A textile-based platform for real-time sweat collection and analysis

The ability to perform real-time chemical measurements of body fluids is an exciting concept for the healthcare sector and the sports industry. This work is part of the BIOTEX project, an EU FP6 project which involved the development of textile-based sensors to measure the chemical composition of sweat. This is a challenging task involving the collection of sweat samples, delivery to an active surface and the removal of waste products. A textile based platform which would be in immediate contact with the skin was developed for this purpose. The system uses capillary action and exhibits a passive pumping mechanism. This is achieved by using a combination of moisture wicking fabric and a highly absorbent material. A fabric channel is created for the integration of sensors. The channel is produced using a mask and screen-printing hydrophobic material onto the fabric. Different channel lengths and widths affect the flow rate of the system. The channel dimensions were designed based on typical sweat rates and also to accommodate sensor placement. A textile patch was developed and integrated into a waistband for collection of sweat on the lower back. Real-time measurements of sweat pH, sodium concentration, conductivity and temperature were measured during exercise using the textile patch

BIOTEX-biosensing textiles for personalised healthcare management.

Textile-based sensors offer an unobtrusive method of continually monitoring physiological parameters during daily activities. Chemical analysis of body fluids, noninvasively, is a novel and exciting area of personalized wearable healthcare systems. BIOTEX was an EU-funded project that aimed to develop textile sensors to measure physiological parameters and the chemical composition of body fluids, with a particular interest in sweat. A wearable sensing system has been developed that integrates a textile-based fluid handling system for sample collection and transport with a number of sensors including sodium, conductivity, and pH sensors. Sensors for sweat rate, ECG, respiration, and blood oxygenation were also developed. For the first time, it has been possible to monitor a number of physiological parameters together with sweat composition in real time. This has been carried out via a network of wearable sensors distributed around the body of a subject user. This has huge implications for the field of sports and human performance and opens a whole new field of research in the clinical setting

Stereocontrol of all-carbon quaternary centers through enantioselective desymmetrization of meso primary diols by organocatalyzed acyl transfer

International audienceThe symmetry breaking of meso primary diols bearing a tetrahydropyran ring was employed, using catalytic asymmetric acyl transfer, to control all-carbon quaternary stereocenters. The planar chiral Fu DMAP catalyst was used in this reaction to reach a high degree of enantioselectivity (up to 97:3 e.r.) through a synergic effect combining a desymmetrization step and a kinetic resolution. Moreover, a beneficial effect was exhibited by C6F6 solvent, yielding the first example of an organocatalyzed asymmetric acyl transfer. The desymmetrized monoesters were then used to obtain, after a straightforward ring opening sequence, complex polyketide building blocks bearing all-carbon quaternary stereocenter

Double Catalytic Kinetic Resolution (DoCKR) of Acyclic anti-1,3-Diols: The Additive Horeau Amplification

International audienceThe concept of a synergistic double catalytic kinetic resolution (DoCKR) as described in this article was successfully applied to racemic acyclic anti-1,3-diols, a common motif in natural products. This process takes advantage of an additive Horeau amplification involving two successive enantioselective organocatalytic acylation reactions, and leads to diesters and recovered diols with high enantiopurities. It was first developed with C 2-symmetrical diols and then further extended to non-C 2-symmetrical anti diols to prepare useful chiral building blocks. The protocol is highly practical as it only requires 1 mol % of a commercially available organocatalyst and leads to easily separable products. This procedure was applied to the shortest reported total synthesis of (+ +)-cryptocaryalactone, a natural product with anti-germinative activity

Highly Enantioselective Acylation of Acyclic Meso 1,3-Diols through Synergistic Isothiourea-Catalyzed Desymmetrization/Chiroablative Kinetic Resolution

International audienceA general and highly efficient organocatalyzed desymmetrization of acyclic meso 1,3-diols through acyl transfer using chiral isothioureas is described. The introduction of π-systems in the acyclic substrates provided new opportunities in terms of reactivity, enantioselectivity and synthetic potential. To reach this high level of enantioselectivity (up to er >99:1), the reaction proceeds through a synergistic mechanism involving a desymmetrization reaction and a chiroablative kinetic resolution process. This methodology was used with success as the sole enantioselective catalytic step (developed on a gram scale) to achieve the total synthesis of the antiosteoporotic diarylheptanoid (−)-diospongin A (7 steps)

Spatially resolved acyl transfer on surface by organo-catalytic scanning probe nanolithography (o-cSPL)

International audienceGroundbreaking research done in the area of nanolithography makes it a versatile tool to produce nanopatterns for a broad range of chemical surface functionalization or physical modifications. We report for the first time an organocatalytic scanning probe nanolithography (o-cSPL) approach. Covalent binding of an organocatalyst on the apex of an atomic force microscope (AFM) tip gives way to a system that allows the formation of locally defined acylated-alcohol patterns on self-assembled monolayers (SAMs). With resolutions comparable to those of other cSPL methods, this first example of o-cSPL holds promise for future applications of bottom-up nanolithography setups employing this novel technique

Spatially resolved acyl transfer on surface by organo-catalytic scanning probe nanolithography (o-cSPL)

Groundbreaking research done in the area of nanolithography makes it a versatile tool to produce nanopatterns for a broad range of chemical surface functionalization or physical modifications. We report for the first time an organocatalytic scanning probe nanolithography (o-cSPL) approach. Covalent binding of an organocatalyst on the apex of an atomic force microscope (AFM) tip gives way to a system that allows the formation of locally defined acylated-alcohol patterns on self-assembled monolayers (SAMs). With resolutions comparable to those of other cSPL methods, this first example of o-cSPL holds promise for future applications of bottom-up nanolithography set-ups employing this novel technique

Catalytic Scanning Probe Nanolithography (cSPL): Control of the AFM Parameters in Order to Achieve Sub-100-nm Spatially Resolved Epoxidation of Alkenes Grafted onto a Surface

International audienceScanning probe lithography (SPL) appears to be a reliable alternative to the use of masks in traditional lithography techniques as it offers the possibility of directly producing specific chemical functionalities with nanoscale spatial control. We have recently extend the range of applications of catalytic SPL (cSPL) by introducing a homogeneous catalyst immobilized on the apex of a scanning probe. Here we investigate the importance of atomic force microscopy (AFM) physical parameters (applied force, writing speed, and interline distance) on the resultant chemical activity in this cSPL methodology through the direct topographic observation of nanostructured surfaces. Indeed, an alkene-terminated self-assembled monolayer (alkene-SAM) on a silicon wafer was locally epoxidized using a scanning probe tip with a covalently grafted manganese complex bearing the 1,4,7-triazacyclononane macrocycle as the ligand. In a post-transformation process, N-octylpiperazine was covalently grafted to the surface via a selective nucleophilic ring-opening reaction. With this procedure, we could write various patterns on the surface with high spatial control. The catalytic AFM probe thus appears to be very robust because a total area close to 500 μm2 was patterned without any noticeable loss of catalytic activity. Finally, this methodology allowed us to reach a lower lateral line resolution down to 40 nm, thus being competitive and complementary to the other nanolithographical techniques for the nanostructuration of surface

Highly Enantioselective Acylation of Acyclic <i>Meso</i> 1,3-Diols through Synergistic Isothiourea-Catalyzed Desymmetrization/Chiroablative Kinetic Resolution

A general and highly efficient organocatalyzed desymmetrization of acyclic meso 1,3-diols through acyl transfer using chiral isothioureas is described. The introduction of π-systems in the acyclic substrates provided new opportunities in terms of reactivity, enantioselectivity and synthetic potential. To reach this high level of enantioselectivity (up to er >99:1), the reaction proceeds through a synergistic mechanism involving a desymmetrization reaction and a chiroablative kinetic resolution process. This methodology was used with success as the sole enantioselective catalytic step (developed on a gram scale) to achieve the total synthesis of the antiosteoporotic diarylheptanoid (−)-diospongin A (7 steps)