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Functional microdevices based on responsive hydrogel show great promise in targeted delivery and biomedical analysis. Among state-of-the-art techniques for manufacturing hydrogel-based microarchitectures, femtosecond laser two-photon polymerization distinguishes itself by high designability and precision, but the point-by-point writing scheme requires mechanical apparatuses to support focus scanning. In this work, by predesigning holograms combined with lens phase modulation, multiple femtosecond laser spots are holographically generated and shifted for prototyping of three-dimensional shape-morphing structures without any moving equipment in the construction process. The microcage array is rapidly fabricated for high-performance target capturing enabled by switching environmental pH. Moreover, the built scaffolds can serve as arrayed analytical platforms for observing cell behaviors in normal or changeable living spaces or revealing the anticancer effects of loaded drugs. The proposed approach opens a new path for facile and flexible manufacturing of hydrogel-based functional microstructures with great versatility in micro-object manipulation.

Soft actuators and microrobots that can move spontaneously and continuously without artificial energy supply and intervention have great potential in industrial, environmental, and military applications, but still remain a challenge. Here, a bioinspired MXene-based bimorph actuator with an asymmetric layered microstructure is reported, which can harness natural sunlight to achieve directional self-locomotion. We fabricate a freestanding MXene film with an increased and asymmetric layered microstructure through the graft of coupling agents into the MXene nanosheets. Owing to the excellent photothermal effect of MXene nanosheets, increased interlayer spacing favoring intercalation/deintercalation of water molecules and its caused reversible volume change, and the asymmetric microstructure, this film exhibits light-driven deformation with a macroscopic and fast response. Based on it, a soft bimorph actuator with ultrahigh response to solar energy is fabricated, showing natural sunlight-driven actuation with ultralarge amplitude and fast response (346° in 1 s). By utilizing continuous bending deformation of the bimorph actuator in response to the change of natural sunlight intensity and biomimetic design of an inchworm to rectify the repeated bending deformation, an inchwormlike soft robot is constructed, achieving directional self-locomotion without any artificial energy and control. Moreover, soft arms for lifting objects driven by natural sunlight and wearable smart ornaments that are combined with clothing and produce three-dimensional deformation under natural sunlight are also developed. These results provide a strategy for developing natural sunlight-driven soft actuators and reveal great application prospects of this photoactuator in sunlight-driven soft biomimetic robots, intelligent solar-energy-driven devices in space, and wearable clothing.

Advanced encryption and decryption strategies are of great significance for information protection and data security. Visual optical information encryption and decryption technology plays an important role in the field of information security. However, the current optical information encryption technologies have shortcomings such as the need for external decryption equipment, the inability to read out repeatedly, and information leakage, which hinder their practical application. By combining the excellent thermal response characteristics of the MXene-isocyanate propyl triethoxy silane (IPTS)/polyethylene (PE) bilayer and the structural color generated from the laser fabricated biomimetic structural color surface, an approach of encrypt, decrypt, and transmit information has been proposed. The microgroove-induced structural color is attached to the MXene-IPTS/PE bilayer to form a colored soft actuator (CSA) to realize information encryption and decryption, and information transmission. Benefiting from the unique photon-thermal response of the bilayer actuator and the precise spectrum response of the microgroove-induced structural color, the information encryption and decryption system has the advantages of being simple and reliable, which has the potential application in the field of optical information security.

Efficient calculation of the light diffraction in free space is of great significance for tracing electromagnetic field propagation and predicting the performance of optical systems such as microscopy, photolithography, and manipulation. However, existing calculation methods suffer from low computational efficiency and poor flexibility. Here, we present a fast and flexible calculation method for computing scalar and vector diffraction in the corresponding optical regimes using the Bluestein method. The computation time can be substantially reduced to the sub-second level, which is 105 faster than that achieved by the direct integration approach (~hours level) and 102 faster than that achieved by the fast Fourier transform method (~minutes level). The high efficiency facilitates the ultrafast evaluation of light propagation in diverse optical systems. Furthermore, the region of interest and the sampling numbers can be arbitrarily chosen, endowing the proposed method with superior flexibility. Based on these results, full-path calculation of a complex optical system is readily demonstrated and verified by experimental results, laying a foundation for real-time light field analysis for realistic optical implementation such as imaging, laser processing, and optical manipulation., Optics: Calculating diffraction effects in optical technologies A fast and flexible procedure for evaluating the propagation of light in optical systems is achieved by calculating the diffraction of the light using a computational process called the Bluestein method. It yields information along the entire optical path length on both ‘scalar’ variations in the general magnitude of light waves and ‘vector’ – directional – variations. Researchers led by Jiawen Li and Dong Wu at the University of Science and Technology of China, developed the process and demonstrated that it can deliver results between 100 and 100,000 times faster than two existing alternative methods. Understanding the influence of diffraction in prevailing conditions is important for predicting the fine behaviuor of light waves. The new procedure should lead to greatly improved real-time analyses that will assist in microscopy, laser-based fabrication and optical manipulation technologies.

We propose a new, to the best of our knowledge, technique to capture single particles in real-time in a microfluidic system with controlled flow using micro-pillar traps fabricated by one-step. The micro pillars are fabricated in parallel by femtosecond multi-foci laser beams, which are generated by multiplexing gratings. As the generation process does not need integration loops, the pattern and the intensity distribution of the foci array can be controlled in real-time by changing the parameters of gratings. The real-time control of the foci array enables rapidly fabricating microtraps in the microchannel with adjustment of the pillar spaces and patterns according to the sizes and shapes of target particles. This technology provides an important step towards using platforms based on single-particle analysis, and it paves the way for the development of innovative microfluidic devices for single-cell analysis.

Cerebral small vessel disease has been linked to cognitive, psychiatric and physical disabilities, especially in the elderly. However, the underlying pathophysiology remains incompletely understood, largely due to the limited accessibility of these small vessels in the live brain. Here, we report an intravital imaging and analysis platform for high-resolution, quantitative and comprehensive characterization of pathological alterations in the mouse cerebral microvasculature. By exploiting multi-parametric photoacoustic microscopy (PAM), microvascular structure, blood perfusion, oxygenation and flow were imaged in the awake brain. With the aid of vessel segmentation, these structural and functional parameters were extracted at the single-microvessel level, from which vascular density, tortuosity, wall shear stress, resistance and associated cerebral oxygen extraction fraction and metabolism were also quantified. With the use of vasodilatory stimulus, multifaceted cerebrovascular reactivity (CVR) was characterized in vivo. By extending the classic Evans blue assay to in vivo, permeability of the blood-brain barrier (BBB) was dynamically evaluated. The utility of this enabling technique was examined by studying cerebrovascular alterations in an established mouse model of high-fat diet-induced obesity. Our results revealed increased vascular density, reduced arterial flow, enhanced oxygen extraction, impaired BBB integrity, and increased multifaceted CVR in the obese brain. Interestingly, the 'counterintuitive' increase of CVR was supported by the elevated active endothelial nitric oxide synthase in the obese mouse. Providing comprehensive and quantitative insights into cerebral microvessels and their responses under pathological conditions, this technique opens a new door to mechanistic studies of the cerebral small vessel disease and its implications in neurodegeneration and stroke.

Artificial bioinspired surfaces are attracting increasing attention because of their fascinating characteristics, such as the structural color of a butterfly wing and the anisotropic wetting of a rice leaf. However, realization of the multicolor biomimetic metal surfaces with controlled anisotropy by using a simple, inexpensive and efficient method remains a challenge. Herein, we propose a focused laser interference lithography processing method, which has sufficient energy density and high processing efficiency to directly fabricate the groove structures on the metal surface. The surface is multicolor due to the diffraction grating effect of the regular groove structures, and exhibits anisotropic wetting due to its single-direction morphology. The influence of the observation angle on the diversity of colors and the anisotropic wetting under different heights and periods of grooves have been quantitatively investigated. A variety of patterns (e.g., leaf, crab, windmill, letter and so on) can be processed on various metals (e.g., stainless steel, Ti, Ni, Cu, Fe, Zn and so on) by this focused laser interference lithography because of its excellent flexibility and wide range of suitable materials. This multi-functional metal surface has broad applications in identification code, decorative beautification, anti-counterfeiting, information storage, bionic application design and so on.

Three-dimensional helical microstructures are abundant in nature and can be applied as chiral metamaterials for advanced nanophotonics. Here we report a flexible method to fabricate double-helical microstructures with single exposure by recording the chirality of incident optical vortices. Two coaxial optical vortices can interfere to generate a helical optical field, confirmed by the numerical simulation. The diameters of double-helical microstructures can be tailored by the magnitude of topological charges. This fast manufacturing strategy provides the opportunity to efficiently yield helical microstructures. Finally, the chirality of double-helical microstructures can be reversibly read by optical vortices, demonstrating a strong chiroptical response.

Soft actuators and microrobots that can move spontaneously and continuously without artificial energy supply and intervention have great potential in industrial, environmental, and military applications, but still remain a challenge. Here, a bioinspired MXene-based bimorph actuator with an asymmetric layered microstructure is reported, which can harness natural sunlight to achieve directional self-locomotion. We fabricate a freestanding MXene film with an increased and asymmetric layered microstructure through the graft of coupling agents into the MXene nanosheets. Owing to the excellent photothermal effect of MXene nanosheets, increased interlayer spacing favoring intercalation/deintercalation of water molecules and its caused reversible volume change, and the asymmetric microstructure, this film exhibits light-driven deformation with a macroscopic and fast response. Based on it, a soft bimorph actuator with ultrahigh response to solar energy is fabricated, showing natural sunlight-driven actuation with ultralarge amplitude and fast response (346° in 1 s). By utilizing continuous bending deformation of the bimorph actuator in response to the change of natural sunlight intensity and biomimetic design of an inchworm to rectify the repeated bending deformation, an inchwormlike soft robot is constructed, achieving directional self-locomotion without any artificial energy and control. Moreover, soft arms for lifting objects driven by natural sunlight and wearable smart ornaments that are combined with clothing and produce three-dimensional deformation under natural sunlight are also developed. These results provide a strategy for developing natural sunlight-driven soft actuators and reveal great application prospects of this photoactuator in sunlight-driven soft biomimetic robots, intelligent solar-energy-driven devices in space, and wearable clothing.

Supplement 1

Dynamic and real-time monitoring of the motion state of soft actuators is of great significance for optimizing their performance. However, present noncontact measurement approaches based on diffractive groove arrays fabricated by imprinting have some limitation, e.g., the grooves should be processed before the solidification of soft materials or the depth and period of grooves cannot be flexibly adjusted. Here, a flexible and high-efficiency fabrication approach carbon-assisted laser interference lithography (CLIL) for periodical groove structures with structural color is proposed. This technique is to irradiate the interference laser on the PDMS surface coated by a carbon layer, which is used for enhanced laser absorption. The processing parameters are systematically studied and optimized to achieve a bright structural color. Benefiting from the advantages of CLIL, the structural color can be processed on a solidified transparent surface with controllable characteristics such as groove period and depth. Lastly, the motion of an electric-driven actuator can be real-time quantified by calibrating the relationship between the observation angle and the observed structural color.

The high-performance unidirectional manipulation of microdroplets is crucial for many vital applications including water collection and bioanalysis. Among several actuation methods (e.g., electric, magnetic, light, and thermal actuation), mechanical vibration is pollution-free and biocompatible. However, it suffers from limited droplet movement mode, small volume range (VMax /VMin

A ring-shaped focus, such as a focused vortex beam, has played an important role in microfabrication and optical tweezers. The shape and diameter of the ring-shaped focus can be easily adjusted by the topological charge of the vortex. However, the flow energy is also related to the topological charge, making the individual control of diameter and flow energy of the vortex beam impossible. Meanwhile, the shape of the focus of the vortex beam remains in the hollow ring. Expanding the shape of focus of structural light broadens the applications of the vortex beam in the field of microfabrication. Here, we proposed a ring-shaped focus with controllable gaps by multiplexing the vortex beam and annular beam. The multiplexed beam has several advantages, such as the diameter and flow energy of the focal point can be individually controlled and are not affected by the zero-order beam, and the gap size and position are controllable.

Superhydrophobic stimuli-responsive shape memory polymer (SMP) surfaces with tunable wettability have been extensively explored, but in situ reversibly switching ability as well as selectively capturing and releasing different liquids or bubbles, unfortunately, is still a blockage. Here, we fabricated a kind of light-responsive superhydrophobic SMP microplate array by utilizing femtosecond laser ablation and replica-mold method to achieve in situ switchable adhesion. By combining the photothermal effect of carbon black with the shape memory effect of SMP, the reversible switching between the upright state and temporary bending state of the microplate array can be readily realized. Simultaneously, the apparent force for the microplate array can be reversibly switched between low and high adhesion. More significantly, the current surface is competent for the amphibious manipulator, that is, the microplate array is adaptive for the selective capture and release of droplets as well as underwater bubbles. The current superhydrophobic SMP microplate array will have potential applications in intelligent droplet and bubble operation.

In this Letter, we propose a type of continuous phase vortex gratings (CPVGs), which are able to generate a series of vortex beams with equal or proportional diffracted energies and different topological charges (TCs). A set of CPVGs with dimensions (60 × 60 × 1.1 μm3) are directly designed by mathematical equations, which avoids the use of iterative algorithms. The CPVGs are fabricated by femtosecond laser direct writing (FsLDW) with photoresist, and the experimentally generated vortex beams are in good agreement with the theoretical designs, exhibiting high optical efficiencies. In addition, we realized a CPVG onto the tip of a composite fiber for integrated optical systems. Our work paves the way for applications in optical communications, optical manipulations, and high-performance integrated optics.

Single crystal perovskite materials with the intriguing properties of wide optical absorption range, low trap density, photoluminescence, and superior charge-transfer have emerged as a new class of revolutionary photovoltaic semiconductors promising for various applications. A technique to realize microstructures or microdevices on the surface of single crystal can facilitate the incorporation of these materials into optoelectronic applications. Here, we first reported the fabrication of 1-D mciropores, microlines, and 2-D micropatterns such as word “USTC,” number “2016” and “Olympic rings” on the surface of CH3NH3PbI3 single crystal by femtosecond laser ablating. The effect of parameters such as exposure time, laser peak intensity, and scanning speed was quantitatively investigated to determine the parameter intervals capable of ensuring the required resolution. By fabricating periodic grating microstructures, the perovskite surfaces showed bright iridescence from dark blue to red due to the grating diffraction effect. Moreover, it is found that the fluorescence peak strength of processed area obviously grows with laser peak intensity and scanning speed, which is attributed to the increasing surface roughness caused by higher laser peak intensity and slower scanning speed. These works are beneficial for researchers to better understand the intrinsic property of single crystal perovskite and accelerate perovskite-based optoelectronics applications.

Structured laser beam based microfabrication technology provides a rapid and flexible way to create some special microstructures. As an important member in the propagation of invariant structured optical fields, Mathieu beams (MBs) exhibit regular intensity distribution and diverse controllable parameters, which makes it extremely suitable for flexible fabrication of functional microstructures. In this study, MBs are generated by a phase-only spatial light modulator (SLM) and used for femtosecond laser two-photon polymerization (TPP) fabrication. Based on structured beams, a dynamic holographic processing method for controllable three-dimensional (3D) microcage fabrication has been presented. MBs with diverse intensity distributions are generated by controlling the phase factors imprinted on MBs with a SLM, including feature parity, ellipticity parameter q, and integer m. The focusing properties of MBs in a high numerical aperture laser microfabrication system are theoretically and experimentally investigated. On this basis, complex two-dimensional microstructures and functional 3D microcages are rapidly and flexibly fabricated by the controllable patterned focus, which enhances the fabrication speed by 2 orders of magnitude compared with conventional single-point TPP. The fabricated microcages act as a nontrivial tool for trapping and sorting microparticles with different sizes. Finally, culturing of budding yeasts is investigated with these microcages, which demonstrates its application as 3D cell culture scaffolds.

In the development of microfluidic systems, conventional 2D processing technologies are increasingly difficult to meet the requirement of integration of multifunctional components within a microchannel. Recently, two-photon polymerization (TPP) technology has emerged as a novel alternative to fabricate 3D microdevices functionalizing conventional microfluidic chips. Here, the development of TPP microfluidic technology comprising parallel fabrication, holographic patterning method and real-time lithography in a controlled flow is reported. And a series of functional microcomponents containing microfilters, microsorters, microtrap, tunable microlens are fabricated by above methods. The results indicate that the processing of microfluidic devices is simple, timesaving, low cost and programmable designability. The functional microchips are further used in blood cells sorting, biomedical sensing, microparticle purification and trapping with successful test results.

Blast traumatic brain injury (bTBI) is a leading contributor to combat-related injuries and death. Although substantial emphasis has been placed on blast-induced neuronal and axonal injuries, co-existing dysfunctions in the cerebral vasculature, particularly the microvasculature, remain poorly understood. Here, we studied blast-induced cerebrovascular dysfunctions in a rat model of bTBI (blast overpressure: 187.8 ± 18.3 kPa). Using photoacoustic microscopy (PAM), we quantified changes in cerebral hemodynamics and metabolism—including blood perfusion, oxygenation, flow, oxygen extraction fraction, and the metabolic rate of oxygen—4 h post-injury. Moreover, we assessed the effect of blast exposure on cerebrovascular reactivity (CVR) to vasodilatory stimulation. With vessel segmentation, we extracted these changes at the single-vessel level, revealing their dependence on vessel type (i.e., artery vs. vein) and diameter. We found that bTBI at this pressure level did not induce pronounced baseline changes in cerebrovascular diameter, blood perfusion, oxygenation, flow, oxygen extraction, and metabolism, except for a slight sO(2) increase in small veins (

Metallic mirror is the core component of the imaging system in the reflective astronomical telescope. However, because the telescopesare usually located in the wild, they are often contaminated by dust and other pollutants which will greatly reduce the imaging quality. Therefore, the surface of reflective mirror in telescope should be cleaned routinely in order to recover high performance of telescope. Currently, the artificial ice cleaning is the most common method employed in the cleaning of mirror surface, which is complicated and costly. Besides, the micron particles adhered on the surface of the mirror are especially difficult to be removed by dry ice flow when their diameters are less than 20 μ m because of the Van der Waals force between the particles and metal mirror. Moreover, an ordinary method with wipe and cleanser is also used in which the friction between wipe and mirror may damage the telescope. To overcome these shortcomings, this work proposed a laser cleaning strategy in which amplified femtosecond pulsed lasers was used to clean the reflecting mirror surface. As a new cleaning method, laser cleaning technology which is non-contact and frictionless has been applied successfully in the cleaning of industrial molds, buildings, precision machinery components. For the advantages of femtosecond laser, such as short pulse duration, small thermal effects, high pulse energy, it has been used in the cleaning of cultural relics and has good achievement in recent years. This article firstly studied the interaction between the femtosecond laser and the reflective aluminum mirror. The laser damage threshold of aluminum mirror was measured about 60 mJ/cm2, which would reduce to 57 mJ/cm2 for dirty mirror because of the microparticles adhered on the surface of reflector mirror. Then, by optimizing laser parameters including the scan rate, the scan pitch, and the laser energy, it could be found that when the laser energy density ranges from 30 to 55 mJ/cm2, micron dust particles with diameters less than 20 μ m on mirror surface could be cleaned with excellent clean effect and the reflectivity in the visible light region has been greatly improved. Finally, through the dust particles and aluminum mirror substrate spectrum analysis, we ruled out that the removed microparticles were thermal melted by laser energy. The results indicated that thermal expansion plays the key role in laser cleaning of metal mirror. This work shows that femtosecond laser cleaning has a good effect on the removing of micron particles. As a simple and easy way, femtosecond laser cleaning has a good prospect in cleaning of astronomical telescope.

Rationale: Emerging evidence has suggested that sphingosine 1-phosphate (S1P), a bioactive metabolite of sphingolipids, may play an important role in the pathophysiological processes of cerebral hypoxia and ischemia. However, the influence of S1P on cerebral hemodynamics and metabolism remains unclear. Material and Methods: Uniquely capable of high-resolution, label-free, and comprehensive imaging of hemodynamics and oxygen metabolism in the mouse brain without the influence of general anesthesia, our newly developed head-restrained multi-parametric photoacoustic microscopy (PAM) is well suited for this mechanistic study. Here, combining the cutting-edge PAM and a selective inhibitor of sphingosine kinase 2 (SphK2) that can increase the blood S1P level, we investigated the role of S1P in cerebral oxygen supply-demand and its neuroprotective effects on global brain hypoxia induced by nitrogen gas inhalation and focal brain ischemia induced by transient middle cerebral artery occlusion (tMCAO). Results: Inhibition of SphK2, which increased the blood S1P, resulted in the elevation of both arterial and venous sO2 in the hypoxic mouse brain, while the cerebral blood flow remained unchanged. As a result, it gradually and significantly reduced the metabolic rate of oxygen. Furthermore, pre-treatment of the mice subject to tMCAO with the SphK2 inhibitor led to decreased infarct volume, improved motor function, and reduced neurological deficit, compared to the control treatment with a less potent R-enantiomer. In contrast, post-treatment with the inhibitor showed no improvement in the stroke outcomes. The failure for the post-treatment to induce neuroprotection was likely due to the relatively slow hemodynamic responses to the SphK2 inhibitor-evoked S1P intervention, which did not take effect before the brain injury was induced. Conclusions: Our results reveal that elevated blood S1P significantly changes cerebral hemodynamics and oxygen metabolism under hypoxia but not normoxia. The improved blood oxygenation and reduced oxygen demand in the hypoxic brain may underlie the neuroprotective effect of S1P against ischemic stroke. This work was supported in part by the National Institutes of Health (NS099261 to SH and GM121075 to KRL/WLS) and the American Heart Association (15SDG25960005 to SH).

Multilayered microfluidic channels integrated with functional microcomponents are the general trend of future biochips, which is similar to the history of Si-integrated circuits from the planer to the three-dimensional (3D) configuration, since they offer miniaturization while increasing the integration degree and diversifying the applications in the reaction, catalysis, and cell cultures. In this paper, an optimized hybrid processing technology is proposed to create true multilayered microchips, by which “all-in-one” 3D microchips can be fabricated with a successive procedure of 3D glass micromachining by femtosecond-laser-assisted wet etching (FLAE) and the integration of microcomponents into the fabricated microchannels by two-photon polymerization (TPP). To create the multilayered microchannels at different depths in glass substrates (the top layer was embedded at 200 μm below the surface, and the underlying layers were constructed with a 200-μm spacing) with high uniformity and quality, the laser power density (13~16.9 TW/cm2) was optimized to fabricate different layers. To simultaneously complete the etching of each layer, which is also important to ensure the high uniformity, the control layers (nonlaser exposed regions) were prepared at the upper ends of the longitudinal channels. Solvents with different dyes were used to verify that each layer was isolated from the others. The high-quality integration was ensured by quantitatively investigating the experimental conditions in TPP, including the prebaking time (18~40 h), laser power density (2.52~2.94 TW/cm2) and developing time (0.8~4 h), all of which were optimized for each channel formed at different depths. Finally, the eight-layered microfluidic channels integrated with polymer microstructures were successfully fabricated to demonstrate the unique capability of this hybrid technique., Microfluidics: 3D chips to power next-gen experiments Newly-developed manufacturing technologies enable the construction of powerful microfluidics chips. Just as how silicon computer chips leaped in capability thanks to the development of three-dimensional circuitry, microfluidics chips—which conduct experiments on liquids in micrometer-sized channels—stand to benefit from the same development. Researchers led by Dong Wu, from the University of Science and Technology of China, and Koji Sugioka, from Japan’s RIKEN Center for Advanced Photonics, developed a methodology that leverages femtosecond laser pulses to fabricate multi-layer glass microfluidics channels. The team validated their process by creating an eight-layered glass microfluidics device with layers of channels separated by just 200 µm. 3D microfabrication technologies such as this have the capacity to enable point-of-care diagnostics, the modeling of multiple organ systems, and complex studies involving particle mixing and separation.

Capable of mediating efficient transfection and protein production without eliciting innate immune responses, chemically modified mRNA holds great potential to produce paracrine factors at a physiologically beneficial level, in a spatiotemporally controlled manner, and with low toxicity. Although highly promising in cardiovascular medicine and wound healing, effects of this emerging therapeutic on the microvasculature and its bioactivity in disease settings remain poorly understood. Here, we longitudinally and comprehensively characterize microvascular responses to AZD8601, a modified mRNA encoding vascular endothelial growth factor A (VEGF-A), in vivo. Using multi-parametric photoacoustic microscopy, we show that intradermal injection of AZD8601 formulated in a biocompatible vehicle results in pronounced, sustained and dose-dependent vasodilation, blood flow upregulation, and neovessel formation, in striking contrast to those induced by recombinant human VEGF-A protein, a non-translatable variant of AZD8601, and citrate/saline vehicle. Moreover, we evaluate the bioactivity of AZD8601 in a mouse model of diabetic wound healing in vivo. Using a boron nanoparticle-based tissue oxygen sensor, we show that sequential dosing of AZD8601 improves vascularization and tissue oxygenation of the wound bed, leading to accelerated re-epithelialization during the early phase of diabetic wound healing.

In this Letter, we demonstrate the observation of colorful Airy beams and Airy imaging of letters, which we called Airy letters here, generated through the continuous cubic phase microplate (CCPP) elaborately fabricated by femtosecond laser two-photon processing. The fabricated CCPP with both micro size (60 μm×60 μm×1.1 μm) and continuous variation of phase shows a good agreement with the designed CCPP. Chromatic Airy beams and Airy letters "USTC" are experimentally generated via the CCPP illuminated by white light. In addition, superior properties of Airy letters are explored, demonstrating that the Airy letters inherit the nondiffraction, self-healing, and transverse acceleration characteristics of Airy beams. Our work paves the way toward integrated optics, light separation, optical imaging, and defective information recovery.

Presents corrections to the paper, "Femtosecond laser direct ablating micro/nanostructures and micropatterns on CH3NH3PbI3 single crystal" (Wang, C.W., et al), IEEE Photon. J., vol. 9, no. 2, Apr. 2017, Art. no. 2400110.

Uniform oriented ripples were induced on stainless steel surface by polarized femtosecond laser. Multiple patterns were successfully encoded with the different oriented ripples on the surface without spatial overlap. Each pattern can be selectively displayed with structural color while the others cannot be in the meantime when white light is irradiated on the surface from different directions. The influence of ripples with different periods for selecting pattern is also investigated. The ripple period is crucial to the color effects. This approach can be used in the fields of color display, identifying codes and anti-counterfeiting patterns.

Conventional micropore membranes based size sorting have been widely applied for single-cell analysis. However, only a single filtering size can be achieved and the clogging issue cannot be completely avoided. Here, we propose a novel arch-like microsorter capable of multimodal (high-, band- and low-capture mode) sorting of particles. The target particles can pass through the front filter and are then trapped by the back filter, while the non-target particles can bypass or pass through the microsorter. This 3D arch-like microstructures are fabricated inside a microchannel by femtosecond laser parallel multifocal scanning. The designed architecture allows for particles isolation free of clogging over 20 minutes. Finally, as a proof of concept demonstration, SUM159 breast cancer cells are successfully separated from whole blood.

The femtosecond laser color marking stainless steel surfaces with different incident wavelengths were investigated theoretically and experimentally. It indicates that the spectral regions of the colors firstly increase and then reduce with increasing spatial periods of the ripples induced by laser irradiation. Additionally, the colors are gradually changed from blue to red due to the elongation of the diffracted light wavelengths. As a result, the color effects are distinctly different. This study offers a new controllable parameter to produce diverse colors, which may find a wide range of applications in the laser color marking, art designing and so on.

The development of a high-efficiency projection two-photon polymerization (P2PP) process by using a liquid crystal spatial light modulator (SLM) is presented. Rapid fabrication of 2D patterned microstructures with P2PP is demonstrated, and the effect of laser pattern and exposure dose on the surface roughness of the fabricated microstructures is investigated. It is found that the distribution of laser intensity at the focal plane of objective has a significant effect on the profiles of microstructures. This unique technology has a promising approach to increase the efficiency of two-photon polymerization (2PP) and a parallel fabrication of complex 2D and 3D microstructures.

Enhanced colors can be formed when white light is irradiated on the surface ripples induced by femtosecond laser. In this paper, we have demonstrated the ability to display the diverse colors by simultaneously adjusting the incident white light angle and the ripples orientation. Furthermore, our investigation revealed that multi-patterns constituted by ripples with different orientations could be designed on metal surfaces. The diverse display for the desired ones can be realized by exquisitely varying the incident light angle and rotating sample angle. More interestingly, it is found that, although the same patterns could be displayed under different conditions, the colors might be different. These findings can provide a novel method to carry and identify high quantity of information, which may find potential applications in the fields of information storage, identifying codes and anti-counterfeiting patterns.

Long microchannels with thin walls, small width, and nanoholes or irregular shaped microgaps, which are similar to capillaries or cancerous vessels, are urgently needed to simulate the physiological activities in human body. However, the fabrication of such channels remains challenging. Here, microchannels with designable holes are manufactured by combining laser printing with line-contact capillary-force assembly. Two microwalls are first printed by femtosecond laser direct-writing, and subsequently driven to collapse into a channel by the capillary force that arises in the evaporation of developer. The channel can remain stable in solvent due to the enhanced Van der Waals' force caused by the line-contact of microwalls. Microchannels with controllable nanoholes and almost arbitrary patterns can be fabricated without any bonding or multistep processes. As-prepared microchannels, with wall thicknesses less than 1 µm, widths less than 3 µm, lengths more than 1 mm, are comparable with human capillaries. In addition, the prepared channels also exhibit the ability to steer the flow of liquid without any external pump.

Rapid integration of high-quality functional devices in microchannels is in highly demand for miniature lab-on-a-chip applications. This paper demonstrates the embellishment of existing microfluidic devices with integrated micropatterns via femtosecond laser MRAF-based holographic patterning (MHP) microfabrication, which proves two-photon polymerization (TPP) based on spatial light modulator (SLM) to be a rapid and powerful technology for chip functionalization. Optimized mixed region amplitude freedom (MRAF) algorithm has been used to generate high-quality shaped focus field. Base on the optimized parameters, a single-exposure approach is developed to fabricate 200 × 200 μm microstructure arrays in less than 240 ms. Moreover, microtraps, QR code and letters are integrated into a microdevice by the advanced method for particles capture and device identification. These results indicate that such a holographic laser embellishment of microfluidic devices is simple, flexible and easy to access, which has great potential in lab-on-a-chip applications of biological culture, chemical analyses and optofluidic devices.

High efficiency fabrication and integration of three-dimension (3D) functional devices in Lab-on-a-chip systems are crucial for microfluidic applications. Here, a spatial light modulator (SLM)-based multifoci parallel femtosecond laser scanning technology was proposed to integrate microstructures inside a given ‘Y’ shape microchannel. The key novelty of our approach lies on rapidly integrating 3D microdevices inside a microchip for the first time, which significantly reduces the fabrication time. The high quality integration of various 2D-3D microstructures was ensured by quantitatively optimizing the experimental conditions including prebaking time, laser power and developing time. To verify the designable and versatile capability of this method for integrating functional 3D microdevices in microchannel, a series of microfilters with adjustable pore sizes from 12.2 μm to 6.7 μm were fabricated to demonstrate selective filtering of the polystyrene (PS) particles and cancer cells with different sizes. The filter can be cleaned by reversing the flow and reused for many times. This technology will advance the fabrication technique of 3D integrated microfluidic and optofluidic chips.

In this Letter, we present a light field regulation method to form a ring light field with controllable density distribution. This method is to compress the phase modulation depth of Bessel holograms superimposed with blazed gratings and tune the diffraction efficiency of the superimposed holograms by gray scale. The experimental light field generated by the superimposed holograms is consistent with the simulation results. By designing the phase modulation depth of the superimposed holograms with different parameters, ring light fields with suitable intensity distribution are obtained, and the fabrication of ring microstructure with uniform wall thickness is realized. Finally, as a special case of processing, dynamic holographic processing of high-aspect-ratio microtubes with variable diameter and uniform wall thickness is demonstrated.