DNAzyme-Functionalized Nanomaterials: Recent Preparation, Current Applications, and Future Challenges.

DNAzyme-nanomaterial bioconjugates are a popular hybrid and have received major attention for diverse biomedical applications, such as bioimaging, biosensor development, cancer therapy, and drug delivery. Therefore, significant efforts are made to develop different strategies for the preparation of inorganic and organic nanoparticles (NPs) with specific morphologies and properties. DNAzymes functionalized with metal-organic frameworks (MOFs), gold nanoparticles (AuNPs), graphene oxide (GO), and molybdenum disulfide (MoS2 ) are introduced and summarized in detail in this review. Moreover, the focus is on representative examples of applications of DNAzyme-nanomaterials over recent years, especially in bioimaging, biosensing, phototherapy, and stimulation response delivery in living systems, with their several advantages and drawbacks. Finally, the perspective regarding the future directions of research addressing these challenges is also discussed and highlighted.

"On Water" Direct C-3 Arylation of 2H-Pyrazolo[3,4-b]pyridines.

An "on water" palladium-catalyzed direct (hetero)arylation of 2H-pyrazolo[3,4-b]pyridines has been developed. The reactions proceeds smoothly with at low catalytic loading at low temperature providing the C3 (hetero)arylated products in good to excellent isolated yields. Free NH 3-arylated 7-azaindazoles were also prepared by simple cleavage of the N-protected groups.

A fluorescence biosensor based on DNA aptamers-COF for highly selective detection of ATP and thrombin.

Due to their distinctive physical, chemical, electrical, and optical properties as well as their prospective uses, 2D covalent organic framework (COF) have attracted much attention. Herein, TaTPA-COF was effectively synthesized from the condensation of TTA and TFPA using a facile solvothermal method and characterized by SEM image, FT-IR spectra, and PXRD pattern. The generated bulk TaTPA-COF materials combined with DNA aptamers are utilized as the acceptor (quencher) for the highly sensitive and selective detection of adenosine 5'-triphosphate (ATP) and thrombin, with a novel fluorescence biosensing platform and a proof-of-concept application.

Pyrido[2',1':2,3]imidazo[4,5-c]isoquinolin-5-amines as Potential Cytotoxic Agents against Human Neuroblastoma.

We report herein the evaluation of various pyrido[2',1':2,3]imidazo[4,5-c]isoquinolin-5-amines as potential cytotoxic agents. These molecules were obtained by developing the multicomponent Groebke-Blackburn-Bienaymé reaction to yield various pyrido[2',1':2,3]imidazo[4,5-c]quinolines which are isosteres of ellipticine whose biological activities are well established. To evaluate the anticancer potential of these pyrido[2',1':2,3]imidazo[4,5-c]isoquinolin-5-amine derivatives in the human neuroblastoma cell line, the cytotoxicity was examined using the WST-1 assay after 72 h drug exposure. A clonogenic assay was used to assess the ability of treated cells to proliferate and form colonies. Protein expressions (Bax, bcl-2, cleaved caspase-3, cleaved PARP-1) were analyzed using Western blotting. The colony number decrease in cells was 50.54%, 37.88% and 27.12% following exposure to compounds 2d, 2g and 4b respectively at 10 µM. We also show that treating the neuroblastoma cell line with these compounds resulted in a significant alteration in caspase-3 and PARP-1 cleavage.

Crystal structure and Hirshfeld surface analysis of N-(tert-but-yl)-2-(phenyl-ethyn-yl)imidazo[1,2-a]pyridin-3-amine.

The bicyclic imidazo[1,2-a]pyridine core of the title compound, C19H19N3, is relatively planar with an r.m.s. deviation of 0.040 Å. The phenyl ring is inclined to the mean plane of the imidazo[1,2-a]pyridine unit by 18.2 (1)°. In the crystal, mol-ecules are linked by N-H⋯H hydrogen bonds, forming chains along the c-axis direction. The chains are linked by C-H⋯π inter-actions, forming slabs parallel to the ac plane. The Hirshfeld surface analysis and fingerprint plots reveal that the crystal structure is dominated by H⋯H (54%) and C⋯H/H⋯C (35.6%) contacts. The crystal studied was refined as an inversion twin.

Efficient synthesis and first regioselective C-6 direct arylation of imidazo[2,1-c][1,2,4]triazine scaffold and their evaluation in H2O2-induced oxidative stress.

Oxidative stress and apoptosis are both associated with various acute and chronic disorders. Thus, the aim of the present study is to synthesize imidazo[2,1-c][1,2,4]triazines derivatives and to evaluate their effects in H2O2-induced oxidative stress in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in stress and apoptosis-related proteins were investigated by PathScan® Stress and Apoptosis Signaling Antibody Array kit and Western Blot technique. In particular, four compounds were found to protect SH-SY5Y cells from H2O2-induced toxicity by increasing Bcl-2/Bax ratio, regulating PI3-K/Akt cascade and inhibiting the ERK pathway.

Domino Aza-Michael-ih-Diels-Alder Reaction to Various 3-Vinyl-1,2,4-triazines: Access to Polysubstituted Tetrahydro-1,6-naphthyridines.

A straightforward domino aza-Michael-inverse-electron-demand-hetero-Diels-Alder/retro-Diels-Alder reaction between primary and secondary propargylamine derivatives and 3-vinyl-1,2,4-triazines is developed highlighting not only the uniqueness of this dual-heterocyclic platform but also a novel and unprecedented path to polysubstituted tetrahydro-1,6-naphthyridine scaffolds.

Synthesis of new heterocyclic compounds based on pyrazolopyridine scaffold and evaluation of their neuroprotective potential in MPP+-induced neurodegeneration.

Neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and Huntington's disease affect millions of people in the world. Thus several new approaches to treat brain disorders are under development. The aim of the present study is to synthesize potential neuroprotective heterocyclic compounds based on pyrazolopyridine derivatives and then to evaluate their effects in MPP+-induced neurodegeneration in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in apoptosis-related proteins including bax, Bcl-2, Bcl-xl and caspase-3 were investigated by western blot technique. Based on the cell viability results obtained by MTT assay, the percentage of neuroprotection-induced by compounds against MPP+-induced neurotoxicity in SH-SY5Y cells was between 20% and 30% at 5 µM concentrations of all synthesized compounds. Moreover, the downregulation in pro-apoptotic proteins including bax and caspase-3 were found following the novel synthesized compounds treatments and these effects were observed in a dose-dependent manner. Our results provide an evidence that these heterocyclic compounds based on pyrazolopyridine derivatives may have a role on dopaminergic neuroprotection via antiapoptotic pathways.