Synthesised Conductive/Magnetic Composite Particles for Magnetic Ablations of Tumours.

Ablation is a clinical cancer treatment, but some demands are still unsatisfied, such as electromagnetic interferences amongst multiple ablation needles during large tumour treatments. This work proposes a physical synthesis for composite particles of biocompatible iron oxide particles and liquid metal gallium (Ga) with different alternative-current (AC)-magnetic-field-induced heat mechanisms of magnetic particle hyperthermia and superior resistance heat. By some imaging, X-ray diffraction, and vibrating sample magnetometer, utilised composite particles were clearly identified as the cluster of few iron oxides using the small weight ratio of high-viscosity liquid metal Ga as conjugation materials without surfactants for physical targeting of limited fluidity. Hence, well penetration inside the tissue and the promotion rate of heat generation to fit the ablation requirement of at least 60 °C in a few seconds are achieved. For the injection and the post-injection magnetic ablations, the volume variation ratios of mice dorsal tumours on Day 12 were expressed at around one without tumour growth. Its future powerful potentiality is expected through a percutaneous injection.

Design and Application of a Flexible Blood Oxygen Sensing Array for Wearable Devices.

The performance of portable or wearable oximeters is affected by improper movement or wear, which causes an error in the blood oxygen concentration calculation. The error comes from external incident stray light or light leakage caused by the improper fit of the sensor to the skin. This study aimed to develop a flexible blood oxygen sensing system with a 3 × 3 array that uses a reflective-type blood oxygen sensing chip to sequentially measure the blood oxygen levels at nine locations through a time division pulse modulation method. Each sensing chip has light transmission and receiving parts. A flip chip package was used to integrate the sensing chip, and a flexible parylene substrate that could fit the curvature of the wrist and locate the array of photo diodes around the radial artery of the wrist was used. By scanning the sensor array in dynamic behavior, the correct light intensity can be extracted to obtain the blood oxygen concentration and prevent errors due to improper fit or sensor movement during exercise.

Highly efficient magnetic ablation and the contrast of various imaging using biocompatible liquid-metal gallium.

BACKGROUND: Although the powerful clinical effects of radiofrequency and microwave ablation have been established, such ablation is associated with several limitations, including a small ablation size, a long ablation time, the few treatment positioning, and biosafety risks. To overcome these limitations, biosafe and efficient magnetic ablation was achieved in this study by using biocompatible liquid gallium as an ablation medium and a contrast medium for imaging. RESULTS: Magnetic fields with a frequency (f) lower than 200 kHz and an amplitude (H) × f value lower than 5.0 × 109 Am-1 s-1 were generated using the proposed method. These fields could generate an ablation size of 3 cm in rat liver lobes under a temperature of approximately 300 °C and a time of 20 s. The results of this study indicate that biomedical gallium can be used as a contrast medium for the positioning of gallium injections and the evaluation of ablated tissue around a target site. Liquid gallium can be used as an ablation medium and imaging contrast medium because of its stable retention in normal tissue for at least 3 days. Besides, the high anticancer potential of gallium ions was inferred from the self-degradation of 100 µL of liquid gallium after around 21 days of immersion in acidic solutions. CONCLUSIONS: The rapid wireless ablation of large or multiple lesions was achieved through the simple multi-injection of liquid gallium. This approach can replace the currently favoured procedure involving the use of multiple ablation probes, which is associated with limited benefits and several side effects. METHODS: Magnetic ablation was confirmed to be highly efficient by the consistent results obtained in the simulation and in vitro tests of gallium and iron oxide as well as the electromagnetic specifics and thermotherapy performance comparison detailed in this study Ultrasound imaging, X-ray imaging, and magnetic resonance imaging were found to be compatible with the proposed magnetic ablation method. Self-degradation analysis was conducted by mixing liquid gallium in acidic solutions with a pH of approximately 5-7 (to imitate a tumour-containing microenvironment). X-ray diffraction was used to identify the gallium oxides produced by degraded gallium ions.

Potential-induced sonoelectrochemical graphene nanosheets with vacancies as hydrogen peroxide reduction catalysts and sensors.

Defective graphene nanosheets (dGN4V) with 5-9, 5-8-5, and point defects were synthesised by a sonoelectrochemical method, where a potential of 4 V (vs. Ag/AgCl) was applied to drive the rapid intercalation of phosphate ions between the layers of the graphite foil as a working electrode. In addition to these vacancies, double vacancy defects were also created when the applied potential was increased to 8 V (dGN8V). The defect density of dGN8V (2406 µm-2) was higher than that of dGN4V (1786 µm-2). Additionally, dGN8V and dGN4V were applied as catalysts for the hydrogen peroxide reduction reaction (HPRR). The mass activity of dGN8V (1.31 × 10-2 mA·µg-1) was greater than that of dGN4V (1.17 × 10-2 mA·µg-1) because of its high electrochemical surface area (ECSA, 1250.89 m2·g-1) and defect density (ND, 2406 µm-2), leading to low charge transfer resistance on the electrocatalytic interface. The ECSA and ND of dGN4V were 502.7 m2·g-1 and 1786 µm-2, respectively. Apart from its remarkable HPRR activity, the cost-effective dGN8V catalyst also showed potential as an amperometric sensor for the determination of H2O2.

Technology for 3D System Integration for Flexible Wireless Biomedical Applications.

This paper presents a new 3D bottom-up packing technology for integrating a chip, an induction coil, and interconnections for flexible wireless biomedical applications. Parylene was used as a flexible substrate for the bottom-up embedding of the chip, insulation layer, interconnection, and inductors to form a flexible wireless biomedical microsystem. The system can be implanted on or inside the human body. A 50-µm gold foil deposited through laser micromachining by using a picosecond laser was used as an inductor to yield a higher quality factor than that yielded by thickness-increasing methods such as the fold-and-bond method or thick-metal electroplating method at the operation frequency of 1 MHz. For system integration, parylene was used as a flexible substrate, and the contact pads and connections between the coil and chip were generated using gold deposition. The advantage of the proposed process can integrate the chip and coil vertically to generate a single biocompatible system in order to reduce required area. The proposed system entails the use of 3D integrated circuit packaging concepts to integrate the chip and coil. The results validated the feasibility of this technology.

Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures.

We propose an electrostatically-actuated microelectromechanical digital-to-analog converter (M-DAC) device with low actuation voltage. The spring structures of the silicon-based M-DAC device were monolithically fabricated using parylene-C. Because the Young's modulus of parylene-C is considerably lower than that of silicon, the electrostatic microactuators in the proposed device require much lower actuation voltages. The actuation voltage of the proposed M-DAC device is approximately 6 V, which is less than one half of the actuation voltages of a previously reported M-DAC equipped with electrostatic microactuators. The measured total displacement of the proposed three-bit M-DAC is nearly 504 nm, and the motion step is approximately 72 nm. Furthermore, we demonstrated that the M-DAC can be employed as a mirror platform with discrete displacement output for a noncontact surface profiling system.

The mechanisms of carnosic acid attenuates tumor necrosis factor-α-mediated inflammation and insulin resistance in 3T3-L1 adipocytes.

SCOPE: Insulin resistance has been linked to a low-grade chronic inflammatory response. Carnosic acid (CA), which is found in rosemary, has been reported to have antioxidant, anti-inflammation, and anti-adipogenic properties. Here, we examined the effects of CA on inflammation and insulin resistance in 3T3-L1 adipocytes treated with tumor necrosis factor-α (TNF-α). METHODS AND RESULTS: CA attenuated the TNF-α-induced mRNA expression of inflammatory genes, including IL-6 and monocyte chemoattractant protein-1. CA also attenuated the TNF-α-mediated activation of extracellular signal-regulated kinase, c-Jun NH2-terminal kinase, and c-Jun; the phosphorylation of inhibitor-κB (IκB) kinase (IKK)α/ß, the phosphorylation and degradation of IκBα, the nuclear translocation of p65, and the DNA-binding activity of NF-κB and AP-1. CA or PP242 (an mTOR inhibitor) suppressed the TNF-α-induced protein expression of mTOR, p70S6K, eIF4E, and IL-6. Moreover, CA attenuated the TNF-α-mediated suppression of peroxisome proliferator-activated receptor γ, adiponectin, and adipocyte protein 2. CA reversed the TNF-α-mediated suppression of insulin-stimulated glucose uptake and the phosphorylation of Tyr(632) insulin receptor substrate-1 (IRS-1), Akt, and FoxO1, but decreased the TNF-α-induced phosphorylation of Ser(307) IRS-1 and total FoxO1. CONCLUSION: CA attenuates TNF-α-mediated inflammation via inhibition of NF-κB and AP-1 pathways and insulin resistance via Akt-dependent FoxO1 signaling in 3T3-L1 adipocytes.