Non-thermal plasma BioPrinter with nano-scale precision

Summary form only given. Techniques for patterning of biochemical molecules on different, possibly non-planar, surfaces can be applied in tissue engineering to control adhesion of cells and tissue assembly. Most existing methods of biochemical patterning are suitable only for planar surfaces. No suitable method has been demonstrated for patterning of different chemical materials on non-planar substrates such as those incorporating nanofibers, carbon nanotubes, micro-groves, micro-wells and others. In addition, micro- and nano-scale patterning often relies on complex sequences of lithography based processing steps, which are rarely optimal for sustaining most biomaterials. We have developed a novel method of biochemical patterning which allows micro and nano-scale resolution on non-planar substrates. In this method bio molecules are delivered to charged locations on surfaces by plasma charged water droplets with typical diameter of about 30-50 nm prior to deposition on the surface. Charging of water droplets is accomplished using dielectric barrier discharge (DBD) plasma. In the existing experimental process that we have developed, liquid droplets are generated by method of ultrasonic nebulization (atomization). Droplets are then carried by inert gas (argon or helium) through 10 KV 20 KHz plasma discharge where they gain negative charge. We should note that the mentioned high frequency is non acoustic, but exclusively related only to electrode potential in the DBD-discharge system, and is not going to affect bio-materials or cell integrity. Negatively charged droplets are then "pulled" out of plasma region by electric field. Utilizing various intensities of the deposition electric fields we are able to control droplet deposition rate or droplet residence in the system, which in turn allows us to control size of deposited droplets. Employing various patterns of deposition electrodes we deposit droplets on different planar and non-planar substrates. "Step"-patterned e- ectrodes are used in the near future, while we are planning on creating half-circle patterned electrodes - both allow us to form non-planar 3D patterns of bio-chemicals, leading to micro-array assemblies, organ printing (such as microvasculature), and many other applications. Depending on the particular experiment, either droplets with color-coded enzymes are deposited directly onto the substrate or droplets are deposited onto substrate pre-treated with gel to keep enzymes alive. Detailed analysis of the Plasma BioPrinter, including the issues related to droplet charging and transport through the system, was presented and compared to experimental results.