed. The π−A isotherm behavior can be understood considering the balance of the solubility and the electrostatic repulsion of the ionized P2VP chains. Atomic force microscopy images of the LB films of the PS-b-P2VP surface micelles show isolated circular micelles at high pH. As the subphase pH decreases, the intermicellar distance becomes shorter and the micelles eventually contact each other to form a laced network of circular micelles. The association behavior of surface micelles and the π−A isotherms at low pH are strongly dependent on the ionic strength of the subphase. The linear association of the surface micelles at low pH appears to result from the balance of the hydrophobic attraction among the floated PS cores and the electrostatic repulsion among the submerged P2VP chains. On the other hand, the average aggregation number of each surface micelle is independent of subphase pH, which indicates that the aggregation of the block copolymers to form surface micelles is likely to take place before the P2VP blocks are ionized.

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ObjectivesCurrently, no standardized method is available to predict success rate after percutaneous nephrolithotomy. We devised and validated the Seoul National University Renal Stone Complexity (S-ReSC) scoring system for predicting the stone-free rate after single-tract percutaneous nephrolithotomy (sPCNL).Patients and MethodsThe data of 155 consecutive patients who underwent sPCNL were retrospectively analyzed. Preoperative computed tomography images were reviewed. The S-ReSC score was assigned from 1 to 9 based on the number of sites involved in the renal pelvis (#1), superior and inferior major calyceal groups (#2–3), and anterior and posterior minor calyceal groups of the superior (#4–5), middle (#6–7), and inferior calyx (#8–9). The inter- and intra-observer agreements were accessed using the weighted kappa (κ). The stone-free rate and complication rate were evaluated according to the S-ReSC score. The predictive accuracy of the S-ReSC score was assessed using the area under the receiver operating characteristic curve (AUC).ResultsThe overall SFR was 72.3%. The mean S-ReSC score was 3.15±2.1. The weighted kappas for the inter- and intra-observer agreements were 0.832 and 0.982, respectively. The SFRs in low (1 and 2), medium (3 and 4), and high (5 or higher) S-ReSC scores were 96.0%, 69.0%, and 28.9%, respectively (p<0.001). The predictive accuracy was very high (AUC 0.860). After adjusting for other variables, the S-ReSC score was still a significant predictor of the SFR by multiple logistic regression. The complication rates were increased to low (18.7%), medium (28.6%), and high (34.2%) (p = 0.166).ConclusionsThe S-ReSC scoring system is easy to use and reproducible. This score accurately predicts the stone-free rate after sPCNL. Furthermore, this score represents the complexity of surgery.

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A size distribution of a binary mixture of polystyrene-block-poly(4-vinylpyridine) (PS−P4VP) diblock copolymer micelles was investigated mainly by transmission electron microscopy. A single-layered film of PS−P4VP micelles fabricated by spin-coating enabled a precise measurement of the micellar size. Depending on the mixing protocols, a mixture of pristine small and large micelles or a mixture of pure small micelles and hybridized micelles were formed due to the difference in the kinetics of micelle formation between the copolymers having short and long insoluble P4VP blocks. In addition, the kinetically frozen micelles excluded further evolution of the micelles produced. We also demonstrated feasible creation of an ordered array of copolymer micelles with the mixing protocol which produced nonhybridizing micelles.