Silver nanoparticles within functionalized hydrogels for plasmonic (bio)chemical sensors

Plasmonics is the basis for a novel generation of adsorption-based ultrasensitive (bio) chemical sensors. In nanoplasmonic sensors one utilizes nanocomposites typically in the form of thin films, comprising metal nanoparticles or ordered metal-dielectrics (plasmonic crystals). In this work we investigated thin functionalized hydrogel films with embedded silver nanoparticles. These films were prepared by copolymerizing glycidyl methacrylate with mono and multifunctional methacrylates using UV irradiation. The epoxy group in glycidyl methacrylate can then be converted by chemical means into a desired functionality to capture the targeted analyte. Silver nanoparticles were either photochemically generated in situ, or were introduced into hydrogels by chemical reduction. Differences in morphology and performance of these nanocomposites were investigated and will be discussed

Polarization control and sensing with two-dimensional coupled photonic crystal microcavity arrays

We have experimentally studied polarization properties of the two-dimensional coupled photonic crystal microcavity arrays, and observed a strong polarization dependence of the transmission and reflection of light from the structures - the effects that can be employed in building miniaturized polarizing optical components. Moreover, by combining these properties with a strong sensitivity of the coupled bands on the surrounding refractive index, we have demonstrated a detection of small refractive index changes in the environment, which is useful for construction of bio-chemical sensors.Comment: 8 pages text and 4 figures on 4 pages. Submitted for publication on 07/14/0

Unconventional Uses of Cantilevers for Chemical Sensing in Gas and Liquid Environments

Microcantilevers used as (bio)chemical sensors are usually coated with a chemically sensitive layer. The coated devices operate either in a static bending regime or in a dynamic flexural mode. While the coated devices operate generally well in both the static and dynamic mode, they do suffer from certain shortcomings depending on the medium of operation and the application, including lack of selectivity and of reversibility of the sensitive coating and a reduced quality factor due to the surrounding medium. In particular, the performance of microcantilevers excited in their standard out-of-plane dynamic mode drastically decreases in viscous liquid media. Moreover, the responses of coated cantilevers operating in the static bending mode are often difficult to interpret. To resolve those performance issues, unconventional uses of microcantilever are reviewed in this paper, which consist of the use of the dynamic mode without sensitive coating, the use of in-plane (flexural and longitudinal) vibration modes in liquid media, and fully accounting for the viscoelastic effects of the coatings in the static mode of operation. The advantages and drawbacks of these unconventional uses of microcantilevers for chemical sensing in gas and liquid environments are discussed

Wearable (bio)chemical sensors for applications in sport physiology

Nosivi bežični kemijski senzori omogućavaju neinvazivnu i kontinuiranu analizu uzoraka, što nije moguće postići klasičnim analitičkim metodama i instrumentima. U ovom radu predstavljena su mjerenja provedena kako bi se ustanovio princip djelovanja te mogućnost primjene novog nosivog optičkog senzora u fiziologiji sporta. Kolorimetrijska karakterizacija pH osjetljivog bojila (2-fluoro-4-[4-(2-hidroksietansulfonil)-fenilazo]-6-metoksifenol (GJM-492) imobiliziranog na tekstilu od poliestera, provedena je kako bi se odredila njegova primjenjivost za određivanje pH znoja. Senzor je zasnovan na RFID tehnologiji bežične komunikacije, te bi se ovakva vrsta senzora mogla primjenjivati kao nosivi bežični optički pH kemijski senzor u svrhu poboljšanja učinka sportaša.Wearable wireless chemical sensors allow non-invasive and continuous analysis of samples, which can otherwise not be achieved by conventional analytical methods and instruments. In this work measurments conducted in order to establish the principle of operation and possibility of application of a novel type of wearable optical chemical sensor in sport physiology are presented. Colourimetric characterisation of pH sensitive dye 2-fluoro-4-[4-(2-hydroxyethanesulfonyl)-phenylazo]-6-methoxyphenol (GJM-492) immobilized on a polyester fabric was conducted in order to determine its applicability for sweat pH monitoring. The wireless sensor is based on RFID technology of wireless communication, and this type of sensor could therefore be used as wearable wireless optical pH sensor in order to improve athletes' performance

Wearable (bio)chemical sensors for applications in sport physiology

Nosivi bežični kemijski senzori omogućavaju neinvazivnu i kontinuiranu analizu uzoraka, što nije moguće postići klasičnim analitičkim metodama i instrumentima. U ovom radu predstavljena su mjerenja provedena kako bi se ustanovio princip djelovanja te mogućnost primjene novog nosivog optičkog senzora u fiziologiji sporta. Kolorimetrijska karakterizacija pH osjetljivog bojila (2-fluoro-4-[4-(2-hidroksietansulfonil)-fenilazo]-6-metoksifenol (GJM-492) imobiliziranog na tekstilu od poliestera, provedena je kako bi se odredila njegova primjenjivost za određivanje pH znoja. Senzor je zasnovan na RFID tehnologiji bežične komunikacije, te bi se ovakva vrsta senzora mogla primjenjivati kao nosivi bežični optički pH kemijski senzor u svrhu poboljšanja učinka sportaša.Wearable wireless chemical sensors allow non-invasive and continuous analysis of samples, which can otherwise not be achieved by conventional analytical methods and instruments. In this work measurments conducted in order to establish the principle of operation and possibility of application of a novel type of wearable optical chemical sensor in sport physiology are presented. Colourimetric characterisation of pH sensitive dye 2-fluoro-4-[4-(2-hydroxyethanesulfonyl)-phenylazo]-6-methoxyphenol (GJM-492) immobilized on a polyester fabric was conducted in order to determine its applicability for sweat pH monitoring. The wireless sensor is based on RFID technology of wireless communication, and this type of sensor could therefore be used as wearable wireless optical pH sensor in order to improve athletes' performance

Fluctuations of the number of adsorbed molecules due to adsorption-desorption processes coupled with mass transfer and surface diffusion in bio/chemical MEMS sensors

A comprehensive theoretical model of the fluctuations of the number of adsorbed molecules in MEMS bio/chemical sensors is presented for the first time; the model takes into account the processes of mass transfer, adsorption and desorption, and surface diffusion of adsorbed molecules. The numerical calculations performed using the derived theory show that the influence of surface diffusion on the fluctuations spectrum is significant and that it also depends on the species of adsorbed molecules.\ud \ud Poster presented at the 39th International Conference on Micro and Nano Engineering MNE 2013, 16-19 September 2013, London, UK\u

Unconventional Uses of Microcantilevers as Chemical Sensors in Gas and Liquid Media

The use of microcantilevers as (bio)chemical sensors usually involves the application of a chemically sensitive layer. The coated device operates either in a static bending regime or in a dynamic flexural mode. While some of these coated devices may be operated successfully in both the static and the dynamic modes, others may suffer from certain shortcomings depending on the type of coating, the medium of operation and the sensing application. Such shortcomings include lack of selectivity and reversibility of the sensitive coating and a reduced quality factor due to the surrounding medium. In particular, the performance of microcantilevers excited in their standard out-of-plane dynamic mode drastically decreases in viscous liquid media. Moreover, the responses of coated cantilevers operating in the static bending mode are often difficult to interpret. To resolve these performance issues, the following emerging unconventional uses of microcantilevers are reviewed in this paper: (1) dynamic-mode operation without using a sensitive coating, (2) the use of in-plane vibration modes (both flexural and longitudinal) in liquid media, and (3) incorporation of viscoelastic effects in the coatings in the static mode of operation. The advantages and drawbacks of these atypical uses of microcantilevers for chemical sensing in gas and liquid environments are discussed

Silver nanoparticles within functionalized hydrogels for plasmonic (bio)chemical sensors

Plasmonics is the basis for a novel generation of adsorption-based ultrasensitive (bio) chemical sensors. In nanoplasmonic sensors one utilizes nanocomposites typically in the form of thin films, comprising metal nanoparticles or ordered metal-dielectrics (plasmonic crystals). In this work we investigated thin functionalized hydrogel films with embedded silver nanoparticles. These films were prepared by copolymerizing glycidyl methacrylate with mono and multifunctional methacrylates using UV irradiation. The epoxy group in glycidyl methacrylate can then be converted by chemical means into a desired functionality to capture the targeted analyte. Silver nanoparticles were either photochemically generated in situ, or were introduced into hydrogels by chemical reduction. Differences in morphology and performance of these nanocomposites were investigated andwill be discussed

Sensors as green tools in analytical chemistry

Altres ajuts: Acord transformatiu CRUE-CSICThis article comments on green aspects of (bio)chemical sensors for qualitative and quantitative analysis applications. First, the aspects that connect chemical sensors and biosensors with the main trends of green analytical chemistry are discussed. To continue, a set of paradigmatic examples of sustainable assays pertaining to the (bio)sensing field have been selected and explored in some of their variants. These are the use of a smartphone camera together with a microfluidic paper platform to perform colorimetric or fluorometric assays, the use of the portable glucose meter as transducer for a variety of (bio)assays different of glucose, or the coupling of sensor arrays with advanced chemometric processing for smart sensing (electronic noses and electronic tongues)