Stimuli-responsive biomaterials: smart avenue toward 4D bioprinting

3D bioprinting is an advanced technology combining cells and bioactive molecules within a single bioscaffold; however, this scaffold cannot change, modify or grow in response to a dynamic implemented environment. Lately, a new era of smart polymers and hydrogels has emerged, which can add another dimension, e.g., time to 3D bioprinting, to address some of the current approaches' limitations. This concept is indicated as 4D bioprinting. This approach may assist in fabricating tissue-like structures with a configuration and function that mimic the natural tissue. These scaffolds can change and reform as the tissue are transformed with the potential of specific drug or biomolecules released for various biomedical applications, such as biosensing, wound healing, soft robotics, drug delivery, and tissue engineering, though 4D bioprinting is still in its early stages and more works are required to advance it. In this review article, the critical challenge in the field of 4D bioprinting and transformations from 3D bioprinting to 4D phases is reviewed. Also, the mechanistic aspects from the chemistry and material science point of view are discussed too.

Automated summary

3D bioprinting is an advanced technology that combines cells and bioactive molecules within a bioscaffold, but it lacks the ability to change or grow in response to a dynamic environment. The emerging field of 4D bioprinting, utilizing smart polymers and hydrogels, adds the dimension of time to 3D bioprinting, allowing for the fabrication of tissue-like structures that can change and reform as tissues are transformed. This has potential applications in biosensing, wound healing, soft robotics, drug delivery, and tissue engineering, but more research is needed to advance this field.