4D Printing: The Dawn of “Smart” Drug Delivery Systems and Biomedical Applications

Abstract

With the approval of first 3D printed drug “spritam” by USFDA, 3D printing is gaining acceptance in healthcare, engineering and other aspects of life. Taking 3D printing towards the next step gives birth to what is referred to as “4D printing”. The full credit behind the unveiling of 4D printing technology in front of the world goes to Massachusetts Institute of Technology (MIT), who revealed “time” in this technology as the fourth dimension. 4D printing is a renovation of 3D printing wherein special materials (referred to as smart materials) are incorporated which change their morphology post printing in response to a stimulus. Depending upon the applicability of this technology, there may be a variety of stimuli, most common among them being pH, water, heat, wind and other forms of energy. The upper hand of 4D printing over 3D printing is that 3D printed structures are generally immobile, rigid and inanimate whereas 4D printed structures are flexible, mobile and able to interact with the surrounding environment based on the stimulus. This capability of 4D printing to transform 3D structures into smart structures in response to various stimuli promises a great potential for biomedical and bioengineering applications. The potential of 4D printing in developing pre-programmed biomaterials that can undergo transformations lays new foundations for enabling smart pharmacology, personalized medicine, and smart drug delivery, all of which can help in combating diseases in a smarter way. Hence, the theme of this paper is about the potential of 4D printing in creating smart drug delivery, smart pharmacology, targeted drug delivery and better patient compliance. The paper highlights the recent advancements of 4D printing in healthcare sector and ways by which 4D printing is doing wonders in creating smart drug delivery and tailored medicine. The major constraints in the approach have also been highlighted.
 Keywords: 4D printing, smart, drug delivery system, patient compliance, biomaterials, tailored medicine

Additive manufacturing of micropatterned functional surfaces: a review

“…Khan et al demonstrated a smart way of fabricating 4D printed microneedles with barbs that curve in response to curing. This backward bending of the barbed structure as shown in figure 8(d) allows for better drug delivery [237]. Similarly, Han et al printed microneedles with reversed barb structures that demonstrated 18 fold increase in the adhesion of microneedles [235].…”

“…(d) Schematic illustration of 4D printing approach to program deformation of horizontally printed barbs into a backward-facing shape. Reproduced with permission from [237]. CC BY-NC 4.0.…”