Fluorescent Nanocomposite Hydrogels Based on Conjugated Polymer Nanoparticles as Platforms for Alkaline Phosphatase Detection

Abstract

This work describes the development and characterization of fluorescent nanocomposite hydrogels, with high swelling and absorption capacity, and prepared using a green protocol. These fluorescent materials are obtained by incorporating, for the first time, polyfluorenes-based nanoparticles with different emission bands—poly[9,9-dioctylfluorenyl-2,7-diyl] (PFO) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(1,4-benzo-{2,1,3}-thiadiazole)] (F8BT)—into a three-dimensional polymeric network based on polyacrylamide. To this end, two strategies were explored: incorporation of the nanoparticles during the polymerization process (in situ) and embedment after the hydrogel formation (ex situ). The results show that the combination of PFO nanoparticles introduced by the ex situ method provided materials with good storage stability, homogeneity and reproducibility properties, allowing their preservation in the form of xerogel. The fluorescent nanocomposite hydrogels have been tested as a transportable and user-friendly sensing platform. In particular, the ability of these materials to specifically detect the enzyme alkaline phosphatase (ALP) has been evaluated as a proof-of-concept. The sensor was able to quantify the presence of the enzyme in an aqueous sample with a response time of 10 min and LOD of 21 nM. Given these results, we consider that this device shows great potential for quantifying physiological ALP levels as well as enzyme activity in environmental samples.

Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging

“…Biocompatibility is the top priority when fluorescent materials are used in bio-fields; a great number of biocompatible fluorescent materials (BFMs) have been obtained, such as organic small-molecule dyes, fluorescent conjugated polymers, metal nanoclusters, rare earth ion-based nanoparticles (e.g., rare-earth-doped upconversion nanoparticles), quantum dots, carbon nanomaterials (e.g., carbon nanotubes and carbon nanodots) and various fluorescent proteins. This Special Issue, "Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging", includes twelve research articles covering biosensors based on ion sensors, the detection of pathological oxidative stress and disease detection [1][2][3][4][5][6][7][8][9][10][11][12], as well as four review articles focused on different types of fluorescent probes and biological applications [13][14][15][16].…”

“…Prof. Xu [5] and Prof. Samanta [6] developed fluorescent probes activated by H 2 O 2 to monitor the content of H 2 O 2 in cells. Mateo's group prepared fluorescent nanocomposite hydrogels with high swelling and adsorption capacity that can quantitatively detect the presence of enzyme alkaline phosphatase (ALP) in water samples with a response time of 10 min and a LOD of 21 nm [7]. Prof. Li designed and synthesized a novel aggregation-induced fluorescent probe, PTPA-QM, which showed high affinity for beta-amyloid in brain sections of 5XFAD in mice with classical inflammatory cognitive impairment [8].…”