Researchers from Rice University and Baylor College of Medicine have developed a method to grow blood vessels in a laboratory. The investigators used biomimetic polyethylene glycol hydrogels embedded with a growth factor called BB (PDGF-BB) to spur angiogenesis, and are now working on a way to guide the formation of vasculature for specific applications.

As its base material, a team of researchers led by West and BCM molecular physiologist Mary Dickinson chose polyethylene glycol (PEG), a nontoxic plastic that’s widely used in medical devices and food. Building on 10 years of research in West’s lab, the scientists modified the PEG to mimic the body’s extracellular matrix — the network of proteins and polysaccharides that make up a substantial portion of most tissues.
West, Dickinson, Rice graduate student Jennifer Saik, Rice undergraduate Emily Watkins and Rice-BCM graduate student Daniel Gould combined the modified PEG with two kinds of cells — both of which are needed for blood-vessel formation. Using light that locks the PEG polymer strands into a solid gel, they created soft hydrogels that contained living cells and growth factors. After that, they filmed the hydrogels for 72 hours. By tagging each type of cell with a different colored fluorescent marker, the team was able to watch as the cells gradually formed capillaries throughout the soft, plastic gel.
To test these new vascular networks, the team implanted the hydrogels into the corneas of mice, where no natural vasculature exists. After injecting a dye into the mice’s bloodstream, the researchers confirmed normal blood flow in the newly grown capillaries.
Another key advance, published by West and graduate student Joseph Hoffmann in November, involved the creation of a new technique called “two-photon lithography,” an ultrasensitive way of using light to create intricate three-dimensional patterns within the soft PEG hydrogels. West said the patterning technique allows the engineers to exert a fine level of control over where cells move and grow. In follow-up experiments, also in collaboration with the Dickinson lab at BCM, West and her team plan to use the technique to grow blood vessels in predetermined patterns.

Time-lapse image showing how two types of cells (tagged red and green) organize themselves into a functioning capillary networks within 72 hours:

Researchers from University of California, Berkeley, University of Minnesota, and Oxford University have developed new technology to speed up how fast neuro fMRI functions. In a study published in PLoS ONE, the researchers were able to achieve large reductions in echo planar imaging (EPI) of whole brain scan time at 3 and 7 Tesla even though the sampling rate was increased 6-fold and the peak functional sensitivity was improved by 60%:

Using echo planar imaging (EPI), fMRI vividly distinguishes oxygenated blood funneling into working areas of the brain from deoxygenated blood in less active areas.
With EPI, a single pulse of radio waves is used to excite the hydrogen atoms, but the magnetic fields are rapidly reversed several times to elicit about 50 to 100 echoes before the atoms settle down. The multiple echoes provide a high-resolution picture of the brain.
In 2002, Feinberg [David Feinberg, physicist and adjunct professor at UC Berkeley and president of the company Advanced MRI Technologies] proposed using a sequence of two radio pulses to obtain two times the information in the same amount of time. Dubbed simultaneous image refocusing (SIR) EPI, it has proved useful in fMRI and for 3-D imaging of neuronal axonal fiber tracks, though the improvement in scanning speed is limited because with a train of more than four times as many echoes, the signal decays and the image resolution drops.
Another acceleration improvement, multiband excitation of several slices using multiple coil detection, was proposed in the U.K. at about the same time by David Larkman for spinal imaging. The technique was recently used for fMRI by Steen Moeller and colleagues at the University of Minnesota. This technique, too, had limitations, primarily because the multiple coils are relatively widely spaced and cannot differentiate very closely spaced images.
In collaboration with Essa Yacoub, senior author on the paper, and Kamil Ugurbil, director of the University of Minnesota’s Center for Magnetic Resonance Research and co-leader of the Human Connectome Project, Feinberg combined these techniques to get significantly greater acceleration than either technique alone while maintaining the same image resolution.
“With the two methods multiplexed, 10, 12 or 16 images the product of their two acceleration factors were read out in one echo train instead of one image,” Feinberg said.

Abstract in PLoS ONE: Multiplexed Echo Planar Imaging for Sub-Second Whole Brain FMRI and Fast Diffusion Imaging
UC Berkeley press statement: Advance makes MRI scans more than seven times faster…