Synthesis of Semicrystalline Polyolefin Materials: Precision Methyl Branching via Stereoretentive Chain Walking.

We report the discovery of C-symmetric nickel catalysts capable of the regio- and isoselective polymerization of 1-butene to produce isotactic 4,2-poly(1-butene), a new semi-crystalline polyolefin. The catalyst exhibits enantioface selectivities as high as 84% and the resulting polymers display melting temperatures up to 86 °C. This system marks a rare example of preserving stereochemistry through a chain walking polymerization process.

Specific Binding of Liposomal Nanoparticles through Inverse Electron-Demand Diels-Alder Click Chemistry.

Here, we report a method to specifically bind liposomal radiopharmaceuticals to a CoCrMo alloy, which can be used in arterial stents, via an irreversible inverse electron-demand Diels-Alder reaction. Inspired by recent accomplishments in pre-targeted imaging using tetrazine--cyclooctene click chemistry, we synthesized Zr-labeled -cyclooctene-functionalized liposomal nanoparticles, which were validated on a tetrazine-appended polydopamine-coated CoCrMo surface. In efforts to ultimately translate this new material to biomedical applications, we compared the ability of Zr-TCO-liposomal nanoparticles (Zr-TCO-LNP) to be immobilized on the tetrazine surface to the control suspensions of non-TCO functionalized Zr-liposomal nanoparticles.

Imaging of Liver Tumors Using Surface-Enhanced Raman Scattering Nanoparticles.

Complete surgical resection is the ideal first-line treatment for most liver malignancies. This goal would be facilitated by an intraoperative imaging method that enables more precise visualization of tumor margins and detection of otherwise invisible microscopic lesions. To this end, we synthesized silica-encapsulated surface-enhanced Raman scattering (SERS) nanoparticles (NPs) that act as a molecular imaging agent for liver malignancies.

A "schizophotonic" all-in-one nanoparticle coating for multiplexed SE(R)RS biomedical imaging.

SERS nanoprobes for in vivo biomedical applications require high quantum yield, long circulation times, and maximum colloidal stability. Traditional synthetic routes require high metal-dye affinities and are challenged by unfavorable electrostatic interactions and limited scalability. We report the synthesis of a new near-IR active poly(N-(2-hydroxypropyl) methacrylamide) (pHPMA).

Guiding brain tumor resection using surface-enhanced Raman scattering nanoparticles and a hand-held Raman scanner.

The current difficulty in visualizing the true extent of malignant brain tumors during surgical resection represents one of the major reasons for the poor prognosis of brain tumor patients. Here, we evaluated the ability of a hand-held Raman scanner, guided by surface-enhanced Raman scattering (SERS) nanoparticles, to identify the microscopic tumor extent in a genetically engineered RCAS/tv-a glioblastoma mouse model. In a simulated intraoperative scenario, we tested both a static Raman imaging device and a mobile, hand-held Raman scanner.