This study presents a novel measurement system for monitoring the temperature of normal tissue during radiofrequency ablation (RFA), a critical challenge in cancer therapy. By utilizing laser beam deflection in response to temperature variations, we have proposed a sensing platform that incorporates various Au nanostructures on a glass plate as a sensing agent. The plasmon resonance behavior of these Au nanostructures is leveraged to enhance temperature sensitivity. We compared three types of nanostructures-Au nanoparticles, Au-SiO2 coreshell structures, and Au-SiO2-Au nanomatryoshkas-to identify the optimal configuration for precise, in situ, and quasi-real-time monitoring of surrounding healthy tissue during RFA. The results demonstrate that the AuSiO2-Au nanomatryoshka is the best Au nanostructure for this sensing platform, as it causes the greatest changes in laser beam deflection and exhibits significant variations in absorption based on temperature and wavelength. Our findings highlight the potential of this system to significantly improve patient safety by enabling effective temperature management during treatment.

The thermal conductivity of a biological tissue, which depends on the tissue's molecular structure, provides crucial insights into its physiological function. Furthermore, various medical diagnostic and therapeutic strategies are based on the tissue's thermal properties. Here, we have employed the photothermal shadowgraph technique, an optical method to measure the tissue's thermal conductivity and diffusivity. In this regard, five distinct tissues extracted from three Naval Medical Research Institute (NMRI) male mice were examined. We investigated the quantitative impact of different nanoparticles (NPs) present within the tissues on the thermal conductivity. The findings reveal a strong agreement between the measured values of the thermal conductivity and diffusivity obtained through the photothermal shadowgraph technique and those obtained using other methods. Additionally, the results indicate that Au, ZnO, and CaCO3 significantly enhance the thermal conductivity of the tissues by 4, 2, and 2 times, respectively. The TiO2 and Al2O3 exhibited no discernible impact on the thermal conductivity of the tissue. Consequently, we can infer that the photothermal shadowgraph technique offers a contactless, quick, precise, and accurate method for determining the thermal properties of samples from biological tissues obviating the need for complicated instrumentations or a specific sample preparation procedure.

Chronic wound healing is often a prolonged process with the migration and proliferation of fibroblast cells playing crucial roles. Electrical stimulation (ES) has emerged as a promising physical therapy modality to promote these key events. In this study, we address this issue by employing a triboelectric nanogenerator (TENG) as an electrical stimulator for both drug release and the stimulation of fibroblast cells. The flexible TENG with a sandwich structure was fabricated using a PCL nanofibrous layer, Kapton, and silicon rubber. The TENG could be folded to any degree and twisted, and it could return to its original shape when the force was removed. Cultured cells received ES twice and three times daily for 8 days, with a 30 min interval between sessions. By applying current in a safe range and appropriate time (twice daily), fibroblasts demonstrate an accelerated proliferation and migration rate. These observations were confirmed through cell staining. Additionally, in vitro tests demonstrated the TENG's ability to simultaneously provide ES and release vitamin C from the patch. After 2 h, the amount of released drug increased 2 times in comparison to the control group. These findings provide support for the development of a TENG for the treatment of wounds, which underlines the promise of this new technique for developing portable electric stimulation devices.

The growing demand for efficient and biocompatible materials in laser-induced medical hyperthermia applications has led us to investigate a novel material known as the gold nanomatryoshka. This unique structure, composed of three superimposed layers (Au-SiO2-Au), offers significant advantages over conventional plasmonic structures, such as gold nanorods, due to its spherical geometry and potential for achieving the highest available density. In this study, our primary motivation is to explore the tunable optical absorption properties of the gold nanomatryoshka by adjusting the core radius and the thickness of its two outer layers (shells). By applying the Mie theory to calculate the interaction of light with gold nanomatryoshka, the absorption and scattering cross sections of these structures were obtained. Additionally, by employing the Monte Carlo method (photon trans-port within biological tissue) and combining with the bioheat equation (thermal analysis in the tissue), the temperature distribution inside the tissue was obtained. The key aim of our research is to establish a robust computational modeling methodology for assessing the size-dependent efficiency of the gold nanomatryoshka in medical hyperthermia applications. The tunability of its optical properties, enabled by its unique structure, holds immense promise for optimizing its performance in laser-based cancer treatments and other biomedical applications. Present study concludes with the successful demonstration of the gold nanomatryoshka's potential for enhancing the effectiveness of laser-based cancer treatment. Furthermore, its biocompatibility, attributed to the outer gold layer, makes it a compelling candidate for treatment, particularly in nanoparticle-based treatments of cancer within organs like the prostate. The significance of this research lies in its contributions to the design and implementation of the gold nanomatryoshka in medical hyperthermia applications. By addressing concerns related to core-shell structures (Au-SiO2), our findings pave the way for developing more effective and targeted therapeutic strategies, thus advancing the field of laser-induced medical hyperthermia and its applications in cancer treatment.

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The use of nanoparticles, as enhancing agents to transform ultrasound energy into heat for tumor destruction, is a promising approach to improve the efficacy of thermal-based cancer therapies. This study aimed to evaluate the effectiveness of core-shell type nanoparticles and the heat loss due to blood flow in large vessels under different patterns of ultrasound sonication in the hyperthermia-based treatment of the prostate cancer. For this purpose, the ultrasound attenuation coefficient in the prostate tumor embedded with nanoparticles was calculated using a scattering theory that was developed for core-shell type particles. Using the attenuation coefficient and the linear pressure wave equation, the acoustic power dissipated per unit volume of a three-dimensional (3D) model of the prostate tumor and its surrounding tissues was calculated. By simultaneous solving the bioheat, the convective energy, the continuity, the Navier-Stokes, and the thermal dose equations, the temperature and thermal dose distribution were computed in the model. The attenuation coefficient of the tumor showed a decreasing trend with increasing the thickness of the silica shell coating the magnetite or titania core. The capability of nanoparticles to enhance heat production in the medium was directly, and the blood flow heat loss was inversely, related to the degree of focus of the ultrasound beam. The thermal response of the tumor was influenced by its size and geometry, as well as the acoustic intensity. Titania nanoparticles were more efficient than the magnetite nanoparticles in ultrasound attenuation and heat production in the medium. Our findings can be useful in understanding the factors affecting the hyperthermia-based treatment of the prostate cancer using a combination of ultrasound and nanoparticles.

The nature of intermolecular forces within semiconductor quantum dot systems can determine various physicochemical properties, as well as their functions, in nanomedical applications. The purpose of this study has been to investigate the nature of the intermolecular forces operating between Al2@C24 and Al2@Mg12O12 semiconducting quantum dots and the glycine tripeptide (GlyGlyGly), and also consider whether permanent electric dipole-dipole interactions play a significant role vis-à-vis these molecular systems. The energy computations, including the Keesom and the total electronic interactions and the energy decomposition, together with the quantum topology analyses were performed. Our results demonstrate that no significant correlation is found between the magnitude and orientation of the electrical dipole moments, and the interaction energy of the Al2@C24 and Al2@Mg12O12 with GlyGlyGly tripeptide. The Pearson correlation coefficient test revealed a very weak correlation between the quantum and the Keesom interaction energies. Apart from the quantum topology analyses, the energy decomposition consideration confirmed that the dominant share of the interaction energies was associated with the electrostatic interactions, yet both the steric and the quantum effects also made appreciable contributions. We conclude that, beside the electrical dipole-dipole interactions, other prominent intermolecular forces, such as the polarization attraction, the hydrogen bond, and the van der Waals interactions can also influence the interaction energy of the system. The findings of this study can be utilized in several areas in the field of nanobiomedicine, including the rational design of cell-penetrating and intracellular drug delivery systems using semiconducting quantum dots functionalized with a peptide.

In the present study, a new approach was introduced regarding the extracellular synthesis of selenium sulfide micro/nano-particles using Saccharomyces cerevisiae in different ammonium sulfate supplementation and in the presence of sodium selenosulfate precursors (S 1 ) and a blend of selenous acid and sodium sulfite (S 2 ). In S 1 , only cell supernatant exposed to ammonium sulfate was able to reduce sodium selenosulfate. Whereas, in S 2 , cell supernatant in both pre-conditions of with or without ammonium sulfate (S 2 + or S 2 −) were able to reduce selenous acid and sodium sulfite. Electron microscopy, also indicated that selenium sulfide NPs were successfully synthesized with average size of 288 and 332 nm for S 2 + and S 2 − in SEM and 268 and 305 nm in TEM. Additionally, elemental mapping by energy-dispersive x-ray analysis confirmed the presence of sulfur/selenium elements in the particles in a proportion of 24.50 and 23.31 for S 2 − and S 2 + , respectively. The mass spectrometry indicated the probability of Se 2 S 2 , SeS 1.1 , Se 2 , Se, SeS 5 , SeS 3 , Se 3 S 5 /Se 5 , Se 3 /SeS 5 , Se 6 , Se 4 /SeS 7 , Se 2.57 S 5.43 /Se 2 S 2 and Se 4 S/Se 2 S 6 molecules for S 2 + and of Se, Se 2 , Se 3 S 5 /Se 5 , Se 6 and Se 4 species for S 2 −. In FTIR spectra, primary (i.e. 1090–1020 and 1650–1580 cm −1 ) and secondary (1580–1490 cm −1 ) amine bands duly confirmed the protein corona around the NPs.

The electromechanical properties of the membrane of endothelial cells forming the blood-brain barrier play a vital role in the function of this barrier. The mechanical effect exerted by external electric fields on the membrane could change its electrical properties. In this study the effect of extremely low frequency (ELF) external electric fields on the electrical activity of these cells has been studied by considering the mechanical effect of these fields on the capacitance of the membrane. The effect of time-dependent capacitance of the membrane is incorporated in the current components of the parallel conductance model for the electrical activity of the cells. The results show that the application of ELF electric fields induces hyperpolarization, having an indirect effect on the release of nitric oxide from the endothelial cell and the polymerization of actin filaments. Accordingly, this could play an important role in the permeability of the barrier. Our finding can have possible consequences in the field of drug delivery into the central nervous system.

Skin wounds are common in accidental injuries, surgical operations, and chronic diseases. The migration and proliferation of fibroblast cells are fundamental to wound healing, which can be promoted by electrical stimulation as a physical therapy modality. Therefore, the development of portable electrical stimulation devices that can be used by patients on-site is an essential need. In the present study, a self-cleaning triboelectric nanogenerator (TENG) has been fabricated for enhancing cell proliferation and migration. The polycaprolactone‑titanium dioxide (PCL/TiO2) and polydimethylsiloxane (PDMS) layers were fabricated via a facile method and used as the electropositive and electronegative pair, respectively. The effect of stimulation time on proliferation and migration of fibroblast cells was investigated. The results demonstrated that when the cells were stimulated once-a-day for 40 min, the cell viability was increased, while a long daily stimulation time has an inhibitory effect. Under electrical stimulation, the cells move toward the middle of the scratch, making the scratch almost invisible. During repeated movements, the prepared TENG connected to a rat skin generated an open-circuit voltage and a short-circuit current around 4 V and 0.2 μA, respectively. The proposed self-powered device can pave the way for a promising therapeutic strategy for patients with chronic wounds.

BACKGROUND AND OBJECTIVE:It is known that the disintegration of microtubules in neurons occurs in response to the phosphorylation of the tau proteins that promotes the structural instability of the microtubules, as one of the factors underlying the onset of Alzheimer's disease (AD). METHODS:In this study, the mechanical variations undergone by the tau protein's and microtubule's structures due to the action of intrinsic magnetite nanoparticles inside the brain tissue have been computationally modeled using the finite element (FEM) method. RESULTS:The von Mises stress induced by magnetite nanoparticles, subject to an applied alternating magnetic field, leads to local heating and mechanical forces, prompting a corresponding deformation in, and displacement of, the microtubule and the tau protein. CONCLUSIONS:The induction of these deformations would increase the probability of the microtubules' depolymerization, and hence their eventual structural disintegration.

The widespread use of magnetite nanoparticles inside the bloodstream for diagnostic and therapeutic purposes has made the influence of the interaction forces between these nanoparticles an important issue for predicting their behavior for improving the effectiveness of the protocols. Magnets with various geometries have been used in different biomedical applications, such as targeted drug delivery, to guide drugs carrying magnetite nanoparticles to specific areas. In this regard, using computational modeling, we have employed a multiphysics modeling approach using the particle tracing module in the COMSOL software environment to investigate the behavior of magnetite nanoparticles considering not only the magnetophoretic force, but also the dipole–dipole interaction forces between the nanoparticles. The effects of different geometries of magnets on the induced magnetic flux density and the laminar flow velocity inside the bloodstream were studied as well. The results of our study show that each geometry of the magnet induces different magnetic flux density profile and laminar velocity inside the blood flow. The behavior of ferrofluid flow is dependent on the geometry of the magnet and its remanent flux density. By increasing the size of magnetic nanoparticles, the magnetophoretic force enhances the particle velocity in the direction perpendicular to the vessel's walls, which could result in pull out. The results also reveal that the magnetic dipole–dipole interactions between nanoparticles could lead to the induction of higher dipole–dipole interaction forces in regions close to the magnet, especially on the upper wall of the blood vessel.

It is an established paradigm in the emerging fields of nanoscience, nanotechnology and molecular engineering that a very important domain of fundamental research is associated with carbon-based materials. Ever since the discovery of the first member of the fullerene family (C60) in 1985, and the subsequent discovery of the other members, fullerenes as a nanoscopic allotrope of carbon with anticipated extensive applications in all areas of nanoscience and nanotechnology (both industrial and medical), materials science and engineering, condensed matter physics and chemistry have occupied a central position in research activities across the globe. Detailed investigations, both experimental and theoretical/computational, into their morphology, mechanical, thermal, chemical, biological, electronic, optical and structural properties have led to the emergence of a well-established and independent science of fullerenes, providing very valuable information both in basic and applied sciences. A comprehensive review of these properties of fullerenes, particularly their applications in the above fields will provide valuable up-to-date and essential background information for engaging in new research in this field and also be able to develop new concepts and applications of these exotic carbon structures. For instance, a recent development is their applications in the emerging field of nanoneuroscience, a field interfacing nanoscience and neuroscience. In this extensive, albeit selective survey, related mainly to the C60 fullerenes, the processes involving their experimental synthesis, theoretical formulation of their geometrical structures, their mechanical and thermal properties and nanomedical applications have been reviewed and summarized both within the experimental and theoretical/computational domains. Essential theoretical concepts, ranging from discrete atomistic molecular dynamics and molecular mechanics methods to continuum-based methods have been expounded in order to facilitate the pursuance of the reviewed literature and also to aid in the development of further research in this field.

Neurological disorders and nerve injuries, such as spinal cord injury, stroke, and multiple sclerosis can result in the loss of muscle function. Electrical stimulation of the neuronal cells is the currently available clinical treatment in this regard. As an effective energy harvester, the triboelectric nanogenerators (TENG) can be used for self-powered neural/muscle stimulations because the output of the TENG provides stimulation pulses for nerves. In the present study, using a computational modelling approach, the effect of surface micropatterns on the electric field distribution, induced voltage and capacitance of the TENG structures have been investigated. By incorporating the effect of the TENG inside the mathematical model of neuron’s electrical behavior (cable equation with Hodgkin-Huxley model), its impact on the electrical behavior of the neurons has been studied. The results show that the TENG operates differently with various surface modifications. The performance of the TENG in excitation of neurons depends on the contact and release speed of its electrodes accordingly.

The tripeptide Arg-Gly-Asp acid (RGD) is a protein sequence in the binding of proteins to cell surfaces, and is involved in various biological processes such as cell adhesion to the extracellular matrix, platelet activation, hemostasis, etc. The C2 domain of the Von Willebrand Factor (VWF), containing the RGD motif, plays an important role in the initial homeostasis process. It binds to the aIIbb3 integrin and stimulates platelet aggregation. We have investigated, using the molecular Dynamic (MD) simulation method, the effect of the RGD-peptide length, and temperature variation, on the binding to the aIIbb3 integrin receptor. We examined 10 different structural modes of the aIIbb3 at three different temperatures; 237 K, 310 K and 318 K. Our findings show that the amino acids that form a binding pocket include Asp224, Tyr234, Ser226, Tyr190, Tyr189, Trp260, Trp262, Asp259, Lys253, Arg214, Asp217, Ser161 and Ala218 and that the ligand-receptor interaction was increased at higher temperatures. It was also found that the increase in the number of ligands' amino acids and their types (% glycine) plays an important role in the stability, conformation, and ligand-receptor interaction.

Considering the severe hazards of abnormal concentration level of H2S as an extremely toxic gas to the human body and due to the disability of olfactory system in sensing toxic level of H2S concentration, a reliable, sensitive, selective and rapid method for the detection of H2S is proposed and its efficacy is analyzed through simulation. The proposed system is based on the deflection of a laser beam in response to the temperature variations in its path. In order to provide selectivity and improve sensitivity, gold nanostructures were employed in the system. The selectivity was introduced based on the thiol-gold interactions and the sensitivity of the system was enhanced due to the modification of plasmon resonance behavior of gold nanostructures in response to gas adsorption. Results from our analysis demonstrate that compared with Au and SiO2-Au, the Au nanomatryoshka structures (Au-SiO2-Au) showed the highest sensitivity due to promoting higher deflections of the laser beam.

In view of efficiency, simple operation, and affordable cost and disposability, quartz tuning fork systems form good candidates for mechanical-based biosensors in point of care applications. Based on the geometrical structure, the frequency response of the tuning fork- based sensors is dependent on the location of absorbed samples. In order to have the maximum efficiency and sensitivity, the optimized condition of sample loading on the fork structures should be considered. In this regard, here, we have determined the optimized sample location to be on the prongs of the quartz tuning fork by calculating the frequency response of the quartz tuning fork using the finite element method. From an application point of view, we have obtained an agreement between the calculational method and the experimental excitation technique of the structure. The results from our study show that by using an appropriate location for the sample, the quartz tuning fork could be exploited with high sensitivity.

In this paper, we formulate an efficient continuum mechanics-based model on the basis of a discrete lattice model. First, the dispersion relation of a lattice wave in a one-dimensional diatomic crystal lattice is derived. Then, the second- and fourth-order continuum models are obtained from the differential difference equations of motion by using the Pade approximations. The results show that the proposed fourth-order continuum model can predict the dispersion behaviour of the one-dimensional diatomic crystal lattice very well in the first Brillouin zone. Furthermore, the applicability of the present model to the prediction of the dispersion behaviour of the one-dimensional diatomic lattice with internal resonator and inerter is examined. Finally, the vibration frequencies of finite diatomic lattices are calculated by both the discrete and the proposed continuum models. (C) 2019 Elsevier Ltd. All rights reserved.

Considering electronic skin applications, a pressure sensor based on periodic structure of graphene oxide-reduced graphene oxide (GO-rGO) has been designed and fabricated based on a low cost direct laser writing technique by utilizing the laser diode of DVD drive's pickup head. The optimization of sensor structure has been performed using computational modelling through Finite Element Method (FEM) in the COMSOL environment. The optimized structure is fabricated based on the deposition of thin layer of GO on the surface of Kapton and the pattering is performed by laser irradiation. The fabricated sensor structure has been characterized structurally and functionally. The results show that the fabrication method is successful in the formation of periodic structure of GO-rGO and the sensor has an acceptable response in the range of 1.5-40 kPa.

One of the most important barriers to the detection of the biological autoluminescence (BAL) from biosystems using a non-invasive monitoring approach, in both the in vivo and the in vitro applications, is its very low signal intensity (< 1000 photons/s/cm2). Experimental studies have revealed that the formation of electron excited species, as a result of reactions of biomolecules with reactive oxygen species (ROS), is the principal biochemical source of the BAL which occurs during the cell metabolism. Mitochondria, as the most important organelles involved in oxidative metabolism, are considered to be the main intracellular BAL source. Hence, in order to achieve the BAL enhancement via affecting the mitochondria, we prepared a novel mitochondrial-liposomal nanocarrier with two attractive features including the intra-liposomal gold nanoparticle synthesizing ability and the mitochondria penetration capability. The results indicate that these nanocarriers (with the average size of 131.1 ± 20.1 nm) are not only able to synthesize the gold nanoparticles within them (with the average size of 15 nm) and penetrate into the U2OS cell mitochondria, but they are also able to amplify the BAL signals. Our results open new possibilities for the use of biological autoluminescence as a non-invasive and label-free monitoring method in nanomedicine and biotechnology.