Fibre coupled micro-light emitting diode array light source with integrated band-pass filter for fluorescence detection in miniaturised analytical systems

In this work, a new type of miniaturized fibre-coupled solid-state light source is demonstrated as an excitation source for fluorescence detection in capillary electrophoresis. It is based on a parabolically shaped micro- light emitting diode (µ-LED) array with a custom band-pass optical interference filter (IF) deposited at the back of the LED substrate. The GaN µ-LED array consisted of 270 individual µ-LED elements with peak emission at 470nm, each about 14µm in diameter and operated as a single unit. Light was extracted through the transparent substrate material, and coupled to an optical fibre (400µm in diameter, numerical aperture NA = 0.37), to form an integrated µ-LED-IF-OF light source component. This packaged µ-LED-IFOF light source emitted approximately 225µW of optical power at a bias current of 20mA. The bandpass IF filter was designed to reduce undesirable LED light emissions in the wavelength range above 490 nm . Devices with and without IF were compared in terms of optical power output, spectral characteristics as well as LOD values. While the IF consisted of only 7.5 pairs (15 layers) of SiO2/HfO2 layers it resulted in an improvement of the baseline noise as well as the detection limit measured using fluorescein as test analyte, both by approximately one order of magnitude, with a LOD of 1×10-8 mol/L obtained under optimised conditions. The µ-LED-IF-OF light source was then demonstrated for use in capillary electrophoresis with fluorimetric detection. Limits of detection obtained by this device were compared to those obtained with a commercial fibre coupled LED device

Molecularly imprinted polymers on the surface of magnetic nanoparticles for selective separation and detection of nucleobases

Nucleobases are the main building blocks in DNA and RNA playing very important roles in cell metabolism. Changes of bases in DNA sequence may affect function of products of gene expression - proteins, and this can lead to inherited diseases and most human cancer types. Pharmacological studies, clinical diagnosis and others areas need a quick, inexpensive and exact method for determination of nucleobases. In this work, we explore the possibility of improving detection of nucleobases by using capillary electrophoresis in combination with isolation by magnetic particles modified by molecularly imprinted polymer

Utilization of antibody-nanoparticle conjugates as a tool for immunochemistry with ICP-MS detection

Immunoanalytical techniques are key methods of application in clinical diagnostics, genomics, proteomics and other biochemical and molecular biology disciplines. Most often, they are based on the ability of labeled antibodies to bind specific antigens. It is possible to use a large variety of nanomaterials that are designed, synthesized and adapted to allow highly sensitive detection of advanced immunoassays. Detection can be a highly efficient analytical method of laser ablation followed by inductively coupled plasma mass spectrometry (LA-ICP-MS), which allows the detection of elemental tags suitably conjugated to antibodies. The aim of this work was to conjugate model anti-mouse antibody on a surface of 10nm and 60nm gold nanoparticles and choose the better one for conjugation experimentally by using dot-blot immunobinding assay followed by LA-ICP-MS. It has been experimentally proven that 10nm gold nanoparticles are more suitable for conjugation with antibodies because of lower non-specific sorption on a membrane

The assessment of the semicircular canals and cochlea of the human bony labyrinth using imaging techniques

The human bony labyrinth is an inner ear structure located inside the pyramid of the temporal bone that encloses the organs of sound perception and balance. As one of the most resistant skeletal elements in human body, the pyramid is frequently uncovered in a good state of preservation. Until recently, research of the human bony labyrinth had been restricted exclusively to irreversibly invasive techniques. Due to this invasiveness, literature on morphological variation has been scarce and many questions regarding population, age or sex-related differences are yet to be answered. The studied sample of pyramids originated from Dětkovice - Za zahradama Site (Czech Republic) dated to 1000’s and 1100’s A.D. All elements were examined using an X-ray Carestream Xtreme device and a cone-beam CT unit. In digital X-ray images, linear distance of the semicircular canals and cochlear diameter were measured in ImageJ program. CT images were first processed to generate 3D digital models, which were subsequently studied using a newly established PC-aided approach employing measuring functionalities available in GOM Inspect program. Altogether 39 variables were proposed in order to describe shape and size variation in the semicircular canals. Acquired measurements were confronted and tested against individual's demographic data determined based on corresponding skeletal elements and burial attributes. The results showed small to none sex-related and body side-specific differences. Still, statistically significant differences were shown between sub-adults and adults. They were particularly evident in size variables of the lumens of the lateral and posterior semicircular canal, where larger values for adults were provided. This indicates a widening of the canals during growth by the resorption in the vicinity of the canals. The acquired results contribute to our comprehension of the development of inner ear structures and demonstrate the potential of the employment of non-invasive approaches when examining human skeletal remains