Enabling 3D electrical stimulation of adipose-derived decellularized extracellular matrix and reduced graphene oxide scaffolds using graphene electrodes.

Notwithstanding the demonstrated benefits of electrical stimulation in enhancing tissue functionality, existing state-of-the-art electrostimulation systems often depend on invasive electrodes or planar designs. This work exploits the versatility of graphene to fabricate biocompatible electrodes for the three-dimensional electrical stimulation of neural stem cells. A conductive green graphene-based ink was formulated and screen-printed as the bottom and top electrodes in a bottom-less standard culture well plate.

3D nanofibrous frameworks with on-demand engineered gray and white matters for reconstructing the injured spinal cord.

Spinal cord injury (SCI) is a disruptive and heterogeneous medical condition affecting millions of patients worldwide. Due to the absence of medical treatments to effectively restore the lost sensorimotor and autonomic functions, there is an ongoing pursuit of scaffolds aiming to bridge the injured spinal area. Herein, a novel electrospinning modality to construct 3D nanofibrous frameworks (NFFs) in accordance with distinct spinal cord microenvironments is used to engineer a biomimetic hemicord.

Application of Adipose Extracellular Matrix and Reduced Graphene Oxide Nanocomposites for Spinal Cord Injury Repair.

Graphene-based materials (GBMs) hold strong promise to restore the spinal cord microenvironment and promote functional recovery after spinal cord injury (SCI). Nanocomposites consisting of reduced graphene oxide (rGO) and adipose tissue-derived extracellular matrix (adECM) are known to promote neuronal growth in vitro and to evoke a biocompatible response in vivo when implanted on top of the intact spinal cord. In this study, pristine adECM and adECM-rGO nanocomposites are implanted directly after hemisection SCI in rats.

Biocompatible adipose extracellular matrix and reduced graphene oxide nanocomposite for tissue engineering applications.

Despite the immense need for effective treatment of spinal cord injury (SCI), no successful repair strategy has yet been clinically implemented. Multifunctional biomaterials, based on porcine adipose tissue-derived extracellular matrix (adECM) and reduced graphene oxide (rGO), were recently shown to stimulate neural stem cell growth and differentiation. Nevertheless, their functional performance in clinically more relevant conditions remains largely unknown.

Effects of graphene oxide and reduced graphene oxide nanomaterials on porcine endothelial progenitor cells.

Graphene oxide (GO) and reduced graphene oxide (rGO) have been widely used in the field of tissue regeneration and various biomedical applications. In order to use these nanomaterials in organisms, it is imperative to possess an understanding of their impact on different cell types. Due to the potential of these nanomaterials to enter the bloodstream, interact with the endothelium and accumulate within diverse tissues, it is highly relevant to probe them when in contact with the cellular components of the vascular system.

Customizing 3D Structures of Vertically Aligned Carbon Nanotubes to Direct Neural Stem Cell Differentiation.

Neural tissue-related illnesses have a high incidence and prevalence in society. Despite intensive research efforts to enhance the regeneration of neural cells into functional tissue, effective treatments are still unavailable. Here, a novel therapeutic approach based on vertically aligned carbon nanotube forests (VA-CNT forests) and periodic VA-CNT micropillars produced by thermal chemical vapor deposition is explored.

Effects of Graphene Oxide and Reduced Graphene Oxide Nanostructures on CD4 Th2 Lymphocytes.

The activation of T helper (Th) lymphocytes is necessary for the adaptive immune response as they contribute to the stimulation of B cells (for the secretion of antibodies) and macrophages (for phagocytosis and destruction of pathogens) and are necessary for cytotoxic T-cell activation to kill infected target cells. For these issues, Th lymphocytes must be converted into Th effector cells after their stimulation through their surface receptors TCR/CD3 (by binding to peptide-major histocompatibility complex localized on antigen-presenting cells) and the CD4 co-receptor. After stimulation, Th cells proliferate and differentiate into subpopulations, like Th1, Th2 or Th17, with different functions during the adaptative immune response.

Benefits in the Macrophage Response Due to Graphene Oxide Reduction by Thermal Treatment.

Graphene and its derivatives are very promising nanomaterials for biomedical applications and are proving to be very useful for the preparation of scaffolds for tissue repair. The response of immune cells to these graphene-based materials (GBM) appears to be critical in promoting regeneration, thus, the study of this response is essential before they are used to prepare any type of scaffold. Another relevant factor is the variability of the GBM surface chemistry, namely the type and quantity of oxygen functional groups, which may have an important effect on cell behavior.

Mechanical writing of electrical polarization in poly (L-lactic) acid.

Stimuli responsive materials are found in a broad range of applications, from energy harvesters to biomolecular sensors. Here, we report the production of poly (L-lactic acid) (PLLA) thin films that exhibit a mechanical stress responsive behaviour. By simply applying a mechanical stress through an AFM tip, a local electrical polarization was generated and measured by Kelvin Probe Force Microscopy.

Functionalized-ferroelectric-coating-driven enhanced biomineralization and protein-conformation on metallic implants.

In the context of bone regeneration, it is important to have platforms that with appropriate stimuli can support the attachment and direct the growth, proliferation and differentiation of cells. In the orthopedic field, metals and alloys are still the dominant materials used as implants, though their bioinert character leads to failure or to the need for multiple revision procedures. To respond to this situation here we exploit an alternative strategy for bone implants or repairs, based on charge mediating signals for bone regeneration, envisaged as a type of biological micro-electromechanical system (BioMEM).

Investigation of The Cellular Response to Bone Fractures: Evidence for Flexoelectricity.

The recent discovery of bone flexoelectricity (strain-gradient-induced electrical polarization) suggests that flexoelectricity could have physiological effects in bones, and specifically near bone fractures, where flexoelectricity is theoretically highest. Here, we report a cytological study of the interaction between crack stress and bone cells. We have cultured MC3T3-E1 mouse osteoblastic cells in biomimetic microcracked hydroxyapatite substrates, differentiated into osteocytes and applied a strain gradient to the samples.

Electrically polarized PLLA nanofibers as neural tissue engineering scaffolds with improved neuritogenesis.

Tissue engineering is evolving towards the production of smart platforms exhibiting stimulatory cues to guide tissue regeneration. This work explores the benefits of electrical polarization to produce more efficient neural tissue engineering platforms. Poly (l-lactic) acid (PLLA)-based scaffolds were prepared as solvent cast films and electrospun aligned nanofibers, and electrically polarized by an in-lab built corona poling device.

Are lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) ferroelectrics bioactive?

The use of functional materials, such as ferroelectrics, as platforms for tissue growth in situ or ex situ, is new and holds great promise. But the usage of materials in any bioapplication requires information on biocompatibility and desirably on bioactive behavior when bone tissue engineering is envisaged. Both requirements are currently unknown for many ferroelectrics.