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Posts Tagged ‘3-hydroxypropionic acid’


3D BioPrinted Carbon Nanotubes used to Stimulate Bone Regrowth

Reporter: Irina Robu, PhD

Bone disorders are of significant concern due to increase in the median age of our population and at this present time bone grafts have are used to restore damaged bone. However, synthetic biomaterials are now being used as bone graft substitutes and they are selected for structural restoration based on their biomechanical properties. Lately, scaffolds are engineered to be bioactive to enhance tissue growth. These scaffolds are usually porous, made of biodegradable factors, drugs or stem cells.

The research group led by Dr. Maria Vallet-Regi at Faculty of Pharmacy-Universidad Complutense de Madrid showed that carbon nanotubes to the mix to create 3D electrical network within the bone tissue can stimulate bone cell regrowth. The polymer they used was polycarpolactone (PCL), which is rather easy to 3D print.
According to Mercedes Vila, the Principal Investigator in charge of the project, the carbon nanotubes were added to the bio-printable material mixture to create a three-dimensional electrical conducting network all through the volume of the scaffold, which would allow the application of this stimulation to the scaffold once implanted on the damaged bone site.
“In this sense, electrical stimulation has been explored since the discovery of the presence of electrical potentials in mechanically loaded bones,” Mercedes pointed out. “Certain types of cell behavior, such as adhesion and differentiation, can be affected by the application of electrical stimulation. Thus, the creation of a permanent charge on the material surface, positive or negative, as well as a direct electrical stimulation can promote the attraction of charged ions from the environment to the cells. This would modify their protein adsorption with the subsequent influence on the cells’ metabolic activity. Therefore, the use of electrical stimulation after biomaterial implantation to favor cell adhesion and differentiation and, consequently, induce bone healing seems a smart approach to accelerate the osteointegration process.”

Adding CNTs into the bio-printed polymer and mineral prosthetic bone can stimulate regrowth of the actual bone cells. However, bio-printing CNTs created no extra difficulties, as they are so thin that they can be extruded with ease through any pneumatic syringe. Most of the complications are related to finding the correct viscosity in the combination of CPL and hydroxypatite.

“Finding the right right viscosity to be extruded through the syringe while keeping enough robustness to get the 3D scaffold printed at room temperature, was complicated,” Mercedes admitted. “At the same time as the slurry was prepared in dichloromethane solution for diluting the PCL, achieving the right viscosity while evaporating the solvent was tricky. Moreover, once the PCL and the hydroxyapatite were mixed together, the addition of the CNTs was performed and reaching a proper dispersion took a bit of stirring time.”

Using EnvisionTEC’s 3D bioplotter, the researchers were able to create very complex 3D structures which would enhance the future for tissue replacements as it allows tailored solutions by capturing the anatomical information of the patient’s wound by computed tomography and magnetic resonance, for example, to obtain a personalized and unique implant.

As with many other 3D printing applications, it appears we are only starting to scratch the surface of the possibilities that are ahead for bioprinting.

Source

https://lockerdome.com/3dprintingindustry/8020474642838036

Other related articles published in this Open Access Online Scientific Journal include the following:

search for Bone related articles, please place here references

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

Conventional tumor markers are unsuitable for detecting carcinoma at an early stage and lack clinical efficacy and utility. Multiple classification analysis revealed that the variations in the levels of malonic acid and L-serine largely contributed to the separation of esophageal cancer; gastric cancer was characterized by changes in the levels of 3-hydroxypropionic acid and pyruvic acid; and L-alanine, glucuronoic lactone and L-glutamine contributed to the separation of colorectal cancer. Some metabolites are more sensitive for detecting gastrointestinal cancer than conventional biomarkers and thus metabolomics has the potential as an early diagnostic tool for cancer. Studies also showed that global metabolic profiling of colon mucosae would define metabolic signatures that not only discriminate malignant from normal mucosae, but also could distinguish the anatomical and clinicopathological characteristics of colorectal cancer. Thus it is suggested that metabolic profiling of colorectal cancer mucosae could provide new phenotypic biomarkers for colorectal cancer management.

A full spectrum of metabolic aberrations that are directly linked to colorectal cancer at early curable stages is critical for developing and deploying molecular diagnostic and therapeutic approaches that will significantly improve patient survival. A number of dysregulated metabolic pathways, such as glycolysis, tricarboxylic acid cycle, urea cycle, pyrimidine metabolism, tryptophan metabolism, polyamine metabolism, as well as gut microbial-host co-metabolism in colorectal cancer subjects are reported. Significantly increased tryptophan metabolism, and disturbed tricarboxylic acid cycle and the gut microflora metabolism were observed in the colorectal cancer patients. The urinary metabolite profile of postoperative colorectal cancer subjects altered significantly from that of the preoperative stage. The significantly down-regulated gut microflora metabolism and tricarboxylic acid cycle were observed in postoperative colorectal cancer subjects, presumably due to the colon flush involved in the surgical procedure and weakened physical conditions of the patients. The expression of 5-hydroxytryptophan significantly decreased in postsurgery cases, suggesting a recovered tryptophan metabolism toward healthy state. Abnormal histamine metabolism and glutamate metabolism were found only in the urine samples of colorectal cancer patients. There are distinct urinary metabolic footprints of colorectal cancer patients characterized by altered levels of metabolites derived from gut microbial-host co-metabolism. A panel of metabolite markers composed of citrate, hippurate, p-cresol, 2-aminobutyrate, myristate, putrescine, and kynurenate was able to discriminate colorectal cancer subjects from their healthy counterparts. These potential metabolite markers provide a novel and promising molecular diagnostic approach for the early detection of colorectal cancer.

Source References:

http://www.ncbi.nlm.nih.gov/pubmed/21773981

http://www.ncbi.nlm.nih.gov/pubmed/22792336

http://www.ncbi.nlm.nih.gov/pubmed/19063642

http://www.ncbi.nlm.nih.gov/pubmed/20121166

http://www.ncbi.nlm.nih.gov/pubmed/22148915

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