A novel cantilever array-based bio-sensor was batch-fabricated with IC compatible MEMS technology for precise liver cancer bio-marker detection. A micro-cavity was designed in the free end of the cantilever for local antibody-immobilization, thus the adsorption of the cancer biomarker takes place only in the local region of the cantilever instead of the whole lever, and the effect of adsorption-induced k variation can be dramatically reduced. These structural features offer several advantages: high sensitivity, high throughput, high mass detection accuracy, and a portable system. In addition, an analytical model has been established to eliminate the effect of the adsorption-induced lever stiffness change and has been applied to the precise mass detection of the cancer biomarker AFP; the experimentally detected AFP antigen mass by the sensor(7.6 pg/m L) is quite close to the calculated one(5.5 pg/m L), two orders of magnitude better than those of the fully antibody-immobilized cantilever sensor. These approaches can promote real applications of the cantilever sensors in cancer diagnosis.
Rice-like Gd(OH)_(3)nanorods were successfully prepared through a facile and rapid microwave-hydrothermal synthesis method without using any surfactants or templates.X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,thermogravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),selected area electron diffraction(SAED)and energy-dispersive spectroscopy(EDS)were used to characterize the samples.Results show that the nanorods have an average length of 400 nm and an average diameter of 50 nm.The effects of reaction parameters such as reaction temperature and time on the preparation were briefly investigated.It is found that the crucial factor for the formation of rice-like Gd(OH)3nanorods is reaction time.When the rice-like Gd(OH)3nanorods was codoped with Yb^(3+)and Er^(3+),strong upconversion emissions could be observed under the excitation of 980-nm-laser,and the calculated CIE color coordinates falls within the yellow region,which may be potential candidate for optical materials.
Sn-rich Au–Sn solder bonding has been systematically investigated for low cost and low temperature wafer-level packaging of high-end MEMS devices.The AuSn2 phase with the highest Vickers-hardness among the four stable intermetallic compounds of the Au–Sn system makes a major contribution to the high bonding shear strength.The maximum shear strength of 64 MPa and a leak rate lower than 4.9×10-7 atm·cc/s have been obtained for Au46Sn54 solder bonded at 310 ℃.This wafer-level low cost bonding technique with high bonding strength can be applied to MEMS devices requiring low temperature packaging.
