Gold colloids have fascinated scientists for over a century and are now heavily utilized in chemistry, biology, engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chemical functional groups, and, in certain cases, characterized with atomic-level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene-regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to molecule-based systems, but rather for their new physical and chemical properties, which confer substantive advantages in cellular and medical applications.

Organic electrode materials are very attractive for electrochemical energy storage devices because they can be flexible, lightweight, low cost, benign to the environment, and used in a variety of device architectures. They are not mere alternatives to more traditional energy storage materials, rather, they have the potential to lead to disruptive technologies. Although organic electrode materials for energy storage have progressed in recent years, there are still significant challenges to overcome before reaching large-scale commercialization. This review provides an overview of energy storage systems as a whole, the metrics that are used to quantify the performance of electrodes, recent strategies that have been investigated to overcome the challenges associated with organic electrode materials, and the use of computational chemistry to design and study new materials and their properties. Design strategies are examined to overcome issues with capacity/capacitance, device voltage, rate capability, and cycling stability in order to guide future work in the area. The use of low cost materials is highlighted as a direction towards commercial realization.

We demonstrate that novel oligonucleotide-modified gold nanoparticle probes hybridized to fluorophore-labeled complements can be used as both transfection agents and cellular "nanoflares" for detecting mRNA in living cells. Nano-flares take advantage of the highly efficient fluorescence quenching properties of gold, cellular uptake of oligonucleotide nanoparticle conjugates without the use of transfection agents, and the enzymatic stability of such conjugates, thus overcoming many of the challenges to creating sensitive and effective intracellular probes. Nano-flares exhibit high signaling, have low background fluorescence, and are sensitive to changes in the number of RNA transcripts present in cells.Probes to visualize and detect intracellular RNA including those used for in situ staining, 1 molecular beacons, 2 and fluorescent resonance energy transfer (FRET) pairs 3 are important tools to measure and quantify activity in living systems in response to external stimuli. 4 However, these probes are often difficult to transfect, require additional agents for cellular internalization, and can be unstable in cellular environments. These factors can lead to a high background signal and the inability to detect targets. Here we show how novel oligonucleotide-modified gold nanoparticle probes hybridized to fluorophore complements can be used as both transfection agents and cellular "nano-flares" for visualizing and quantifying RNA in living cells. Nano-flares take advantage of the highly efficient fluorescence quenching properties of gold, 5 cellular uptake of oligonucleotide nanoparticle conjugates without the use of transfection agents, and the enzymatic stability of such conjugates, 6 thus overcoming many of the challenges to creating sensitive and effective intracellular probes. Specifically, nano-flares exhibit high signaling, have low background fluorescence, and are sensitive to changes in the number of RNA transcripts present in cells. The discovery and subsequent development of the oligonucleotide-nanoparticle conjugate have led to a variety of new opportunities in molecular diagnostics 11 and materials design. 12 Recently, it has been demonstrated that oligonucleotide-functionalized nanoparticles enter cells and can act as antisense agents to control gene expression. 6 These "antisense particles" are not only delivery vehicles, 13 but also single entity regulation and transfection agents that undergo facile cellular internalization, resist enzymatic degradation, and bind intracellular targets with affinity constants that are as much as two orders of magnitude greater than free oligonucleotides. 14 Moreover, they can be easily modified with potent designer materials such as locked nucleic acids 15 and are nontoxic under conditions required for gene regulation.The nano-flares described herein are oligonucleotide functionalized nanoparticle conjugates designed to provide an intracellular fluorescence signal that correlates with the relative amount of a specific intracellular RNA. By utilizing nanopart...