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Linn JD, Liberman L, Neal CAP, Calabrese MA. Role of chain architecture in the solution phase assembly and thermoreversibility of aqueous PNIPAM/silyl methacrylate copolymers. Polym Chem 2022; 13:3840-3855. [PMID: 37193094 PMCID: PMC10181847 DOI: 10.1039/d2py00254j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stimuli-responsive polymers functionalized with reactive inorganic groups enable creation of macromolecular structures such as hydrogels, micelles, and coatings that demonstrate smart behavior. Prior studies using poly(N-isopropyl acrylamide-co-3-(trimethoxysilyl)propyl methacrylate) (P(NIPAM-co-TMA)) have stabilized micelles and produced functional nanoscale coatings; however, such systems show limited responsiveness over multiple thermal cycles. Here, polymer architecture and TMA content are connected to the aqueous self-assembly, optical response, and thermo-reversibility of two distinct types of PNIPAM/TMA copolymers: random P(NIPAM-co-TMA), and a 'blocky-functionalized' copolymer where TMA is localized to one portion of the chain, P(NIPAM-b-NIPAM-co-TMA). Aqueous solution behavior characterized via cloud point testing (CPT), dynamic light scattering (DLS), and variable-temperature nuclear magnetic resonance spectroscopy (NMR) demonstrates that thermoresponsiveness and thermoreversibility over multiple cycles is a strong function of polymer configuration and TMA content. Despite low TMA content (≤2% mol), blocky-functionalized copolymers assemble into small, well-ordered structures above the cloud point that lead to distinct transmittance behaviors and stimuli-responsiveness over multiple cycles. Conversely, random copolymers form disordered aggregates at elevated temperatures, and only exhibit thermoreversibility at negligible TMA fractions (0.5% mol); higher TMA content leads to irreversible structure formation. This understanding of the architectural and assembly effects on the thermal cyclability of aqueous PNIPAM-co-TMA can be used to improve the scalability of responsive polymer applications requiring thermoreversible behavior, including sensing, separations, and functional coatings.
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Affiliation(s)
- Jason D Linn
- Department of Chemical Engineering and Materials Science, University of Minnesota Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Lucy Liberman
- Department of Chemical Engineering and Materials Science, University of Minnesota Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Christopher A P Neal
- Department of Chemical Engineering and Materials Science, University of Minnesota Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
| | - Michelle A Calabrese
- Department of Chemical Engineering and Materials Science, University of Minnesota Twin Cities, 421 Washington Ave SE, Minneapolis, MN 55455, USA
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Jung S, MacConaghy KI, Guarnieri MT, Kaar JL, Stoykovich MP. Quantification of Metabolic Products from Microbial Hosts in Complex Media Using Optically Diffracting Hydrogels. ACS APPLIED BIO MATERIALS 2022; 5:1252-1258. [PMID: 35166523 DOI: 10.1021/acsabm.1c01267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We herein describe a highly versatile platform approach for the in situ and real-time screening of microbial biocatalysts for enhanced production of bioproducts using photonic crystal hydrogels. This approach was demonstrated by preparing optically diffracting films based on polymerized N-isopropylacrylamide that contracted in the presence of alcohols and organic acids. The hydrogel films were prepared in a microwell plate format, which allows for high-throughput screening, and characterized optically using a microwell plate reader. While demonstrating the ability to detect a broad range of relevant alcohols and organic acids, we showed that the response of the films correlated strongly with the octanol-water partition coefficient (log P) of the analyte. Differences in the secretion of ethanol and succinic acid from strains of Zymomonas mobilis and Actinobacillus succinogenes, respectively, were further detected via optical characterization of the films. These differences, which in some cases were as low as ∼3 g/L, were confirmed by high-performance liquid chromatography, thereby demonstrating the sensitivity of this approach. Our findings highlight the potential utility of this multiplexed approach for the detection of small organic analytes in complex biological media, which overcomes a major challenge in conventional optical sensing methods.
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Affiliation(s)
- Sukwon Jung
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Kelsey I MacConaghy
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Michael T Guarnieri
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Joel L Kaar
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Mark P Stoykovich
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
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Paul PK, Treetong A, Suedee R. Biomimetic insulin-imprinted polymer nanoparticles as a potential oral drug delivery system. ACTA PHARMACEUTICA 2017; 67:149-168. [PMID: 28590908 DOI: 10.1515/acph-2017-0020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/02/2017] [Indexed: 12/22/2022]
Abstract
In this study, we investigate molecularly imprinted polymers (MIPs), which form a three-dimensional image of the region at and around the active binding sites of pharmaceutically active insulin or are analogous to b cells bound to insulin. This approach was employed to create a welldefined structure within the nanospace cavities that make up functional monomers by cross-linking. The obtained MIPs exhibited a high adsorption capacity for the target insulin, which showed a significantly higher release of insulin in solution at pH 7.4 than at pH 1.2. In vivo studies on diabetic Wistar rats showed that the fast onset within 2 h is similar to subcutaneous injection with a maximum at 4 h, giving an engaged function responsible for the duration of glucose reduction for up to 24 h. These MIPs, prepared as nanosized material, may open a new horizon for oral insulin delivery.
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Affiliation(s)
- Pijush Kumar Paul
- Molecular Recognition Materials Research Unit, Nanotec-PSU Center of Excellence on Drug Delivery System Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University Hatyai, Songkhla , 90112, Thailand
| | - Alongkot Treetong
- National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park Phahonyothin Road Pathum Thani 12120, Pathum Thani , Thailand
| | - Roongnapa Suedee
- Molecular Recognition Materials Research Unit, Nanotec-PSU Center of Excellence on Drug Delivery System Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University Hatyai, Songkhla , 90112, Thailand
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Shi T, Li D, Li G, Zhang Y, Xu K, Lu L. Modeling and Measurement of Correlation between Blood and Interstitial Glucose Changes. J Diabetes Res 2016; 2016:4596316. [PMID: 27239479 PMCID: PMC4863111 DOI: 10.1155/2016/4596316] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/03/2016] [Indexed: 11/18/2022] Open
Abstract
One of the most effective methods for continuous blood glucose monitoring is to continuously measure glucose in the interstitial fluid (ISF). However, multiple physiological factors can modulate glucose concentrations and affect the lag phase between blood and ISF glucose changes. This study aims to develop a compensatory tool for measuring the delay in ISF glucose variations in reference to blood glucose changes. A theoretical model was developed based on biophysics and physiology of glucose transport in the microcirculation system. Blood and interstitial fluid glucose changes were measured in mice and rats by fluorescent and isotope methods, respectively. Computer simulation mimicked curves were fitted with data resulting from fluorescent measurements of mice and isotope measurements of rats, indicating that there were lag times for ISF glucose changes. It also showed that there was a required diffusion distance for glucose to travel from center of capillaries to interstitial space in both mouse and rat models. We conclude that it is feasible with the developed model to continuously monitor dynamic changes of blood glucose concentration through measuring glucose changes in ISF with high accuracy, which requires correct parameters for determining and compensating for the delay time of glucose changes in ISF.
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Affiliation(s)
- Ting Shi
- College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
- Department of Medicine, University of California School of Medicine, Torrance, CA 90502, USA
| | - Dachao Li
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Guoqing Li
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Yiming Zhang
- College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China
| | - Kexin Xu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
- *Kexin Xu: and
| | - Luo Lu
- Department of Medicine, University of California School of Medicine, Torrance, CA 90502, USA
- *Luo Lu:
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Man Y, Peng G, Wang J, Lv X, Deng Y. Microfluidic chip with thermoresponsive boronate affinity for the capture-release ofcis-diol biomolecules. J Sep Sci 2014; 38:339-45. [DOI: 10.1002/jssc.201400725] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/05/2014] [Accepted: 10/27/2014] [Indexed: 01/18/2023]
Affiliation(s)
- Yan Man
- School of Life Science; Beijing Institute of Technology; Beijing China
| | - Guang Peng
- School of Life Science; Beijing Institute of Technology; Beijing China
| | - Jianshe Wang
- School of Life Science; Beijing Institute of Technology; Beijing China
| | - Xuefei Lv
- School of Life Science; Beijing Institute of Technology; Beijing China
| | - Yulin Deng
- School of Life Science; Beijing Institute of Technology; Beijing China
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Huang X, Leduc C, Ravussin Y, Li S, Davis E, Song B, Li D, Xu K, Accili D, Wang Q, Leibel R, Lin Q. A differential dielectric affinity glucose sensor. LAB ON A CHIP 2014; 14:294-301. [PMID: 24220675 PMCID: PMC3893139 DOI: 10.1039/c3lc51026c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A continuous glucose monitor with a differential dielectric sensor implanted within the subcutaneous tissue that determines the glucose concentration in the interstitial fluid is presented. The device, created using microelectromechanical systems (MEMS) technology, consists of sensing and reference modules that are identical in design and placed in close proximity. Each module contains a microchamber housing a pair of capacitive electrodes residing on the device substrate and embedded in a suspended, perforated polymer diaphragm. The microchambers, enclosed in semi-permeable membranes, are filled with either a polymer solution that has specific affinity to glucose or a glucose-insensitive reference solution. To accurately determine the glucose concentration, changes in the permittivity of the sensing and the reference solutions induced by changes in glucose concentration are measured differentially. In vitro characterization demonstrated the sensor was capable of measuring glucose concentrations from 0 to 500 mg dL(-1) with resolution and accuracy of ~1.7 μg dL(-1) and ~1.74 mg dL(-1), respectively. In addition, device drift was reduced to 1.4% (uncontrolled environment) and 11% (5 °C of temperature variation) of that from non-differential measurements, indicating significant stability improvements. Preliminary animal testing demonstrated that the differential sensor accurately tracks glucose concentration in blood. This sensor can potentially be used clinically as a subcutaneously implanted continuous monitoring device in diabetic patients.
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Affiliation(s)
- Xian Huang
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
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Huang X, Li S, Davis E, Leduc C, Ravussin Y, Cai H, Song B, Li D, Accili D, Leibel R, Wang Q, Lin Q. A MEMS differential viscometric sensor for affinity glucose detection in continuous glucose monitoring. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2013; 23:55020. [PMID: 23956499 PMCID: PMC3743269 DOI: 10.1088/0960-1317/23/5/055020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Micromachined viscometric affinity glucose sensors have been previously demonstrated using vibrational cantilever and diaphragm. These devices featured a single glucose detection module that determines glucose concentrations through viscosity changes of glucose-sensitive polymer solutions. However, fluctuations in temperature and other environmental parameters might potentially affect the stability and reliability of these devices, creating complexity in their applications in subcutaneously implanted continuous glucose monitoring (CGM). To address these issues, we present a MEMS differential sensor that can effectively reject environmental disturbances while allowing accurate glucose detection. The sensor consists of two magnetically driven vibrating diaphragms situated inside microchambers filled with a boronic-acid based glucose-sensing solution and a reference solution insensitive to glucose. Glucose concentrations can be accurately determined by characteristics of the diaphragm vibration through differential capacitive detection. Our in-vitro and preliminary in-vivo experimental data demonstrate the potential of this sensor for highly stable subcutaneous CGM applications.
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Affiliation(s)
- Xian Huang
- Department of Mechanical Engineering, Columbia University, New York, NY 10027
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Ashaduzzaman M, Kunitake M. Poly(methylmethacrylate)-block-poly(N-hydroxyethylacrylamide) diblock copolymers: direct ATRP synthesis and characterization. IRANIAN POLYMER JOURNAL 2013. [DOI: 10.1007/s13726-013-0150-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Huang X, Leduc C, Ravussin Y, Li S, Davis E, Song B, Wang Q, Accili D, Leibel R, Lin Q. Continuous monitoring of glucose in subcutaneous tissue using microfabricated differential affinity sensors. J Diabetes Sci Technol 2012; 6:1436-44. [PMID: 23294791 PMCID: PMC3570886 DOI: 10.1177/193229681200600625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We describe miniaturized differential glucose sensors based on affinity binding between glucose and a synthetic polymer. The sensors possess excellent resistance to environmental disturbances and can potentially allow wireless measurements of glucose concentrations within interstitial fluid in subcutaneous tissue for long-term, stable continuous glucose monitoring (CGM). METHODS The sensors are constructed using microelectromechanical systems (MEMS) technology and exploit poly(N-hydroxy-ethyl acrylamide-ran-3-acrylamidophenylboronic acid) (PHEAA-ran-PAAPBA), a glucose-binding polymer with excellent specificity, reversibility, and stability. Two sensing approaches have been investigated, which respectively, use a pair of magnetically actuated diaphragms and perforated electrodes to differentially measure the glucose-binding-induced changes in the viscosity and permittivity of the PHEAA-ran-PAAPBA solution with respect to a reference, glucose-unresponsive polymer solution. RESULTS In vivo characterization of the MEMS affinity sensors were performed by controlling blood glucose concentrations of laboratory mice by exogenous glucose and insulin administration. The sensors experienced an 8-30 min initialization period after implantation and then closely tracked commercial capillary glucose meter readings with time lags ranging from 0-15 min during rapid glucose concentration changes. Clarke error grid plots obtained from sensor calibration suggest that, for the viscometric and dielectric sensors, respectively, approximately 95% (in the hyperglycemic range) and 84% (ranging from hypoglycemic to hyperglycemic glucose concentrations) of measurement points were clinically accurate, while 5% and 16% of the points were clinically acceptable. CONCLUSIONS The miniaturized MEMS sensors explore differential measurements of affinity glucose recognition. In vivo testing demonstrated excellent accuracy and stability, suggesting that the devices hold the potential to enable long-term and reliable CGM in clinical applications.
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Affiliation(s)
- Xian Huang
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
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