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Hasan H, Kumar V, Ge X, Sundberg C, Slaughter C, Rao G. An automatic glucose monitoring system based on periplasmic binding proteins for online bioprocess monitoring. Biosens Bioelectron 2024; 253:116138. [PMID: 38428070 DOI: 10.1016/j.bios.2024.116138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/08/2024] [Accepted: 02/17/2024] [Indexed: 03/03/2024]
Abstract
Glucose is one of the most vital nutrients in all living organisms, so its monitoring is critical in healthcare and bioprocessing. Enzymatic sensors are more popular as a technology solution to meet the requirement. However, periplasmic binding proteins have been investigated extensively for their high sensitivity, enabling microdialysis sampling to replace existing complex and expensive glucose monitoring solutions based on enzymatic sensors. The binding proteins are used as optical biosensors by introducing an environment-sensitive fluorophore to the protein. The biosensor's construction, characterization, and potential application are well studied, but a complete glucose monitoring system based on it is yet to be reported. This work documents the development of the first glucose sensor prototype based on glucose binding protein (GBP) for automatic and continuous glucose measurements. The development includes immobilizing the protein into reusable chips and a low-cost solution for non-invasive glucose sampling in bioprocesses using microdialysis sampling technique. A program was written in LabVIEW to accompany the prototype for the complete automation of measurement. The sampling technique allowed glucose measurements of a few micromolar to 260 mM glucose levels. A thorough analysis of the sampling mode and the device's performance was conducted. The reported measurement accuracy was 81.78%, with an RSD of 1.83%. The prototype was also used in online glucose monitoring of E. coli cell culture. The mode of glucose sensing can be expanded to the measurement of other analytes by switching the binding proteins.
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Affiliation(s)
- Hasibul Hasan
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Vikash Kumar
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Xudong Ge
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Chad Sundberg
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Christopher Slaughter
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Govind Rao
- Center for Advanced Sensor Technology (CAST), University of Maryland, Baltimore County, Baltimore, MD, USA; Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA.
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Pang Z, Sokolov M, Kubař T, Elstner M. Unravelling the mechanism of glucose binding in a protein-based fluorescence probe: molecular dynamics simulation with a tailor-made charge model. Phys Chem Chem Phys 2022; 24:2441-2453. [PMID: 35019922 DOI: 10.1039/d1cp03733a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fluorophores linked to the glucose/galactose-binding protein (GGBP) are a promising class of glucose sensors with potential application in medical devices for diabetes patients. Several different fluorophores at different positions in the protein were tested experimentally so far, but a deeper molecular understanding of their function is still missing. In this work, we use molecular dynamics simulations to investigate the mechanism of glucose binding in the GGBP-Badan triple mutant and make a comparison to the GGBP wild-type protein. The aim is to achieve a detailed molecular understanding of changes in the glucose binding site due to the mutations and their effect on glucose binding. Free simulations give an insight into the changes of the hydrogen-bonding network in the active site and into the mechanisms of glucose binding. Additionally, metadynamics simulations for wild type and mutant unravel the energetics of binding/unbinding in these proteins. Computed free energies for the opening of the binding pocket for the wild-type and the mutant agree well with the experimental data. Further, the simulations also give an insight into the changes of the chromophore conformations upon glucose binding, which can help to understand fluorescence changes. Therefore, the molecular details unravelled in this work may support effective optimisation strategies for the construction of more efficient glucose sensors.
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Affiliation(s)
- Ziwei Pang
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Monja Sokolov
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Tomáš Kubař
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany. .,Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
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3
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Brown S, Zambrana PN, Ge X, Bagdure D, Stinchcomb AL, Rao G, Tolosa L. Minimally invasive technique for measuring transdermal glucose with a fluorescent biosensor. Anal Bioanal Chem 2018; 410:7249-7260. [PMID: 30171282 DOI: 10.1007/s00216-018-1336-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/15/2018] [Accepted: 08/17/2018] [Indexed: 11/24/2022]
Abstract
There is a need for blood glucose monitoring techniques that eliminate the painful and invasive nature of current methods, while maintaining the reliability and accuracy of established medical technology. This research aims to ultimately address these shortcomings in critically ill pediatric patients. Presented in this work is an alternative, minimally invasive technique that uses microneedles (MN) for the collection of transdermal glucose (TG). Due to their comparable skin properties, diffusion studies were performed on full thickness Yucatan miniature pig skin mounted to an in-line diffusion flow cell and on different skin sites of human subjects. Collected TG samples were measured with a L255C mutant of the E. coli glucose-binding protein (GBP) with an attached fluorescent probe. The binding constant (Kd = 0.67 μM) revealed the micromolar sensitivity and high selectivity of the his-tagged GBP biosensor for glucose, making it suitable for TG measurements. In both the animal and human models, skin permeability and TG diffusion across the skin increased with MN application. For intact and MN-treated human skin, a significant positive linear correlation (r > 0.95, p < 0.01) existed between TG and BG. The micromolar sensitivity of GBP minimized the volume required for interstitial fluid glucose analysis allowing MN application time (30 s) to be shortened compared to other studies. This time reduction can help in eliminating skin irritation issues and improving practical use of the technique by caregivers in the hospital. In addition, the his-tagged optical biosensor used in this work can be immobilized and used with a portable sensing fluorometer device at the point of care (POC) making this minimally invasive technology more ideal for use in the pediatric intensive care unit. Graphical abstract ᅟ.
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Affiliation(s)
- Sheniqua Brown
- Center for Advanced Sensor Technology Research (CAST), Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Paige N Zambrana
- Department of Pharmaceutical Sciences, University of Maryland, 20 North Pine Street, Baltimore, MD, 21201, USA
| | - Xudong Ge
- Center for Advanced Sensor Technology Research (CAST), Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Dayanand Bagdure
- Department of Pediatrics, University of Maryland Medical Center, 110 S Paca Street, Baltimore, MD, 21201, USA
| | - Audra L Stinchcomb
- Department of Pharmaceutical Sciences, University of Maryland, 20 North Pine Street, Baltimore, MD, 21201, USA
| | - Govind Rao
- Center for Advanced Sensor Technology Research (CAST), Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Leah Tolosa
- Center for Advanced Sensor Technology Research (CAST), Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
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Fonin AV, Golikova AD, Zvereva IA, D'Auria S, Staiano M, Uversky VN, Kuznetsova IM, Turoverov KK. Osmolyte-Like Stabilizing Effects of Low GdnHCl Concentrations on d-Glucose/d-Galactose-Binding Protein. Int J Mol Sci 2017; 18:E2008. [PMID: 28925982 PMCID: PMC5618657 DOI: 10.3390/ijms18092008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/14/2017] [Accepted: 09/16/2017] [Indexed: 11/16/2022] Open
Abstract
The ability of d-glucose/d-galactose-binding protein (GGBP) to reversibly interact with its ligands, glucose and galactose, makes this protein an attractive candidate for sensing elements of glucose biosensors. This potential is largely responsible for attracting researchers to study the conformational properties of this protein. Previously, we showed that an increase in the fluorescence intensity of the fluorescent dye 6-bromoacetyl-2-dimetylaminonaphtalene (BADAN) is linked to the holo-form of the GGBP/H152C mutant in solutions containing sub-denaturing concentrations of guanidine hydrochloride (GdnHCl). It was hypothesized that low GdnHCl concentrations might lead to compaction of the protein, thereby facilitating ligand binding. In this work, we utilize BADAN fluorescence spectroscopy, intrinsic protein UV fluorescence spectroscopy, and isothermal titration calorimetry (ITC) to show that the sub-denaturing GdnHCl concentrations possess osmolyte-like stabilizing effects on the structural dynamics, conformational stability, and functional activity of GGBP/H152C and the wild type of this protein (wtGGBP). Our data are consistent with the model where low GdnHCl concentrations promote a shift in the dynamic distribution of the protein molecules toward a conformational ensemble enriched in molecules with a tighter structure and a more closed conformation. This promotes the increase in the configurational complementarity between the protein and glucose molecules that leads to the increase in glucose affinity in both GGBP/H152C and wtGGBP.
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Affiliation(s)
- Alexander V Fonin
- Institute of Cytology of the Russian Academy of Sciences, Laboratory of Structural Dynamics, Stability and Folding of Proteins, Tikhoretsky av. 4, 194064 St. Petersburg, Russia.
| | - Alexandra D Golikova
- Saint Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia.
| | - Irina A Zvereva
- Saint Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia.
| | - Sabato D'Auria
- CNR, Institute of Food Science, via Roma 64, 83100 Avellino, Italy.
| | - Maria Staiano
- CNR, Institute of Food Science, via Roma 64, 83100 Avellino, Italy.
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
| | - Irina M Kuznetsova
- Institute of Cytology of the Russian Academy of Sciences, Laboratory of Structural Dynamics, Stability and Folding of Proteins, Tikhoretsky av. 4, 194064 St. Petersburg, Russia.
| | - Konstantin K Turoverov
- Institute of Cytology of the Russian Academy of Sciences, Laboratory of Structural Dynamics, Stability and Folding of Proteins, Tikhoretsky av. 4, 194064 St. Petersburg, Russia.
- Department of Biophysics, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya av. 29, 195251 St. Petersburg, Russia.
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El-Sayed MMH, Brown SR, Mupparapu K, Tolosa L. The effect of pH on the glucose response of the glucose-galactose binding protein L255C labeled with Acrylodan. Int J Biol Macromol 2016; 86:282-7. [PMID: 26812111 DOI: 10.1016/j.ijbiomac.2016.01.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 11/16/2022]
Abstract
The glucose-galactose binding protein (GGBP) is used as an optical biosensor in medical and bioprocess applications. This paper investigates the effect of pH on the behavior of GGBP-L255C labeled with Acrylodan for the purpose of finding the optimum conditions for sensing purposes as well as for protein preparation, purification and storage. The Acrylodan-GGBP fluorescence response in absence and presence of glucose was measured under varying buffer and pH conditions. Dissociation constants (Kd) and Gibbs free energies (ΔG) for the protein-glucose binding were calculated. Binding was found to be energetically favored at slightly acidic to neutral conditions, specifically close to the pI of GBP (∼ 5.0). Minimal fluorescence response to glucose was exhibited at pH 3.0 accompanied by a blue shift in the steady state fluorescence spectrum. In contrast, an almost 45% response to glucose was shown at pH 4.5-9.0 with a 13-nm red shift. Frequency domain lifetime measurements and quenching with KI suggest that at highly acidic conditions both the glucose-free and the glucose-bound protein are in a conformation distinct from those observed at higher pH values.
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Affiliation(s)
- Mayyada M H El-Sayed
- Center for Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
| | - Sheniqua R Brown
- Center for Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
| | - KarunaSri Mupparapu
- Center for Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
| | - Leah Tolosa
- Center for Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
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6
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Stepanenko OV, Fonin AV, Stepanenko OV, Staiano M, D'Auria S, Kuznetsova IM, Turoverov KK. Tryptophan residue of the D-galactose/D-glucose-binding protein from E. Coli localized in its active center does not contribute to the change in intrinsic fluorescence upon glucose binding. J Fluoresc 2014; 25:87-94. [PMID: 25501855 DOI: 10.1007/s10895-014-1483-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/25/2014] [Indexed: 11/24/2022]
Abstract
Changes of the characteristics of intrinsic tryptophan fluorescence of the wild type of D-galactose/D-glucose-binding protein from Escherichia coli (GGBPwt) induced by D-glucose binding were examined by the intrinsic UV-fluorescence of proteins, circular dyhroism in the near-UV region, and acrylamide-induced fluorescence quenching. The analysis of the different characteristics of GGBPwt and its mutant form GGBP-W183A together with the analysis of the microenvironment of tryptophan residues of GGBPwt revealed that Trp 183, which is directly involved in sugar binding, has the least influence on the provoked by D-glucose blue shift and increase in the intensity of protein intrinsic fluorescence in comparison with other tryptophan residues of GGBP.
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Affiliation(s)
- Olga V Stepanenko
- Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky ave., 4, 194064, St. Petersburg, Russia
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Fonin AV, Stepanenko OV, Povarova OI, Volova CA, Philippova EM, Bublikov GS, Kuznetsova IM, Demchenko AP, Turoverov KK. Spectral characteristics of the mutant form GGBP/H152C of D-glucose/D-galactose-binding protein labeled with fluorescent dye BADAN: influence of external factors. PeerJ 2014; 2:e275. [PMID: 24711960 PMCID: PMC3970809 DOI: 10.7717/peerj.275] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 01/26/2014] [Indexed: 11/22/2022] Open
Abstract
The mutant form GGBP/H152C of the D-glucose/D-galactose-binding protein with the solvatochromic dye BADAN linked to cysteine residue Cys 152 can be used as a potential base for a sensitive element of glucose biosensor system. We investigated the influence of various external factors on the physical-chemical properties of GGBP/H152C-BADAN and its complex with glucose. The high affinity (Kd = 8.5 µM) and high binding rate of glucose make GGBP/H152C-BADAN a good candidate to determine the sugar content in biological fluids extracted using transdermal techniques. It was shown that changes in the ionic strength and pH of solution within the physiological range did not have a significant influence on the fluorescent characteristics of GGBP/H152C-BADAN. The mutant form GGBP/H152C has relatively low resistance to denaturation action of GdnHCl and urea. This result emphasizes the need to find more stable proteins for the creation of a sensitive element for a glucose biosensor system.
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Affiliation(s)
- Alexander V Fonin
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia
| | - Olga V Stepanenko
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia
| | - Olga I Povarova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia
| | - Catherine A Volova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia ; Department of Biology, St. Petersburg State University , St. Petersburg , Russia
| | - Elizaveta M Philippova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia ; Department of Physical Electronics, St. Petersburg State Polytechnical University , St. Petersburg , Russia
| | - Grigory S Bublikov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia
| | - Irina M Kuznetsova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia ; Department of Biophysics, St. Petersburg State Polytechnical University , St. Petersburg , Russia
| | - Alexander P Demchenko
- Laboratory of Nanobiotechnologies, Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine , Kiev , Ukraine
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Science , St. Petersburg , Russia ; Department of Biophysics, St. Petersburg State Polytechnical University , St. Petersburg , Russia
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Woo HC, Tolosa L, El-Metwally D, Viscardi RM. Glucose monitoring in neonates: need for accurate and non-invasive methods. Arch Dis Child Fetal Neonatal Ed 2014; 99:F153-7. [PMID: 24065727 DOI: 10.1136/archdischild-2013-304682] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Neonatal hypoglycaemia can lead to devastating consequences. Thus, constant, accurate and safe glucose monitoring is imperative in neonatal care. However, point-of-care (POC) devices for glucose testing currently used for neonates were originally designed for adults and do not address issues specific to neonates. This review will address currently available monitoring options and describe new methodologies for non-invasive glucose monitoring in newborns.
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Affiliation(s)
- Hyung Chul Woo
- Division of Neonatology, Department of Pediatrics, School of Medicine, University of Maryland, Baltimore, , Baltimore, Maryland, USA
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Kostov Y, Ge X, Rao G, Tolosa L. Portable system for the detection of micromolar concentrations of glucose. MEASUREMENT SCIENCE & TECHNOLOGY 2014; 25:025701. [PMID: 24587594 PMCID: PMC3934490 DOI: 10.1088/0957-0233/25/2/025701] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Glucose in non-invasively collected biofluids is generally in the micromolar range and thus, requires sensing methodologies capable of measuring glucose at these levels. Here, we present a small fluorometer system that can quantify glucose in the range of 0-5 μM with resolution of ~0.07 μM. It relies on the glucose binding protein (GBP) fluorescently labeled with two fluorophores. Fluorescence signals from the dual-labeled GBP are utilized in a ratiometric mode, making the measurements insensitive to variations in protein concentration and other systematic errors. Fluorescence is quantified by a miniature, dedicated ratiometric fluorometer that is powered via USB. Concentration is calculated using an ultra-mobile personal computer (UMPC). The whole system is designed to be pocket sized suitable for point-of-care or bedside applications. Test results suggest that the system is a promising tool for accurate measurements of low glucose concentrations (0.1-10 μM) in biological samples.
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Affiliation(s)
- Yordan Kostov
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore MD, 21250
| | - Xudong Ge
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore MD, 21250
| | - Govind Rao
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore MD, 21250
| | - Leah Tolosa
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore MD, 21250
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10
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Ge X, Rao G, Kostov Y, Kanjananimmanont S, Viscardi RM, Woo H, Tolosa L. Detection of trace glucose on the surface of a semipermeable membrane using a fluorescently labeled glucose-binding protein: a promising approach to noninvasive glucose monitoring. J Diabetes Sci Technol 2013; 7:4-12. [PMID: 23439155 PMCID: PMC3692211 DOI: 10.1177/193229681300700102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Our motivation for this study was to develop a noninvasive glucose sensor for low birth weight neonates. We hypothesized that the underdeveloped skin of neonates will allow for the diffusion of glucose to the surface where it can be sampled noninvasively. On further study, we found that measurable amounts of glucose can also be collected on the skin of adults. METHOD Cellulose acetate dialysis membrane was used as surrogate for preterm neonatal skin. Glucose on the surface was collected by saline-moistened swabs and analyzed with glucose-binding protein (GBP). The saline-moistened swab was also tested in the neonatal intensive care unit. Saline was directly applied on adult skin and collected for analysis with two methods: GBP and high-performance anion-exchange chromatography (HPAEC). RESULTS The amount of glucose on the membrane surface was found (1) to accumulate with time but gradually level off, (2) to be proportional to the swab dwell time, and (3) the concentration of the glucose solution on the opposite side of the membrane. The swab, however, failed to absorb glucose on neonatal skin. On direct application of saline onto adult skin, we were able to measure by HPAEC and GBP the amount of glucose collected on the surface. Blood glucose appears to track transdermal glucose levels. CONCLUSIONS We were able to measure trace amounts of glucose on the skin surface that appear to follow blood glucose levels. The present results show modest correlation with blood glucose. Nonetheless, this method may present a noninvasive alternative to tracking glucose trends.
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Affiliation(s)
- Xudong Ge
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland
| | - Govind Rao
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland
| | - Yordan Kostov
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland
| | - Sunsanee Kanjananimmanont
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland
| | - Rose M. Viscardi
- Division of Neonatology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Hyung Woo
- Division of Neonatology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Leah Tolosa
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland
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Jin S, Veetil JV, Garrett JR, Ye K. Construction of a panel of glucose indicator proteins for continuous glucose monitoring. Biosens Bioelectron 2011; 26:3427-31. [PMID: 21333521 PMCID: PMC3074613 DOI: 10.1016/j.bios.2011.01.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 12/25/2010] [Accepted: 01/14/2011] [Indexed: 10/18/2022]
Abstract
The development of implantable glucose sensors for use in diabetes treatment has been pursued for decades. However, enzyme-based glucose sensors often fail in vivo. In our previous work, we engineered a novel glucose indicator protein (GIP) that can sense glucose without relying on any enzymes and cofactors. Nevertheless, this GIP is unsuitable for blood glucose monitoring due to its low dissociation constant. Here, we report a novel approach to creating a new GIP that can be used to monitor blood glucose level. By disrupting pi-pi stacking around GIP's glucose binding site through site-directed mutagenesis, we showed that GIP's dissociation constant can be manipulated from 0.026 mM to 7.86 mM. This approach yielded four GIP mutants. We showed that one of the mutants can be used to detect glucose from 0 to 32 mM, while another mutant can be employed to visualize intracellular glucose (0-200 μM) within living cells through FRET imaging microscopy measurement.
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Affiliation(s)
- Sha Jin
- Biomedical Engineering Program, College of Engineering, University of Arkansas, 203 Engineering Hall, Fayetteville, AR 72701, USA
| | - Jithesh V. Veetil
- Biomedical Engineering Program, College of Engineering, University of Arkansas, 203 Engineering Hall, Fayetteville, AR 72701, USA
| | - Jared R Garrett
- Biomedical Engineering Program, College of Engineering, University of Arkansas, 203 Engineering Hall, Fayetteville, AR 72701, USA
| | - Kaiming Ye
- Biomedical Engineering Program, College of Engineering, University of Arkansas, 203 Engineering Hall, Fayetteville, AR 72701, USA
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Kondragunta B, Drew JL, Brorson KA, Moreira AR, Rao G. Advances in clone selection using high-throughput bioreactors. Biotechnol Prog 2010; 26:1095-103. [DOI: 10.1002/btpr.392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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