Spermine
and spermidine serve as the key biomarkers for early-stage
cancer diagnosis. This work reports a rapid, highly selective, and
noninvasive sensing platform for spermine/spermidine. The hybrid material,
developed in this work, has been characterized by UV–vis, IR,
powder XRD, SEM, EDX, and rheological studies. Storage modulus (G′) and loss modulus (G″)
measurements infer that embedding boronic acid integrated coumarin
softens the agarose gel fibers at room temperature. Stress resistance
measurement and subsequent imaging further confirms the softness of
the hybrid hydrogel over pure agarose gel and homogeneous distribution
of the dye in the hybrid matrix as well. The soft hydrogel with a
limit-of-detection (LOD) value of 6 μM showed a nearly 27-fold
fluorescence enhancement for spermine. The hybrid hydrogel matrix
can be useful within a wide concentration window (6 μM–2.5
mM spermine). Response time (≤7 s) confirms rapid detection
ability of the material. Noninterference from various metal ions,
common anions, monosaccharides, nucleobases, and amino acids, particularly,
histidine, arginine, lysine, ornithine, glutamine, etc., makes
the hybrid hydrogel suitable for the real-time measurement of spermine
in human urinary and blood samples. Furthermore, noninterference from
other biogenic amines supports the highly selective nature of the
hybrid gel. The ability to measure spermine in urinary samples by
the probe offers a noninvasive nature of the sensing platform. Overall,
we envisioned that the hybrid material formulation would be useful
for diagnosing early-stage tumors and assessing the recovery of patients
undergoing chemotherapeutic treatment.
A series of intramolecularly hydrogen-bonded zwitterionic compartmental ligands HL1-HL4, containing a pendent diamine arm that is monoprotonated and an aldehyde functionality at two different ortho-positions of a 4-halophenoxide, is reported herein. Single-crystal X-ray diffraction (SXRD) provides persuasive evidence for the identification of this class of proton-transferred zwitterions at room temperature. The solid-state photoluminescent nature of these zwitterions remains intact in aqueous and organic solutions. Grinding of HL1 and HL2 with Cu /Ni salts develop turn-on probes 1-4. Compounds 1 and 4 are dinuclear Cu and Ni species, respectively. Compound 2 is a tetranuclear Cu complex. Interestingly, compound 3 is a mononuclear Ni species in which both nitrogen atoms in the pendant diamine arm are protonated and, therefore, not coordinated to the Ni center. All these probes (1-4) display an instant response to the poison gas hydrogen cyanide (HCN) and cyanide salts present in both solid matrices and aqueous (100 % water) solution. Selective and rapid sensing of HCN gas and cyanide salts in solid/soil/water phases, without any interference, by the mechanosynthesized complexes 1-4 can be perceived easily by the naked eye under a hand-held UV lamp.
A Cu(2+)-specific colorimetric reversible fluorescent receptor was designed and synthesized which showed a naked eye observable colour change from colourless to pink on addition of an aqueous buffer (pH 7.4) solution of 30 ppb Cu(2+). Short response time (≤5 s) and low detection limit (nearly 3 ppb) make suitable as a reliable "dip-in" open eye sensor for Cu(2+). Bio-imaging application in live brine shrimp Artemia enabled to detect Cu(2+) at as low as 10 ppb exposure.
In this work, we describe a series of water soluble copper(ii) compounds capable of selectively measuring the cardiac marker homocysteine in patients’ blood plasma via fluorescence technique.
Picomolar level nonchemodosimetric probing of bisulfate in pure aqueous buffer at neutral pH by mechanosynthesized zwitterions and their unprecedented application in the estimation of bisulfate in edible plant foods, drugs, and urine samples.
A Cu(II)-selective electrode has
been fabricated by utilizing a
mechanochemically synthesized copper-specific ionophore “L”
embedded in a poly(vinyl chloride) membrane. 2-Nitrophenyloctylether
and sodium tetraphenylborate have been used as a plasticizer and as
a solvent mediator, respectively, and found to be enhancing the sensitivity
of the fabricated ion-selective electrode (ISE). A range of membranes
(S1–S7) with varying compositions were casted and investigated
in ISE. Results revealed an excellent Nernstian response of 29.38
± 0.55 mV/dec for the ISE S6. The fabricated ISE operates well
in the pH window 4.0–7.5, and the limit of detection was found
to be 5 μM (0.3 ppm). Quick response time (15 s), long shelf-life,
and selectivity (on the order of 10
–4
and 10
–5
) over a number of interfering cations enabled S6
promising for real off laboratory sample analysis and can be employed
to detect copper ion in various industrial as well as biological and
environmental samples. To demonstrate the practical application of
these ISE, the Cu concentration in the digested printed circuit board
has been estimated using the standard calibration plot. The fabricated
ISE has been regenerated through extracting copper by chelating with
ethylenediaminetetraacetic acid.
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