Delineation of tumor margins is a critical and challenging objective during brain cancer surgery. A tumor-targeting deep-blue nanoparticle-based visible contrast agent is described, which, for the first time, offers in vivo tumor-specific visible color staining. This technology thus enables color-guided tumor resection in real time, with no need for extra equipment or special lighting conditions. The visual contrast agent consists of polyacrylamide nanoparticles covalently linked to Coomassie Blue molecules (for nonleachable blue color contrast), which are surface-conjugated with polyethylene glycol and F3 peptides for efficient in vivo circulation and tumor targeting, respectively.

We have recently reported that a variety of couplings of nitrogen, sulfur, oxygen, and carbon nucleophiles with organic halides can be achieved under mild conditions (−40 to 30 °C) through the use of light and a copper catalyst. Insight into the various mechanisms by which these reactions proceed may enhance our understanding of chemical reactivity and facilitate the development of new methods. In this report, we apply an array of tools (EPR, NMR, transient absorption, and UV–vis spectroscopy; ESI–MS; X-ray crystallography; DFT calculations; reactivity, stereochemical, and product studies) to investigate the photoinduced, copper-catalyzed coupling of carbazole with alkyl bromides. Our observations are consistent with pathways wherein both an excited state of the copper(I) carbazolide complex ([CuI(carb)2]− ), and an excited state of the nucleophile (Li(carb)), can serve as photoreductants of the alkyl bromide. The catalytically dominant pathway proceeds from the excited state of Li(carb), generating a carbazyl radical and an alkyl radical. The cross-coupling of these radicals is catalyzed by copper via an out-of-cage mechanism in which [CuI(carb)2]− and [CuII(carb)3]− (carb = carbazolide), both of which have been identified under coupling conditions, are key intermediates, and [CuII(carb)3]− serves as the persistent radical that is responsible for predominant cross-coupling. This study underscores the versatility of copper(II) complexes in engaging with radical intermediates that are generated by disparate pathways, en route to targeted bond constructions.

We have recently reported that, in the presence of light and a copper catalyst, nitrogen nucleophiles such as carbazoles and primary amides undergo C–N coupling with alkyl halides under mild conditions. In the present study, we establish that photoinduced, copper-catalyzed alkylation can also be applied to C–C bond formation, specifically, that the cyanation of unactivated secondary alkyl chlorides can be achieved at room temperature to afford nitriles, an important class of target molecules. Thus, in the presence of an inexpensive copper catalyst (CuI; no ligand co-additive) and a readily available light source (UVC compact fluorescent light bulb), a wide array of alkyl halides undergo cyanation in good yield. Our initial mechanistic studies are consistent with the hypothesis that an excited state of [Cu(CN)2]− may play a role, via single electron transfer, in this process. This investigation provides a rare example of a transition metal-catalyzed cyanation of an alkyl halide, as well as the first illustrations of photoinduced, copper-catalyzed alkylation with either a carbon nucleophile or a secondary alkyl chloride.

We report the design and synthesis of a class of hybrid latex particle that combines the elastomeric properties of polyolefins with the physicochemical diversity of acrylics. These hybrid polyolefin–acrylic particles are obtained in two steps, starting from the mechanical dispersion of a polyolefin resin to yield a colloidally stable particle dispersion, which is then used in a second step as a seed for the free radical emulsion polymerization of an acrylic phase. Imaging of the resulting particles by scanning electron and atomic force microscopy reveals a distinct lobed morphology, where acrylic polymer is associated with the surface of the polyolefin dispersion. Using gel permeation chromatography (GPC), we quantify the degree of grafting between the core and the acrylic phase, while analysis by dynamic mechanical analysis (DMA) shows that key properties of the polyolefin remain unaffected by the emulsion polymerization process. Process changes including varying the polyolefin/acrylic ratio, monomer addition method, initiator type, and acrylic composition can be used to control the surface coverage and size of the acrylic lobes, and therefore tune the particle morphology. This approach is modular both in terms of the polyolefin materials and additives that can be used to fabricate the core, as well as the physicochemical properties of the acrylic phase (composition, glass transition temperature, chemical functionality, etc.) and provides opportunities to design hybrid particles for a range of advanced applications.

The incorporation of hydrophobic and sparingly water-soluble monomers into emulsion polymer particles could lead to the development of new high-performance coatings, adhesives, personal care products, and other functional materials. Here, we show that the prototypical anionic surfactant sodium lauryl sulfate in combination with certain nonionic surfactants enables the incorporation of hydrophobic siloxane-containing monomers into conventional acrylic latex particles. This “mixed surfactant” method provides hydrophobic monomer loadings of up to 50 wt %, while undesirable macroscopic gel and the appearance of large particles due to microsuspension polymerization are held to <1 wt % (of total monomer). Fundamental experiments suggest that SLS and the secondary alcohol ethoxylate TERGITOL 15-S-9 surfactant increase monomer emulsion stability relative to other classes of nonionic surfactants examined. Increases in monomer emulsion droplet surface area and monomer solubilization/transport observed with this mixed surfactant system promote siloxane-containing monomer incorporation into growing latex particles. Our results and the guiding principles described here will jumpstart the development of polymerization processes for latex compositions that contain challenging or otherwise unusable sparingly soluble and water-insoluble monomers.

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This paper describes a new synthesis and separation method of nanoparticles (NPs) using a non-toxic, non-ionic surfactant systems. The purification steps did not use ethanol or acetone. Results indicate that the wild type bovine Carbonic Anhydrase (CA) activity was enhanced almost 4 times more than the CA encapsulated NPs fabricated by the traditional method. The NPs have are more hydrophilic and also have a higher zeta potential. The well dispersed CA PAA NPs with of 10-30 nm in diameter were obtained. This work also demonstrates a universal method for immobilizing fragile biomacromolecules in NP carriers for biomedical applications.

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