Many transfection techniques can deliver biomolecules into cells, but the dose cannot be controlled precisely. Delivering well-defined amounts of materials into cells is important for various biological studies and therapeutic applications. Here, we show that nanochannel electroporation can deliver precise amounts of a variety of transfection agents into living cells. The device consists of two microchannels connected by a nanochannel. The cell to be transfected is positioned in one microchannel using optical tweezers, and the transfection agent is located in the second microchannel. Delivering a voltage pulse between the microchannels produces an intense electric field over a very small area on the cell membrane, allowing a precise amount of transfection agent to be electrophoretically driven through the nanochannel, the cell membrane and into the cell cytoplasm, without affecting cell viability. Dose control is achieved by adjusting the duration and number of pulses. The nanochannel electroporation device is expected to have high-throughput delivery applications.

The synthesis of doxorubicin‐loaded metal–organic framework nanoparticles (NMOFs) coated with a stimuli‐responsive nucleic acid‐based polyacrylamide hydrogel is described. The formation of the hydrogel is stimulated by the crosslinking of two polyacrylamide chains, PA and PB, that are functionalized with two nucleic acid hairpins (4) and (5) using the strand‐induced hybridization chain reaction. The resulting duplex‐bridged polyacrylamide hydrogel includes the anti‐ATP (adenosine triphosphate) aptamer sequence in a caged configuration. The drug encapsulated in the NMOFs is locked by the hydrogel coating. In the presence of ATP that is overexpressed in cancer cells, the hydrogel coating is degraded via the formation of the ATP–aptamer complex, resulting in the release of doxorubicin drug. In addition to the introduction of a general means to synthesize drug‐loaded stimuli‐responsive nucleic acid‐based polyacrylamide hydrogel‐coated NMOFs hybrids, the functionalized NMOFs resolve significant limitations associated with the recently reported nucleic acid‐gated drug‐loaded NMOFs. The study reveals substantially higher loading of the drug in the hydrogel‐coated NMOFs as compared to the nucleic acid‐gated NMOFs and overcomes the nonspecific leakage of the drug observed with the nucleic‐acid‐protected NMOFs. The doxorubicin‐loaded, ATP‐responsive, hydrogel‐coated NMOFs reveal selective and effective cytotoxicity toward MDA‐MB‐231 breast cancer cells, as compared to normal MCF‐10A epithelial breast cells.

A novel concept to improve the catalytic functions of nucleic acids (DNAzymes) is introduced. The method involves the conjugation of a DNA recognition sequence (aptamer) to the catalytic DNAzyme, yielding a hybrid structure termed "nucleoapzyme". Concentrating the substrate within the "nucleoapzyme" leads to enhanced catalytic activity, displaying saturation kinetics. Different conjugation modes of the aptamer/DNAzyme units and the availability of different aptamer sequences for a substrate provide diverse means to design improved catalysts. This is exemplified with (i) The H2O2-mediated oxidation of dopamine to aminochrome using a series of hemin/G-quadruplex-dopamine aptamer nucleoapzymes. All nucleoapzymes reveal enhanced catalytic activities as compared to the separated DNAzyme/aptamer units, and the most active nucleoapzyme reveals a 20-fold enhanced activity. Molecular dynamics simulations provide rational assessment of the activity of the various nucleoapzymes. The hemin/G-quadruplex-aptamer nucleoapzyme also stimulates the chiroselective oxidation of L- vs D-DOPA by H2O2. (ii) The H2O2-mediated oxidation of N-hydroxy-L-arginine to L-citrulline by a series of hemin/G-quadruplex-arginine aptamer conjugated nucleoapzymes.

Although cellular therapies represent a promising strategy for a number of conditions, current approaches face major translational hurdles, including limited cell sources and the need for cumbersome pre-processing steps (for example, isolation, induced pluripotency)1–6. In vivo cell reprogramming has the potential to enable more-effective cell-based therapies by using readily available cell sources (for example, fibroblasts) and circumventing the need for ex vivo pre-processing7,8. Existing reprogramming methodologies, however, are fraught with caveats, including a heavy reliance on viral transfection9,10. Moreover, capsid size constraints and/or the stochastic nature of status quo approaches (viral and non-viral) pose additional limitations, thus highlighting the need for safer and more deterministic in vivo reprogramming methods11,12. Here, we report a novel yet simple-to-implement non-viral approach to topically reprogram tissues through a nanochannelled device validated with well-established and newly developed reprogramming models of induced neurons and endothelium, respectively. We demonstrate the simplicity and utility of this approach by rescuing necrotizing tissues and whole limbs using two murine models of injury-induced ischaemia.

A method to assemble light-responsive or pH-responsive microcapsules loaded with different loads (tetramethylrhodamine-modified dextran, TMR-D; microperoxidase-11, MP-11; CdSe/ZnS quantum dots; or doxorubicin-modified dextran, DOX-D) is described. The method is based on the layer-by-layer deposition of sequence-specific nucleic acids on poly(allylamine hydrochloride)-functionalized CaCO3 core microparticles, loaded with the different loads, that after the dissolution of the core particles with EDTA yields the stimuli-responsive microcapsules that include the respective loads. The light-responsive microcapsules are composed of photocleavable o-nitrobenzyl-phosphate-modified DNA shells, and the pH-responsive microcapsules are made of a cytosine-rich layer cross-linked by nucleic acid bridges. Irradiating the o-nitrobenzyl phosphate-functionalized microcapsules, λ = 365 nm, or subjecting the pH-responsive microcapsules to pH = 5.0, results in the cleavage of the microcapsule shells and the release of the loads. Preliminary studies address the cytotoxicity of the DOX-D-loaded microcapsules toward MDA-MB-231 breast cancer cells and normal MCF-10A breast epithelial cells. Selective cytotoxicity of the DOX-D-loaded microcapsules toward cancer cells is demonstrated.

Cu-functionalized carbon nitride nanoparticles (Cu-g-CN NPs), ∼200 nm, and Cu-carbon dots (Cu-C-dots), ∼8 nm, act as horseradish peroxidase-mimicking catalysts. The nanoparticles catalyze the generation of chemiluminescence in the presence of luminol/HO and catalyze the oxidation of dopamine by HO to form aminochrome. The Cu-g-CN-driven generation of chemiluminescence is used to develop a HO sensor and is implemented to develop a glucose detection platform and a sensor for probing glucose oxidase. Also, the Cu-C-dots are functionalized with the β-cyclodextrin (β-CD) receptor units. The concentration of dopamine, at the Cu-C-dots' surface, by means of the β-CD receptor sites, leads to a 4-fold enhancement in the oxidation of dopamine by HO to yield aminochrome compared to that of the unmodified C-dots.

Nanoparticles consisting of metal-organic frameworks (NMOFs) modified with nucleic acid binding strands are synthesized. The NMOFs are loaded with a fluorescent agent or with the anticancer drug doxorubicin, and the loaded NMOFs are capped by hybridization with a complementary nucleic acid that includes the ATP-aptamer or the ATP-AS1411 hybrid aptamer in caged configurations. The NMOFs are unlocked in the presence of ATP via the formation of ATP-aptamer complexes, resulting in the release of the loads. As ATP is overexpressed in cancer cells, and since the AS1411 aptamer recognizes the nucleolin receptor sites on the cancer cell membrane, the doxorubicin-loaded NMOFs provide functional carriers for targeting and treatment of cancer cells. Preliminary cell experiments reveal impressive selective permeation of the NMOFs into MDA-MB-231 breast cancer cells as compared to MCF-10A normal epithelial breast cells. High cytotoxic efficacy and targeted drug release are observed with the ATP-AS1411-functionalized doxorubicin-loaded NMOFs. The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201702102.conductivity material for fuel cells, [16][17][18] and as a composite material for sensing applications. [4,[19][20][21] Substantial recent efforts are directed toward the development of stimulitriggered reconfigurable nucleic acid structures (DNA switches and DNA machines). [22][23][24][25][26][27] Porous inorganic materials, e.g., SiO 2 nanoparticles, [28] microcapsules, [29] or organic hydrogels, [30][31][32] were loaded with substrates (or drugs) and caged with stimuli-responsive nucleic acid locks. In the presence of appropriate triggers, the stimuli-responsive loaded matrices were unlocked, resulting in the release of the loads. Different stimuli such as pH, [33] light, [34] heat, [35] catalytic nucleic acids, [36] or aptamer-ligand complexes [37] were used to unlock the substrate-loaded materials. Naturally, the capping of the highly porous substrate-loaded MOFs with stimuli-responsive DNAs could yield efficient DNA/ MOFs hybrids as drug delivery systems. Despite the chemical modification of MOFs with stimuli-responsive chemical capping units, [38][39][40][41][42][43] the integration of nucleic acids with MOFs is scarce and involved only the carrying of DNA. [44][45][46][47] Recently, we reported [48] on the successful entrapment of substrates in macrocrystalline MOFs protected by pH-responsive or K + -stabilized G-quadruplex capping units and the triggered unlocking of the MOFs, and the release of loads, by altering the pH, or their treatment with 18-crown-6 ether. While this study demonstrated the successful synthesis of stimuli-responsive DNAgated, substrate-loaded, microcrystalline MOFs, these materials suffer from a basic limitation because they are nonpermeable into cells. That is, their potential application as stimuli-responsive drug carriers is limited. The synthesis of nanometersized MOF particles is well established, [49][50][51][52][53][54] but ...

Cu-ion-modified graphene oxide nanoparticles, Cu-GO NPs, act as a heterogeneous catalyst mimicking functions of horseradish peroxidase, HRP, and of NADH peroxidase. The Cu-GO NPs catalyze the oxidation of dopamine to aminochrome by HO and catalyze the generation of chemiluminescence in the presence of luminol and HO. The Cu-GO NPs provide an active material for the chemiluminescence detection of HO and allow the probing of the activity of HO-generating oxidases and the detection of their substrates. This is exemplified with detecting glucose by the aerobic oxidation of glucose by glucose oxidase and the Cu-GO NP-stimulated chemiluminescence intensity generated by the HO product. Similarly, the Cu-GO NPs catalyze the HO oxidation of NADH to the biologically active NAD cofactor. This catalytic system allows its conjugation to biocatalytic transformations involving NAD-dependent enzyme, as exemplified for the alcohol dehydrogenase-catalyzed oxidation of benzyl alcohol to benzoic acid through the Cu-GO NPs-catalyzed regeneration of NAD.