- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Facile fabrication of cross-linked fluorescent organic nanoparticles with aggregation-induced emission characteristic via the thiol-ene click reaction and their potential for biological imaging
摘要： Over the past several years, the biomedical applications of fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature have been extensively explored because the AIE-active FONs could effectively overcome the aggregation caused quenching (ACQ) effect of FONs based on conventional organic dyes. The development of novel methods for synthesis of AIE-active FONs plays a centre role for their biomedical applications. In this work, we reported a facile one-step thiol-ene click reaction for fabrication of AIE-active FONs through conjugation of acrylated PEG and AIE-active tetraphenylethylene (TPE) with two ene bonds using pentaerythritol tetra(3-mercaptopropionate) as the linkage. The successful synthesis of TPE containing AIE-active copolymers was evidenced by various characterization techniques. The particle size and fluorescence properties of the resultant TPE-S-PEG copolymers were evaluated by transmission electronic microscopy and fluorescence spectroscopy. Moreover, the cell viability and cell uptake behavior was also examined to evaluate their potential for biological imaging. We demonstrated that the cross-linked TPE-S-PEG show small size, high water dispersibility, low cytotoxicity and strong fluorescence for tracing. All of these advantages endow the TPE-S-PEG FONs great potential for biological imaging applications. Furthermore, this novel click reaction can take place under mild experimental conditions with high efficiency. It could be also further expanded for preparation of multifunctional AIE-active materials due to the universality of the thiol-ene click reaction and good precursor applicapability. Taken together, we have developed a novel and effective thiol-ene click reaction to fabricate the cross-linked AIE-active FONs, which display excellent physicochemical and biological properties and are promising for biomedical applications.
关键词： thiol-ene click reaction,Aggregation-induced emission,biomedical applications,fluorescent organic nanoparticles,cross-linked FONs
更新于2025-09-23 15:23:52
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Gamma irradiated poly (methyl methacrylate)-reduced graphene oxide composite thin films for multifunctional applications
摘要： Poly (methyl methacrylate) (PMMA)-Reduced Graphene Oxide (rGO) (PrGO) composite films were fabricated by solvent evaporation technique and exposed to gamma radiation at different dosages viz. 25 kGy, 50 kGy and 100 kGy. The XRD analysis revealed the phases of PMMA and rGO and further confirmed the semi-crystalline nature of PMMA. The irradiation also decreased the peak intensities of the functional groups of PMMA and rGO. At 50 kGy irradiation, lamellar structures were formed on the surface of the films (50 kGy) due to the thermal fluctuations whereas, at higher dosage (100 kGy), pores were formed. The surface roughness and contact angle were enhanced on 50 kGy sample. The drug impregnated PrGO50 and PrGO100 samples showed sustained and burst release of drug respectively and in addition exhibited a better zone of inhibition against E. coli bacteria. All the samples were hemocompatible in nature. Fibroblast proliferation was enhanced with no cytotoxic effect on 50 kGy samples. Hence, the gamma irradiated samples could be an excellent candidate for biosensing and biomedical applications.
关键词： Biomedical Applications,Polymer,Bioactive,Reduced-graphene oxide composites
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE ANDESCON - Santiago de Cali, Colombia (2018.8.22-2018.8.24)] 2018 IEEE ANDESCON - Development of a Low-Cost Pulse Oximeter Simulator for Educational Purposes
摘要： Medical instrumentation devices are crucial to determine health conditions in humans. Teaching biomedical instrumentation requires a perfect combination of practice and theory. Therefore, the use of physiological signals simulators such as a %SpO2 becomes important as a teaching strategy. The objective of this project is to develop and implement an oxygen saturation simulator, for use in the biomedical instrumentation courses. The development process began by establishing the requirements of the simulator and designing a graphical user interface to control the simulator parameters. Subsequently, a circuit capable of materializing the simulated signals from the interface was developed, together with a probe or artificial finger that was to be introduced inside the objective pulse oximeter. Finally, the systems were integrated into the simulator
关键词： simulation,low cost,Pulse oximetry,biomedical instrumentation,education
更新于2025-09-23 15:23:52
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A Low Power and Fast Tracking Light-to-Frequency Converter with Adaptive Power Scaling for Blood SpO2 Sensing
摘要： This paper presents a monolithic low power and fast tracking light-to-frequency converter for blood SpO2 sensing. Normally, the tracking speed and the power consumption are two contradictory characteristics. However different gain-bandwidth specifications for various ambient light intensities allow the dynamically optimization of the power consumption according to the light intensity. In this paper, the amplifier power consumption is adaptively scaled by the generated light-intensity-positively-correlated control voltage. Thus, the chip total power consumption at low light intensity is significantly decreased. Moreover, the proposed adaptive power scaling is achieved with a continuous analog domain, which does not introduce extra switching noise. The proposed light-to-frequency sensor chip is fabricated by using 0.35 μm CMOS technology with a die area of 1 × 0.9 mm2. The measurement results show that the pulse light response for any light intensity is no longer than two new output square-wave cycles. The maximum total current consumption is 1.9 mA from a 3.3 V supply voltage, which can be adaptively scaled down to only 0.7 mA if the output frequency is about 25 KHz or lower. The minimum operational supply voltage of the proposed sensor chip is 2.5 V in the temperature range of -25 to 80 oC with 4 KV ESD level (HBM).
关键词： light-to-frequency converter,low power,fast tracking,blood oxygen,biomedical sensor
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Cleveland, OH, USA (2018.10.17-2018.10.19)] 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - A 6.25 Mbps, 12.4 pJ/bit DQPSK Backscatter Wireless Uplink for the NeuroDisc Brain-Computer Interface
摘要： Wireless brain-computer interfaces (BCIs) used for fundamental neuroscience research in freely moving non-human primates (NHPs) require communication systems capable of transferring large volumes of recorded neural data while consuming minimal power. We introduce a 6.25 Mbps differential quadrature phase-shift keying (DQPSK) backscatter wireless uplink for the NeuroDisc BCI, operating in the 902-928 MHz industrial, scientific, and medical (ISM)-band. The backscatter uplink consumes 77.5 μW (only 0.06% of the system power budget), yielding a communication energy efficiency of 12.4 pJ/bit, while the measured error vector magnitude of the DQPSK constellation is 9.69%. The neural recording front-end has a measured input-referred noise of 2.35 μVrms at a maximum sampling rate of 20 kSps. We present end-to-end recording and wireless uplink validation with pre-recorded neural data as well as in vivo recordings from a pigtail macaque.
关键词： implanted biomedical devices,neural recording,backscatter communication
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Cleveland, OH, USA (2018.10.17-2018.10.19)] 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Multi-coil High Efficiency Wireless Charger System for Hermetically Sealed Biomedical Implants
摘要： Biomedical inductively-coupled transcutaneous implants with internal batteries typically rely on a two-coil charging system which places fundamental and practical limits such as requiring short coil-to-coil distance for useful Wireless Power Transfer (WPT) efficiency. In case of hermetic metal enclosures equipped with finite size dielectric window for magnetic flux penetration, two-coil configurations can induce substantial additional loss due to eddy currents generated on e.g. Ti metal surface by fringing B-fields. Dissipative losses are unwelcome as they increase the temperature of the implant. We focus here on high-performance implants with internal electronic circuits and power source which require frequent, rapid battery recharging. The case example is a wireless broadband neural recording device capable of high data rate transmission (> 40 Mbps). We describe a compact planar four-coil configuration to achieve efficient Wireless Power Transfer (WPT) across tissue layers exceeding 1 cm. For the device geometry discussed here, our system transfers up to 73 % and 46 % of RF energy across 16 mm-separated source-to-load coil, in absence or presence of a Ti-enclosure which embeds the energy harvesting coil pair respectively. Thin sheets of ferrites are integrated to enhance local B-fields. We are able to charge a 200 mAh medical-grade battery to useful 84% of its full charge capacity (near current saturation) within 1 hour through a sapphire window integrated with the hermetic Ti- enclosure. The measured temperature increase is 2.1 ℃ with Ti-can immersed in still saline, slightly above FDA requirements or more recent ISO standards. From physiological models, we expect that active cooling by body tissue surrounding the implant (such as microvasculature perfusion) will provide for a safe and efficient WPT method.
关键词： biomedical implants,inductive charging,Eddy current heating,wireless charging
更新于2025-09-23 15:23:52
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A thermo-sensitive fluorescent agent based method for excitation light leakage rejection for fluorescence molecular tomography
摘要： Fluorescence molecular tomography (FMT) is widely used in preclinical oncology research. FMT is the only imaging technique able to provide three-dimensional distribution of fluorescent probes within thick highly scattering media. However, its integration into clinical medicine has been hampered by its low spatial resolution caused by the undetermined and ill-posed nature of its reconstruction algorithm. Another major factor degrading the quality of FMT images is the large backscattered excitation light component leaking through the rejection filters and coinciding with the weak fluorescent signal arising from a low tissue fluorescence concentration. In this paper, we present a new method based on the use of a novel thermo-sensitive fluorescence probe. In fact, the excitation light leakage is accurately estimated from a set of measurements performed at different temperatures and then is corrected for in the tomographic data. The obtained results show a considerable improvement in both spatial resolution and quantitative accuracy of FMT images due to the proper correction of fluorescent signals.
关键词： Excitation Light Leakage,Biomedical Imaging,Fluorescence Molecular Tomography
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Mon Tresor, Plaine Magnien, Mauritius (2018.12.6-2018.12.7)] 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - OTA-C Filters for Biomedical Signal Processing Applications using Hybrid CMOS-CNFET Technology
摘要： Analog filters for biomedical signal processing applications deals with very slow or low frequency electrical activities of the physiological signals. This paper proposes first order, second order, fifth order elliptic low pass, second order notch and high pass OTA-C filters using hybrid CMOS-CNFET technology. Carbon Nanotube Field Effect Transistors (CNFETs) and CMOS devises can be heterogeneously integrated on a single 3-D chip to realize important signal processing building blocks such as OTA-C filters. Proposed circuits use Operational Transconductance Amplifier (OTA) as a building block for OTA-C filters. Realized filter circuits satisfy ultra-low power consumption requirement of wearable and implantable biomedical devices. The transistors used in the circuit operate in weak inversion to achieve ultra-low power consumption.
关键词： Noise Filtering,OTA-C Filters,Biomedical Signal Processing,Carbon Nanotube Field Effect Transistors
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Vilnius, Lithuania (2018.11.8-2018.11.10)] 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Deep Neural Network-based Feature Descriptor for Retinal Image Registration
摘要： Feature description is an important step in image registration workflow. Discriminative power of feature descriptors affects feature matching performance and overall results of image registration. Deep Neural Network-based (DNN) feature descriptors are emerging trend in image registration tasks, often performing equally or better than hand-crafted ones. However, there are no learned local feature descriptors, specifically trained for human retinal image registration. In this paper we propose DNN-based feature descriptor that was trained on retinal image patches and compare it to well-known hand-crafted feature descriptors. Training dataset of image patches was compiled from nine online datasets of eye fundus images. Learned feature descriptor was compared to other descriptors using Fundus Image Registration dataset (FIRE), measuring amount of correctly matched ground truth points (Rank-1 metric) after feature description. We compare the performance of various feature descriptors applied for retinal image feature matching.
关键词： artificial neural networks,biomedical imaging,machine learning,image registration,retinal images,feature descriptors
更新于2025-09-23 15:22:29
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[IEEE 2018 Innovations in Intelligent Systems and Applications (INISTA) - Thessaloniki (2018.7.3-2018.7.5)] 2018 Innovations in Intelligent Systems and Applications (INISTA) - Piezologist: A Novel Wearable Piezoelectric-based Cardiorespiratory Monitoring System
摘要： In this paper, the design, prototyping and software development of a novel wearable cardiorespiratory parameters monitoring sensor and software applications illustrated. Piezologist is an unobtrusive chest worn device. It comprises a patch-type sensor and a mobile application. The sensor utilizes piezoelectric material as the cardiorespiratory signal sensing component and MetaWearC board as the signal acquisition unit. The board also comes with Bluetooth Low Energy (BLE) support which is utilized for the raw signal transmission. The novelty aspect of the system rests on the fact that not only using a single cheap piezoelectric sheet common cardiorespiratory parameters (such as heart rate, respiration rate, and cycles) were obtained similar to previous studies but ECG waveform and blood pressure data were also extracted successfully using the same sensor. In addition, sensor packaging design and prototyping and their effect on the acquired signal strength on one hand and the package size (volume and weight) on the other hand were studied and reported. For performance validation purpose, the developed cardiorespiratory monitoring system results were validated against two commercial sensor devices namely 3-lead ECG sensor from eHealth sensor kit and Zephyr belt-type BioHarness sensor, and the results were reported herein. The validation process outcomes confirmed that the cardiorespiratory signals extracted using Piezologist conform with a heartbeat, respiratory cycle and ECG waveform obtained using the commercial sensors. Furthermore, a usability study was conducted to compare the user experience offered by Piezologist for measuring cardiorespiratory parameters against the commercially available sensors. The study highlighted the potential that Piezologist will take over the commercial available belt-type, watch-type and 3-lead ECG sensors.
关键词： biomedical signal processing,heart rate extraction,wearable sensors,Sensors,Vital signs,ECG waveform,Home healthcare,cardiorespiratory,Heartbeats,mobile healthcare,Respiration rate
更新于2025-09-23 15:22:29