Abstract
The hemoglobin content of blood is an important health indicator, and the presence of microscopic amounts of hemoglobin in places where it normally does not occur, e.g. in blood plasma or in urine, is a sign of diseases such as hemolytic anemia or urinary tract infections. Thus, methods to detect and quantify hemoglobin are important for clinical laboratories, blood banks, and for point-of-care diagnostics. The precipitation polymerization of N-isopropylacrylamide by hemoglobin-catalyzed atom transfer radical polymerization (ATRP) is used as an assay for hemoglobin quantification relying on the formation of turbidity as a simple optical read-out. Dose-response curves for pure hemoglobin and for hemoglobin in blood plasma, in urine, in erythrocytes, and in full blood are obtained. Turbidity formation increases with the concentration of hemoglobin. Concentrations of hemoglobin as low as 6.45 × 10-3 mg mL-1 in solution, 4.88 × 10-1 mg mL-1 in plasma, and 1.65 × 10-1 mg mL-1 in urine could be detected, which is below the clinically relevant concentrations in the respective body fluids. Total hemoglobin in full blood is also accurately determined. The reaction can be regarded as a polymerization-based signal amplification for the sensing of hemoglobin, as the analyte catalyzes the formation of radicals which add many monomer units into detectable polymer chains. While most established hemoglobin tests involve the use of highly toxic reagents such as potassium cyanide, the polymerization-based test uses simple and stable organic reagents. Thus, it is an environmentally friendlier alternative to established chemical assays for hemoglobin.
Original language | English |
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Pages (from-to) | 1162-1170 |
Number of pages | 9 |
Journal | Analytical Chemistry |
Volume | 92 |
Issue number | 1 |
Early online date | 2 Dec 2019 |
DOIs | |
Publication status | Published - 7 Jan 2020 |
Funding
The authors thank Dr. Martin Clift (Swansea University) for expertise in blood fractionation and Dr. Aziz Fennouri (Adolphe Merkle Institute) for assistance in RBC imaging. This work was supported by the Swiss National Science Foundation through projects PP00P2_144697 and PP00P2_172927, the National Centre of Competence in Research (NCCR) Bio-Inspired Materials, and a BRIDGE Proof-of-Concept grant (20B1-1_173771).
Keywords
- hemoglobin
- ATRP
- biocatalytic ATRP
- polymerization-based amplification
- anemia diagnostic
- biosensing
- precipitation polymerization