Effect of Active Site Modification towards Performance Enhancement in Biopolymer κ-Carrageenan Derivatives

Abstract

This research demonstrates a one-step modification process of biopolymer carrageenan active sites through functional group substitution in κ-carrageenan structures. The modification process improves the electronegative properties of κ-carrageenan derivatives, leading to enhancement of the material’s performance. Synthesized succinyl κ-carrageenan with a high degree of substitution provides more active sites for interaction with analytes. The FTIR analysis of succinyl κ-carrageenan showed the presence of new peaks at 1068 cm−1, 1218 cm−1, and 1626 cm−1 that corresponded to the vibrations of C–O and C=O from the carbonyl group. A new peak at 2.86 ppm in 1H NMR represented the methyl proton neighboring with C=O. The appearance of new peaks at 177.05 and 177.15 ppm in 13C NMR proves the substitution of the succinyl group in the κ-carrageenan structure. The elemental analysis was carried out to calculate the degree of substitution with the highest value of 1.78 at 24 h of reaction. The XRD diffractogram of derivatives exhibited a higher degree of crystallinity compared to pristine κ-carrageenan at 23.8% and 9.2%, respectively. Modification of κ-carrageenan with a succinyl group improved its interaction with ions and the conductivity of the salt solution compared to its pristine form. This work has a high potential to be applied in various applications such as sensors, drug delivery, and polymer electrolytes.

Succinyl-κ-carrageenan Silver Nanotriangles Composite for Ammonium Localized Surface Plasmon Resonance Sensor

“…This could be attributed to the extra oxygen atom in succinyl-κ-carrageenan compared to the structure of κ-carrageenan as confirmed by the FTIR in research conducted by [7]. This large difference in r a was also contributed to by the high degree of substitution during synthesis of succinyl-κ-carrageenan whereby more than one hydroxyl group in pristine κ-carrageenan was substituted with the higher oxygen atom succinyl group [7]. This research pattern was reported previously, whereby adding oxygen-containing compounds increases the surface roughness up to 15 times compared to precursor compound [4,[15][16][17].…”

“…Due to the increased electronegative active site in succinyl-κ-carrageenan, it is expected the succinyl-κ-carrageenan operates better than the pristine κ-carrageenan LSPR sensor. The succinyl-κ-carrageenan was established in a report by Bakar et al [7]; thus, molecular characterization is not reported in this work. This research focuses on studying the physicochemical properties of succinylκ-carrageenan and evaluating its performance as a potential active material for the NH 4 + LSPR sensor.…”

“…Succinyl-κ-carrageenan was synthesised according to the previous technique established in [7]. One gram of κ-carrageenan was dissolved in 200 mL of distilled water and transferred into the conical flask.…”

“…Recently, κ-carrageenan has been extensively used in research due to the high number of active sites such as hydroxyl and sulphate groups. κ-carrageenan has been studied for heavy metal adsorbent in LSPR sensors, mercury ion colorimetric detectors, and as a host in polymer electrolyte application [7]. Because of the existence of extra oxygen atoms provided by hydroxyl (O-H) and sulfate (O=S=O) groups in the κ-carrageenan structure, the sensor performance of LSPR is better when utilising κ-carrageenan as a sensing material in comparison to chitosan [3].…”

“…Bakar et al successfully synthesized succinyl-κ-carrageenan by reacting succinic anhydride with κ-carrageenan in a one-step reaction method [7]. It was reported that succinyl-κ-carrageenan increased the performance of the polysaccharide.…”