Microneedle-based system for minimally invasive continuous monitoring of glucose in the dermal interstitial fluid

Author(s):  
Federico Ribet ◽  
Goran Stemme ◽  
Nielas Roxhed
1977 ◽  
Vol 42 (4) ◽  
pp. 476-482 ◽  
Author(s):  
G. Bo ◽  
A. Hauge ◽  
G. Nicolaysen

We have investigated the influence of changes in alveolar pressure (PAlv) and in lung volume on the net transvascular fluid filtration rate (FFR). The preparation was isolated, perfused zone III rabbit lungs. In observation periods the outflow pressure was kept constant at a level generally causing net filtration. All pressures were measured relative to atmospheric. FFR was measured by continuous monitoring of preparation weight. Elevation of Palv at constant lung volume caused reversible reductions in FFR, also at constant capillary hydrostatic pressure (Pa-V less than 2 Torr). Increases in lung volume at constant PAlv caused reversible increases in FFR. When both PAlv and Ptp were increased a reduction in FFR was seen in the majority of cases. We conclude that at constant pulmonary arterial pressure, the size and the direction of the influence of positive airway pressure on FFR depend on the relative change in lung volume and in alveolar pressure per se. Under the present experimental conditions a rise in PAlv will be transmitted to interstitial fluid pressure and affect the transvascular fluid balance.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gun Jin Kim ◽  
Kyu Oh Kim

Abstract Micro- and nanofiber (NF) hydrogels fabricated by electrospinning to typically exhibit outstanding high porosity and specific surface area under hydrated conditions. However, the high crystallinity of NFs limits the achievement of transparency via electrospinning. Transparent poly(vinyl alcohol)/β-cyclodextrin polymer NF hydrogels contacted with reverse iontophoresis electrodes were prepared for the development of a non-invasive continuous monitoring biosensor platform of interstitial fluid glucose levels reaching ~ 1 mM. We designed the PVA/BTCA/β-CD/GOx/AuNPs NF hydrogels, which exhibit flexibility, biocompatibility, excellent absorptivity (DI water: 21.9 ± 1.9, PBS: 41.91 ± 3.4), good mechanical properties (dried: 12.1 MPa, wetted: 5.33 MPa), and high enzyme activity of 76.3%. Owing to the unique features of PVA/β-CD/GOx containing AuNPs NF hydrogels, such as high permeability to bio-substrates and rapid electron transfer, our biosensors demonstrate excellent sensing performance with a wide linear range, high sensitivity(47.2 μA mM−1), low sensing limit (0.01 mM), and rapid response time (< 15 s). The results indicate that the PVA/BTCA/β-CD/GOx/AuNPs NF hydrogel patch sensor can measure the glucose concentration in human serum and holds massive potential for future clinical applications.


1981 ◽  
Vol 9 (12) ◽  
pp. 845-851 ◽  
Author(s):  
BRUCE A. McKINLEY ◽  
BRUCE A. HOUTCHENS ◽  
JIRI JANATA

Small ◽  
2020 ◽  
Vol 16 (16) ◽  
pp. 1905910 ◽  
Author(s):  
Jixiang Zhu ◽  
Xingwu Zhou ◽  
Han‐Jun Kim ◽  
Moyuan Qu ◽  
Xing Jiang ◽  
...  

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 580 ◽  
Author(s):  
Paolo Bollella ◽  
Sanjiv Sharma ◽  
Anthony E. G. Cass ◽  
Federico Tasca ◽  
Riccarda Antiochia

In this paper, we present the first highly porous gold (h-PG) microneedles-based second-generation biosensor for minimally invasive monitoring of glucose in artificial interstitial fluid (ISF). A highly porous microneedles-based electrode was prepared by a simple electrochemical self-templating method that involves two steps, gold electrodeposition and hydrogen bubbling at the electrode, which were realized by applying a potential of −2 V versus a saturated calomel electrode (SCE). The highly porous gold surface of the microneedles was modified by immobilization of 6-(ferrocenyl)hexanethiol (FcSH) as a redox mediator and subsequently by immobilization of a flavin adenine dinucleotide glucose dehydrogenase (FAD-GDH) enzyme using a drop-casting method. The microneedles-based FcSH/FAD-GDH biosensor allows for the detection of glucose in artificial interstitial fluid with an extended linear range (0.1–10 mM), high sensitivity (50.86 µA cm−2 mM−1), stability (20% signal loss after 30 days), selectivity (only ascorbic acid showed a response about 10% of glucose signal), and a short response time (3 s). These properties were favourably compared to other microneedles-based glucose biosensors reported in the literature. Finally, the microneedle-arrays-based second-generation biosensor for glucose detection was tested in artificial interstitial fluid opportunely spiked with different concentrations of glucose (simulating healthy physiological conditions while fasting and after lunch) and by placing the electrode into a simulated chitosan/agarose hydrogel skin model embedded in the artificial ISF (continuous glucose monitoring). The obtained current signals had a lag-time of about 2 min compared to the experiments in solution, but they fit perfectly into the linearity range of the biosensor (0.1–10 mM). These promising results show that the proposed h-PG microneedles-based sensor could be used as a wearable, disposable, user-friendly, and automated diagnostic tool for diabetes patients.


2002 ◽  
Vol 87 (1) ◽  
pp. 150-158 ◽  
Author(s):  
Meinhard Knoll ◽  
Stefan Adam ◽  
Elisabeth Bahr ◽  
Jochen Eshold ◽  
Bernd Roß ◽  
...  

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