Impact of anti-fingerprint coatings on the detection of fingermarks

This study discusses the deposition and behavior of fingermark residue (eccrine, sebum-rich, and natural) on anti-fingerprint (AFP) coatings as well as the impact of these coatings on conventional detection techniques (cyanoacrylate fuming, small particle reagent, vacuum metal deposition). The preliminary conclusions show that (1) AFP coatings do not prevent the deposition of secretion residue, (2) the amphiphobic properties of AFP coatings may benefit the preservation and observation of latent marks, (3) AFP coatings do not hinder the application of conventional detection techniques, and (4) the impact of AFP coatings on ridge clarity is overall positive or limited, with differences of behavior between plastic-based coatings (negative impact mostly) and glass-based ones (positive impact mostly)

Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor

This paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique. The device was evaluated experimentally and its overall performance compared with a commercial silicon-based pressure sensor. Furthermore, the device use was demonstrated by measuring blood pressure and heart rate in viv

Smart Knee Prosthesis for Orthopedic Surgery: the implantable and wearable Measurement System

Recent advances in remote powering and telemetry permitted the use of sensors inside body. A few studies have been already done on smart knee prostheses, but all focused on monitoring the in-vivo contact forces and moments. A smart design, compatible with mechanical structure of commercially-available knee prostheses, that provides force and accurate kinematics feedback was suggested with all electronics housed in the polyethylene insert (PE). The current work addresses the designed kinematics and force measurement system of that smart implant and its validation in a robotic knee simulator

Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor.

This paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique. The device was evaluated experimentally and its overall performance compared with a commercial silicon-based pressure sensor. Furthermore, the device use was demonstrated by measuring blood pressure and heart rate in vivo

Separation of blood microsamples by exploiting sedimentation at the microscale.

Microsample analysis is highly beneficial in blood-based testing where cutting-edge bioanalytical technologies enable the analysis of volumes down to a few tens of microliters. Despite the availability of analytical methods, the difficulty in obtaining high-quality and standardized microsamples at the point of collection remains a major limitation of the process. Here, we detail and model a blood separation principle which exploits discrete viscosity differences caused by blood particle sedimentation in a laminar flow. Based on this phenomenon, we developed a portable capillary-driven microfluidic device that separates blood microsamples collected from finger-pricks and delivers 2 µL of metered serum for bench-top analysis. Flow cytometric analysis demonstrated the high purity of generated microsamples. Proteomic and metabolomic analyses of the microsamples of 283 proteins and 1351 metabolite features was consistent with samples generated via a conventional centrifugation method. These results were confirmed by a clinical study scrutinising 8 blood markers in obese patients

Microdevice for Sedimentation-based Separation of Blood Microsamples at the Point of Collection

Laboratory blood testing plays a central role in current diagnostics and therapeutical decisions. Thus, errors have a direct impact on care quality and cost. The majority of errors occur in the pre-analytical phase, when samples are collected, stored and prepared. For biochemical analysis, the most common preparation operation is the separation of blood plasma: performing this operation upon sampling has the potential to simplify and render the testing cycle more reliable. Hence, in this work, a microdevice that performs blood separation at the point of collection is presented. The capillary-driven microdevice processes fingerprick blood microsamples without the need for external equipment. The device relies on sedimentation as a simple and spontaneous driving force for the separation of undiluted whole blood. Blood flows in the device at a velocity allowing cells to settle on the bottom of a constant height channel and create a higher viscosity liquid fraction. The supernatant plasma of lower viscosity is pumped at a higher speed than the sediment in the device. Thus, as the device fills, a plasma plug is generated in the downstream section of the channel. In this work, a unidimensional model of combining Kynch sedimentation and Poiseuille flow theories is established to describe this novel separation phenomenon. The impact of design and blood parameters on the separation is studied. The device can be used to separate fresh or anti-coagulated samples obtained through skin puncture. For both sample natures, the cell-free plug appears after a separation delay of 400 s. This delay is necessary to establish a sufficient viscosity contrast through sedimentation. Subsequently, for anti-coagulated samples, cellfree liquid is extracted with a 17 % yield. For fresh samples, coagulation leads to an increase of yield to 67 %. The combination of sedimentation and filtration through the clot are the reasons for this increase. Separated samples are retrieved from the chip through the use of an integrated ejection mechanism. The device is designed to eject a volume of 2ÎŒL of cell-free liquid out of 25ÎŒL of whole blood. The quality of separated samples was established by measuring particle contaminant concentration and proteomic profile. The contaminant concentration is lower and more repeatable than in centrifuged plasma or serum samples. In the protein profile, only 4.5% of quantified proteins show significantly different levels between serum and chip-separated samples - thus, showing that the separated samples and serum could be used interchangeably. The microdevice was combined with standard clinical automated analyzers to perform blood panels on 12 obese patients. Of the 8 blood markers analyzed, 7 markers showed significant correlation between the chip-separated and standard plasma samples. This shows that the microdevice can be used in combination with standard bench top analytical tools. The novel microdevice presented in this work paves the way to a family of microsystems that perform purely pre-analytical operations. The performance of the device, quality of retrieved samples and combinability with bench-top techniques indicate that the microdevice could impact on current testing cycles: the device could reduce the pre-analytical sources of errors by performing blood microsample separation at the point of collection

Influence of the materials magnetic state on the accurate determination of the magnetocaloric effect

In this paper, we report a detailed study of the magnetocaloric effect (MCE) in different first order magnetic transition (FOMT) materials with different situation of the magnetic state (magnetic order). For this purpose, R-Co2, MnAs based compounds were considered in this study. The MCE is discussed in terms of Maxwell relation (MR) and Clausius-Clapeyron (C-C) equation. The deviation observed between both methods is discussed and analyzed. On the other hand, practically all the reported data of the MCE in the literature are associated to the applied external magnetic field and have not been corrected taking into account the demagnetization effect related to the materials shape. The obtained results demonstrate that this phenomenon can alter drastically the MCE values by cancelling out a large part of the external field, resulting in spurious values of the measured MCE. The effect of the demagnetization field on the magnetocaloric performances is also the subject of this paper

Implantable and wearable measurement system for smart knee prosthesis

In this work we present the implantable and wearable measurement system developed for smart knee prostheses monitoring. The kinematic measurement system contains three anisotropic magnetoresistive sensors embedded into the polyethylene part of the prostheses. The kinematic measurement system also has two inertial measurement units to be worn by the subject on the shank and thigh. Each of this inertial measurement units consisted of a 3D accelerometer and a 3D gyroscope. The force measurement system contains implantable strain gauges that connected in two separate Wheatstone bridges and embedded in a designed capsule-like structure. These systems were validated in a robotic knee simulator against reference force and kinematics systems. The best angle estimator performed with an RMS error of 1.18°±0.25° over four different walking patterns, while the force sensors showed linear behavior in measuring the applied forces, where linear models obtained R2s larger than 0.98