The stimulation protocol in poor responder IVF; a minimal or high-dose stimulation? - A meta-analysis.

Background To determine whether a minimal stimulation (MS) or high-dose stimulation (HDS) protocol is a better option for patients classified as poor ovarian responders (POR) in terms of reproductive and pregnancy outcomes. Materials and methods A database search for evaluation of the study outcome by using meta-analysis method was carried out. The primary outcome was the clinical pregnancy (CP) rate for each of two groups, namely, the MS and HDS groups. The secondary outcomes were the gonadotropin dose used, duration of stimulation, cancellation rate, number of oocytes retrieved, number of fertilized oocytes, number of embryos transferred and live birth rates. Results Across five databases, 4670 potential studies for further screening were selected. But ultimately only six studies, three RCTs and three retrospective or case control studies were selected that meet the Bologna criteria for POR. In all there were 624 cycles. Our meta-analysis indicated that the CP rates, cycle cancellation rates, durations of stimulation, numbers of oocytes fertilized and numbers of embryos transferred were not statistically significant. Clearly, the number of oocytes retrieved in the MS group was significantly lower than in the HDS group, while the HDS group consumed significantly higher doses of gonadotropins than the MS group. The live birth rates were significantly higher in the MS group than in the HDS group. Conclusion MS should be the first-line protocol for managing POR because the live birth rate is significantly higher, even with fewer oocytes retrieved.

Quantification of antigen by digital domain analysis of integrated nanogap biosensors.

Nanogap biosensor shows a distinct conduction change upon sandwich-type immobilization of gold nanoparticle probes onto the gap region in the presence of target biomolecules. Although this large conductance change could be advantageous in distinguishing signal on or off devices, since the extent of conductance change is quite irregular even at the same analyte concentrations, it fails to extract quantitative information from its level of conductance change. In other words, the conductance change of a single device does not reflect the concentration of the target molecule. In this study, we introduce an alternative approach of interpreting the concentration of target molecules using digital domain analysis of integrated nanogap devices, where the fraction of signal-on-devices, or on-device-percentage (ODP), was translated into the concentration of the target molecule. The ODP was found to be closely related to the number density of the immobilized probes and, therefore, to be an excellent measure of the analyte concentration, which was demonstrated in the immuno-selective detection and quantification of influenza A hemagglutinin and prostate specific antigen.

Fabrication of shape-controlled reduced graphene oxide nanorings by Au@Pt nanoring lithography.

We fabricated a variety of reduced graphene oxide (RGO) nanoring arrays using Au@Pt nanoplates as a pattern mask. RGO nanoflakes were assembled into a 2-dimensional assembly at the water-oil interface, and then various shapes of Au@Pt nanoplates were utilized as a pattern mask in order to convert the RGO into circular, triangular, and hexagonal RGO nanorings.

Gradient-Field-Plasma Modification of Imprinted Nanopatterns.

We report on a one-step progressive modification of imprinted nanopatterns for the induction of a structural and physicochemical gradient in a single chip with the use of gradually attenuated oxygen plasma. Imprinted line patterns could be easily tapered off to up to 60% of their original line width, which was found to be dependent upon the rate of plasma attenuation. Gradually modified nanopatterns are believed to have a continuous variation of physicochemical properties along the pattern gradient, which in this study was exemplified in contact angle variation, which was observed to be more than a factor of about 5 in 2 cm separation on a sample surface. It was also demonstrated for modified patterns used as replica molds for pattern reversal in consecutive processes. Furthermore, it was also proven that this gradual modification method is applicable to various imprint patterns of different structures and resist materials.

Nanogap-based electrical PNA chips for the detection of genetic polymorphism of cytochrome P450 2C19.

PNA chips for the detection of the genetic polymorphism of Cytochrome P450 2C19 (CYP2C19), a well-known enzyme related to the metabolism of therapeutic drugs, were electrically-interfaced with interdigitated nanogap electrodes (INEs). The average gap distance and effective length of the INEs were about approximately 70 nm and approximately 140/m, respectively. Those INEs having the aspect ratio of about 2000, were prepared by the combination of the photolithography (for the formation of initial electrodes) and the surface-catalyzed chemical deposition (for the gap narrowing), without the e-beam lithography. The PNA probes for the detection of CYP2C19 were immobilized in the gap region of INEs via Schiff base formation. The I-V characteristics clearly showed a sharp increase in the conductance between the nanogap electrodes upon the PNA-DNA hybridization, followed by the adsoprtion of functionalized Au nanoparticles. Four different target DNAs for the diagnosis of CYP2C19 polymorphism were successfully detected and discriminated with the INE-based PNA chips.