Researchers grow cyborg tissue that can sense its environment...
Oh goodie...
I'ts like watching one of those horror movies in slow motion, you know where the man walks down the slatted staircase into the dark basement...and then the 'cyborg tissue that can sense its environment' grabs his foot and pulls him through screaming... yip just like that... oh goodie.
An ongoing problem in the field of tissue engineering has been in getting biomaterials to monitor or interact with changes around them. Normal human tissue can sense chemical and electrical changes, such as pH, chemistry, oxygen, and other factors, and then trigger an autonomic response. Materials scientists have struggled to find a way to mimic these feedback loops and maintain control at the cellular and tissue level.
The research team, which was led by Charles M. Lieber, the Mark Hyman Jr. Professor of Chemistry at Harvard, and Daniel Kohane, a Harvard Medical School professor in the Department of Anesthesia at Children's Hospital Boston, say that the technology will allow them to work at the same scale as the unit of a biological system.
By using the human autonomic nervous system as a model, the researchers built meshed networks of nanoscale silicon wires — a process similar to how microchips are etched. Starting with a two-dimensional sheet, the researchers laid out a mesh of organic polymer around tiny wires — wires that would later serve as the critical sensing elements. Then, nanoscale electrodes were built within the mesh, thus allowing the nanowire transistors to measure the activity of the cells. After this was done, the substrate melted away, leaving a netlike material that could be folded or rolled into any number of three-dimensional shapes.
As hoped, the material was spongy and porous enough to be seeded with heart and nerve cells — and to allow those cells to grow in 3-D cultures. This was the first time that the researchers were able to work outside of 2-D limitations.
Moreover, the researchers were also able to detect electrical signals generated by cells deep within the tissue, and to measure changes in those signals facilitated by cardio- or neuro-stimulating drugs. And remarkably, they were also able to construct bioengineered blood vessels which were in turn used to measure pH changes — the kind of responses that would typically be seen when tissue responds to inflammation or ischemia.
The researchers suspect that the pharmaceutical industry will benefit the most from this technology, allowing them to study how drugs work in 3-D tissues. But looking ahead to the future, it's clear that this breakthrough will hold profound implications for human functioning and the body's ability to detect and react to any number of changes in its environment.
Macroporous nanowire nanoelectronic scaffolds for synthetic tissues
The development of three-dimensional (3D) synthetic biomaterials as structural and bioactive scaffolds is central to fields ranging from cellular biophysics to regenerative medicine. As of yet, these scaffolds cannot electrically probe the physicochemical and biological microenvironments throughout their 3D and macroporous interior, although this capability could have a marked impact in both electronics and biomaterials. Here, we address this challenge using macroporous, flexible and free-standing nanowire nanoelectronic scaffolds (nanoES), and their hybrids with synthetic or natural biomaterials. 3D macroporous nanoES mimic the structure of natural tissue scaffolds, and they were formed by self-organization of coplanar reticular networks with built-in strain and by manipulation of 2D mesh matrices. NanoES exhibited robust electronic properties and have been used alone or combined with other biomaterials as biocompatible extracellular scaffolds for 3D culture of neurons, cardiomyocytes and smooth muscle cells. Furthermore, we show the integrated sensory capability of the nanoES by real-time monitoring of the local electrical activity within 3D nanoES/cardiomyocyte constructs, the response of 3D-nanoES-based neural and cardiac tissue models to drugs, and distinct pH changes inside and outside tubular vascular smooth muscle constructs.
Conventional bulk electronics are distinct from biological systems in composition, structural hierarchy, mechanics and function. Their electrical coupling at the tissue/organ level is usually limited to the tissue surface
a, Device fabrication schematics. (I) Reticular nanowire FET devices. (II) Mesh nanowire FET devices. Light blue:silicon oxide substrates; blue: nickel sacrificial layers; green: nanoES; yellow dots: individual nanowire FETs.b, 3D
a,b, Basic design and structural subunit for simulation. a, Top-down view of the entire subunit. Blue ribbons are stressed metal lines with SU-8 passivation. Red lines are single SU-8 ribbons without residual stress. b, Cross-sectional views
a, Confocal fluorescence micrograph of a hybrid reticular nanoES/collagen matrix. Green (fluorescein isothiocyanate): collagen type-I; orange (rhodamine 6G): epoxy ribbons. The white arrow marks the position of the nanowire. Scale bar, 10 μm
a,b, 3D reconstructed confocal images of rat hippocampal neurons after a two-week culture in Matrigel on reticular nanoES. Red (Alexa Fluor 546): neuronal β-tubulin; yellow (rhodamine 6G): epoxy ribbons. The metal interconnects are false
a, Schematic of the synthesis of smooth muscle nanoES. The upper panels are side views, and the lower ones are either top views (I and II) or a zoom-in view (III). Grey: mesh nanoES; blue fibres: collagenous matrix secreted by HASMCs; yellow
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