Molecular recognition with nanostructures fabricated by photopolymerization within metallic subwavelength apertures

The first demonstration of fabrication of submicron lateral resolution molecularly imprinted polymer (MIP) patterns by photoinduced local polymerization within metal subwavelength apertures is reported. The size of the photopolymerized MIP features is finely tuned by the dose of 532 nm radiation. Rhodamine 123 (R123) has been selected as a fluorescent model template to prove the recognition capability of the MIP nanostructures, which has been evaluated by fluorescence lifetime imaging microscopy (FLIM) with single photon timing measurements. The binding selectivity provided by the imprinting effect has been confirmed in the presence of compounds structurally related to R123. These results pave the way to the development of nanomaterial architectures with biomimetic artificial recognition properties for environmental, clinical and food testing.

Bio-Photonic Sensing Cells over transparent substrates for anti-gestrinone antibodies biosensing

In a previous work we introduced the term Bio-Photonic Sensing Cells (BICELLs), referred to periodic networks of nano-pillar suitable for biosensing when are vertically interrogated. In this article, we demonstrate the biosensing capabilities of a type of micrometric size BICELLs made of SU-8 nano-pillars fabricated over transparent substrates. We verify the biochips functionality comparing the theoretical simulations with the experimental results when are optically interrogated in transmission. We also demonstrate a sensitivity enhancement by reducing the pitch among nano-pillars from 800 to 700 nm. Thus, the Limit of Detection achievable in these types of BICELLs is in the order of 64 pg/mL for 700 nm in pitch among nano-pillars in comparison with 292 pg/mL for 800 nm in pitch when are interrogated by Fourier Transform Visible and Infrared Spectrometry. The experiments exhibited a good reproducibility with a relative standard deviation of 0.29% measured within 8 days for a specific concentration. Finally, BICELLs functionality was tested in real conditions with unpurified rabbit serum for detecting anti-gestrinone antibodies, demonstrating the high performance of this type of BICELLs to detect specific antibodies having immobilized the suitable bioreceptors onto the sensing surface.

Molecularly imprinted polymer diffraction grating as label-free optical bio(mimetic)sensor

Micropatterned molecularly imprinted polymer (MIP) transmissive 2D diffraction gratings (DGs) are fabricated and evaluated as label-free antibiotic bio(mimetic)sensors. Polymeric gratings are prepared by using microtransfer molding based on SiO(2)/Si molds. The morphology of the MIP gratings is studied by optical and atomic force microscopes. MIP 2D-DGs exhibit 2D optical diffraction patterns, and measurement of changes in diffraction efficiency is used as sensor response. The refractive index of the micropatterned MIP material was estimated, via solvent index matching experiments, to be 1.486. Immersion of a MIP 2D-DG in different solutions of target-antibiotic enrofloxacin leads to significant variations in diffraction efficiency, demonstrating target-molecule detection. On the other hand, no significant response is observed for both control experiments: MIP grating exposed to a non-retained analyte and an equivalent non-imprinted polymer grating exposed to the target analyte, showing highly specific antibiotic label-free optical recognition.

A packaged optical slot-waveguide ring resonator sensor array for multiplex label-free assays in labs-on-chips

We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.

Microfluidic and transducer technologies for lab on a chip applications

Point-of-care diagnostic devices typically require six distinct qualities: they must deliver at least the same sensitivity and selectivity, and for a cost per assay no greater than that of today's central lab technologies, deliver results in a short period of time (〈15 min at GP; 〈2h in hospital), be portable or at least small in scale, and require no or extremely little sample preparation. State-of-the-art devices deliver information of several markers in the same measurement.

Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform

We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

Use of olanzapine in non-psychotic psychiatric disorders

The history of antipsychotic medications begins in the 1950s with chlorpromazine, developed originally as an antihistamine but found to be an aid in the reduction of symptoms of delusions and hallucinations. This phenothiazine derivative was followed by numerous others in the same class (e.g., thioridazine) and then by antipsychotics in other classes (e.g., the popular haloperidol of the butyrophenone class). This group of medications is associated with a number of unpleasant side effects and complications. These included extrapyramidal symptoms (EPS), orthostatic hypotension, hyperprolactinemia and last, but certainly not least, tardive dyskinesia (TD). As a consequence, other alternative antipsychotics were developed in which D(2) blockade effect generally associated with EPS and TD was offset by 5-HT(2) antagonism. The first of this class was clozapine; however, it is associated with agranulocytopenia of sudden onset as well as seizure induction. However, olanzapine, a close structural relative, was soon synthesised for treatment of psychosis and particularly schizophrenia (Zyprexatrade mark, Eli Lilly). It was released in the US in November 1996 with FDA approval for that indication. However, antipsychotics have always been used for other psychiatric disorders, aside from schizophrenia. This includes, in particular, mania, where chlorpromazine use predated lithium as an effective treatment. Other uses for antipsychotics have included other mood disorders, dementia, childhood disorders and personality problems. Here, information on the application of olanzapine to non-schizophrenic disorders is reviewed. Despite the fact that the research post-dates FDA approval in 1996, there was already sufficient evidence for olanzapine's effectiveness in acute mania to obtain approval from the US FDA in March 2000. Other research supports its use as adjunctive therapy in depressive disorders. Phase IV studies and case reports have found limited support for olanzapine's use in a variety of other psychiatric disorders, behavioural disorders of dementia (including Alzheimer's disease), pervasive developmental disorder of childhood, obsessive-compulsive disorder and borderline personality disorder. In each of these latter diagnoses, double-blind studies are either underway or are planned to establish efficacy.

[Mercury in the hair of pregnant and lactating Chilean mothers]

Mercury-containing industrial waste has been released into the coastal waters of the Eighth Region of Chile for around two decades. This study, carried out from 1991 to 1993, sought to measure mercury concentrations in the hair of pregnant and lactating women from villages near the coast and in the interior of the region in order to examine the relationship between the concentration of mercury and seafood consumption. The survey questionnaire used in 1991 to determine seafood consumption did not ask about the frequency of consumption of fish, shellfish, and algae but only whether the women who were pregnant or breast-feeding consumed a minimum of one fish-based meal per week. The questionnaire used in 1992 and 1993 asked about the daily and weekly consumption of seafood in general (fish, shellfish, and algae). Spectrophotometry was used to determine the total mercury concentration in samples of 100 mg of hair from 153 pregnant and lactating women in 11 fishing villages of the Eighth Region where seafood is regularly consumed. None of the women had occupational exposure to mercury. Total mercury concentration was also determined in hair samples from a control group composed of 26 pregnant and lactating women from Pinto and El Carmen, villages in the interior of the same region where seafood was rarely eaten. The arithmetic mean of the total mercury concentration in hair was 1.81 mg/kg of body weight for the study group (standard deviation [SD] 1.52) and 0.42 mg/kg for the control group (SD 0.15)--a statistically significant difference (P < 0.01). Pairwise comparisons also revealed statistically significant differences (P < 0.05) between the mean for the interior group and the means for the women in the nine villages closest to the sources of the pollution, but not between the mean for the interior group and those for women in the two villages at the extreme north and south of the study zone, who lived farthest from the contaminated waters. The total mercury concentration in hair was significantly higher in women who indicated that they ate fish seven or more times per week; in those who said they ate fish, shellfish, or algae five or more times per week; and in those who had lived 20 or more years in their village. No statistically significant differences were found when the results were analyzed by age.