The production efficiency of microbial cell factory is determined by the growth performance, product synthetic capacity, and stress resistance of the strain. Strengthening the stress resistance is the key point to improve the production efficiency of microbial cell factory. Tolerance engineering is based on the response mechanism of microbial cell factory to resist stress. Specifically, it consolidates the cell wall-cell membrane barrier to enhance the defense against stress, accelerates the stress response to improve the damage repair, and creates tolerance evolutionary tools to screen industrial microorganisms with enhanced robustness. We summarize the regulation strategies and forecast the prospects of tolerance engineering, which plays an important role in the microbial cell factories for sustainable production of natural products and bulk chemicals.
Cell Membrane ; Metabolic Engineering

To get an optimal product of orthopaedic implant or regenerative medicine needs to follow trial-and-error analyses to investigate suitable product's material, structure, mechanical properites etc. The whole process from
Cell Differentiation ; Cell Movement ; Cell Proliferation ; Computer Simulation ; Tissue Engineering

Seed cells, biomaterials and growth factors are three important aspects in tissue engineering. Biomaterials mimic extra cellular matrix in vivo, providing a sound environment for cells to grow and attach, so as to maintain cell viability and function. The physicochemical properties and modification molecules of material surface mediate cell behaviors like cell adhesion, proliferation, migration and differentiation, which in turn affect cellular function and tissue regeneration efficacy. Furthermore, the modification molecules of material surface are the direct contact point for cell adhesion and growth. Therefore, the interactions between cells and surface modification molecules are the key to tissue engineering. This review summarizes the effects of surface modification molecules on cell phenotypes and functions.
Biocompatible Materials ; Cell Adhesion ; Cell Differentiation ; Extracellular Matrix ; Tissue Engineering

Magnetic nanoparticles (MNP) have been widely used as biomaterials due to their unique magnetic responsiveness and biocompatibility, which also can promote osteogenic differentiation through their inherent micro-magnetic field. The MNP composite scaffold retains its superparamagnetism, which has good physical, mechanical and biological properties with significant osteogenic effects and . Magnetic field has been proved to promote bone tissue repair by affecting cell metabolic behavior. MNP composite scaffolds under magnetic field can synergically promote bone tissue repair and regeneration, which has great application potential in the field of bone tissue engineering. This article summarizes the performance of magnetic composite scaffold, the research progress on the effect of MNP composite scaffold with magnetic fields on osteogenesis, to provide reference for further research and clinical application.
Cell Differentiation ; Magnetite Nanoparticles ; Osteogenesis ; Tissue Engineering ; Tissue Scaffolds

Ligament tissue engineering is currently a novel approach to the treatment of ligament injury, which can replace the deficiency of autografts. Ligament tissue engineering consists of four basic elements:seed cells, nanoscaffolds, growth factors, and mechanical stimulation. At present, the main problem in ligament tissue engineering is how to control seed cells to ligament cells more controllly. The study found that each physical property of the natural bio ligament and mechanical stimulation (uniaxial stretching) plays an important role in the differentiation of stem cells into ligament cells. Therefore, the design of nanofiber scaffolds must consider the elastic modulus of the material and the material. Structure(material arrangement, porosity and diameter, etc.), elastic modulus and material structure in different ranges will guide cells to differentiate into different lineages. Considering that the ligament is the main force-bearing tissue of the human body, mechanical stimulation is also essential for stem cell differentiation, especially uniaxial stretching, which best meets the stress of the ligament in the body. A large number of studies have found the frequency and amplitude of stretching. And time will also lead the cells to differentiate in different directions. RhoA/ROCK plays a regulatory role in cytoskeletal remodeling and cell differentiation. It is also found that RhoA/ROCK protein participates in the process of nanofiber arrangement and uniaxial stretching to guide stem cells to differentiate into ligament cells, specifically how to influence stem cell differentiation. It is not clear at present that understanding the effects of physical properties on stem cell differentiation and understanding the mechanism of action of RhoA/ROCK protein will provide a new theoretical basis for further optimization of ligament tissue engineering.
Cell Differentiation ; Environment ; Humans ; Ligaments ; Research ; Tissue Engineering ; Tissue Scaffolds

Recently, many researches have been carried out on the production of artificial tissue using tissue engineering. However, studies on fat tissue are still insufficient. The purpose of this study was to examine that alginate sponge can be used as a three-dimensional scaffold for the culture of preadipocytes compared with fibroblasts, and that preadipocytes can differentiate into mature adipocytes in this sponge. The 3T3-L1 preadipocytes and the 3T3 fibroblasts were separately cultured in three-dimensional alginate sponge for 14 days. The morphology of cell and sponge, cell proliferation rate, and glycerol phosphate dehydrogenase activity were evaluated at the indicated periods. The results were as follows; 1. The alginate sponge showed a highly porous, well-interconnected pore structure and the sizes of pores were from 100 to 400micrometer. 2. The fibroblasts in sponge exhibited spindle shape with long irregular fibers on the 7th day and there was no oil-red O stained cell until 14 days. However, the preadipocytes in alginate sponge were round and some of cells transformed into mature fat cells which were stained with oil-red O after 14 days. 3. The proliferation rates of preadipocyte group were increased gradually during the culture period, but lower than those of fibroblast group(P< 0.05). 4. The glycerol phosphate dehydrogenase activities of preadipocyte group were significantly higher than those of fibroblast group during the culture period(P< 0.05), and the activities of 14 day-cultured preadipocytes were about 30 times higher than those of 7 day-cultured preadipocytes. The results suggest that alginate sponge, which has fixed shape and porosity, is adequate three-dimensional scaffolds for culture of fibroblast and preadipocyte. In addition, preadipocytes could be well proliferated and differentiated into adipocyte in the alginate sponge.
Adipocytes ; Cell Proliferation ; Fibroblasts ; Glycerol ; Oxidoreductases ; Porifera* ; Porosity ; Tissue Engineering

Humans ; Myocardium ; Stem Cell Transplantation ; Stem Cells ; Tissue Engineering

Stem cells have been regarded with promising application potential in tissue engineering and regenerative medicine due to their self-renewal and multidirectional differentiation abilities. However, their fate is relied on their local microenvironment, or niche. Recent studied have demonstrated that biophysical factors, defined as physical microenvironment in which stem cells located play a vital role in regulating stem cell committed differentiation. In vitro, synthetic physical microenvironments can be used to precisely control a variety of biophysical properties. On this basis, the effect of biophysical properties such as matrix stiffness, matrix topography and mechanical force on the committed differentiation of stem cells was further investigated. This paper summarizes the approach of mechanical models of artificial physical microenvironment and reviews the effects of different biophysical characteristics on stem cell differentiation, in order to provide reference for future research and development in related fields.
Cues ; Stem Cells ; Cell Differentiation ; Regenerative Medicine ; Tissue Engineering

In this review, we focused on a few obstacles that hinder three-dimensional (3D) bioprinting process in tissue engineering. One of the obstacles is the bioinks used to deliver cells. Hydrogels are the most widely used bioink materials; however, they aremechanically weak in nature and cannot meet the requirements for supporting structures, especially when the tissues, such as cartilage, require extracellular matrix to be mechanically strong. Secondly and more importantly, tissue regeneration is not only about building all the components in a way that mimics the structures of living tissues, but also about how to make the constructs function normally in the long term. One of the key issues is sufficient nutrient and oxygen supply to the engineered living constructs. The other is to coordinate the interplays between cells, bioactive agents and extracellular matrix in a natural way. This article reviews the approaches to improve the mechanical strength of hydrogels and their suitability for 3D bioprinting; moreover, the key issues of multiple cell lines coprinting with multiple growth factors, vascularization within engineered living constructs etc. were also reviewed.
Animals ; Bioprinting ; Cell Line ; Humans ; Hydrogels ; Nanoparticles ; Tissue Engineering

The concept of cell transplantation by tissue engineering has provided numerous possibilities for tissue reconstruction in andrology. Application studies of tissue engineering have been made in such aspects as Leydig cells, testicular prosthesis, penile corporal and penile prosthesis in order to improve, restore or replace the existing tissue function. Although most reconstructive efforts still remain at the experimental stage, several techniques have been applied to clinical practice with satisfactory results. This article briefly reviewed the applications of tissue engineering to andrology.
Andrology ; Animals ; Cattle ; Cell Transplantation ; Humans ; Male ; Rabbits ; Tissue Engineering