Radial alignment of microtubules through tubulin polymerization in an evaporating droplet

Abstract

We report the formation of spherulites from droplets of highly concentrated tubulin solution via nucleation and subsequent polymerization to microtubules (MTs) under water evaporation by heating. Radial alignment of MTs in the spherulites was confirmed by the optical properties of the spherulites observed using polarized optical microscopy and fluorescence microscopy. Temperature and concentration of tubulins were found as important parameters to control the spherulite pattern formation of MTs where evaporation plays a significant role. The alignment of MTs was regulated reversibly by temperature induced polymerization and depolymerization of tubulins. The formation of the MTs patterns was also confirmed at the molecular level from the small angle X-ray measurements. This work provides a simple method for obtaining radially aligned arrays of MTs.

Drying of bio-colloidal sessile droplets: Advances, applications, and perspectives

“…These microtubules are also aligned radially and can be tuned by temperature-induced polymerization and depolymerization. Interestingly, this structure is also optically birefringent [65].…”

“…The dependence of the tubulin length as a function of drying rate has not been explored yet, but might give rise to different drying-induced morphological patterns. The diameter of the central hollow core is ∼15 nm, and the wall is ∼5 nm thick [65].…”

“…FIG.7. Dried morphological patterns for proteins: (I) Collagen imaged at (a-c) different locations, adopted from[102], (II) Aβ42 peptide and its seven different variants with a single point mutation, adopted from[107], (III) (a) casein micelles (observed in the form of native phosphocaseinates), and (b) whey proteins (observed in the form of isolates), adopted from[111], and (IV) Microtubules under (a) 2×, (b) 4×, adopted from[65],…”

Time-Lapse Quantitative Analysis of Drying Patterns and Machine Learning for Classifying Abnormalities in Sessile Blood Droplets

“…This uniqueness is due to multi-facet phenomena such as Marangoni convection, capillary flow, mass transport, mechanical stress, colloid-colloid, and colloid-substrate interactions within the droplet as it dries [2]. So far, diverse patterns have been reported not only for colloids such as from polymers [3-7], to liquid crystals [8, 9]; but also for fluids containing various biological colloids such as from DNA [10-12], collagen [13, 1], and microtubules [15], to proteins [16, 17], all the way to microbes such as bacteria [18, 19], algae [20], and nematode worms [21]. These previous reports show that the patterns of such droplets are extremely sensitive not only to how they are dried but also to the initial state of the fluids before drying.…”

Patterns in Dried Droplets to Detect Unfolded BSA

“…The occurrence of patterns in deposits is a frequent phenomenon that emerges in drying droplets with nonvolatile species [ 19 , 20 , 21 , 22 ]. The literature reveals that the coffee ring can appear in both simple and complex droplet systems [ 23 , 24 , 25 , 26 ].…”