Posts tagged artificial tissue
Articles and news from the latest research reports.
New 3D printing technique could speed up progress towards creation of artificial organs
In the more immediate future it could be used to generate biopsy-like tissue samples for drug testing. The technique relies on an adjustable “microvalve” to build up layers of human embryonic stem cells (hESCs).
Altering the nozzle diameter precisely controls the rate at which cells are dispensed.
Lead scientist Dr Will Shu, from Heriot-Watt University in Edinburgh, said: “We found that the valve-based printing is gentle enough to maintain high stem cell viability, accurate enough to produce spheroids of uniform size, and most importantly, the printed hESCs maintained their pluripotency - the ability to differentiate into any other cell type.”
Embryonic stem cells, which originate from early stage embryos, are blank slates with the potential to become any type of tissue in the body.
The research is reported in the journal Biofabrication.
In the long term, the new printing technique could pave the way for hESCs being incorporated into transplant-ready laboratory-made organs and tissues, said the researchers.
The 3D structures will also enable scientists to create more accurate human tissue models for drug testing.
Cloning technology can produce embryonic stem cells, or cells with ESC properties, containing a patient’s own genetic programming.
Artificial tissue and organs made from such cells could be implanted into the patient from which they are derived without triggering a dangerous immune response.
Jason King, business development manager of stem cell biotech company Roslin Cellab, which took part in the research, said: “Normally laboratory grown cells grow in 2D but some cell types have been printed in 3D. However, up to now, human stem cell cultures have been too sensitive to manipulate in this way.
"This is a scientific development which we hope and believe will have immensely valuable long-term implications for reliable, animal-free, drug testing, and, in the longer term, to provide organs for transplant on demand, without the need for donation and without the problems of immune suppression and potential organ rejection."
Precisely engineering 3-D brain tissues
Borrowing from microfabrication techniques used in the semiconductor industry, MIT and Harvard Medical School (HMS) engineers have developed a simple and inexpensive way to create three-dimensional brain tissues in a lab dish.
The new technique yields tissue constructs that closely mimic the cellular composition of those in the living brain, allowing scientists to study how neurons form connections and to predict how cells from individual patients might respond to different drugs. The work also paves the way for developing bioengineered implants to replace damaged tissue for organ systems, according to the researchers.
"We think that by bringing this kind of control and manipulation into neurobiology, we can investigate many different directions," says Utkan Demirci, an assistant professor in the Harvard-MIT Division of Health Sciences and Technology (HST).
Demirci and Ed Boyden, associate professor of biological engineering and brain and cognitive sciences at MIT’s Media Lab and McGovern Institute, are senior authors of a paper describing the new technique, which appears in the Nov. 27 online edition of the journal Advanced Materials. The paper’s lead author is Umut Gurkan, a postdoc at HST, Harvard Medical School and Brigham and Women’s Hospital.
(Source: eurekalert.org)
Harvard scientists have created a type of cyborg tissue by embedding a three-dimensional network of functional, biocompatible, nanoscale wires into engineered human tissues.
The research addresses a concern that has long been associated with work on bioengineered tissue: how to create systems capable of sensing chemical or electrical changes in the tissue after it has been grown and implanted. The system might also represent a solution to researchers’ struggles in developing methods to directly stimulate engineered tissues and measure cellular reactions.
The process of building the networks is similar to that used to etch microchips. Beginning with a two-dimensional substrate, researchers laid out a mesh of organic polymer around nanoscale wires, which serve as the critical sensing elements. Nanoscale electrodes, which connect the nanowire elements, were then built within the mesh to enable nanowire transistors to measure the activity in cells without damaging them. Once completed, the substrate is then dissolved, leaving researchers with a netlike sponge, or a mesh, that can be folded or rolled into a host of three-dimensional shapes. Finally, the networks are porous enough to allow seeding them with cells and encourage those cells to grow in 3-D cultures.
Using heart and nerve cells, the Harvard research team successfully engineered tissues containing embedded nanoscale networks without affecting the cells’ viability or activity. Using the embedded devices, the researchers were then able to detect electrical signals generated by cells deep within the tissue, and to measure changes in those signals in response to cardio- or neuro-stimulating drugs.