A molecular probe for the optical detection of biogenic amines

A novel self-assembled platform for the ratiometric fluorescence detection of spermine

A novel self-assembled platform where the micelles of a pyrene derivative act as the shell and squaraine (SQ) as the nucleus was constructed for the ratiometric near infrared (NIR) fluorescence detection of urinary spermine with high selectivity.

Hydrothermal Synthesis of Silver Vanadium Oxide (Ag0.35V2O5) Nanobelts for Sensing Amines

A simple hydrothermal method for the synthesis of Ag0.35V2O5 nanobelts with the assistance of sodium dodecyl sulfate (SDS) is reported in this study. The experimental variables that may affect the nanoparticle structures were investigated. And several advanced techniques, such as TEM, HRTEM, X-ray diffraction (XRD), were used to characterize the morphology and composition of the as-prepared nanobelts. The mechanism of the formation and growth of Ag0.35V2O5 nanobelts was also investigated and discussed. The results show that SDS, as a weak reducing agent, plays a crucial role in the formation of Ag0.35V2O5. According to N2 sorption isothermals, the as-prepared Ag0.35V2O5 nanobelts are found to exhibit relative high surface area. The gas sensing performance of the Ag0.35V2O5 nanobelts towards organic amine was tested. It is found that the nanobelts show superior sensitivity of amine(s) to V2O5 particles, lower detection limit (5 ppm), and higher selectivity of amine versus ammonia at an optimized working temperature of ~260 °C. Moreover, the density functional theory (DFT) simulation was conducted to better understand the sensing mechanism. These findings may be useful in designing promising materials to detect amine gases for medical or food industrial applications.

Spermine detection via metal-mediated ethynylarene 'turn-on' fluorescence signaling

A dicarboxylated ethynylarene was shown to behave as a fluorescent chemosensor for millimolar concentrations of polyamines when mixed with Cd(II), Pb(II) or Zn(II) ions at micromolar concentrations. A bathochromic shift and intensification of fluorescence emission was observed with increasing amounts of metal ion in the presence of aqueous polyamines buffered at pH = 7.6. Such perturbations manifested as 'turn-on' signals from a ratiometric comparison of emission intensities at 390 nm versus 340 nm. Using Pb(II) as the metal mediator, spermine was selectively detected as a 40-fold signal enhancement relative to spermidine, putrescine, cadaverine and several other non-biogenic diamines. Evaluation of additional triamine and tetraamine analytes showed the influence that amine group quantity and spacing had on signal generation. By increasing the ratio of Pb(II) relative to ethynylarene, the detection limit for spermine was successfully lowered to a 25 micromolar level. Noncovalent association between ethynylarene, metal ion and polyamine are believed to promote the observed spectroscopic changes. This study exploits the subtle impact that polyamine structural identity has on transition metal chelation to define a new approach towards polyamine chemosensor development.

Amine oxidase-based biosensors for spermine and spermidine determination

The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700 mV for graphite (GP) or -100 mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3 mM for Spm and 0.01-0.4 mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5 mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.

Selective chemosensing of spermidine based on fluorescent organic nanoparticles in aqueous media via a Fe3+ displacement assay

An organic–inorganic nanohybrid complex of a tripodal complex was used for the selective determination of spermidine and its use in real sample analysis.

A novel, colorimetric method for biogenic amine detection based on arylalkylamine N-acetyltransferase

We developed a novel colorimetric method for rapid detection of biogenic amines based on arylalkylamine N-acetyltransferase (aaNAT).

Solid state organic amine detection in a photochromic porous metal organic framework

A new Mg(ii) based porous metal–organic framework (MOF) has been synthesized from naphthalenediimide (NDI) chromophoric unit containing linker. This MOF (Mg–NDI) shows instant and reversible photochromism as well as solvatochromic behavior. Due to the presence of electron deficient NDI moiety, this MOF exhibits selective organic amine (electron rich) sensing in solid state.

A new Mg(ii) based photochromic porous metal–organic framework (MOF) has been synthesized bearing naphthalenediimide (NDI) chromophoric unit. This MOF (Mg–NDI) shows instant and reversible solvatochromic behavior in presence of solvents with different polarity. Mg–NDI also exhibits fast and reversible photochromism via radical formation. Due to the presence of electron deficient NDI moiety, this MOF exhibits selective organic amine (electron rich) sensing in solid state. The organic amine detection has been confirmed by photoluminescence quenching experiment and visual color change.

Design and syntheses of novel fluorescent organosilicon-based chemosensors through click silylation: detection of biogenic amines

First report on the use of organosilicon-based chemosensors for the recognition of biogenic amines.

Fluorescence sensing of spermine with a frustrated amphiphile

A charge-frustrated amphiphile composed of a pyrene-1,3,6-trisulfonate head group and an eicosane side chain can be used as a fluorescence chemosensor for spermine. The sensor allows the detection of spermine down to the nanomolar concentration range with good selectivity over closely related biogenic amines such as spermidine.