Microscopic technology has received much attention in the past few years, especially as nanotechnology has entered public consciousness. But vision at the nanotech level is generally limited to electron microscopes operating in a high vacuum, and, for the most part, nanotechnology is experimental and speculative. There are few actual working devices.
In contrast, microtechnology describes larger devices, from one micron (a millionth of a meter) up to those visible to the naked eye, and there are many electrical, mechanical, and analytic devices already in production. These include electronic devices with computer chips, complex analog circuitry, microlasers, flat displays, and the charge-coupled-device (CCD) arrays found in both video and still cameras. The same methods used so successfully in electronics have been adapted for manufacturing microelectromechanical system (MEMS) devices. MEMS products include sensors to measure force, acceleration, pressure, and temperature, and movable micromirrors for switching light signals.
Microtechnology benefits enormously from the simple fact that every step in the fabrication and assembly process can be guided by ordinary vision. At the most, one needs only a common light microscope.
An emerging method of microtechnology production uses modified ink-jet computer printers. The jets deposit liquids containing polymers or powders of solid materials such as metals and ceramics. The drops form a layer that solidifies by evaporation of the solvent, by chemical reaction, or by laser-beam heating. Complex three-dimensional shapes are built up layer by layer to form a completed array of parts that may be further hardened by heating.
Arrays of hollow probes can assemble devices with multiple parts, adding each part simultaneously to an array of partially assembled devices. The probes can pick the parts up by applying a slight vacuum, then deposit them on the growing devices with positive air pressure. Probes equipped with MEMS micro-grippers are another possibility for such pick-and-place assembly of microdevices.
Microtechnology will move forward like standard technology, primarily by small steps that improve existing products in cost, reliability, and function. Products will become smaller and more numerous and decrease in cost in the same way microelectronics has.
When Microtechnology And Biology Meet
When reliable devices reach sizes of around 10 microns, they will enter the range of biological design--the "natural" size of typical human cells. Products in this range will effectively merge the biological world with the manufactured world.
Most human cells range in size from 10 microns upward, easily visible in considerable detail by a standard light microscope. Cells, of course, are extremely complex molecular factories. But they can also be viewed much more simply as biological parts that function much like manufactured devices. Thus, sensory cells for light, sound, touch, pressure, heat, and chemicals correspond to sensors constructed for the same physical phenomena. Muscle cells correspond to actuators, networks of nerve cells to microprocessors. Various brick-, shingle-, and fiber-shaped cells correspond to similar mechanical counterparts. Collagen and elastin, the reinforcing and elastic fibers of the extracellular matrix, have manufactured versions. I coin the word biopart to designate microdevices that have functions similar to cells.
Clothes are a prime example of the potential for designing with bioparts. We can create clothes that provide physical protection from cold and harm, and even adjustable physical support. They can monitor the shape, tension, and motion of the body, as well as internal physiological signals. The clothes might contain facilities for communicating with the outside world by sight, sound, touch, and pressure. …