Self-adaptive pyroptosis-responsive nanoliposomes block pyroptosis in autoimmune inflammatory diseases.

Nanoliposomes have a broad range of applications in the treatment of autoimmune inflammatory diseases because of their ability to considerably enhance drug transport. For their clinical application, nanoliposomes must be able to realize on-demand release of drugs at disease sites to maximize drug-delivery efficacy and minimize side effects. Therefore, responsive drug-release strategies for inflammation treatment have been explored; however, no specific design has been realized for a responsive drug-delivery system based on pyroptosis-related inflammation. Herein, we report a pioneering strategy for self-adaptive pyroptosis-responsive liposomes (R8-cardiolipin-containing nanoliposomes encapsulating dimethyl fumarate, RC-NL@DMF) that precisely release encapsulated anti-pyroptotic drugs into pyroptotic cells. The activated key pyroptotic protein, the N-terminal domain of gasdermin E, selectively integrates with the cardiolipin of liposomes, thus forming pores for controlled drug release, pyroptosis, and inflammation inhibition. Therefore, RC-NL@DMF exhibited effective therapeutic efficacies to alleviate autoimmune inflammatory damages in zymosan-induced arthritis mice and dextran sulfate sodium-induced inflammatory bowel disease mice. Our novel approach holds great promise for self-adaptive pyroptosis-responsive on-demand drug delivery, suppressing pyroptosis and treating autoimmune inflammatory diseases.

Silk fibroin hydrogel adhesive enables sealed-tight reconstruction of meniscus tears.

Despite orientationally variant tears of the meniscus, suture repair is the current clinical gold treatment. However, inaccessible tears in company with re-tears susceptibility remain unresolved. To extend meniscal repair tools from the perspective of adhesion and regeneration, we design a dual functional biologic-released bioadhesive (S-PIL10) comprised of methacrylated silk fibroin crosslinked with phenylboronic acid-ionic liquid loading with growth factor TGF-ß1, which integrates chemo-mechanical restoration with inner meniscal regeneration. Supramolecular interactions of ß-sheets and hydrogen bonds richened by phenylboronic acid-ionic liquid (PIL) result in enhanced wet adhesion, swelling resistance, and anti-fatigue capabilities, compared to neat silk fibroin gel. Besides, elimination of reactive oxygen species (ROS) by S-PIL10 further fortifies localized meniscus tear repair by affecting inflammatory microenvironment with dynamic borate ester bonds, and S-PIL10 continuously releases TGF-ß1 for cell recruitment and bridging of defect edge. In vivo rabbit models functionally evidence the seamless and dense reconstruction of torn meniscus, verifying that the concept of meniscus adhesive is feasible and providing a promising revolutionary strategy for preclinical research to repair meniscus tears.

Advances in Hydrogels for Meniscus Tissue Engineering: A Focus on Biomaterials, Crosslinking, Therapeutic Additives.

Meniscus tissue engineering (MTE) has emerged as a promising strategy for meniscus repair and regeneration. As versatile platforms, hydrogels have gained significant attention in this field, as they possess tunable properties that allow them to mimic native extracellular matrices and provide a suitable microenvironment. Additionally, hydrogels can be minimally invasively injected and can be adjusted to match the shape of the implant site. They can conveniently and effectively deliver bioactive additives and demonstrate good compatibility with other functional materials. These inherent qualities have made hydrogel a promising candidate for therapeutic approaches in meniscus repair and regeneration. This article provides a comprehensive review of the advancements made in the research on hydrogel application for meniscus tissue engineering. Firstly, the biomaterials and crosslinking strategies used in the formation of hydrogels are summarized and analyzed. Subsequently, the role of therapeutic additives, including cells, growth factors, and other active products, in facilitating meniscus repair and regeneration is thoroughly discussed. Furthermore, we summarize the key issues for designing hydrogels used in MTE. Finally, we conclude with the current challenges encountered by hydrogel applications and suggest potential solutions for addressing these challenges in the field of MTE. We hope this review provides a resource for researchers and practitioners interested in this field, thereby facilitating the exploration of new design possibilities.

Comparison of the ability of exosomes and ectosomes derived from adipose-derived stromal cells to promote cartilage regeneration in a rat osteochondral defect model.

BACKGROUND: Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) offer promising prospects for stimulating cartilage regeneration. The different formation mechanisms suggest that exosomes and ectosomes possess different biological functions. However, little attention has been paid to the differential effects of EV subsets on cartilage regeneration. METHODS: Our study compared the effects of the two EVs isolated from adipose-derived MSCs (ASCs) on chondrocytes and bone marrow-derived MSCs (BMSCs) in vitro. Additionally, we loaded the two EVs into type I collagen hydrogels to optimize their application for the treatment of osteochondral defects in vivo. RESULTS: In vitro experiments demonstrate that ASC-derived exosomes (ASC-Exos) significantly promoted the proliferation and migration of both cells more effectively than ASC-derived ectosomes (ASC-Ectos). Furthermore, ASC-Exos facilitated a stronger differentiation of BMSCs into chondrogenic cells than ASC-Ectos, but both inhibited chondrocyte apoptosis to a similar extent. In the osteochondral defect model of rats, ASC-Exos promoted cartilage regeneration in situ better than ASC-Ectos. At 8 weeks, the hydrogel containing exosomes group (Gel + Exo group) had higher macroscopic and histological scores, a higher value of trabecular bone volume fraction (BV/TV), a lower value of trabecular thickness (Tb.Sp), and a better remodeling of extracellular matrix than the hydrogel containing ectosomes group (Gel + Ecto group). At 4 and 8 weeks, the expression of CD206 and Arginase-1 in the Gel + Exo group was significantly higher than that in the Gel + Ecto group. CONCLUSION: Our findings indicate that administering ASC-Exos may be a more effective EV strategy for cartilage regeneration than the administration of ASC-Ectos.

Comparative Effects of Exosomes and Ectosomes Isolated From Adipose-Derived Mesenchymal Stem Cells on Achilles Tendinopathy in a Rat Model.

BACKGROUND: Extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have gained momentum as a treatment for tendinopathy. Multiple studies have demonstrated significant differences in cargo composition between the 2 subtypes of MSC-EVs (ie, exosomes and ectosomes), which may result in different therapeutic effects. However, the effects of the 2 EV subtypes on tendinopathy have not yet been compared. PURPOSE: To compare the effects of adipose stem cell-derived exosomes (ASC-Exos) and ectosomes (ASC-Ectos) on Achilles tendinopathy. STUDY DESIGN: Controlled laboratory study. METHODS: Rats were administered collagenase injections to generate a model of Achilles tendinopathy. A week later, 36 rats were randomly assigned to 3 groups. In each group, Achilles tendons were injected with equal volumes of ASC-Exos, ASC-Ectos, or saline (12 legs/group). The healing outcomes were evaluated by magnetic resonance imaging, histology, immunohistochemistry, transmission electron microscopy, and biomechanical testing at 3 and 5 weeks after collagenase injection. RESULTS: At 3 and 5 weeks, the ASC-Exo group had better histological scores (P = .0036 and P = .0276, respectively), a lower fibril density (P < .0001 and P = .0310, respectively), and a larger collagen diameter (P = .0052 and P < .0001, respectively) than the ASC-Ecto group. At 5 weeks, the expression of collagen type 1 and CD206 in the ASC-Exo group was significantly higher than that in the ASC-Ecto group (P = .0025 and P = .0010, respectively). Regarding biomechanical testing, the ASC-Exo group showed higher failure load (P = .0005), tensile stress (P < .0001), and elastic modulus (P < .0001) than the ASC-Ecto group. CONCLUSION: ASC-Exos had more beneficial effects on tendon repair than ASC-Ectos in a rat model of Achilles tendinopathy. CLINICAL RELEVANCE: Administration of ASC-EVs may have the potential to treat Achilles tendinopathy, and delivery of ASC-Exos could provide additional benefits. It is necessary to compare the healing responses caused by different EV subtypes to further understand their effects on tendinopathy and to aid clinical decision making.

Short- to Midterm Clinical and Radiological Outcomes After Matrix-Associated Autologous Chondrocyte Implantation for Chondral Defects in Knees.

BACKGROUND: Matrix-associated autologous chondrocyte implantation (MACI) has been proven to provide favorable short-term results for chondral defects in knees. However, it remains unclear whether the clinical benefits of MACI persist in the longer term. PURPOSE: The purpose of this prospective study was to evaluate the clinical and radiological outcomes, at short- and midterm follow-up, for patients undergoing MACI for focal chondral defects of the knee. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 30 consecutive patients (31 knees) were treated using MACI between October 2010 and March 2018. There were 24 male patients and 6 female patients with an average age of 26 years (range, 12-48 years). The areas of the cartilage defect were consistently >2 cm2. All patients underwent MACI for a focal chondral defect of the femoral condyles or trochlea in the knee. These patients had been evaluated for up to 5 years, with an average follow-up of 44 months (range, 6-60 months) postoperatively.The International Knee Documentation Committee (IKDC) score, Lysholm score, and magnetic resonance imaging (MRI) with T2 mapping were used to assess the outcomes. RESULTS: No patients were lost to follow-up. Mean IKDC scores improved from 58.6 (range, 40.2-80.5) to 79.1 (range, 39.1-94.3) at 12 months and up to 88.4 (range, 83.9-100) at 5 years; mean Lysholm scores improved from 67.3 (range, 46-95) to 90.6 (range, 71-100) at 12 months and up to 95.9 (range, 85-100) at 5 years. The MRI with T2 mapping value of the transplanted area was evaluated for 21 knees, which revealed no differences compared with the normal area at 12 months postoperatively. CONCLUSION: From the first year onward, the clinical outcome scores and MRI with T2 mapping values showed continuous and marked improvement, suggesting that MACI is a valid option for localized cartilage defects in the knee.

Application of Plasma-Printed Paper-Based SERS Substrate for Cocaine Detection.

Surface-enhanced Raman spectroscopy (SERS) technology is an attractive method for the prompt and accurate on-site screening of illicit drugs. As portable Raman systems are available for on-site screening, the readiness of SERS technology for sensing applications is predominantly dependent on the accuracy, stability and cost-effectiveness of the SERS strip. An atmospheric-pressure plasma-assisted chemical deposition process that can deposit an even distribution of nanogold particles in a one-step process has been developed. The process was used to print a nanogold film on a paper-based substrate using a HAuCl4 solution precursor. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that the gold has been fully reduced and that subsequent plasma post-treatment decreases the carbon content of the film. Results for cocaine detection using this substrate were compared with two commercial SERS substrates, one based on nanogold on paper and the currently available best commercial SERS substrate based on an Ag pillar structure. A larger number of bands associated with cocaine was detected using the plasma-printed substrate than the commercial substrates across a range of cocaine concentrations from 1 to 5000 ng/mL. A detection limit as low as 1 ng/mL cocaine with high spatial uniformity was demonstrated with the plasma-printed substrate. It is shown that the plasma-printed substrate can be produced at a much lower cost than the price of the commercial substrate.

Risk Factors Analysis of Thoracic Trauma Complicated With Acute Respiratory Distress Syndrome and Observation of Curative Effect of Lung-Protective Ventilation.

PURPOSE: To explore the risk factors of acute respiratory distress syndrome (ARDS) secondary to thoracic trauma and the therapeutic effect of protective lung ventilation in patients with acute respiratory distress syndrome complicated with thoracic trauma. METHODS: We collected 206 patients with thoracic trauma admitted to our hospital from September 2017 to March 2021, counted the incidence of ARDS and analyzed the risk factors of ARDS. To observe the clinical efficacy of the application of lung-protective ventilation therapy in patients with thoracic trauma combined with ARDS. RESULTS: Among 206 patients with thoracic trauma, there were 82 cases of combined ARDS, and its incidence was 39.81%. The 82 patients with ARDS were randomly divided into the control group and the observation group with 42 cases each, and different ventilation methods were used for treatment. The results showed that the mechanical ventilation time (MVT) was shorter in the observation group than in the control group, and the incidence of ventilator-associated lung injury (VALI) and case fatality rate (CFR) were lower than those in the control group (P < 0.05). Arterial partial pressure of oxygen (Pa02), arterial blood carbon dioxide partial pressure (PaCO2), and Oxygenation index (arterial partial pressure of oxygen/Fraction of inspiration O2, PaO2/FiO2) were significantly improved better in both groups after treatment; compared with the control group, patients in the observation group had higher Pa02 levels and lower PaCO2 levels at 8 h and 24 h after ventilation (P < 0.05). Multivariate analysis revealed that blunt trauma, massive blood transfusion, procalcitonin (PCT) level, tumor necrosis factor-α (TNF-α) level, and acute physiology and chronic health score (APACHE II) were all risk factors for Thoracic trauma with ARDS. CONCLUSION: Risk factors for the development of ARDS after thoracic trauma are blunt injuries, massive blood transfusion, high PCT and TNF-α levels, and high APACHE II scores, which can be given active interventions in the early stage of clinical practice to improve patient prognosis. The use of protective lung ventilation therapy can improve the clinical outcome of patients with thoracic trauma combined with ARDS, which is important for improving the ventilation effect and respiratory function of patients.

Combined effects of jarosite and visible light on chalcopyrite dissolution mediated by Acidithiobacillus ferrooxidans.

Although jarosite and visible light are important factors for the formation of acid mine drainage (AMD), the effects of combined jarosite and visible light on chalcopyrite biodissolution have not been explored until now. In order to fill this knowledge gap, the combined effects of jarosite and visible light on chalcopyrite dissolution mediated by Acidithiobacillus ferrooxidans were investigated. The results indicated that jarosite and visible light could significantly accelerate chalcopyrite biodissolution, thus releasing more copper ions, iron ions and producing more acid. This in turn suggests enhanced generation of AMD under these conditions. Biodissolution results, mineral surface morphology, mineralogical phase and elemental composition analyses revealed that the promotion of chalcopyrite dissolution by additional jarosite and visible light was mainly attributed to the acceleration of ferric iron/ferrous iron cycling and the inhibition of the formation of a passivation layer (jarosite and Sn2-/S0) on the surface of chalcopyrite. This study provides a better understanding of the effects of jarosite and visible light on chalcopyrite biodissolution. In the future, the influences of jarosite and visible light on chalcopyrite dissolution should be considered in AMD evaluation to ensure reliability.

Autologous Micro-Fragmented Adipose Tissue as Stem Cell-Based Natural Scaffold for Cartilage Defect Repair.

Osteoarthritis (OA) poses a tough challenge worldwide. Adipose-derived stem cells (ASCs) have been proved to play a promising role in cartilage repair. However, enzymatic digestion, ex vivo culture and expansion, with significant senescence and decline in multipotency, limit their application. The present study was designed to obtain micro-fragmented adipose tissue (MFAT) through gentle mechanical force and determine the effect of this stem cell-based natural scaffold on repair of full-thickness cartilage defects. In this study, ASCs sprouted from MFAT were characterized by multi-differentiation induction and flow cytometry. Scratch and transwell migration assays were operated to determine whether MFAT could promote migration of chondrocytes in vitro. In a rat model, cartilage defects were created on the femoral groove and treated with intra-articular injection of MFAT or PBS for 6 weeks and 12 weeks (n = 12). At the time points, the degree of cartilage repair was evaluated by histological staining, immunohistochemistry and scoring, respectively. Two unoperated age-matched animals served as native controls. ASCs derived from MFAT possessed properties to differentiate into adipocytes, osteocytes and chondrocytes, with expression of mesenchymal stem cell markers (CD29, 44, 90) and no expression of hematopoietic markers (CD31, 34, 45). In addition, MFAT could significantly promote migration of chondrocytes. MFAT-treated defects showed improved macroscopic appearance and histological evaluation compared with PBS-treated defects at both time points. After 12 weeks of treatment, MFAT-treated defects displayed regular surface, high amount of hyaline cartilage, intact subchondral bone reconstruction and corresponding formation of type I, II, and VI collagen, which resembled the normal cartilage. This study demonstrates the efficacy of MFAT on cartilage repair in an animal model for the first time, and the utility of MFAT as a ready-to-use therapeutic alternative to traditional stem cell therapy.

Lesions of the Long Head of the Biceps Tendon Concomitant with Rotator Cuff Tears: Tenotomy or Subpectoral Mini-open Tenodesis? A Comparative Short to Mid-term Follow-up Study.

OBJECTIVE: To compare the clinical and radiological outcomes of patients who underwent rotator cuff repair (RCR) concomitant with long head of the biceps tendon (LHBT) tenotomy or subpectoral mini-open tenodesis. METHODS: Prospectively collected data was reviewed on 154 patients, who underwent a LHBT procedure (tenotomy or tenodesis) concomitant with RCR between January 2010 and January 2017. The exclusion criteria were irreparable massive rotator cuff tear, rotator cuff partial tear, subscapular tendon tear, glenohumeral arthritis, and prior shoulder surgery. The two patient groups are as follows: RCR + Tenotomy (Group A) and RCR + Subpectoral mini-open tenodesis (Group B). The visual analog scale (VAS) for pain, Constant Score scale, American Shoulder and Elbow Surgeons (ASES) scores, and the Disabilities of the Arm, Shoulder and Hand (DASH) scores preoperatively and 1 month, 3 months, 6 months, 1 year postoperatively and the latest out-patient clinic were compared between the two groups. RESULTS: Ninety-two patients in Group A and 62 patients in Group B completed the follow-up, with a median follow-up time of 27 and 42 months respectively. At the final follow-up, the VAS, Constant, ASES, and DASH scores in Group A were 0.1 ± 0.2, 87.0 ± 12.8, 96.4 ± 4.3 and 6.6 ± 4.8 respectively, and the VAS, Constant, ASES, and DASH scores in Group B were 0.1 ± 0.3, 92.5 ± 3.9, 96.3 ± 3.6 and 2.9 ± 1.3 respectively. Clinical evaluation scales showed satisfactory results in both groups, and there were no statistically significant differences between the two groups at the same follow-up time. Popeye sign was detected in one case of Group A (1.1%) and in one case of Group B (1.6%, P > 0.05). CONCLUSION: Both tenotomy and subpectoral mini-open tenodesis are effective for concomitant lesions of the LHBT in patients with reparable rotator cuff tears, and subpectoral mini-open tenodesis of the LHBT does not provide any significant clinical or functional improvement than isolated tenotomy.

Role of infrapatellar fat pad in pathological process of knee osteoarthritis: Future applications in treatment.

It has been found that obese people have a higher proportion in suffering from osteoarthritis (OA), not only in the weight-bearing joints like knee and hip joints, even in non-weight-bearing joints such as hand joints. One of the reasons is because the large amount of adipose tissue secretes some factors, which can promote the occurrence of arthritis. As an important structure of the knee joint, the infrapatellar fat pad (IPFP) is actually a piece of adipose tissue. The aim of this review is to offer a comprehensive view of the anatomy and physiological characteristics of IPFP and its relationship with the pathological process of OA, indicating the important function of IPFP in OA. At the same time, with the development of adipose derived stem cells in the treatment of OA, owing to its special advantages, the IPFP is becoming a kind of important, minimally invasive fat stem cell source, providing a new approach for the treatment of OA. We hope that this review will offer an overview of all published data regarding the IPFP and will indicate novel directions for future research.

Ochronotic arthritis and ochronotic Achilles tendon rupture in alkaptonuria: A 6 years follow-up case report in China.

INTRODUCTION: Alkaptonuria (AKU) is a rare disease caused by deficiency of homogentisate 1,2-dioxygenase which results in deposition of homogentisic acid (HGA). Ochronotic arthritis, the deposition of excess oxidized HGA in the connective tissues, causes pigmentation and degeneration of the joint tissues ultimately resulting in chronic inflammation and osteoarthritis. The ochronotic arthritis has similar clinical features with osteoarthritis. There is currently no specific treatment for AKU and management is usually symptomatic. In severe cases, total joint arthroplasty is the major treatment approaches. It is rarely reported in China. PATIENT CONCERNS: Here we reported a case of a patient with bilateral knee pain for more than 1 year. He complained of a 20-year history of chronic, nonspecific low back pain and stiffness. His urine was black since he was a child. Six years after the knee surgery, his Achilles tendon ruptured. DIAGNOSIS: Specific radiographic and magnetic resonance imaging manifestations were observed. Darkly pigmented full-thickness cartilage and subchondral bone were found during the operation. Histological investigation also manifested dark stains in meniscus and synovial tissues. Black-denatured tendon tissue was also found during the operation. The patient was diagnosed as AKU. INTERVENTIONS: Total knee arthroplasty and Achilles tendon repair were operated separately after the disease was diagnosed. OUTCOMES: The patient recovered very well after the second surgery. He returned to full activities, described no knee pain, and presented to the clinic walking without any aid. Physical examination revealed 0 to 20 of plantar flexion and 0 to 15 of dorsiflexion of the ankle. CONCLUSIONS: Ochronosis is a very rare disease in Asia. This paper supplies new information for study of this disease. The mechanism is still unknown right now. Further studies will be necessary.

In vitro Chondrocyte Responses in Mg-doped Wollastonite/Hydrogel Composite Scaffolds for Osteochondral Interface Regeneration.

The zone of calcified cartilage (ZCC) is the mineralized region between the hyaline cartilage and subchondral bone and is critical in cartilage repair. A new non-stoichiometric calcium silicate (10% Ca substituted by Mg; CSi-Mg10) has been demonstrated to be highly bioactive in an osteogenic environment in vivo. This study is aimed to systematically evaluate the potential to regenerate osteochondral interface with different amount of Ca-Mg silicate in hydrogel-based scaffolds, and to compare with the scaffolds containing conventional Ca-phosphate biomaterials. Hydrogel-based porous scaffolds combined with 0-6% CSi-Mg10, 6% ß-tricalcium phosphate (ß-TCP) or 6% nanohydroxyapatite (nHAp) were made with three-dimensional (3D) printing. An increase in CSi-Mg10 content is desirable for promoting the hypertrophy and mineralization of chondrocytes, as well as cell proliferation and matrix deposition. Osteogenic and chondrogenic induction were both up-regulated in a dose-dependent manner. In comparison with the scaffolds containing 6% ß-TCP or nHAp, human deep zone chondrocytes (hDZCs) seeded on CSi-Mg10 scaffold of equivalent concentration exhibited higher mineralization. It is noteworthy that the hDZCs in the 6% CSi-Mg10 scaffolds maintained a higher expression of the calcified cartilage zone specific extracellular matrix marker and hypertrophic marker, collagen type X. Immunohistochemical and Alizarin Red staining reconfirmed these findings. The study demonstrated that hydrogel-based hybrid scaffolds containing 6% CSi-Mg10 are particularly desirable for inducing the formation of calcified cartilage.

How does the inclination of the tibial component matter? A three-dimensional finite element analysis of medial mobile-bearing unicompartmental arthroplasty.

BACKGROUND: Medial unicompartmental knee arthroplasty (UKA) using Oxford mobile-bearing prosthesis is performed in the treatment of medial compartmental arthritis of the knee. However, little is known about the stress distributions for mobile-bearing UKA on the medial tibial plateau. METHODS: In this study, the stresses on the coronal plane were calculated in a three-dimensional model of the proximal tibia. The features of the stress distribution were investigated when the tibial tray was placed in 15°, 10°, six degrees, and three degrees varus, neutral (0°), and in three degrees, six degrees, 10°, and 15° valgus on the coronal plane of the medial plateau. RESULTS: The peak von Mises stress was found on the cortex below the medial plateau while the stresses of cortical bone increased gradually as the inclination of the tibial tray was changed from varus to valgus. The amount of peak stress was almost the same as that in the normal knee model when the tibial tray was placed in six degrees valgus and consistently lower in varus inclination than in the normal knee model. Conversely, the peak stress of soft bone was found at the bottom of the slot. CONCLUSIONS: This study demonstrates that the inclination of the tibial component affects stress distribution in the proximal tibia after UKA. Slight varus inclination of the mobile-bearing tibial component is acceptable as it lowers the peak stress on the medial cortex. Additionally, placing the tibial tray in slight varus avoids a rise in stress between the tip of the keel and the medial tibial cortex.

Hierarchical Multicomponent Inorganic Metamaterials: Intrinsically Driven Self-Assembly at the Nanoscale.

Increasingly intricate in their composition and structural organization, hierarchical multicomponent metamaterials with nonlinear spatially reconfigurable functionalities challenge the intrinsic constraints of natural materials, revealing tremendous potential for the advancement of biochemistry, nanophotonics, and medicine. Recent breakthroughs in high-resolution nanofabrication utilizing ultranarrow, precisely controlled ion or laser beams have enabled assembly of architectures of unprecedented structural and functional complexity, yet costly, time- and energy-consuming high-resolution sequential techniques do not operate effectively at industry-required scale. Inspired by the fictional Baron Munchausen's fruitless attempt to pull himself up, it is demonstrated that metamaterials can undergo intrinsically driven self-assembly, metaphorically pulling themselves up into existence. These internal drivers hold a key to unlocking the potential of metamaterials and mapping a new direction for the large-area, cost-efficient self-organized fabrication of practical devices. A systematic exploration of these efforts is presently missing, and the driving forces governing the intrinsically driven self-assembly are yet to be fully understood. Here, recent progress in the self-organized formation and self-propelled growth of complex hierarchical multicomponent metamaterials is reviewed, with emphasis on key principles, salient features, and potential limitations of this family of approaches. Special stress is placed on self-assembly driven by plasma, current in liquid, ultrasonic, and similar highly energetic effects, which enable self-directed formation of metamaterials with unique properties and structures.

Single-step ambient-air synthesis of graphene from renewable precursors as electrochemical genosensor.

Thermal chemical vapour deposition techniques for graphene fabrication, while promising, are thus far limited by resource-consuming and energy-intensive principles. In particular, purified gases and extensive vacuum processing are necessary for creating a highly controlled environment, isolated from ambient air, to enable the growth of graphene films. Here we exploit the ambient-air environment to enable the growth of graphene films, without the need for compressed gases. A renewable natural precursor, soybean oil, is transformed into continuous graphene films, composed of single-to-few layers, in a single step. The enabling parameters for controlled synthesis and tailored properties of the graphene film are discussed, and a mechanism for the ambient-air growth is proposed. Furthermore, the functionality of the graphene is demonstrated through direct utilization as an electrode to realize an effective electrochemical genosensor. Our method is applicable to other types of renewable precursors and may open a new avenue for low-cost synthesis of graphene films.

Probing the Interior Crystal Quality in the Development of More Efficient and Smaller Upconversion Nanoparticles.

Optical biomedical imaging using luminescent nanoparticles as contrast agents prefers small size, as they can be used at high dosages and efficiently cleared from body. Reducing nanoparticle size is critical for the stability and specificity for the fluorescence nanoparticles probes for in vitro diagnostics and subcellular imaging. The development of smaller and brighter upconversion nanoparticles (UCNPs) is accordingly a goal for complex imaging in bioenvironments. At present, however, small UCNPs are reported to exhibit less emission intensity due to increased surface deactivation and decreased number of dopants. Here we show that smaller and more efficient UCNPs can be made by improving the interior crystal quality via controlling heating rate during synthesis. We further developed a unique quantitative method for optical characterizations on the single UCNPs with varied sizes and the corresponding shell passivated UCNPs, confirming that the internal crystal quality dominates the relative emission efficiency of the UCNPs.

[Fabrication of bioactive tissue engineering scaffold for reconstructing calcified cartilage layer based on three-dimension printing technique].

OBJECTIVE: To fabricate organic-inorganic composite tissue engineering scaffolds for reconstructing calcified cartilage layer based on three-dimensional (3D) printing technique. METHODS: The scaffolds were developed by 3D-printing technique with highly bioactive calcium-magnesium silicate ultrafine particles of 1%, 3% and 5% of mass fraction, in which the organic phases were composed of type I collagen and sodium hyaluronate. The 3D-printed scaffolds were then crosslinked and solidified by alginate and CaCl2 aerosol. The pore size and distribution of inorganic phase were observed with scanning electron microscope (SEM); the mechanical properties were tested with universal material testing machine, and the porosity of scaffolds was also measured. RESULTS: Pore size was approximately (212.3 ± 34.2) µm with a porosity of (48.3 ± 5.9)%, the compressive modulus of the scaffolds was (7.2 ± 1.2) MPa, which was irrelevant to the percentage changes of calcium-magnesium silicate, the compressive modulus was between that of cartilage and subchondral bone. CONCLUSION: The porous scaffolds for calcified cartilage layer have been successfully fabricated, which would be used for multi-layered composite scaffolds in osteochondral injury.

Versatile method for template-free synthesis of single crystalline metal and metal alloy nanowires.

Metal and metal alloy nanowires have applications ranging from spintronics to drug delivery, but high quality, high density single crystalline materials have been surprisingly difficult to fabricate. Here we report a versatile, template-free, self-assembly method for fabrication of single crystalline metal and metal alloy nanowires (Co, Ni, NiCo, CoFe, and NiFe) by reduction of metal nitride precursors formed in situ by reaction of metal salts with a nitrogen source. Thiol reduction of the metal nitrides to the metallic phase at 550-600 °C results in nanowire growth. In this process, sulfur acts as a uniaxial structure-directing agent, passivating the surface of the growing nanowires and preventing radial growth. The versatility of the method is demonstrated by achieving nanowire growth from gas-phase, solution-phase or a combination of gas- and solution-phase precursors. The fabrication method is suited to large-area CVD on a wide range of solid substrates.