Inkjet dispensing technologies: recent advances for novel drug discovery

Abstract

Inkjet-dispensing printing is a promising additive manufacturing method for pharmaceutical applications such as drug discovery. The unique advantages of this technology, including low cost, programmability, high resolution, high throughput, high speed, and biocompatibility, may reduce the financial resources needed to discover new drug candidates. Sophisticated and miniaturized assays have been developed to accomplish drug discovery and drug screening using modern inkjet dispensing printers. Areas covered: This paper reviews recent advancements in the field of inkjet printer technology for drug discovery. Various types of inkjet printers and their recent use for the drug discovery are summarized; physical and biological limitations of this technology are also examined. Furthermore, typical inks used in the inkjet printing technology are introduced. Expert opinion: Inkjet bioprinting technology is a promising tool for many biological and pharmaceutical applications. Several bottlenecks associated with this technology need to be addressed before commercialization. For example, sophisticated inks need to be synthesized to meet both biological and engineering restrictions. Further progress of parallel technologies will enhance the performance and functionality of the printers. It is also worth emphasizing that inkjet printing technologies must meet the requirement of regulatory agencies (e.g. the US Food & Drug Administration) for commercialization by the pharmaceutical industry.

Keywords: Inkjet dispensing technology; drug discovery; drug screening; ink; inkjet printer.

Figure 1.

Classification of inkjet printing technologies. Reproduced from [16] with permission of IS&T: The Society for Imaging Science and Technology; sole copyright owners of The Journal of Imaging Science and Technology..

Figure 2.

Schematic of various inkjet printing process (reprinted from [22] with permission of Elsevier).

Figure 3.

Droplet formation sequence for PEGDA ink (reprinted from [23] with permission of Elsevier).

Figure 4.

The working principles of various types of bioprinters, including continuous (A1), thermal (A2), piezoelectric (A3), acoustic (A4), and electrohydrodynamic(A5) inkjet printing technologies (reprinted from [33] with permission of Elsevier).

Figure 5.

Drop shape of ink on various substrates: (a) copy paper, (b) transparency film, and (c) orodispersible film (reprinted from [37] with permission).

Figure 6.

Schematic showing the difference of contact angles on uncoated (A) and coated (B) hydrophobic nonporous films (reprinted from [45] with permission of Elsevier).

Figure 7.

Sequence images of the formed droplet at the nozzle tip with frequencies of 5 and 10 Hz. (Reprinted from [51] with permission of Elsevier).

Figure 8.

Schematic showing the forces associated with the liquid cone (Reprinted from [52] with permission).

Figure 9.

Optical microscope and polarized images of (triisopropylsilylethynyl) pentacene droplets in various solvents: a) chlorobenzene b) hexane, c) o-dichlorobenzene, and d) dodecane (reprinted from [88] with permission of John Wiley and Sons).

Figure 10.

3D QR inkjet printing schematic on capsules and identifying by smartphones. a) Printing 3D QR code on capsule by an inkjet printer. b) Identifying the printed code on capsuled by smart phones. c) The capsule before printing QR code ([17]-Reproduced by permission of The Royal Society of Chemistry)