Page 76 - IJB-9-6

International Journal of Bioprinting 3D Aerosol Jet® printing for microstructuring

a AgNPs-based ink b PEDOT:PSS-based ink c Plastic (control)

10 µm 10 µm 10 µm

Figure 7. Fluorescence microscopy images of HFs at day 5 on (a) drop-casted AgNPs-based ink, (b) AJ® printed PEDOT:PSS-based ink, and (c) plastic as
positive control (phalloidin in green, nuclei in blue).

Col Col-HAp Positive control
D1

D7

Figure 8. Live-dead assay of MC3T3 cells seeded onto AJ®-printed collagen-based thin films and positive control at days 1 and 7.
Col-HAp, reaching over confluent cellular layers already which the printed ink becomes too wet (2D printing).
after 7 days. Moreover, this selection must consider a trade-off between
printability and potential biocompatibility needs, avoiding
4. Discussion the use of toxic compounds.
This paper covers the fabrication of 3D microstructures Among the three inks, the 3D-LBL AgNPs-based ink
by means of the AJ®P technology, with focus on the effects demonstrated the best ability to print reproducible 3D
of inks composition and print strategies. Table 3 gives a microstructures (pillars) at the highest ARs and resolutions.
general overview of the results obtained in each scenario. This is caused by its high loading particle, which can be
Three functional inks among AgNPs-, PEDOT:PSS-, and fine-tuned (through dilution) for 2D and 3D printing. In
collagen-based solutions were investigated according the case of 3D printing with the nondiluted solution, the
to different print strategies, that is, 3D CJD, LBL, and solid particle content (~ 50 wt.%) is too high compared
PW printing of structures with at least an AR = 1 and in to the cosolvent concentration (≤ 20 v/v%), leading to a
a fast printing time (≤ 10 min). For all cases, the typical faster evaporation rate in the transport and in-flight jet,
conditions for a satisfactory AJ®P deposition are defined eventually causing the deposition of rough, dendritic-like
as: (i) stable aerosol generation, (ii) optimal evaporation structures. Instead, the dilution allowed the printing of a
rate of the in-flight jet, and (iii) adequate ink-substrate wetter aerosol, reducing the ink drying effect. AgNPs-based
interaction. Thus, the selection of the (co-)solvents system 3D microstructures can be applied in the PE fabrication
plays a fundamental role, which must balance high and of highly conductive, cost-effective, and customizable 3D
low volatile solvents in order not to exceed a certain passive and active elements for energy harvesting devices,
concentration margin (different from case to case), beyond batteries, (optoelectronic) sensors, and so on. However,

Volume 9 Issue 6 (2023) 68 https://doi.org/10.36922/ijb.0257