In emergency medicine, blood lactate levels are commonly measured to assess the severity and response to treatment of hypoperfusion‐related diseases (e.g., sepsis, trauma, cardiac arrest). Clinical blood lactate testing is conducted with laboratory analyzers, leading to a delay of 3 h between triage and lactate result. Here, a fluorescence‐based blood lactate assay, which can be utilized for bedside testing, based on measuring the hydrogen peroxide generated by the enzymatic oxidation of lactate is described. To establish a hydrogen peroxide assay, near‐infrared cyanine derivatives are screened and sulfo‐cyanine 7 is identified as a new horseradish peroxidase (HRP) substrate, which loses its fluorescence in presence of HRP and hydrogen peroxide. As hydrogen peroxide is rapidly cleared by erythrocytic catalase and glutathione peroxidase, sulfo‐cyanine 7, HRP, and lactate oxidase are encapsulated in a liposomal reaction compartment. In lactate‐spiked bovine whole blood, the newly developed lactate assay exhibits a linear response in a clinically relevant range after 10 min. Substituting lactate oxidase with glucose and alcohol oxidase allows for blood glucose, ethanol, and methanol biosensing, respectively. This easy‐to‐use, rapid, and versatile assay may be useful for the quantification of a variety of enzymatically oxidizable metabolites, drugs, and toxic substances in blood and potentially other biological fluids.
Impaired glucose metabolism in diabetes causes severe acute and long‐term complications, making real‐time detection of blood glucose indispensable for diabetic patients. Existing continuous glucose monitoring systems are unsuitable for long‐term clinical glycemic management due to poor long‐term stability. Polymer dot (Pdot) glucose transducers are implantable optical nanosensors that exhibit excellent brightness, sensitivity, selectivity, and biocompatibility. Here, it is shown that hydrogen peroxide—a product of glucose oxidation in Pdot glucose sensors—degrades sensor performance via photobleaching, reduces glucose oxidase activity, and generates cytotoxicity. By adding catalase to a glucose oxidase‐based Pdot sensor to create an enzymatic cascade, the hydrogen peroxide product of glucose oxidation is rapidly decomposed by catalase, preventing its accumulation and improving the sensor's photostability, enzymatic activity, and biocompatibility. Thus, a next‐generation Pdot glucose transducer with a multienzyme reaction system (Pdot–GOx/CAT) that provides excellent sensing characteristics as well as greater detection system stability is presented. Pdot glucose transducers that incorporate this enzymatic cascade to eliminate hydrogen peroxide will possess greater long‐term stability for improved continuous glucose monitoring in diabetic patients.
more » « less- PAR ID:
- 10453744
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Healthcare Materials
- Volume:
- 10
- Issue:
- 4
- ISSN:
- 2192-2640
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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