3-D morphological characterization of the liver parenchyma by atomic force microscopy and by scanning electron microscopy

Chain-Like Structures of Biogenic and Nonbiogenic Magnetic Nanoparticles in Vascular Tissues

In this paper, slices of organs from various organisms (animals, plants, fungi) were investigated by using atomic force microscopy and magnetic force microscopy to identify common features of localization of both biogenic and nonbiogenic magnetic nanoparticles. It was revealed that both biogenic and nonbiogenic magnetic nanoparticles are localized in the form of chains of separate nanoparticles or chains of conglomerates of nanoparticles in the walls of the capillaries of animals and the walls of the conducting tissue of plants and fungi. Both biogenic and nonbiogenic magnetic nanoparticles are embedded as a part of the transport system in multicellular organisms. In connection with this, a new idea of the function of biogenic magnetic nanoparticles is discussed, that the chains of biogenic magnetic nanoparticles and chains of conglomerates of biogenic magnetic nanoparticles represent ferrimagnetic organelles of a specific purpose. Besides, magnetic dipole-dipole interaction of biogenic magnetic nanoparticles with magnetically labeled drugs or contrast agents for magnetic resonance imaging should be considered when designing the drug delivery and other medical systems because biogenic magnetic nanoparticles in capillary walls will serve as the trapping centers for the artificial magnetic nanoparticles. The aggregates of both artificial and biogenic magnetic nanoparticles can be formed, contributing to the risk of vascular occlusion. Bioelectromagnetics. 43:119-143, 2022. © 2021 Bioelectromagnetics Society.

Therapeutic effect of bone marrow mesenchymal stem cells in a rat model of carbon tetrachloride induced liver fibrosis

Background

Liver fibrosis is a major medical problem with high mortality and morbidity rates where the formation of regenerative nodules and cirrhosis leads to loss of liver function and may result in the development of hepatocellular carcinoma. bone marrow mesenchymal stem cells (BM-MSCs) have drawn attention as a novel approach for treatment of liver fibrosis. This study aimed to evaluate the therapeutic effect of BM-MSCs on the liver structure in carbon tetrachloride (CCl₄) induced liver fibrosis in male rats relative to resveratrol and Silybum marianum as standard drugs derived from herbal plants.

Methods

Fifty adult male albino rats (Sprague Dawley strain; 180–220 g mean body weight) were purchased from the Laboratory Animal Unit in the Nile Center of Experimental Research, Mansoura, Egypt. Liver function were determined, isolation and preparation of BM- MSCs and detection of cell-surface markers by flow cytometry.

Results

Animals exposed to CCl₄ developed liver injury characterized by significant increase of liver enzymes, malondialdehyde (MDA), tumor necrosis factor alpha (TNFα), and CYP450, inhibition of antioxidant enzymes, and decreased albumin. Treatment with stem cells enhanced liver state more effectively than resveratrol and S. marianum. It significantly decreased AST, ALT, ALP, MDA, TNF-α, and CYP450 and increased albumin, SOD, GSH, GST, and CAT. Histopathological study and atomic force microscope results confirmed the therapeutic effects of MSCs.

Conclusions

BM-MSCs could restore liver structure and function in CCL₄ induced liver fibrosis rat model, ameliorating the toxicity of CCl₄ and improving liver function tests.

Finite element simulation based-on atomic force microscopy and nanoindentation for spruce wood microstructure analysis

Spruce wood (picea abis) has been widely used as structural element, from buildings to musical instruments, due to its outstanding mechanical performances. The main stem transverse section exhibits growth rings formed by periodic fringes patterns, which are constituted by lamellae-tracheid arrangements. In order to improve the understanding of each wood microstructure role, the morphology and crystallinity of earlywood and latewood fibers were examined mainly using scanning electron microscopy, atomic force microscopy, and X-ray difracction. Moreover, measurements of effective elastic modulus and hardness were obtained by nanoindentation tests using a Berkovich indenter in order to confirmed increase in compactness of the wood microstructures. The results indicate that variations in mechanical properties values can be associated with well defined microstructural performances for each characteristic fiber type, where those that belong to latewood fiber showed the most improved behaviors. A finite element simulation of a lamellar-tracheids arrangement was carried out in order to clarify its stiffness and elastic deformation capabilities, as relevant factors contributing to the successful adaptation of picea abis colonies to harsh conditions habitats as well as for its construction applications of string instruments.

Atomic Force Microscopy on Biological Materials Related to Pathological Conditions

Atomic force microscopy (AFM) is an easy-to-use, powerful, high-resolution microscope that allows the user to image any surface and under any aqueous condition. AFM has been used in the investigation of the structural and mechanical properties of a wide range of biological matters including biomolecules, biomaterials, cells, and tissues. It provides the capacity to acquire high-resolution images of biosamples at the nanoscale and allows at readily carrying out mechanical characterization. The capacity of AFM to image and interact with surfaces, under physiologically relevant conditions, is of great importance for realistic and accurate medical and pharmaceutical applications. The aim of this paper is to review recent trends of the use of AFM on biological materials related to health and sickness. First, we present AFM components and its different imaging modes and we continue with combined imaging and coupled AFM systems. Then, we discuss the use of AFM to nanocharacterize collagen, the major fibrous protein of the human body, which has been correlated with many pathological conditions. In the next section, AFM nanolevel surface characterization as a tool to detect possible pathological conditions such as osteoarthritis and cancer is presented. Finally, we demonstrate the use of AFM for studying other pathological conditions, such as Alzheimer's disease and human immunodeficiency virus (HIV), through the investigation of amyloid fibrils and viruses, respectively. Consequently, AFM stands out as the ideal research instrument for exploring the detection of pathological conditions even at very early stages, making it very attractive in the area of bio- and nanomedicine.

Probing the unseen structure and function of liver cells through atomic force microscopy

With the arrival of atomic force microscopy (AFM) about thirty years ago, this new imaging tool opened up a new area for the exploration of biological samples, ranging from the tissue and cellular level down to the supramolecular scale. Commercial instruments of this new imaging technique began to appear in the five years following its discovery in 1986 by Binnig, Quate & Gerber. From that point onwards the AFM has attracted many liver biologists, and the number of publications describing structure-function relationships on the diverse set of liver cells has grown steadily ever since. It is therefore timely to reflect on the achievements of AFM in disclosing the cellular architecture of hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, stellate cells and liver-associated natural killer cells. In this thematic paper, we present new data and provide an in-depth overview of the current AFM literature on liver cell biology. We furthermore include a future outlook on how this scanning probe imaging tool and its latest developments can contribute to clarify various structural and functional aspects of cells in liver health and disease.

Detection and characterization of hepatic engraftment of embryonic stem derived cells by fluorescent stereomicroscopy

BACKGROUND

Embryonic stem (ES) cells have been investigated as a potential replacement therapy for failed organs, such as the liver. However, detection of hepatic engraftment from candidate stem cells has been difficult due to low engraftment efficiency. Previous detection methods required that the graft be processed by molecular and/or immunohistochemical techniques, limiting further functional studies. This study evaluated the use of three-dimensional fluorescent stereomicroscopy for gross detection of ES cell derived hepatic engraftment.

MATERIAL AND METHODS

Murine ES cells expressing the enhanced green fluorescence protein (EGFP) underwent directed endodermal lineage differentiation. Three days after two thirds partial hepatectomy, cells were injected into the liver parenchyma, and livers were harvested at 10 to 20 d and examined by fluorescence stereomicroscopy with a GFP2 long pass filter (100447084; Leica Microsystems AG, Wetzlar, Germany). The sensitivity and reliability of the test was evaluated using quantitative polymerase chain reaction (q-PCR) to assay for the presence of EGFP mRNA in the tissue.

RESULTS

Fluorescent microscopy detected EGFP-positive cells engrafted with normal histology in 5 of 11 specimens. EGFP mRNA was confirmed in all five specimens by q-PCR. Only one of the 11 specimens was negative by fluorescence stereomicroscopy and positive by q-PCR, P < 0.02, Fisher's exact test.

CONCLUSION

Utilization of three-dimensional stereomicroscopy with a GFP2 long pass filter is a powerful and fast screening tool for GFP-ES derived hepatic engraftment.

Growth and Metabolism of Human Hepatocytes on Biomodified Collagen Poly(lactic-co-glycolic acid) Three-Dimensional Scaffold

Hepatic tissue engineering offers a promising approach toward alleviating the need for donor liver, yet many challenges must be overcome including choice of scaffold, cell source, and immunologic barriers. Poly(lactic-co-glycolic acid) (PLGA) polymers are innovative biodegradable materials that have been shown to be useful as scaffolds for seeding and culturing various types of cells. In this study, a porous sponge scaffold of modified PLGA polymer with collagen was investigated for its ability to improve the growth and metabolism of human hepatocytes. We evaluated the biocompatibility of collagen-modified PLGA (C-PLGA) scaffolds with hepatocytes isolated from human liver. Cell adhesion and function (cell density, culture lifespan, albumin synthesis, urea synthesis, and ammonia elimination and diazepam clearance) were assessed during different culture periods. The number of hepatocytes cultured in C-PLGA scaffolds was higher compared with those cultured in PLGA scaffolds without collagen modification, and the lifespan of hepatocytes cultured in C-PLGA scaffolds was longer than that of cells cultured in PLGA scaffolds. Albumin and urea synthesis and ammonia elimination from attached hepatocytes were greater in C-PLGA than in PLGA scaffolds, with the exception of diazepam clearance. Collagen-modified PLGA scaffold is a promising biomaterial for hepatic tissue engineering.