Biomedical Engineering Reference
In-Depth Information
The parallels in solid-state physics and engineering to biochemistry are
enlightening. For instance, models for electron transport through respi-
rasomes are analogous to the energetic transport of electrons in solid-state
physics. The semiconductor model involves electrons in the valence band,
excited to the conduction band, and essentially hopping along the crystal
matrix through successive donor-acceptor energetics. In the semiconductor,
“pumping” or increasing the electron energy across a band gap is necessary
for electron transport, while in the biochemical model the proton-motive
force across a membrane supplies the “pump.”
Each mechanism exhibits its own electron transport stimuli, for instance,
increased nano-ordering of water in a hydrogen-bonded contiguous macro-
molecule serving to “epigenetically” influence the transport of ions across a
cell membrane or to influence protein folding. What are the light-activated
switching mechanisms in proteins? Are there aspects of epigenetic program-
ming that can be “switched” with light? If we “express” such a protein in a
cell, can we then control aspects of the protein's behavior with light?
Consider the analogy of the progression of signal processing using com-
binations of digital logic gates and application-specific integrated circuits
to optical signal processing using operator transforms, optical index, and
nonlinear bistable functions through acousto- and electro-optic effects to
perform optical computing; to Dennis Bray's “Wetware” biologic cell logic
[1]; and to the astounding insights of Nick Lane in the last two chapters
of his recent “Life Ascending—the Ten Great Inventions of Evolution” [2],
where Lane characterizes the evolutionary development of consciousness
and death (through the mitochondria), providing the basis for the biological
logic and how best to modify and control that inherent logic (see Chapter 7,
Section 7.5.5).
We are on the cusp of an epoch, where it is now possible to design light-
activated genetic functionality, to actually regulate and program biological
functionality. What if, for instance, we identify and isolate the biological
“control mechanism” for the switching on and off of limb regeneration in
the salamander, or, with the biophotonic emission associated with cancer
cell replication, and analogous to the destruction of the cavity resonance in a
laser, we reverse the biological resonance and switch or epigenetically repro-
gram the cellular logic?
Scaffolds are three-dimensional nanostructures fabricated using laser
lithography. Perhaps, complex protein structures could be assembled onto
these lattices in a preferred manner, such that introduction of the lattice
frames might “seed” the correct protein configuration. This inspires the con-
cept of biocompatible nanostructures for “biologically inspired” computing
and signal processing, for example, biosensors in the military, or for recreat-
ing two-way neural processes and repairs.
By spatially recruiting metabolic enzymes, protein scaffolds help regu-
late synthetic metabolic pathways by balancing proton/electron flux. This
represents a synthesis methodology with advantages over more standard
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