Clays have traditionally been linked to health care, being used for centuries in the fight against infections and diseases. Similarly, biohybrids produced by combinations of clays and biological species through ‘bottom-up’ approaches have been evaluated over the past decade for biomedical and pharmaceutical uses. These biohybrids show interesting features such as biocompatibility and biodegradability which make them suitable for healthcare applications. The aim of the present communication was to review recent research contributions describing progress and the role of biohybrid materials based on clays in biomedicine and pharmacy disciplines. Emphasis will be on the authors’ own experience of this topic, particularly on aspects related to controlled drug-delivery systems, adjuvants of vaccines, and vectors for non-viral gene transfection. Bionanocomposites offer several advantages for use in the design of new and efficient pharmacological formulations for cutaneous and oral administration. In these systems, the drug is typically entrapped in the clay and protected by a biopolymer matrix, and both components contribute to a gradual release of the drug. Clay-based hybrids have also shown their efficacy in vaccines as they can act as nanocarriers of viral particles, due to the biomimetic interface created on the clay surface after adsorption of suitable biomolecules such as phospholipids, while the clay acts as an adjuvant to increase the efficacy of the vaccine. Finally, a new application of clays as non-viral vectors for controlled gene delivery is attracting increasing interest in the treatment of diverse diseases; clays such as sepiolite have demonstrated their ability to act as nanocarriers of nucleic acids and facilitate their transfection in mammalian cells.

Focus here is placed on the pharmaceutical and biomedical applications of novel clay-drug hybrid materials categorized by methods of administration. Clay minerals have been used for many years as pharmaceutical and medicinal ingredients for therapeutic purposes. A number of studies have attempted to explore clay-drug hybrid materials for biomedical applications with desired functions, such as sustained release, increased solubility, enhanced adsorption, mucoadhesion, biocompatibility, targeting, etc. The present review attempts not only to summarize the state-of-the-art of clay-drug hybrid materials and their advantages, depending on the methods of administration, but also to deal with challenges and future perspectives of clay mineral-based hybrids for biomedical applications.

A rectangular monopole antenna with an extended ground, excited by Coplanar Waveguide (CPW) and backed by a 6 × 6 array of fractal artificial magnetic conductor (AMC) unit cells, resonating at 5.8 GHz in Industrial, Scientific, and Medical (ISM) band, is presented in this manuscript. To attain the objective of proposing a compact and economical antenna solution for employment in wearable biomedical domain, a novel approach of utilizing both surfaces of the same dielectric for engraving antenna element as well as AMC array is adopted. It results in the elimination of layers of expensive substrate (RO3003) and of thick separator (foam) between antenna and AMC array. During measurement in open space, the proposed antenna system exhibited an impedance bandwidth of 570 MHz with a gain of 7.9 dBi. While a total realized gain of 7.5 dBi, amounting to a gain enhancement of about 3 dB as compared to that of monopole alone, is observed when the integrated antenna system is placed just over a three-layer rectangular human body equivalent model. Specific absorption rate values, as calculated at 5.8 GHz and averaged over 1 and 10 g of human tissue, are 0.0117 and 0.00244 W/kg, respectively. Obtained results strongly advocate the use of the proposed antenna system in smart wearable healthcare devices.

Shape memory polymers (SMPs) are a type of programmable materials capable of transforming their shapes in a pre-programmed way upon the application of an external stimulus. These materials have been tested for various potential applications particularly in the biomedical field for polymers with general and specific requirements. This review focuses on the recent advances in biomedical applications, including self-tightening sutures, pressure bandages, self-expansion stents, tissue engineering scaffolds, artificial muscles, drug delivery, and orthodontic archwires, after a brief description of the concepts, classifications, programming procedures, and material requirements of SMPs.

Telemetry acquisition from rodents is important in biomedical research, where rodent behavior data is used to study disease models. Telemetry devices for such data acquisition require a long-term powering method. Wireless power transfer (WPT) via magnetic resonant coupling can provide continuous power to multiple small telemetric devices. Our loosely coupled WPT (LCWPT) system consists of a stationary primary coil and multiple freely moving secondary coils. Our previous LCWPT system was designed to transfer reasonable power to secondary coils at poor orientations but transfers excessively high amounts of power at favorable orientations. Reasonable power is needed for telemetry and radio electronics, but highly induced voltage on the secondary coil creates excess energy which must be dissipated by previous devices, and caused problems (localized heat damage and variations in component properties) leading to drift in operating frequency. To remedy these two problems, a novel scheme is proposed to automatically tune or detune the resonant frequency of the secondary circuit. Our closed-loop controlled tuning or detuning (CTD) approach can be used to prevent excessive power transfer by detuning, or to improve power transfer by tuning, depending on the need. Furthermore, this novel CTD scheme facilitates the use of multiple telemetric devices.

Radiofrequency surface coils used as receivers in magnetic resonance imaging (MRI) rely on cables for communication and power from the MRI system. Complex surface coil arrays are being designed for improving acquisition speed and signal-to-noise ratio. This, in-turn makes the cables bulky, expensive, and the currents induced on cables by time-varying magnetic fields of the MRI system may cause patient harm. Though wireless power transfer (WPT) can eliminate cables and make surface coils safer, MRI poses a challenging electromagnetic environment for WPT antennas because the antennas made using long conductors interact with the static and dynamic fields of the MRI system. This paper analyses the electromagnetic compatibility of WPT antennas and reveals that commercially available antennas are not compatible with MRI systems, presenting a safety risk for patients. Even when the risk is minimized, the antennas couple with surface coils leading to misdiagnosis. This paper presents an approach to eliminate safety risks and minimize coupling using a filter named “floating filter.” A WPT antenna without a filter has a distortion of 27%, and floating filters reduce the distortion to 2.3%. Secondly, the floating filter does not affect the power transfer efficiency, and the transfer efficiency of 60% is measured with and without filters.

A planar inverted F-Antenna with the dual band-dual polarization property is presented for medical body area networks applications. The designed antenna covers the 2.45 GHz industrial, scientific and medical, 4 G long term evolution (2.5–2.69 GHz) bands for ON body communication and Wi-Fi and WLAN (3.5–3.6 GHz) bands for OFF body communication. At the lower band, an equivalent offset fed magnetic microstrip type dipole has been utilized that generate field parallel to the surface of the body for supporting ON body communication. The broadside radiation pattern has been realized using the slotted patch counterpart for supporting OFF body communication. This technique has resulted in a design of dual band dual mode property using a single radiator. The footprint of the antenna is only 0.35λg × 0.17λg × 0.08λg. Owing to its compactness, lightweight, and easy mountable property (due to foam substrate), the proposed antenna is found to be robust for MBAN applications. The maximum permissible transmitted power for the 1st band is 25.78 and 20.3 dBm for the 2nd one to maintain standard specific absorption rate limitations of 1.6 W/Kg. Experimental investigations over human body showed minimal deviations from the free space conditions which makes it a potential candidate for body-centric communications.

Medical imaging is of great importance for patients affected by stroke. Since an early examination of the patient is necessary for successful recovery, there is room to improve the existing capabilities of analysis. Common systems like magnetic resonance imaging or computed tomography are precise, but stationary, and therefore, not ideally suited for the early analysis of stroke. The presented multiport vector network analyzer system uses electromagnetic tomography (EMT) as an alternative imaging technique. It consists of a network of distributed electronic sensor nodes which improve important parameters: the parallel measurement setup reduces the measurement time as low as 160 ms for a 200-port S-parameter matrix and it is capable of measuring signal levels down to − 150 dBm. The electronics allow a compact, movable packaging, leading the way for future portable devices. The detection of stroke models was examined by test measurements of a phantom. The data was analyzed by the help of an inverse reconstruction algorithm. The possibility of building portable setups which can be even applied to patients inside an ambulance, makes EMT a suitable alternative for early stroke detection. It can help in shortening the recovery of patients, by providing an early analysis of the brain.

A novel compact directional antenna with improved gain is proposed for microwave breast imaging (MBI) applications. The radiating fins are modified by etching several slots to make the antenna compact and enhance antenna performance in terms of bandwidth, gain, efficiency, and directivity. Several parameters are studied and optimized to frequency from 3.1 to 6.5 GHz, which is typically used in the breast imaging system. The electrical length of the antenna is 0.39λ × 0.46λ × 0.01λ at the lower frequency band. The result shows that the antenna exhibits −10 dB impedance bandwidth of 4.3 GHz (2.7–7 GHz) with directional radiation pattern. The peak gain of the proposed prototype is 7.8 dBi and fractional bandwidth is 92%. The time domain results show that the fidelity factor for face to face is 0.92 and for side by side is 0.62, which prove the directivity and lower distortion of the signal. The proposed prototype is successfully simulated, fabricated, and measured.

This paper reports on a microwave heater at 20 GHz for digital microfluidics. It allows rapid heating of nanoliter fluid samples and simultaneous temperature monitoring by correlating the reflection coefficient of the heater with the temperature dependency of the relative permittivity of the lossy fluid under consideration, in this case demineralized water. Microwave heating was performed with power levels of 20 and 23 dBm at the on-wafer probe tips on samples of 500 nL. Temperature measurements were carried out with a miniaturized type K thermocouple, and a platinum resistor to monitor the reference temperature. Microwave and thermal performances have been characterized using multi-physics software, and measurements obtained with a large signal vector network analyzer showed good agreement with simulated data. An average heating rate of 20 °C/s was observed during the first 4 s of the heating process.

A novel transmission line structure has been developed to facilitate the delivery of both adrenaline and microwave energy to achieve hemostasis. A proximal end impedance transformer and radiative tip have been designed and manufactured to provide good match between the novel hollow transmission line and the microwave source and tissue, respectively. Further consideration of the challenges and problems encountered along with evidence of successful microwave energy delivery at 5.8 GHz into porcine liver model providing a controlled and focused coagulation zone of approximately 5 mm.

Continuous-wave (CW) radars have been recently investigated in healthcare aiming at contactless health monitoring. However, a major problem in monostatic CW architectures is represented by the unwanted leakage produced by poor isolation between transmitter and receiver, which can drastically decrease the receiver's sensitivity reducing therefore the radar dynamic range. Although this situation can be easily controlled in case of narrowband CW radar by an appropriate passive microwave design, it becomes much more complicated in case of stepped-frequency CW and frequency-modulated CW architectures that present an ultra-wideband nature. In this paper, a monostatic CW radar integrating a tunable wideband leakage canceler aiming at indoor tagless localization is presented and discussed. The use of the feedforward canceler allows a strong reduction of the unwanted leakage over the whole radar bandwidth. Experimental results demonstrate the feasibility of this approach, showing an outstanding improvement of the radar dynamic range.

This paper deals with the concept of microliter sensing of human blood samples by waveguide dielectrometry at microwave frequency (39.5 GHz). The methods, research protocol, and basic results derived from the permittivity measurements are presented. Here we summarize the results of our 5-year research on developing a multidisciplinary approach to the characterization of erythrocytes dielectric response, in parallel with biochemical studies of their receptor-membrane activity, within the scope of a case–control study for in vitro diagnostics of acute and chronic neurological conditions.

A 0.18 µm CMOS Binary Frequency Shift Keying Modulator with a novel frequency synthesizer structure is proposed in this paper. Based on an analog adder technique being the backbone of the synthesizer, this prototype demonstrates a compact modulator with low complexity, which achieves 1 Mbps at 400 MHz while dissipating 3.1 mW at 1.5 V supply. The proposed design is ideal for biomedical sensor network systems including distributed wearable body area network.

A novel coplanar waveguide-fed Z-monopole antennas are proposed for the first time for a industrial, scientific, and medical (ISM) band (2.4–2.48 GHz) applications. To make the designed antenna suitable for implantation, it is embedded in biocompatible Al2O3 ceramic substrate. The antenna operates at resonance frequency of 2.45 GHz to support wide band communication for high data rate implantable neural monitoring application. The size of the antenna is 38.675 mm3 (8.5 mm × 7 mm × 0.65 mm). The antenna was simulated and measured by immersing it in a phantom liquid, imitate the electrical properties of the human body phantom liquid. The simulated and measured bandwidths are 10.2 and 11.4% at the centre frequency. A study of the sensitivity of the antenna performance as a function of its dielectric parameters of the environment in which it is immersed was performed. The demonstration among the design EM characteristics of the antenna is presented by current distributions.

Implantable antennas have recently been receiving substantial attention for medical diagnosis and treatment. In this paper, a coplanar waveguide-fed monopole antenna for industrial, scientific, and medical (ISM) band biomedical applications is proposed. The antenna has a simple structure is placed on human tissues such as muscle, fat, and skin. The designed antenna is made compatible for implantation by embedding it in an FR4 substrate. The proposed antenna is simulated using the method of moment's software IE3D by assuming the predetermined dielectric constant for the human muscle tissue, fat, and skin. The antenna operates in the frequency of ISM bands, 2.4–2.48 GHz. Simulated and measured gains attain −7.7 and −8 dBi in the frequency of 2.45 GHz. The radiation pattern, return loss, current distribution, and gain of these antennas were examined and characterized.

A novel coplanar waveguide fed Industrial, Scientific, and Medical (ISM) band implantable crossed-type triangular slot antenna is proposed for biomedical applications. The antenna operates at the center frequency of 2450 MHz, which is in ISM band, to support GHz wideband communication for high-data rate implantable biomedical application. The size of the antenna is 78 mm3 (10 mm × 12 mm × 0.65 mm). The simulated and measured bandwidths are 7.9 and 8.2% at the resonant frequency of 2.45 GHz. The specific absorption rate distribution induced by the implantable antenna inside a human body tissue model is evaluated. The communication between the implanted antenna and external device is also examined. The proposed antenna has substantial merits such as miniaturization, lower return loss, better impedance matching, and high gain over other implanted antennas.

The establishment of food preferences and aversions determines the modulation of eating behaviour and the optimization of food intake. These phenomena rely on the learning and memory abilities of the organism and depend on different psychobiological mechanisms such as associative conditionings and sociocultural influences. After summarizing the various behavioural and environmental determinants of the establishment of food preferences and aversions, this paper describes several issues encountered in human nutrition when preferences and aversions become detrimental to health: development of eating disorders and obesity, aversions and anorexia in chemotherapy-treated or elderly patients and poor palatability of medical substances and drugs. Most of the relevant biomedical research has been performed in rodent models, although this approach has severe limitations, especially in the nutritional field. Consequently, the final aim of this paper is to discuss the use of the pig model to investigate the behavioural and neurophysiological mechanisms underlying the establishment of food preferences and aversions by reviewing the literature supporting analogies at multiple levels (general physiology and anatomy, sensory sensitivity, digestive function, cognitive abilities, brain features) between pigs and humans.