Long term response of a Concanavalin-A based fluorescence glucose sensing assay

Locke, Andrea K.; Cummins, Brian M.; Abraham, Alexander A.; Coté, Gerard L.

doi:10.1117/12.2080327

Cited by 2 publications

(4 citation statements)

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“…ConA is of value to continuous glucose biosensing because it can reversibly bind to mannose and glucose molecules without altering the protein’s covalent structures [ 21 ]. In addition, ConA has a high specificity to glucose and a ConA-based assay has demonstrated good specificity to glucose in the presence of galactose, fructose, lactose, and sorbitol [ 22 , 23 , 24 , 25 ]. Toxicology studies of ConA have previously been analyzed for the application of a minimally invasive glucose biosensor where the protein would be housed in a semipermeable membrane and showed an extremely low risk within the concentrations of interest [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

A Polarity-Sensitive Far-Red Fluorescent Probe for Glucose Sensing through Skin

Colvin

Dunlap

et al. 2023

Biosensors

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The field of glucose biosensors for diabetes management has been of great interest over the past 60 years. Continuous glucose monitoring (CGM) is important to continuously track the glucose level to provide better management of the disease. Concanavalin A (ConA) can reversibly bind to glucose and mannose molecules and form a glucose biosensor via competitive binding. Here, we developed a glucose biosensor using ConA and a fluorescent probe, which generated a fluorescent intensity change based on solvatochromism, the reversible change in the emission spectrum dependent on the polarity of the solvent. The direction in which the wavelength shifts as the solvent polarity increases can be defined as positive (red-shift), negative (blue-shift), or a combination of the two, referred to as reverse. To translate this biosensor to a subcutaneously implanted format, Cyanine 5.5 (Cy5.5)-labeled small mannose molecules were used, which allows for the far-red excitation wavelength range to increase the skin penetration depth of the light source and returned emission. Three Cy5.5-labeled small mannose molecules were synthesized and compared when used as the competing ligand in the competitive binding biosensor. We explored the polarity-sensitive nature of the competing ligands and examined the biosensor’s glucose response. Cy5.5-mannotetraose performed best as a biosensor, allowing for the detection of glucose from 25 to 400 mg/dL. Thus, this assay is responsive to glucose within the physiologic range when its concentration is increased to levels needed for an implantable design. The biosensor response is not statistically different when placed under different skin pigmentations when comparing the percent increase in fluorescence intensity. This shows the ability of the biosensor to produce a repeatable signal across the physiologic range for subcutaneous glucose monitoring under various skin tones.

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Section: Introductionmentioning

confidence: 99%

A Polarity-Sensitive Far-Red Fluorescent Probe for Glucose Sensing through Skin

Colvin

Dunlap

et al. 2023

Biosensors

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confidence: 99%

“…Therefore, the specificity of this modified ConA based assay was addressed in previous work, which showed the fluorescence anisotropy response of the assay in the presence of varying concentrations of D-glucose, Dgalactose, and methyl-α-D-mannopyranoside. 22 Herein, we introduce a new type of fluorescently labeled competing ligand for use in FRET-based glucose sensing assays. This ligand is rationally designed to present a single binding epitope (core trimannose) in close proximity to the signaling fluorophore.…”

mentioning

confidence: 99%

“…We have recently shown that the long-term stability of the assay can be maintained by tethering ConA to PEG chains (i.e., PEGylating ConA) and introduced a new type of competing ligand that achieves the desirable affinity while preventing aggregation with free ConA in free solution. , Also, ConA is known to bind to both glucose and mannose residues with different binding affinities. Therefore, the specificity of this modified ConA based assay was addressed in previous work, which showed the fluorescence anisotropy response of the assay in the presence of varying concentrations of d -glucose, d -galactose, and methyl-α- d -mannopyranoside …”

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confidence: 99%

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High Affinity Mannotetraose as an Alternative to Dextran in ConA Based Fluorescent Affinity Glucose Assay Due to Improved FRET Efficiency

Locke¹,

Cummins

Coté³

2016

ACS Sens.

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Diabetes mellitus affects millions of people worldwide and requires that individuals tightly self-regulate their blood glucose levels to minimize the associated secondary complications. Continuous monitoring devices potentially offer patients a long-term means to tightly monitor their glucose levels. In recent years, fluorescent affinity sensors based on lectins (e.g., Concanavalin A (ConA)) have been implemented in such devices. Traditionally, these sensors pair the lectin with a multivalent ligand, like dextran, in order to develop a competitive binding assay that changes its fluorescent properties in response to the surrounding glucose concentrations. This work introduces a new type of fluorescent ligand for FRET-based assays in an attempt to improve the sensitivity of such assays. This ligand is rationally designed to present a core trimannose structure and a donor fluorophore in close proximity to one another. This design decreases the distance between the FRET donor and the FRET acceptors on ConA to maximize the FRET efficiency upon binding of the ligand to ConA. This work specifically compares the FRET efficiency and sensitivity of this new competing ligand with a traditional dextran ligand, showing that the new ligand has improved characteristics. This work also tested the long-term thermal stability of the assay based on this new competing ligand and displayed a MARD of less than 10% across the physiological range of glucose after 30 days incubation at 37 °C. Ultimately, this new type of fluorescent ligand has the potential to significantly improve the accuracy of continuous glucose monitoring devices based on the competitive binding sensing approach.

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Long term response of a Concanavalin-A based fluorescence glucose sensing assay

Cited by 2 publications

References 10 publications

A Polarity-Sensitive Far-Red Fluorescent Probe for Glucose Sensing through Skin

A Polarity-Sensitive Far-Red Fluorescent Probe for Glucose Sensing through Skin

High Affinity Mannotetraose as an Alternative to Dextran in ConA Based Fluorescent Affinity Glucose Assay Due to Improved FRET Efficiency

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