Silk Fibroin-Based Hydrogel for Multifunctional Wearable Sensors

The flexible wearable sensors with excellent stretchability,high sensitivity and good biocompatibility are significantly required for continuously physical condition tracking in health management and rehabilitation monitoring.Herein,we present a high-performance wearable sensor.The sensor is prepared with nanocomposite hydrogel by using silk fibroin(SF),polyacrylamide(PAM),polydopamine(PDA)and graphene oxide(GO).It can be used to monitor body motions(including large-scale and small-scale motions)as well as human electrophysiological(ECG)signals with high sensitivity,wide sensing range,and fast response time.Therefore,the proposed sensor is promising in the fields of rehabilitation,motion monitoring and disease diagnosis.

Strong and Tough PAm/SA Hydrogel with Highly Strain Sensitivity

The hydrogel is a preferred material for flexible wearable sensors.In practical application,it should have high-efficiency mechanical toughness and self-healing performance.Besides,hydrogel requires good affinity and adhe-sion because of its contact with the skin.In this experiment,we made an ultra-tough hydrogel with excellent cell affinity and adhesion.We used sodium alginate(SA)and polyacrylamide(PAm)mixture as a flexible base fluid.Polydopamine reduce graphene oxide(prGO)was used as conductive nanofiller,and then PAm-prGO-SA semi-interpenetrating network hydrogel was formed through Am radical polymerization.The presence of prGO endows the hydrogels with excellent electrical conductivity.Simultaneously,some non-reduced GO forms non-covalent cross-links with PAm,SA,and Polydopamine(PDA)in the hydrogel network.The stress of PAm-prGO-SA hydrogel can reach 750 KPa,and the strain is 900%.The hydrogel,combined with its excellent electrical,mechanical properties,and biocompatibility,is expected to be applied in portable,remote,and real-time health monitoring systems.

Development of Digital-Controlled Measuring Instrument for Hearing

A digital-controlled measuring instrument for hearing, which is mainly composed of STC11F16EX, AD9833, ISD400416MS and LM1972, is introduced in this paper. It may output highly accurate and purified sine signal whose frequency and amplitude are controlled by digital data. Specially, the displaying number of decibel is equal to actual number of decibel because that frequency response of earphone is corrected through software of microcontroller. Additionally, touching buttons, which is simple and convenience to use, is selected. Hence this instrument is convenient to measure and teach about hearing specially, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science.

A Promising Wound Dressing from Regenerated Silk Fibroin Sponge with Sustain-ed Release of Silver Nanoparticles

A silk fibroin(SF)spongy wound dressing incorporated with silver nanoparticles(Ag-NPs)was developed for biomedical applications.Ag-NPs were efficiently synthesized in situ via ultra violet(UV)with AgNO_(3) as precursor and silk fibroin as reducing and protecting agent,respectively.After lyophilization,the formed silk fibroin spongy wound dressing(SFWD)exhibited polyporous morphology and inner lamellae structures,with uniform dispersion of Ag-NPs.The porous structure provided SFWD with the ability to absorb tissue exudatealmost 6 times of its own weight,which could guarantee the sustained release of Ag-NPs.By methanol treatment,SFWD showed much improved mechanical properties and more stable to protease XIV.The cyto-compatibility of SFWD was supported by normal adherence and proliferation of NIH3T3 fibroblasts in sponges extracting culture medium.More important,the SFWD showed significant growth inhibition in both plate culture assays and bacterial suspension assays,with Gram-positive(Staphylococcus aureus)and Gram-negative(Pseudomonas aeruginosa and Escherichia coli).In a cutaneous excisional mouse model,the average healing rates of SFWD was significantly higher than control and commercial bandages.The hematoxylin-eosin(HE)staining results of the wound section also showed that SFWD could recruit more cells and promote tissue formation on the wound edges.

Liquid Crystal Biosensor Based on Cd²⁺Inducing the Bending of PS-Oligo for the Detection of Cadmium

In this study, a novel liquid crystal (LC) biosensor was developed for the highly sensitive and selective detection of Cd2+ based on Cd2+ inducing the bending of PS-oligo. This strategy makes use of the DNA conformational change to enhance the disruption of orientation of LC leading to an amplified optical signal. DNA containing-SH was bound on the glass slide of the LC cell modified with the DMOAP/APTES. The DMOAP can effectively induce the homeotropic alignment of LC. In the presence of Cd2+, Cd2+ can induce DNA to bend and become a 2 nm spherical structure, which can greatly disrupt the orientational arrangement of LC, resulting in the correspond changes of the optical image of LC cell birefringent under the polarizing microscope. When the Cd2+ concentration is low to 0.1 nM, the optical signal of LC biosensor has an obvious change. But in the absence of Cd2+, there is no orientational response of LC and the optical image under the polarizing microscope is still a uniform dark background. Thus, this LC sensing method has a sensitive and clear distinction between positive and negative results and offers a highly sensitive detection of Cd2+ with a low detection limit down to 0.1 nM.

Design and application of computer software for collecting color data about urine reagent strips

Urine analysis is one of the most common and useful assay means in clinic for diagnose disease, especially urinary system disease and dry chemistry method is the most convenient, common and low cost about urine analysis. To expediently and efficiently analyze the corresponding relationships between different color data and semi-quantitative results about every urine item with dry chemistry way, in this paper, the design and application of effective software that may be used to collect color data about urine reagent strips are presented. First, we introduce the design procedure of this software. Second, its realization of design is given. Third, several application examples about collecting RGB original data by RS232 interface are shown. Then, RGB original data can be visually displayed by waveforms or curves and the data of cursor position may also be given. From the examples, we could confidently draw a conclusion that it is very convenient and effective to study on the laws of color variation about reagent pieces on reagent strip and it has met our original designed demands.

Colorimetric Detection of Lead Ion Based on Gold Nanoparticles and Lead-Stabilized G-Quartet Formation

In this report, we present a method for the detection of Pb2+ based on the different adsorption capacity on the surface of gold nanoparticles (AuNPs) between ssDNA (single-stranded DNA) and G-quartet. In the absence of Pb2+, the DNA oligonucleotides probe, which is guanine-rich ssDNA, can be adsorbed on the surface of AuNPs protecting them from aggregation. After adding Pb2+, the DNA oligonucleotides probe can specifically form compact G-quartet, which can induce the aggregation of unmodified AuNPs, especially after adding NaCl aqueous solution. Consequently, the color turns from red to blue. Pb2+ can be detected by colorimetric response of AuNPs;its detection limit can reach 5 μM only observed by naked eyes. Most metal ions have no interferences, and the interference of Cu2+ can be effectively eliminated by adding cysteine. It provides a simple and effective colorimetric sensor for on-site and real time detection of Pb2+.

Design and Application of Software for Generating Simulated Signal Data

Simulated signal, produced by digital to analog converter, is important and necessary in many fields, such as electronic experiment, equipment debugging and maintenance, especially, in medical area. In this paper, the design and application of an effective software which may be used to generate simulated signal data by special wave picture obtained by scanner or drawing software are presented. First, we introduce how to realize producing needed data that meet the given conditions including amplitude, samples and resolution by this software. Second, the method and steps of getting the stimulated signal data from wave figure file is given. Third, an example of application about this software to generate simulated physiological signal data is shown. Then, the data are put into use and by digital to analog converter, an idea stimulated signal is produced. Therefore, with full confidence, we could draw a conclusion that it is very convenient and effective to get needed data for digital to analog conversion to generate all kinds simulated signal with a novel method.

Development of a Double-Channel Medical Signal Generator Based on STM32 with High Performance

An open-ended and multifunctional double-channel signal generator, which based on a 32 bits monolithic integrated microcomputer, highly integrated device and LCD, is introduced in this paper. The instrument is composed of micro-computer STM32F103RD and some integrated chips (IC), which includes programmable waveform generators-AD9833 with highly frequency and phase precision. As a result, this signal generator may output not only double channels accurate sine, square or triangle waveforms with digital-controlled frequency and phase at the same time, but also many kinds of physiological signals that can be modified by USB connection with well open property. Therefore, it is convenient to measure and teach about hearing, research and study on frequency characteristic of human ear and impedance characteristic of human body in medical science. In addition, it is also very easy in experiment and research of college and medical physics for using double channels sine signal to show synthesis of two simple harmonic vibrations under different frequency, phase difference and direction, such as beat pattern and Lissajous figures. Thus it has many merits, such as the small volume, stable property, simple operation, visual display and so on. Consequently, it can be widely used in researching, teaching, debugging and maintaining.