Dimension‐Controllable Microtube Arrays by Dynamic Holographic Processing as 3D Yeast Culture Scaffolds for Asymmetrical Growth Regulation

Abstract

Transparent microtubes can function as unique cell culture scaffolds, because the tubular 3D microenvironment they provide is very similar to the narrow space of capillaries in vivo. However, how to realize the fabrication of microtube-arrays with variable cross-section dynamically remains challenging. Here, a dynamic holographic processing method for producing high aspect ratio (≈20) microtubes with tunable outside diameter (6-16 µm) and inside diameter (1-10 µm) as yeast culture scaffolds is reported. A ring-structure Bessel beam is modulated from a typical Gaussian-distributed femtosecond laser beam by a spatial light modulator. By combining the axial scanning of the focused beam and the dynamic display of holograms, dimension-controllable microtube arrays (straight, conical, and drum-shape) are rapidly produced by two-photon polymerization. The outside and inside diameters, tube heights, and spatial arrangements are readily tuned by loading different computer-generated holograms and changing the processing parameters. The transparent microtube array as a nontrivial tool for capturing and culturing the budding yeasts reveals the significant effect of tube diameter on budding characteristics. In particular, the conical tube with the inside diameter varying from 5 to 10 µm has remarkable asymmetrical regulation on the growth trend of captured yeasts.

Stimuli-Responsive Actuator Fabricated by Dynamic Asymmetric Femtosecond Bessel Beam for In Situ Particle and Cell Manipulation

“…The liquid-crystal SLM is a pure phase modulator in the range of gray level (0–255), and 0 to 255 gray scale value represents 0 to 2π phase delay linearly on the hologram. After reflected from SLM, imprinted with the computer-generated-hologram (CGH), a Gaussian laser femtosecond beam (central wavelength λ = 800 nm with pulse repetition rate 80 MHz and pulse width 75 fs) can be modulated to a ring-structure Bessel beam . As illustrated in Figure b, the CGH is composed of a spiral phase plate (SPP), an axicon, a blazed grating (BG), and a local phase modulation (LPM).…”

“…Among these structured beams, Bessel beams have drawn extensive attention due to their nondiffracting and self-healing properties. Ring-shaped microtubes with different diameters have been fabricated using high-order Bessel beams . What’s more, by compressing the holograms phase depth, a ring light field with controllable intensity is utilized to process variable cross-section microtubes .…”

Rapid fabrication of microrings with complex cross section using annular vortex beams

“…Until now, some very specific distributions, including Bessel beams [4] , spatially shifted vortex beams [5] , double-helix beams [6] , and ring-shaped beams [7] , have been explored for parallelization of the direct laser writing or even single-shot microfabrication. Among these methods, Bessel beams [8] and vortex beams [9,10] have been widely applied to generate ring-shaped foci. With the flexible control of parameters of Bessel and vortex beams, the diameter of ring-shaped focus can be easily adjusted.…”

Rapid Fabrication of Continuous Surface Fresnel Microlens Array by Femtosecond Laser Focal Field Engineering

“…However, the traditional point-by-point scanning usually takes a long time, thus it is difficult to fabricate large-sized structures or arrays. Therefore, various solutions have been proposed to speed up the process, for example, the focal field engineering [18][19][20][21][22], the multi-focus generation for parallel processing [23][24][25], and the multi-beam interference [26,27] for specific periodic structures.…”