Adapting an Epson R280 printer to print protein solutions Introduction 1 The instructions below describe all steps for adapting the Epson R280 printer to print protein solutions. A similar procedure was described by Cohen, et al. (PLoS One, 2009), but the instructions here provide some simplifications and added detail. The approach requires minimal hardware modification, and the methods can likely be applied to other printer models. A list of journal articles that use inkjet printers is given at the end these articles use a wide range of printers from expensive commercial systems to low cost home office printers. Note that this Epson printer pairs a permanent piezoelectric print head with replaceable ink cartridges. The instructions below do not modify the print head in any way. We hope that these instructions are useful to the community. We are also eager to get feedback, corrections, or improvements on these instructions, as well as to disseminate instructions for adapting other printers. Cautions: If any cables are disconnected, the printer will not work again; there is no need to remove cables for the procedure below. Removing the printer case could pose an electrocution hazard; there is no need to remove the printer case for the procedure below. Fluids can ruin the printer or create an electrocution hazard; do not spill fluids on the printer. Do not attempt to print hazardous materials such as flammable or infectious fluids. Cautions above are not intended to be a complete list of hazards; use your own judgment to avoid unsafe actions. This procedure has not been endorsed by the manufacturer in any way, and the authors take no responsibility for any damage to equipment or personnel that may occur because of properly or improperly following of the instructions below. 1 This work was performed by James Wong under the supervision of Barry Lutz and Paul Yager at UW Department of Bioengineering from June 2009 to August 2011 under support of an NIH Challenge Grant (1RC1EB010593, Yager PI).
Materials Printer with CD printing capability (here, the Epson R280) CD Printing Software (often included with printer, but can also use programs such as Photoshop, GIMP) Third party refillable ink cartridges with auto reset chips (e.g., http://www.inkproducts.com/ink-store441/) Power cutting tool (e.g., Dremel, used to cut holes in the refillable ink cartridges) Aluminum foil (to trick the printer to think that a CD is present) 200 microliter pipette tips for creating the fluid reservoir (e.g., FisherBrand SureOne P200 Pipette tips) Pipette or air pressure source 5-10 ml syringes Water and ethanol for flushing the print head Modified ink solutions (consisting of: protein to be printed (with solvent), surfactant (Triton X-100)) Medium upon which to print (e.g., nitrocellulose membrane strips) General information Fragile porous materials (e.g., nitrocellulose) that can be damaged by bending through a tight radius were printed using the CD printing tray, which avoids passing the material through the paper feed. This printer has a photosensor to verify that a CD is in place (which was designed for recognizing the reflective back surface of CDs). Here, the sensor was overridden by taping aluminum foil in the CD tray. A grid pattern can be printed onto the foil for alignment of materials. Even new printers may have ink previously loaded into the print head this ink must be thoroughly removed prior to use with protein solutions. A flushing procedure is described for this case. Printer cartridges include electronic chips that must be present for the printer to operate. Refillable cartridges from third-party vendors were used to trick the printer into believing that a full cartridge was present, and were trimmed to allow access to the printer head port. Color values used to select individual ink cartridges were found in flush files for the printer. The flush files may be specific to each printer or family of printers. These are provided below for the Epson R280. The internal volume of each print head channel is ~30-50 microliters. Additional capacity can be provided by connecting a reservoir to a print head port (trimmed pipette tips, tubing). When the reservoir is depleted, 30-50 microliters will remain (internal volume of printhead); this fluid can
be printed but care must be taken to ensure that the print head does not run out of fluid (which would lead to devices not receiving printed fluid; there is no out of ink message that works for this setup). Summary of one-time modifications to a new printer (details explained in sections that follow): Add foil reflector to the CD tray Flush any prior ink from the print head (even for a new printer in some cases) Add a reservoir to the print head port to hold solutions to be printed Create a cutout in a refillable ink cartridge to allow it to fit around the reservoir Summary of operations performed for each printing run (details explained below in sections that follow): Create a pattern to print Add a clean reservoir to the print head port Prime the print head channels Print the desired pattern Flush and dry the print head after use ONE-TIME MODIFICATIONS TO THE PRINTER Clean ink from the system Materials: 5-10 ml syringe, short length of clean tubing (~2 mm ID, flexible tubing is good, able to fit over the syringe tip and the ink port, which are of similar size), ~10 ml of DI water and ~10 ml of ethanol (we used lab grade ethanol) for each ink channel to be flushed, absorbent material (paper towel or cellulose wicking paper). Turn on the printer Press the ink load button until the carriage is positioned in the load station Remove power to the printer and remove all cartridges Fill a syringe with 5-10 ml of water flushing fluid Slide a paper towel underneath the carriage between cleaning each nozzle Flush each nozzle with water and ethanol, taking care to move the absorbent material so that it does not overflow Fill a syringe with air and flush the nozzle to remove most of the liquid Turn on the printer, the head will return to the base station The print head is clean do not put original ink cartridges back in Modify printer hardware Materials: aluminum foil, razor blade, tape, reservior (pipette tip or tube), pipette or air pressure source, refillable ink cartridge.
Attach aluminum foil to the CD tray with tape; foil can be cut to the shape of the CD with a razor blade or scissors. Create a reservoir to hold the printing solution. For very small reagent volumes, trim the narrow end of a pipette tip (P200) such that the tip fits snugly onto printer head ports. Alternative methods are noted below**. In a refillable ink cartridge, make a cutout large enough to clear the pipette tip reservoir. Modified ink Pipette **Alternative methods for creating the reagent source. The reservoir should hold the desired volume of source fluid and have some means to push fluid through the print head for the initial priming step (to displace air and fill the print head with fluid). The main method above uses a trimmed pipette tip and a pipette to push fluid. An alternative is to use a tube of any length or a tube connected to a disposable syringe to hold larger volumes of the source reagent. In this case, a pressurize air line can be used to push the fluid into the print head. Pressure can also be used with the pipette tip method. CREATING THE DESIGN Materials: CD printing software that comes with the printer, or third-party software with a plugin for CD printing (e.g., Photoshop, PhotoImpressions, GIMP).
Select the RGB value corresponding to the channel to be printed R G B Black 0 0 0 Yellow 255 255 0 Cyan 0 0 255 Magenta 255 0 255 Light Cyan - - - Light Magenta - - - Draw or type the objects to be printed with the selected channel; save file. PRINTING FLUIDS Materials: 5-10 ml disposable syringe, short length of clean tubing (~2 mm ID, flexible is good, able to fit over the syringe tip and the ink port, of similar size), ~10 ml of DI water and ~10 ml of ethanol for each channel to be flushed, absorbent material (paper towel or cellulose wicking paper). As a first step, the print head should be flushed with fluid to ensure that it is filled properly. When the reagent to be printed is precious, the initial filling step can be performed using a fluid containing the components of the solution to be printed but with the precious reagent absent (the matrix fluid). For example, when printing an antibody in buffer containing Triton X-100, the matrix fluid was buffer containing Triton X-100. Preparation of fluids: For each solution to be printed, prepare 5-10 ml of the matrix fluid, and prepare at least 50 microliters of the printing fluid containing the reagent.
Flush the printhead Turn on the printer Press the ink load button until the carriage is positioned in the load station Remove power to the printer and remove all cartridges Optional: flush the print head with matrix fluid o Connect a syringe with 5-10 ml of flushing fluid to the print head port via a tube o Slide a paper towel underneath the carriage between cleaning each nozzle o Flush each nozzle with the flushing fluid, taking care to move the absorbent material so that it does not overflow o Refill the syringe with air and flush the nozzle to remove most of the liquid Load the printing solution Install a clean reservior (pipette tip or alternative) Add the desired volume of printing solution into cut pipette tips Place a clean absorbent material underneath the print head and flush fluid until the absorbent material is slightly wet (pressure applied by a pipette or air pressure source) The channel is ready to print; repeat for other channels Place the material and print Place substrate material onto aluminum foil and secure with tape Plug the printer into power source and turn on Print the image file Clean the printhead Press the ink load button until the carriage is positioned in the load station Remove power to the printer and remove all cartridges and fluid sources Flush and dry the print head o Connect a syringe with 5-10 ml of rinsing fluid (DI water) to the print head port o Slide a paper towel underneath the carriage between cleaning each nozzle o Flush each nozzle with the rinsing fluid, taking care to move the absorbent material so that it does not overflow o Refill the syringe with air and flush the nozzle to remove most of the liquid References Below is a list of journal articles that describe or use inkjet printing (range from expensive to low-cost printers). 1. K. Abe, K. Suzuki and D. Citterio, Analytical Chemistry, 2008, 80, 6928-6934. 2. I. Barbulovic-Nad, M. Lucente, Y. Sun, M. J. Zhang, A. R. Wheeler and M. Bussmann, Critical Reviews in Biotechnology, 2006, 26, 237-259. 3. P. Calvert, Chemistry of Materials, 2001, 13, 3299-3305.
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