Browsing by Author "Istif, Emin"

Now showing 1 - 11 of 11

Citation Count: 18
Biodegradable Piezoelectric Polymers: Recent Advancements in Materials and Applications
(Wiley, 2023) Istıf, Emın; Bathaei, Mohammad Javad; Istif, Emin; Karimi, Seyed Nasir Hosseini; Beker, Levent
Recent materials, microfabrication, and biotechnology improvements have introduced numerous exciting bioelectronic devices based on piezoelectric materials. There is an intriguing evolution from conventional unrecyclable materials to biodegradable, green, and biocompatible functional materials. As a fundamental electromechanical coupling material in numerous applications, novel piezoelectric materials with a feature of degradability and desired electrical and mechanical properties are being developed for future wearable and implantable bioelectronics. These bioelectronics can be easily integrated with biological systems for applications, including sensing physiological signals, diagnosing medical problems, opening the blood-brain barrier, and stimulating healing or tissue growth. Therefore, the generation of piezoelectricity from natural and synthetic bioresorbable polymers has drawn great attention in the research field. Herein, the significant and recent advancements in biodegradable piezoelectric materials, including natural and synthetic polymers, their principles, advanced applications, and challenges for medical uses, are reviewed thoroughly. The degradation methods of these piezoelectric materials through in vitro and in vivo studies are also investigated. These improvements in biodegradable piezoelectric materials and microsystems could enable new applications in the biomedical field. In the end, potential research opportunities regarding the practical applications are pointed out that might be significant for new materials research.
Citation Count: 0
Continuous Glycemic Monitoring Enabled by A Wi-Fi Energy-Harvesting Wearable Sweat-Sensing Patch
(Wiley, 2024) Istıf, Emın; Abbasiasl, Taher; Mirzajani, Hadi; Istif, Emin; Akhtar, Muhammad Junaid; Cakir, Cengiz; Beker, Levent
Continuous monitoring of multiple physiological parameters, such as glucose levels, temperature, and heart rate variability (HRV) is crucial for effective diabetes management and mitigating the risks associated with hypoglycemic events. These events often occur without apparent symptoms, posing a challenge for diabetic patients in managing their condition. Therefore, a non-invasive wearable device capable of continuously measuring multiple body signals to predict hypoglycemic events would be highly beneficial. In this study, a wearable patch that continuously measures glucose, temperature, and HRV is presented. The device uses a novel power harvesting system to convert radiofrequency (RF) signals with the frequency of 2.45 GHz to direct current (DC) signals to extend the battery life for further continuous monitoring. The patch is small and has a conformal structure that can easily fit onto different body parts. The screen-printed glucose sensor demonstrates a sensitivity of 10.3 nA cm-2 mu M-1, a limit of detection (LOD) of 8.9 mu M, and a limit of quantification (LOQ) of 27 mu M. The device employs a photoplethysmography (PPG) module with a peak-finding algorithm to calculate the HRV values. In vivo experiments demonstrate the validation of the device's proper operation in glucose, HRV, and temperature measurement. This study introduces a wearable patch for diabetes management, employing a unique Wi-Fi energy harvesting system for extended battery life. The device's conformal structure enables effortless placement on the body, providing continuous monitoring of glucose, HRV, and temperature. The platform presents a non-invasive physiological monitoring approach that enhances diabetes care by offering real-time data in a compact and efficient design. image
Citation Count: 0
Investigation of dynamic micromechanical properties of biodegradable elastic material by continuous stiffness measurement analysis
(Sage Publications Ltd, 2023) Istıf, Emın; Istif, Emin; Bathaei, Mohammad Javad; Beker, Levent
Micromechanical properties of polymeric materials play a critical role in various biological applications in terms of their biocompatibility and mechanical durability. Apart from material properties such as modulus and density, viscoelastic properties play a crucial role during the design and fabrication of devices. Here, we investigated the viscoelastic properties of poly (glycerol sebacate) (PGS), a widely used bioresorbable elastic material, through the nanoindentation technique, configured by the continuous stiffness measurement (CSM) method at frequencies from 10 Hz to 50 Hz. The results revealed that the storage modulus (E') depends on the test frequency and cannot be ignored as the results showed significant changes. Additionally, increasing the curing temperature of PGS specimens between 150 to 170 & DEG;C allows modifying the storage modulus of samples between 0.52 MPa and 1.05 MPa at 10 Hz. The results were also confirmed using the dynamic mechanical measurements to validate the reliability of the CSM nanoindentation technique.
Citation Count: 0
A low-cost wireless miniaturized device for food spoilage monitoring
(Nature Portfolio, 2023) Istıf, Emın; Beker, Levent
[Abstract Not Available]
Citation Count: 12
Miniaturized wireless sensor enables real-time monitoring of food spoilage
(Nature Portfolio, 2023) Istıf, Emın; Mirzajani, Hadi; Dag, Cagdas; Mirlou, Fariborz; Ozuaciksoz, Elif Yaren; Cakir, Cengiz; Koydemir, Hatice Ceylan
Food spoilage results in food waste and food-borne diseases. Yet, standard laboratory tests to determine spoilage (mainly volatile biogenic amines) are not performed regularly by supply chain personnel or end customers. Here we developed a poly(styrene-co-maleic anhydride)-based, miniature (2 x 2 cm(2)) sensor for on-demand spoilage analysis via mobile phones. To demonstrate a real-life application, the wireless sensor was embedded into packaged chicken and beef; consecutive readings from meat samples using the sensor under various storage conditions enabled the monitoring of spoilage. While samples stored at room temperature showed an almost 700% change in sensor response on the third day, those stored in the freezer resulted in an insignificant change in sensor output. The proposed low-cost, miniature wireless sensor nodes can be integrated into packaged foods, helping consumers and suppliers detect spoilage of protein-rich foods on demand, and ultimately preventing food waste and food-borne diseases. Standard tests to determine food spoilage are costly and time consuming. A poly(styrene-co-maleic anhydride)-based sensor offers a low-cost alternative that can be linked to mobile phones for real-time spoilage analysis. The device was tested on chicken and beef samples under various storage conditions.
Citation Count: 0
Multicolor Photoluminescence from Nonconjugated Poly(3,4-dihydropyran) Nanoparticles
(Amer Chemical Soc, 2023) Istıf, Emın; Bui, Anh Thy; Jonusauskas, Gediminas; McClenaghan, Nathan D.; Istif, Emin; Mantione, Daniele; Pavlopoulou, Eleni
In recent years, nonconjugated organic luminophores arereceivingconsiderable interest from the scientific community, offering a newconceptual basis for the development of alternative photoluminescence-basedtechnologies. In this work, the polymerization of 3,4-dihydropyranwas exploited for the preparation of nonconjugated photoluminescentpolymer nanoparticles. Remarkably, excitation-dependent multicoloremission ranging from blue to yellow was observed in both solid andsolution. In contrast with similar materials, this behavior was notattributed to aggregation-induced emission, but rather to the presenceof independent, noninteracting chromophores located on the polymerstructure. Structural and optical characterizations along with furtherchemical modifications suggest that the emission is related to thepresence of acetal groups formed by ring-opening polymerization. Inaddition, it was shown that the removal of unsaturated structurescould enhance the photoluminescence quantum yield of the polymer (QY)up to 0.20 (lambda(ex) = 355 nm). This work provides a newtype of nonconjugated organic luminophore with both high QY and multicoloremission.
Citation Count: 0
Near-Infrared Triggered Degradation for Transient Electronics
(Amer Chemical Soc, 2024) Istıf, Emın; Ali, Mohsin; Ozuaciksoz, Elif Yaren; Morova, Yagiz; Beker, Levent
Electronics that disintegrate after stable operation present exciting opportunities for niche medical implant and consumer electronics applications. The disintegration of these devices can be initiated due to their medium conditions or triggered by external stimuli, which enables on-demand transition. An external stimulation method that can penetrate deep inside the body could revolutionize the use of transient electronics as implantable medical devices (IMDs), eliminating the need for secondary surgery to remove the IMDs. We report near-infrared (NIR) light-triggered transition of metastable cyclic poly-(phthalaldehyde) (cPPA) polymers. The transition of the encapsulation layer is achieved through the conversion of NIR light to heat, facilitated by bioresorbable metals, such as molybdenum (Mo). We reported a rapid degradation of cPPA encapsulation layer about 1 min, and the rate of degradation can be controlled by laser power and exposure time. This study offers a new approach for light triggerable transient electronics for IMDs due to the deep penetration depth of NIR light through to organs and tissues.
Citation Count: 0
Paper integrated microfluidic contact lens for colorimetric glucose detection
(Royal Soc Chemistry, 2024) Istıf, Emın; Abbasiasl, Taher; Das, Ritu; Istif, Emin; Yener, Umut Can; Beker, Levent
Contact lenses offer a simple, cost-effective, and non-invasive method for in situ real-time analysis of various biomarkers. Electro-chemical sensors are integrated into contact lenses for analysis of various biomarkers. However, they suffer from rigid electronic components and connections, leading to eye irritation and biomarker concentration deviation. Here, a flexible and microfluidic integrated paper-based contact lens for colorimetric analysis of glucose was implemented. Facilitating a three-dimensional (3D) printer for lens fabrication eliminates cumbersome cleanroom processes and provides a simple, batch compatible process. Due to the capillary force of the filter paper, the sample was routed to detection chambers inside microchannels, and it allowed further colorimetric detection. The paper-embedded microfluidic contact lens successfully detects glucose down to 2 mM within similar to 10 s. The small dimension of the microfluidic system enables detection of glucose levels as low as 5 mu l. The results show the potential of the presented approach to analyze glucose concentration in a rapid manner. It is demonstrated that the fabricated contact lens can successfully detect glucose levels of diabetic patients. Contact lenses offer a simple, cost-effective, and non-invasive method for in situ real-time analysis of various biomarkers.
Citation Count: 19
Photolithography-Based Microfabrication of Biodegradable Flexible and Stretchable Sensors
(Wiley-V C H Verlag Gmbh, 2023) Istıf, Emın; Singh, Rahul; Mirzajani, Hadi; Istif, Emin; Akhtar, Muhammad Junaid; Abbasiasl, Taher; Beker, Levent
Biodegradable sensors based on integrating conductive layers with polymeric materials in flexible and stretchable forms have been established. However, the lack of a generalized microfabrication method results in large-sized, low spatial density, and low device yield compared to the silicon-based devices manufactured via batch-compatible microfabrication processes. Here, a batch fabrication-compatible photolithography-based microfabrication approach for biodegradable and highly miniaturized essential sensor components is presented on flexible and stretchable substrates. Up to 1600 devices are fabricated within a 1 cm(2) footprint and then the functionality of various biodegradable passive electrical components, mechanical sensors, and chemical sensors is demonstrated on flexible and stretchable substrates. The results are highly repeatable and consistent, proving the proposed method's high device yield and high-density potential. This simple, innovative, and robust fabrication recipe allows complete freedom over the applicability of various biodegradable materials with different properties toward the unique application of interests. The process offers a route to utilize standard micro-fabrication procedures toward scalable fabrication of highly miniaturized flexible and stretchable transient sensors and electronics.
Citation Count: 2
A Wearable Touch-Activated Device Integrated with Hollow Microneedles for Continuous Sampling and Sensing of Dermal Interstitial Fluid
(Wiley-v C H verlag Gmbh, 2023) Istıf, Emın; Mirlou, Fariborz; Mirzajani, Hadi; Bathaei, Mohammad Javad; Istif, Emin; Shomalizadeh, Narges; Beker, Levent
Dermal interstitial fluid (ISF) is emerging as a rich source of biomarkers that complements conventional biofluids such as blood and urine. However, the impact of ISF sampling in clinical applications has been limited owing to the challenges associated with extraction. The implementation of microneedle-based wearable devices that can extract dermal ISF in a pain-free and easy-to-use manner has attracted growing attention in recent years. Here, a fully integrated touch-activated wearable device based on a laser-drilled hollow microneedle (HMN) patch for continuous sampling and sensing of dermal ISF is introduced. The developed platform can produce and maintain the required vacuum pressure (as low as approximate to -53 kPa) to collect adequate volumes of ISF (approximate to 2 mu L needle-1 h-1) for medical applications. The vacuum system can be activated through a one-touch finger operation. A parametric study is performed to investigate the effect of microneedle array size, vacuum pressure, and extraction duration on collected ISF. The capability of the proposed platform for continuous health monitoring is further demonstrated by the electrochemical detection of glucose and pH levels of ISF in animal models. This HMN-based system provides an alternative tool to the existing invasive techniques for ISF collection and sensing for medical diagnosis and treatment. A fully-integrated touch-activated wearable device is developed for continuous sampling and electrochemical analysis of interstitial fluid. The elastic self-recovery of the vacuum generation system enables a wide range of negative pressures and extraction rates. The developed device can successfully detect glucose and pH levels and holds the potential for continuous sensing of multiple biomarkers in extracted interstitial fluid.image
Citation Count: 1
A Wearable Touch-Activated Device Integrated with Hollow Microneedles for Continuous Sampling and Sensing of Dermal Interstitial Fluid (Adv. Mater. 2/2024)
(Wiley-v C H verlag Gmbh, 2024) Istıf, Emın; Mirlou, Fariborz; Mirzajani, Hadi; Bathaei, Mohammad Javad; Istif, Emin; Shomalizadeh, Narges; Beker, Levent
[No Abstract Available]