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In this paper, we propose an extension of a previous model of cell motility in tissue engineering applications recently developed by the authors. Achieving large-scale production of neo-tissue through biofabrication technologies remains challenging owing to the need of thoroughly optimizing all the relevant process variables, a task hardly attainable through solely trial and error approaches. Therefore, the present work is intended to provide a valid and effective computational-based support for neo-tissue formation, with a specific focus on the preliminary phase of such process, in which cells move through a polymeric scaffold (hydrogel) and then compact into clusters. Cell motility is modeled by resorting to the phase-field method, and by incorporating diffusion of nutrients from the external culture bath as well as the expression by cells of chemoattractant substances that bias the random path they otherwise would follow. The previous model has been enriched by additionally encompassing the secretion of enzymes by cells that cleave the crosslinks between the hydrogel polymer chains. As such, in the present model hydrogel degradation exhibits spatio-temporal variations in its chemo-physical properties related to the local amount of enzymes, which deeply affects cell motility. Numerical results showcase the pivotal importance of the cells micro-environment properties for their crawling in hydrogel scaffolds, opening towards the development of a predictive computational-aided optimization tool for neo-tissue growth in bioprinted scaffolds. [ABSTRACT FROM AUTHOR]

The article highlights the top papers on reproduction research in 2004-2008. According to the author, the top two papers include J. Hanna's paper on the role of decidual NK cells in regulating key developmental processes at the human fetal-maternal inteface and M. Xu's paper on tissue-engineered follicles, which produce live, fertile offspring. Other papers that have seen important advances include the immunology of reproduction and the effect of environmental toxins on reproduction.

Choosing animal-derived regenerative implantable medical devices based on tissue engineering technology as a research theme, this paper presents bibliometric analysis of relative literature from the mainland of China to understand such data as publication year and journal preference, authors' geographic location, research topics and core expertise to predict the research trends and provide an informed basis of decision making for researchers and clinicians. [ABSTRACT FROM AUTHOR]

Today, SF is a natural polymer with unique features, such as excellent mechanical properties, biocompatibility, biodegradability, and low toxicity, which characterize this material with diverse forms for different purposes. Silk nanoparticles, scaffolds, films, and mats are used in various therapeutic and diagnostic strategies including drug/gene delivery, tissue engineering, biomolecule detection, and wound healing. Therefore, a study that examines all SF applications and evaluates its toxicity helps researchers in future projects. In this study, we comprehensively searched all sources of databases in different years about the medical application of various types of SF. Also, we reviewed the toxicity of SF. Several newer papers were selected for reporting and conclusions. In conclusion, the evaluation of the literature revealed that SF is a promising candidate for a wide range of biomedical applications. [ABSTRACT FROM AUTHOR]

The field of tissue engineering involves various methodologies employed to improve or replace biological tissues with extracellular matrices (ECMs). Significant progress has been made, particularly in the fabrication of three-dimensional (3D) scaffolds for replacing damaged tissues or organs. The current review broadly focuses on the various research works carried out involving the use of biomaterials (biopolymers, bio-ceramics and dopants) in this area. A detailed discussion on several scaffold-making modern technologies has also been provided, along with a demonstration of different characterization techniques. Though a number of review papers have been published on biomaterials and fabrication techniques, a very small number focuses on the clinical trials carried out and the commercialization of scaffolds in the biomedical field. Thus, a critical analysis and detailed discussion of some of the clinical trials, market growth, and future demands have been presented in this paper. [ABSTRACT FROM AUTHOR]

Biopolymers are mainly the polymers which are created or obtained from living creatures such as plants and bacteria rather than petroleum, which has traditionally been the source of polymers. Biopolymers are chain-like molecules composed of repeated chemical blocks derived from renewable resources that may decay in the environment. The usage of biomaterials is becoming more popular as a means of reducing the use of non-renewable resources and reducing environmental pollution produced by synthetic materials. Biopolymers' biodegradability and non-toxic nature help to maintain our environment clean and safe. This study discusses how to improve the mechanical and physical characteristics of biopolymers, particularly in the realm of bioengineering. The paper begins with a fundamental introduction and progresses to a detailed examination of synthesis and a unique investigation of several recent focused biopolymers with mechanical, physical, and biological characterization. Biopolymers' unique non-toxicity, biodegradability, biocompatibility, and eco-friendly features are boosting their applications, especially in bioengineering fields, including agriculture, pharmaceuticals, biomedical, ecological, industrial, aqua treatment, and food packaging, among others, at the end of this paper. The purpose of this paper is to provide an overview of the relevance of biopolymers in smart and novel bioengineering applications. The Graphical abstract represents the biological sources and applications of biopolymers. Plants, bacteria, animals, agriculture wastes, and fossils are all biological sources for biopolymers, which are chemically manufactured from biological monomer units, including sugars, amino acids, natural fats and oils, and nucleotides. Biopolymer modification (chemical or physical) is recognized as a crucial technique for modifying physical and chemical characteristics, resulting in novel materials with improved capabilities and allowing them to be explored to their full potential in many fields of application such as tissue engineering, drug delivery, agriculture, biomedical, food industries, and industrial applications. [ABSTRACT FROM AUTHOR]

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Tissue engineering is a relatively recent research area aimed at developing artificial tissues that can restore, maintain, or even improve the anatomical and/or functional integrity of injured tissues. Otolaryngology, as a leading surgical specialty in head and neck surgery, is a candidate for the use of these advanced therapies and medicinal products developed. Nevertheless, a knowledge-based analysis of both areas together is still needed. The dataset was retrieved from the Web of Science database from 1900 to 2020. SciMAT software was used to perform the science mapping analysis and the data for the biomedical translation identification was obtained from the iCite platform. Regarding the analysis of the cognitive structure, we find consolidated research lines, such as the generation of cartilage for use as a graft in reconstructive surgery, reconstruction of microtia, or the closure of perforations of the tympanic membrane. This last research area occupies the most relevant clinical translation with the rest of the areas presenting a lower translational level. In conclusion, Tissue engineering is still in an early translational stage in otolaryngology, otology being the field where most advances have been achieved. Therefore, although otolaryngologists should play an active role in translational research in tissue engineering, greater multidisciplinary efforts are required to promote and encourage the translation of potential clinical applications of tissue engineering for routine clinical use. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is a pure biopolymer with abundant sources. BC has been used in wound dressings, artificial blood vessels, bone tissue engineering, and other applications because of its microporosity, superior water retention, thermal stability, and biocompatibility. The tensile strength of pure BC in wet state is weak, and the water holding capacity is above 90%, which limits its application. However, the mechanical properties of dehydrated BC are excellent at the expense of toughness, which is not enough to meet the demand of high additional-value materials, such as high strength flexible electronic device substrate, wearable electronic devices, vibration film for microphone and earphone, and others. Therefore, it is of great importance to systematically investigate the strategies to improve the mechanical properties of BC. Herein, this paper demonstrates the intrinsic factors affecting the mechanical properties of BC, along with the strategies to enhance the mechanical properties. Compared with the well-known adhesion reinforcement and chemical modification, six strategies to enhance the mechanical properties were discussed thoroughly in this paper. In addition, layer-by-layer self-assembly and orderly arrangement of fibrils are proposed in this paper to improve the mechanical properties of BC, which have not been described in detail in previous literature. [ABSTRACT FROM AUTHOR]

With the efficient cross-linking abilities and the flexible regulation abilities to the performances of cross-linked products, the multi-functional aliphatic epoxides were once widely used to cross-link the collagen-based materials in the last century. In present work, the multi-functional epoxides were used to construct and cross-link collagen sponges for tissue engineering scaffolds, which was hoped to board the theoretical system of epoxides and explore their potentials for modern applications. The bi- to tetra-functional epoxides were used to cross-link collagen solutions and establish the gel-like precursors, then using freeze-drying to form the final sponges. The SEM observed that the sponges had shown regular porous structures with a wide range of pore sizes from 160 to 440 μm. The sponges had presented the resistance to enzymatic degradation, shape-remaining ability, and reversible compressibility in aqueous environments, which all could be regulated through the functionalities of epoxides. The regulation abilities of multi-functional epoxides on the performances of sponges had been mainly achieved through the cross-linking degrees that the higher functionality of epoxides would bring higher cross-linking degree. Such higher cross-linking degrees could enhance the elastic behaviors of gel-like precursors, and improve the compressive strengths and thermal stabilities of sponges. Nevertheless, the multi-functional epoxides had barely affected the safety of collagen sponges at the cellular level according to the results of CCK8 assay and the SEM and CLSM images of L929 fibroblasts cultured on the cross-sections of sponges. [ABSTRACT FROM AUTHOR]

Porous materials are pivotal in emerging fields like tissue engineering, scaffold, and drug delivery due to their distinctive porosity-driven functional properties. This paper describes how to achieve multiscale porosity in food-based composites through a thermally activated gelatinization process of amylopectin molecules coupled with 3D printing. By controlling printing paths, macropores are engineered, while degree of gelatinization governs micro- and nanopores formation. Process-microstructure relationship reveals that longer preheating treatments at higher gelatinization temperatures significantly reduce micro-pore area by over twofold and nanopore surface area by over threefold. These results provide a promising route to fabricate food-based composite with tailorable microstructures. [ABSTRACT FROM AUTHOR]

Background: Large and complex defects requiring reconstruction are challenging for orthopaedic surgeons. The use of human acellular dermal (HAD) matrices to augment large soft tissue defects such as those seen in massive rotator cuff tears, knee extensor mechanism failures and neglected Tendo-Achilles tears has proven to be a valuable tool in surgeons reconstructive armamentarium. Different methods for allograft decellularization and preservation alter the native properties of the scaffold. Traditional processing and preservation methods have shown to have drawbacks that preclude its widespread use. Some of the common issues include inferior biomechanical properties, the risk of rejection, limited customization, difficulty in storing and transporting, the requirement of pre-operative preparation, and last but not the least increased cost. Methods: We describe a novel processing and preservation method utilizing a two-step non-denaturing decellularization method coupled with preservation using a water-sequestering agent (glycerol) to remove immunogenic components while retaining biomechanical properties. The efficiency of this novel process was compared with the traditional freeze-drying method and verified by histological evaluation and biomechanical strength analysis. Results: The absence of cellular components and matrix integrity in hematoxylin and eosin-stained glycerol-preserved HAD (gly-HAD) samples compared to freeze-dried HAD (FD-HAD) demonstrated effective yet gentle decellularization. Biomechanical strength analysis revealed that gly-HADs are stronger with an ultimate tensile load to the failure strength of 210 N compared to FD-HAD (124N). The gly-HADs were found to have an optimal suture–retention strength of 126 N. Finally, sterility testing of the resultant grafts was checked to ensure a sterility assurance level of 10−6 to establish implantability. Conclusion: The novel processing and preservation technique is described in this paper to create a Human Acellular Dermis with higher biomechanical strength and superior histological characteristics. The processing and preservation technique ensured high sterility assurance levels to establish implantability. [ABSTRACT FROM AUTHOR]

Objective: Cultured meat is considered to be a viable alternative to conventional flesh to satisfy the increasing human demand for meat. However, current cultured meat products fail to meet consumer expectations. This paper aims to summarize existing methods of cultured meat production, especially 3D bioprinting of cultured meat, which is an emerging approach with unique advantages. By discussing the advantages and shortcomings of the existing techniques, the prospect for the future development of cultured meat is provided. Methods: The potential ecological sustainability of cultured meat is evaluated in order to determine the necessity for its development. The advancements and limitations of cultured meat based on tissue engineering, 3D printing of meat, and 3D bioprinting of cultured meat are discussed. Future trends in 3D bioprinting of cultured meat are predicted, as well as potential challenges in this field. Results: (1) Cultured meat is an ecologically sustainable alternative to conventional meat. (2) Cultured meat based on tissue engineering has allowed the creation of cultured muscle, adipose, and multi-component meat. The issues are that the shape of the products is unpredictable, and the process of producing large-size and multi-component cultured meat is arduous, which is not conducive to sustainable manufacturing. (3) 3D printing has been utilized in the customized processing of meat to achieve personalized demands. However, it relies on natural meat for its raw materials and cannot replace livestock production. (4) There have been preliminary attempts to use 3D bioprinting technology for cultured meat production. It combines the advantages of tissue engineering and 3D printing, which is able to create cultured beef, pork, and seafood. (5) The potential advantages of 3D bioprinting of cultured meat are higher quality and yield, enhanced cost-effectiveness, and superior ecological sustainability. (6) In the future, 3D bioprinting of cultured meat will move towards multi-component products, integrated fabrication, and cloud manufacturing. (7) The urgent issues in 3D bioprinting of cultured meat are the development of edible and printable biomaterials, the advancement of bioprinting techniques, and the life cycle assessment of manufacturing process. Conclusion: 3D bioprinting is a promising avenue to improve the quality and yield, reduce production costs, and enhance the ecological sustainability of cultured meat. It may allow people to satisfy the growing demand for meat in a sustainable manner. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing (or additive manufacturing) is a manufacturing technology that produces 3D objects layer-by-layer automatically. Since the 1980s, 3D printing has been used in various fields, ranging from automobiles to medicine. In regenerative medicine and tissue engineering fields, this technique has developed with the advance of the ink material mostly composed of the live cells within. Additionally, it is also required to meet the mechanical durabilities, easy printability, and low toxic effects or immunogenicity. Therefore, it is essential to consider the suitability of ink materials in 3D bio-printing. Various printing materials can be selected, whether single or hybrid, by incorporating two or more inks. Among them, this paper focuses mainly on two major categories: natural polymers and synthetic polymers. The natural polymers have similar properties with extracellular matrix, biocompatibility, and biodegradability. On the other hand, synthetic polymers have adjustable mechanical properties and crosslinking ability according to various stimuli. This paper describes the properties, advantages/disadvantages, and applications of bioink material candidates. [ABSTRACT FROM AUTHOR]

Highlights the All-Russia National Conference "Cell Tissue Engineering of Plants and Animals," in Moscow, Russia, on December 15-16, 2002. Attention attracted by papers dealing with the biology of neural stem cells; Emphasis on embryonic stem cells; Other papers presented.

Due to the increasing prevalence of bone disorders among people especially in average age, the future of treatments for osseous abnormalities has been illuminated by scaffold-based bone tissue engineering. In this study, in vitro and in vivo properties of 58S bioactive glass-based scaffolds for bone tissue engineering (bare (B.SC), Zein-coated (C.SC), and Zein-coated containing Kaempferol (KC.SC)) were evaluated. This is a follow-up study on our previously published paper, where we synthesized 58S bioactive glass-based scaffolds coated with Kaempferol-loaded Zein biopolymer, and characterized from mostly engineering points of view to find the optimum composition. For this aim, in vitro assessments were done to evaluate the osteogenic capacity and biological features of the scaffolds. In the in vivo section, all types of scaffolds with/without bone marrow-derived stem cells (BMSC) were implanted into rat calvaria bone defects, and potential of bone healing was assessed using imaging, staining, and histomorphometric analyses. It was shown that, Zein-coating covered surface cracks leading to better mechanical properties without negative effect on bioactivity and cell attachment. Also, BMSC differentiation proved that the presence of Kaempferol caused higher calcium deposition, increased alkaline phosphatase activity, bone-specific gene upregulation in vitro. Further, in vivo study confirmed positive effect of BMSC-loaded KC.SC on significant new bone formation resulting in complete bone regeneration. Combining physical properties of coated scaffolds with the osteogenic effect of Kaempferol and BMSCs could represent a new strategy for bone regeneration and provide a more effective approach to repairing critical-sized bone defects. [ABSTRACT FROM AUTHOR]

This review paper is primarily focused on bioprinting technology for biomedical applications. Bioprinting can be utilized for fabrication of wide range of tissue, based on which this chapter describes in detail its application in tissue regeneration. Further, the difficulties and potential in developing a construct for tissue regeneration are discussed herein. In this review paper, application of 3D bioprinting in tissue regeneration will be discussed in depth. [ABSTRACT FROM AUTHOR]

Pelvic floor disorders (PFDs) include a series of conditions that can be poorly tolerated, negatively affecting the quality of life. Current treatment options show unsatisfactory results and new ones are therefore needed. Stem cell (SC) therapy might be an alternative treatment strategy. This systematic review aims to define the state of art of SC therapy for PFDs in clinical trials, by systematically reviewing the available evidence. A systematic search strategy was conducted up to November 7, 2020, in PubMed, Scopus, Cochrane Library, and ISI Web of Science. Preclinical studies on animal models were not considered. Studies were included when the patients were affected by any PFDs and cells were isolated, cultured, and characterized as SC. The study protocol was registered in PROSPERO (CRD42020216551). A total of 11 prospective clinical studies were included in the final assessment, specifically 7 single-arm studies dealing with SC therapy for stress urinary incontinence and 4 with anal incontinence. Among the latter, there were two prospective, single-arm studies and two randomized controlled trials. No papers concerning the use of SC for prolapse repair were retrieved. Due to the great heterogeneity, data pooling was not possible. Stem cell injection resulted in a safe procedure, with few mild adverse side effects, mostly related to harvesting sites. However, a clear beneficial impact of SC treatment for the treatment of pelvic floor disorders could not be demonstrated. Further larger targeted studies with control arms are needed before any conclusions can be made. [ABSTRACT FROM AUTHOR]

Biomedical engineering breakthroughs and increased patient expectations and requests for more comprehensive care are propelling the field of regenerative dentistry forward at a fast pace. Stem cells (SCs), bioactive compounds, and scaffolds are the mainstays of tissue engineering, the backbone of regenerative dentistry. Repairing damaged teeth and gums is a significant scientific problem at present. Novel therapeutic approaches for tooth and periodontal healing have been inspired by tissue engineering based on mesenchymal stem cells (MSCs). Furthermore, as a component of the MSC secretome, extracellular vesicles (EVs) have been shown to contribute to periodontal tissue repair and regeneration. The scaffold, made of an artificial extracellular matrix (ECM), acts as a supporting structure for new cell development and tissue formation. To effectively promote cell development, a scaffold must be non-toxic, biodegradable, biologically compatible, low in immunogenicity, and safe. Due to its promising biological characteristics for cell regeneration, dental tissue engineering has recently received much attention for its use of natural or synthetic polymer scaffolds with excellent mechanical properties, such as small pore size and a high surface-to-volume ratio, as a matrix. Moreover, as a bioactive material for carrying MSC-EVs, the combined application of scaffolds and MSC-EVs has a better regenerative effect on dental diseases. In this paper, we discuss how MSCs and MSC-derived EV treatment may be used to regenerate damaged teeth, and we highlight the role of various scaffolds in this process. The potential of utilizing mesenchymal stem cells (MSCs) and their derivatives (MSC-EVs) inserted into the scaffold to regenerate dental diseases is illustrated in this figure. Synthetic and natural scaffolds transport these cells to facilitate their safe and targeted delivery to the intended tissue. [ABSTRACT FROM AUTHOR]

The aim of the experiment was to study the morphology of collagen-based scaffolds modified by caffeic acid, ferulic acid, and gallic acid, their swelling, and degradation rate, as well as the biological properties of scaffolds, such as antioxidant activity, hemo- and cytocompatibility, histological observation, and antibacterial properties. Scaffolds based on collagen with phenolic acid showed higher swelling rate and enzymatic stability compared to scaffolds based on pure collagen, and the radical scavenging activity was in the range 85–91%. All scaffolds were non-hemolytic and compatible with surrounding tissues. Collagen modified by ferulic acid showed potentially negative effects on hFOB cells as a significantly increased LDH release was found, but all of the studied materials had antimicrobial activity against Staphylococcus aureus and Escherichia coli. It may be assumed that phenolic acids, such as caffeic, ferulic, and gallic acid, are modifiers and provide novel biological properties of collagen-based scaffolds. This paper provides the summarization and comparison of the biological properties of scaffolds based on collagen modified with three different phenolic acids. [ABSTRACT FROM AUTHOR]

Background: Tissue engineering, as stated by Langer and Vacanti, is an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve biological tissue function or a whole organ. Tissue engineering incorporates several important components in order to create in vivo mimicry. Those factors are tissue specific and each organ poses a unique scope of requirements. Several unique fabrication methods exist: extrusion printing, inkjet, laser-assisted printing, stereolithography, and FRESH. Methods: A systematic literature review via PubMed was performed to identify appropriate publications incorporating "keyword" phrases, "soft tissue", "3D-printing", "tissue engineering", and "bio-engineering", between Jan 2015 and Jan 2022 according to the PRISMA standard flowchart. Results: Search result yielded 1350 papers. Two-hundred seventy eigth papers were assessed for inclusion criteria. Fifty-five full text articles were included in the qualitative synthesis. Articles were analyzed by the senior author (Y.W.) and divided to various fields of research: 3D-bioprinting technology, cellular component, bioink matrix and clinical implications. Each of these fields has undergone substantial development in recent years. Conclusions: Due to the importance of 3D bioprinting and the never-ending progress in this field and its contribution to the field of medicine in term of clinical implementations, we believe that surgeons and physicians alike should familiarize themselves with the basic concepts of 3D-bio printing in order to keep track of the ever-growing literature of this fascinating sphere. We believe that a stepwise exposure of young physicians to this field is mandatory, from their basic science training through their internship and continuing advanced education. Level of evidence: Not gradable. [ABSTRACT FROM AUTHOR]

In recent years, biodegradable porous Zn-based scaffolds employed as bone tissue engineering scaffolds to treat large bone defects have attracted attention of many researchers. Although porous Zn-based scaffolds have acceptable biocompatibility in vivo and more reasonable degradation rates than degradable Mg-based and Fe-based scaffolds, there is still a certain distance between the porous Zn-based scaffolds that have been developed and the ideal bone tissue engineering scaffolds. In this paper, the methods that had been used to prepare porous Zn-based scaffolds were summarized, and the advantages and disadvantages of each method were analysed. The mechanical properties of porous Zn-based scaffolds were reviewed, and the compressive, tensile, and fatigue behaviors of the scaffolds were also discussed. The degradation properties of porous Zn-based scaffolds in vitro were summarized, and the degradation rules were found. Comparing the degradation properties of bulk Zn-based materials and porous Zn-based scaffolds, the degradations of porous Zn-based scaffolds were more deeply understood. In addition, the degradation behaviors of porous Zn-based scaffolds in vivo were also reviewed. The antibacterial properties of porous Zn-based scaffolds were summarized. Reviewing the experimental results of the biocompatibility of porous Zn-based scaffolds in vitro and in vivo, the main factor affecting the biocompatibility was identified, and the reasons for the large gap between the biocompatibility results in vivo and in vitro were discussed. At last, the problems faced by the current porous Zn-based scaffolds used as bone tissue engineering scaffolds were proposed, and the potential solutions to these problems were also suggested. [ABSTRACT FROM AUTHOR]

The role of the mechanical environment in defining tissue function, development and growth has been shown to be fundamental. Assessment of the changes in stiffness of tissue matrices at multiple scales has relied mostly on invasive and often specialist equipment such as AFM or mechanical testing devices poorly suited to the cell culture workflow.In this paper, we have developed a unbiased passive optical coherence elastography method, exploiting ambient vibrations in the sample that enables real-time noninvasive quantitative profiling of cells and tissues. We demonstrate a robust method that decouples optical scattering and mechanical properties by actively compensating for scattering associated noise bias and reducing variance. The efficiency for the method to retrieve ground truth is validated in silico and in vitro, and exemplified for key applications such as time course mechanical profiling of bone and cartilage spheroids, tissue engineering cancer models, tissue repair models and single cell. Our method is readily implementable with any commercial optical coherence tomography system without any hardware modifications, and thus offers a breakthrough in on-line tissue mechanical assessment of spatial mechanical properties for organoids, soft tissues and tissue engineering. A method is described for assessing spatial mechanical properties for organoids, soft tissues and tissue engineering. [ABSTRACT FROM AUTHOR]

Scaffolds engineered for in vitro tissue engineering consist of multiple pores where cells can migrate along with nutrient-rich culture medium. The presence of the nutrient medium throughout the scaffold pores promotes cell proliferation, and this process depends on several factors such as scaffold geometry, nutrient medium flow rate, shear stress, cell-scaffold focal adhesions and elastic properties of the scaffold material. While numerous studies have addressed the first four factors, the mathematical approach described herein focuses on cell proliferation rate in elastic scaffolds, under constant flux of nutrients. As cells proliferate, the scaffold pores radius shrinks and thus, in order to sustain the nutrient flux, the inlet applied pressure on the upstream side of the scaffold pore must be increased. This results in expansion of the elastic scaffold pore, which in turn further increases the rate of cell proliferation. Considering the elasticity of the scaffold, the pore deformation allows further cellular growth beyond that of inelastic conditions. In this paper, our objectives are as follows: (i) Develop a mathematical model for describing fluid dynamics, scaffold elasticity and cell proliferation for scaffolds consist of identical nearly cylindrical pores; (ii) Solve the models and then simulate cellular proliferation within an elastic pore. The simulation can emulate real life tissue growth in a scaffold and offer a solution which reduces the numerical burdens. Lastly, our results demonstrated are in qualitative agreement with experimental observations reported in the literature. [ABSTRACT FROM AUTHOR]

Objectives: This report explores the possibility of synthesizing enzyme-metal-organic framework (MOF) composites by ink-jet printing. Results: This study demonstrates that the direct synthesis of patterned enzyme-metal-organic framework (MOF) composites on various substrates including paper and polymeric films can be readily achieved by ink-jet printing bio-inks containing protein molecules, metal ions, and organic ligands loaded, respectively, in different cartridges. The formed Cytochrome c (Cyt c)-MOF composites on filter paper by ink-jet printing can be used for rapid detection of hydrogen peroxide in solution. Conclusions: This technique opens possibilities of scalable, controllable, and designable fabrication of functional protein-MOF hybrid surface with promising applications in future bio-related application fields such as biosensing, wearable bioelectronics, artificial biomimetic membranes, and tissue engineering. [ABSTRACT FROM AUTHOR]

Nanomembrane is an independent structure with a thickness of 1–100 nm and with much large lateral dimensions. Due to the unique properties of nanomembranes, research on the category of structures is valuable. Furthermore, nanomembranes have received a lot of attention from scientists because those types of structures can be used in various bioengineering branches. However, biocompatibility and toxicity of nanomembranes are not fully understood yet. In terms of mechanical engineering, nanomembranes must have mechanical strength, surface treatment to ensure the required structure. Mechanical properties can be affected through the material, fabrication method, porosity. For the application of nanomembranes in bioengineering, it is important to develop research to improve the biocompatibility and mechanical strength of nanomembranes. In this paper, according to the recent achievements, classification of materials, fabrication methods, and porosity are reviewed and summarized. Applications of nanomaterials in tissue engineering (bone and skin) as well as in drug delivery systems are also presented. The aim of the paper is to highlight the role of synthetic nanomembranes in the context of nanotechnologies and provide applications of functionalized nanomembranes in bioengineering. Before continuing noble and costly research, it is necessary to know the key principles and references for understanding progress of nanomembranes over the past decade. [ABSTRACT FROM AUTHOR]

Since the second half of the 20th century, bioceramics are widely used as a substitute for hard tissue engineering. Bioceramics including zirconia, alumina, hydroxyapatite, and bioactive glass plays a vital role in the design of tissue engineering scaffolds with tailor-made properties. The bioceramics scaffold has been used to replace or regenerate the tissue of the human body due to its excellent mechanical strength, biocompatibility, chemical stability, corrosion restriction behavior, and wear resistance. The advancement in technology has made the form of bioceramics and their function, structure, and composition more diversified, and manifold. Considering the promising role of the use of bioceramics in tissue engineering, we proposed this review, presenting the classification of bioceramics, their physiochemical properties, degradation pathway, product development so far, and their application in tissue engineering. The calcium phosphate and bioglass-based composite scaffold have also been discussed in detail. Furthermore, this paper also discussed the toxicity evaluation and market perspective of bioceramics. Thus, this review gives a complete insight into bioceramics for tissue engineering applications. [ABSTRACT FROM AUTHOR]

The mask-image-projection-based stereolithography (MIP-SL) is one of the most promising methods for preparing biological scaffolds. In this paper, a mask image planning method based on grayscale regulation is proposed based on the characteristics of the bio-scaffold structure. It is based on support vector machine method and iterative method to intelligently regulate mask pixel gray value, which can achieve low exposure error and accordingly better curing quality. Furthermore, in order to discuss the properties of grayscale regulation, single pixel light intensity function acquisition experiment and stereolithography simulation based on light intensity function and mask grayscale regulation experiment were carried out. Results show that the light intensity distribution function of single pixel follows Gaussian distribution, and the light intensity energy between adjacent pixels will affect each other. The grayscale regulation scheme can improve the degree of reduction of the cured shape of the resin and is beneficial to the curing accuracy. [ABSTRACT FROM AUTHOR]

3D bioprinting of biomimetic tissue is critical for engineering artificial soft tissues and organs. However, the lack of simultaneously printed multiscale blood vessels within the scaffolds and the cell damage in the bioprinting nozzle decreased viability and limited the potential of printed tissues. This paper adopted 3D-printed sacrificial molds for the fabrication of hydrogel scaffolds with internal channels. The process fills slow-gelling sodium alginate into 3D-printed water-soluble PVA molds to create channels within the hydrogel. The results showed that hydrogel and crosslinker concentration have significant effects on gelation time, channel width, and scaffold compressive strength. Simulation results showed that both higher hydrogel and crosslinker concentrations contribute to higher residual stress within the scaffolds. This novel scaffold fabrication process has the potential for the vascularization of various organ and tissue models for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Presently on a global scale, one of the major concerns is to find effective strategies to manage the agricultural waste to protect the environment. One strategy that has been drawing attention among the researchers is the development of biocompatible materials from agricultural waste. This strategy implies successful conversion of agricultural waste products (e.g.: cellulose, eggshell etc.) into building blocks for biomaterial development. Some of these wastes contain even bioactive compounds having biomedical applications. The replacement and augmentation of human tissue with biomaterials as alternative to traditional method not only bypasses immune-rejection, donor scarcity, and maintenance; but also provides long term solution to damaged or malfunctioning organs. Biomaterials development as one of the key challenges in tissue engineering approach, resourced from natural origin imparts better biocompatibility due to closely mimicking composition with cellular microenvironment. The "Garbage In, Biomaterials Out (GIBO)" concept, not only recycles the agricultural wastes, but also adds to biomaterial raw products for further product development in tissue regeneration. This paper reviews the conversion of garbage agricultural by-products to the biocompatible materials for various biomedical applications. The agro-waste biomass processed, purified, modified, and further utilized for the fabrication of biomaterials-based support system for tissue engineering applications to grow living body parts in vitro or in vivo. [ABSTRACT FROM AUTHOR]

The influence of surface topography on stem cell behavior and differentiation has garnered significant attention in regenerative medicine and tissue engineering. The cell-imprinting method has been introduced as a promising approach to mimic the geometry and topography of cells. The cell-imprinted substrates are designed to replicate the topographies and dimensions of target cells, enabling tailored interactions that promote the differentiation of stem cells towards desired specialized cell types. In fact, by replicating the size and shape of cells, biomimetic substrates provide physical cues that profoundly impact stem cell differentiation. These cues play a pivotal role in directing cell morphology, cytoskeletal organization, and gene expression, ultimately influencing lineage commitment. The biomimetic substrates’ ability to emulate the native cellular microenvironment supports the creation of platforms capable of steering stem cell fate with high precision. This review discusses the role of mechanical factors that impact stem cell fate. It also provides an overview of the design and fabrication principles of cell-imprinted substrates. Furthermore, the paper delves into the use of cell-imprinted polydimethylsiloxane (PDMS) substrates to direct adipose-derived stem cells (ADSCs) differentiation into a variety of specialized cells for tissue engineering and regenerative medicine applications. Additionally, the review discusses the limitations of cell-imprinted PDMS substrates and highlights the efforts made to overcome these limitations.Graphical Abstract: The influence of surface topography on stem cell behavior and differentiation has garnered significant attention in regenerative medicine and tissue engineering. The cell-imprinting method has been introduced as a promising approach to mimic the geometry and topography of cells. The cell-imprinted substrates are designed to replicate the topographies and dimensions of target cells, enabling tailored interactions that promote the differentiation of stem cells towards desired specialized cell types. In fact, by replicating the size and shape of cells, biomimetic substrates provide physical cues that profoundly impact stem cell differentiation. These cues play a pivotal role in directing cell morphology, cytoskeletal organization, and gene expression, ultimately influencing lineage commitment. The biomimetic substrates’ ability to emulate the native cellular microenvironment supports the creation of platforms capable of steering stem cell fate with high precision. This review discusses the role of mechanical factors that impact stem cell fate. It also provides an overview of the design and fabrication principles of cell-imprinted substrates. Furthermore, the paper delves into the use of cell-imprinted polydimethylsiloxane (PDMS) substrates to direct adipose-derived stem cells (ADSCs) differentiation into a variety of specialized cells for tissue engineering and regenerative medicine applications. Additionally, the review discusses the limitations of cell-imprinted PDMS substrates and highlights the efforts made to overcome these limitations. [ABSTRACT FROM AUTHOR]

In tissue engineering, scaffolds must be designed or tailored with the structures and mechanical behavior appropriate for repairing the defective tissue, which, however, remains unachievable. In this paper, we present a modular scaffold design method and illustrate its effectiveness by using three basic units with different structures and porosities and then rigorously stacking them into six scaffold designs of varying porosities or gradients and thus mechanical behaviors. Samples of designed scaffolds were prepared by the selective laser melting (SLM) technique using Al-Si10-Mg powder and the mechanical properties were examined by compressive testing. In parallel, the mechanical behavior of scaffolds was simulated based on the Johnson–Cook model. Furthermore, a performance optimization strategy was developed based on genetic algorithm, which allows one to design scaffolds from basic units with tailored mechanical properties and porosity. Our results show that among the examined six scaffolds, the triangular modular design has strong load-bearing capacity and energy absorption capacity, and the hexagonal modular design has a good deformation capacity with high energy absorption efficiency. The deformation behavior of the modular design with a radial gradient of porosity and the one with a local-varying porosity show that shear fracture occurs at 45° to the loading direction. Also, the elastic modulus and porosity of the scaffolds designed using the developed optimization strategy are close. to the targeted values. Taken together, the present study illustrates the modular design method allows one to design scaffolds with tailored structures and mechanical properties, representing a big advance for developing scaffolds in tissue engineering. [ABSTRACT FROM AUTHOR]

This paper describes the use of impulse control of an acoustic field to create complex and precise particle patterns and then dynamically manipulate them. We first demonstrate that the motion of a particle in an acoustic field depends on the applied impulse and three distinct regimes can be identified. The high impulse regime is the well established mode where particles travel to the force minima of an applied continuous acoustic field. In contrast acoustic field switching in the low impulse regime results in a force field experienced by the particle equal to the time weighted average of the constituent force fields. We demonstrate via simulation and experiment that operating in the low impulse regime facilitates an intuitive and modular route to forming complex patterns of particles. The intermediate impulse regime is shown to enable more localised manipulation of particles. In addition to patterning, we demonstrate a set of impulse control tools to clear away undesired particles to further increase the contrast of the pattern against background. We combine these tools to create high contrast patterns as well as moving and re-configuring them. These techniques have applications in areas such as tissue engineering where they will enable complex, high fidelity cell patterns. [ABSTRACT FROM AUTHOR]

Polycaprolactone (PCL)-based scaffolds have great potential in various tissue engineering applications because of their biodegradability, high mechanical strength, and easy fabrication using different 3D printing methods. However, previous research has only focused on developing and examining each PCL-based scaffold printing method's merits and limitations separately. Thus, the lack of a systematic comparison of the various methods to recommend the most appropriate one for each application remains. This paper provides an overview of different PCL-based scaffold printing methods. Four typical 3D printing methods for fabricating PCL-based scaffolds and five important evaluation criteria including quality, usage, productivity, cost, and flexibility are identified. The integrated fuzzy-analytical hierarchy process (i-FAHP) and sensitivity analysis are proposed as multi-criteria decision-making methods for selecting the most appropriate scaffold printing method (SPM) under constrained construction and material types. Customized software based on a flexible fuzzy-AHP expert system is built to support decision-makers in determining the optimal SPM quickly and effectively. The result shows that the melt-based extrusion method is optimal for different scaffold types. This study's findings will be useful for developing biomaterial and multi-head 3D bioprinters for customized and commercial tissue engineering applications. [ABSTRACT FROM AUTHOR]

Background: Tremendous progress has been made in the field of cartilage repair and regeneration, particularly with tissue-engineering approaches. This study aims to estimate the global status and current trends in the field of cartilage tissue engineering. Methods: Publications from 2011 to 2020 on tissue engineering for cartilage repair and regeneration were retrieved from Web of Science Core Collection database. The source data were statistically evaluated based on the bibliometrics. In terms of visualized analysis, some bibliometric indicators such as bibliographic coupling, co-citation, co-authorship and co-occurrence analysis were performed by VOSviewer software, to investigate the research trends in tissue engineering for cartilage repair and regeneration. Results: In total, 3715 papers were included. Since 2011, the amount of issued papers and relative research interest (RRI) have grown by leaps and bounds globally. The United States was the biggest contributor to the research in this field, due to the greatest citation frequency, the highest H index and the strongest total link strength. Romania had the highest average citation for each. The journal Tissue Engineering Part A published most articles in this field. For institutions, the largest contributors were Shanghai Jiaotong University, University of California System and Sichuan University. Studies could all be grouped into four main clusters: study of biomaterial scaffolds, study of seeding cells and growth factors, experimental animal model and clinical study, and mechanism research. Conclusion: Great efforts should be put into the study of biomaterial scaffolds, seeding cells and growth factors, considered to be the next hot topics in cartilage tissue engineering. This findings provide collaborative insights and research orientation for academic researchers, surgeons and healthcare practitioners to a certain extent. [ABSTRACT FROM AUTHOR]

Purpose: This paper explores the feasibility of a new therapy for the treatment of hypospadias patients. Hypospadias is a very common congenital malformation of male genitals, with very high rate of recurrences after surgery. The field of regenerative medicine, which offers innovative solutions for many pathologies, still does not offer reliable solution for this pathology. Here, we propose quality, safety, and clinical feasibility assessment for an oral mucosa advanced therapy medicinal product (ATMP) grown on a biocompatible scaffold for a clinical study on urethral reconstruction of hypospadias patients. Methods: Urethral and oral mucosal epithelia from donor biopsies were cultivated between two fibrin layers, under clinical-grade conditions for cell and tissue characterization and comparison, aimed at tissue engineering. In addition, single-clone analyses were performed to analyze gene expression profiles of the two epithelia by microarray technology. Results: Oral mucosa appeared suitable for urethral reconstruction. The resulting ATMP was proven to maintain stem cells and regenerative potency. The preclinical safety studies were performed on human tissues to assess abnormalities and tumorigenicity, and confirmed the safety of the ATMP. Finally, the patient selection and the clinical protocol for the upcoming clinical trial were defined. Conclusions: Against this backdrop, in this paper, we are proposing a new reproducible and reliable ATMP for the treatment of hypospadias. [ABSTRACT FROM AUTHOR]

Purpose: In recent pre-clinical studies, biomaterials and bladder tissue engineering have shown promising outcomes when addressing the need for bladder tissue replacement. To date, multiple clinical experiences have been reported. Herein, we aim to review and summarize the reported clinical experience of biomaterial usage and tissue engineering of the urinary bladder. Methods: A systematic literature search was performed on Feb 2019 to identify clinical reports on biomaterials for urinary bladder replacement or augmentation and clinical experiences with bladder tissue engineering. We identified and reviewed human studies using biomaterials and tissue-engineered bladder as bladder substitutes or augmentation implants. The studies were then summarized for each respective procedure indication, technique, follow-up period, outcome, and important findings of the studies. Results: An extensive literature search identified 25 studies of case reports and case series with a cumulative clinical experience of 222 patients. Various biomaterials and tissue-engineered bladder were used, including plastic/polyethylene mold, preserved dog bladder, gelatine sponge, Japanese paper with Nobecutane, lypholized human dura, bovine pericardium, amniotic membrane, small intestinal mucosa, and bladder tissue engineering with autologous cell-seeded biodegradable scaffolds. However, overall clinical experiences including the outcomes and safety reports were not satisfactory enough to replace enterocystoplasty. Conclusion: To date, several clinical experiences of biomaterials and tissue-engineered bladder have been reported; however, various studies have reported non-satisfactory outcomes. Further technological advancements and a better understanding is needed to advance bladder tissue engineering as a future promising management option for patients requiring bladder drainage. [ABSTRACT FROM AUTHOR]

Appropriate scaffolds for tissue-engineered bone not only require mechanical strength, but also conditions that promote new bone growth. Bone tissue engineering scaffolds should establish the internal pore structure of the scaffolds and promote new bone growth. Additive manufacturing technology is widely used in the field of bone tissue engineering because it can directly and accurately construct the pore structure in 3D space, ensure internal connectivity of the scaffolds, and directly use biological materials. This paper reviews the development of additive manufacturing technology for bone tissue engineering. The differences between various additive manufacturing technologies are reviewed, with emphasis on the application of new technologies and materials. This paper also reviews the modeling processes used in bone tissue engineering, with emphasis on the optimization of the architectural design to achieve gradient structure and improved porosity and mechanical properties. Finally, this paper summarizes the 3D bioprinting technology that has fluid containing nutrients, matrix, and cells as constituent materials. Current problems and directions for the future development of additive manufacturing technology in the field of bone tissue engineering are also discussed. [ABSTRACT FROM AUTHOR]

In recent years, biomaterial- and scaffold-based immunomodulation strategies were implemented in tissue regeneration efforts for manipulating macrophage polarization (a.k.a. phenotype or lineage commitment, or differentiation). Yet, most of our understanding of macrophage phenotype commitment and phagocytic capacity is limited to how physical cues (extracellular matrix stiffness, roughness, and topography) and soluble chemical cues (cytokines and chemokines released from the scaffold) influence macrophage polarization. In the context of immune response–tissue interaction, the mechanical cues experienced by the residing cells within the tissue also play a critical role in macrophage polarization and inflammatory response. However, there is no compiled study discussing the effect of the dynamic mechanical environment around the tissues on macrophage polarization and the innate immune response. The aim of this comprehensive review paper is 2-fold; (a) to highlight the importance of mechanical cues on macrophage lineage commitment and function and (b) to summarize the important studies dedicated to understand how macrophage polarization changes with different mechanical loading modalities. For the first time, this review paper compiles and compartmentalizes the studies investigating the role of dynamic mechanical loading with various modalities, amplitude, and frequency on macrophage differentiation. A deeper understanding of macrophage phenotype in mechanically dominant tissues (i.e. musculoskeletal tissues, lung tissues, and cardiovascular tissues) provides mechanistic insights into the design of mechano-immunomodulatory tissue scaffold for tissue regeneration. [ABSTRACT FROM AUTHOR]

Recent years have seen the emergence of tissue engineering strategies as a means to overcome some of the limits of conventional medical treatment. A biomaterial with tailored physio-chemical characteristics is used in this sophisticated method to transport stem cells and growth factors/bioactive substances, or to attract local endogenous cells, enabling new tissue formation. Biomaterials might serve as a biomimetic structure inspired by the natural milieu, assisting the cells in establishing their natural relationships. Such a method would benefit from having ready access to an abundant reservoir of stem cells with strong tissue regeneration capacity, in addition to using biological compatible material to promote new tissue creation. Teeth may have a plethora of self-renewing, multipotent mesenchymal stem cell (MSC) populations. Recent advancements and promising directions for cell transplantation and homing techniques using dental MSCs for tissue regeneration are discussed in this review paper. Overall, this research paints a picture of the present landscape of new approaches to using tooth-derived MSCs in conjunction with biomaterials and bioactive substances for tissue regeneration. [ABSTRACT FROM AUTHOR]

Collagen extracted from fishes has been appearing as an alternative for commercial porcine and bovine collagen and it has been considered interesting especially for membrane manufacturing in tissue engineering. Despite the positive in vitro effects of fish collagen membranes, there is still no understanding of all the benefits that this natural biomaterial plays in the wound healing process, due to the lack of compilation of the results obtained in animal studies. In this sense, the purpose of this study was to perform a systematic review of the literature to examine the effects of fish collagen membranes for skin wound healing in experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "fish," collagen," "skin," and "in vivo". A total of 10 articles were retrieved from the databases PubMed and Scopus. After the elegibility analyses, this review covers the different origins of fish collagen reported in the different papers from the beginning of 2015 through the middle of 2021. The results were based mainly on histological analysis and macroscopic evaluation, and fish skin collagen was responsible for improving the wound healing rate and the process of reepithelization and collagen deposition. In conclusion, fish skin collagen has shown positive results in in vivo studies and may be a potential biomaterial in tissue engineering. [ABSTRACT FROM AUTHOR]

Biological tissues are composed of cells surrounded by the extracellular matrix (ECM). The ECM can be thought of as a fibrous polymer network, acting as a natural scaffolding to provide mechanical support to the cells. Reciprocal mechanical and chemical interactions between the cells and the ECM are crucial in regulating the development of tissues and maintaining their functionality. Hence, to maintain in vivo-like behaviour when cells are cultured in vitro, they are often seeded in a gel, which aims to mimic the ECM. In this paper, we present a mathematical model that incorporates cell-gel interactions together with osmotic pressure to study the mechanical behaviour of biological gels. In particular, we consider an experiment where cells are seeded within a gel, which gradually compacts due to forces exerted on it by the cells. Adopting a one-dimensional Cartesian geometry for simplicity, we use a combination of analytical techniques and numerical simulations to investigate how cell traction forces interact with osmotic effects (which can lead to either gel swelling or contraction depending on the gel’s composition). Our results show that a number of qualitatively different behaviours are possible, depending on the composition of the gel (i.e. its chemical potentials) and the strength of the cell traction forces. A novel prediction of our model is that there are cases where the gel oscillates between swelling and contraction; to our knowledge, this behaviour has not been reported in experiments. We also consider how physical parameters like drag and viscosity affect the manner in which the gel evolves. [ABSTRACT FROM AUTHOR]

Once cartilage is damaged, its self-repair capacity is very limited. The strategy of tissue engineering has brought a new idea for repairing cartilage defect and cartilage regeneration. In particular, nasal cartilage regeneration is a challenge because of the steady increase in nasal reconstruction after oncologic resection, trauma, or rhinoplasty. From this perspective, three-dimensional (3D) printing has emerged as a promising technology to address the complexity of nasal cartilage regeneration, using patient's image data and computer-aided deposition of cells and biomaterials to precisely fabricate complex, personalized tissue-engineered constructs. In this review, we summarized the major progress of three prevalent 3D printing approaches, including inkjet-based printing, extrusion-based printing and laser-assisted printing. Examples are highlighted to illustrate 3D printing for nasal cartilage regeneration, with special focus on the selection of seeded cell, scaffolds and growth factors. The purpose of this paper is to systematically review recent research about the challenges and progress and look forward to the future of 3D printing techniques for nasal cartilage regeneration. Level of Evidence III This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266. [ABSTRACT FROM AUTHOR]

This study examines China's performance on tissue engineering using scientometrics measures such as China's global publication share, rank, growth rate and citation impact, its publications in various sub-fields, top journals in terms of national share based on last 5 years (2008-2012) publications data obtained from ISI Science citation index expanded database. We have also determined Chinese share with international collaborative papers at the national level, as well as h-core papers and high-cited papers, etc. [ABSTRACT FROM AUTHOR]

The advent of the Three-Dimensional (3D) printing technique, as an Additive Manufacturing technology, made the manufacture of complex porous scaffolds plausible in the tissue engineering field. In Fused Deposition Modeling based 3D printing, layer upon layer deposition of filaments produces voids and gaps, leading to a crack generation and loose bonding. Cohesive zone model (CZM), a fracture mechanics concept, is a promising theory to study the layers bond behavior. In this paper, a combination of experimental and computational investigations was proposed to obtain bond parameters and evaluate the effect of porosity and microstructure on these parameters. First, we considered two different designs for scaffolds beside a non-porous Bulk design. Then, we performed Double cantilever beam and Singe Lap Shear tests on the 3D printed samples for Modes I and II, respectively. Afterward, we developed the numerical simulations of these tests using the Finite element method (FEM) to obtain CZM bond parameters. Results demonstrate that the initial stiffness and cohesive strength were pretty similar for all designs in Mode I. However, the cohesive energy for the Bulk sample was approximately four times of porous samples. Furthermore, for Mode II, the initial stiffness and cohesive energy of the Bulk model were five and four times of porous designs while their cohesive strengths were almost the same. Also, using cohesive parameters was significantly enhanced the accuracy of FEM predictions in comparison with fully bonded assumption. It can be concluded that for the numerical analysis of 3D printed parts mechanical behavior, it is necessary to obtain and suppose the cohesive parameters. The present work illustrates the effectiveness of CZM and FEM combination to obtain the layer adhesive parameters of the 3D printed scaffold. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) synthesized by Komagataeibacter hansenii is a polymer that recently gained an attention of tissue engineers, since its features make it a suitable material for scaffolds production. Nevertheless, it is still necessary to modify BNC to improve its properties in order to make it more suitable for biomedical use. One approach to address this issue is to genetically engineer K. hansenii cells towards synthesis of BNC with modified features. One of possible ways to achieve that is to influence the bacterial movement or cell morphology. In this paper, we described for the first time, K. hansenii ATCC 23769 motA+ and motB+ overexpression mutants, which displayed elongated cell phenotype, increased motility, and productivity. Moreover, the mutant cells produced thicker ribbons of cellulose arranged in looser network when compared to the wild-type strain. In this paper, we present a novel development in obtaining BNC membranes with improved properties using genetic engineering tools. [ABSTRACT FROM AUTHOR]

Calcium carbonate micro- and nanoparticles are considered as chemically inert materials. Therefore, they are widely considered in the field of biosensing, drug delivery, and as filler material in plastic, paper, paint, sealant, and adhesive industries. The unusual properties of calcium carbonate-based nanomaterials, such as biocompatibility, high surface-to-volume ratio, robust nature, easy synthesis, and surface functionalization, and ability to exist in a variety of morphologies and polymorphs, make them an ideal candidate for both industrial and biomedical applications. Significant research efforts have been devoted for developing novel synthesis methods of calcium carbonate particles in micrometer and nanometer dimensions. This review highlights different approaches of the synthesis of calcium carbonate micro- and nanoparticles, such as precipitation, slow carbonation, emulsion, polymer-mediated method, including in-situ polymerization, mechano-chemical, microwave-assisted method, and biological methods. The applications of these versatile calcium carbonate micro- and nanoparticles in the biomedical field (such as in drug delivery, therapeutics, tissue engineering, antimicrobial activity, biosensing applications), in industries, and environmental sector has also been comprehensively covered. [ABSTRACT FROM AUTHOR]

Soft biological tissues compromise diverse cell types and extracellular matrix constituents, each of which can possess individual natural configurations, material properties, and rates of turnover. For this reason, mixture-based models of growth (changes in mass) and remodeling (change in microstructure) are well-suited for studying tissue adaptations, disease progression, and responses to injury or clinical intervention. Such approaches also can be used to design improved tissue engineered constructs to repair, replace, or regenerate tissues. Focusing on blood vessels as archetypes of soft tissues, this paper reviews a constrained mixture theory introduced twenty years ago and explores its usage since by contrasting simulations of diverse vascular conditions. The discussion is framed within the concept of mechanical homeostasis, with consideration of solid-fluid interactions, inflammation, and cell signaling highlighting both past accomplishments and future opportunities as we seek to understand better the evolving composition, geometry, and material behaviors of soft tissues under complex conditions. [ABSTRACT FROM AUTHOR]

A rapid revolution in the medical health care sector is expected due to the use of medical products fabricated from 3D printer technology. Several researches have been carried on the innovative achievements of biomaterials using 3D printing. This advancement in biomaterials leads to an increasing trend in the use of 3D printer even in medical research. During 3D printing, the materials are transformed into desired shape with the application of heat, laser, or other energies. Hence, as per the mechanical property, materials react towards the external energy to define the design capability. 3D printing technology has the ability to convert the two-dimensional image obtained from non-invasive scanning imaging of human body, i.e., computed tomography (CT) or magnetic resonance imaging (MRI) scan into a 3D digital model of any shape. The combined uses of biomaterials and 3D printing technologies have made significant improvement in the field of tissue engineering. Due to shortage of donor organs and also lack of facility to preserve them leads to the demand of artificial tissues. In this review paper, we firstly introduce about the various types of conventional and recent 3D printing technologies, biomaterials, and additives which changes its physical properties. And finally, summarize the applications of 3D printing technique in medical applications. There is the possibility to increase resolution and print single cell layer using piezoelectric transducer at the printer head in FDM-based printing technique which is described as the proposed technique in the paper. [ABSTRACT FROM AUTHOR]

Tissue engineering (TE) is an integrated discipline that involves engineering and natural science in the development of biological materials to replace, repair, and improve the function of diseased or missing tissues. Traditional medical and surgical treatments have been reported to have side effects on patients caused by organ necrosis and tissue loss. However, engineered tissues and organs provide a new way to cure specific diseases. Scaffold fabrication is an important step in the TE process. This paper summarizes and reviews the widely used scaffold fabrication methods, including conventional methods, electrospinning, three-dimensional printing, and a combination of molding techniques. Furthermore, the differences among the properties of tissues, such as pore size and distribution, porosity, structure, and mechanical properties, are elucidated and critically reviewed. Some studies that combine two or more methods are also reviewed. Finally, this paper provides some guidance and suggestions for the future of scaffold fabrication. [ABSTRACT FROM AUTHOR]