Microfluidic technology has the potential to revolutionise blood-clotting diagnostics by incorporating key physiological blood flow conditions like shear rate. In this paper we present a customised dynamic microfluidic system, which evaluates the blood clotting response to multiple conditions of shear rate on a single microchannel. The system can achieve high-throughput testing through use of an advanced fluid control system, which provides with rapid and precise regulation of the blood flow conditions in the platform. We present experimental results that demonstrate the potential of this platform to develop into a high-throughput, low-cost, blood-clotting diagnostics device.
Most Lab-on-a-Chip systems require a platform with external supply and control units to be operated. In this manuscript,
we report on the development of a modular optoelectronic microfluidic backplane, enabling the flexible interconnection,
supply, and control of microfluidic and optofluidic devices. The developed system was fabricated in polymers and
consists of backplane modules that may be individually connected with each other. Each module holds one dedicated
port on top for a device to be operated. In particular, we introduce an optical backplane module based on a novel optomechanical
light switch to guide light to the device of choice within the system. This modular approach allows
assembling an arbitrary number of different devices in three dimensions. In conclusion, the backplane provides a
configurable platform for multiple optofluidic applications.
This paper describes the development of methods for the determination of the characteristics and the behavior of living
neural cells. A technology which is used is the deep ultraviolet (DUV) modification of methylmethacrylate polymers
which leads to a new surface chemistry affecting the selective absorption of proteins and the adhesion of living cells in
vitro. The bi-functionality of the modified polymer chips supporting waveguides and cell anchorage capabilities at the
same time provides the opportunity to monitor protein adsorption, cell attachment and spreading processes by
evanescent-field techniques. This allows the defined spatial control of a cell/surface interaction and leads to a
combination of desired biological and optical properties of the polymer. Among them are the high sensitivity of cultured
mammalian cells to, for example, environmental changes and special features of integrated optical waveguides like their
online compatibility, minuteness and robustness. The scientific fields, biology and optics, meet at the polymer surface
becoming a cell culture substrate together with an optical waveguide by the application of special patterning and
fabrication technologies. In addition to the already mentioned fabrication and immobilization technology, the technique
proposed also offers the possibility of being able to couple to microstamping processes and to also incorporate electrical
measurements on individual cells. Thus, by extending this method and coupling it to the DUV technique described above
the possibility is given of being able to simultaneously optically and electrically interrogate individual cellular processes
with spatial resolution.
Deep UV-induced modification of the refractive index of polymers is a useful technique for low cost realization of
integrated optical circuits for telecommunication und sensor applications. The combination with replication techniques
like injection molding and hot embossing give the capability of a monolithic integration of these waveguide structures in
optical or fluidic microsystems. In addition the hybrid integration of these integrated optofluidic microsystems with
organic or inorganic photodiodes will open up the possibility to development novel, cheap, disposable integrated optical
sensors for environmental, chemical and biological monitoring.
The use of organic optoelectronic devices such as organic light-emitting diodes and organic photodiodes in micro-optical systems is discussed. Potential applications like optical interconnects and optical sensor systems are examined. Device characteristics including emission spectra, I-V-curves and the dynamic behaviour are analysed. In the combination with a polymeric optical fibre (POF) a transmission line comprising a organic light emitting diodes and organic photodiodes is demonstrated. An important step towards integration is realized by coupling the amplified spontaneous emission of an organic semiconductor material into a single-mode polymethylmethacrylate (PMMA) waveguide.
The use of conventional fabrication techniques for the fabrication of polymer based photonic integrated waveguide circuits is a necessary step to reduce costs. The replication of rib waveguides is presented using nickel shims. Results of replicated waveguides and 1 x 2 multimode interference (MMI) couplers are shown.
We investigate the deep-UV-induced refractive index modification of alicyclic methacrylate copolymers for realizing integrated optical circuits for the development of cheap, disposable integrated optical sensors for chemical and biological monitoring. These novel copolymers obtain higher glass transition temperature (Tg), refractive index and lower water absorption than conventional poly(methylmethacrylate) (PMMA). At the same time, the adhesion of living mammalian cells on the UV exposed polymer surface was investigated for the application for biosensor.
Polymer optical waveguide devices will play a key role in several rapidly developing areas such as optical networks, biophotonic and fluidic applications. We have developed a technology which enables the increase of the refractive index of methylmethacrylate based polymers by deep ultra violet (DUV) radiation. The modification of the dielectric properties of polymers by DUV is a useful technique for the realization of photonic integrated optical circuits. The
technique presented here has several advantages with respect to common methods because only a single polymer layer is used, which serves as the substrate and waveguide as well and no further etching or development step is required. This method can not only be applied to planar polymer substrates but also to preembossed substrates. This enables the fabrication of ridge waveguide based devices by hot embossing. Nickel stampers with feature heights of about 15-20 μm and aspect ratios usually between 2:1 and 3:1 can be utilized for replication without major effort. Nickel stampers are not only used to replicate optical waveguides, but are also used to realize fluidic channels in the range of several microns. UV modification of methylmethacrylate polymers additionally leads to a new surface chemistry affecting the selective absorption of proteins and the adhesion of living cells in vitro. The bi-functionality of the modified polymer chips supporting waveguides and cell anchorage capabilities at the same time provides the opportunity to monitor protein adsorption, cell attachment and spreading processes by evanescent-field techniques.
A process of UV-induced fabrication of single mode waveguides in a polymer microoptical bench has been realized that offers the unique feature of an inexpensive microstructure replication process for mass fabrication. Instead of using common mask techniques for the realization of the stripe waveguides, a "Self-masking" technique of the polymer by embossing a microoptical bench and a following UV-flood-exposure is used. The mould insert, which is necessary for the replication process was made by the LIGA-technique. The fabrication of the micooptical bench and the waveguides in the same process step assures very good alignment accuracy and guarantees a low cost passive fiber-chip coupling and assembly.
The photoinduced chemical reactions of different homo- and copolymers of methylmethacrylate under different environmental condition have been investigated. It was shown that depending on the environmental conditions during photoinduced waveguide generation, the physical and chemical properties of the waveguides can be adjusted in a wide range. The process allows the realization of devices for application in telecommunication and sensor technology.
The expansion of high capacity optical transmission techniques into price-sensitive areas such as datacom and access networks requires a major reduction in the cost of optical components. Polymer waveguides are attractive because they are very simple to process and are promising for low-cost devices. Deep UV-induced modification of the dielectric properties of polymers is a useful technique for low cost realization of integrated optical circuits for telecommunication und sensor applications. The technique presented here has several advantages with respect to common methods because only a single polymer layer is used, which serves as the substrate and waveguide as well and no further etching or development step is required. The integration of the waveguide circuits in a polymer microoptical bench offers the possibility of combining the devices with semiconductor based optical circuits and also achieve easy fiber-chip coupling. In this work, preliminary results of Y-junctions, directional couplers, multimode interference (MMI) couplers will be given.
Compact integrated microring resonators are promising candidates for various applications in optical signal processing and communication such as optical filters, wavelength (de)multiplexers, single mode sources, dispersion compensators and wavelength converters. Active GaInAsP/InP material is particularly suited for the fabrication of "lossless" filter devices as well as novel laser components with outstanding performance. Design, technology as well as transmission / emission mode characteristics for typical applications are sketched and summarized.
Miniaturization of waveguide circuits is inherently connected with the implementation of highly confined waveguides as one prerequisite for the building of sharp bends and optical microring circuits. Integrated optical ring resonators are promising candidates for compact optical filters and wavelength (de)multiplexers. Their realization in active semiconductor material opens the potential to verify "lossless" filter devices as well as novel laser components with outstanding performance. Since ring resonators do not require facets or gratings for optical feedback they are particularly suited for monolithic integration. Design and technology for device fabrication are summarized. Recent results on transmission and emission mode characteristics of fabricated passive ring resonators as well as gain-included "all-active" resonators in the transmission and emission mode are presented.