Probing Light-Matter Interactions: Fluorescence Lifetime Manipulation in a Crystalline Colloidal Array.

The connection between a structured environment and the decay kinetics of an embedded emitter is explored by copolymerizing a naphthalimide derivative within polystyrene-based nanoparticles. The nanoparticles spontaneously self-assemble into a crystalline colloidal array, resulting in a partial photonic bandgap, or rejection wavelength, in the visible regime. The rejection wavelength of the liquid ordered array can be shifted across the emission spectrum of the nanoparticles by dilution with deionized water, which increases the interparticle spacing of the array.

Synthesis, electropolymerization and functionalization click chemistry of -alkynylated dithieno[3,2-:2',3'-]pyrrole.

A new N-alkynylated dithieno[3,2-:2',3'-]pyrrole (DTP) monomer was synthesized using a Buchwald-Hartwig amination of 3,3'-dibromo-2,2'-bithiophene with pent-4-yn-1-amine. The obtained monomer was investigated for the possibility of a pre-polymerization modification Huisgen 1,3-dipolar cycloaddition ("click") reaction with azide-containing organic compounds. The synthesized N-alkynylated DTP monomer is soluble in a number of organic solvents and reacts with organic azides "click" reactions in mild conditions, achieving high yields.

Radioluminescent Photonic Bandgap Hydrogels: Mechanochromic Tunable Emissions.

Fully organic, radioluminescent crystalline colloidal arrays (CCAs) with covalently incorporated emitters were synthesized by using up to three organic fluorophores that were Förster resonance energy transfer (FRET) pairs with each other. The emitters were covalently incorporated into monodisperse poly(styrene--propargyl acrylate) nanoparticles in various combinations, resulting in blue-, green-, and red-emitting CCAs when excited with an X-ray source. The negatively charged surfaces of the monodisperse nanoparticles caused self-assembly into a crystal-like structure, which resulted in a partial photonic bandgap (i.

Enhanced radioluminescence of yttrium pyrosilicate nanoparticles rare earth multiplex doping.

A series of multi-doped yttrium pyrosilicate (YPS) nanoparticles were synthesized using a high temperature multi-composite reactor, and used to explore the radioluminescent properties that have potential for biological applications. The luminescent activators explored in this work were cerium, terbium, and europium. A series of mono-doped YPS nanoparticles were synthesized that have optical and X-ray luminescent properties that span the entire visible spectrum.

Development of dispersible radioluminescent silicate nanoparticles through a sacrificial layer approach.

X-rays offer low tissue attenuation with high penetration depth when used in medical applications and when coupled with radioluminescent nanoparticles, offer novel theranostic opportunities. In this role, the ideal scintillator requires a high degree of crystallinity for an application relevant radioluminescence, yet a key challenge is the irreversible aggregation of the particles at most crystallization temperatures. In this communication, a high temperature multi-composite reactor (HTMcR) process was successfully developed to recrystallize monodisperse scintillating particulates by employing a core-multishell architecture.

Click-Engineered, Bioresponsive, and Versatile Particle-Protein-Dye System.

We present a multifunctional polymer based nanoparticle platform for personalized nanotheranostic applications, which include photodynamic therapy and active targeting. In this system, poly(propargyl acrylate) (PA) particles were surface-modified with organic ligands and fluorophores (the payload) through an environmentally-sensitive linker. An azide modified bovine serum albumin (azBSA) was employed as the linker.

Organic Fluorophore Coated Polycrystalline Ceramic LSO:Ce Scintillators for X-ray Bioimaging.

The current effort demonstrates that lutetium oxyorthosilicate doped with 1-10% cerium (LuSiO:Ce, LSO:Ce) radioluminescent particles can be coated with a single dye or multiple dyes and generate an effective energy transfer between the core and dye(s) when excited via X-rays. LSO:Ce particles were surface modified with an alkyne modified naphthalimide (6-piperidin-1-yl-2-prop-2-yn-1-yl-1 H-benzo[ de]isoquinoline-1,3-(2 H)-dione, AlNap) and alkyne modified rhodamine B ( N-(6-diethylamino)-9-{2-[(prop-2-yn-1-yloxy)carbonyl]phenyl}-3 H-xanthen-3-ylidene)- N-ethylethanaminium, AlRhod) derivatives to tune the X-ray excited optical luminescence from blue to green to red using Förster Resonance Energy Transfer (FRET). As X-rays penetrate tissue much more effectively than UV/visible light, the fluorophore modified phosphors may have applications as bioimaging agents.

Temperature responsive nanoparticles: poloxamers as a modulator of Förster resonance energy transfer (FRET).

An effective strategy to control the Förster resonance energy transfer (FRET) of a donor/acceptor emitter pair that were attached to a 60 nm poly(propargyl acrylate)(PA) nanoparticle using temperature variations was developed. The size dependent properties of a poly-(ethylene oxide)-poly-(propylene oxide)-poly-(ethylene oxide) (PEO-PPO-PEO) block copolymer (poloxamer) was exploited to vary the spatial separation of the emitters and vary the FRET efficiency. Specifically, a 2% change in FRET efficiency between the donor/acceptor pair was achieved per 1 °C change in temperature from 49 °C to 60 °C when using a poloxamer of 2950 g mol-1 molecular weight, with sections of PPO consisting of 32 repeat units, PEO sections consisting of 12 repeat units and a lower critical solution temperature (LCST) of 58 °C.

Bovine serum albumin coated nanoparticles for in vitro activated fluorescence.

A fluorophore modified nanoparticle was developed that can only fluoresce when a specific environmental parameter interacts with the system. The model system consisted of an azide modified bovine serum albumin (azBSA) that had been covalently attached to an alkyne modified silicon phthalocyanine (alSiPc) derivative through a copper catalyzed azide/alkyne Huisgen cycloaddition (click reaction). The azBSA/alSiPc assembly was then clicked to a ca.

Sequestering survivin to functionalized nanoparticles: a strategy to enhance apoptosis in cancer cells.

Survivin belongs to the family of inhibitor of apoptosis proteins (IAP) and is present in most cancers while being below detection limits in most terminally differentiated adult tissues, making it an attractive protein to target for diagnostic and, potentially, therapeutic roles. Sub-100 nm poly(propargyl acrylate) (PA) particles were surface modified through the copper-catalyzed azide/alkyne cycloaddition of an azide-terminated survivin ligand derivative (azTM) originally proposed by Abbott Laboratories and speculated to bind directly to survivin (protein) at its dimer interface. Using affinity pull-down studies, it was determined that the PA/azTM nanoparticles selectively bind survivin and the particles can enhance apoptotic cell death in glioblastoma cell lines and other survivin over-expressing cell lines such as A549 and MCF7 relative to cells incubated with the original Abbott-derived small molecule inhibitor.

Nonvolatile optically-erased colloidal memristors.

A nonconjugated methacrylate terpolymer containing carbazole moieties (electron donors), 1,3,4-oxadiazole moieties (electron acceptors), and Coumarin-6 in the pendant groups was synthesized via free radical copolymerization of methacrylate monomers containing the respective functional groups. The terpolymer was formed into 57 nm particles through a mini-emulsion route. For a thin 100 nm film of the fused particles sandwiched between an indium-tin oxide (ITO) electrode and an Al electrode, the structure behaved as a nonvolatile flash (rewritable) memory with accessible electronic states that could be written, read, and optically erased.

Protein triggered fluorescence switching of near-infrared emitting nanoparticles for contrast-enhanced imaging.

Sub-100 nm colloidal particles which are surface-functionalized with multiple environmentally-sensitive moieties have the potential to combine imaging, early detection, and the treatment of cancer with a single type of long-circulating "nanodevice". Deep tissue imaging is achievable through the development of particles which are surface-modified with fluorophores that operate in the near-infrared (NIR) spectrum and where the fluorophore's signal can be maximized by "turning-on" the fluorescence only in the targeted tissue. We present a general approach for the synthesis of NIR emitting nanoparticles that exhibit a protein triggered activation/deactivation of the emission.

Magnetic nanoclusters exhibiting protein-activated near-infrared fluorescence.

Composite nanoclusters with chemical, magnetic, and biofunctionality offer broad opportunities for targeted cellular imaging. A key challenge is to load a high degree of targeting, imaging, and therapeutic functionality onto stable metal-oxide nanoparticles. Here we report a route for producing magnetic nanoclusters (MNCs) with alkyne surface functionality that can be utilized as multimodal imaging probes.

Substrate-baited nanoparticles: a catch and release strategy for enzyme recognition and harvesting.

The isolation of a single type of protein from a complex mixture is vital for the characterization of the function, structure, and interactions of the protein of interest and is typically the most laborious aspect of the protein purification process. In this work, a model system is utilized to show the efficacy of synthesizing a "baited" nanoparticle to capture and recycle enzymes (proteins that catalyze chemical reactions) from crude cell lysate. Enzyme trapping and recycling is illustrated with the carbazole 1,9a-dioxygenase (CARDO) system, an enzyme important in bioremediation and natural product synthesis.

Manipulation of Förster energy transfer of coupled fluorophores through biotransformation by Pseudomonas resinovorans CA10.

An alkyne-terminated anthracene and azide-terminated carbazole were joined through a copper-catalyzed cycloaddition to form a joined donor/acceptor pair. The photonic pair exhibited energy transfer when excited at the peak absorbance of carbazole and fluoresced with an anthracene spectral response. The fluorescent behavior was confirmed as Förster energy transfer (FRET).