scholarly journals Nanotechnological Strategies for Biofabrication of Human Organs

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Rodrigo A. Rezende ◽  
Fábio de Souza Azevedo ◽  
Frederico David Pereira ◽  
Vladimir Kasyanov ◽  
Xuejun Wen ◽  
...  
Keyword(s):  
Vascular Graft ◽  
Magnetic Levitation ◽  
Building Blocks ◽  
One Dimension ◽  
Intermediate Structure ◽  
Human Tissues ◽  
Robotic Device ◽  
Future Prospects ◽  
Self Assembling

Nanotechnology is a rapidly emerging technology dealing with so-called nanomaterials which at least in one dimension have size smaller than 100 nm. One of the most potentially promising applications of nanotechnology is in the area of tissue engineering, including biofabrication of 3D human tissues and organs. This paper focused on demonstrating how nanomaterials with nanolevel size can contribute to development of 3D human tissues and organs which have macrolevel organization. Specific nanomaterials such as nanofibers and nanoparticles are discussed in the context of their application for biofabricating 3D human tissues and organs. Several examples of novel tissue and organ biofabrication technologies based on using novel nanomaterials are presented and their recent limitations are analyzed. A robotic device for fabrication of compliant composite electrospun vascular graft is described. The concept of self-assembling magnetic tissue spheroids as an intermediate structure between nano- and macrolevel organization and building blocks for biofabrication of complex 3D human tissues and organs is introduced. The design of in vivo robotic bioprinter based on this concept and magnetic levitation of tissue spheroids labeled with magnetic nanoparticles is presented. The challenges and future prospects of applying nanomaterials and nanotechnological strategies in organ biofabrication are outlined.

scholarly journals De novo design of self-assembling helical protein filaments

Science ◽  
2018 ◽  
Vol 362 (6415) ◽  
pp. 705-709 ◽  
Author(s):  
Hao Shen ◽  
Jorge A. Fallas ◽  
Eric Lynch ◽  
William Sheffler ◽  
Bradley Parry ◽  
...  
Keyword(s):  
De Novo ◽  
Computational Design ◽  
Building Blocks ◽  
Repeat Units ◽  
Self Assembling ◽  
Wide Range ◽  
Helical Protein ◽  
Monomeric Proteins

We describe a general computational approach to designing self-assembling helical filaments from monomeric proteins and use this approach to design proteins that assemble into micrometer-scale filaments with a wide range of geometries in vivo and in vitro. Cryo–electron microscopy structures of six designs are close to the computational design models. The filament building blocks are idealized repeat proteins, and thus the diameter of the filaments can be systematically tuned by varying the number of repeat units. The assembly and disassembly of the filaments can be controlled by engineered anchor and capping units built from monomers lacking one of the interaction surfaces. The ability to generate dynamic, highly ordered structures that span micrometers from protein monomers opens up possibilities for the fabrication of new multiscale metamaterials.

scholarly journals From nano to macro: Enabling Nanotechnologies for Human Organ Biofabrication (Electrospun Nanofibers and Hybrid Technique)

2018 ◽  
Vol 1 (1) ◽  
pp. 41 ◽  
Author(s):  
Rodrigo Alvarenga Rezende ◽  
Marcos Antonio Sabino ◽  
Janaína De Andréa Dernowsek ◽  
Fábio De Albuquerque Vilalba ◽  
Vladimir Mironov ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Electrospun Nanofibers ◽  
Building Blocks ◽  
Hybrid Technique ◽  
Human Tissues ◽  
Scale Level ◽  
Human Organ ◽  
3D Structures ◽  
Self Assembling ◽  
Dual Scale

This review proposes to present how materials at nanolevel scale can contribute to the development of three-dimensional (3D) structures, human tissues, and organs which have macrolevel organization. Specific nanomaterials such as nanofibers and nanoparticles are presented and discussed in their application for biofabricating 3D human tissues and organs. The concept of self-assembling magnetic tissue spheroids as an intermediate mesolevel structure between nano and macrolevel organization and building blocks for biofabrication in dual scale level of complex 3D human tissues and organs is detached. The challenges and perspectives of employing nanomaterials and nanotechnological strategies in the biofabrication were also traced.

In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin
Keyword(s):  
Vascular Graft ◽  
Graft Infection ◽  
Vascular Graft Infection ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Prosthetic Vascular Graft Infection ◽  
Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

Combinatorial Peptide Libraries for Selecting Inorganic-Binding Proteins: A Step in Molecular Biomimetics

2003 ◽  
Vol 773 ◽  
Author(s):  
C. Tamerler ◽  
S. Dinçer ◽  
D. Heidel ◽  
N. Karagûler ◽  
M. Sarikaya
Keyword(s):  
Binding Proteins ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Inorganic Materials ◽  
Combinatorial Peptide Libraries ◽  
Self Assembling ◽  
Complex Functions ◽  
Recent Developments ◽  
Specific Proteins ◽  
Molecular Biomimetics

AbstractProteins, one of the building blocks in organisms, not only control the assembly in biological systems but also provide most of their complex functions. It may be possible to assemble materials for practical technological applications utilizing the unique advantages provided by proteins. Here we discuss molecular biomimetic pathways in the quest for imitating biology at the molecular scale via protein engineering. We use combinatorial biology protocols to select short polypeptides that have affinity to inorganic materials and use them in assembling novel hybrid materials. We give an overview of some of the recent developments of molecular engineering towards this goal. Inorganic surface specific proteins were identified by using cell surface and phage display technologies. Examples of metal and metal oxide specific polypeptides were represented with an emphasis on certain level of specificities. The recognition and self assembling characteristics of these inorganic-binding proteins would be employed in develeopment of hybrid multifunctional materials for novel bio- and nano-technological applications.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

Kinase Targets for Mycolic Acid Biosynthesis in Mycobacterium tuberculosis

2019 ◽  
Vol 12 (1) ◽  
pp. 27-49 ◽  
Author(s):  
Shahinda S.R. Alsayed ◽  
Chau C. Beh ◽  
Neil R. Foster ◽  
Alan D. Payne ◽  
Yu Yu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Enzymatic Activity ◽  
Bacterial Pathogen ◽  
Building Blocks ◽  
Mycolic Acid ◽  
Adaptive Responses ◽  
Mycolic Acids ◽  
Hydroxylated Fatty Acids

Background:Mycolic acids (MAs) are the characteristic, integral building blocks for the mycomembrane belonging to the insidious bacterial pathogen Mycobacterium tuberculosis (M.tb). These C60-C90 long α-alkyl-β-hydroxylated fatty acids provide protection to the tubercle bacilli against the outside threats, thus allowing its survival, virulence and resistance to the current antibacterial agents. In the post-genomic era, progress has been made towards understanding the crucial enzymatic machineries involved in the biosynthesis of MAs in M.tb. However, gaps still remain in the exact role of the phosphorylation and dephosphorylation of regulatory mechanisms within these systems. To date, a total of 11 serine-threonine protein kinases (STPKs) are found in M.tb. Most enzymes implicated in the MAs synthesis were found to be phosphorylated in vitro and/or in vivo. For instance, phosphorylation of KasA, KasB, mtFabH, InhA, MabA, and FadD32 downregulated their enzymatic activity, while phosphorylation of VirS increased its enzymatic activity. These observations suggest that the kinases and phosphatases system could play a role in M.tb adaptive responses and survival mechanisms in the human host. As the mycobacterial STPKs do not share a high sequence homology to the human’s, there have been some early drug discovery efforts towards developing potent and selective inhibitors.Objective:Recent updates to the kinases and phosphatases involved in the regulation of MAs biosynthesis will be presented in this mini-review, including their known small molecule inhibitors.Conclusion:Mycobacterial kinases and phosphatases involved in the MAs regulation may serve as a useful avenue for antitubercular therapy.

scholarly journals A therapeutic vascular conduit to support in vivo cell-secreted therapy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Edward X. Han ◽  
Hong Qian ◽  
Bo Jiang ◽  
Maria Figetakis ◽  
Natalia Kosyakova ◽  
...  
Keyword(s):  
Vascular Graft ◽  
Large Scale ◽  
Biological Effects ◽  
Therapeutic Protein ◽  
Close Proximity ◽  
Delivery Platform ◽  
Stage Renal Disease ◽  
End Stage

AbstractA significant barrier to implementation of cell-based therapies is providing adequate vascularization to provide oxygen and nutrients. Here we describe an approach for cell transplantation termed the Therapeutic Vascular Conduit (TVC), which uses an acellular vessel as a scaffold for a hydrogel sheath containing cells designed to secrete a therapeutic protein. The TVC can be directly anastomosed as a vascular graft. Modeling supports the concept that the TVC allows oxygenated blood to flow in close proximity to the transplanted cells to prevent hypoxia. As a proof-of-principle study, we used erythropoietin (EPO) as a model therapeutic protein. If implanted as an arteriovenous vascular graft, such a construct could serve a dual role as an EPO delivery platform and hemodialysis access for patients with end-stage renal disease. When implanted into nude rats, TVCs containing EPO-secreting fibroblasts were able to increase serum EPO and hemoglobin levels for up to 4 weeks. However, constitutive EPO expression resulted in macrophage infiltration and luminal obstruction of the TVC, thus limiting longer-term efficacy. Follow-up in vitro studies support the hypothesis that EPO also functions to recruit macrophages. The TVC is a promising approach to cell-based therapeutic delivery that has the potential to overcome the oxygenation barrier to large-scale cellular implantation and could thus be used for a myriad of clinical disorders. However, a complete understanding of the biological effects of the selected therapeutic is absolutely essential.

scholarly journals Tumor-associated macrophages: potential therapeutic strategies and future prospects in cancer

2021 ◽  
Vol 9 (1) ◽  
pp. e001341
Author(s):  
Chunxiao Li ◽  
Xiaofei Xu ◽  
Shuhua Wei ◽  
Ping Jiang ◽  
Lixiang Xue ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Progression ◽  
Cancer Cells ◽  
Poor Prognosis ◽  
Tumor Immunotherapy ◽  
Therapeutic Strategies ◽  
Preclinical Studies ◽  
Future Prospects ◽  
Tumor Associated Macrophages

Macrophages are the most important phagocytes in vivo. However, the tumor microenvironment can affect the function and polarization of macrophages and form tumor-associated macrophages (TAMs). Usually, the abundance of TAMs in tumors is closely associated with poor prognosis. Preclinical studies have identified important pathways regulating the infiltration and polarization of TAMs during tumor progression. Furthermore, potential therapeutic strategies targeting TAMs in tumors have been studied, including inhibition of macrophage recruitment to tumors, functional repolarization of TAMs toward an antitumor phenotype, and other therapeutic strategies that elicit macrophage-mediated extracellular phagocytosis and intracellular destruction of cancer cells. Therefore, with the increasing impact of tumor immunotherapy, new antitumor strategies to target TAMs are now being discussed.

scholarly journals A molecular architectural design that promises potent antimicrobial activity against multidrug-resistant pathogens

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Bing Yuan ◽  
Jiaojiao Liu ◽  
Zhixiong Deng ◽  
Lin Wei ◽  
Wenwen Li ◽  
...  
Keyword(s):  
Architectural Design ◽  
Building Blocks ◽  
Multidrug Resistant ◽  
In Vitro Cytotoxicity ◽  
Antimicrobial Drugs ◽  
Minimal Inhibitory Concentrations ◽  
Antimicrobial Efficiency ◽  
Multidrug Resistant Pathogens

AbstractAddressing the devastating threat of drug-resistant pathogens requires the discovery of new antibiotics with advanced action mechanisms and/or novel strategies for drug design. Herein, from a biophysical perspective, we design a class of synthetic antibacterial complexes with specialized architectures based on melittin (Mel), a natural antimicrobial peptide, and poly(ethylene glycol) (PEG), a clinically available agent, as building blocks that show potent and architecture-modulated antibacterial activity. Among the complexes, the flexibly linear complex consisting of one Mel terminally connected with a long-chained PEG (e.g., PEG12k–1*Mel) shows the most pronounced improvement in performance compared with pristine Mel, with up to 500% improvement in antimicrobial efficiency, excellent in vitro activity against multidrug-resistant pathogens (over a range of minimal inhibitory concentrations of 2–32 µg mL−1), a 68% decrease in in vitro cytotoxicity, and a 57% decrease in in vivo acute toxicity. A lipid-specific mode of action in membrane recognition and an accelerated “channel” effect in perforating the bacterial membrane of the complex are described. Our results introduce a new way to design highly efficient and low-toxicity antimicrobial drugs based on architectural modulations with clinically available agents.

scholarly journals Synthesis, Characterization and Evaluation of Peptide Nanostructures for Biomedical Applications

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4587
Author(s):  
Fanny d’Orlyé ◽  
Laura Trapiella-Alfonso ◽  
Camille Lescot ◽  
Marie Pinvidic ◽  
Bich-Thuy Doan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biomedical Applications ◽  
Chemical Reactivity ◽  
Physical Stability ◽  
Chemical Properties ◽  
Building Blocks ◽  
Imaging Probes ◽  
Therapeutic Molecules

There is a challenging need for the development of new alternative nanostructures that can allow the coupling and/or encapsulation of therapeutic/diagnostic molecules while reducing their toxicity and improving their circulation and in-vivo targeting. Among the new materials using natural building blocks, peptides have attracted significant interest because of their simple structure, relative chemical and physical stability, diversity of sequences and forms, their easy functionalization with (bio)molecules and the possibility of synthesizing them in large quantities. A number of them have the ability to self-assemble into nanotubes, -spheres, -vesicles or -rods under mild conditions, which opens up new applications in biology and nanomedicine due to their intrinsic biocompatibility and biodegradability as well as their surface chemical reactivity via amino- and carboxyl groups. In order to obtain nanostructures suitable for biomedical applications, the structure, size, shape and surface chemistry of these nanoplatforms must be optimized. These properties depend directly on the nature and sequence of the amino acids that constitute them. It is therefore essential to control the order in which the amino acids are introduced during the synthesis of short peptide chains and to evaluate their in-vitro and in-vivo physico-chemical properties before testing them for biomedical applications. This review therefore focuses on the synthesis, functionalization and characterization of peptide sequences that can self-assemble to form nanostructures. The synthesis in batch or with new continuous flow and microflow techniques will be described and compared in terms of amino acids sequence, purification processes, functionalization or encapsulation of targeting ligands, imaging probes as well as therapeutic molecules. Their chemical and biological characterization will be presented to evaluate their purity, toxicity, biocompatibility and biodistribution, and some therapeutic properties in vitro and in vivo. Finally, their main applications in the biomedical field will be presented so as to highlight their importance and advantages over classical nanostructures.

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