Effect of Magnesium on the Mechanical and Bioactive Properties of Biphasic Calcium Phosphate

Incorporation of trace elements into calcium phosphate structure is of great interest for the development of artificial bone implants. Biphasic calcium phosphate (BCP) composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have been synthesized in the presence of magnesium (5 M% - 20 M%) by gel method under physiological conditions. Crystallization of Mg-BCP in the gel medium mimics the Mg intake in the human body. Powder X-ray dif- fraction and Fourier transform infrared analyses confirmed that the Mg doping leads to the enrichment of β-TCP phase and suppresses the HA content in BCP. Nanoindentation studies indicate a significant decrease in hardness and elastic modulus values of BCP due to Mg doping. In vitro bioactivity study has confirmed the formation of apatite layer on the Mg doped samples making it suitable for bone replacement. The results suggest that the optimum Mg doping promotes the bioactivity which is perquisite for biomedical applications.

Tail nerve electrical stimulation-induced walking training promotes restoration of locomotion and electrophysiology in rats with chronic spinal cord injury

Functional recovery is the final goal in the treatment of spinal cord injury. However, to date, few treatment strategies have demonstrated significant locomotor improvement in animal experiments. By using tail nerve electrical stimulation (TANES) as an open-field locomotor training method combined with glial scar ablation and cell transplantation, we have successfully promoted locomotor recovery in rats with chronic spinal cord contusion injury. The purpose of the present study is to further investigate the mechanism of TANES and its effect on electrophysiology. Spinal cord segment T10 of female, adult Long-Evans rats was contused using the NYU impactor device with 25 mm height setting. After injury, rats were randomly divided into three groups. Group I was used as a control without any treatment, group II and group III were subjected to basic treatment including glial scar ablation and transplantation of olfactory lamina propria 6 weeks after injury, and group III received TANES-induced open-field locomotor training weekly after basic treatment. All animals were allowed to survive 22 weeks, except some rats which were transected. Basso, Beattie, and Bresnahan (BBB) open-field locomotor rating scale, horizontal ladder rung walking test, and electrophysiological tests were used to assess the restoration of functional behavior and conduction. Results showed that TANES significantly improves locomotor recovery and spinal cord conduction, reflex, as well as significantly reduces the occurrence of autophagia. Additionally, after transection, trained rats still maintained higher BBB score than that of control rats. This may be related to the activity-dependent plasticity promoted by TANES-induced locomotor training.

Role of Strontium on the Crystallization of Calcium Hydrogen Phosphate Dihydrate (CHPD)

Calcium hydrogen phosphate dihydrate (CHPD, CaHPO4· 2H2O) or brushite is found quite frequently in urinary calculi (stones). Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with and without adding ‘Sr’ as additive. In pure system, dicalcium phosphate anhydrous (DCPA, CaHPO4) or monetite and hydroxyapatite (HA, Ca5(PO4)3(OH)) grew along with brushite. The presence of Sr suppressed the formation of HA and enhanced the number and size of monetite crystals and changed the morphology of brushite crystals from needle shape to octopus-like shape. The samples were characterized by powder & single crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), Xray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) and thermal analyses (TG-DTA).

Effects of UV-, Visible-, Near-Infrared Beams in Three Therapy Resistance Case Studies of Fungal Skin infections

Fungal and bacterial diseases, directly infecting various parts of body, have received much attention in recent years. Bacterial infections, such as Tinea Pedis, Pityriasis versicolor and Mycetoma can secondarily occur in superficial fungal damaged skin. They often occur in immune compromised individuals including diabetics and patients with peripheral arterial diseases. Mycetoma infections can travel through the bloodstream affecting different organs. In this paper, we investigate the photo-inactivation of the pathogens causing Tinea Pedis, Pityriasis versicolor, and Mycetoma infections in three therapy resistant patients without photosensitizing drugs. We have used a combination of visible to near-infrared (VIS/NIR) laser beams in association with blue (B), red (R) and ultra-violet (UV) light emitted diodes (LEDs) with incident doses of 0.63 - 21.43 J/cm2. These beams have minimum side effects on the normal part of the skin. According to the physicians’ assessments, all case study patients achieved an observable progress such as decreases in inflammatory lesions, rapid process of wound healing and scars improvements. Side effects such as inflammation, crusting, or hypopigmentation were not observed. The presented irradiation protocol may be a valuable complementary treatment for patients suffering from fungal and bacterial skin infections.

Fabrication and in vivo 2-photon microscopy validation of transparent PEDOT:PSS microelectrode arrays

Transparent microelectrode arrays enable simultaneous electrical recording and optical imaging of neuronal networks in the brain.Electrodes made of the conducting polymer poly(3,4-ethylenedioxythiophene)doped with polystyrene sulfonate(PEDOT:PSS)are transparent;however,device fabrication necessitates specific processes to avoid deterioration of the organic material.Here,we present an innovative fabrication scheme for a neural probe that consists of transparent PEDOT:PSS electrodes and demonstrate its compatibility with 2-photon microscopy.The electrodes show suitable impedance to record local field potentials from the cortex of mice and sufficient transparency to visualize GCaMP6f-expressing neurons underneath the PEDOT:PSS features.The results validate the performance of the neural probe,which paves the way to study the complex dynamics of in vivo neuronal activity with both a high spatial and temporal resolution to better understand the brain.

Organic transistor platform with integrated microfluidics for in-line multi-parametric in vitro cell monitoring

Future drug discovery and toxicology testing could benefit significantly from more predictive and multi-parametric readouts from in vitro models.Despite the recent advances in the field of microfluidics,and more recently organ-on-a-chip technology,there is still a high demand for real-time monitoring systems that can be readily embedded with microfluidics.In addition,multi-parametric monitoring is essential to improve the predictive quality of the data used to inform clinical studies that follow.Here we present a microfluidic platform integrated with in-line electronic sensors based on the organic electrochemical transistor.Our goals are twofold,first to generate a platform to host cells in a more physiologically relevant environment(using physiologically relevant fluid shear stress(FSS))and second to show efficient integration of multiple different methods for assessing cell morphology,differentiation,and integrity.These include optical imaging,impedance monitoring,metabolite sensing,and a wound-healing assay.We illustrate the versatility of this multi-parametric monitoring in giving us increased confidence to validate the improved differentiation of cells toward a physiological profile under FSS,thus yielding more accurate data when used to assess the effect of drugs or toxins.Overall,this platform will enable high-content screening for in vitro drug discovery and toxicology testing and bridges the existing gap in the integration of in-line sensors in microfluidic devices.

Conducting polymer tattoo electrodes in clinical electro-and magneto-encephalography

Temporary tattoo electrodes are the most recent development in the field of cutaneous sensors.They have successfully demonstrated their performances in the monitoring of various electrophysiological signals on the skin.These epidermal electronic devices offer a conformal and imperceptible contact with the wearer while enabling good quality recordings over time.Evaluations of brain activity in clinical practice face multiple limitations,where such electrodes can provide realistic technological solutions and increase diagnostics efficiency.Here we present the performance of inkjet-printed conducting polymer tattoo electrodes in clinical electroencephalography and their compatibility with magnetoencephalography.The working mechanism of these dry sensors is investigated through the modeling of the skin/electrode impedance for better understanding of the biosignals transduction at this interface.Furthermore,a custom-made skin phantom platform demonstrates the feasibility of high-density recordings,which are essential in localizing neuropathological activities.These evaluations provide valuable input for the successful application of these ultrathin electronic tattoos sensors in multimodal brain monitoring and diagnosis.

Integrating flexible electronics for pulsed electric field delivery in a vascularized 3D glioblastoma model

Glioblastoma is a highly aggressive brain tumor,very invasive and thus difficult to eradicate with standard oncology therapies.Bioelectric treatments based on pulsed electric fields have proven to be a successful method to treat cancerous tissues.However,they rely on stiff electrodes,which cause acute and chronic injuries,especially in soft tissues like the brain.Here we demonstrate the feasibility of delivering pulsed electric fields with flexible electronics using an in ovo vascularized tumor model.We show with fluorescence widefield and multiphoton microscopy that pulsed electric fields induce vasoconstriction of blood vessels and evoke calcium signals in vascularized glioblastoma spheroids stably expressing a genetically encoded fluorescence reporter.Simulations of the electric field delivery are compared with the measured influence of electric field effects on cell membrane integrity in exposed tumor cells.Our results confirm the feasibility of flexible electronics as a means of delivering intense pulsed electric fields to tumors in an intravital 3D vascularized model of human glioblastoma.