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Nanoarchitectonics refers to the use of self-assembled atoms/molecules such as carbon to build up unique patterns for special applications. In tissue engineering, cells are the building blocks for tissues, where proper cell-cell interaction can lead to the build up and formation of human tissues. Based on our experience, the technology of nanoarchitectonics can be used to maximize cell-cell interaction by at least three mechanisms. First, the nanomaterials themselves which are the building blocks with the topographical feature in the nanometric scales can affect the cell behavior by direct interaction with cells. Second, the unique self-assembled patterns (such as nanowires) can also serve as templates to influence cells (such as to orient the cells). Third, the optical or electronic properties (such as π-π interaction) can exert an effect on the mitochondrial activity and metabolism of cells. These three mechanisms may combine to modulate the cell-cell interaction and in turn help cells remodel their own extracellular environment to further enhance the cellular harmonization to generate a meaningful tissue. In the following section, we will describe the examples that use nanoarchitectonics as a way of biomimetics and as a strategy for in vitro tissue architectonics.

Fullerenes have unique biocompatibility and photoelectric properties and are candidate materials for biomedical applications. Several cell membrane proteins in nature such as bacteriorhodopsin also have photoelectric properties. Highly expressible bacteriorhodopsin (HEBR) is a novel light-sensitive opsin that has the potential to trigger neural activities through optogenetic modulation. Here, HEBR plasmids are delivered to human fibroblasts and the cells are exposed to C60 fullerene self-assembled 2D nanosheets. Results show that the above approach combined with light stimulation (3 s duration and three times per day) may promote reprogramming and differentiation of human fibroblasts into neural-like cells in 7 d without any neural induction medium. The special photoelectric properties of fullerenes as culture substrates and transfected HEBR on the cell membrane may provide a new optogenetic platform for regulating the location (C60 nanosheet) and time (frequency of light illumination) for human fibroblasts to become neural-like cells, and may be applied to improve neural regeneration in the future.

The biggest contributors to the substrate noise are supply noises, since the power and ground wires are directly connected to the silicon substrate for CMOS digital cells. Clock trees in large digital designs can acquire large power consumption when thousands of flip-flops transitioning through the switching zone. Memories also draw significant instantaneous power when being accessed. In this paper, a measurement of the substrate noise in conjunction with the supply noises analyses were conducted on a real circuit system. The measured substrate noise waveforms were proportional to the power consumptions and substantially correlated with the supply noises for each test condition. As a result, these observations could be useful for modeling substrate noise effects and developing prevention methods.