Search

The extracellular matrix provides a structural foundation for cells while also providing biophysical and biochemical signals that guide and influence cell migration. Previous studies have demonstrated that factors such as topography, material composition, and surface energy can significantly influence the migratory behaviors of cells. However, the relationship between surface energy and cell migration on various surfaces is not well understood. To investigate this, we fabricated polydimethylsiloxane (PDMS) platforms featuring nanopillars, as well as silicon oxide (SiOx) and titanium oxide (TiOx) surface coatings. The study examined the cells' migration speed, morphology, and spreading in relation to the different surface properties and surface energies. Cells exhibited distinctive migration behaviors on the PDMS platforms with nanopillars and various surface coatings. In contrast to the flat PDMS, cells cultured on the SiOx and TiOx coatings exhibited less elongated morphologies, decreased mobility, and larger overall cell areas. Specifically, cells had the smallest cell elongation on the SiOx surface and the lowest migration speed on platforms coated with TiOx. In contrast, cells cultured on the nanopillar surface exhibited increased migration speeds, more elongated morphologies, and smaller overall cell areas. These findings suggest that cell migration behavior is obviously affected by the existence of nanopillars or the type of surface coating, which in turn is relevant to the surface energy of the platform. Elucidating the relationships between various surface properties, resulting cell migration behaviors, and overall surface energy could enable improved control over cell migration in a bionic platform designed to promote tissue regeneration and repair. [ABSTRACT FROM AUTHOR]

A metasurface array for electromagnetic (EM) energy harvesting for Wi-Fi bands is presented in this paper; the metasurface array consists of a metasurface unit, a rectifier, and a load resistor. Each row of unit cells in the array is interconnected to form an energy transfer channel, which enables the transfer and concentration of incident power. Furthermore, at the terminal of the channel, a single series diode rectifier circuit and a load resistor are integrated in a coplanar manner. It is used to rectify the energy in Wi-Fi bands and enables DC energy harvesting across the load. Finally, a 5 × 7 prototype of the metasurface array is fabricated and measured for the verification of the rationality of the design. Testing in an anechoic chamber shows that the prototype achieves a 72% RF-DC efficiency at 5.9 GHz when the available incident power is about 7 dBm. [ABSTRACT FROM AUTHOR]

A compact ultra-wideband and flexible MEMS monopole antenna fed by coplanar waveguide(CPW) was proposed, which has the characteristics of simple structure, light quality, ease of integration and flexible bending. The antenna used a PDMS material with outstanding flexibility and great self-recovery as its substrate. The disc shaped metal radiation structure was designed on the side of the flexible substrate, and the CPW structure was integrated with the antenna on the same side of the substrate. In the experiment, it is proved that the combined treatment of oxygen plasma and SDS can effectively improve the adhesion effect of photoresist and PDMS surface. The MEMS monopole flexible antennas fed by CPW were separately fabricated on the PDMS flexible substrate by metal lift-off process based on AZ6130，RZJ304 and AZ5214E photoresist, and the performances and the lift-off difficulty of the antennas fabricated based on different photoresists were compared. The frequency band of the antenna is 3.3 GHz to 5 GHz, of which the impedance matching is perfect and the radiation directivity is stable. It can be applied to 5G communication system, and also provides a reference for the research of flexible antenna.

To study the relationship between the performance and the size of the filter, a W band rectangular waveguide bandpass filter with cross-coupling structure is designed. The cross-coupling structure reduces the rectangular coefficient by 25.7% and enhances out of band rejection. The simulation results of the three kinds of center frequency models show the scale effect between the center frequency and the structure size. The parameters of the filter are analyzed by HFSS software. The results show that the center frequency is mainly controlled by the size of the cavity, the coupling structure mainly affects the loss of the filter and the thickness of the diaphragm can control the passband bandwidth. The 90 GHz filter model is processed and tested, and the test results are mainly agreement with the simulated results.