Bioreactor design-assisted bioprinting of stimuli-responsive materials for tissue engineering and drug delivery applications

Bioreactors are essential tools in tissue engineering and drug delivery research, providing controlled environments for cell growth, tissue development, and optimization of manufacturing parameters. There are various types of bioreactors, including static, dynamic, perfusion, and rotating systems, each offering unique advantages depending on the application. Key design considerations for bioreactors include the size, geometry, components, materials, and operating conditions needed to support the cultured tissue or organ. Stimuli-responsive materials have emerged as essential components in the design of bioreactors and the fabrication of scaffolds for various applications in tissue engineering and drug delivery. These intelligent materials possess the ability to modulate their properties and functionalities in direct response to external stimuli such as temperature, pH, light, electric or magnetic fields, and biochemical signals. This inherent responsiveness affords precise control over the spatiotemporal manipulation of physical and chemical cues, thereby influencing cellular behavior and facilitating controlled release of therapeutic agents. Commonly employed stimuli-responsive polymers encompass thermoresponsive, pH-responsive, light-responsive, and redox-responsive materials.3D printing techniques allow fabrication of complex, customized scaffolds using digital designs and living cell-laden bio-inks. Bioprinting combined with stimuli-responsive materials enables 4D printing of dynamic scaffolds that transform over time when triggered. Ongoing research aims to optimize bioreactor design, develop novel smart biomaterials, achieve multi-material 4D printing, and enhance responsiveness to internal stimuli for advanced tissue engineering and drug delivery applications.