Doxycycline inhibits electric field-induced migration of non-small cell lung cancer (NSCLC) cells.

Adenocarcinoma, large cell carcinoma and squamous cell carcinoma are the most commonly diagnosed subtypes of non-small cell lung cancers (NSCLC). Numerous lung cancer cell types have exhibited electrotaxis under direct current electric fields (dcEF). Physiological electric fields (EF) play key roles in cancer cell migration. In this study, we investigated electrotaxis of NSCLC cells, including human large cell lung carcinoma NCI-H460 and human lung squamous cell carcinoma NCI-H520 cells. Non-cancerous MRC-5 lung fibroblasts were included as a control. After dcEF stimulation, NCI-H460 and NCI-H520 cells, which both exhibit epithelial-like morphology, migrated towards the cathode, while MRC-5 cells, which have fibroblast-like morphology, migrated towards the anode. The effect of doxycycline, a common antibiotic, on electrotaxis of MRC-5, NCI-H460 and NCI-H520 cells was examined. Doxycycline enhanced the tested cells' motility but inhibited electrotaxis in the NSCLC cells without inhibiting non-cancerous MRC-5 cells. Based on our finding, further in-vivo studies could be devised to investigate the metastasis inhibition effect of doxycycline in an organism level.

Multiplex detection of urinary miRNA biomarkers by transmission surface plasmon resonance.

The clinical assessment of short-stranded nucleic acid biomarkers such as miRNAs could potentially provide useful information for monitoring disease progression, prompting definitive treatment decisions. In the past decade, advancements in biosensing technology have led to a shift towards rapid, real-time and label-free detection systems; as such, surface plasmon resonance (SPR) biosensor-based technology has become of high interest. Here, we developed an automated multiplex transmissive surface plasmon resonance (t-SPR) platform with the use of a capped gold nanoslit integrated microfluidic surface plasmon resonance (SPR) biosensor. The automated platform was custom designed to allow the analysis of spectral measurements using wavelength shift (dλ), intensity (dI) and novel area change (dA) for surface binding reactions. A simple and compact nanostructure based biosensor was fabricated with multiplex real-time detection capabilities. The sensitivity and specificity of the microfluidic device was demonstrated through the use of functionalised AuNPs for target molecule isolation and signal enhancement in combination with probes on the CG nanoslit surface. Our work allows for the multiplex detection of miRNA at femtomolar concentrations in complex media such as urine.

Electrokinetic acceleration of DNA hybridization in microsystems.

In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems.

Urinary micro-RNA biomarker detection using capped gold nanoslit SPR in a microfluidic chip.

Successful diagnosis and treatment of many diseases depends on the availability of sensitive, reliable and low cost tools for the detection of the biomarkers associated with the diseases. Simple methods that use non-invasive biological samples are especially suitable for the deployment in the clinical environment. In this paper we demonstrate the application of a method that employs a capped gold nanoslit surface plasmon resonance (SPR) sensor and a microfluidic chip for the detection of a urinary nucleic acid biomarker in clinical samples. This method detects low concentrations of the biomarker in a relatively large volume (∼1 mL) of the sample. The method utilizes magnetic nanoparticles (MNPs) for the isolation of target molecules and signal enhancement in conjunction with surface plasmon resonance (SPR) on capped gold nanoslits. The ability of the method to detect urinary miRNA-16-5p in AKI patients was tested and the result was compared with the data obtained with the polymerase chain reaction (PCR). miRNA-16-5p has been found to be a specific and noninvasive biomarker for acute kidney injury (AKI). Our method allows the detection of the biomarker in the urine of AKI patients without amplification and labeling of the target molecules.

Label-free detection of rare cell in human blood using gold nano slit surface plasmon resonance.

Label-free detection of rare cells in biological samples is an important and highly demanded task for clinical applications and various fields of research, such as detection of circulating tumor cells for cancer therapy and stem cells studies. Surface Plasmon Resonance (SPR) as a label-free method is a promising technology for detection of rare cells for diagnosis or research applications. Short detection depth of SPR (400 nm) provides a sensitive method with minimum interference of non-targets in the biological samples. In this work, we developed a novel microfluidic chip integrated with gold nanoslit SPR platform for highly efficient immunomagnetic capturing and detection of rare cells in human blood. Our method offers simple yet efficient detection of target cells with high purity. The approach for detection consists of two steps. Target cells are firs captured on functionalized magnetic nanoparticles (MNPs) with specific antibody I. The suspension containing the captured cells (MNPs-cells) is then introduced into a microfluidic chip integrated with a gold nanoslit film. MNPs-cells bind with the second specific antibody immobilized on the surface of the gold nanoslit and are therefore captured on the sensor active area. The cell binding on the gold nanoslit was monitored by the wavelength shift of the SPR spectrum generated by the gold nanoslits.

Magnetic nanoparticle-enhanced SPR on gold nanoslits for ultra-sensitive, label-free detection of nucleic acid biomarkers.

We have demonstrated a detection method for the ultra-sensitive detection of an mRNA biomarker. The method utilizes functionalized magnetic nanoparticles (MNPs) for signal enhancement in conjunction with surface plasmon resonance (SPR) on gold nanoslits. The approach for detection includes double hybridization at two different specific locations in two steps. First, the biomarker target molecule is captured with MNPs, and second, MNPs carrying the target molecule are introduced to the SPR chip to hybridize with probes immobilized on the gold nanoslits. In this work, MNPs were applied for a dual purpose: to isolate the target molecule from the sample matrix to prevent non-specific binding and to enhance the SPR response. Gold nanoslits that provide SPR sensing were fabricated by nanoimprinting lithography on polycarbonate (PC) film. The film was integrated with a microliter volume microfluidic chip to form the SPR detection chip. This detection method was used to detect mRNA heterogeneous nuclear ribonucleoproteins (hnRNP B1) in two cancer cell lines, CL1-0 and CL1-5. hnRNP B1 is an mRNA biomarker that is overexpressed in lung cancer tissue in the early stage of cancer and can be found in the serum and plasma of lung cancer patients. A synthetic target molecule and extracted total RNA from the cell lines were used as samples. Without amplification and labeling of the target molecule, the SPR results demonstrate a specific and sensitive method for the detection of hnRNP B1 mRNA in extracted RNA from the two selected cell lines. The method is capable of measuring down to 30 fM of the target molecule in a 7 µl sample (corresponding to 1.26 × 10(5) molecules) without amplification and labeling of the target molecule.

Gene expression of human lung cancer cell line CL1-5 in response to a direct current electric field.

BACKGROUND: Electrotaxis is the movement of adherent living cells in response to a direct current (dc) electric field (EF) of physiological strength. Highly metastatic human lung cancer cells, CL1-5, exhibit directional migration and orientation under dcEFs. To understand the transcriptional response of CL1-5 cells to a dcEF, microarray analysis was performed in this study. METHODOLOGY/PRINCIPAL FINDINGS: A large electric-field chip (LEFC) was designed, fabricated, and used in this study. CL1-5 cells were treated with the EF strength of 0 mV/mm (the control group) and 300 mV/mm (the EF-treated group) for two hours. Signaling pathways involving the genes that expressed differently between the two groups were revealed. It was shown that the EF-regulated genes highly correlated to adherens junction, telomerase RNA component gene regulation, and tight junction. Some up-regulated genes such as ACVR1B and CTTN, and some down-regulated genes such as PTEN, are known to be positively and negatively correlated to cell migration, respectively. The protein-protein interactions of adherens junction-associated EF-regulated genes suggested that platelet-derived growth factor (PDGF) receptors and ephrin receptors may participate in sensing extracellular electrical stimuli. We further observed a high percentage of significantly regulated genes which encode cell membrane proteins, suggesting that dcEF may directly influence the activity of cell membrane proteins in signal transduction. CONCLUSIONS/SIGNIFICANCE: In this study, some of the EF-regulated genes have been reported to be essential whereas others are novel for electrotaxis. Our result confirms that the regulation of gene expression is involved in the mechanism of electrotactic response.

Design of a high-efficiency grating coupler based on a silicon nitride overlay for silicon-on-insulator waveguides.

A waveguide grating coupler based on a silicon nitride overlay at 1.55 µm for TE polarization is designed with no experimental demonstration. Its coupling efficiency for a fiber is 76%, the 1 dB bandwidth is 75 nm, and the coupling angle is 10°. The effects of different device parameters on the coupling performance for the grating coupler are discussed. The coupling efficiency of our grating coupler is almost equal, yet the 1 dB spectral bandwidth is around 25 nm broader, as compared with the grating coupler design based on a poly-silicon overlay. The coupling performance of our coupling device could still be further improved. The grating coupler presented in this paper is applicable to the optical coupling in nanophotonic integrated circuits.

Microfluidic ARray Synthesizer (MArS) for rapid preparation and hybridization of custom DNA microarray.

The purpose of this work is to demonstrate a simple method that integrates custom DNA array synthesis and hybridization in a microfluidic channel. Commercial DLP projectors and a classical oligonucleotide synthesizer were integrated with a microfluidic chamber and constitute a Microfluidic ARray Synthesizer (MArS). Utilizing the benefit of microfluidics, the MArS produces two custom oligonucleotide arrays with reagent consumption for one array. The quality of the two arrays was examined by hybridization and shown to be almost identical. Post-synthesis deprotection of the array and hybridization performed in the same microfluidic chamber reduced overall DNA assay time by two orders. In addition, mismatch discrimination was enhanced using the microfluidic chamber. In summary, a simple method to build a custom array synthesizer is demonstrated and its performance is examined.

[A survey of sanitary working status 20 days after the earthquake in Dujiangyan municipality].

OBJECTIVE: To investigate the sanitary working status in the districts for locating residents after earthquake in Dujiangyan municipality. METHODS: Some immediate measures were taken after the earthquake including water source surveillance, restoring immunization system and epidemic surveillance. A questionnaire survey was also conducted to collect information in 107 locating districts of 18 towns. RESULTS: Generally, the sanitary working status was good. Temporary sheds in most districts were Tents (75.70%, 81/107) and simple sheds (19.63%, 21/107), and 69.16% (74/107) districts could use water supply and 94.39% (101/107) arrange specialized persons to disinfect the environment and kill pests. The fly density was 2 per eye-view. The proportions for the correct responds to health knowledge, action adopted and attitude of residents were all above 90%. According to the epidemic surveillance system and mobile syndrome surveillance system in disaster area, there was no increasing trend for the incidences of contagious diseases. CONCLUSION: 20 days after earthquake, the whole situation of disease prevention in disaster area is stable.

Proteomic analysis of rice defense response induced by probenazole.

Here, we report the first proteomic analysis of rice defense response induced by probenazole (PBZ), an agricultural chemical that has been widely used to protect rice plants from rice blast and the bacterial blight pathogen. Two-dimensional gel electrophoresis (2-DE) was utilized to identify a total of 40 protein spots including 9 protein spots that are up-regulated by PBZ and 31 abundant protein spots. A total of 11 unique proteins from these 9 spots were identified by LC-MS/MS, and the majority of them were classified and/or possessed orthologs in defense-related functions. Five protein spots with only one protein species identified in each spot appear to be PBZ-regulated proteins. They are a putative glutathione S-transferase GSTU17, a putative phenylalanine ammonia-lyase (PAL, XP_466843), a putative caffeic acid 3-O-methyltransferase (COMT), a putative NADH-ubiquinone oxidoreductase, and a putative glucose-1-phosphate adenyltransferase. However, the other six protein species identified from the remaining four protein spots could not be conclusively described as PBZ-regulated proteins due to either the co-migration of two protein species in one spot or the presence of one protein species in two spots. Through real-time reverse transcription polymerase chain reaction (RT-PCR), it was determined that PAL (XP_466843) is likely regulated at the protein level, whereas GSTU17 and COMT were regulated at the mRNA level after PBZ application. Interestingly, the mRNA transcripts of two PAL paralogs were found to be up-regulated by PBZ. We propose that PAL, COMT, and GSTU17 are likely to confer PBZ-induced disease resistance via such functions as biosynthesis and transport of flavonoid-type phytoalexin and/or lignin biogenesis.

Humidity effect on the decay of second-order nonlinearity in thermally poled fused silica.

Type I (GE124) and Type II (KV) fused silica were thermally poled in a vacuum and in air under identical poling conditions. Second-order nonlinear (SON) strength and nonlinear depth were found all to be the same. Samples were then stored in high and low humidity to study their SON stability. The SON of poled GE124 was stable over time despite different poling atmospheres and humidity in storage. The SON of both the air-poled and vacuum-poled KV samples decayed over time in both low and high humidity, with the exception that the air-poled KV sample stored in low humidity remained stable. High humidity accelerated the decay process of the KV samples. A porous surface model was used to interpret the decay mechanism. The decay curves implied multiple carriers or a multiple-porosity model for the decay mechanism.

Quasi-phase-matched second-harmonic generation in Ge-ion implanted fused silica channel waveguide.

Channel waveguides were formed on fused silica substrate by Ge-ion implantation with lithographically defined channels. Thermal poling was performed to form second order optical nonlinearity (SON) in the waveguides. Periodical photo masks were designed and fabricated on a mask glass. Periodical erasure of the SON in the channel waveguides by 266 nm UV light with the photo mask on the fused silica substrate produced periodical SON distribution in the waveguides. First order quasi-phase-matching second-harmonic generation from 1064 nm to 532 nm was demonstrated in the channel waveguides.

Quasi-phase-matched second-harmonic generation in ultraviolet-assisted periodically poled planar fused silica.

First-order quasi-phase-matched second-harmonic generation of 1064 to 532 nm in a thermally poled planar fused-silica plate with periodic UV erasure of the second-order nonlinearity was successfully implemented. We obtained a 1:2.9 ratio of d31:d33 for UV-grade fused silica in support of the proposed mechanism for electric-field-induced second-order nonlinearity in this material.