Near infrared-absorbing gold nanoplasmonic particles (GNPs) are used as optical switches of gene interference and are remotely controlled using light. We have tuned optical switches to a wavelength where cellular photodamage is minimized. Optical switches are functionalized with double-stranded oligonucleotides. At desired times and at specific intracellular locations, remote optical excitation is used to liberate gene-interfering oligonucleotides. We demonstrate a novel gene-interfering technique offering spatial and temporal control, which is otherwise impossible using conventional gene-interfering techniques.Precise control of gene interference in living cells is in critical demand 1,2 for studying cellular signaling pathways, 3 quantitative cell biology, 4 systems biology, 5 and molecular cell biology. 6 In order to advance these dynamic cellular studies, nanoscale intracellular transmitter and receiver systems are required for the remote manipulation of biological systems. Remote electronic control of DNA hybridization by inductive coupling of radio frequency, 7 photouncaging of DNA by UV light, [8][9][10] and chromophore-based optical activation 11,12 of biomolecules have previously been demonstrated. Enzymes 13 and thermo-responsive polymers 14 have also been used to release biomolecules from carriers. Additionally, thermal ablation has previously been used to release large plasmids from carriers using high energy 15,16 or to destroy cells of interest. [17][18][19] However, gene interference with precise spatial and temporal resolution, minimal photodamage, as well as the selective coupling of the optical transmission frequency to different nanoscale transmitters has not yet been accomplished.Here, we present a new remote control switch of gene interference in living cells by using oligonucleotides on a nanoplasmonic carrier-based optical switch (ONCOS), short interfering oligonucleotides, and a near-infrared (NIR) laser transmitter. Gene interference by ONCOS occurs at the translational step. In the absence of gene interference, mRNA is transcribed from DNA in the nucleus and exported out to the cytoplasm (Figure 1b). The mRNA is then translated into the corresponding amino acids. This primary sequence of amino acids then folds into its final protein structure and is transported to the proper location in the cell. In the presence of ONCOS gene interference, optical switches are internalized within living cells ( Figure S1). The material, geometry, and size of these optical switches are specifically designed for use in ONCOS. GNPs are selected because of their stable and nontoxic properties in biological applications. 20,21 Rod-shaped GNPs have an aspect ratio (length/diameter) of 3.5, as shown in a scanning electron microscopy image in Figure 2b. Such geometry allows highly efficient photothermal conversion due to the matched resonant frequency, making it possible to activate gene release with minimized optical exposure time and low optical power. By carefully selecting the aspect ratio of these ...

Plasmon rulers, consisting of pairs of gold nanoparticles, allow single-molecule analysis without photobleaching or blinking; however, current plasmon rulers are irreversible, restricting detection to only single events. Here, we present a reversible plasmon ruler, comprised of coupled gold nanoparticles linked by a single aptamer, capable of binding individual secreted molecules with high specificity. We show that the binding of target secreted molecules to the reversible plasmon ruler is characterized by single-molecule sensitivity, high specificity, and reversibility. Such reversible plasmon rulers should enable dynamic and adaptive live-cell measurement of secreted single molecules in their local microenvironment.

Biologically functional cationic phospholipid-gold nanoplasmonic carriers have been designed to simultaneously exhibit carrier capabilities, demonstrate improved colloidal stability, and show no cytotoxicity under physiological conditions. Cargo, such as RNA, DNA, proteins, or drugs, can be adsorbed onto or incorporated into the cationic phospholipid bilayer membrane. These carriers are able to retain their unique nanoscale optical properties under physiological conditions, making them particularly useful in a wide range of imaging, therapeutic, and gene delivery applications that utilize selective nanoplasmonic properties.

The precise perturbation of gene circuits and the direct observation of signaling pathways in living cells are essential for both fundamental biology and translational medicine. Current optogenetic technology offers a new paradigm of optical control for cells; however, this technology relies on permanent genomic modifications with light-responsive genes, thus limiting dynamic reconfiguration of gene circuits. Here, we report precise control of perturbation and reconfiguration of gene circuits in living cells by optically addressable siRNA-Au nanoantennas. The siRNA-Au nanoantennas fulfill dual functions as selectively addressable optical receivers and biomolecular emitters of small interfering RNA (siRNA). Using siRNA-Au nanoantennas as optical inputs to existing circuit connections, photonic gene circuits are constructed in living cells. We show that photonic gene circuits are modular, enabling sub-circuits to be combined on-demand. Photonic gene circuits open new avenues for engineering functional gene circuits useful for fundamental bioscience, bioengineering, and medical applications.