Spray-printing and pre-designed mask was combined to rapidly pattern liquid metal electronics on skin as physiological testing devices.

Background We proposed a method of using electrical stimulation for treatment of malignant melanoma through directly spray-printing liquid metal on skin as soft electrodes to deliver low intensity, intermediate frequency electric fields. Methods With patterned conductive liquid metal components on mice skin and under assistance of a signal generator, a sine wave electrical power with voltage of 5 V and 300 kHz could be administrated on treating malignant melanoma tumor. Findings The experiments demonstrated that tumor volume was significantly reduced compared with that of the control group. Under the designed parameters (signal: sine wave, signal amplitude Vpp: 5 V and Vpp: 4 V, frequency: 300 kHz) of Tumor treating fields (TTFields) with the sprayed liquid metal electrode, four mice tumor groups became diminishing after 1 week of treatment. The only device-related side effect as seen was a mild to moderate contact dermatitis underneath the field delivering electrodes. The SEM images and pathological analysis demonstrated the targeted treating behavior of the malignant melanoma tumor. Further, thermal infrared imaging experiments indicated that there occur no evident heating effects in the course of treatment. Besides, the liquid metal is easy to remove through medical alcohol. Conclusions Tumor treating fields through liquid metal electrode could offer a safe, straightforward and effective treatment modality which evidently slows down tumor growth in vivo. These promising results also raised the possibility of applying spray-printing TTFields as an easy going physical way for future cancer therapy.

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In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO 3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

Pervasive detection of blood glucose is rather critical for the real-time disease diagnosis which would provide valuable guidance for treatment planning. Here, we established a health care platform for this purpose through incorporating the glucose detection with liquid metal printed sensor and the smart phone monitoring system together. The liquid metal ink composed of bismuth indium stannic (BIS) alloy was identified as an appropriate sensor material to be quickly written or printed on polyvinyl chloride (PVC) substrate at around 59 °C to form desired electrodes. It thus eliminated the complicated procedures as usually required in conventional sensor fabrication strategies. The alloy electrodes were characterized via cyclic voltammetry to demonstrate their practical functionality. Further, unlike using the commonly adopted glucometer, a smart phone was developed as the data acquisition and display center to help improve the portability and ubiquitous virtue of the detection system. Glucose solution in different concentrations was assayed via this platform. It was shown that there is a good linear relationship between the concentration and the integral value of the curve recorded by the mobile phone, which confirms the feasibility of the present method. This quantitative point-of-care system has pervasive feature and is expected to be very useful for future low-cost electrochemical detection.