A Miniature Fiber Optic Refractive Index Sensor Built in a MEMS-Based Microchannel

A small, highly sensitive, and electromagnetic interference (EMI)-immune refractive index (RI) sensor based on the Fabry-Perot (FP) interferometer is presented. The sensor’s FP cavity was fabricated by aligning two metal-deposited, single-mode optical fiber endfaces inside a microchannel on a silicon chip. The mirrors on the fiber endfaces were made of thermal-deposited metal films, which provided the high finesse necessary to produce a highly sensitive sensor. Microelectromechanical systems (MEMS) fabrication techniques, specifically photolithography and deep dry etching, were used to precisely control the profile and depth of the microchannel on the silicon chip with an accuracy of 2 μm. The RI change within the FP cavity was determined by demodulating the transmission spectrum phase shift. The sensitivity and finesse of the transmission spectrum were controlled by adjusting the cavity length and the thickness of the deposited metal. Our experimental results showed that the sensor’s sensitivity was 665.90 nm/RIU (RI Unit), and the limit of detection was 6 × 10−6 RIU. Using MEMS fabrication techniques to fabricate these sensors could make high yield mass production a real possibility. Multiple sensors could be integrated on a single small silicon chip to simultaneously measure RI, temperature, and biomolecule targets

Surface-Enhanced Raman Scattering Sensor on an Optical Fiber Probe Fabricated with a Femtosecond Laser

A novel fabrication method for surface-enhanced Raman scattering (SERS) sensors that used a fast femtosecond (fs) laser scanning process to etch uniform patterns and structures on the endface of a fused silica optical fiber, which is then coated with a thin layer of silver through thermal evaporation is presented. A high quality SERS signal was detected on the patterned surface using a Rhodamine 6G (Rh6G) solution. The uniform SERS sensor built on the tip of the optical fiber tip was small, light weight, and could be especially useful in remote sensing applications

Identification and characterization of NVP-BKM120, an orally available pan class I PI3-Kinase inhibitor

The PI3K/Akt/mTor signaling pathway plays an important role in controlling cell growth, proliferation and survival. Following the discovery of NVP-BEZ235, our first dual pan-PI3K/mTOR clinical compound, we sought to identify additional PI3K inhibitors from different chemical classes with more stringent selectivity profiles. The key to achieve these objectives was to couple a structure-based design approach with intensive pharmacological evaluation of selected compounds during the medicinal chemistry optimization process. Here we report on the biological characterization of the 2-morpholino pyrimidine derivative pan-PI3K inhibitor NVP-BKM120. This compound inhibits all four Class I PI3K isoforms in biochemical assays with at least 50-fold selectivity (relative to p110) against other protein kinases. The compound is also active against the most common somatic PI3K mutations but does not significantly inhibit the related Class III (Vps34) and Class IV (mTOR, DNA-PK) PI3K kinases. Consistent with its mechanism of action, NVP-BKM120 decreases the cellular levels of p-Akt in mechanistic models and relevant tumor cell lines, as well as downstream effectors in a concentration dependent and pathway specific manner. Tested in a panel of 353 cell lines, NVP-BKM120 exhibited preferential inhibition of tumor cells bearing PIK3CA mutations, in contrast to either KRAS or PTEN mutant models. NVP-BKM120 shows dose-dependent in vivo pharmacodynamic activity as measured by significant inhibition of p-Akt and tumor growth inhibition in mechanistic xenograft models. Moreover, NVP-BKM120 demonstrates synergistic advantages when combined with either targeted therapy agents such as MEK or HER2 inhibitors or with cytotoxic agents such as Docetaxel or Temozolomide. The pharmacological, biological and preclinical safety profile of NVP-BKM120 supports its clinical development and the compound is currently undergoing Phase II clinical trials in cancer patients