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International Journal of Bioprinting Amphiphobic encap. for transient devices

Figure 4. Effect of the number of amphiphobic stacks on encapsulation characteristics. (A) Varying encapsulation layers are distinguished by the number
of stacking, ranging from 1 (3P/500) to 10 (3P/[50*10] amphiphobic ). (B) Measured resistance of Mg resistors (i.e., 300 nm Mg on top of 20 nm Cr) based on the
number of stacking layers. (C) Linear regression results of measured resistance based on the number of stacking layers. (D and E) Mechanical properties
of amphiphobic layers: stress–strain curves (D) and comparison of samples, in terms of strain, Young’s modulus, and toughness, against SP/500 (dashed
line) (E).

exhibiting a linear relationship (y = 10.61x + 38.58; R lifetime, and this parameter validates the waterproofing
2
= 0.98091). Regarding the mechanical characteristics of functionality of the device. The samples (SP/500,
the amphiphobic layer, there were minimal differences in 3P/500, and 3P/[50*10] amphiphobic ) reported functional
strain, modulus, and toughness among samples, despite lifetimes of 6, 12, and 30 h, respectively (Figure 5D).
their disparate waterproofing properties (Figure 4D This trend is similar to that observed in the EDR test. In
and E). All amphiphobic samples displayed enhanced the actual implant device, metals (Mo, Fe, and W) with
mechanical properties compared to SP/500 (dashed line in slower melting rates and thicker than 300 nm may be used
Figure 4E) with minimal standard deviations. Average to extend the operational lifetime. 30
strain and toughness increased by 111.41% and 162.04%,
while modulus decreased by 41.90%. The improved 4. Conclusion
properties of amphiphobic PBTPA, including both In this study, we evaluated and compared the properties of
waterproofing and mechanical characteristics, would PBTPA, a photocurable and biodegradable encapsulation
make it suitable for real-world, clinical applications. polymer, in screen-printed and 3D-printed encapsulation
To verify the practical application of our proposed layers, in terms of their waterproofing, lifetime, elongation,
3D-printed polyanhydride membrane, additional device- Young’s modulus, and toughness. The results indicated
level demonstration was performed. Figure 5A features that 3D printing can maintain consistent crosslinking
the device, which includes an LED and a bioresorbable Mg while reducing the attenuation effects that may occur
tracer. The completed device includes an antenna, enabling during screen-printing. A comparison of the elongation,
the LED to be powered on from an external wireless power Young’s modulus, and toughness from the stress–
source (Figure 5B). Additionally, the device is embedded strain curve demonstrated the successful fabrication
in agarose (containing PBS), and the LED turns off as the of 3D-printed encapsulation layers that are relatively
resistance increases due to the dissolution of Mg (Figure 5C). soft and stretchable, with remarkable waterproofing
The time when the LED turns off is defined as the functional properties. The newly introduced concept of amphiphobic

Volume 10 Issue 5 (2024) 315 doi: 10.36922/ijb.3871