DNA scaffold nanoparticles coated with HPMC/EC for oral delivery

2D DNA nanoporous scaffold promotes osteogenic differentiation of pre-osteoblasts

Biofunctional materials with nanomechanical parameters similar to bone tissue may promote the adherence, migration, proliferation, and differentiation of pre-osteoblasts. In this study, deoxyribonucleic acid (DNA) nanoporous scaffold (DNA-NPS) was synthesized by the polymerization of rectangular and double-crossover (DX) DNA tiles. The diagonally precise polymerization of nanometer-sized DNA tiles (A + B) through sticky end cohesion gave rise to a micrometer-sized porous giant-sheet material. The synthesized DNA-NPS exhibited a uniformly distributed porosity with a size of 25 ± 20 nm. The morphology, dimensions, sectional profiles, 2-dimensional (2D) layer height, texture, topology, pore size, and mechanical parameters of DNA-NPS have been characterized by atomic force microscopy (AFM). The size and zeta potential of DNA-NPS have been characterized by the zeta sizer. Cell biocompatibility, proliferation, and apoptosis have been evaluated by flow cytometry. The AFM results confirmed that the fabricated DNA-NPS was interconnected and uniformly porous, with a surface roughness of 0.125 ± 0.08035 nm. The elastic modulus of the DNA-NPS was 22.45 ± 8.65 GPa, which was comparable to that of native bone tissue. DNA-NPS facilitated pre-osteoblast adhesion, proliferation, and osteogenic differentiation. These findings indicated the potential of 2D DNA-NPS in promoting bone tissue regeneration.

The effective transfection of a low dose of negatively charged drug-loaded DNA-nanocarriers into cancer cells via scavenger receptors

DNA-nanotechnology-based nano-architecture scaffolds based on circular strands were designed in the form of DNA-nanowires (DNA-NWs) as a polymer of DNA-triangles. Circularizing a scaffold strand (84-NT) was the critical step followed by annealing with various staple strands to make stiff DNA-triangles. Atomic force microcopy (AFM), native polyacrylamide gel electrophoresis (PAGE), UV-analysis, MTT-assay, flow cytometry, and confocal imaging were performed to assess the formulated DNA-NWs and cisplatin (CPT) loading. The AFM and confocal microscopy images revealed a uniform shape and size distribution of the DNA-NWs, with lengths ranging from 2 to 4 μm and diameters ranging from 150 to 300 nm. One sharp band at the top of the lane (500 bp level) with the loss of electrophoretic mobility during the PAGE (native) gel analysis revealed the successful fabrication of DNA-NWs. The loading efficiency of CPT ranged from 66.85% to 97.35%. MTT and flow cytometry results showed biocompatibility of the blank DNA-NWs even at 95% concentration compared with the CPT-loaded DNA-NWs. The CPT-loaded DNA-NWs exhibited enhanced apoptosis (22%) compared to the apoptosis (7%) induced by the blank DNA-NWs. The release of CPT from the DNA-NWs was sustained at < 75% for 6 h in the presence of serum, demonstrating suitability for systemic applications. The IC50 of CPT@DNA-NWs was reduced to 12.8 nM CPT, as compared with the free CPT solution exhibiting an IC50 of 51.2 nM. Confocal imaging revealed the targetability, surface binding, and slow internalization of the DNA-NWs in the scavenger-receptor-rich cancer cell line (HepG2) compared with the control cell line.

Anti-glycemic potential of benzophenone thio/semicarbazone derivatives: synthesis, enzyme inhibition and ligand docking studies

Inhibition of dipeptidyl peptidase-IV (DPP-IV) has been identified as a promising approach for the treatment of type 2 diabetes mellitus (T2DM). Therefore, development of DPP-IV inhibitors with new chemical scaffold is of utmost importance to medicinal chemistry. In the present study, we identified benzophenone thio- and semicarbazone scaffolds as novel DPP-IV inhibitors. For that purpose, benzophenone thio- and semicarbazone were synthesized through a 2-step reaction. These newly synthetic derivatives were characterized by different spectroscopic techniques, including HREI-MS and NMR. whereas stereochemistry of the iminic bond was predicted by NOESY experiments. Thio- and semicarbazones derivatives were evaluated for their DPP-IV inhibitory potential and found to exhibit a good to moderate enzyme inhibitory activity. Most active and non-cytotoxic derivatives were further evaluated for their DPP-IV inhibitory potential in in cellulo model. The binding sites as well as affinity of active compounds for DPP- IV enzyme were predicted by in silico studies, and compared to a standard drug, sitagliptin. Pharmacophore studies of thio- and semicarbazones derivatives 1-29 suggest that substitution of aryl group, particularly a lipophilic substituents at C-4″ of benzene ring, and a hydroxyl at C-4' strongly influenced the DPP-IV inhibitory activity. Compound 9 showed the highest inhibitory activity (IC₅₀ = 15.0 ± 0.6 µM), whereas compounds 10, 17, 12, 14 and 23 showed a moderate activity with IC₅₀ values in the range of 28.9-39.2 µM. This study identifies thio- and semicarbazones as new classes of DPP-IV inhibitors which may translate into safe and effective therapeutics for a better management of type 2 diabetes.Communicated by Ramaswamy H. Sarma.

The integrin facilitated internalization of fibronectin-functionalized camptothecin-loaded DNA-nanofibers for high-efficiency anticancer effects

Camptothecin (CMPT) in a free form is extremely cytotoxic as well as hydrophobic drug, and is considered to be highly contagious for systemic administration. The fibronectin (FN)-functionalized DNA-based nanocarrier has been designed to load CMPT and target integrin (αvβ3) receptors which are highly expressed on the A549 cancer cells. Here, we report DNA nanocarrier in the form of DNA-nanofibers (DNA-NFs) capable of loading CMPT via strand intercalation in the GC (base pairs)-rich regions of the DNA duplex. Hence, our keen purpose was to explore the potential of DNA-NFs to load CMPT and assess the improvements of the outcomes in terms of enhanced therapeutic effects to integrin-rich A549 cancer cells with reduced cytotoxic effects to integrin-lacking HEK293 cells. DNA-NFs were formulated as a polymer of DNA triangles. DNA triangles arranged in a programmed way through the complementary overhangs present at the vertices. DNA triangles were primarily obtained through the annealing of the freshly circularized scaffold strands with the three distinct staple strands of specific sequences. The polymerized triangular tiles instead of forming two-dimensional nanosheets underwent self-coiling to give rise to DNA-NF-shaped structures. Flow cytometry and MTT assays were performed to observe cytotoxic and apoptotic effects on integrin-rich A549 cancer cells compared with the integrin-deficient HEK293 cells. AFM, native-page, and confocal experiments confirmed the polymerization of DNA triangles and the morphology of the resulting nanostructures. AFM and confocal images revealed the length of DNA-NFs to be 3-6 μm and the width from 70 to 110 nm. CMPT loading (via strands intercalation) in GC-rich regions of DNA-NFs and the FN functionalization (TAMRA tagged; red fluorescence) via amide chemistry using amino-modified strands of DNA-NFs were confirmed through the UV-shift analysis (> 10 nm shift) and confocal imaging. Blank DNA-NFs were found to be highly biocompatible in 2-640 μM concentrations. MTT assay and flow cytometry experiments revealed that CMPT-loaded DNA-NFs showed a dose-dependent decrease in the cell viability to integrin-rich A549 cancer cells compared with the integrin-deficient HEK293 cells. Conclusively, FN-functionalized, CMPT-loaded DNA-NFs effectively destroyed integrin-rich A549 cancer cells in a targeted manner compared with integrin-deficient HEK293 cells. Grapical abstract.

Synthesis of Ligand Functionalized ErbB-3 Targeted Novel DNA Nano-Threads Loaded with the Low Dose of Doxorubicin for Efficient In Vitro Evaluation of the Resistant Anti-Cancer Activity

PURPOSE

Doxorubicin (Dox) being a hydrophobic drug needs a unique carrier for the effective encapsulation with uniformity in the aqueous dispersion, cell culture media and the biological-fluids that may efficiently target its release at the tumor site.

METHODS

Circular DNA-nanotechnology was employed to synthesize DNA Nano-threads (DNA-NTs) by polymerization of triangular DNA-tiles. It involved circularizing a linear single-stranded scaffold strand to make sturdier and rigid triangles. DNA-NTs were characterized by the AFM and Native-PAGE tests. Dox binding and loading to the Neuregulin1 (NRG1) functionalized DNA based nano-threads (NF-DBNs) was estimated by the UV-shift analysis. The biocompatibility of the blank NRG-1/DNA-NTs and enhanced cytotoxicity of the NF-DBNs was assessed by the MTT assay. Cell proliferation/apoptosis was analyzed through the Flow-cytometry experiment. Cell-surface binding and the cell-internalization of the NF-DBNs was captured by the double-photon confocal microscopy (DPCM).

RESULTS

The AFM images revealed uniform DNA-NTs with the diameter 30 to 80 nm and length 400 to 800 nm. PAGE native gel was used for the further confirmation of the successful assembly of the strands to synthesize DNA-NTs that gave one sharp band with the decreased electrophoretic mobility down the gel. MTT assay showed that blank DNA-NTs were biocompatible to the cells with less cytotoxicity even at elevated concentrations with most of the cells (94%) remaining alive compared to the dose-dependent enhanced cytotoxicity of NF-DBNs further evidenced by the Flow-cytometry analysis.

CONCLUSION

Uniform and stiffer DNA-NTs for the potential applications in targeted drug delivery was achieved through circular DNA scaffolding.

Synthetic NRG-1 functionalized DNA nanospindels towards HER2/neu targets for in vitro anti-cancer activity assessment against breast cancer MCF-7 cells

DNA based nano-carriers synthesized from short circular scaffolds (circular DNA nanotechnology) attains stiffer topology for ligand functionalization (neuregulin-1/NRG-1 ligand) and biological applications (targeted drug delivery). Daunorubicin (DR) is a hydrophobic chemical that requires robust vectors to efficiently encapsulate and avoid its free dispersion in water, biological media and cell culture. Here we design DNA nanospindels (DNA-NS) to efficiently load DR and target the (highly expressed) HER2/neu receptors on the plasma membrane of drug-resistant MCF-7 (breast cancer) cells. DNA-NS were synthesized by polymerizing the DNA-triangles (utilizing 84-nt short circular scaffold strand) into larger DNA nano-ribbons characterized by the native-PAGE testing. AFM results revealed the spinning of DNA nanoribbons on its (own) axis because of the intrinsic curvature of the DNA double helix resulting in the formation of the firm and twisted DNA-NS with the diameter (50-70 nm) and length (0.5-4 μm). DA loading onto DNA-NS was confirmed by the UV shift analysis. The MTT results with the blank DNA-NS evidenced its biocompatibility (remained value of 93%) compared to the decreased viability of the MCF-7 cells after treatment with DNA-NS (DR loaded). These findings were further supported by the analysis of cell proliferation/apoptosis through flow cytometry showing 64% apoptosis after treating with the DR loaded DNA-NS. Hence, through the short circular DNA nanotechnology, we have achieved a stiffer, uniform, and biocompatible DNA-NS for applications in the targeted therapy.

Synthesis of vildagliptin conjugated metal nanoparticles for type II diabetes control: targeting the DPP-IV enzyme

Diabetes is one of the most prevalent diseases worldwide.