Wide Dynamic Range Specific Detection of Therapeutic Drugs by Photonic Crystal Microcavity Arrays

Abstract: Six orders of magnitude wide dynamic range (0.1ng/ml to over 100g/ml), label-free detection of gentamicin small molecules with silicon photonic crystal microcavity biosensors multiplexed by multimode interference power splitters was experimentally demonstrated. Detection specificity was confirmed. The devices were fabricated with CMOS compatible 193nm UV lithography process on a silicon-on-insulator (SOI) wafer. The device comprises a 1×4 MMI (multimode interference) power splitter that splits the input light into four optical paths. On each path, an L-type PC microcavity sensor with different sensitivity is located, namely L3, L13, L55 and L13 with defect holes. Before applying any target solution, resonance spectrum for each device was recorded and the resonance position was used as baseline. The chip is then incubated in target solution for 40 min. Several concentrations of the target were measured. After each incubation, the chip was washed with PBS and new spectra were tested and resonance positions were recorded. From the data points i

Wide Dynamic Range Sensing in Photonic Crystal Microcavity Biosensors Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/27/2015 Terms of Use: http://spiedl.org/terms

Abstract: Typical L-type photonic crystal (PC) microcavities have a dynamic range of approximately 3-4 orders of magnitude in biosensing. We experimentally demonstrated that multiplexing of PC sensors with different geometry can achieve a wide dynamic range covering 6 orders of magnitude. In several applications of biosensing, such as drug discovery and therapeutic drug monitoring, it is essential to have , and two-dimensional PC biosensors for chip-integrated microarray applications in proteomics We fabricated PCWs on silicon-on-insulator (SOI) devices with a 250nm top silicon layer, a 3μm buried oxide layer

Ultra Sensitivity Silicon-Based Photonic Crystal Microcavity Biosensors for Plasma Protein Detection in Patients with Pancreatic Cancer

Defect-engineered photonic crystal (PC) microcavities were fabricated by UV photolithography and their corresponding sensitivities to biomarkers in patient plasma samples were compared for different resonant microcavity characteristics of quality factor Q and biomarker fill fraction. Three different biomarkers in plasma from pancreatic cancer patients were experimentally detected by conventional L13 defect-engineered microcavities without nanoholes and higher sensitivity L13 PC microcavities with nanoholes. 8.8 femto-molar (0.334 pg/mL) concentration of pancreatic cancer biomarker in patient plasma samples was experimentally detected which are 50 times dilution than ELISA in a PC microcavity with high quality factor and high analyte fill fraction

New insight into the molecular mechanisms of the biological effects of DNA minor groove binders.

Bisbenzimides, or Hoechst 33258 (H258), and its derivative Hoechst 33342 (H342) are archetypal molecules for designing minor groove binders, and widely used as tools for staining DNA and analyzing side population cells. They are supravital DNA minor groove binders with AT selectivity. H342 and H258 share similar biological effects based on the similarity of their chemical structures, but also have their unique biological effects. For example, H342, but not H258, is a potent apoptotic inducer and both H342 and H258 can induce transgene overexpression in in vitro studies. However, the molecular mechanisms by which Hoechst dyes induce apoptosis and enhance transgene overexpression are unclear.To determine the molecular mechanisms underlying different biological effects between H342 and H258, microarray technique coupled with bioinformatics analyses and multiple other techniques has been utilized to detect differential global gene expression profiles, Hoechst dye-specific gene expression signatures, and changes in cell morphology and levels of apoptosis-associated proteins in malignant mesothelioma cells. H342-induced apoptosis occurs in a dose-dependent fashion and is associated with morphological changes, caspase-3 activation, cytochrome c mitochondrial translocation, and cleavage of apoptosis-associated proteins. The antagonistic effect of H258 on H342-induced apoptosis indicates a pharmacokinetic basis for the two dyes' different biological effects. Differential global gene expression profiles induced by H258 and H342 are accompanied by unique gene expression signatures determined by DNA microarray and bioinformatics software, indicating a genetic basis for their different biological effects.A unique gene expression signature associated with H342-induced apoptosis provides a new avenue to predict and classify the therapeutic class of minor groove binders in the drug development process. Further analysis of H258-upregulated genes of transcription regulation may identify the genes that enhance transgene overexpression in gene therapy and promote recombinant protein products in biopharmaceutical companies.The microarray data reported in this article have been deposited in the Gene Expression Omnibus (GEO) database, www.ncbi.nlm.nih.gov/geo (accession no.GSE28616)