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Herein, a finger-free wrist-worn pulse oximeter is presented. This device allows patients to measure blood oxygen level and pulse rate without hindering their normal finger movement. This wrist-worn pulse oximeter is built with a reflectance oximetry sensor, which consists of light emitting diodes and photodiode light detectors located side by side. This reflectance oximetry sensor is covered with an optical element with micro structured surface. This micro structured optical element is designed to modulate photon propagation beneath the skin tissue so that the photoplethysmogram signals of reflected lights or backscattered lights detected by the photodetector are therefore enhanced.

Creatinine has become an important clinical analyte that is used for the determination of renal and muscular dysfunction. It is essential to determine its concentration in the serum of patients suffering from renal insufficiency. Therefore, an amperometric creatinine biosensor fabricated from a covered platinum/silver electrode with a thin layer of an immobilized multienzyme membrane was studied. Poly(acrylic acid) was introduced onto an argon-plasma-treated porous polypropylene membrane surface by graft copolymerization. Subsequently, three different enzymes (sarcosine oxidase, creatinase, and creatininase) were immobilized onto this novel grafted membrane simultaneously via a carbodiimine agent to form a thin layer. The sensor performance was evaluated with a biochemistry analyzer. Moreover, attenuated total reflection/Fourier transform infrared, electron spectroscopy for chemical analysis, and scanning electron microscopy were used to confirm the progression of these reactions. The developed sensor showed a linear detection range of 3.2–320 μM for creatinine in a pH 7.4 buffered solution with 0.1M phosphate. The immobilized multienzyme membrane could be used for at least 3 weeks. The results obtained in our study will hopefully lead to the successful application of modified polypropylene for the development of a creatinine sensor. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3126–3134, 2004

A compact and position-addressable blue ray scanning microscope (BSM) based on a commercially available Blu-ray disk pickup head (PUH) is developed for cell imaging with high resolution and low cost. The BSM comprises two objective lenses with numerical apertures (NAs) of 0.85 and 0.6 for focusing blue and red laser beams, respectively, on the sample slide. The blue and red laser beams are co-located adjacent to each other and move synchronously. A specially designed sample slide is used with a sample area and an address-patterned area for sample holding and address recognition, respectively. The blue laser beam is focused on the sample area and is used for fluorescent excitation and image capturing, whereas the red laser beam is focused on the address-patterned area and is used for address recognition and dynamic focusing. The address-patterned area is divided into 310 sectors. The cell image of each sector of the sampling area has a corresponding address pattern. Fluorescence images of monkey-derived kidney epithelial cells and fibroblast cells in which the F-actin is stained with fluorophore phalloidin CF 405 are measured by the BSM, with results comparable to those measured by a Leica TCS CP2 confocal microscope. The cell image of an area of interest can be easily tracked based on the coded address, and a large-area sample image can be accurately reconstructed from the sector images.

The detection and concentration of cancer cells in peripheral blood is of great importance for cancer diagnosis and prognosis. Optically-induced dielectrophoresis (ODEP) can achieve high resolution and low optical intensities, and the electrodes pattern can be dynamically changed by varied light pattern. In this paper, a special lens is used to project the entire image to the ODEP chip to achieve 2.6 × 2 mm(2) manipulating area. By changing projected light pattern, it is demonstrated to separate 10, 20, and 40 µm PS (polystyrene) beads; HT-29, 20 µm PS beads. The MCF-7 cells concentrated experiments are also demo at 100 µm/sec velocity.

The optically-induced dielectrophoretic (ODEP) technology has many advantages such as low light energy (~ 102 W/cm2), virtual electrodes, large manipulating area and rapid screening of cells. In this paper, 20 μm polystyrene beads are manipulated by a light circle and concentrated by a variable radius circle. The 10 μm and 40 μm polystyrene beads are successfully separated by a 40 μm light line width with vibrating beveled microfluidic light channels.

The ODEP technology has many advantages such as low light energy (∼ 102 W/cm2), virtual electrodes, large manipulating area and rapid screening of cells. In this paper, the 10 µm and 20 µm polystyrene beads are successfully separated by a 40 µm light line width with variable radius circle. Human colon cancer cells (HT-29) concentration experiments are demonstrated and can achieve at the maximum speed about 100 µm/sec.

This paper presents a three-axis, low-g accelerometer IC with analog and digital outputs for applications in consumer and mobile markets. This accelerometer is consisted of a sensing element chip and a digital IC, and is packed in a 3mm x 5mm x 0.9mm LGA package. The sensing element integrates three spring-proof mass systems with self test electrodes on a single structure for sensing three-axis motion for operating range of ± 5 g. The programmable resolution for digital output which offers user to adjust the resolution for different applications; and, nominally, the maximum resolution is as high as 16 Bits. The overall noise floors of the x-, y-, and z-axis are 408µg/√Hz, 460µg/√Hz, 238µg/√Hz, respectively. From the characterization, this accelerometer IC demonstrates high cross-axis sensitivity immunity, high sensitivity, and good linearity for both in-plane and out-of-plane accelerometers that suggests this three-axis accelerometer to be potential for satisfying the needs of current applications to consumer and mobile market.

Detecting and concentrating cancer cells in peripheral blood is of great importance for cancer diagnosis and prognosis. Optically induced dielectrophoresis (ODEP) can achieve high resolution and low optical intensities, and the electrode pattern can be dynamically changed by varied light patterns. By changing the projected light pattern, it is demonstrated to separate high-purity gastric cancer cell lines. Traditionally, the purity of cancer cell isolation by negative selection is 0.9% to 10%; by positive selection it is 50% to 62%. An ODEP technology is proposed to enhance the purity of cancer cell isolation to about 77%.

A membrane oxygen electrode usually suffers from long-term signal deterioration due to environmental factors such as changes in hydrodynamic conditions and alteration of membrane oxygen diffusivity due to fouling. These problems can theoretically be overcome by the use of the same oxygen electrode in a pulsing mode. The effects of stirring rate, viscosity of the culture media, and addition of antifoam agents on the direct reading of this pulsing oxygen electrode were investigated, and the results were compared to the traditional pseudo-steady-state operation of the electrode. With a pulsing period controlled at 1 s and a rest period of longer than 5 min, the transient signal obtained can be quite stable, and it showed minimal interference from various environmental changes. Dissolved oxygen tension of a cephalosporin C fermentation was monitored using both this pulsing and the conventional pseudo-steady-state methods, and their readings were compared to those measured from an off-line newly calibrated oxygen electrode. The reading from the pulsed electrode showed more favorable agreement with that of the off-line measurement. The error encountered in using the conventional method of dissolved oxygen measurement could vary as much as 40% in comparison with the actual dissolved oxygen tension during a fermentation process.

A kinetic model of ethanol fermentation with inhibition of substrate and product at various temperatures was proposed. The effect of temperature on the kinetic behavior of Zymomonas mobilis ATCC 29191 was investigated by carrying out a series of ethanol fermentations. The following results were obtained: ( 1 ) Both μ and Q tended to decrease with initial glucose concentrations above 100 g l −1 . ( 2 ) μ m increased with temperature increase from 30 to 37°C, and decreased at temperatures above 37°C. Q m increased with temperature increase from 30 to 40°C. ( 3 ) P m and P ′ m decreased with an increa of temperature. ( 4 ) Retardation of variation of μ and Q as affected by ethanol concentration increased with temperature. ( 5 ) The kinetics of ethanol fermentation for Z. mobilis at temperatures ranging from 30 to 40°C can be simulated fairly well with the proposed model.