A fluorescent glucose sensor binding covalently to all five hydroxy groups of α-D-glucofuranose. A reinvestigation

Fluorescence sensors for monosaccharides based on the 6-methylquinolinium nucleus and boronic acid moiety: potential application to ophthalmic diagnostics

“…Naturally, boronic acid compounds have been considered as a chelating group for the synthesis of glucose sensors [ 32 -39 ], where we note the work of Shinkai [ 32 , 33 ], Norrild [ 34 ], Lakowicz [ 35 -39 ] and Drueckhammer [ 25 ]. However, the published probes developed for solution (blood/serum)-based measurements are not compatible for glucose sensing within a contact lens, because of the different microenvironment within the lens, in particular, the local pH and polarity [ 17 ].…”

Wavelength–Ratiometric Probes for the Selective Detection of Fluoride Based on the 6-Aminoquinolinium Nucleus and Boronic Acid Moiety

“…The affinity of boronic acid for diols is well known [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], hence for any fluoride sensor based on the boronic acid moiety, it is important to characterize the monosaccharide response. Subsequently, we tested the response of BAQBAs towards both glucose and fructose.…”

“…Since the boronic acid group also interacts with other strong bases such as hydroxyl ions [37], BAQBAs are likely to also have a pH dependent response, although at pH 7 such as in physiological fluids or waste waters, the interaction is low (the concentration of OH − = 10 −7 M) and environmental and physiological safeguard sensing applications do not experience notable pH changes. While the many boronic acid containing fluorophores that have been synthesized to date [21][22][23][24][25][26][27] and are likely to show a fluoride response, only a few will demonstrate spectral shifts and intensity changes, affording for ratiometric sensing, while even fewer will demonstrate an additional poor/non-sugar response. Further, BAQBAs offer the additional possibility of lifetime based halide sensing (collisional quenching).…”

“…In contrast, a greater electron deficient nitrogen center provides for a higher affinity for monosaccharides (data not shown) [36]. Hence our unique choice of backbone substituents affords a high fluoride affinity with relatively little sugar response, even in the case of fructose, which is wellknown to have a high boronic acid affinity [21][22][23][24][25][26][27]. In this paper we characterize the fluoride response of BAQBAs in the presence of potential interferences such as sugar and other halides and, also the response towards the halides.…”

“…Fluoride can be accurately determined using fluoride-ion selective electrodes [8], spectrophotometry [9], gas chromatography [10] and even colorimetrically using boronic acid chemistry [11,12], although such systems are poisoned by the presence of sugars such as by glucose or fructose. It is due to the well-known high affinity between diol containing compounds and the boronic acid moiety that has lead to the development of carbohydrate sensors [13][14][15][16][17][18][19] chromatographic materials [20] and many glucose sensors [21][22][23][24][25][26][27].…”