Aggregation-Induced FRET via Polymer–Surfactant Complexation: A New Strategy for the Detection of Spermine

Abstract

A new water-soluble cationic conjugated polymer [9,9-bis(6'-methyl imidazolium bromide)hexyl)fluorene-co-4,7-(2,1,3-benzothiadiazole)] (PFBT-MI) was designed and synthesized via Suzuki cross-coupling polymerization in good yields without any tedious purification steps. PFBT-MI showed excellent photophysical responses toward SDS and SDBS with a detection limit of 0.12 μM/(34 ppb) and 0.13 μM/(45 ppb), respectively. Furthermore, occurrence of FRET from the donor (fluorene) to acceptor (BT units), via surfactant-induced aggregation, results in naked-eye detection of these common anionic surfactants (SDS/SDBS) as the color changes from blue to yellowish green in aqueous solution. The polymer-surfactant nanoaggregates thus formed via electrostatic as well as hydrophobic interactions have been explored for the sensitive detection of spermine (considered as an excellent biomarker for early cancer diagnosis) with a detection limit of 66 ppb (0.33 μM), which is much below the range 1-10 μM pertinent for the early diagnosis of cancer in urinary samples. This highly sensitive technique would facilitate the direct and noninvasive detection of spermine from urine rapidly and is likely to have great significance in early cancer diagnosis.

Design and Characterization of Dicyanovinyl Reactive Dyes for the Colorimetric Detection of Thiols and Biogenic Amines

“…Working ranges are mainly up to two decades. Wider ranges than 2 decades have the systems based on PFBT-MI and surfactant [ 6 ] and Tyrosine-protected gold nanoparticles [ 29 ]. CR-528 and CR-555 offer wider working range for the detection of NaSH than the fluorescent probe HF-PBA [ 26 ] and 4-chloro-7-nitrobenzofurazan [ 25 ] do for H 2 S. Apart from Tyrosine-protected gold nanoparticles [ 29 ], the chromoreactands provide the lowest working range for the detection of spermine and spermidine.…”

“…Biogenic amines are nitrogen-containing low molecular weight organic compounds that are naturally synthesized in animals, plants, and microorganisms—generally by decarboxylation of free amino acids or by amination or transamination of aldehydes and ketones [ 5 ]. Certain biogenic amines, like spermine and spermidine, are among the most abundant organic polycations that are found in the human body, involved in protein synthesis, conformational stabilization of nucleic acids, and cytoskeleton structures, and they play multiple roles in cell growth, proliferation, and survival [ 6 , 7 ]. Consequently, changes in levels of spermine and spermidine have been associated with aging and diseases, like cancer [ 8 ].…”

“…The aldehyde function of 4- N , N -dioctylamino-4′-formyl-2′-nitroazobenzene was found to provide significant color changes with hydrogen sulphite [ 41 ], but later also to be responsive to cysteine and homocysteine [ 42 ]. For the detection of biogenic amines in solution, Malik et al synthesized the water-soluble cationic conjugated polymer [9,9-bis(6′-methylimidazoliumbromide)hexyl)-fluorene-co-4,7-(2,1,3-benzothiadiazole)] (PFBT-MI) and combined it with a surfactant to achieve aggregates, which enabled the detection of spermine [ 6 ]. Tyrosine-protected gold nanoparticles (Tyr-Au NPs) were used by Rawat et al as a dual probe for colorimetric and fluorescence turn-on assays of spermine and spermidine in biological samples.…”

Study of the Aggregation of DNA‐Capped Gold Nanoparticles: A Smart and Flexible Aptasensor for Spermine Sensing

“…Under the optimal conditions in a blank matrix, by taking the logarithm of the absorbance ratio, a linear SPM calibration curve from 0–5 μ m could be fitted by least‐squares linear regression (Figure ). The equation was y= 0.1029×−0.4941, with the limit of detection (LOD) calculated to be 15.25 n m (3.09 ng mL −1 ) by the equation LOD=3 σ of absorbance in the absence of SPM/slope of curve . TEM images clearly showed the increase of AuNP aggregation extent in an increasing amount of SPM content (Figure ).…”

Biogenic Amines Detection by Chromatography and Sensor Methods: A Comparative Review

“…Optical sensors have been applied to determine biogenic amines in various food and beverages such as histamine, tyramine, ethylamine, putrescine, agmatine, isopentylamine, methylamine and propylamine by using speci c indicator dyes that exhibit di erent spectral characteristics when exposed to these analytes (Kumpf et al (2015); (Mastnak et al, 2018); Nedeljko et al (2017); Rawat et al (2017)). Malik et al (2016) reported the biogenic amines determination in liquid samples where this study synthesized the water-soluble cationic conjugated polymer using [9,9-bis(6'-methylimidazoliumbromide)hexyl)-uorene-co-4,7-(2,1,3-benzothiadiazole)](PFBT-MI) and combined it with a surfactant in order to acquire aggregates, which enabled the spermine detection. Rawat et al (2017) on the other hand, used tyrosine-protected gold nanoparticles (Tyr-Au-NPs) as a dual probe for colorimetric and uorescene turn-on assays of spermine and spermidine in biological samples.…”