Publikationen

Novel films consisting of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were fabricated by means of chemical vapor deposition technique and decorated with gold nanoparticles (AuNPs) possessing diameter of 14.0 nm. Electron optical microscopy analysis reveals that decoration of N-MWCNTs with AuNPs does not have any influence on their bamboo-shaped configuration. The electrochemical response of fabricated composite films, further denoted as N-MWCNTs/AuNPs, towards oxidation of dopamine (DA) to dopamine-o-quinone (DAQ) in the presence of ascorbic acid (AA) and uric acid (UA) was probed in real pig serum by means of cyclic voltammetry (CV) and square wave voltammetry (SWV). The findings demonstrate that N-MWCNTs/AuNPs exhibit slightly greater electrochemical response and sensitivity towards DA/DAQ compared to unmodified N-MWCNTs. It is, consequently, obvious that AuNPs improve significantly the electrochemical response and detection ability of N-MWCNTs. The electrochemical response of N-MWCNTs/AuNPs towards DA/DAQ seems to be significantly greater compared to that of conventional electrodes, such as platinum and glassy carbon. The findings reveal that N-MWCNTs/AuNPs could serve as powerful analytical sensor enabling analysis of DA in real serum samples.

The simple method of preparation of highly stable and purified C70 fullerene aqueous solution (C70FAS) is proposed. The features of structural stabilization of C70 fullerenes in an aqueous solution by studying their structural and optical properties using Raman, photoluminescence, infrared reflection-absorption, UV-VIS absorption, and dynamic light scattering spectroscopy methods were analyzed. The experimental results showed that the most likely mechanism for C70 fullerenes stabilization in water is surface hydroxylation with covalent attachment of water hydroxyls to C70 fullerene carbons. Raman and infrared absorption spectra of C70FAS showed characteristic vibrational bands of C70 fullerenes with a slight broadening and low-frequency shift of ∼1 cm^−1, indicating the attachment of water hydroxyls to the C70 fullerene carbons. The photoluminescence spectra showed excitonic emission bands of C70 molecules with intensity depending on their content. UV-VIS absorption spectra demonstrate the absorption bands typical for monomeric C70 fullerene. Finally, the dynamic light scattering data confirmed that C70FAS is a typical colloidal fluid containing both individual C70 molecules and their nano aggregates up to 100 nm. These findings provide insights into the stabilization mechanism of C70 fullerenes in water and may have implications for their potential application in nanobiotechnology.

The carbon fullerene C60 is an anti-inflammatory substance that reduces cellular stress levels. In this study, C60 fullerenes were deposited on complex dental implants to improve cell attachment and vitality. For the first time, fullerene C60 films were deposited via high-vacuum sublimation on complex-shaped Ti-6Al-4V dental implants with a threaded-screw design. The “as-deposited” fullerene C60 films were compared with fullerene C60 films on dental Ti-6Al-4V implants using a threaded-screw design after three weeks of incubation in Hank's balanced salt solution (HBSS). It was proven by Raman spectroscopy that the incubation in potassium and alkali-ion rich HBSS at 37 ˚C resulted in a reduction of monomeric fullerene C60 fraction and an increase in dimer, linear chain and polymerized C60 molecules. Furthermore, the structure of the C60 films differed depending on the measurement position on dental implants with a threaded-screw design. The fraction of monomeric fullerene C60 was highest on top of the trapezoidal thread, which had a micropatterned topography. Nano-indentations were performed at this position with a maximum load of 1000 μN. The fullerene C60 films showed a nano-hardness of 0.3 ± 0.1 GPa and a Young's modulus of 7.6 ± 3.6 GPa at this position, which is typical for monomeric fullerene C60 with weak interatomic interaction in the face-centred-cubic crystal structure. The murine embryonal calvarial stem-cell line MC3T3-E1 (ECACC, UK), which is driven toward osteogenic differentiation, spread out extremely well on the fullerene C60 film, with improved cell morphology compared to uncoated Ti-6Al-4V. Cell nuclei density were determined to be 237.5 cell nuclei per mm2 for the Ti-6Al-4V dental implants with a threaded-screw design with fullerene C60 coating in “as-deposited” condition. This was approximately 40 % better than that of uncoated Ti-6Al-4V dental implants with a threaded-screw design.

Photodynamic Therapy (PDT) is a non-invasive therapeutic modality that can treat a wide variety of cancer types by means of photosensitizer drug, light, and oxygen. Due to enhanced specificity and fewer side effects, PDT can be an alternative approach for cancer treatments. However, conventional photosensitizers (PSs) exhibit low selectivity, hydrophobicity, and limited photophysical properties. Nanotechnology emerges as a potential solution to these issues and improves PDT efficiency. Nanomaterials such as Carbon Quantum Dots (CQDs) and Graphene Quantum Dots (GrQDs) have been widely applied on PDT research recently, regarding their excellent photoluminescence properties, biocompatibility, as well as their hydrophilicity. The present review article summarizes the main features of PDT and carbon-based quantum dots with an emphasis on used PSs and methods for synthesis of carbon dots. Additionally, the most recent applications of CQDs and GrQDs in PDT have been extensively discussed. The main conclusion that arises is that carbon-based quantum dots seem to be a powerful tool in cancer diagnosis and treatment.

C60 fullerene (C60) as a nanocarbon particle, compatible with biological structures, capable of penetrating through cell membranes and effectively scavenging free radicals, is widely used in biomedicine. A protective effect of C60 on the biomechanics of fast (m. gastrocnemius) and slow (m. soleus) muscle contraction in rats and the pro- and antioxidant balance of muscle tissue during the development of muscle fatigue was studied compared to the same effect of the known antioxidant N-acetylcysteine (NAC). C60 and NAC were administered intraperitoneally at doses of 1 and 150 mg kg−1, respectively, daily for 5 days and 1 h before the start of the experiment. The following quantitative markers of muscle fatigue were used: the force of muscle contraction, the level of accumulation of secondary products of lipid peroxidation (TBARS) and the oxygen metabolite H2O2, the activity of first-line antioxidant defense enzymes (superoxide dismutase (SOD) and catalase (CAT)), and the condition of the glutathione system (reduced glutathione (GSH) content and the activity of the glutathione peroxidase (GPx) enzyme). The analysis of the muscle contraction force dynamics in rats against the background of induced muscle fatigue showed, that the effect of C60, 1 h after drug administration, was (15-17)% more effective on fast muscles than on slow muscles. A further slight increase in the effect of C60 was revealed after 2 h of drug injection, (7-9)% in the case of m. gastrocnemius and (5-6)% in the case of m. soleus. An increase in the effect of using C60 occurred within 4 days (the difference between 4 and 5 days did not exceed (3-5)%) and exceeded the effect of NAC by (32-34)%. The analysis of biochemical parameters in rat muscle tissues showed that long-term application of C60 contributed to their decrease by (10-30)% and (5-20)% in fast and slow muscles, respectively, on the 5th day of the experiment. At the same time, the protective effect of C60 was higher compared to NAC by (28-44)%. The obtained results indicate the prospect of using C60 as a potential protective nano agent to improve the efficiency of skeletal muscle function by modifying the reactive oxygen species-dependent mechanisms that play an important role in the processes of muscle fatigue development.