The use of programmed electrical signals to influence biological events has been a widely accepted clinical methodology for neurostimulation. An optimal biocompatible platform for neural activation efficiently transfers electrical signals across the electrode–cell interface and also incorporates large-area neural guidance conduits. Inherently conducting polymers (ICPs) have emerged as frontrunners as soft biocompatible alternatives to traditionally used metal electrodes, which are highly invasive and elicit tissue damage over long-term implantation. However, fabrication techniques for the ICPs suffer a major bottleneck, which limits their usability and medical translation. Herein, we report that these limitations can be overcome using colloidal chemistry to fabricate multimodal conducting polymer nanoparticles. Furthermore, we demonstrate that these polymer nanoparticles can be precisely assembled into large-area linear conduits using surface chemistry. Finally, we validate that this platform can act as guidance conduits for neurostimulation, whereby the presence of electrical current induces remarkable dendritic axonal sprouting of cells.

Since its inception as a simple, low cost alternative to more complicated lithographic techniques such as electron-beam and dip-pen lithography, capillary force lithography (CFL) has developed into a versatile tool to form sub-100 nm patterns. Utilizing the concept of a polymer melt, structures and devices generated by the technique have been used in applications varying from surfaces regulating cell growth to gas sensing. In this review, we discuss various CFL methodologies which have evolved, their application in both biological and non-biological research, and finally a brief outlook in areas of research where CFL is destined to make an enormous impact in the near future.

Birth defects are a common occurrence in the United States and worldwide. Currently, evaluation of potential developmental toxicants (i.e., teratogens) relies heavily on animal-based models which do not always adequately mimic human development. In order to address this, researchers are developing in vitro human-based models which utilize human pluripotent stem cells (hPSCs) to assess the teratogenic potential of chemical substances. The field of human developmental toxicity assays includes a variety of platforms including monolayer, micropattern, embryoid body, and 3D organoid cultures. In this review, we will overview the field of human teratogenic assays, detail the most recent advances, and discuss current limitations and future perspectives.