New research in Science and Technology of Advanced Materials discovers that nanoscale manipulation on the surface of materials could stimulate cells to differentiate into specific tissues – eliminating the use of growth or transcription factors.
Researchers are trying to find ways to control cellular response in vitro using engineered materials in a continuous pursuit to regenerate injured or diseased tissues. Recent studies have found that nanoscale structure of the materials, on which such cells are cultured, affect how well they proliferate and develop into the tissues they are meant to become.
Scientists from the University of Malaya in Malaysia, Dr. Belinda Pingguan-Murphy et al., together with Prof. Sheikh Ali Akbar of Ohio State University, reviewed the most recent research on how the nanoscale topographies affect cellular regenerative responses.
For example, human fetal osteoblast cells that are involved in bone formation were found to grow better on materials that had tiny protrusions on their surfaces (11 nanometers in height) compared to surfaces that were either flat or had higher protrusions. They also attached better to surfaces with nanosized pits that were 14 nm or 29 nm deep compared to flat surfaces and surfaces with pits that were 45 nm deep.
Research has also found that the distance between pits or protrusions and whether they are random or highly ordered also affect how osteoblasts and stem cells respond. Additionally, nanoscale grooved surfaces trigger these cells to grow in the direction of the grooves.
Generally, when a material is exposed to a biological fluid, water molecules bind rapidly to the surface followed by the incorporation of chloride and sodium ions. Proteins then adsorb to this surface. The resulting mixture of proteins, as well as their three-dimensional shape and orientation with respect to the surface topography, sends signals to the cells influencing their attachment and spreading.
Further research in this area may lead to the development of clinical prostheses with topographies that can directly modulate stem cell fate, enabling cell growth and development to be tailored to a specific application without using potentially harmful chemicals, write the researchers in their review published in the journal of Science and Technology of Advanced Materials. However, developing low-cost, high-output fabrication techniques that allow for the development of specific nano-topographies is still a limiting factor.
Limb or organ regrowth may be hidden in our genes
If you trace our evolutionary tree way back to its roots — long before the shedding of gills or the development of opposable thumbs — you will likely find a common ancestor with the amazing ability to regenerate lost body parts. In an effort to understand what was lost, researchers have built a running list of the genes that enable regenerating animals to grow back a severed tail or repair damaged tissues.
A Duke study appearing April 6 in the journal Nature has discovered the presence of these regulatory sequences in zebrafish, a favored model of regeneration research. Called “tissue regeneration enhancer elements” or TREEs, these sequences can turn on genes in injury sites and even be engineered to change the ability of animals to regenerate.
UC San Francisco researchers have for the first time developed a method to precisely control embryonic stem cell differentiation with beams of light, enabling them to be transformed into neurons in response to a precise external cue.
“We’ve discovered a basic mechanism the cell uses to decide whether to pay attention to a developmental cue or to ignore it,” said senior author Matthew Thomson, PhD, a researcher in the department of Cellular and Molecular Pharmacology and the Center for Systems and Synthetic Biology at UCSF.
Thomson’s ambitious big idea is to use the light-inducible differentiation technology his group has developed to study how stem cells produce complex tissues in three dimensions. He imagines a day when researchers can illuminate a bath of undifferentiated stem cells with a pattern of different colors of light and come back the next day to find a complex pattern of blood and nerve and liver tissue forming an organ that can be transplanted into a patient.
Researchers in the United Kingdom and Malaysia are developing a new class of injectable material that stimulates stem cells to regenerate damaged tissue and form new blood vessels, heart and bone tissue.