Poly(dimethylsiloxane) also known as PDMS is used in a wide range of biomedical applications. These range from implants through catheters to soft contact lenses. Therefore, it is understandable that PDMS has been extensively tested for these purposes. In past years, the microfluidics has moved from predominantly silicon and glass structures towards polymers due to their ease of manufacturing and moderate cost. PDMS has gained a lot of attention in various analytical applications. However, the testing of its suitability for such applications has not been as thorough as in the biomedical applications, perhaps relying on the experiments from that field. Microfluidic PDMS structures are more and more popular in various analytical devices. Such devices consume less reagents and can work with lower sample volumes. On the other hand, the surface-to-sample-volume ratio becomes larger. That increases the influence of material properties on the actual measurement. Some of the challenges include adsorption, diffusion, surface roughness, permeability and elasticity of PDMS, which are discussed in this paper.

Coupling of surface plasmon resonance (SPR) detection to asymmetric flow field-flow fractionation (AF4) offers the possibility to study active fractions of bio-separations on real samples, such as serum and saliva, including the assessment of activity of possibly aggregated species. The coupling of SPR with AF4 requires the possibility to select fractions from a fractogram and redirect them to the SPR. The combination of SPR with chromatography-like methods also requires a mechanism for regeneration of the receptor immobilised onto the SPR sensor surface. In recent work, the combination of size exclusion chromatography (SEC) with SPR was pioneered as a successful methodology for identification, characterisation and quantification of active biocomponents in biological samples. In this study, the approach using AF4 is evaluated for the antibody trastuzumab in buffer and serum. The particular object of this study was to test the feasibility of using AF4 in combination with SPR to detect and quantify proteins and aggregates in complex samples such as blood serum. Also, in the investigation, three different immobilisation methods for the receptor HER-2 were compared, which involved (1) direct binding via EDC/NHS, the standard approach; (2) immobilisation via NTA-Ni-Histag complexation; and (3) biotin/avidin-linked chemistry using a regenerable form of avidin. The highest specific activity was obtained for the biotin-avidin method, while the lowest specific activity was observed for the NTA-Ni-Histag linkage. The data show that AF4 can separate trastuzumab monomers and aggregates in blood serum and that SPR has the ability to selectively monitor the elution. This is an encouraging result for automated analysis of complex biological samples using AF4-SPR.

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This paper is divided into two parts. The first part describes the current status and the general challenges of developing automatic microrobotics systems for microinjection of adherent mammalian cells. The discussion covers applications and the review and challenges of the components of a capillary pressure microinjection system: a micromanipulator, a microinjector, a microcapillary, a vision system and an environment control system. The second part of the paper describes the research performed on the automatic capillary pressure microinjection at Tampere University of Technology. The advanced microinjection system includes two micromanipulators, a microinjector, a vision system and a control system. The control system comprises motion control schemes for the micromanipulators to accurately position a microcapillary, to precisely penetrate a cell membrane and to deliver information on the injection to the operator. A novel injection guidance system, being part of the control system, comprises an impedance measurement device and a user interface which provide information on the detection of the capillary-membrane contact, capillary clogging and capillary breakage. Results show a remarkable increase of the injection success from 40 to 65% when the injection guidance system is used.