Printable nanocomposites of polymers and silver nanoparticles for antibacterial devices produced by DoD technology.

Silver nanoparticles (Ag-NPs) are known for their efficient bactericidal activity and are widely used in industry. This study aims to produce printable antibacterial devices by drop-on-demand (DoD) inkjet technology, using Ag-NPs as the active part in complex printable fluids. The synthesis of this active part is described using two methods to obtain monodisperse NPs: chemical and microwave irradiation. The synthesized NPs were characterized by UV-VIS, STEM, TEM, DLS and XRD. Two printable fluids were produced based: one with Ag-NPs and a second one, a polymeric nanocomposite, using silver nanoparticles and polyvinyl butyral (Ag-NPs/PVB). Cellulose acetate was used as a flexible substrate. The ecotoxicity analysis of fluids and substrate was performed with Artemia franciscana nauplii. Optimized electric pulse waveforms for drop formation of the functional fluids were obtained for the piezoelectric-based DoD printing. Activity of printed antibacterial devices was evaluated using the Kirby-Bauer method with Staphylococcus aureus and Escherichia coli. The results show that the printed device with Ag-NP fluids evidenced a bacterial inhibition. An important advantage in using the DoD process is the possibility of printing, layer by layer or side by side, more than one active principle, allowing an interleaved or simultaneous release of silver NP and other molecules of interest as for example with a second functional fluid to ensure effectiveness of Ag activity.

Inkjet Printing of Proteins: an Experimental Approach.

Peptides and proteins represent a promissory group of molecules used by the pharmaceutical industry for drug therapy with great potential for development. However, the administration of these molecules presents a series of difficulties, making necessary the exploration of new alternatives like the buccal route of administration to improve drug therapy compliance. Although drop-on demand printers have been explored for small molecule drugs with promising results, the development of delivery systems for peptides and proteins through inkjet printing has seen little development. Therefore, the aim of this study was to assess the feasibility of using a thermal inkjet printing system for dispensing lysozyme and ribonuclease-A as model proteins. To address the absorption limitations of a potential buccal use, a permeation enhancer (sodium deoxycholate) was also studied in formulations. We found that a conventional printer successfully printed both proteins, exhibiting very high printing efficiency. Furthermore, the protein structure was not affected and minor effects were observed in the enzymatic activity after the printing process. In conclusion, we provide evidence for the usage of an inexpensive, easy to use, reliable, and reproducible thermal inkjet printing system to dispense proteins solutions for potential buccal application. Our research significantly contributes to present an alternative for manufacturing biologics delivery systems, with emphasis in buccal applications. Next steps of developments will be aimed at the use of new materials for printing, controlled release, and protection strategies for proteins and peptides.