Abstract
In this work, we report a novel soft diffractive micro-optics, called ‘microscale kinoform phase-type lens (micro-KPL)’, which is fabricated by femtosecond laser direct writing (FsLDW) using bovine serum albumin (BSA) as building blocks and flexible polydimethylsiloxane (PDMS) slices as substrates. By carefully optimizing various process parameters of FsLDW (e.g., average laser power density, scanning step, exposure time on a single point and protein concentration), the as-formed protein micro-KPLs exhibit excellent surface quality, well-defined three-dimensional (3D) geometry and distinctive optical properties, even in relatively harsh operation environments (for instance, in strong acid or base). Laser shaping, imaging and other optical performances can be easily achieved. More importantly, micro-KPLs also have unique flexible and stretchable properties as well as good biocompatibility and biodegradability. Therefore, such protein hydrogel-based micro-optics may have great potential applications, such as in flexible and stretchable photonics and optics, soft integrated optical microsystems and bioimplantable devices. Scientists have used direct laser writing to fabricate flexible and biocompatible optical elements from a protein hydrogel. Yun-Lu Sun and co-workers from Jilin University in China and Pohang University of Science and Technology in Korea say that the miniature optical components produced using this approach could be useful for use in photonic implants or as stretchable optical devices. They fabricated soft, phase-type diffractive lenses with diameters of 50–100 µm by focusing femtosecond pulses from a Ti:sapphire laser into an aqueous ‘protein ink’ comprising a mixture of bovine serum albumin and the photosensitizer methylene blue. Irradiated regions underwent two-photon polymerization to form a soft protein hydrogel. By moving both the laser beam and the sample, the researchers successfully fabricated a three-dimensional optic featuring the desired series of concentric rings needed to act as a phase-type lens.
Highlights
To demonstrate the focusing and shaping performance of the laser, the protein micro-KPL was immersed in Rhodamine B aqueous solution; the laser beam was directed through the micro-KPL into the solution
In summary, a novel soft and biodegradable protein micro-KPL has been fabricated on PDMS matrixes by a home-made FsLDW system
As-formed protein micro-KPLs have excellent flexibility and stretchability, and their optical properties were not damaged after repeated stretching or bending
Summary
It has been demonstrated that biocompatible proteinSoft micro-optics, which can be twisted, folded, compressed and micro/nanoscale structures and devices (e.g., micro-optics) could be stretched repeatedly without any significant damage to mechanical successfully fabricated by FsLDW techniques.[25–31] Due to the low or optical characteristics, have become increasingly important in applications such as adaptive microlenses,[1] paper-like displays,[2,3] solar cells,[4,5,6] photonic integrated systems[7,8] and, most notably, bio-integrated and bio-implantable photonic micro/nanodevices.[9,10,11,12,13,14,15,16,17] Until now, numerous fabrication methods, for instance, transferring-andcollateral damage of FsLDW, which achieved by high spacial restriction of the laser energy and a Fs-scale pulse width that is much shorter than the thermal diffusion time, these protein microstructures exhibit unique bioactivities,[25] good biocompatibility and good tunability under appropriate external stimuli.[26,27] the quality of proprinting processes, hot-embossing technique, nano-imprinting, and tein micro-optics has been highly improved by optimized laser proself-assembly approaches, have been developed to produce flexible cessing and the self-smoothing effect after two-photon-induced and stretchable micro-optics using organic, polymer, silk or hydrogel polymerization, which ensures their high performance optical promaterials.[13–20] Owing to their abundance, renewability, inexpensive- perties.[26,27] Despite the significant progress that has been achieved ness, degradability, biocompatibility and unique functionality, pro- to date, the existing protein micro-optics have not taken full advantage tein-based soft micro-optics demonstrate superior performances of their soft features (both flexibility and stretchability) and have not that exceed many devices made from currently available organic mate- been applied as soft micro-optics, which limits their further rials. Developing a convenient, economic and ecofriendly applications For this reason, in this work, we will report a soft diffabrication strategy that could readily produce high-performance pro- fractive micro-optics, called ‘microscale kinoform phase-type lenses tein-based soft micro-optics with high accuracy and improved quality (micro-KPL)’, fabricated by FsLDW using bovine serum albumin is challenging. In this work, we will report a soft diffabrication strategy that could readily produce high-performance pro- fractive micro-optics, called ‘microscale kinoform phase-type lenses tein-based soft micro-optics with high accuracy and improved quality (micro-KPL)’, fabricated by FsLDW using bovine serum albumin is challenging Toward this end, the novel femtosecond laser direct (BSA) as building blocks and flexible polydimethylsiloxane (PDMS)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
