Mobile-centric ambient intelligence in health- and homecare-anticipating ethical and legal challenges

Ambient Intelligence provides the potential for vast and varied applications, bringing with it both promise and peril. The development of Ambient Intelligence applications poses a number of ethical and legal concerns. Mobile devices are increasingly evolving into tools to orientate in and interact with the environment, thus introducing a user-centric approach to Ambient Intelligence. The MINAmI (Micro-Nano integrated platform for transverse Ambient Intelligence applications) FP6 research project aims at creating core technologies for mobile device based Ambient Intelligence services. In this paper we assess five scenarios that demonstrate forthcoming MINAmI-based applications focusing on healthcare, assistive technology, homecare, and everyday life in general. A legal and ethical analysis of the scenarios is conducted, which reveals various conflicting interests. The paper concludes with some thoughts on drafting ethical guidelines for Ambient Intelligence applications.

A multi-D-shaped optical fiber for refractive index sensing

A novel class of multi-D-shaped optical fiber suited for refractive index measurements is presented. The multi-D-shaped optical fiber was constructed by forming several D-sections in a multimode optical fiber at localized regions with femtosecond laser pulses. The total number of D-shaped zones fabricated could range from three to seven. Each D-shaped zone covered a sensor volume of 100 μm depth, 250 μm width, and 1 mm length. The mean roughness of the core surface obtained by the AFM images was 231.7 nm, which is relatively smooth. Results of the tensile test indicated that the fibers have sufficient mechanical strength to resist damage from further processing. The multi-D-shaped optical fiber as a high sensitive refractive-index sensor to detect changes in the surrounding refractive index was studied. The results for different concentrations of sucrose solution show that a resolution of 1.27 × 10(-3)-3.13 × 10(-4) RIU is achieved for refractive indices in the range of 1.333 to 1.403, suggesting that the multi-D-shaped fibers are attractive for chemical, biological, and biochemical sensing with aqueous solutions.

Label-free and highly sensitive optical imaging of detailed microcirculation within meninges and cortex in mice with the cranium left intact

We demonstrate for the first time that the detailed blood flow distribution within intracranial dura mater and cortex can be visualized by an ultrahigh sensitive optical microangiography (UHS-OMAG). The study uses an UHS-OMAG system operating at 1310 nm with an imaging speed at 150 frames per second that requires approximately 10 s to complete one 3-D scan of approximately 2.5 x 2.5 mm(2). The system is sensitive to blood flow with a velocity ranging from approximately 4 microms to approximately 23 mms. We show superior performance of UHS-OMAG in providing functional images of capillary level microcirculation within meninges in mice with the cranium left intact, the results of which correlate well with the standard dural histopathology.

[Bioactivity of micro/nanostructural layers on titanium surfaces]

Porous surfaces have an important effect on bioactivity of titanium implants. In this study, two micro/nanostructural titanium surfaces were prepared by chemical and electrochemical method. The two samples had different diameters of nanotubes. Tests of biomineralization and codeposition in simulated body fluid and bovine serum albumin (BSA) were carried out in order to evaluate the bioactivity of micro/nanostructural titanium surfaces. The information of the surfaces was detected using scanning electron microscope and X-ray diffractometer. The results showed that the bioactivity of micro/nanostructural titanium increased with the diameter of nanotubes. Furthermore, the existence of BSA can accelerate biomineralization and decrease the crystallinity of hydroxyapatite coating.

Digital electrospray for controlled deposition

Many novel functional structures are now fabricated by controlled deposition as a maskless, bottom-up fabrication technique. These applications require rapid and precise deposition of minute amounts of solutions/suspensions or their ultimate particle products in predefined patterns. The electrospray is a promising alternative to the commonly used inkjet printing because it can easily handle highly viscous liquid, avoid high shear rates, and has low risk of clogging. We demonstrate a proof-of-concept digital electrospray. This system consists of a 61-nozzle array microfabricated in silicon and a 61-element digital extractor fabricated using flexible polyimide substrates. "Digital" refers to the state of each electrospray source that can be tuned either on or off independently and responsively. We showed a resolution of 675 mum and a response frequency up to 100 Hz. With similar design and industry standard fabrication procedures, it is feasible to scale up the system to O(1000) sources with spatial resolution better than 250 mum and a O(kHz) response frequency. The latter is controlled by the viscous damping time.

Free-standing lipid bilayers in silicon chips-membrane stabilization based on microfabricated apertures with a nanometer-scale smoothness

In the present study, we propose a method for preparing stable free-standing bilayer lipid membranes (BLMs). The BLMs were prepared in a microfabricated aperture with a smoothly tapered edge, which was prepared in a nanometer-thick Si(3)N(4) septum by the wet etching method. Owing to this structure, the stress on lipid bilayers at the contact with the septum was minimized, leading to remarkable membrane stability. The BLMs were not broken by applying a constant voltage of +/-1 V. The membrane lifetime was 15-45 h with and without an incorporated gramicidin channel. Gramicidin single-channel currents were recorded from the same BLM preparation when the aqueous solutions surrounding the BLM were repeatedly exchanged, demonstrating the tolerance of the present BLM to repetitive solution exchanges. Such stable membranes enable analysis of channel functions under various solution conditions from the same BLM, which will open up a variety of applications including a high throughput drug screening for ion channels.

In situ crystallized zirconium phenylphosphonate films with crystals vertically to the substrate and their hydrophobic, dielectric, and anticorrosion properties

The in situ crystallization technique has been utilized to fabricate zirconium phenylphosphonate (ZrPP) films with their hexagonal crystallite perpendicular to the copper substrate. The micro/nano roughness surface structure, as well as the intrinsic hydrophobic characteristic of the surface functional groups, affords ZrPP films excellent hydrophobicity with water contact angle (CA) ranging from 134 degrees to 151 degrees , without any low-surface-energy modification. Particularly, in the corrosive solutions such as acidic or basic solutions over a wide pH from 2 to 12, no obvious fluctuation in CA was observed for all the ZrPP film. The k values of the hydrophobic ZrPP films are in the low-k range (k < 3.0), meeting the development of ultra-large-scale integration (ULSI) circuits. The hydrophobicity feature is proposed to bear ZrPP film a more stable low-k value in an ambient atmosphere. Besides, the polarization current of ZrPP films is reduced by 2 orders of magnitude, compared to that of the untreated copper substrate. Even deposited in a vacuum oven for 30 days at room temperature, ZrPP films also show excellent corrosion resistance, indicating a stable anticorrosion property.

The expanding world of small molecule microarrays

Speed and throughput are vital ingredients for discovery-driven, "-omics" research. The small molecule microarray is one such platform, which delivers phenomenal screening throughput and capabilities. The concept at the heart of the technology is elegant, yet simple: by presenting large collections of molecules at a high density on a flat surface, one is able to interrogate them quickly and conveniently, evaluating all possible interactions in a single step. SMMs have, over the last decade, been established as a robust platform for screening, lead discovery, and molecular characterization. In this chapter, we describe the ways in which microarrays have been constructed and applied, focusing on the practical challenges faced when designing and performing SMM experiments. This is written as an introduction for new readers to the field, explaining the key principles and laying the foundation for the chapters that follow.

Real-time diffuse optical tomography based on structured illumination

A new optical acquisition scheme based on a pair of digital micromirror devices is developed and applied to three-dimensional tomographic imaging of turbid media. By using pairs of illumination-detection patterns with a single detector, we were able to perform high-resolution quantitative volumetric imaging of absorption heterogeneities embedded in optically thick samples. Additionally, a tomographic reconstruction algorithm was implemented on a graphical processor unit to provide optical reconstructions at a frame rate of 2 Hz. The structured illumination method proposed in this work has significant cost advantages over camera systems, as only a single detector is required. This configuration also has the potential to increase frame rate.

A peptide microarray for detecting protein kinase activity in cell lysates

Protein kinases (PKs) are widely recognized as valuable targets for disease diagnosis and drug discovery. For this reason, we have developed a sensitive peptide microarray for detecting intracellular PK activity. Peptides are immobilized on a glutaraldehyde-premodified high-amino terminal glass slide, by spotting 2 nL volumes of substrate peptide solutions with an automated microarray spotter. After the peptides are phosphorylated by cell lysates, phosphorylation is specifically recognized by a fluorescence-labeled antiphosphotyrosine antibody for tyrosine kinases, or Phos-tag biotin (a biotinylated phosphate-specific ligand based on Zn(2+) complex), which is subsequently bound with fluorescence-labeled streptavidin, for serine/threonine kinases. The fluorescence signal is then detected by an automatic microarray scanner. The peptide microarray system involves simple peptide immobilization, requires low sample volumes and provides a high density array. Importantly, it provides high sensitivity for detecting PK activities in cell lysates. Thus, the peptide microarray system is expected to be useful for a high-throughput kinase assay to investigate intracellular kinase activity and has potential applications in disease diagnosis and drug discovery.

High-pressure on-chip mechanical valves for thermoplastic microfluidic devices

A facile method enabling the integration of elastomeric valves into rigid thermoplastic microfluidic chips is described. The valves employ discrete plugs of elastomeric polydimethylsiloxane (PDMS) integrated into the thermoplastic substrate and actuated using a threaded stainless steel needle. The fabrication process takes advantage of poly(ethylene glycol) (PEG) as a sacrificial molding material to isolate the PDMS regions from the thermoplastic flow channels, while yielding smooth contact surfaces with the PDMS valve seats. The valves introduce minimal dead volumes, and provide a simple mechanical means to achieve reproducible proportional valving within thermoplastic microfluidic systems. Burst pressure tests reveal that the valves can withstand pressures above 12 MPa over repeated open/close cycles without leakage, and above 24 MPa during a single use, making the technology well suited for applications such as high performance liquid chromatography. Proportional valve operation is demonstrated using a multi-valve chemical gradient generator fabricated in cyclic olefin polymer.

Microfluorimeter with disposable polymer chip for detection of coeliac disease toxic gliadin

Coeliac disease is an inflammatory disease of the upper small intestine and results from gluten ingestion in genetically susceptible individuals, and is the only life-long nutrient-induced enteropathy. The only treatment is a strict gluten-free diet and the longer the individual fails to adhere to this diet, the greater the chance of developing malnutrition and other complications. The existence of reliable gluten free food is crucial to the well-being of the population. Here we report on a microfluorimeter device for the in situ detection of gliadin in foodstuffs, which could be used for a rapid control of raw materials in food processing, as well as for process control of gliadin contamination. The microfluorimeter is based on a reflector that is used inside a microfluidic chip, exploiting various strategically placed reflective or totally metallised mirrors for efficient collection of the fluorescent light emitted in a large solid angle. The chip is capable of executing five assays in parallel and has been demonstrated to possess detection sensitivity applicable to fluoroimmunoassays. Various immunoassay formats exploiting fluorescence detection, using enzyme/fluorophore labels were developed and compared in terms of sensitivity, ease of assay, assay time and compatibility with buffer used to extract gliadin from raw and cooked foodstuffs, with the best performance observed with an indirect competition assay using a fluorophore-labelled anti-mouse antibody. This assay was exploited within the microfluorimeter device, and a very low detection limit of 4.1 ng/mL was obtained. The system was observed to be highly reproducible, with an RSD of 5.9%, for a concentration of 50 ng/mL of gliadin applied to each of the five channels of the microfluorimeter. Biofunctionalised disposable strips incorporated into the microfluorimeter were subjected to accelerated Arrhenius thermal stability studies and it was demonstrated that strips pre-coated with gliadin could be stored for approximately 2 years at 4 degrees C, with no discernable loss in sensitivity or detectability of the assay. Finally, the microfluorimeter was applied to the analysis of commercial gluten-free food samples, and an excellent correlation with routine ELISA measurements was obtained. The developed microfluorimeter should find widespread application for on-site execution of fluoroimmunoassays.

A blood sampling microsystem for pharmacokinetic applications: design, fabrication, and initial results

This paper describes a microsystem for automated blood sampling from laboratory mice used in pharmacokinetic studies. Intended to be mounted as a "backpack" on a mouse, it uses a microneedle, reservoir, and an actuator to instantaneously prick the animal for a time-point sample, eliminating the need for a tethered catheter with large dead volume. The blood is collected by capillary effect through a 31-33 gauge microneedle (250-210 microm OD) into a approximately 1 microL micromachined steel reservoir. The voice coil actuator provides a peak force of approximately 300 mN, which amply exceeds the measured piercing force of mouse skin (i.e., 60-85 mN for a 31-gauge needle with 12 degrees bevel). The sampling system was tested in vitro using a mock vessel with adjustable pressure; the reservoir was filled in <0.15 s by a combination of the capillary effect and blood pressure. The system may also be used to sample interstitial fluid, but the absence of blood pressure makes it necessary to enhance the capillary effect of the needle. This is accomplished by either electropolishing the inner surface to make it more hydrophilic or using a polymer wire insert to increase the surface area. The steel surface of the reservoir is also coated with silicon oxynitride by plasma-enhanced chemical vapor deposition to improve its hydrophilicity. Blood from fresh bovine tissue was collected into the reservoir to simulate interstitial fluid sampling. In vivo tests on live, anesthetized mice resulted in successful collection of blood into the reservoir. The possible integration of the device in microanalytical systems and the device scalability for multisampling are discussed.

Highly parallel introduction of nucleic acids into mammalian cells grown in microwell arrays

High-throughput cell-based screens of genome-size collections of cDNAs and siRNAs have become a powerful tool to annotate the mammalian genome, enabling the discovery of novel genes associated with normal cellular processes and pathogenic states, and the unravelling of genetic networks and signaling pathways in a systems biology approach. However, the capital expenses and the cost of reagents necessary to perform such large screens have limited application of this technology. Efforts to miniaturize the screening process have centered on the development of cellular microarrays created on microscope slides that use chemical means to introduce exogenous genetic material into mammalian cells. While this work has demonstrated the feasibility of screening in very small formats, the use of chemical transfection reagents (effective only in a subset of cell lines and not on primary cells) and the lack of defined borders between cells grown in adjacent microspots containing different genetic material (to prevent cell migration and to aid spot location recognition during imaging and phenotype deconvolution) have hampered the spread of this screening technology. Here, we describe proof-of-principles experiments to circumvent these drawbacks. We have created microwell arrays on an electroporation-ready transparent substrate and established procedures to achieve highly efficient parallel introduction of exogenous molecules into human cell lines and primary mouse macrophages. The microwells confine cells and offer multiple advantages during imaging and phenotype analysis. We have also developed a simple method to load this 484-microwell array with libraries of nucleic acids using a standard microarrayer. These advances can be elaborated upon to form the basis of a miniaturized high-throughput functional genomics screening platform to carry out genome-size screens in a variety of mammalian cells that may eventually become a mainstream tool for life science research.

Single-anchor support and supercritical CO2 drying enable high-precision microfabrication of three-dimensional structures

In high-precision two-photon microfabrication of three-dimensional (3-D) polymeric microstructures, supercritical CO(2) drying was employed to reduce surface tension, which tends to cause the collapse of micro/nano structures. Use of supercritical drying allowed high-aspect ratio microstructures, such as micropillars and cantilevers, to be fabricated. We also propose a single-anchor supporting method to eliminate non-uniform shrinkage of polymeric structures otherwise caused by attachment to the substrate. Use of this method permitted frame models such as lattices to be produced without harmful distortion. The combination of supercritical CO(2) drying and the single-anchor supporting method offers reliable high-precision microfabrication of sophisticated, fragile 3-D micro/nano structures.

Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 microm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 degrees can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

Microneedle arrays allow lower microbial penetration than hypodermic needles in vitro

METHODS

In this study we determined, for the first time, the ability of microorganisms to traverse microneedle-induced holes using two different in vitro models.

RESULTS

When employing Silescol membranes, the numbers of Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis crossing the membranes were an order of magnitude lower when the membranes were punctured by microneedles rather than a 21G hypodermic needle. Apart from the movement of C. albicans across hypodermic needle-punctured membranes, where 40.2% of the microbial load on control membranes permeated the barrier over 24 h, the numbers of permeating microorganisms was less than 5% of the original microbial load on control membranes. Experiments employing excised porcine skin and radiolabelled microorganisms showed that the numbers of microorganisms penetrating skin beyond the stratum corneum were approximately an order of magnitude greater than the numbers crossing Silescol membranes in the corresponding experiments. Approximately 10(3) cfu of each microorganism adhered to hypodermic needles during insertion. The numbers of microorganisms adhering to MN arrays were an order of magnitude higher in each case.

CONCLUSION

We have shown here that microneedle puncture resulted in significantly less microbial penetration than did hypodermic needle puncture and that no microorganisms crossed the viable epidermis in microneedle-punctured skin, in contrast to needle-punctured skin. Given the antimicrobial properties of skin, it is, therefore, likely that application of microneedle arrays to skin in an appropriate manner would not cause either local or systemic infection in normal circumstances in immune-competent patients. In supporting widespread clinical use of microneedle-based delivery systems, appropriate animal studies are now needed to conclusively demonstrate this in vivo. Safety in patients will be enhanced by aseptic or sterile manufacture and by fabricating microneedles from self-disabling materials (e.g. dissolving or biodegradable polymers) to prevent inappropriate or accidental reuse.

Refractive index sensor based on a microhole in single-mode fiber created by the use of femtosecond laser micromachining

A compact in-fiber refractive index (RI) sensor is presented that is based on a microhole created in a conventional single-mode fiber by the use of femtosecond laser micromachining. The transmission properties of such a device with a microhole of different diameters have been investigated in the wavelength region of 1500-1600 nm and in the RI range of 1.30-1.45. It is found that the relationship between the transmission and the RI is critically dependent on the size of the microhole in the fiber core region. The highest resolution obtained is 6.70x10(-5), in the RI range of 1.37-1.42, when the microhole diameter is approximately 8 microm, close to the fiber core size. The in-fiber RI sensor developed in this work is easy to fabricate and can be used to implement temperature-independent measurements.

Acoustic tweezers: patterning cells and microparticles using standing surface acoustic waves (SSAW)

Here we present an active patterning technique named "acoustic tweezers" that utilizes standing surface acoustic wave (SSAW) to manipulate and pattern cells and microparticles. This technique is capable of patterning cells and microparticles regardless of shape, size, charge or polarity. Its power intensity, approximately 5x10(5) times lower than that of optical tweezers, compares favorably with those of other active patterning methods. Flow cytometry studies have revealed it to be non-invasive. The aforementioned advantages, along with this technique's simple design and ability to be miniaturized, render the "acoustic tweezers" technique a promising tool for various applications in biology, chemistry, engineering, and materials science.

A novel permalloy based magnetic single cell micro array

Devices capable of automatically aligning cells onto geometrical arrays are of great interest to biomedical researchers. Such devices can facilitate the study of numerous cells while the cells remain physically separated from one another. In this way, cell arrays reduce cell-to-cell interactions while the cells are all subjected to common stimuli, which allows individual cell behaviour to be revealed. The use of arrays allows for the parallel analysis of single cells, facilitates data logging, and opens the door to the use of automated machine-based single cell analysis techniques. A novel permalloy based magnetic single cell micro array (MSCMA) is presented in this paper. The MSCMA creates an array of magnetic traps by generating magnetic flux density peaks at predefined locations. When using cells labelled with immunomagnetic labels, the cells will interact with the magnetic fields, and can be captured at the magnetic trap sites. Prototypes of the MSCMA have been successfully fabricated and tested using both fixed and live Jurkat cells (10 microm average diameter) that were labelled. The prototypes performed as predicted during experimental trials. The experimental results show that the MSCMA can randomly array up to 136 single cells per square mm. The results also show that the number of single cells captured is a function of the trap site density of the MSCMA design and the cell density in the fluid sample.

Passive flow-rate regulators using pressure-dependent autonomous deflection of parallel membrane valves

We present passive flow-rate regulators using an autonomous deflection of parallel membrane valves, capable to maintain a constant flow-rate at varying inlet pressure supplied from micropumps. The previous passive flow-rate regulators are difficult to integrate with micropumps, not only because of the complex multi-layer structures, but also because of the high threshold inlet pressure required for flow-rate regulation. In this study, we present passive flow-rate regulators using parallel membrane valves, capable of achieving flow-rate regulation function at the minimum threshold inlet pressure as low as 15 kPa with simple structure formed by a single mask process. The parallel membranes in a flow-rate regulator are designed to deflect and adjust flow resistance autonomously according to the inlet pressure, thus maintaining a constant flow-rate independent of the inlet pressure variation. We designed the four different prototypes of W20, W30, W40, and W50, having parallel membrane widths of 20, 30, 40 and 50 microm, respectively. We estimated the flow-rate based on both analytical and numerical models. In an experimental study, we observed the deformation of parallel membranes and the flow-rate depending on the inlet pressure. The fabricated prototypes achieved the constant flow-rate of 6.09 +/- 0.32 microl s(-1) (W20 fabricated by 10 : 1 PDMS (PolyDiMethylSiloxane)) over an inlet pressure of 20 kPa. We also observed that prototypes fabricated by 20 : 1 PDMS, having lower Young's modulus than normal 10 : 1 PDMS, showed a lower threshold pressure and higher regulated flow-rate than prototypes fabricated by 10 : 1 PDMS. W40 fabricated by 20 : 1 PDMS showed a constant flow-rate of 14.53 +/- 0.51 microl s(-1) over inlet pressure of 15 kPa. The present passive flow-rate regulators have strong potential for applications in integrated microfluidic systems.

Free jet micromixer to study fast chemical reactions by small angle X-ray scattering

We present the design, fabrication process, and the first test results of a high aspect ratio micromixer combined with a free jet for under 100 micros time resolved studies of chemical reactions. The whole system has been optimized for synchrotron small angle X-ray scattering (SAXS) experiments. These studies are of particular interest to understand the early stages of chemical reactions, such as the kinetics of nanoparticle formation. The mixer is based on hydrodynamic focusing and works in the laminar regime. The use of a free jet overcomes the fouling of the channels and simultaneously circumvents background scattering from the walls. The geometrical parameters of the device have been optimized using finite element simulations, resulting in smallest features with radius <1 microm, and a channel depth of 60 microm, thus leading to an aspect ratio >60. To achieve the desired dimensions deep X-ray lithography (DXRL) has been employed. The device has been tested. First the focusing effect has been visualized using fluorescein. Then the evolution and stability of the jet, which exits the mixer nozzle at 13 m s(-1), have been characterized. Finally SAXS measurements have been conducted of the formation of calcium carbonate from calcium chloride and sodium carbonate. The fastest measurement is 75 micros after the beginning of the mixing of the reagents. The nanostructural evolution of chemical reactions is clearly discernible.

"Smart dust" biosensors powered by biomolecular motors

The concept of a microfabricated biosensor for environmental and biomedical monitoring applications which is composed of environmentally benign components is presented. With a built-in power source (the biological fuel ATP) and driven by biological motors (kinesin), sensing in the microdevice can be remotely activated and the presence of a target molecule or toxin remotely detected. The multifaceted progress towards the realization of such a device is described.