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International Journal of Bioprinting 3D printing and 3D-printed electronics in smart drug delivery devices

Figure 1. (a) The use of a stereolithography 3D printer for fabrication of the microfluidic microneedle and the 3D model. (b) Printed microneedle device
with three separate microfluidic inlets which leads to a mixing chamber and subsequently to the hollow microneedles. (c) Zoomed-in image of the three
inlets converge junction. (d) Zoomed-in image of the hollow microneedles. (Reprinted with permission from . Copyright (2019) AIP Publishing.)
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electrolysis from the pump will cause a membrane to swell, the device, preventing the device from leaving the stomach.
pushing the drug from the reservoir out through a nozzle in The 3D-printed shell of the device is also designed with
the pill to be released. By controlling the current supplied to the compartments which allows for the addition of electronics,
pump, the deflection of the membrane changes, controlling sensors, and drug reservoirs, allowing for long-term
the amount of drugs released. 3D printing allowed for the pill monitoring, wireless feedback, and drug release. After a
capsule to be designed and fabricated with compartments period of time, the arms detach from the device, allowing
to contain all the necessary parts, such as the pump and for the device and the arms to pass through the digestive
the electronic controlling components. In another example, system. Casings for smart drug delivery devices using other
3D printing was used to fabricate a capsule for a smart pill methods of drug delivery have also been fabricated using 3D
which contains multiple near-infrared (NIR) LEDs . The printing. In one such example, vat-based 3D printing was
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NIR LEDs allow for the tracking of the location of the pill as it used to fabricate microreservoirs with customizable shape
passes through the digestive system. The capsule was designed and volume to operate with a 3D-printed micropump for on-
with slots into it for placing the LEDs. The slots also contained demand drug release (Figure 2a) . The entire device was
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opening to allow for electrical connections. By tracking the housed in a 3D-printed biocompatible casing (Figure 2b).
location of the pill, it would allow for the release of the drugs The scalability, customizable design, and biocompatibility of
to be triggered at specific areas within the digestive system. the printed device allows for the device to be implanted into
This would allow for targeted drug delivery to specific areas different parts of the body for long-term drug release . In
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or for drugs to be released in certain area for increased drug another example, 3D printing was used to fabricate a flexible
efficacy. bandage used for drug delivery for wound management .
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The patch was designed to contain the wireless electronic
The use of 3D printing for drug delivery shells allows control component, the flexible heater and the drug reservoir.
for the fabrication of specially designed shells. For example, The flexibility of the patch allows for the bandage to better
multi-material 3D printing was used to fabricate a gastric- conform to the wound area, providing better interface and
resident electronic device . The device was uniquely conformance to the wound.
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designed with different materials forming different parts
to allow for the device to be delivered orally and to reside 2.4. Advantages of 3D printing in the fabrication of
in the stomach for long periods of time. The joints of the smart drug delivery devices
arms of the device were printed with a flexible material, One of the advantages of using 3D printing for the
allowing for the stiff arms to be folded in a more compact fabrication of smart drug delivery devices with electronics
shape for oral delivery. When the device reaches the is its ability to fabricate design, which is difficult or
stomach, the arms unfold. This increases the overall size of impossible to achieve with traditional fabrication methods.

Volume 9 Issue 4 (2023) 148 https://doi.org/10.18063/ijb.725