The simultaneous intracellular delivery of multiple types of payloads, such as hydrophobic drugs and nucleic acids, typically requires complex carrier systems. Herein, we demonstrate a self-deliverable form of nucleic acid-drug nanostructure that is composed almost entirely of payload molecules. Upon light activation, the nanostructure sheds the nucleic acid shell, while the core, which consists of prodrug molecules, disintegrates via an irreversible self-immolative process, releasing free drug molecules and small molecule fragments. We demonstrate that the nanostructures exhibit enhanced stability against DNase I compared with free DNA, and that the model drug (camptothecin) released exhibits similar efficacy as free, unmodified drugs toward cancer cells.
Herein, we report a class of molecular spherical nucleic acid (SNA) nanostructures. These nano-sized single molecules are synthesized from T polyoctahedral silsesquioxane and buckminsterfullerene C scaffolds, modified with 8 and 12 pendant DNA strands, respectively. These conjugates have different DNA surface densities and thus exhibit different levels of nuclease resistance, cellular uptake, and gene regulation capabilities; the properties displayed by the C SNA conjugate are closer to those of conventional and prototypical gold nanoparticle SNAs. Importantly, the C SNA can serve as a single entity (no transfection agent required) antisense agent to efficiently regulate gene expression. The realization of molecularly pure forms of SNAs will open the door for studying the interactions of such structures with ligands and living cells with a much greater degree of control than the conventional polydisperse forms of SNAs.
Optical phased arrays (OPAs) implemented in integrated photonic
circuits could enable a variety of 3D sensing, imaging, illumination,
and ranging applications, and their convergence in new lidar
technology. However, current integrated OPA approaches do not scale—in
control complexity, power consumption, or optical efficiency—to the
large aperture sizes needed to support medium- to long-range lidar. We
present the serpentine OPA (SOPA), a new OPA concept that addresses
these fundamental challenges and enables architectures that scale up
to large apertures. The SOPA is based on a serially interconnected
array of low-loss grating waveguides and supports fully passive, 2D
wavelength-controlled beam steering. A fundamentally space-efficient
design that folds the feed network into the aperture also enables
scalable tiling of SOPAs into large apertures with a high fill-factor.
We experimentally demonstrate, to the best of our knowledge, the first
SOPA using a 1450–1650 nm wavelength sweep to produce 16,500
addressable spots in a
27
×
610
array. We also demonstrate, for the
first time, far-field interference of beams from two separate OPAs on
a single silicon photonic chip, as an initial step towards long-range
computational imaging lidar based on novel active aperture
synthesis schemes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.