Crosslinking of phenylboronic acid receptors as a means of glucose selective holographic detection

A holographic sensor for the detection of glucose has been developed that is based on a hydrogel film containing phenylboronic acid receptors. Changes to the replay wavelength of the hologram were used to characterise the swelling and de-swelling behaviour of the hydrogel matrix upon receptor-ligand binding. The effect of introducing a fixed positive charge into the polymer matrix by modification of the hydrogel with a quaternary amine group (3-acrylamidopropyl)trimethylammonium chloride (ATMA), was investigated for a range of sugars and the alpha-hydroxy acid, lactate, at physiological pH. The quaternary amine-modified hydrogel matrix was found to contract in the presence of glucose, whereas, it was minimally responsive to other saccharides. The selectivity of the sensor for glucose compared to lactate was also significantly improved compared to the unmodified film. A crosslinking mechanism is proposed to explain the enhanced selectivity to glucose.