Design, fabrication, and characterization of a multimodal reconfigurable bioreactor for bone tissue engineering.

In the past decades, bone tissue engineering developed and exploited many typologies of bioreactors, which, besides providing proper culture conditions, aimed at integrating those bio-physical stimulations that cells experience in vivo, to promote osteogenic differentiation. Nevertheless, the highly challenging combination and deployment of many stimulation systems into a single bioreactor led to the generation of several unimodal bioreactors, investigating one or at mostly two of the required biophysical stimuli. These systems miss the physiological mimicry of bone cells environment, and often produced contrasting results, thus making the knowledge of bone mechanotransduction fragmented and often inconsistent. To overcome this issue, in this study we developed a perfusion and electroactive-vibrational reconfigurable stimulation bioreactor to investigate the differentiation of SaOS-2 bone-derived cells, hosting a piezoelectric nanocomposite membrane as cell culture substrate. This multimodal perfusion bioreactor is designed based on a numerical (finite element) model aimed at assessing the possibility to induce membrane nano-scaled vibrations (with ~12 nm amplitude at a frequency of 939 kHz) during perfusion (featuring 1.46 dyn cm-2 wall shear stress), large enough for inducing a physiologically-relevant electric output (in the order of 10 mV on average) on the membrane surface. This study explored the effects of different stimuli individually, enabling to switch on one stimulation at a time, and then to combine them to induce a faster bone matrix deposition rate. Biological results demonstrate that the multimodal configuration is the most effective in inducing SaOS-2 cell differentiation, leading to 20-fold higher collagen deposition compared to static cultures, and to 1.6- and 1.2-fold higher deposition than the perfused- or vibrated-only cultures. These promising results can provide tissue engineering scientists with a comprehensive and biomimetic stimulation platform for a better understanding of mechanotransduction phenomena beyond cells differentiation.

Effects of cerium oxide nanoparticles on PC12 neuronal-like cells: proliferation, differentiation, and dopamine secretion.

PURPOSE: Oxidative stress has been found to play a key role in several diseases, that range from cancer to neurodegenerative disorders. Besides traditional anti-oxidant agents, in recent years much attention has been focused on nanotechnological solutions, including cerium oxide nanoparticles (nanoceria). METHODS: Thanks to its extraordinary catalytic properties, nanoceria mimics the activity of superoxide dismutase and of catalase, therefore acting as a reactive oxygen species (ROS) scavenger in many biological contexts. In this paper, we report on nanoceria interactions with PC12 cell line, that represents a valuable model for many features of central dopaminergic neurons. RESULTS: Nanoceria confirmed a strong anti-ROS action but, most interestingly, also showed beneficial effects on both cell differentiation and dopamine production. CONCLUSIONS: Even if deeper examinations will be necessary in order to better clarify the mechanisms at the base of the documented effects, nanoceria demonstrated a significant potential as pharmacological agent in the treatment of neurological disorders.

Zwitterionic Nanofibers of Super-Glue for Transparent and Biocompatible Multi-Purpose Coatings.

Here we show that macrozwitterions of poly(ethyl 2-cyanoacrylate), commonly called Super Glue, can easily assemble into long and well defined fibers by electrospinning. The resulting fibrous networks are thermally treated on glass in order to create transparent coatings whose superficial morphology recalls the organization of the initial electrospun mats. These textured coatings are characterized by low liquid adhesion and anti-staining performance. Furthermore, the low friction coefficient and excellent scratch resistance make them attractive as solid lubricants. The inherent texture of the coatings positively affects their biocompatibility. In fact, they are able to promote the proliferation and differentiation of myoblast stem cells. Optically-transparent and biocompatible coatings that simultaneously possess characteristics of low water contact angle hysteresis, low friction and mechanical robustness can find application in a wide range of technological sectors, from the construction and automotive industries to electronic and biomedical devices.

Human recombinant elastin-like protein coatings for muscle cell proliferation and differentiation.

Recombinant proteins represent a new and promising class of polymeric materials in the field of biomaterials research. An important model for biomaterial design is elastin, the protein accounting for the elasticity of several tissues. Human elastin-like polypeptides (HELPs) have been developed as recombinant versions of elastin with the purpose of enhancing some peculiar characteristics of the native protein, like self-assembling. In this paper, we report on a comparative study of rat myoblasts response to coatings based on two different HELP macromolecules, with respect to control cultures on bare cell culture polystyrene and on a standard collagen coating. Cell behavior was analyzed in terms of adhesion, proliferation and differentiation. The collected data strongly suggest the use of HELPs as excellent biomaterials for tissue engineering and regenerative medicine applications.

Proliferation and skeletal myotube formation capability of C2C12 and H9c2 cells on isotropic and anisotropic electrospun nanofibrous PHB scaffolds.

This study aims at investigating the behavior in terms of the proliferation and skeletal muscle differentiation capability of two myoblastic cell lines, C2C12 and H9c2, on both isotropic and anisotropic electrospun nanofibrous poly(hydroxybutyrate) (PHB) scaffolds, as well as on PHB films and polystyrene controls. After a careful characterization of the matrices in terms of surface morphology, surface roughness and mechanical properties, the proliferation rate and the capability of the two cell lines to form skeletal myotubes were evaluated. Genetic analyses were also performed in order to assess the differentiation level of the cells on the different substrates. We demonstrated that the aligned nanofibrous mesh decreases the proliferation activity and provides a higher differentiative stimulus. We also clarified how the nanofibrous substrate influences myotube formation, and quantified a series of myotube-related parameters for both C2C12 and H9c2 cells.

Nanostructured, highly aligned poly(hydroxy butyrate) electrospun fibers for differentiation of skeletal and cardiac muscle cells.

The influence of novel nanostructured anisotropically electrospun poly(hydroxy butyrate) matrices on skeletal and cardiac muscle-like cell proliferation and differentiation was investigated, in comparison with isotropic and no-topographically cues-provided substrates. After the matrix characterization, in terms of surface SEM imaging and mechanical properties, cell differentiation on the different substrates was evaluated. Myogenin and F-actin staining at several differentiation time-points suggested that aligned nanofibers promote differentiation of both cell types. Moreover, quantitative parameters for each cell line are provided to clarify which aspects of the differentiation process are influenced by the different matrix topographies.