The Atomic Force Microscope (AFM) has been used for the characterization of polydimethylsiloxane (PDMS) surfaces
with embedded, randomly dispersed micron-sized glass beads as a model system for a nano-topographical composite
material with adjacent hydrophobic/hydrophilic areas. The use of lateral force microscopy (LFM) for the differentiation
of regions within a composite material allowed for a mapping of the position of the hydrophilic glass beads, the
determination of the height of the protruding beads and the surface area of the glass. Material properties of the PDMS
were obtained from AFM contact-mode scans, contact angle measurements and from Fourier transform infrared
spectroscopy for both, unexposed surfaces and surfaces exposed for 3 hours with a 185 nm deep UV light source. The
UV exposure was found to have an effect on the lateral force signal via a change in the stiffness of the PDMS but the
resulting lower contrast was still sufficient for the discrimination of the different regions.
Fungal growth is concentrated in elongated tips, called hyphae, which have the tendency to maintain their direction of growth. Hyphal tips exhibit a number of tropisms in response to various factors e.g. nutrients, light, physical contact.Irradiation in the area of hyphal tips with a 1064 nm laser affected shown a sensing mechanism within the fungal tip. The result of this was a change of growth direction caused by Spitzenkoerper's tendency to move away from the trap. The manipulation of the growth orientation of fungi in microstructures using focused laser beam has the potential to help the understanding of space search algorithms used by microorganisms.
The identification and differentiation of colours is a relatively problematic task for colour-impaired and partially vision-impaired persons and an impossible one for completely blind. In various contexts, this leads to a loss of independence or an increased risk of harm. The identification of colour using optoelectronic devices, on the other hand, can be done precisely and inexpensively. Additionally, breakthroughs in miniaturising and integrating colour sensors into biological systems may lead to significant advances in electronic implants for alleviating blindness. Here we present a functional handheld device developed for the identification of colour, intended for use by the vision-impaired. We discuss the features and limitations of the device and describe in detail one target application - the identification of different banknote denominations by the blind.
The non-invasive or minimally invasive real-time spectral analysis of tissue and biological fluids in vivo would be of great assistance for diagnosis and monitoring of a wide range of diseases. We propose here a novel microdevice capable of determining the reflectance spectrum of a sample using a set of micrometer-sized light emitting diodes and a patch of photosensitive material. The purported device would be wireless and remote-powered via RF magnetic fields and due to its dimensions would be suitable as a long-term implant, for example for monitoring glucose levels in diabetics. We present a design for this device, discuss its limitations and suggest some applications, including its use for in vivo biochemical assays.