• Effect of astragalus polysaccharides on cancer cells studied by AFM

      Lu, Zhengcheng; Wang, Zuobin; Li, Dayou; Zhu, Wenyu; Wang, Rui; Qu, Kaige; Yan, Jin; University of Bedfordshire; Changchun University of Science and Technology (IEEE, 2021-11-18)
      As a traditional Chinese medicine, astragalus and its products are used in cancer treatment aiming to reduce the side effects of chemotherapy. Cells are the most basic unit of living organisms, and AFM directly obtains information from living cells on the micro/nano scale. Therefore, the use of AFM to study the interaction between astragalus and cells is conducive to a full range of drug efficacy evaluation and provides a new way for drug development. In this paper, astragalus polysaccharides were extracted from astragalus, which were diluted into solutions of different concentrations. Combined with the MTT experiment, the effects of Astragalus polysaccharide on cancer cells and benign cells were studied by AFM.
    • Effect of different trypsin concentrations on SMCC-7721 cell adhesion

      Yan, Jin; Tian, Liguo; Xie, Chenchen; Liu, Yan; Lu, Zhengcheng; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (International Journal of Pharma Medicine and Biological Sciences, 2021-07-03)
      In this work, living human liver cancer cells (SMCC-7721) were exposed to the trypsin solution at the concentrations of 1.5 mg/ml, 2.0 mg/ml, 2.5 mg/ml, 3.0 mg/ml, 3.5 mg/ml and 4.0 mg/ml, respectively. After 2 min of dosing time, the physical and mechanical properties of the cells were detected by Atomic Force Microscope (AFM). With the increase of the trypsin concentration, the adhesion force between the cell and the probe gently decreased. The maximum lateral deflection voltage variation of the probe, which reflected the maximum external force that kept the cells attached to the substrate, was significantly reduced. This work indicates that we may change the cell morphology and regulate the mechanical properties of cells by controlling the concentration of trypsin solution to treat cells, which has important implications for bioengineering and cell manipulation.
    • Effect of SMMC-7721-derived exosomes on hepatocytes studied by AFM

      Ju, Tuoyu; Yang, Fan; Wang, Ying; Song, Zhengxun; Xu, Hongmei; Chen, Yujuan; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2021-11-18)
      Exosomes play an important role in the early diagnosis and development of hepatocellular carcinoma (HCC). In the past, researchers mainly studied the contents of exosomes and the biological mechanism on cells, but the changes of mechanical properties of cells caused by exosomes are not clear. In this study, the changes of mechanical properties of hepatocytes (L-02) co-cultured with exosomes (7721-exos) derived from HCC (SMMC-7721) with low metastatic ability were studied. The 7721-exos were able to promote the proliferation and rearrange the cytoskeleton of L-02 cells. The atomic force microscopy measurement results showed that the height was increased, the adhesion and the elastic modulus were reduced. The effect was concentration dependent. The changes of cell mechanical properties induced by exosomes were of great significance for further studying the mechanism of exosomes.
    • Effects of injection rate profile on combustion process and emissions in a diesel engine

      Bai, Fuqiang; Zhang, Zuowei; Du, Yongchen; Zhang, Fan; Peng, Zhijun; Tianjin University; University of Hertfordshire; University of Bedfordshire (Hindawi, 2017-06-21)
      When multi-injection is implemented in diesel engine via high pressure common-rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid and wedge) of injection rate profiles were investigated. Modelling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline - rectangle (flat) shape of injection rate can have better balance between NOx and soot emissions than other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces highest soot emissions among five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions was produced by triangle shape due to higher peak injection rate.
    • Effects of laser fluence on silicon modification by four-beam laser interference

      Zhao, Le; Wang, Zuobin; Zhang, Jinjin; Yu, Miao; Li, Siwei; Li, Dayou; Yue, Yong; Changchun University of Science and Technology; University of Bedfordshire; Jiaotong-Liverpool University (American Institute of Physics Inc., 2015-12-17)
      This paper discusses the effects of laser fluence on silicon modification by four-beam laser interference. In this work, four-beam laser interference was used to pattern single crystal silicon wafers for the fabrication of surface structures, and the number of laser pulses was applied to the process in air. By controlling the parameters of laser irradiation, different shapes of silicon structures were fabricated. The results were obtained with the single laser fluence of 354 mJ/cm, 495 mJ/cm, and 637 mJ/cm, the pulse repetition rate of 10 Hz, the laser exposure pulses of 30, 100, and 300, the laser wavelength of 1064 nm, and the pulse duration of 7-9 ns. The effects of the heat transfer and the radiation of laser interference plasma on silicon wafer surfaces were investigated. The equations of heat flow and radiation effects of laser plasma of interfering patterns in a four-beam laser interference distribution were proposed to describe their impacts on silicon wafer surfaces. The experimental results have shown that the laser fluence has to be properly selected for the fabrication of well-defined surface structures in a four-beam laser interference process. Laser interference patterns can directly fabricate different shape structures for their corresponding applications.
    • Effects of water injection strategies on oxy-fuel combustion characteristics of a dual-injection spark ignition engine

      Li, Xiang; Pei, Yiqiang; Li, Dayou; Ajmal, Tahmina; Rana, Khaqan-Jim; Aitouche, Abdel; Mobasheri, Raouf; Peng, Zhijun; University of Bedfordshire; Tianjin University; et al. (MDPI, 2021-08-26)
      Currently, global warming has been a serious issue, which is closely related to anthropogenic emission of Greenhouse Gas (GHG) in the atmosphere, particularly Carbon Dioxide (CO2). To help achieve carbon neutrality by decreasing CO2 emissions, Oxy-Fuel Combustion (OFC) technology is becoming a hot topic in recent years. However, few findings have been reported about the implementation of OFC in dual-injection Spark Ignition (SI) engines. This work numerically explores the effects of Water Injection (WI) strategies on OFC characteristics in a practical dual-injection engine, including GDI (only using GDI), P50-G50 (50% PFI and 50% GDI) and PFI (only using PFI). The findings will help build a conceptual and theoretical foundation for the implementation of OFC technology in dual-injection SI engines, as well as exploring a solution to increase engine efficiency. The results show that compared to Conventional Air Combustion (CAC), there is a significant increase in BSFC under OFC. Ignition delay (θF) is significantly prolonged, and the spark timing is obviously advanced. Combustion duration (θC) of PFI is a bit shorter than that of GDI and P50-G50. There is a small benefit to BSFC under a low water-fuel mass ratio (Rwf). However, with the further increase of Rwf from 0.2 to 0.9, there is an increment of 4.29%, 3.6% and 3.77% in BSFC for GDI, P50-G50 and PFI, respectively. As WI timing (tWI) postpones to around −30 °CA under the conditions of Rwf ≥ 0.8, BSFC has a sharp decrease of more than 6 g/kWh, and this decline is more evident under GDI injection strategy. The variation of maximum cylinder pressure (Pmax) and combustion phasing is less affected by WI temperature (TWI) compared to the effects of Rwf or tWI. BSFC just has a small decline with the increase of TWI from 298 K to 368 K regardless of the injection strategy. Consequently, appropriate WI strategies are beneficial to OFC combustion in a dual-injection SI engine, but the benefit in fuel economy is limited.
    • Electrical conductivity measurement of λ DNA molecules by conductive atomic force microscopy

      Wang, Ying; Xie, Ying; Gao, Mingyan; Zhang, Wenxiao; Liu, Lanjiao; Qu, Yingmin; Wang, Jiajia; Hu, Cuihua; Song, Zhengxun; Wang, Zuobin; et al. (IOP Publishing, 2021-11-08)
      Conductive atomic force microscopy (C-AFM) is a powerful tool used in the microelectronics analysis by applying a certain bias voltage between the conducting probe and the sample and obtaining the electrical information of sample. In this work, the surface morphological information and current images of the lambda DNA (λ DNA) molecules with different distributions were obtained by C-AFM. The 1 and 10 ng μl−1 DNA solutions were dripped onto mica sheets for making randomly distributed DNA and DNA network samples, and another 1 ng μl−1 DNA sample was placed in a DC electric field with a voltage of 2 V before being dried for stretching the DNA sample. The results show that the current flowing through DNA networks was significantly higher than the stretched and random distribution of DNA in the experiment. The I–V curve of DNA networks was obtained by changing the bias voltage of C-AFM from −9 to 9 V. The currents flowing through stretched DNA at different pH values were studied. When the pH was 7, the current was the smallest, and the current was gradually increased as the solution became acidic or alkaline.
    • Energy detection based spectrum sensing over two-wave and diffuse power fading channels

      Chatziantoniou, Eleftherios; Allen, Ben; Velisavljević, Vladan; Karadimas, Petros; Coon, Justin; University of Bedfordshire; Queens University Belfast; University of Oxford (IEEE, 2016-04-21)
      One of the most important factors that affects the performance of energy detection (ED) is the fading channel between the wireless nodes. This paper investigates the performance of ED-based spectrum sensing, for cognitive radio (CR), over two-wave with diffuse power (TWDP) fading channels. The TWDP fading model characterizes a variety of fading channels, including well-known canonical fading distributions, such as Rayleigh and Rician, as well as worse-than-Rayleigh fading conditions modeled by the two-ray fading model. Novel analytic expressions for the average probability of detection over TWDP fading that account for single-user and cooperative spectrum sensing and square law selection diversity reception are derived. These expressions are used to analyze the behavior of ED-based spectrum sensing over moderate, severe, and extreme fading conditions and to investigate the use of cooperation and diversity as a means of mitigating the fading effects. The obtained results indicate that TWDP fading conditions can significantly degrade sensing performance; however, it is shown that detection performance can be improved when cooperation and diversity are employed. The presented outcomes enable identifying the limits of ED-based spectrum sensing and quantifying the tradeoffs between detection performance and energy efficiency for CR systems deployed within confined environments, such as in-vehicular wireless networks.
    • Energy management in LTE networks

      Kanwal, Kapil; Safdar, Ghazanfar Ali; Ur-Rehman, Masood; Yang, Xiaodong; University of Bedfordshire (IEEE, 2017-03-28)
      Wireless cellular networks have seen dramatic growth in number of mobile users. As a result, data requirements, and hence the base-station power consumption has increased significantly. It in turn adds to the operational expenditures and also causes global warming. The base station power consumption in long-term evolution (LTE) has, therefore, become a major challenge for vendors to stay green and profitable in competitive cellular industry. It necessitates novel methods to devise energy efficient communication in LTE. Importance of the topic has attracted huge research interestsworldwide. Energy saving (ES) approaches proposed in the literature can be broadly classied in categories of energy efcient resource allocation, load balancing, carrier aggregation, and bandwidth expansion. Each of these methods has its own pros and cons leading to a tradeoff between ES and other performance metrics resulting into open research questions. This paper discusses various ES techniques for the LTE systems and critically analyses their usability through a comprehensive comparative study.
    • Experimental and numerical investigations into temperature distributions and VOC conversion rate of RTO

      Liu, Jingyin; Peng, Zhijun; Nantong University; University of Lincoln; University of Bedfordshire (IOP Publishing Ltd, 2022-01-07)
      As regulations for controlling VOCs (Volatile Organic Compounds) emissions have become more and more stringent, RTO (Regenerative Thermal Oxidizer) which involves heat exchange and storage, combustion and reaction processes has to be further optimised for enhancing the VOC treatment efficiency and reducing energy consumption. In this paper, influences of operating temperature distributions and internal flow fields on gas-out VOC concentration have been studied with experimental investigation and CFD numerical simulation. Experimental results shows that combustion temperature (around the combustor) plays more critical role than thermal storage bed temperature for affecting VOC flow-out concentration. By examining the internal flow and temperature distributions, modelling results demonstrate that fast heat transfer takes place in thermal ceramic beds and high temperature areas are formed around the combustor. At about 20 seconds after a bed working for gas-in flow, the heat transfer has demonstrated obvious attenuating. The research suggests that it is very challenging for simultaneously maintaining low gas-out VOC concentration and keeping low fuel consumption and low combustion temperature in RTOs.
    • Experimental investigation into the effect of magnetic fuel reforming on diesel combustion and emissions running on wheat germ and pine oil

      Thiyagarajan, S.; Herfatmanesh, Mohammad R.; Geo, V. Edwin; Peng, Zhijun; SRM University, India; University of Hertfordshire; University of Bedfordshire (Elsevier, 2019-01-11)
      The present study aims to explore the effect of fuel ionisation on engine performance, emission and combustion characteristics of a twin cylinder compression ignition (CI) engine running on biofuel. Wheat germ oil (WGO) and pine oil (PO) have been identified as diesel fuel surrogates with high and low viscosities, respectively. High viscosity biofuels result in incomplete combustion due to poor atomisation and vaporisation which ultimately leads to insufficient fuel and air mixing to form a combustible mixture. Consequently, engines running on this type of fuel suffer from lower brake thermal efficiency (BTE) and higher soot emissions. In contrast, low viscosity biofuels exhibit superior combustion characteristics however they have a low cetane number which causes longer ignition delay and therefore higher NO emission. To overcome the limitations of both fuels, a fuel ionisation filter (FIF) with a permanent magnet is installed before the fuel pump which electrochemically ionises the fuel molecules and aids in quick dispersion of the ions. The engine used in this investigation is a twin cylinder tractor engine that runs at a constant speed of 1500 rpm. The engine was initially run on diesel to warm-up before switching to WGO and PO, this was mainly due to poor cold start performance characteristics of both fuels. At 100% load, brake thermal efficiency (BTE) for WGO is reduced by 4% compared to diesel and improved by 7% with FIF. In contrast, BTE for PO is 4% higher compared to diesel, however, FIF has minimal effect on BTE when running on PO. Although, smoke, HC and CO emissions were higher for WGO compared to diesel, they were lower with FIF due to improved combustion. These emissions were consistently lower for PO due to superior combustion performance, mainly attributed to low viscosity of the fuel. However, NO emission for PO (1610 ppm) is higher compared to diesel (1580 ppm) at 100% load and reduced with FIF (1415 ppm). NO emission is reduced by approximately 12% for PO+FIF compared to PO. The results suggest that FIF has the potential to improve the combustion performance and reduce NO emission of high viscosity and low viscosity biofuels, respectively.
    • Exploring the potential benefits of Ethanol Direct Injection (EDI) timing and pressure on particulate emission characteristics in a Dual-Fuel Spark Ignition (DFSI) engine

      Li, Xiang; Li, Dayou; Liu, Jingyin; Ajmal, Tahmina; Aitouche, Abdel; Mobasheri, Raouf; Rybdylova, Oyuna; Pei, Yiqiang; Peng, Zhijun; ; et al. (Elsevier, 2022-04-26)
      Nowadays, particulate matter emitted by vehicles severely impacts environmental quality and human health. In this paper, the potential benefits of Ethanol Direct Injection (EDI) timing and pressure on particulate emission characteristics in a Dual-Fuel Spark Ignition (DFSI) engine were initially and systematically explored. The experimental results illustrate that by delaying EDI timing from -340 ºCA to -300 ºCA, there is a significant benefit in both particulate number and mass concentration. Furthermore, the size distribution curve of particulate number changes from bimodal to unimodal, meantime size distribution curves of particulate mass consistently concentrate on the accumulation mode. By increasing EDI pressure from 5.5 MPa to 18 MPa, the droplet size of ethanol spray can be effectively reduced. The benefit of increasing EDI pressure is more apparent in reducing particulate number is than particulate mass. The concentration of number and mass for total particulates have a reduction of 51.15% and 22.64%, respectively. In summary, it was demonstrated that an appropriate EDI timing or high EDI pressure could be a practical and efficient way to reduce particulate emissions in a DFSI engine.
    • Fabrication of hierarchical Ti6Al4V structures by hydrothermal treatment and laser interference lithography with enhanced ice resistance

      Liu, Ri; Wu, Xiaoming; Cao, Liang; Liu, Dongdong; Sun, Baishun; Weng, Zhankun; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2021-11-18)
      Icing widely exists in aerospace, transportation and electric power communication, causing great safety risks to people's production and life. Inhibiting icing is of great significance in practical engineering applications, and thus, employing an economical and efficient anti-icing method is a research hotspot. In this work, an anti-icing structured surface was fabricated by combining direct laser interference lithography (DLIL) with hydrothermal treatment. A micro-pillar array structure on the tc4 substrate was easily fabricated by DLIL, and a layer of nano-grass structure on the micro-pillar array was grown by hydrothermal treatment. These hierarchically textured surfaces exhibited low-temperature-adaptive water repellency (150° at −10°C, which delayed the frozen time (DT∼1h) and dropped frozen temperature. The above conditions were analyzed from the angle of wettability and heat conduction, and the influence of structure and wettability on ice resistance was discussed.
    • Fabrication of periodically micropatterned magnetite nanoparticles by laser-interference-controlled electrodeposition

      Wang, Lu; Dong, Litong; Li, Li; Weng, Zhankun; Xu, Hongmei; Yu, Miao; Wang, Zuobin; Changchun University of Science and Technology (Springer US, 2017-11-09)
      This paper introduces a laser-interference-controlled electrochemical deposition method for direct fabrication of periodically micropatterned magnetite (Fe3O4) nanoparticles (NPs). In this work, Fe3O4 NPs were controllably synthesized on the areas where the photoconductive electrode was exposed to the periodically patterned interferometric laser irradiation during the electrodeposition. Thus, the micropattern of Fe3O4 NPs was controlled by interferometric laser pattern, and the crystallization of the particles was controlled by laser interference intensity and electrochemical deposition conditions. The bottom-up electrochemical approach was combined with a top-down laser interference methodology. This maskless method allows for in situ fabrication of periodically patterned magnetite NPs on the microscale by electrodeposition under room temperature and atmospheric pressure conditions. In the experiment, Fe3O4 NPs with the mean grain size below 100 nm in the pattern of 5-lm line array were achieved within the deposition time of 100 s. The experiment results have shown that the proposed method is a one-step approach in fabricating large areas of periodically micropatterned magnetite NPs.
    • A feasibility study of implementation of oxy-fuel combustion on a practical diesel engine at the economical oxygen-fuel ratios by computer simulation

      Li, Xiang; Peng, Zhijun; Ajmal, Tahmina; Aitouche, Abdel; Mobasheri, Raouf; Pei, Yiqiang; Gao, Bo; Wellers, Matthias; University of Bedfordshire; Centre de Recherche en Informatique Signal et Automatique de Lille; et al. (SAGE Publications, 2020-12-09)
      To help achieve zero carbon emissions from inland waterway vessels, this implementation of oxy-fuel combustion on a practical diesel engine at the economical oxygen-fuel ratios were systematically studied and analysed in this paper. A 1-D simulation was used to explore the effect of various operating parameters for recovering the engine power when the engine is modified to the oxy-fuel combustion from conventional air combustion. The brake power of oxy-fuel combustion is only 26.7kW that has a noticeable decline compared with 40 kWof conventional air combustion with fixed consumption of fuel and oxygen. By optimising some valuable parameters, like fuel injection timing, intake charge temperature, intake components, engine compression ratio and water injection strategy, a benefit of 6.8kW has been acquired in the engine power. Afterwards, a remarkable benefit was obtained with the increase of lambdaO2 from 1.0 to 1.5, finally obtaining the same engine power with the conventional air combustion. Above all, taking advantage of various operating parameters, it is expected to further improve the value of the implement of oxy-fuel combustion on diesel engines at the economical oxygen-fuel ratios.
    • Fuzzy logic based intention recognition in STS processes

      Lu, Hang; Li, Dayou; Qiu, Renxi; University of Bedfordshire (Institute of Electrical and Electronics Engineers Inc., 2017-01-19)
      This paper represents a fuzzy logic based classifier that is able to recognise human users' intention of standing up from their behaviours in terms of the force they apply to the ground. The research reported focused on the selection of meaningful input data to the classifier and on the determination of fuzzy sets that best represent the intention information hidden in the force data. The classifier is a component of a robot chair which provides the users with assistance to stand up based on the recognised intention by the classifier.
    • Growth behavior of SHSY5Y cells on hybrid micro-pit and nano-pillar arrays

      Wu, Xiaomin; Li, Li; Liu, Ri; Weng, Zhankun; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2021-11-18)
      The directional arrangement and extension of cells is of great significance in the tissue engineering field. Great efforts have been made to study the effects of micro- or nano- structures on cell behaviors, but they are still poorly understood. In this work, hybrid micro/nano structures prepared by combining laser marking technology with metal assisted chemical etching (MACE) were introduced to study their effect on the growth behavior of SHSY5Y cells. It was found that the cells on the silicon micro-pit arrays (SiMP arrays, unetched substrate) were arranged orderly along the edge of the micro-pits, stretched and connected with each other, while the cells on the hybrid silicon micro-pit and silicon nano-pillar arrays (hybrid SiMP/SiNP arrays, etched substrates) were also arranged in an orderly manner with a relatively short cell stretch, but displayed a preference for independent growth. In addition, about 90% of cells showed a preference for growing on the area of nano-pillars (NPs), and only 10% of cells on the area of micro-pits (MPs) on the etched substrate. The results showed that the hybrid SiMP/SiNP arrays trapped cells and restricted the cell spreading. Thus, this approach is of great significance for the study of independent growth behavior of cells on the substrate in the field of single neuron research.
    • Highly birefringent nonlinear PCF for optical sensing of analytes in aqueous solutions

      Ademgil, Huseyin; Haxha, Shyqyri; European University of Lefke, Turkey; University of Bedfordshire (Elsevier, 2016-05-01)
      This paper presents a design of a nonlinear Photonic Crystal Fiber (PCF) based sensor exhibiting simultaneously high sensitivity, high birefringence and low confinement losses for liquid analyte sensing applications. We investigate the PCF sensor performance for the following analytes; Water, Ethanol and Benzyne. The impact of various design parameters of the highly nonlinear PCF on the relative sensitivity, the confinement losses and the birefringence features of the proposed PCF structure is numerically investigated by employing the full vectorial Finite Element Method (FEM). According to our FEM numerical results, a three ring nonlinear PCF based sensor is designed that simultaneously offers high birefringence of order 10-3 and high relative sensitivity at wide wavelength range.
    • A hybrid approach for image super-resolution of light field images

      Farag, Saber; Velisavljević, Vladan; Aggoun, Amar (IEEE, 2017-09-22)
      Recent advances in camera technologies has led to the design of plenoptic cameras. This camera type can capture multiple images of the same scene using arrays of microlenses, where each microlens has a shifted location providing a separate view of the scene. Such a design results in a superior performance as compared to traditional cameras, enabling multi-view or multi-focal imaging captured in a single shot. However, currently available plenoptic cameras are limited in spatial resolution, which makes it difficult to use them in applications where sharpness or high resolution is key, such as the film industry. Our paper presents a novel light field hybrid super-resolution method that combines two classical super-resolution techniques for efficient application to plenoptic images. After this combination, we first segment the output hybrid super-resolution image into the objects of interest. Afterward, we apply sparse representation to super resolve the segmented image. This technique helps to improve the quality by decrease computations for light field images and extract significant features from the objects of interest. We demonstrate the gain achieved by the novel method as compared to the current relevant approaches in terms of both PSNR and SSIM for various enhanced spatial resolutions.
    • Implantable antennas for bio-medical applications

      Malik, Nabeel A.; Sant, Paul; Ajmal, Tahmina; Ur-Rehman, Masood; University of Bedfordshire; University of Glasgow (Institute of Electrical and Electronics Engineers Inc., 2020-10-08)
      Biomedical telemetry has gained a lot of attention with the development in the healthcare industry. This technology has made it feasible to monitor the physiological signs of patient remotely without traditional hospital appointments and follow up routine check-ups. Implantable Medical Devices(IMDs) play an important role to monitor the patients through wireless telemetry. IMDs consist of nodes and implantable sensors in which antenna is a major component. The implantable sensors suffer a lot of limitations. Various factors need to be considered for the implantable sensors such as miniaturization, patient safety, bio-compatibility, low power consumption, lower frequency band of operation and dual-band operation to have a robust and continuous operation. The selection of the antenna is a challenging task in implantable sensor design as it dictates performance of the whole implant. In this paper a critical review on implantable antennas for biomedical applications is presented.