Purification of Tubulin from Porcine Brain and its Fluorescence Dye Modification.

Filamentous microtubules, polymers of the heterodimeric protein tubulins play one of the major roles in the emergent nano-biotechnological devices. To develop the feature of those devices, it is important to understand the function of microtubule in in vitro, hence, the availability of purified αß-tubulin is required. Additionally, fluorescently labeled tubulin has become a powerful approach for extensively studying the dynamics of these components. In this chapter, the process of purifying the heterodimeric αß-tubulin from porcine brain will be described, as well as the process of labeling of the purified tubulin with fluorescence dye.

Functionalization of Tubulin: Approaches to Modify Tubulin with Biotin and DNA.

The filamentous cytoskeletal protein microtubule, a polymer of α and ß heterodimers of tubulin, plays major roles in intracellular transport as well as in vitro molecular actuation and transportation. Functionalization of tubulin dimers through covalent linkage facilitates utilization of microtubule in the nanobioengineering. Here we present a detailed description of the methodologies used to modify tubulin dimers with DNA strand and biotin through covalent interaction.

Construction of Molecular Robots from Microtubules for Programmable Swarming.

Swarm robotics has been attracting much attention in recent years in the field of robotics. This chapter describes a methodology for the construction of molecular swarm robots through precise control of active self-assembly of microtubules (MTs). Detailed protocols are presented for the construction of molecular robots through conjugation of DNA to MTs and demonstration of swarming of the MTs. The swarming is mediated by DNA-based interaction and photoirradiation which act as processors and sensors respectively for the robots. Furthermore, the required protocols to utilize the swarming of MTs for molecular computation is also described.

Magnetic Force-Induced Alignment of Microtubules by Encapsulation of CoPt Nanoparticles Using a Tau-Derived Peptide.

Construction of magnetotactic materials is a significant challenge in nanotechnology applications such as nanodevices and nanotransportation. Artificial magnetotactic materials can be designed from magnetotactic bacteria because these bacteria use magnetic nanoparticles for aligning with and moving within magnetic fields. Microtubules are attractive scaffolds to construct magnetotactic materials because of their intrinsic motility. Nonetheless, it is challenging to magnetically control their orientation while retaining their motility by conjugating magnetic nanoparticles on their outer surface. Here we solve the issue by encapsulating magnetic cobalt-platinum nanoparticles inside microtubules using our developed Tau-derived peptide that binds to their internal pockets. The in situ growth of cobalt-platinum nanoparticles resulted in the formation of a linear-chain assembly of nanoparticles inside the microtubules. The magnetic microtubules significantly aligned with a high order parameter (0.71) along the weak magnetic field (0.37 T) and showed increased motility. This work provides a new concept for designing magnetotactic materials.