Invenios, Inc.
The bio-fluid printer and our key advisors are closely connected to Invenios, which was
founded by Ray Karam in October of 2002. Invenios’ mission is to bring micromanufacturing to
the third dimension. Arrays of products, process technologies and services from Invenios have
been designed in order to allow for the next generation of integrated nanosystem and
microsystem products and technologies. Invenios is a manufacturer of production equipment and
custom 3D micromachines that help emerging manufacturing companies reduce prototype,
production, and packaging costs for a range of microsystem manufacturing applications.
Our key advisors include Ken Richards, Ray Karam, and George Roussos. Ray Karam is
the president and CEO of Invenios who is an accomplished entrepreneur in the materials and
precision engineering arenas. Ken Richards is vice president and in charge or finance for
Invenios. He has 25 years of experience in the corporate and investment banking. Including
George Roussos, the director of engineering for Invenios, these three advisors have assisted in
supplementing, focusing, and informing our team for this project. Jim Harber, PhD and ChingHua Wang, MD, PhD have also been an incredible source of assistance throughout the process of
completing this project.
Bio-fluid Printer
Invenios’ bio-fluid printer is essentially a high speed, highly accurate device capable of
dispensing small volumes in the pL range. The product is produced as cartridges (figure 1)
approximately the size of a microscope slide. Each cartridge can contain up to 128 print heads.
Each print head is self contained and piezo driven.
Figure 1: Invenios’ bio-fluid printer cartridge
The extremely small size of the printer heads allow the bio-fluid printer to eject droplets
between 30-1000pL. The piezo system that is utilized in the printer heads is what allows for
speeds up to 10,000 droplets per second in a flow through system. By using the print heads along
with another Invenios product, their nanopositioning motion control technology, the bio-fluid
printer is capable of dispensing fluids at resolutions up to 600dpi very accurately.
Figure 2: Diagram of a typical printer head
The technology used in Invenios’ printer heads is very similar to the technology that has
been used in standard inkjet printers since the 1980’s, except Invenios’ printer heads are smaller
and have a primary structure entirely made of glass. Each print head consists of a piezo that is
attached to the side of the printer head along the coverplate. When the piezo is electrically
charged it will cause the piezo to alter its shape, essentially bending away from the cavity,
pulling the coverplate with it. By pulling the coverplate away from the cavity, the charged piezo
creates a small vacuum in the cavity and as a result fluid is drawn into the cavity from the input
at the top of the printer head (figure 2). The fluid is pull mainly from the input and not the nozzle
due to the capillary effect that increases the required amount of force necessary to moving the
fluid in the nozzle tip into the cavity compared to the input. When the piezo is no longer charged,
it will return back to its rest state along with the coverplate that it is attached to. Because there is
now more fluid in the cavity, the piezo put pressure on the fluid within the cavity. The piezo is
charged intermittently very quickly and as a result creates essentially waves within the cavity.
Theses waves result in the ejection of fluid from the print head at varying speeds depending on
the speed that the piezo is being intermittently charged.
One of the key factors that makes Invenios’ bio-fluid printer so unique is that the
cartridges are made entirely of glass. Glass has several unique properties that make it ideal for
bio-fluidics. The benefits include glass’ capability to act as a electrical insulator and its ability to
remain chemically stable. This allows Invenios’ bio-printer to be used with a wide variety of
fluids if necessary for a particular application, such as oil-based, extreme solvent-based, UV
curable, extreme pH level, corrosive, and hot melt fluids. The glass used by Invenios is also ideal
due to its ability to retain structural rigidity even when sustaining high temperatures up to 400ºC.
But more importantly for bio-fluids, the technology used in Invenios’ printers allow for the
ejection of the fluids without needing the fluid to come into contact with anything but glass and
the fluid is also not exposed to any temperature stress during the process. This makes the printer
safe for dispensing various bio-fluids such as serums, proteins, enzymes, vaccines, or even stem
cells. Because of the non-reactive nature of the bio-fluid printer, it is ideal for any type of
application that may need FDA approval.
Direct-Write Laser Patterning Process
Not only is glass an ideal medium for bio-fluidics, but it is also an essential component
that allows Invenios’ direct-write laser patterning process to function in order to create the nano
scale channels in glass for the bio-fluid printer heads.
The term “direct write” refers to “any technique or process capable of depositing,
dispensing, or processing different types of materials over various surfaces following a present
pattern or layout” (Alberto Pique). The laser patterning process takes advantage of very unique
characteristics that are inherent in photo-structurable glass ceramics. When this type of glass is
exposed to UV laser energy density greater than a critical fluence, a photo-chemical reaction
takes place that will create a density of nanocrystals within the criticall-expised volumes (figure
3).
Figure 3: UV exposed photo-structurable glass.
The amount of nanocrystals that forms is directly proportional to the amount of fluence
that is applied to the glass. Sub-micron features within the glass can be created by controlling the
aperture of the UV laser optics and depth of focus. A larger depth of focus can be used in order
to create larger densities of nanocrystrals, resulting in a larger canal formed for the bio-fluid
printer head.
Each critically exposed volume can be extended to form a specific path by utilizing
successive pulses from the laser. The path can be precisely controlled by using a computer
controlled multi-axis positioning system. By using this technique and altering the characteristics
of the laser, complex 3D volumes of nanocrystals can be formed.
By using Invenios’ thermal treatment protocol, the nanocrystals can be grown to form
large crystalline structures. The thermal treatment protocol and the fluence levels that were
applied to the glass will cause the “ceramicized” material to change color. The material will
transition from transparent though yellow, orange, red, brown, and finally black. This
characteristic allows for the creation of embedded masks with sub-micron features.
When the glass is subjected to a mild etchant, the areas of the glass that were critically
exposed by the UV laser will etch faster than the unexposed regions by an etch contrast ratio that
is defined by a non-linear function of the exposure. Etch rate contrasts of 25:1 have been
observed (F.E. Livingston). This suggests that there is a very small range that is undesirable
because it is not critically exposed or unaffected by the laser. As a result, when etching the
critically exposed volume can be removed, but small amounts of non-exposed volumes at the
boundary will be removed as well. Because the amount is so minor, the technique is still capable
of creating the sub-micron features that are required for the bio-fluid printer heads. After the
etching processes a second UV exposure and baking step can take place. This additional step of
thermal treatment and UV exposure is used in order to convert the glass into the full ceramic
state.
Nano Positioning
The bio-fluid printer cartridges are capable of ejecting the droplets with consistent
velocity and direction. The bio-fluid cartridges can also eject droplets as small as 30pL, but these
impressive capabilities would all be useless if there was not a mechanism in place to have the
cartridges accurately positioned over their desired targets. To do this, Invenios implemented
another technology that they have ownership of, their nanopositioning motion control
technology. The combination of the small nozzle distances between the printer heads and
Invenios’ nanopositioning motion control technology allows the bio-fluid printer to dispense
fluids at resolutions up to 600dpi.
The precision linear and rotary stages that Invenios’ owns is a scalable precision ballscrew stage that is capable of the precise nanopositioning that is required for the accurate
dispensing of bio-fluids with their bio-fluid printer. Invenios’ has a nano series of the precision
linear and rotary stages that allows them to achieve sub-micron out-of-plane motion at intervals
as small as 0.05um over 10mm. It is also capable of precision linear resolution and repeatability
of 1nm using a dual-loop feedback system.
Alberto Pique, Douglas B. Chrisey, “Direct-Write Technologies for Rapid Prototyping
Applications: Sensors, Electronics and Integrated Power Sources,” Academic Press, 2002, pg.
XIX
F. E. Livingston and H. Helvajian, " True 3D Volumetric Patterning of Photostructurable Glass
using UV Laser Irradiation and Variable Exposure Processing: Fabrication of Meso-scale
Devices," SPIE Proc. Vol. 4830 (2003) pg. 189-195.
Invenios, Inc, “Micro Applications, Nano Positioning, and Company,” www.invenios.com