A New Cross-Linkable Oxygen Sensor Covalently Bonded into Poly(2-hydroxyethyl methacrylate)-co-Polyacrylamide Thin Film for Dissolved Oxygen Sensing

Abstract

A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors' photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking characteristics can be widely applied to generate many interesting oxygen sensing materials for studying biological phenomena.

Poly(ε-caprolactone)-containing graft copolymers for ratiometric extracellular oxygen sensing

“…1, 8.2, 12.3, 16.4, 20.5, 24.6, 28.7, 32.8, 36.9, and 41.0 mg/L respectively. 84 s, respectively [62]. This comparison demonstrated that these micelles are reasonable materials for oxygen sensing.…”

“…5A), respectively. Recovery times from the air saturated solution to deoxygenated solution were slower with a t 90-r of 100 s and t 95-r of 132 s. These response times were quite faster than those of PtTFPP physically doped in poly(2-hydroxyethyl methacrylate) (PHEMA) matrix and faster than those of PtTFPP physically doped in polystyrene (PS) matrix [62]. The t 95 of PtTFPP in PHEMA and PS matrices from deoxygenated solutions to oxygenated solutions are 50 and 4.…”

Wearable Flexible Sensors: A Review

“…Carbon monoxide (CO) and carbon dioxide (CO 2 ) [139] gas sensors were fitted in the garments or boots of the people like firefighters for safe measures. Oxygen (O 2 ) sensing systems [140,141] were designed and mounted on the wrist of a person to determine the continuous change in oxygen level is happening in hemoglobin during respiration. Microelectromechanical systems (MEMS) fabrication techniques have been primarily involved to fabrication WFS for biological applications.…”

Hydrogels for the Application of Articular Cartilage Tissue Engineering: A Review of Hydrogels

“…Glucose-sensing hydrogel materials are candidates that would be used as a glucose monitoring system for diabetic patients [136,137]. Researchers have found a suitable category of such material, known as "bio-smart" material, which combines the arti cial molecular identi cation with actuation and contains poly (methyl acrylate) and (hydroxyethyl) methacrylate [138,139]. To use functional hydrogel in diabetic study, when the glucose oxidation enzyme in the presence of oxygen transforms blood sugar to gluconic acid, the local pH value of the bulk medium decreases, where change rises the swelling property of positively charged hydrogels and thus discharges the insulin.…”