Characterization of SH-SY5Y neurons subject to 92kHz ultrasound stimulation / Caracterización de neuronas SH-SY5Y sujetas a estimulación por ultrasonido de 92 kHz

SUMMARY: Cellular microstructural changes due to ultrasound exposure are critical to understand and characterize in order to further the establishment of ultrasonics in cell and tissue engineering and medicine. In this study, neurite length, nuclear morphology, and cellular toxicity are assessed at varying intensities of 92 kHz ultrasound provided by a piezoceramic disk element and incident upon SH- SY5Y neurons in vitro. Findings suggest that stimulation increases neurite length up to 2.73 fold tested at α = 0.05 in an intensity dependent manner. Additionally, stimulation causes a statistically significant (α = 0.05) decrease in nuclear area and less elongated nuclei, by 1.78 fold and 1.38 fold respectively, also in an intensity dependent manner. For maximum transducer surface intensities ranging from 0 to 39.11 W/cm2, the toxicity of 92 kHz ultrasound is assessed and a nontoxic range is determined using Caspase-3 and Annexin V staining, in addition to Calcium imaging via Calcein-AM staining. Intensities of up to 1.6 W/cm2 are found to be nontoxic for the cells under the parameters used in this study.

RESUMEN: Los cambios micro estructurales celulares debidos a la exposición a los ultrasonidos son fundamentales para comprender y caracterizar el establecimiento de los ultrasonidos en la ingeniería y la medicina de células y tejidos. En este estudio, la longitud de las neuritas, la morfología nuclear y la toxicidad celular se evalúan a intensidades variables de ultrasonido de 92 kHz proporcionado por un elemento de disco piezocerámico e incidente sobre las neuronas SH-SY5Y in vitro. Los resultados sugieren que la estimulación aumenta la longitud de las neuritas hasta 2,73 veces probada a α = 0,05 de una manera dependiente de la intensidad. Además, la estimulación provoca una disminución estadísticamente significativa (α = 0,05) en el área nuclear y núcleos menos alargados, en 1,78 veces y 1,38 veces, respectivamente y también de una manera dependiente de la intensidad. Para intensidades máximas de la superficie del transductor que oscilan entre 0 y 39,11 W / cm2, se evaluó la toxicidad del ultrasonido de 92 kHz y se determinó un rango no tóxico mediante tinción con Caspasa-3 y Anexina V, además de imágenes de calcio mediante tinción con Calceína-AM. Se encontró que las intensidades de hasta 1.6 W / cm2 no son tóxicas para las células bajo los parámetros usados en este estudio.

Design and verification of microelectrode twisting machine / 生物医学工程学杂志

As an interface between external electronic devices and internal neural nuclei, microelectrodes play an important role in many fields, such as animal robots, deep brain stimulation and neural prostheses. Aiming at the problem of high price and complicated fabrication process of microelectrode, a microelectrode twisting machine based on open source electronic prototyping platform (Arduino) and three-dimensional printing technology was proposed, and its microelectrode fabrication performance and neural stimulation performance were verified. The results show that during the fabrication of microelectrodes, the number of positive twisting turns of the electrode wire should generally be set to about 1.8 times of its length, and the number of reverse twisting rings is independent of the length, generally about 5. Moreover, compared with the traditional instrument, the device is not only inexpensive and simple to manufacture, but also has good expandability. It has a positive significance for both the personalization and popularization of microelectrode fabrication and the reduction of experimental cost.

In vivo photorelease of GABA in the mouse cortex

Electrical stimulation has been used for more than 100 years in neuroscientific and biomedical research as a powerful tool for controlled perturbations of neural activity. Despite quickly driving neuronal activity, this technique presents some important limitations, such as the impossibility to activate or deactivate specific neuronal populations within a single stimulation site. This problem can be avoided by pharmacological methods based on the administration of receptor ligands able to cause specific changes in neuronal activity. However, intracerebral injections of neuroactive molecules inherently confound the dynamics of drug diffusion with receptor activation. Caged compounds have been proposed to circumvent this problem, for spatially and temporally controlled release of molecules. Caged compounds consist of a protecting group and a ligand made inactive by the bond between the two parts. By breaking this bond with light of an appropriate wavelength, the ligand recovers its activity within milliseconds. To test these compounds in vivo, we recorded local field potentials (LFPs) from the cerebral cortex of anesthetized female mice (CF1, 60-70 days, 20-30 g) before and after infusion with caged γ-amino-butyric-acid (GABA). After 30 min, we irradiated the cortical surface with pulses of blue light in order to photorelease the caged GABA and measure its effect on global brain activity. Laser pulses significantly and consistently decreased LFP power in four different frequency bands with a precision of few milliseconds (P < 0.000001); however, the inhibitory effects lasted several minutes (P < 0.0043). The technical difficulties and limitations of neurotransmitter photorelease are presented, and perspectives for future in vivo applications of the method are discussed.

ZigBee-based Wireless Neuro-Stimulator for Improving Stroke Recovery

Stroke is a leading cause of adult disability and the second-leading cause of death in Korea. It is also the third-leading cause of death in the United States, leading to a serious demand for new interventions to improve the quality of life in stroke survivors. To this end, direct cortical stimulation using an epidural electrode has been reported with promising results in animal and human studies, showing the potential for enhancing the recovery in chronic stroke patients. For optimal results, doctors must be able to modify the stimulation pattern as frequently as needed over a period of time for a given patient. However, severe aftereffects caused by stroke limit patients' activities, making regular doctor visits for treatment difficult. This study aims to develop a prototype of a telemedicine system to enhance stroke recovery by using a ZigBee-based wireless neuro-stimulator. The ZigBee is a stable platform for many low-power wireless applications. To allow stroke patients to remotely obtain neuro-stimulation treatments from their doctors, we connected the ZigBee to the internet. The system also allows doctors to personalize treatment based on the history of the stimulation parameters. The system developed here can also be beneficial as a common platform for a wide range of brain diseases and clinical care for which electric stimulation is used.