Biological Tissues Research Articles

Features of internal absorbed dose microdistribution in biological tissue irradiated by 31SiO2 microparticles compared with dose microdistribution from exposure to 56MnO2 particles.

Radiobiological studies are ongoing to understand the consequences of internal exposure to neutron-activated radioactive microparticles, which were sprayed over experimental rats and mice. Special attention in these experiments is given to internal irradiation with radioactive microparticles with short-lived neutron-activated radionuclides 31Si (T1/2 = 2.62h) and 56Mn (T1/2 = 2.58h), which are among the main dose-forming factors from residual radioactivity activated in soils by neutrons in the first hours after atmospheric nuclear explosions. The presented work is devoted to microdosimetry peculiarities of 31SiO2 and 56MnO2 microparticles. The radiation from 31Si consists of intensive short-range beta particles and gamma rays with very low intensity. It differs from the radiation of 56Mn, which includes intensive beta particles, low energy Auger electrons and very intensive gamma rays. Differences in the energies and intensities of short-range beta particles and penetrating gamma rays emitted by 31SiO2 and 56MnO2 microparticles can lead to differences in the spatial microdistribution of absorbed dose around the corresponding radioactive microparticles embedded in biological tissue. It was found in the presented work that the absorbed doses of beta radiation emitted by 56MnO2 and 31SiO2 microparticles has significant but different spatial gradients with distances in biological tissue that correspond to the typical thickness of epithelial cells of lungs' alveoli and bronchioles. The results obtained are necessary for a better understanding of radiobiological effects of internal exposure by radioactive microparticles with 56Mn and 31Si observed in framework of performed and ongoing radiobiological studies with experimental animals-rats and mice.

Dorsoventral photobiomodulation therapy safely reduces inflammation and sensorimotor deficits in a mouse model of multiple sclerosis

BackgroundNon-invasive photobiomodulation therapy (PBMT), employing specific infrared light wavelengths to stimulate biological tissues, has recently gained attention for its application to treat neurological disorders. Here, we aimed to uncover the cellular targets of PBMT and assess its potential as a therapeutic intervention for multiple sclerosis (MS).MethodsWe applied daily dorsoventral PBMT in an experimental autoimmune encephalomyelitis (EAE) mouse model, which recapitulates key features of MS, and revealed a strong positive impact of PBMT on the sensorimotor deficits. To understand the cellular mechanisms underlying these striking effects, we used state-of-the-art tools and methods ranging from two-photon longitudinal imaging of triple fluorescent reporter mice to histological investigations and patch-clamp electrophysiological recordings.ResultsWe found that PBMT induced anti-inflammatory and neuroprotective effects in the dorsal spinal cord. PBMT prevented peripheral immune cell infiltration, glial reactivity, as well as the EAE-induced hyperexcitability of spinal interneurons, both in dorsal and ventral areas, which likely underlies the behavioral effects of the treatment. Thus, aside from confirming the safety of PBMT in healthy mice, our preclinical investigation suggests that PBMT exerts a systemic and beneficial effect on the physiopathology of EAE, primarily resulting in the modulation of the inflammatory processes.ConclusionPBMT may therefore represent a new valuable therapeutic option to treat MS symptoms.

A Self-Gelling Powder Based on Polyacrylic Acid/Polyethyleneimine/Polyethylene Glycol for High-Performance Hemostasis and Antibacterial Activity

Powder-based hemostatic materials have offered unprecedented opportunities for the effective sealing and repair of irregularly shaped wounds and high-pressure, noncompressible arterial bleeding wounds caused by surgeries, traffic accidents, and wartime injuries. However, inadequate adhesion to bleeding wounds and poor hemostasis in biological tissues remains challenging. Herein, we report a self-gelling hemostatic powder based on polyacrylic acid/polyethyleneimine/polyethylene glycol (named PPG) for rapid hemostasis and effective antibacterial ability. When deposited on bleeding wounds, PPG powder can absorb interfacial liquid and rapidly swell into a physically cross-linked hydrogel in situ within 2 s to form a pressure-resistant physical barrier. Furthermore, the in vivo and in vitro results indicate that, as an effective sealant, the PPG powder possesses ease of use, excellent hemocompatibility, strong antibacterial abilities, and superior blood clotting abilities. The effective hemostatic sealing capability of the PPG powder is demonstrated in a variety of injury models in rats and rabbits. All of these factors show that, with its superior wound treatment abilities, PPG powder is a profound biomaterial for surgical applications.

Mucosa‐Interfacing Capsule for In Situ Sensing the Elasticity of Biological Tissues

AbstractMonitoring the elasticity of soft biological tissues in the gastrointestinal (GI) tract with minimal invasion holds promise for early diagnosis of intestinal fibrosis, colorectal cancer, and other diseases featuring abnormal elasticity. However, existing methods of sensing tissue elasticity have drawbacks such as insufficient resolution for elastography, and discomfort or the requirement of risky anesthesia for flexible endoscopes or implantable devices. Here a wirelessly actuated palpation mechanism is presented, integrated into a swallowable capsule device, offering in situ tissue elasticity measurement with minimal invasiveness. The approach employs a magnetic soft cantilever beam actuated by external magnetic fields to gently press against soft tissues. Mechanical stress and strain are monitored by an onboard magnetic sensor and a strain gauge, allowing for an accurate assessment of tissue elasticity. Additionally, wireless modules utilizing Bluetooth Low Energy (LE) and powered by a battery facilitate real‐time communication. The device operates under external magnetic field control, which can move freely over soft tissues during examinations and palpate suspicious areas. The elasticity sensing mechanism is validated and assessed on both phantom structures and ex vivo porcine colon tissues. The capsule device holds significant promise for assessing tissue physiological conditions and facilitating early disease diagnosis in hard‐to‐reach areas of the body.

Moving Toward Biomimetic Tissue-Engineered Scaffolds

Advancing experimental methodologies to accurately replicate the physiological and pathological characteristics of biological tissues is pivotal in tissue engineering [...]

Development of a sterilization process for amniotic membrane allograft tissue using supercritical carbon dioxide and NovaKill

Amniotic membrane is arguably one of the most popular biological wound dressings on the market today. Various growth factors and cytokines inherent to amniotic membrane tissue have been recognized as key mediators in wound healing and tissue regeneration, giving the tissue its clinical utility. Sterilization methodologies using irradiation are recognized as the gold standard in the field and routinely used to prepare tissue allografts, including amniotic membrane for transplantation. However, irradiation is not always compatible in preserving the physical structure or biochemical factors of biological materials and can potentially result in detrimental effects to the critical quality attributes of allograft tissues. Alternatively, a novel sterilization technique involving supercritical carbon dioxide (SCCO2) has been shown to have minimal effect on the inherent biophysical properties of sensitive biological tissues and tissue-derived products. At BioBridge Global, we have developed a process utilizing SCCO2 technology for the sterilization of an amniotic membrane tissue allograft product. This process, first and foremost, meets industry standards for sterilization while simultaneously maintaining the biochemical composition of the tissue. Our results show that upon SCCO2 sterilization, most of the growth factors tested were conserved, with many at quantities significantly greater than commercially available gamma and electron beam irradiated tissue. The SCCO2-sterilized amniotic membrane allograft is unique in that it is designed to overcome limitations associated with traditional tissue sterilization methodologies, namely, the conservation of key biological factors inherent to native amniotic membrane tissue. It is anticipated that by retaining these biological factors, clinical outcomes associated with the use of SCCO2-sterilized amniotic membrane will be improved.

Advanced 3D-Printed Capstan Clamping System for Accurate Uniaxial Tensile Testing of Biological Soft Tissues

Standardized testing methods for the mechanical characterization of biological soft tissues remain underdeveloped in several domains. Existing clamping methods often induce high stress levels in the clamping region, thereby affecting experimental outcomes. This study introduces a 3D-printed clamping system based on the capstan principle. The capstan system was designed and manufactured using 3D printing technology and optimized to minimize the required gripping pressure while maintaining the natural, non-tapered state of specimens. This optimization helps reduce experimental artifacts and prevents premature tissue failure in the clamping region caused by local stress peaks. Usability trials were conducted using human flexor digitorum profundus (FDP) tendons (n = 15). Results showed that 80% of the tendons failed at the midpoint region, indicating the desired load distribution achieved by the clamping mechanism. The elastic moduli, averaging 316.18 ± 86.73 MPa, and failure load properties, averaging 79.25 ± 19.10 MPa, fell within the range of FDP values reported by other researchers, thereby supporting the validity of the capstan design. Capstan clamping offers a promising add-on for biomechanical testing of soft tissues. Further development is necessary to tailor the clamping design to various tissue geometries and to address issues related to tissue moisture regulation, thereby enhancing the reliability and versatility of the clamping system.

Optical clearing with tartrazine enables deep transscleral imaging with optical coherence tomography.

Imaging deep structures with optical coherence tomography (OCT) is difficult in highly scattering biological tissue, such as the sclera. There is a need to visualize the suprachoroidal space and choroid through the sclera to study suprachoroidal drug delivery. We aim to develop optical methods to image through the highly scattering sclera with a custom-built OCT system to visualize the suprachoroidal space and drug delivery within. We developed a custom handheld OCT scanner to image the anterior segment and suprachoroidal space in ex vivo eye models. Tartrazine (Yellow 5) solution, which has been shown to optically clear biological tissue in the visible regime, was tested as a clearing agent to optimize near infrared OCT imaging through the sclera. Tartrazine dramatically increased OCT signal return from the deeper sclera and choroid and thus enabled visualization of the suprachoroidal drug delivery after transscleral injection. We demonstrated successful optical clearing of the thick, porcine sclera with a compact handheld OCT system to image the suprachoroidal space. We believe there is broader potential to use optical clearing with handheld OCT for a variety of previously inaccessible, highly scattering tissue samples.

Thermal memory and moving linear thermal shocks on heat transfer within biological tissues: an Atangana Baleneau fractional integral

Thermal memory and moving linear thermal shocks on heat transfer within biological tissues: an Atangana Baleneau fractional integral

Photoacoustic Imaging of pH-Sensitive Optical Sensors in Biological Tissues

Photoacoustic imaging is an emerging biomedical imaging technique that enables non-invasive visualization of the optical absorption properties of biological tissues in vivo. Although numerous studies have used contrast agents to achieve high-contrast imaging in deep tissues, targeting specific areas remains a challenge when using agents that are continuously activated. Recent research has focused on developing triggered contrast agents that are selectively activated in target areas. This review delves into the use of pH-triggered contrast agents in photoacoustic imaging, which take advantage of the lower pH of the tumor microenvironment compared to normal tissues. The paper discusses the mechanisms of pH-triggered contrast agents that contribute to improving depth and contrast in photoacoustic tumor imaging. In addition, the integration of functionalities, such as photothermal therapy and drug delivery monitoring, into these agents demonstrates significant potential for biomedical applications.

Adipose tissue biology and effect of weight loss in women with lipedema.

Lipedema is a lipodystrophic disease that is typically characterized by a marked increase in lower-body subcutaneous adipose tissue that is purported to have increased inflammation and fibrosis, impaired microvascular/lymphatic circulation and to be resistant to reduction by weight loss therapy. However, these outcomes have not been adequately studied. We evaluated body composition, insulin sensitivity, metabolic health and adipose tissue biology in women with obesity and lipedema (Obese-LIP) before and after moderate (~9%) diet-induced weight loss. At baseline, people with Obese-LIP had ~23% greater leg fat mass, ~11% lower android-to-gynoid ratio and ~48% greater insulin sensitivity (all P<0.05) than women matched on age, BMI and whole-body adiposity. In Obese-LIP, macrophage content and expression of genes involved in inflammation and fibrosis were greater, whereas lymph/angiogenesis-related genes were lower in thigh than abdominal subcutaneous adipose tissue. Weight loss improved insulin sensitivity and decreased total fat mass, with similar relative reductions in abdominal and leg fat masses, but without changes in markers of inflammation and fibrosis. These results demonstrate that affected adipose tissue in women with lipedema is characterized by increased inflammation and fibrogenesis, and alterations in lymphatic and vascular biology. Moderate diet-induced weight loss improves metabolic function and decreases lower-body adipose tissue mass.

Switchable Adhesion of Hydrogels to Plant and Animal Tissues.

The ability to "switch on" adhesion between a thin hydrogel and a biological tissue can be useful in biomedical applications such as surgery. One way to accomplish this is with an electric field, a phenomenon termed electroadhesion (EA). Here, it is shown that cationic gels can be adhered by EA to tissues across all of biology. This includes tissues from animals, including humans and other mammals; birds; fish; reptiles (e.g., lizards); amphibians (e.g., frogs), and invertebrates (e.g., shrimp, worms). Gels can also be adhered to soft tissues from plants, including fruit (e.g., plums) and vegetables (e.g; carrot). In all cases, EA is induced by a low electric field (DC, 10V) applied for a short time (20 s). After the field is removed, the adhesion persists. The adhesion can also be reversed by applying the field with opposite polarity. In mammals, EA is strong for many tissues (e.g., arteries, muscles, and cornea), but not others (e.g., adipose, brain). Tissues with anisotropic structure show anisotropic adhesion strength by EA. The higher the concentration of anionic polymers in a tissue, the stronger its adhesion to cationic gels. This underscores that EA is mediated by the electrophoresis of chain segments across the gel-tissue interface.

Biomechanical analysis and optimization of sports action training in virtual reality (VR) environment

Over the past years, virtual reality (VR) has become much more popular. VR combines several technologies to provide an immersive digital environment. This environment allows users to engage and react to their actions, creating a virtual world where users feel more present. In biomechanical analysis, researchers analyze the physical characteristics of biological tissues and model the relationship between tissue form and function. Utilizing VR headsets, motion-tracking apparatus, and realistic virtual worlds that simulate actual sports situations are all part of virtual sports training. VR lacks realism, which can be related to the absence of sensory input, making it unsuitable for training fine motor skills. The research aims to perform biomechanical analysis and optimize sports action training inside a VR setting. A mountain gazelle optimizer fine-tuned adjustable convolution neural network (MGO-ACNN) is proposed to examine the joint angle selections utilized by sports action. In this study, human motion image data are utilized to capture various angles of the training action. The data was preprocessed using a Wiener Filter (WF) for the obtained data. Analyzing spatial frequency and orientation in images for feature extraction is accomplished using the Gabor Filter (GF). This approach incorporates VR simulations to provide a more regulated and immersive setting for joint angle analysis during sports training. The proposed method is implemented using Python software. The result demonstrated by the proposed method significantly outperforms the existing algorithms. The performance parameters for accuracy (99.73%), precision (99.75%), recall (99.73%), and F1-score (99.72%) are assessed in this study. The VR experiments indicate that optimal sports preparation involves a sports action while maintaining a batting speed consistent with the joint to lower the center of gravity. This research highlights the more effective, personalized sports training system, leveraging VR to simulate real-world conditions while providing detailed biomechanical insights.

Real-time monitoring of bioelectrical impedance for minimizing tissue carbonization in microwave ablation of porcine liver

The charring tissue generated by the high temperature during microwave ablation can affect the therapeutic effect, such as limiting the volume of the coagulation zone and causing rejection. This paper aimed to prevent tissue carbonization while delivering an appropriate thermal dose for effective ablations by employing a treatment protocol with real-time bioelectrical impedance monitoring. Firstly, the current field response under different microwave ablation statuses is analyzed based on finite element simulation. Next, the change of impedance measured by the electrodes is correlated with the physical state of the ablated tissue, and a microwave ablation carbonization control protocol based on real-time electrical impedance monitoring was established. The finite element simulation results show that the dielectric properties of biological tissues changed dynamically during the ablation process. Finally, the relative change rule of the electrical impedance magnitude of the ex vivo porcine liver throughout the entire MWA process and the reduction of the central zone carbonization were obtained by the MWA experiment. Charring tissue was eliminated without water cooling at 40 W and significantly reduced at 50 W and 60 W. The carbonization during MWA can be reduced according to the changes in tissue electrical impedance to optimize microwave thermal ablation efficacy.

Emerging Non-Breast Implant-Associated Lymphomas: A Systematic Review.

Background: Medical devices used for functional or esthetic purposes improve health and quality of life; however, they are not risk-free. Anaplastic large-cell lymphoma (ALCL), associated with breast implants, is a well-known and recognized distinct lymphoma entity. More recently, additional lymphomas have been reported in relation to prosthesis other than breast implants, as these allow the pericyte to develop into a clone that undergoes a maturation process, progressing toward full malignancy. Methods: We performed a systematic review with a descriptive analysis of data extracted from primary studies following PRISMA guidelines, including the search string "(IMPLANT* OR PROSTHES*) AND LYMPHOM*" in the PubMed, Scopus, Embase, and Google-Scholar databases. Data such as patient sex, age, implant site, prosthesis material, and lymphoma type were analyzed. Statistical methods, including Student's t-test and Fisher's exact test, were employed to compare lymphoma characteristics, with significance set at a p-value < 0.05. Results: From a total of 5992 studies, we obtained 43 case reports and series on a total of 52 patients diagnosed with prosthesis-associated lymphomas. The majority of implant-related lymphoma cases (85%) were of the B-cell type, mostly fibrin-associated large B-cell lymphoma (LBCL). This lymphoma type was more associated with biological (non-human-derived biological tissue), metallic, and synthetic implants (synthesized from non-organic components) (p-value = 0.007). Patients with ALCL had equal frequencies of metal and silicone prostheses (37.5%, 3 cases each), followed by synthetic prostheses (25%, 2 cases). ALCL cases were most common at skeletal (50%) and muscular-cutaneous sites (25%), whereas B-cell lymphomas were predominantly found in cardiovascular implants (50%), followed by skeletal (27%) and muscular-cutaneous (21%) sites. Death attributed to lymphoma took place in 67% of the cases, mostly LBCL occurring in cardiovascular sites. Conclusions: Because the included studies were limited to case reports and series, a potential non-causal link might have been documented between different implant materials, implant sites and lymphoma types. This underscores the importance of further comprehensive research and monitoring of non-breast implants.

Deformation-Dependent Effective Vascular Permeability of a Biological Tissue Containing Parallel Microvessels

Abstract This study describes a micromechanics model for estimating the effective vascular permeability for a biological tissue containing parallel microvessels subjected to finite deformations. The representative volume element in the proposed model consists of a hollow cylinder with the inner radius being the microvessel radius and the outer radius determined using the volume fraction of the microvessels in the tissue. The effective vascular permeability is determined using the Poiseuille equation for the microvascular flow, Darcy's law for the homogenized porous tissue, and finite deformation of the tissue matrix modeled as a nonlinear elastic material. The numerical results show that the effective vascular permeability decreases with an increase in the applied pressure on the tissue. The effective permeability can be significantly larger than the reference permeability when the applied pressure is much smaller than the microvascular pressure. On the other hand, the effective permeability becomes less than 30% of the reference permeability when the applied pressure is greater than two times the microvascular pressure. Finally, the effective vascular permeability increases monotonically with an increasing ratio of the deformed volume to the reference volume of the tissue.

SpatialGE is a User-Friendly Web Application that Facilitates Spatial Transcriptomics Data Analysis.

Spatial transcriptomics (ST) is a powerful tool for understanding tissue biology and disease mechanisms. However, the advanced data analysis and programming skills required can hinder researchers from realizing of the full potential of ST. To address this, we developed spatialGE, a web application that simplifies the analysis of ST data. The application spatialGE provided a user-friendly interface that guides users without programming expertise through various analysis pipelines, including quality control, normalization, domain detection, phenotyping, and multiple spatial analyses. It also enabled comparative analysis among samples and supported various ST technologies. The utility of spatialGE was demonstrated through its application in studying the tumor microenvironment of two data sets: 10X Visium samples from a cohort of melanoma metastasis and Nanostring CosMx fields of vision from a cohort of Merkel cell carcinoma samples. These results support the ability of spatialGE to identify spatial gene expression patterns that provide valuable insights into the tumor microenvironment and highlight its utility in democratizing ST data analysis for the wider scientific community.

Softening, Conformable, and Stretchable Conductors for Implantable Bioelectronics Interfaces

AbstractNeural implantable devices serve as electronic interfaces facilitating communication between the body and external electronic systems. These bioelectronic systems ideally possess stable electrical conductivity, flexibility, and stretchability to accommodate dynamic movements within the body. However, achieving both high electrical conductivity and mechanical compatibility remains a challenge. Effective electrical conductors tend to be rigid and stiff, leading to a substantial mechanical mismatch with bodily tissues. On the other hand, highly stretchable polymers, while mechanically compatible, often suffer from limited compatibility with lithography techniques and reduced electrical stability. Therefore, there exists a pressing need to develop electromechanically stable neural interfaces that enable precise communication with biological tissues. In this study, a polymer that is softening, flexible, conformal, and compatible with lithography to microfabricate perforated thin‐film architectures is utilized. These architectures offer stretchability and improved mechanical compatibility. Three distinct geometries are evaluated both mechanically and electrically under in vitro conditions that simulate physiological environments. Notably, the Peano structure demonstrates minimal changes in resistance, varying less than 1.5× even when subjected to ≈150% strain. Furthermore, devices exhibit a maximum mechanical elongation before fracture, reaching 220%. Finally, the application of multi‐electrode spinal cord leads employing titanium nitride for neural stimulation in rat models is demonstrated.

Method for simultaneous reconstruction of a depth and clear image with a single blurred image in microscopy

The evaluation of imaging blur degradation characteristics of high-magnification optical microscopes is greatly influenced by complex imaging mechanisms, image textures, and illumination, which seriously limit the observation precision at the micro-nano scale. This paper proposes a method for simultaneous reconstruction of the depth and clear image of a blurred image based on the light intensity distribution law of the microscopic imaging system. First, based on the diffraction characteristics of the light in the circular stable cavity, the light intensity distribution function on the imaging plane of the imaging system is established, and the law of the light intensity diffusion degree with the scene depth variation is obtained by curve fitting, that is, the 3D blur degradation model of the system. Secondly, the normalized blurring degree of blurred images with different textures and different illuminations is calculated, and the mapping relationship between the blurring degree of different images and the light intensity diffusion degree of the system is established with the depth change as the intermediate variable. Thirdly, an adaptive spectral clustering method is introduced to classify the blurred images, and the weighted K-nearest neighbor method is used to automatically classify any blurred image and calculate its normalized blurring degree value and the corresponding system energy diffusion value. Based on the 3D blur degradation model and the normalized blurring degree, the depth calculation of the blurred image and the reconstruction of the clear image are realized simultaneously. The precision of the method proposed in this paper is verified by various standard nano-scale grid images and various real biological tissue samples.

Single-pixel imaging through scattering media employing a circular polarization multiplexing metasurface

We propose a scheme of single-pixel imaging through scattering media employing an all-dielectric metasurface, which provides the functions of circular polarization multiplexing and random sampling for single-pixel imaging simultaneously. The former and latter functions are implemented through focusing two orthogonal circular polarization lights with different focal lengths and relative displacements of the metasurface, respectively. Numerical simulations are performed to demonstrate the performance of the metasurface. Whereafter, we simulate the target images projected onto the metasurface and single-pixel imaging reconstructions with these simulated sampling patterns by using the Monte Carlo method, thereby verifying the proposed approach. This technology holds significant potential for applications in microscopic imaging and biological tissue recognition.