Responsive Liquid Crystal Network Microstructures with Customized Shapes and Predetermined Morphing for Adaptive Soft Micro-Optics.

Stimuli-responsive materials have garnered substantial interest in recent years, particularly liquid crystal networks (LCNs) with sophisticatedly designed structures and morphing capabilities. Extensive efforts have been devoted to LCN structural designs spanning from two-dimensional (2D) to three-dimensional (3D) configurations and their intricate morphing behaviors through designed alignment. However, achieving microscale structures and large-area preparation necessitates the development of novel techniques capable of facilely fabricating LCN microstructures with precise control over both overall shape and alignment, enabling a 3D-to-3D shape change. Herein, a simple and cost-effective in-cell soft lithography (ICSL) technique is proposed to create LCN microstructures with customized shapes and predesigned morphing. The ICSL technique involves two sequential steps: fabricating the desired microstructure as the template by using the photopolymerization-induced phase separation (PIPS) method and reproducing the LCN microstructures through templating. Meanwhile, surface anchoring is employed to design and achieve molecular alignment, accommodating different deformation modes. With the proposed ICSL technique, cylindrical and spherical microlens arrays (CMLAs and SMLAs) have been successfully fabricated with stimulus-driven polarization-dependent focusing effects. This technique offers distinct advantages including high customizability, large-area production, and cost-effectiveness, which pave a new avenue for extensive applications in different fields, exemplified by adaptive soft micro-optics and photonics.

Light-driven phase transition of diffractive optical elements based on liquid crystal elastomers.

Diffractive optical element is advantageous for miniaturization, arraying and integration of optical systems. They have been widely used in beam shaping, diffractive imaging, generating beam arrays, spectral optimization and other aspects. Currently, the vast majority of diffractive optics are not tunable. This limits the applicability and functionality of these devices. Here we report a tunable diffractive optical element controlled by light in the visible band. The diffractive optical element consists of a square gold microarray deposited on a deformable substrate. The substrate is made of a liquid crystal elastomer. When pumped by a 532 nm laser, the substrate is deformed to change the crystal lattice. This changes the far-field diffraction pattern of the device. The proposed concept establishes a light-controlled soft platform with great potential for tunable/reconfigurable photonic devices, such as filters, couplers, holograms and structural color displays.

Injectable Nanocomposite Hydrogels with Strong Antibacterial, Osteoinductive, and ROS-Scavenging Capabilities for Periodontitis Treatment.

Injectable antibacterial and osteoinductive hydrogels have received considerable attention for promoting bone regeneration owing to their versatile functionalities. However, a current hydrogel with antibacterial, osteoinductive, and antioxidant properties by a facile method for periodontitis treatment is still missing. To overcome this issue, we designed an injectable hydrogel system (GPM) composed of gelatin, Ti3C2Tx MXene nanosheets, and poly-l-lysine using a simple enzymatic cross-linking technique. Physicochemical characterization demonstrated that the GPM hydrogel matrix exhibited excellent stability, moderate tissue adhesion ability, and good mechanical behavior. The GPM hydrogels significantly inhibited the growth of Porphyromonas gingivalis, scavenged reactive oxygen species, attenuated inflammatory responses, and enhanced bone tissue regeneration. Intriguingly, the arrangement of the junctional epithelium, alveolar bone volume, and alveolar bone height in the GPM-treated periodontal disease group recovered to that of the healthy group. Therefore, our injectable hydrogel system with versatile functions may serve as an excellent tissue scaffold for the treatment of periodontitis.

Tricarboxylic Acid Cycle Metabolite-Coordinated Biohydrogels Augment Cranial Bone Regeneration Through Neutrophil-Stimulated Mesenchymal Stem Cell Recruitment and Histone Acetylation-Mediated Osteogenesis.

Cranial bone defects remain a major clinical challenge, increasing patients' life burdens. Tricarboxylic acid (TCA) cycle metabolites play crucial roles in facilitating bone tissue regeneration. However, the development of TCA cycle metabolite-modified biomimetic grafts for skull bone regeneration still needs to be improved. The mechanism underlying the release of TCA cycle metabolites from biomaterials in regulating immune responses and mesenchymal stem cell (MSC) fate (migration and differentiation) remains unknown. Herein, this work constructs biomimetic hydrogels composed of gelatin and chitosan networks covalently cross-linked by genipin (CGG hydrogels). A series of TCA cycle metabolite-coordinated CGG hydrogels with strong mechanical and antiswelling performances are subsequently developed. Remarkably, the citrate (Na3Cit, Cit)-coordinated CGG hydrogels (CGG-Cit hydrogels) with the highest mechanical modulus and strength significantly promote skull bone regeneration in rat and murine cranial defects. Mechanistically, using a transgenic mouse model, bulk RNA sequencing, and single-cell RNA sequencing, this work demonstrates that CGG-Cit hydrogels promote Gli1+ MSC migration via neutrophil-secreted oncostatin M. Results also indicate that citrate improves osteogenesis via enhanced histone H3K9 acetylation on osteogenic master genes. Taken together, the immune microenvironment- and MSC fate-regulated CGG-Cit hydrogels represent a highly efficient and facile approach toward skull bone tissue regeneration with great potential for bench-to-bedside translation.

Nanosphere Lithography-Enabled Hybrid Ag-Cu Surface-Enhanced Raman Spectroscopy Substrates with Enhanced Absorption of Excitation Light.

We demonstrated a low-cost, highly sensitive hybrid Ag-Cu substrate with enhanced absorption for the excitation laser beam via the nanosphere lithography technique. The hybrid Ag-Cu surface-enhanced Raman spectroscopy (SERS) substrate consists of a Cu nanoarray covered with Ag nanoparticles. The geometry of the deposited Cu nanoarray is precisely determined through a self-assembly nanosphere etching process, resulting in optimized absorption for the excitation laser beam. Further Raman enhancement is achieved by incorporating plasmonic hotspots formed by dense Ag nanoparticles, grown by immersing the prepared Cu nanoarray in a silver nitrate solution. The structural design enables analytical enhancement factor of hybrid Ag-Cu SERS substrates of 1.13 × 105. The Ag-Cu SERS substrates exhibit a highly sensitive and reproducible SERS activity, with a low detection limit of 10-13 M for Rhodamine 6G detection and 10-9 M for 4,4'-Bipyridine. Our strategy could pave an effective and promising approach for SERS-based rapid detection in biosensors, environmental monitoring and food safety.

Divalent Anion-Induced Biohydrogels with High Strength, Anti-swelling, and Bioactive Capability for Enhanced Skull Bone Regeneration.

Increased intracranial pressure after traumatic brain injury (TBI) is an urgent problem in clinical practice. A pliable hydrogel is preferred for cranioplasty applications after TBI since it can protect brain tissue and promote bone healing. Nevertheless, biohydrogels for cranial bone regeneration still face challenges of poor mechanical properties, large swelling ratios, and low osteogenesis activity. Herein, inspired by Hofmeister effects, biopolymer hydrogels composed of protein and polysaccharides were treated with a Hofmeister series including a series of monovalent and divalent anions. Our results reveal that the divalent anion-cross-linked biohydrogels exhibit stronger mechanical properties and lower swelling ratios compared with monovalent-anion treated gels. Intriguingly, the divalent HPO42- anion induced biohybrid hydrogels with excellent mechanical behaviors (3.7 ± 0.58 MPa, 484 ± 76.7 kPa, and 148.3 ± 6.85 kJ/m3), anti-swelling capability (16.7%), and gradual degradation ability, significantly stimulating osteogenic differentiation and in vivo cranial bone regeneration. Overall, this study may provide new insights into the design of biomimetic hydrogels for treating cranial bone defects after TBI.

Toward Earth system modeling with resolved clouds and ocean submesoscales on heterogeneous many-core HPCs.

With the aid of the newly developed 'Sunway' heterogeneous-architecture supercomputer, which has world-leading HPC (high-performance computer) capability, a series of high-resolution coupled Earth system models (SW-HRESMs) with up to 5 km of atmosphere and 3 km of ocean have been developed. These models can meet the needs of multiscale interaction studies with different computational costs. Here we describe the progress of SW-HRESMs development, with an overview of the major advancements made by the international Earth science community in HR-ESMs. We also show the preliminary results of SW-HRESMs with regard to capturing major weather-climate extremes in the atmosphere and ocean, stressing the importance of permitted clouds and ocean submesoscale eddies in modeling tropical cyclones and eddy-mean flow interactions, and paving the way for further model development to resolve finer scales with even higher resolution and more realistic physics. Finally, in addition to increasing model resolution, the development procedure for a non-hydrostatic cloud and ocean submesoscale resolved ESM is discussed, laying out the major scientific directions of such a huge modeling advancement.

Roles of the cytoskeleton in human diseases.

Recently, researches have revealed the key roles of the cytoskeleton in the occurrence and development of multiple diseases, suggesting that targeting the cytoskeleton is a viable approach for treating numerous refractory diseases. The cytoskeleton is a highly structured and complex network composed of actin filaments, microtubules, and intermediate filaments. In normal cells, these three cytoskeleton components are highly integrated and coordinated. However, the cytoskeleton undergoes drastic remodeling in cytoskeleton-related diseases, causing changes in cell polarity, affecting the cell cycle, leading to senescent diseases, and influencing cell migration to accelerate cancer metastasis. Additionally, mutations or abnormalities in cytoskeletal proteins and their related proteins are closely associated with several congenital diseases. Therefore, this review summarizes the roles of the cytoskeleton in cytoskeleton-related diseases as well as its potential roles in disease treatment to provide insights regarding the physiological functions and pathological roles of the cytoskeleton.

Multiscale design of stiffening and ROS scavenging hydrogels for the augmentation of mandibular bone regeneration.

Although biomimetic hydrogels play an essential role in guiding bone remodeling, reconstructing large bone defects is still a significant challenge since bioinspired gels often lack osteoconductive capacity, robust mechanical properties and suitable antioxidant ability for bone regeneration. To address these challenges, we first engineered molecular design of hydrogels (gelatin/polyethylene glycol diacrylate/2-(dimethylamino)ethyl methacrylate, GPEGD), where their mechanical properties were significantly enhanced via introducing trace amounts of additives (0.5 wt%). The novel hybrid hydrogels show high compressive strength (>700 kPa), stiff modulus (>170 kPa) and strong ROS-scavenging ability. Furthermore, to endow the GPEGD hydrogels excellent osteoinductions, novel biocompatible, antioxidant and BMP-2 loaded polydopamine/heparin nanoparticles (BPDAH) were developed for functionalization of the GPEGD gels (BPDAH-GPEGD). In vitro results indicate that the antioxidant BPDAH-GPEGD is able to deplete elevated ROS levels to protect cells viability against ROS damage. More importantly, the BPDAH-GPEGD hydrogels have good biocompatibility and promote the osteo differentiation of preosteoblasts and bone regenerations. At 4 and 8 weeks after implantation of the hydrogels in a mandibular bone defect, Micro-computed tomography and histology results show greater bone volume and enhancements in the quality and rate of bone regeneration in the BPDAH-GPEGD hydrogels. Thus, the multiscale design of stiffening and ROS scavenging hydrogels could serve as a promising material for bone regeneration applications.

Application of gelatin methacryloyl/minocycline-chitosan-nanoparticles composite hydrogel for the treatment of periodontitis.

OBJECTIVES: This study aimed to investigate the feasibility of gelatin methacryloyl (GelMA) hydrogel loa-ded with minocycline-chitosan-nanoparticles (MCN) for the treatment of periodontitis in vitro and vivo. METHODS: MCN were synthesized by ionic gel method. GelMA/MCN composite hydrogels were prepared by compounding MCN with GelMA hydrogel. The materials were characterized by transmission electron microscope, scanning electron microscopy, and Fourier transform infrared spectroscopy. The degradation behavior and drug release rates of hydrogels were evaluated. The antibacterial activity of GelMA/MCN hydrogel against Porphyromonas gingivalis was detected, and the minimum antibacterial concentration was determined. Biocompatibility and osteogenic experiments were conducted under a simulated periodontitis environment. A rat model of periodontitis was constructed to observe the therapeutic effects of GelMA/MCN hydrogel. RESULTS: MCN was successfully synthesized with a particle size of about 80 nm, while the structures of GelMA/MCN had no significant differences from GelMA. MCN and GelMA/MCN released minocycline slowly and steadily. Bacterial growth was completely inhibited when the MCN concentration was higher than or equal to 0.2 mg·mL-1. GelMA/MCN hydrogels exhibited good biocompatibility at effective antimicrobial concentrations under the simulated periodontitis environment with the enzyme. The in vivo results showed that GelMA/MCN prevented the progression of periodontitis and promoted the repair of bone defects. CONCLUSIONS: GelMA/MCN composite hydrogel can release minocycline slowly and steadily and has good antibacterial activity and biocompatibility to promote the repair of periodontitis bone defects.

PLPP2: Potential therapeutic target of breast cancer in PLPP family.

PLPPs (Phospholipid phosphatases) are widely expressed in different human tissues, regulate cell signal transduction, and are overexpressed in cancers such as gliomas, pancreatic adenocarcinoma, lung adenocarcinoma, and so on. As a member of the PLPP family, PLPP2 (phospholipid phosphatase 2) plays a vital role in the occurrence and development of breast cancer, but its mechanism is still unclear. Our research found that PLPP2 was overexpressed in breast cancer, and the higher expression level of PLPP2 showed a worse prognosis for breast cancer patients. Further analysis showed that overexpression of PLPP2 affected the expression of CDC34 (cell-division cycle 34), LSM7 (Like-Smith 7), and SGTA (small glutamine-rich tetratricopeptide repeat-containing protein alpha) through EMT (epigenetic-mesenchymal transition) related pathways to promote the occurrence and development of breast cancer. In vitro, silencing PLPP2 significantly reduced the proliferation, invasion, and migration abilities of human breast cancer cells MDA-MB-231. ER+ is a common subtype of breast cancer. Furthermore, we found that the overexpression of PLPP2 was significantly related to the poor prognosis of ER+ breast cancer. These results indicate that PLPP2 has value as a potential therapeutic target for breast cancer, especially for ER+ breast cancer.

Role of TRPV1 ion channel in cervical squamous cell carcinoma genesis.

The transient receptor potential (TRP) family is a widely expressed superfamily of ion channels that regulate intracellular Ca2+ homeostasis and signal transduction. Abnormal expression of TRPV1 is closely related to malignant tumors of the female reproductive system such as breast, ovarian, cervical and endometrial cancers. In this study, we found a significant reduction of TRPV1 expression in cervical squamous cell carcinoma and this expression is inversely association with the risk of cervical squamous cell carcinoma. Furthermore, TRPV1 is involved in cell differentiation, iron death, inflammatory response, and metabolic regulation in cervical squamous cell carcinoma. Meanwhile TRPV1 is positively correlated with T cells and negatively associated with macrophages, indicating that TRPV is associated with tumor cell immunity. Therefore, TRPV1 may be a potential marker of cervical cancer and a promising anti-cancer drug candidate.

Sponge-Like Macroporous Hydrogel with Antibacterial and ROS Scavenging Capabilities for Diabetic Wound Regeneration.

Hydrogels with soft and wet properties have been intensively investigated for chronic disease tissue repair. Nevertheless, tissue engineering hydrogels containing high water content are often simultaneously suffered from low porous size and low water-resistant capacities, leading to undesirable surgery outcomes. Here, a novel sponge-like macro-porous hydrogel (SM-hydrogel) with stable macro-porous structures and anti-swelling performances is developed via a facile, fast yet robust approach induced by Ti3 C2 MXene additives. The MXene-induced SM-hydrogels (80% water content) with 200-300 µm open macropores, demonstrating ideal mass/nutrient infiltration capability at ≈20-fold higher water/blood-transport velocity over that of the nonporous hydrogels. Moreover, the highly strong interactions between MXene and polymer chains endow the SM-hydrogels with excellent anti-swelling capability, promising equilibrium SM-hydrogels with identical macro-porous structures and toughened mechanical performances. The SM-hydrogel with versatile functions such as facilitating mass transport, antibacterial (bacterial viability in (Acrylic acid-co-Methacrylamide dopamine) copolymer-Ti3 C2 MXene below 25%), and reactive oxygen species scavenging capacities (96% scavenging ratio at 120 min) synergistically promotes diabetic wound healing (compared with non-porous hydrogels the wound closure rate increased from 39% to 81% within 7 days). Therefore, the durable SM-hydrogels exhibit connective macro-porous structures and bears versatile functions induced by MXene, demonstrating its great potential for wound tissue engineering.

PgC3Mg metal-organic cages functionalized hydrogels with enhanced bioactive and ROS scavenging capabilities for accelerated bone regeneration.

The repair of large bone defects is an urgent problem in the clinic. Note that the disruption of redox homeostasis around bone defect sites might hinder the new bone reconstruction. The rational design of hydrogels for bone regeneration still faces the challenges of insufficient antioxidant capability and weak osteogenesis performance. Here, motivated by the versatile therapeutic functions of metal-organic cages, magnesium-seamed C-propylpyrogallol[4]arene (PgC3Mg) functionalized biodegradable and porous gelatin methacrylate (GelMA) hydrogels are constructed. The novel metal-organic cages endow hydrogels with highly bioactive characteristics and strong reactive oxygen species (ROS)-scavenging ability owing to the simultaneous release of bioactive Mg2+ ions and antioxidant phenolic hydroxyl-rich moieties. The in vitro results reveal that the PgC3Mg modified biocompatible hydrogels show higher expression of osteo-related genes and significantly eliminate the intracellular ROS levels of bone marrow-derived mesenchymal stem cells (BMSCs) against oxidative damage. Meanwhile, the bioactive and ROS scavenging hydrogels can accelerate bone regeneration in large cranial defects. Overall, this study may provide new insights into the designing of regenerative bone grafts with simultaneously enhanced osteogenic and antioxidant capabilities.

Combined [18F]FDG-PET with MRI structural patterns in predicting post-surgical seizure outcomes in temporal lobe epilepsy patients.

OBJECTIVES: To integrate the glucose metabolism measured using [18F]FDG PET/CT and anatomical features measured using MRI to forecast the post-surgical seizure outcomes of intractable temporal lobe epilepsy. METHODS: This retrospective study enrolled 63 patients with drug-resistant temporal lobe epilepsy. Z-transform of the patients' PET images based on comparison with a database of healthy controls, cortical thickness, and quantitative anisotropy (QA) of the diffusion spectrum imaging concordant/non-concordant with cortical resection was adopted to quantify their predictive values for the post-surgical seizure outcomes. RESULTS: The PET hypometabolism region was concordant with the surgical field in 47 of the 63 patients. Forty-two patients were seizure-free post-surgery. The sensitivity and specificity of PET in predicting seizure freedom were 89.4% and 68.8%, respectively. Complete resection of foci with overlapped PET, cortical thickness, and QA abnormalities resulted in Engel I in 27 patients, which was a good predictor of seizure freedom with an odds ratio (OR) of 19.57 (95% CI 2.38-161.25, p = 0.006). Hypometabolism involved in multiple lobes (OR = 7.18, 95% CI 1.02-50.75, p = 0.048) and foci of hypometabolism with QA/cortical thickness abnormalities outside surgical field (OR = 14.72, 95% CI 2.13-101.56, p = 0.006) were two major predictors of Engel III/IV outcomes. ORs of QA to predict Engel I and seizure recurrence were 14.64 (95% CI 2.90-73.80, p = 0.001) and 12.01 (95% CI 2.91-49.65, p = 0.001), respectively. CONCLUSION: Combined PET and structural pattern is helpful to predict the post-surgical seizure outcomes and worse outcomes of Engel III/IV. This might decrease unnecessary surgical injuries to patients who are potentially not amenable to surgery. KEY POINTS: • A combined metabolic and structural pattern is helpful to predict the post-surgical seizure outcomes. • Favorable post-surgical seizure outcome was most likely reached in patients whose hypometabolism overlapped with the structural changes. • Hypometabolism in multiple lobes and QA or cortical thickness abnormalities outside the surgical field were predictors of worse seizure outcomes of Engel III/IV.

Breathable, Moisturizing, Anti-Oxidation SSD-PG-PVA/KGM Fibrous Membranes for Accelerating Diabetic Wound Tissue Regeneration.

Diabetic wound tissue repair and regeneration is a multi-step process that includes cell proliferation and migration, gas and moisture management, and inflammatory responses. However, current wound dressing designs lack consideration of the wound microenvironment of diabetic patients, making diabetic wound tissue repair a challenge. Here, we report a wound dressing (SSD-PG-PVA/KGM) with a porous structure and anti-oxidant properties for promoting diabetic wound tissue repair. First, the porous structure created by electrospinning technology encourages cell proliferation and migration in the wound while also providing breathability and moisture retention. Second, adding natural polyphenols (PG) and saikosaponins (SSDs) to the wound reduced reactive oxygen species levels and oxide stress. In vitro cell experiments showed that SSD-PG-PVA/KGM had good biocompatibility. Due to the biocompatibility, anti-oxidation ability, breathability, and moisturizing, SSD-PG-PVA/KGM could effectively promote the repair of diabetic wound tissue (the wound closure rate was 95.6% at 14 days).

Graphene Oxide-Coated Metal-Insulator-Metal SERS Substrates for Trace Melamine Detection.

Surface-enhanced Raman spectroscopy (SERS) has long been an ultrasensitive technique for trace molecule detection. However, the development of a sensitive, stable, and reproducible SERS substrate is still a challenge for practical applications. Here, we demonstrate a cost-effective, centimeter-sized, and highly reproducible SERS substrate using the nanosphere lithography technique. It consists of a hexagonally packed Ag metasurface on a SiO2/Au/Si substrate. A seconds-lasting etching process of a self-assembled nanosphere mask manipulates the geometry of the deposited Ag metasurface on the SiO2/Au/Si substrate, which attains the wavelength matching between the optical absorbance of the Ag/SiO2/Au/Si substrate and the excitation laser wavelength as well as the enhancement of Raman signals. By spin-coating a thin layer of graphene oxide on the substrate, a SERS performance with 1.1 × 105 analytical enhancement factor and a limit of detection of 10-9 M for melamine is achieved. Experimental results reveal that our proposed strategy could provide a promising platform for SERS-based rapid trace detection in food safety control and environmental monitoring.

Diffusion spectrum imaging predicts hippocampal sclerosis in mesial temporal lobe epilepsy patients.

OBJECTIVES: Epileptic patients suffer from seizure recurrence after surgery due to the challenging localization. Improvement of the noninvasive imaging-based approach for a better definition of the abnormalities would be helpful for a better outcome. METHODS: The quantitative anisotropy (QA) of diffusion spectrum imaging (DSI) is a quantitative scalar of evaluating the water diffusivity. Herein, we investigated the association between neuronal diameters or density acquired in literature and QA of DSI as well as the seizure localization in temporal lobe epilepsy. Thirty healthy controls (HCs) and 30 patients with hippocampal sclerosis (HS) were retrospectively analyzed. QA values were calculated and interactively compared between the areas with different neuronal diameter/density acquired from literature in the HCP-1021 template. Diagnostic tests were performed on Z-transformed asymmetry indices (AIs) of QA (which exclude physical asymmetry) among HS patients to evaluate its clinical value. RESULTS: The QA values in HCs conformed with different pyramidal cell distributions ranged from giant to small; corresponding groups were the motor-sensory, associative, and limbic groups, respectively. Additionally, the QA value was correlated with the neuronal diameter/density in cortical layer IIIc (correlation coefficient with diameter: 0.529, p = 0.035; density: -0.678, p = 0.011). Decreases in cingulum hippocampal segments (Chs) were consistently observed on the sclerosed side in patients. The area under the curve of the Z-transformed AI in Chs to the lateralization of HS was 0.957 (sensitivity: 0.909, specificity: 0.895). INTERPRETATION: QA based on DSI is likely to be useful to provide information to reflect the neuronal diameter/density and further facilitate localization of epileptic tissues.

Photoelastic plasmonic metasurfaces with ultra-large near infrared spectral tuning.

Metasurfaces, consisting of artificially fabricated sub-wavelength meta-atoms with pre-designable electromagnetic properties, provide novel opportunities to a variety of applications such as light detectors/sensors, local field imaging and optical displays. Currently, the tuning of most metasurfaces requires redesigning and reproducing the entire structure, rendering them ineligible for post-fabrication shape-morphing or spectral reconfigurability. Here, we report a photoelastic metasurface with an all-optical and reversible resonance tuning in the near infrared range. The photoelastic metasurface consists of hexagonal gold nanoarrays deposited on a deformable substrate made of a liquid crystalline network. Upon photo-actuation, the substrate deforms, causing the lattice to change and, as a result, the plasmon resonance to shift. The centre wavelength of the plasmon resonance exhibits an ultra-large spectral tuning of over 245 nm, from 1490 to 1245 nm, while the anisotropic deformability also endows light-switchable sensitivity in probing polarization. The proposed concept establishes a light-controlled soft platform that is of great potential for tunable/reconfigurable photonic devices, such as nano-filters, -couplers, -holograms, and displays with structural colors.