[Clinical significance of serum intestinal fatty acid-binding protein in full-term infants with necrotizing enterocolitis].

OBJECTIVE: To evaluate the clinical value of intestinal fatty acid-binding protein (I-FABP) in full-term newborn infants with necrotizing enterocolitis (NEC). METHODS: Forty-one full-term infants with a confirmed diagnosis of NEC from February 2012 to January 2014 were recruited as case group (stage I: 24 cases; stage II-III: 17 cases). Sixty-two children diagnosed with non-digestive diseases in the same period were recruited as the control group. Serum levels of I-FABP and C-reactive protein (CRP) were determined by enzyme-linked immunosorbent assay. The diagnostic value of I-FABP for NEC was assessed using the receiver operating characteristic (ROC) curve. RESULTS: Stage I and stage II-III cases in the case group had significantly higher serum I-FABP levels than the control group (P<0.05), and stage II-III cases had significantly higher serum I-FABP levels than stage I cases (P<0.05). The area under the ROC curve for serum I-FABP was 0.85 (95% CI: 0.78-0.92), with the optimal cut-off point of 2.25 ng/mL. Under this cut-off point, the sensitivity and specificity were 80.49% and 70.19%, respectively. There was no significant difference in serum CRP level between the case and control groups (P>0.05). CONCLUSIONS: In newborn infants with NEC, serum I-FABP level increases significantly in stage I , and it is correlated with the disease severity. Therefore, serum I-FABP can be used as a biomarker for the diagnosis of NEC.

A room temperature surface acoustic wave hydrogen sensor with Pt coated ZnO nanorods.

A surface acoustic wave (SAW) sensor with Pt coated ZnO nanorods as the selective layer has been investigated for hydrogen detection. The SAW sensor was fabricated based on a 128 degrees YX-LiNbO(3) substrate with a operating frequency of 145 MHz. A dual delay line configuration was adopted to eliminate external environmental fluctuations. The Pt coated ZnO nanorods were chosen as a selective layer due to their high surface-to-volume ratio, large penetration depth, and fast charge diffusion rate. The ZnO nanorods were synthesized by an aqueous solution method and coated with the noble metal Pt as a catalyst. Finally, the SAW sensor responses to humidity and hydrogen were tested. Results show that the sensor is not sensitive to humidity; moreover, the frequency shift for a hydrogen concentration variation of 6000 ppm is 26 kHz while operating at room temperature. It can be concluded that the Pt coated ZnO nanorod based SAW hydrogen sensor exhibits fast response, good sensitivity and short-term repeatability. It is worth noting that not only is the sensor sensitive enough to operate at room temperature, but also it can avoid the influence of humidity.

CE chips fabricated by injection molding and polyethylene/thermoplastic elastomer film packaging methods.

This study presents a new packaging method using a polyethylene/thermoplastic elastomer (PE/TPE) film to seal an injection-molded CE chip made of either poly(methyl methacrylate) (PMMA) or polycarbonate (PC) materials. The packaging is performed at atmospheric pressure and at room temperature, which is a fast, easy, and reliable bonding method to form a sealed CE chip for chemical analysis and biomedical applications. The fabrication of PMMA and PC microfluidic channels is accomplished by using an injection-molding process, which could be mass-produced for commercial applications. In addition to microfluidic CE channels, 3-D reservoirs for storing biosamples, and CE buffers are also formed during this injection-molding process. With this approach, a commercial CE chip can be of low cost and disposable. Finally, the functionality of the mass-produced CE chip is demonstrated through its successful separation of phiX174 DNA/HaeIII markers. Experimental data show that the S/N for the CE chips using the PE/TPE film has a value of 5.34, when utilizing DNA markers with a concentration of 2 ng/microL and a CE buffer of 2% hydroxypropyl-methylcellulose (HPMC) in Tris-borate-EDTA (TBE) with 1% YO-PRO-1 fluorescent dye. Thus, the detection limit of the developed chips is improved. Lastly, the developed CE chips are used for the separation and detection of PCR products. A mixture of an amplified antibiotic gene for Streptococcus pneumoniae and phiX174 DNA/HaeIII markers was successfully separated and detected by using the proposed CE chips. Experimental data show that these DNA samples were separated within 2 min. The study proposed a promising method for the development of mass-produced CE chips.

An integrated microfluidic chip for DNA/RNA amplification, electrophoresis separation and on-line optical detection.

This study presents an integrated microfluidic chip capable of performing DNA/RNA (deoxyribonucleic acid/ribonucleic acid) amplification, electrokinetic sample injection and separation, and on-line optical detection of nucleic acid products in an automatic mode. In the proposed device, DNA/RNA samples are first replicated using a micromachine-based PCR module or reverse transcription PCR (RT-PCR) module and then transported by a pneumatic micropump to a sample reservoir. The samples are subsequently driven electrokinetically into a microchannel, where they are separated electrophoretically and then detected optically by a buried optical fiber. The various modules of the integrated microfluidic chip are fabricated from cheap bio-compatible materials, such as PDMS, polymethylmethacrylate, and soda-lime glass. The functionality of the proposed device is demonstrated through its successful application to the DNA-based bacterial detection of Streptococcus pneumoniae and the RNA-based detection of Dengue-2 virus. It is shown that the low thermal inertia of the PCR/RT-PCR modules reduces the sample and reagent consumption and shortens the reaction time. With less human intervention, the subsequent DNA separation and detection could be performed in an automatic mode. The integrated microfluidic device proposed in this study represents a crucial contribution to the fields of molecular biology, genetic analysis, infectious disease detection, and other biomedical applications.

Integrated polymerase chain reaction chips utilizing digital microfluidics.

This study reports an integrated microfluidic chip for polymerase chain reaction (PCR) applications utilizing digital microfluidic chip (DMC) technology. Several crucial procedures including sample transportation, mixing, and DNA amplification were performed on the integrated chip using electro-wetting-on-dielectric (EWOD) effect. An innovative concept of hydrophobic/hydrophilic structure has been successfully demonstrated to integrate the DMC chip with the on-chip PCR device. Sample droplets were generated, transported and mixed by the EWOD-actuation. Then the mixture droplets were transported to a PCR chamber by utilizing the hydrophilic/hydrophobic interface to generate required surface tension gradient. A micro temperature sensor and two micro heaters inside the PCR chamber along with a controller were used to form a micro temperature control module, which could perform precise PCR thermal cycling for DNA amplification. In order to demonstrate the performance of the integrated DMC/PCR chips, a detection gene for Dengue II virus was successfully amplified and detected. The new integrated DMC/PCR chips only required an operation voltage of 12V(RMS) at a frequency of 3 KHz for digital microfluidic actuation and 9V(DC) for thermal cycling. When compared to its large-scale counterparts for DNA amplification, the developed system consumed less sample and reagent and could reduce the detection time. The developed chips successfully demonstrated the feasibility of Lab-On-a-Chip (LOC) by utilizing EWOD-based digital microfluidics.

Micromachined polymerase chain reaction system for multiple DNA amplification of upper respiratory tract infectious diseases.

This paper presents a micro polymerase chain reaction (PCR) chip for the DNA-based diagnosis of microorganism genes and the detection of their corresponding antibiotic-resistant genes. The micro PCR chip comprises cheap biocompatible soda-lime glass substrates with integrated thin-film platinum resistors as heating/sensing elements, and is fabricated using micro-electro-mechanical-system (MEMS) techniques in a reliable batch-fabrication process. The heating and temperature sensing elements are made of the same material and are located inside the reaction chamber in order to ensure a uniform temperature distribution. This study performs the detection of several genes associated with upper respiratory tract infection microorganisms, i.e. Streptococcus pneumoniae, Haemopilus influenze, Staphylococcu aureus, Streptococcus pyogenes, and Neisseria meningitides, together with their corresponding antibiotic-resistant genes. The lower thermal inertia of the proposed micro PCR chip relative to conventional bench-top PCR systems enables a more rapid detection operation with reduced sample and reagent consumption. The experimental data reveal that the high heating and cooling rates of the system (20 and 10 degrees C/s, respectively) permit successful DNA amplification within 15 min. The micro PCR chip is also capable of performing multiple DNA amplification, i.e. the simultaneous duplication of multiple genes under different conditions in separate reaction wells. Compared with the large-scale PCR system, it is greatly advantageous for fast diagnosis of multiple infectious diseases. Multiplex PCR amplification of two DNA segments in the same well is also feasible using the proposed micro device. The developed micro PCR chip provides a crucial tool for genetic analysis, molecular biology, infectious disease detection, and many other biomedical applications.