The ability to externally stimulate gold nanoparticles (GNPs) that are linked to drugs can improve targeted drug delivery to help patients with Parkinson’s disease to increase the activity levels of their basal ganglia to regain motor skills that were once lost. This paper analyzes 5 nm GNPs due to their biocompatibility and ability to cross the blood-brain barrier (BBB). Studies have shown GNPs heat up when exposed to radiofrequency (RF) electromagnetic fields which could be used to release dopamine-related drugs directly in a patient’s basal ganglia to increase activity. However, GNP stimulation often requires a high power output which could damage tissues. A series of methods were used to first characterize the GNPs to ensure the size and viability of the sample. Then, different stimulation tests were run to evaluate the temperature change of GNPs to determine if stimulation is possible in a frequency range that does not require a high power output. The most successful stimulation method utilized a waveguide, which was able to consistently heat GNPs 0.4 C in 15 minutes more than the negative control. The methodology was then tested within the brain of a perfused rat by using magnetic resonance thermometry (MRT). Two scans were taken at different times to solve for the differential pixel value to evaluate whether the brain cooled down over time after being theoretically stimulated initially. While the initial results of these scans were inconclusive, there was much to be improved throughout the process, warranting further research.
The development of fMREIT for the direct detection of neural activity using conductivity contrast in in vivo settings has been the focus of the research work presented here. An in vivo animal model was developed to detect neural activity initiated changes in neuronal membrane conductivities under external electrical current stimulation. Neural activity was induced in somatosensory areas I (SAI) and II (SAII) by applying electrical currents between the second and fourth digits of the rodent forepaw. The in vivo animal model involved the use of forepaw stimulation to evoke somatosensory neural activations along with hippocampal fMREIT imaging currents contemporaneously applied under magnetic field strengths of 7 Tesla. Three distinct types of fMREIT current waveforms were applied as imaging currents under two inhalants – air and carbogen. Active regions in the somatosensory cortex showed significant apparent conductivity changes as variations in fMREIT phase (φ_d and ∇^2 φ_d) signals represented by fMREIT activation maps (F-tests, p <0.05). Consistent changes in the standard deviation of φ_d and ∇^2 φ_d in cortical voxels contralateral to forepaw stimulation were observed across imaging sessions. These preliminary findings show that fMREIT may have the potential to detect conductivity changes correlated with neural activity.
A cardiac pacemaker is one of the longest and most widely used implantable devices and the wireless technology is the most widely used with it for easy acquisition of vital signs and rapid disease diagnosis without clinical surgery. But the conventional pacemakers with some wireless technology face some essential complications associated with finite battery life, ultra-vein pacing leads, and risk of infection from device pockets and leads. To solve these problems, wireless cardiac pacemaker operating in fully-passive modality is proposed and demonstrates the promising potential by realizing a prototype and functional evaluating.