journal covers

2017: Journal of Materials Chemistry A / cover art


An article to Journal of Materials Chemistry A entitled Biologically-based pressure activated thin-film battery was selected for the cover art.

Abstract: There is an industrial interest in utilizing large volume manufacturing processes such as printing (e.g. stencil, roll-to-roll) to produce thin-film functional components. These components will require power sources, for example thin-film batteries, and it would be advantageous to be able to produce these powering items in-line with the components. Traditional primary thin-film batteries have limited storage capacities due to mass limitations and unavoidable losses. The current effort demonstrates a zinc/manganese oxide reserve battery that has been produced through combination of stencil and roll-to-roll printing on a polyethylene terephthalate (PET) substrate utilizing fish roe for the ion conducting electrolyte storage and separator. The creation of a reserve battery which can be activated when power is required by the deformation of the battery is an approach to extend battery storage times.

If you are interested in the full text of the article, it can be found here.

2016: Biomaterials Science / cover art


An article to Biomaterials Science entitled Sequestering survivin to functionalized nanoparticles: a strategy to enhance apoptosis in cancer cells was selected for the cover art.

Abstract: Surviving 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.

2015: Nanoscale / cover art


An article to Nanoscale entitled Nonvolatile optically-erased colloidal memristors was selected for the cover art.

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. The device exhibited a turn-on voltage of ca. −4.5 VDC and a 106 current ratio. A device in the ON high conductance state could be reverted to the OFF state with a short exposure to a 360 nm light source. The development of semiconducting colloidal inks that can be converted into electroactive devices through a continuous processing method is a critical step in the widespread adoption of these 2D manufacturing technologies for printed electronics.

2013: Advanced Functional Materials / cover art


An article to Advanced Functional Materials entitled Rapid and Continuous Hydrodynamically Controlled Fabrication of Biohybrid Microfibers was selected for the cover art.

Cell encapsulation is critical for many biotechnology applications including environmental remediation, bioreactors, and regenerative medicine. Here, the development of biohybrid microfi bers comprised of encapsulated bacteria in hydrogel matrices produced on-chip using microfl uidics is reported. The fiber production process utilizes hydrodynamic shaping of a cell-laden core fluid by a miscible sheath fluid. Production of the fibers containing viable bacteria was continuous in contrast to the more typical methods in which cells infiltrated or were attached to prepared fi bers. The biohybrid fibers were composed of poly (ethylene glycol dimethacrylate) matrices and individually both E. coli and B. cereus were explored as model cellular payloads. Post processing growth curves (24 h) of bacteria within fi bers were in excellent agreement with that of controls suggesting minimal impact. Finally, the biohybrid fibers showed even distribution of encapsulated cells and > 90% cell viability.

2013: Journal of Materials Chemistry / cover art


An article to the Journal of Materials Chemistry entitled Protein triggered fluorescence switching of near infrared emitting nanoparticles for contrast-enhanced imaging was selected for the cover art.

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. Dispersing the particles into an aqueous solution, such as phosphate buffered saline (PBS), resulted in an aggregation of the hydrophobic fluorophores and a cessation of emission. The emission can be reinstated, or activated, by the conversion of the surface-attached fluorophores from an aggregate to a monomeric species with the addition of an albumin. This activated probe can be deactivated and returned to a quenched state by a simple tryptic digestion of the albumin. The methodology for emission switching offers a path to maximize the signal from the typically weak quantum yield inherent in NIR fluorophores.

2012: Small /cover art


An article to Small entitled Substrate-Baited Nanoparticles: A Catch and Release Strategy for Enzyme Recognition and Harvesting was selected for the cover art.

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 purifi cation process. In this work, a model system is utilized to show the effi cacy 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. The enzymes are baited with azide modified carbazolyl moieties attached to poly(propargyl acrylate) nanoparticles through a click transformation. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicates the single-step procedure to immobilize the enzymes on the particles is capable of signifi cantly concentrating the protein from raw lysate and sequestering all required components of the protein to maintain bioactivity. These results establish a universal model applicable to concentrating and extracting known substrate–protein pairs, but it can be an invaluable tool in recognizing unknown protein–ligand affinities.

2011: Macromolecular Bioscience / cover art


An article to Macromolecular Bioscience entitled Selective Imaging and Killing of Cancer Cells with Protein-Activated Near-Infrared Fluorescing Nanoparticles was selected for the cover art.

We present a general approach for the selective imaging and killing of cancer cells using protein-activated near-infrared emitting and cytotoxic oxygen generating nanoparticles. Poly(propargyl acrylate) (PA) particles were surface modified through the copper-catalyzed azide/alkyne cycloaddition of azide-terminated indocyanine green (azICG), a near-infrared emitter, and poly(ethylene glycol) (azPEG) chains of various molecular weights. The placement of azICG onto the surface of the particles allowed for the chromophores to complex with bovine serum albumin when dispersed in PBS that resulted in an enhancement of the dye emission. In addition, the inclusion of azPEG with the chromophores onto the particle surface resulted in a synergistic ninefold enhancement of the fluorescence intensity, with azPEGs of increasing molecular weight amplifying the response. Human liver carcinoma cells (HepG2) overexpress albumin proteins and could be employed to activate the fluorescence of the nanoparticles. Preliminary PDT studies with HepG2 cells combined with the modified particles indicated that a minor exposure of 780nm radiation resulted in a statistically significant reduction in cell growth.

2010: Soft Matter / cover art


An article to Soft Matter entitled Designing fluoroprobes through Förster resonance energy transfer: surface modification of nanoparticles through “click” chemistry.

Abstract: Aqueous-phase 83 nm poly(propargyl acrylate) (PA) nanoparticles were surface-functionalized with sparingly water soluble fluorescent moieties through a copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) (i.e., “click” transformation) to produce fluoroprobes with a large Stokes shift. For moieties which could not achieve extensive surface coverage on the particles utilizing a standard click transformation procedure, the presence of β-cyclodextrin (β-CD) during the transformation enhanced the grafting density onto the particles. Moieties containing oxadiazolyl groups exhibited an 84% increase in grafting density when the transformation was performed in the presence of the oligosaccharide, going from 1.04 oxadiazolyl groups/nm2 to 1.91 oxadiazolyl groups/nm2. Similarly, an azide-modified coumarin 6 (AD1) underwent a 17% enhancement in grafting density from 1.56 AD1 groups/nm2 to 1.82 AD1 groups/nm2 when the transformation was done in the presence of β-CD. A polyethylene glycol modified naphthalimide-based emitter (AD2) was less sensitive to the presence of β-CD due to its elevated water solubility and exhibited a 5% increase in grafting density. In contrast, a carbazolyl-containing moiety which could achieve 100% surface coverage of the particles without the use of β-CD exhibited a slight retardation in the incorporation rate (and final grafting density) onto the particle when the oligosaccharide was employed. Photoluminescence studies of the particles modified singly or with multiple moieties indicated that when oxadiazolyl and carbazolyl groups were attached to the particles, an exciplex was formed that had a peak emission at ca. 400 nm. The absorption of the surface attached naphthalimide-based dye exhibited a complete spectral overlap with the carbazole/oxadiazole exciplex emission and photoluminescence excitation studies indicated an efficient energy transfer process from the carbazolyl and oxadiazolyl groups to the dye, resulting in an emission maxima at 510 nm for the modified particles and a total Stokes shift of 180 nm. This large Stokes shift is an important determinant of the ultimate sensitivity of a fluoroprobe, where scattering and background fluorescence can interfere with the detection of low concentrations of an analyte and the ability to manipulate the separation between the excitation and emission wavelengths is a critical parameter for optimal detection.

2008: Journal of Materials Chemistry / cover art


An article to the Journal of Materials Chemistry entitled Electroluminescent colloidal inks for flexographic roll-to-roll printing was selected for the cover art.

The academic and commercial interest in organic light-emitting devices is motivated in part by the potential of building devices utilizing simple and inexpensive fabrication routes, for example, commercial printing techniques. The focus on synthetically challenging small molecules and p-conjugated polymers for these devices is countered by the alternative of developing emissive materials that utilize an electroluminescent dye embedded in a hole and electron transporting host. In this effort, we exploit readily obtainable materials and simple fabrication routes to produce light emitting colloidal particles, which in turn allows us to invoke the concept of a ‘‘particle device’’. Specifically, we present colloidally based organic light emitting devices that can be designed to produce a range of colors by mixing together various ratios of red-, green-, and blue-emitting particles. These aqueous-based colloids are adaptable to form printing inks and may be utilized in fabricating devices through high-throughput commercial printing technologies.


2007: Advanced Materials / cover art


An article to Advanced Materials entitled Functionalization of Crystalline Colloidal Arrays through Click Chemistry was selected for the cover art.

The preparation of well-defined and regioselectively functionalized ordered colloidal particles through the exploitation of ‘click' transformations is presented; specifically, the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition between azides and terminal alkynes to form 1,2,3-triazoles is utilized. This approach is demonstrated through the attachment of 9-azidomethylanthracene to post-hydrogel stabilized, ordered poly(propargyl acrylate) colloidal particles.

2007: Journal of Materials Chemistry / cover art


An article to the Journal of Materials Chemistry entitled Polyaniline coated poly(butyl methacrylate) core–shell particles: roll-to-roll printing of templated electrically conductive structures was selected for the cover art.

Polyaniline coated poly(butyl methacrylate) core–shell particles were synthesized and formulated into electrically conductive colloidal inks appropriate for use in roll-to-roll printing. Since the first demonstration of an organic field-effect transistor, a specific interest in fabricating low-cost, large area organic electronics through the exploitation of conventional ink-jet, screen, or roll-to-roll printing technologies has developed. Using a commercial roll-to-roll printing press, interdigitated test figures were printed with the core–shell colloidal ink down to a line thickness of ca. 40 mm. The printed zones exhibited a conductivity of ca. 0.5 V21 cm21, though this conductivity could be modified by altering the composition of the ink to include more uncoated poly(butyl methacrylate) particles. Heating the printed zone above 35 uC allowed the core to flow, resulting in enhanced mechanical properties of the printed zone.

2005: Advanced Materials / cover art


An article to Advanced Materials entitled Multicolor Pattern Generation in Photonic Bandgap Composites was selected for the cover art.

The generation of complex, permanent, multicolor patterns in photonic bandgap films is demonstrated. The procedure allows for the overall spatial control of the reflected color on the surface of a photonic crystal, as well as the ability to define the visible or near-IR response of a patterned region through control of the stop-band wavelength. For example, the attached image presents a 10 mm wide, orange, “tiger paw” insignia templated on a green background.

2003: Advanced Materials / cover art


An article to Advanced Materials entitled Photonic Crystal Composites with Reversible High-Frequency Stop Band Shifts was selected for the cover art.

An approach to stabilize electrostatically stabilized colloidal arrays through an in-situ polymerization of a monomer around the ordered arrays has allowed the fabrication of photonic crystal composite with a range of thermomechanical properties and coupled optical properties. Composites with sub-ambient glass transitions exhibited reversible mechanochromic characteristics at room temperature. A poly(2-methoxyethyl acrylate)-based photonic crystal com¬posite was coupled directly to a piezoelectric actuator in order to study the static and dynamic stop-band tuning characteristics. The device exhibited a 172 nm total stop-band tuning range and could be modulated up to frequencies of 200 Hz.