Nanotechnology, Science and Applications最新文献

Background: Diamond nanoparticles (Nanodiamond) are biocompatible drug delivery platforms with outstanding surface properties. Their passage into the brain has been confirmed previously. Thus, nanodiamond could provide a drug delivery system to shuttle several drugs through the blood-brain barrier (BBB) which represents a real challenge for the effective delivery of several drugs into the brain. Amlodipine is a calcium channel blocker that cannot pass through BBB and may elicit neuroprotective effects to reverse calcium-induced excitotoxicity and mitochondrial dysfunction that underlie several neurologic disorders including Alzheimer's disease and stroke.

Aim: The study aimed to investigate the loading of amlodipine on nanodiamond particles.

Methods: Nanodiamond particles were oxidized in a strong oxidizing acidic mixture of sulfuric and nitric acids. Adsorption of amlodipine on nanodiamond particles was achieved in alkaline pH using various concentrations of sodium hydroxide. The loaded amlodipine was determined by high-performance liquid chromatography and confirmed by Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy.

Results: The highest percentage (41%) of loaded amlodipine onto nanodiamond particles was achieved in alkaline medium using 2 mM NaOH at a corresponding pH of 8.5. Also, characteristic FTIR bands of amlodipine and nanodiamond were shown obviously in the nanodiamond-amlodipine conjugates. Moreover, the successful loading of amlodipine on diamond nanoparticles was confirmed by transmission electron microscopy.

Conclusion: The present study demonstrates the successful loading of amlodipine onto nanodiamond particles. These findings offer a potential for applying diamond nanoparticles as a drug delivery system to shuttle amlodipine into the brain and open the door to deliver other similar drugs into the brain.

Among the various nano/biomaterials used in cancer treatment, the beauty and benefits of DNA nanocomposites are outstanding. The specificity and programmability of the base pairing of DNA strands, together with their ability to conjugate with different types of functionalities have realized unsurpassed potential for the production of two- and three-dimensional nano-sized structures in any shape, size, surface chemistry and functionality. This review aims to provide an insight into the diversity of static DNA nanodevices, including DNA origami, DNA polyhedra, DNA origami arrays and bioreactors, DNA nanoswitch, DNA nanoflower, hydrogel and dendrimer as young but promising platforms for cancer theranostics. The utility and potential of the individual formats in biomedical science and especially in cancer therapy will be discussed.

Purpose: Currently, there is a number of successfully implemented local hemostatic agents for external bleedings in forms of wound dressings and other topical materials. However, little has been done in the field of intravenous hemostatic agents. Here, we propose a new procedure to fabricate biocompatible protein nanocontainers (NCs) for intravenous injection allowing magneto-controllable delivery and short-term release of the hemostatic agent ε-aminocaproic acid (EACA).

Methods: The nanocontainers were synthesized by the desolvation method from bovine serum albumin (BSA) using methanol without any further crosslinking. Polyethylene glycol (PEG) was used both as a stabilization agent and for size control. Characterization of nanocontainers was performed by the transmission and scanning electron microscopy, dynamic light scattering, X-ray diffraction, and FTIR spectroscopy. Cytotoxicity was estimated using MTT assay. The dopant release from nanocontainers was measured spectrophotometrically using rhodamine B as a model molecule. The specific hemostatic activity was assessed by analyzing clot lysis and formation curve (CloFAL). Moreover, the ability for magneto targeting was estimated using the original flow setup made of a syringe pump and silicon contours.

Results: Fabricated nanocontainers had an average size of 186±24 nm and were constructed from building blocks-nanoparticles with average size ranged from 10 to 20 nm. PEG shell was also observed around nanocontainers with thickness 5-10 nm. NCs were proved to be completely non-cytotoxic even at concentrations up to 8 mg BSA/mL. Uptake capacity was near 36% while release within the first day was 17%. The analysis of the CloFAL curve showed the ability of NCs to inhibit the clot lysis successfully, and the ability of magneto targeting was confirmed under flow conditions.

Conclusion: The ability of synthesized NCs to deliver and release the therapeutic drug, as well as to accumulate at the desired site under the action of the magnetic field was proved experimentally.

Purpose: Evaluation of structural features, thermodynamics and kinetic properties of carbon nanofibers (CNFs) as artificial nanoscale enzymes (nanozyme).

Methods: Synthesis of CNFs was done using chemical vapor deposition, and transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to provide information on the morphology, elemental monitoring and impurity assay of the CNFs. The thermal features of the CNFs were evaluated using differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) derivative and TGA. The calculated thermo-physical parameters were melting temperature (Tm), weight loss maximum temperature (T_max ) and enthalpy of fusion (ΔH_fusion ). Catalytic activity was assayed by a 4-aminoantypyrine (4-AAP)-H₂O₂ coupled colorimetric system by UV-visible spectroscopy.

Results: FE-SEM and TEM analysis demonstrated parallel graphitic layers and uniformity of atomic orientation and morphology. The EDX spectra approved carbon element as major signal and presence of partial Ti as impurities of CNFs during CVD process. The DTA thermogram showed the endothermic process had a maximum temperature of 82.27°C at -15.48 mV and that thermal decomposition occurred at about 200°C. The TGA-differential gravimetric analysis thermogram showed that T_max was 700°C. The DSC heat flow curve showed a melting temperature (Tm) of 254.52°C, ΔH_fusion of 3.84 J^.g^-1, area under the curve of 58.58 mJ and T_e (onset) and T_f (end set) temperatures of 246.60°C and 285.67°C, respectively. The peroxidase activity of the CNFs obeyed the Michaelis-Menten equation with a double-reciprocal curve and the calculated K_m, K_cat and V_max kinetic parameters.

Conclusion: CNFs as peroxidase nanozymes are intrinsically strong and stable nanocatalysts under difficult thermal conditions. The peroxidase activity was demonstrated, making these CNFs candidates for analytical tools under extreme conditions.

[This retracts the article DOI: 10.2147/NSA.S24328.].