Antonin Broz

Influence of the fetal bovine serum proteins on the growth of human osteoblast cells on graphene

The influence of single-layer graphene produced by chemical vapor deposition on human osteoblast cells under different conditions was studied. Measurements probed the ability of cells to adhere and proliferate on graphene compared with SiO(2)/Si substrates and standard tissue culture plastic when cells were incubated for the first 2 h in the presence or the absence of fetal bovine serum (FBS), thus influencing the initial, direct interaction of cells with the substrate. It was found that after 48 h of human osteoblast incubation on graphene films, there were a comparable number of cells of a similar size irrespective of the presence or the absence of serum proteins. On the other hand, a strong initial influence through the presence of FBS proteins on cell number and cell size was observed in the case of the SiO(2)/Si substrate and control plastic. Thus, our study showed that the initial presence/absence of FBS in the medium does not determine cell fate in the case of a graphene substrate, which is very unusual and different from the behavior of cells on other materials.

The impact of doped silicon quantum dots on human osteoblasts

Silicon (Si) nanostructures allow for the expansion of the application spectrum of this important semiconductor material with respect to the fields of optoelectronics and photonics. At the same time, the significant potential of Si quantum dots (SiQDs) has been revealed in terms of their potential application in the areas of biology and medicine due to their biocompatibility, low toxicity and natural biodegradability, unlike currently used semiconductor quantum dots. As far as this study is concerned, SiQDs co-doped with boron and phosphorus were used for the in vitro evaluation of their cytotoxicity in human osteoblasts. Two chemically identical types of SiQD differing in terms of their size and photoluminescence (PL) were studied. They both display long-lasting dispersion in methanol and even in aqueous media as well as PL which is not sensitive either to changes in the environment or surface modifications. Our experiments revealed significant differences between the two types of SiQD tested in regard to their behavior in a cell culture environment depending on increasing concentration (25–125 μg ml−1) and cultivation conditions (the presence or absence of proteins from the fetal bovine serum – a component of the cultivation medium). A detailed description of their optical parameters and the evaluation of zeta potential enhance the understanding of the complexities of the in vitro results obtained.

Silicon nanocrystals and nanodiamonds in live cells: photoluminescence characteristics, cytotoxicity and interaction with cell cytoskeleton

The number of newly developed nanomaterials is steadily increasing but only a few are suitable for applications in biology. These nanomaterials are often made from harmful compounds and there is no convenient technique to remove them from the body after application. This study is focused on silicon nanocrystals and nanodiamonds, which are two promising nanomaterials for bio-applications. Silicon nanocrystals (Si-NCs) are exceptional since they provide several desired properties: low cytotoxicity, suitability for chemical activation, efficient photoluminescence, and bio-degradability. All these parameters promote application of Si-NCs in living organisms and even human medicine. Nanodiamonds (NDs), on the other hand, are non-biodegradable which limits their use to mostly long term in vitro studies. However, when using these nanomaterials one needs to address the effect of accumulation and aggregation of such materials in cells and how it contributes to the overall cytotoxicity. Here, we present studies on the interaction of two promising nanomaterials Si-NCs and NDs with actin structure of mammalian cells, evaluation of their cytotoxicity by various methods, and observation of single nanoparticle luminescence spectra within living cells. According to our results Si-NCs are more promising for application in nanomedicine compared to NDs.

The Application of Nanodiamond in Biotechnology and Tissue Engineering

Diamond in the allotrope form consists of carbon atoms arranged in a cubic crystal structure covalently bonded in sp3 hybridization. Diamond has emerged as a very promising material for various biomedical applications due to its excellent mechani‐ cal properties (hardness, low friction coefficient, good adhesiveness to the underlying substrate, good interlayer cohesion), optical properties (the ability to emit intrinsic luminescence), electrical properties (good insulator in the pristine state and semicon‐ ductor after doping), chemical resistance (low chemical reactivity and resistance to wet etching) and biocompatibility (little if any toxicity and immunogenicity). For ad‐ vanced biomedical applications, diamond is promising particularly in its nanostruc‐ tured forms, namely nanoparticles, nanostructured diamond films and composite scaffolds in which diamond nanoparticles are dispersed in a matrix (mainly nanodia‐ mond-loaded nanofibrous scaffolds). This chapter summarizes both our long-term experience and that of other research groups in studies focusing on the interaction of cells (particularly bone-derived cells) with nanodiamonds as nanoparticles, thin films and composites with synthetic polymers. Their potential applications in bioimaging, biosensing, drug delivery, biomaterial coating and tissue engineering are also reviewed.

Stochastic model explains formation of cell arrays on H/O-diamond patterns

Cell migration plays an important role in many biological systems. A relatively simple stochastic model is developed and used to describe cell behavior on chemically patterned substrates. The model is based on three parameters: the speed of cell movement (own and external), the probability of cell adhesion, and the probability of cell division on the substrate. The model is calibrated and validated by experimental data obtained on hydrogen- and oxygen-terminated patterns on diamond. Thereby, the simulations reveal that: (1) the difference in the cell movement speed on these surfaces (about 1.5×) is the key factor behind the formation of cell arrays on the patterns, (2) this difference is provided by the presence of fetal bovine serum (validated by experiments), and (3) the directional cell flow promotes the array formation. The model also predicts that the array formation requires mean distance of cell travel at least 10% of intended stripe width. The model is generally applicable for biosensors using diverse cells, materials, and structures.