The Strain Effects and Interfacial Defects of Large ZnSe/ZnS Core/Shell Nanocrystals.

The shell growth of large ZnSe/ZnS nanocrystals( is of great importance in the pursuit of pure-blue emitters for display applications, however, suffers from the challenges of spectral blue-shifts and reduced photoluminescence quantum yields. In this work, the ZnS shell growth on different-sized ZnSe cores is investigated. By controlling the reactivity of Zn and S precursors, the ZnS shell growth can be tuned from defect-related strain-released to defect-free strained mode, corresponding to the blue- and red-shifts of resultant nanocrystals respectively. The shape of strain-released ZnSe/ZnS nanocrystals can be kept nearly spherical during the shell growth, while the shape of strained nanocrystals evolutes from spherical into island-like after the critical thickness. Furthermore, the strain between ZnSe core and ZnS shell can convert the band alignment from type-I into type-II core/shell structure, resulting in red-shifts and improved quantum yield. By correlating the strain effects with interfacial defects, a strain-released shell growth model is proposed to obtain large ZnSe/ZnS nanocrystals with isotropic shell morphology.

Preparation of Multistage Pore TS-1 with Enhanced Photocatalytic Activity, Including Process Studies and Artificial Neural Network Modeling for Synergy Assessment.

Antibiotic residues have been found in several aquatic ecosystems as a result of the widespread use of antibiotics in recent years, which poses a major risk to both human health and the environment. At present, photocatalytic degradation is the most effective and environmentally friendly method. Titanium silicon molecular sieve (TS-1) has been widely used as an industrial catalyst, but its photocatalytic application in wastewater treatment is limited due to its small pores and few active sites. In this paper, we report a method for preparing multistage porous TS-1 with a high specific surface area by alkali treatment. In the photocatalytic removal of CIP (ciprofloxacin) antibiotic wastewater experiments, the alkali-treated catalyst showed better performance in terms of interfacial charge transfer efficiency, which was 2.3 times higher than that of TS-1 synthesized by the conventional method, and it was found to maintain better catalytic performance in the actual water source. In addition, this research studied the effects of solution pH, contaminant concentration, and catalyst dosage on CIP degradation, while liquid chromatography-mass spectrometry (LC-MS) was used to identify intermediates in the degradation process and infer possible degradation pathways and the toxicity of CIP, and its degradation product was also analyzed using ECOSAR 2.2 software, and most of the intermediates were found to be nontoxic and nonharmful. Finally, a 3:5:1 artificial neural network model was established based on the experiments, and the relative importance of the influence of experimental conditions on the degradation rate was determined. The above results confirmed the feasibility and applicability of photocatalytic treatment of wastewater containing antibiotics using visible light excitation alkali post-treatment TS-1, which provided technical support and a theoretical basis for the photocatalytic treatment of wastewater containing antibiotics.

An optimization by response surface methodology for the enhanced production of rMBSP from Pichia pastoris and study of its application.

Background: Recombinant myofibril-bound serine proteinase (rMBSP) was successfully expressed in Pichia pastoris GS115 in our laboratory. However, low production of rMBSP in shake flask constraints further exploration of properties.Methods: A 5-L high cell density fermentation was performed and the fermentation medium was optimized. Response surface methodology (RSM) was used to optimize the culture condition through modeling three selected parameter.Results: Under the optimized culture medium (LBSM, 1% yeast powder and 1% peptone) and culture conditions (induction pH 5.5, temperature 29 °C, time 40 h), the yield of rMBSP was 420 mg/L in a 5-L fermenter, which was a 6-fold increase over thar, expressed in flask cultivation. The desired enzyme was purified by two-step, which yielded a 33.7% recovery of a product that had over 85% purity. The activity of purified rMBSP was significantly inhibited by Ca2+, Mg2+, SDS, guanidine hydrochloeide, acetone, isopropanol, chloroform, n-hexane and n-heptane. Enzymatic analysis revealed a Km of 2.89 ± 0.09 µM and a Vmax of 14.20 ± 0.12 nM•min-1 for rMBSP. LC-MS/MS analysis demonstrated the specific cleavage of bovine serum albumin by rMPSP.Conclusion: These findings suggest that rMPSP has potential as a valuable enzyme for protein science research.

Growth in ever-increasing acidity condition enhanced the adaptation and bioleaching ability of Leptospirillum ferriphilum.

Low pH eliminated the jarosite accumulation and improved the interfacial reaction rate during the bioleaching process. However, high acidity tends to make environments less hospitable, even for organisms that live in extreme places, so a great challenge existed for bioleaching at low pH conditions. This study demonstrated that the adaption and bioleaching ability of Leptospirillum ferriphilum could be improved after the long-term adaptive evolution of the community under acidity conditions. It was found that the acidity-adapted strain showed robust ferrous iron oxidation activity in wider pH, high concentration of ferrous iron, and lower temperature. Although the enhancement for heavy metal tolerance was limited, the resistance for MgSO4, Na2SO4, and organic matter was stimulative. More importantly, both pyrite and printed circuit board bioleaching revealed the higher bioleaching ability of the acid-resistant strain. These adaptation and bioleaching details provided an available approach for the improvement of bioleaching techniques.

Multisite Cation Regulation of Broadband Cyan-Emitting (Ba1-xSrx)9Lu2Si6O24/Eu2+ Phosphors for Full-Spectrum wLEDs.

Developing broadband cyan-emitting phosphors is an essential issue to achieve high-quality full-spectrum phosphor-converted white light-emitting diodes. Multisite cation regulation to modify the photoluminescence spectrum is a valid way to achieve broadband emission for phosphors. The Ba9Lu2Si6O24 lattice with various cation sites for activator ions is a preferred host for broadband emitting phosphors. The preferential crystallographic sites of Eu2+ in the Ba9Lu2Si6O24 lattice are identified based on the crystal field theory, crystal structure, and bond indices (such as NAC and SBOs) of the cations. Sr substitution in Ba9Lu2Si6O24/Eu2+ phosphor affects the location of Eu2+ activator ions, which is investigated via the first-principles density functional theory calculations, Rietveld refinement, and luminescence decay curves, and results in the modification of luminescence properties and thermal stability. The Sr-substituted (Ba0.8Sr0.2)9Lu2Si6O24/Eu2+ sample exhibits a broadband emission spectrum peaked at 471 and 518 nm with a large full width half maximum of 139 nm, covering blue-cyan-green regions, which can be an excellent candidate as broadband cyan-emitting phosphors for high-quality full-spectrum wLEDs.

Comparison on the properties of bovine pericardium and porcine pericardium used as leaflet materials of transcatheter heart valve.

BACKGROUND: In order to obtain the smaller delivery diameter, porcine pericardium had been used as a substitute material of bovine pericardium for the leaflet materials of transcatheter heart valve (THV). However, the differences between them had not been fully studied. Therefore, this study compared the microstructure, biochemical and mechanical properties of two materials and hydrodynamics of THV made by the two materials in detail. METHODS: In this study, firstly, the microstructure of pericardium was analyzed by staining and scanning electron microscope; secondly, the biochemical properties of pericardium after different processes were compared by heat shrinkage temperature test, free amino and carboxyl concentration test, enzyme degradation test, subcutaneous implantation calcification analysis in rats; finally, the mechanical properties were evaluated by uniaxial tensile test before and after the pericardium being crimped, and then, the hydrodynamics of THV was studied according to the ISO5840 standard. RESULTS: Compared with bovine pericardium, after the same process, porcine pericardium showed a looser and tinier fiber bundle, a similar free carboxyl concentration, a lower resistance to enzyme degradation, a significantly lower calcification, bearing capacity and damage after being crimped, a better hydrodynamic and adaption with lower cardiac output and deformation of implantation position. Meanwhile the dehydration process of pericardium almost had preserved all the biochemical advantages of two materials. CONCLUSION: In this study, porcine and bovine pericardium showed some significant differences in biochemical, mechanical properties and hydrodynamics. According to the results, it was presumed that the thinner porcine pericardium might be more suitable for THV of right heart system. Meanwhile, more attention should be taken for the calcification of THV made by the bovine pericardium.

Second-Sphere Polyhedron-Distortion-Induced Broadened and Red-Shifted Emission in Lu3(MgxAl2-x)(Al3-xSix)O12:Ce3+ for Warm WLED.

Orange-yellow phosphors with extended broadband emission are highly desirable for warmer white-light-emitting diodes (WLED) with a higher color-rendering index. Targeted phosphors Ce3+-doped Lu3(MgxAl2-x)(Al3-xSix)O12 (x = 0, 0.25, 0.50, 0.75, and 1.00) were developed by chemical composition modification for luminescent tuning from green to orange-yellow with spectral broadening. The correlation between structure evolution and luminescent properties was elucidated by the local structure, fluorescence lifetime, and Eu3+ luminescence as a structural probe. The polyhedron distortion in the second-sphere coordination leads to the site differentiation and symmetry degradation of Ce3+ with the accommodation of (MgSi)6+ pairs, comprehensively resulting in the red shift (540 → 564 nm) and broadening in emission spectra. The WLED fabrication results demonstrate that the red shift and broadening in the emission of Lu3(MgxAl2-x)(Al3-xSix)O12:Ce3+ make it more suitable for the single-phosphor converted warm WLED.

Cyan-Green Phosphor (Lu2M)(Al4Si)O12:Ce3+ for High-Quality LED Lamp: Tunable Photoluminescence Properties and Enhanced Thermal Stability.

High-quality white light-emitting diodes (w-LEDs) are mainly determined by conversion phosphors and the enhancement of cyan component that dominates the high color rendering index. New phosphors (Lu2M)(Al4Si)O12:Ce3+ (M = Mg, Ca, Sr and Ba), showing a cyan-green emission, have been achieved via the co-substitution of Lu3+-Al3+ by M2+-Si4+ pair in Lu3Al5O12:Ce3+ to compensate for the lack of cyan region and avoid using multiple phosphors. The excitation bands of (Lu2M)(Al4Si)O12:Ce3+ (M = Mg, Ca, Sr and Ba) show a red-shift from 434 to 445 nm which is attributed to the larger centroid shift and crystal field splitting. The enhanced structural rigidity associated with the accommodation of larger M2+ leads to a decreasing Stokes shift and the corresponding blue-shift (533 → 511 nm) in emission spectra, along with an improvement in thermal stability (keeping ∼93% at 150 °C). The cyan-green phosphor Lu2BaAl4SiO12:Ce3+ enables to fabricate a superhigh color rendering w-LED ( Ra = 96.6), verifying its superiority and application prospect in high-quality solid-state lightings.

YScSi4N6C:Ce3+-A Broad Cyan-Emitting Phosphor To Weaken the Cyan Cavity in Full-Spectrum White Light-Emitting Diodes.

On the basis of a rough rule of thumb that the difference in ionic radius for the interstitial cationic pair may affect the structure of some nitride and carbonitride compounds, a novel carbonitride phosphor, YScSi4N6C:Ce3+, was successfully designed. The crystal structure (space group P63mc (No. 186), a = b = 5.9109(8) Å, c = 9.67701(9) Å, α = ß = 90°, γ = 120°) was characterized by single-crystal synchrotron X-ray diffraction and further confirmed by powder X-ray diffraction and refined with Rietveld methods. Ce3+-doped YScSi4N6C shows a broad excitation band ranging from 280 to 425 nm and a broad cyan emission band peaking at about 469 nm upon excitation by near-UV light (400 nm). The mechanism of thermal quenching for this phosphor was also investigated. In addition, a white light-emitting diode (w-LED) was prepared by coating a near-UV chip (λem = 405 nm) with YScSi4N6C:Ce3+, ß-sialon:Eu2+ (green), and CaAlSiN3:Eu2+ (red) phosphors. It emitted a well-distributed warm white light with high color rendering index (CRI) of 94.7 and a correlated color temperature (CCT) of 4159 K. The special color rendering index R12 of the obtained white light was as high as 88. All of the results indicate that this novel phosphor can compensate for the cyan cavity and has potential applications in the full-spectrum lighting field.

Synthesis and Photoluminescence Properties of a Blue-Emitting La3Si8N11O4:Eu2+ Phosphor.

Eu2+-doped La3Si8N11O4 phosphors were synthesized by the high temperature solid-state method, and their photoluminescence properties were investigated in this work. La3Si8N11O4:Eu2+ exhibits a strong broad absorption band centered at 320 nm, spanning the spectral range of 300-600 nm due to 4f7 → 4f65d1 electronic transitions of Eu2+. The emission spectra show a broad and asymmetric band peaking at 481-513 nm depending on the Eu2+ concentration, and the emission color can be tuned in a broad range owing to the energy transfer between Eu2+ ions occupying two independent crystallographic sites. Compared to the Ce3+-doped La3Si8N11O4, the Eu2+-doped one shows a larger thermal quenching, predominantly owing to photoionization. Under 320 nm excitation, the internal and external quantum efficiencies are 44 and 33%, respectively.

Paenibacillus ripae sp. nov., isolated from bank side soil.

A Gram-stain-variable, rod-shaped, non-motile and endospore-forming bacterium, designated strain HZ1T, was isolated from a sample of bank side soil from Hangzhou city, Zhejiang province, PR China. On the basis of 16S rRNA gene sequence analysis, strain HZ1T was closely related to members of the genus Paenibacillus, sharing the highest levels of sequence similarity with Paenibacillus agarexedens DSM 1327T (94.4 %), Paenibacillus sputi KIT00200-70066-1T (94.4 %). Growth occurred at 15-42 °C (optimum 30-37 °C), pH 5.0-9.5 (optimum pH 7.0-8.0) and NaCl concentrations of up to 6.0 % (w/v) were tolerated (optimum 0.5 %). The dominant respiratory quinone was MK-7 and the DNA G+C content was 40.1 mol%. The major fatty acids were anteiso-C15 : 0 and iso-C16 : 0. The major polar lipids of strain HZ1T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and several unknown lipids. The diagnostic diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. Based on its phenotypic and chemotaxonomic characteristics and phylogenetic data, strain HZ1T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus ripae sp. nov. (type strain HZ1T = CCTCC AB 2014276T = LMG 28639T) is proposed.

Circ_0007611 modulates the miR-34c-5p/LPAR2 cascade to suppress proliferation and enhance apoptosis of HTR-8/SVneo cells.

INTRODUCTION: The aberrant biological behaviors of trophoblast cells actively take part in the pathogenesis of preeclampsia (PE). Herein, we defined the action of the circular RNA (circRNA) circ_0007611 on trophoblast cell apoptosis and growth to understand its role in PE. METHODS: Expression of circ_0007611, miR-34c-5p and lysophosphatidic acid receptor 2 (LPAR2) mRNA was analyzed by qPCR. LPAR2 protein was determined by western blotting. Cell proliferation was analyzed by EdU assay. We assessed apoptosis through flow cytometry and analysis of caspase3 activity and apoptosis-related marker proteins. The binding of miR-34c-5p and circ_0007611 or LPAR2 was verified by dual-luciferase and pull-down assays. RESULTS: Circ_0007611 and LPAR2 levels were augmented, while miR-34c-5p was diminished in blood samples of PE. Circ_0007611 deficiency repressed cell apoptosis and enhanced the growth of HTR-8/SVneo cells. Circ_0007611 interacted with miR-34c-5p, and miR-34c-5p depletion reversed circ_0007611 deficiency-induced HTR-8/SVneo cell apoptotic inhibition and growth enhancement. MiR-34c-5p targeted LPAR2, and circ_0007611 affected LPAR2 expression via miR-34c-5p competition. Circ_0007611 deficiency-induced HHTR-8/SVneo cell apoptotic inhibition and growth enhancement were also counteracted by LPAR2 overexpression. DISCUSSION: Circ_0007611 modulates the miR-34c-5p/LPAR2 cascade to enhance apoptosis and inhibit proliferation in HTR-8/SVneo cells, thereby contributing to the progression of PE.

Probing Thermal Transport on a Suspended Ti3C2Tx MXene Film via a Photothermally Actuated Resonator.

Two-dimensional (2D) Ti3C2Tx MXene materials show great potential in electrochemical and flexible sensors due to their high electrical conductivity, good chemical stability, and special delaminated structure. However, their thermal properties were rarely studied, which remarkably affect the stability and safety of various devices. Here, we fabricated a suspended MXene drum resonator photothermally driven by a sinusoidally modulated laser, measured the thermal time constant by demodulating the thermomechanical motion, and then calculated the thermal conductivity and thermal diffusivity of the MXene film. Experiments show the thermal conductivity of the film increases from 3.10 to 3.58 W/m·K while the thermal diffusivity from 1.06 × 10-6 to 1.22 × 10-6 m2/s when temperature increases from 300 to 360 K. We also confirm the film thermal conductivity is mainly contributed by phonon transport rather than electron transport. Furthermore, the relationship between the mechanical and thermal properties of the MXene films was disclosed. The thermal conductivity decreases when film strain increases, caused by enhanced phonon scattering and softening of high-frequency phonons. The measurements provide a noninvasive method to analyze the thermal characteristics of suspended MXene films, which can be further extended to the thermal properties of other 2D materials.

The Role of SF1 and SF2 Helicases in Biotechnological Applications.

Helicases, which utilize ATP hydrolysis to separate nucleic acid duplexes, play crucial roles in DNA and RNA replication, repair, recombination, and transcription. Categorized into the major groups superfamily 1 (SF1) and superfamily 2 (SF2), alongside four minor groups, these proteins exhibit a conserved catalytic core indicative of a shared evolutionary origin while displaying functional diversity through interactions with various substrates. This review summarizes the structures, functions and mechanisms of SF1 and SF2 helicases, with an emphasis on conserved ATPase sites and RecA-like domains essential for their enzymatic and nucleic acid binding capabilities. It highlights the unique 1B and 2B domains in SF1 helicases and their impact on enzymatic activity. The DNA unwinding process is detailed, covering substrate recognition, ATP hydrolysis, and conformational changes, while addressing debates over the active form of UvrD helicase and post-unwinding dissociation. More importantly, this review discusses the biotechnological potential of helicases in emerging technologies such as nanopore sequencing, protein sequencing, and isothermal amplification, focusing on their use in pathogen detection, biosensor enhancement, and cancer treatment. As understanding deepens, innovative applications in genome editing, DNA sequencing, and synthetic biology are anticipated.

Protein nanopore-based sensors for public health analyte detection.

High-throughput and label-free protein nanopore-based sensors are extensively used in DNA sequencing, single-protein analysis, molecular sensing and chemical catalysis with single channel recording. These technologies show great potential for identifying various harmful substances linked to public health by addressing the limitations of current portability and the speed of existing techniques. In this review, we provide an overview of the fundamental principles of nanopore sensing, with a focus on chemical modification and genetic engineering strategies aimed at enhancing the detection sensitivity and identification accuracy of protein nanopores. The engineered protein nanopores enable direct sensing, while the introduction of aptamers and substrates enables indirect sensing, translating the physical structure and chemical properties of analytes into readable signals. These scientific discoveries and engineering efforts have provided new prospects for detecting and monitoring trace hazardous substances.

Review Article Imaging Evaluation for the Size of Saccular Intracranial Aneurysm.

BACKGROUND: In addition to evaluate the morphologic characteristics of intracranial aneurysms, the dimension of the aneurysm is an important parameter for selecting treatment strategies, determining follow-up period, and predicting the risk of rupture. High-resolution vessel wall imaging has an increasingly dominant role in measuring aneurysm size and assessing the risk of rupture accurately. The size of saccular intracranial aneurysm may play an important role as a predictor of the rupture risk. With the rapid improvement in radiological techniques, different noninvasive imaging methods have respective characteristics in saccular intracranial aneurysms (sIA) measurement and morphologic description. Although most studies believe that the larger the aneurysm, the higher the risk of rupture, there is still a synergistic effect of multiple factors (such as location, morphology, history of aneurysmal subarachnoid hemorrhage, and even patient factors) to explain the rupture of small aneurysms. METHODS: A literature search was performed of intracranial aneurysm size and risk of rupture. RESULTS: The specificity and sensitivity of different imaging methods for evaluating intracranial aneurysms varied based on sizes. Rupture risk of aneurysms was associated with multiple factors. A comprehensive assessment that considered aneurysm size in conjunction with other relevant factors would be helpful in guiding options of management. CONCLUSIONS: Accurate measurement of the dimension of sIA is an important basis in the selection of appropriate treatment including intravascular intervention or surgical clipping, as well as for determining the follow-up cycles for conservative or postoperative treatment. A uniform definition of sIA size is recommended to facilitate the integration of similar studies and to accomplish rapid and effective screening of cases in sIA treatment.

Enhanced Pressure Response of Edge-Deposited Graphene Nanomechanical Resonators.

Nanomechanical resonators made of suspended graphene exhibit high sensitivity to pressure changes. Nevertheless, the graphene resonator pressure performance is affected owing to the gas permeation problem between the graphene film and the substrate. Therefore, we prepared edge-deposited graphene resonators by focused ion beam (FIB) deposition of SiO2, and their gas leakage velocities and pressure-sensing ability were demonstrated. In this paper, we characterize the pressure-sensing response and gas leakage velocities of graphene membranes using an all-optical actuation system. The gas leakage velocities of graphene resonators with diameters of 10, 20, and 40 µm are reduced by 5.0 × 106, 2.0 × 107, and 8.1 × 107 atoms/s, respectively, which demonstrates that the edge deposition structure can reduce the gas leakage of the resonator. Furthermore, the pressure-sensing performance of three graphene resonators with different diameters was evaluated, and their average pressure sensitivities were calculated to be 3.4, 2.4, and 1.9 kHz/kPa, with the largest full-range hysteresis errors of 0.6, 0.7, and 1.0%, respectively. The temperature stabilities of the three sizes of resonators in the temperature range of 300-400 K are 0.016, 0.015, and 0.016%/K, and the maximum resonance frequency drift over 1 h is 0.0058, 0.0048, and 0.0112%, respectively. This work has great significance for the improvement of gas leakage velocity characterization of graphene membrane and graphene resonant pressure sensor performance optimization.

Iron capture mechanism for harmless recovering platinum group metals from spent automobile catalyst.

Automotive catalysts are the largest consumption source of platinum group metals (PGMs). When it exceeds its useful life, spent automotive catalysts (SACs) are the most important secondary PGMs resource and are classified as hazardous solid waste. Recycling SAC is a promising solution to alleviate the shortage of PGMs resources for projects and reduce environmental pollution. The technology for recovering PGMs by iron-melting collection can obtain Fe-PGMs alloy and harmless glass slag. In this paper, the spontaneous aggregation and growth behaviour of Fe and PGMs in slag at melting temperature were studied, and the settling velocity of Fe-PGMs particles in the slag was calculated to be 6.68 × 10-3 m/s. The effects of melting time, melting temperature and Fe dosage on PGMs recovery were determined, and the optimal conditions were 10 wt% Fe, 1500°C and 40 min. The toxicity test verifies that the slag obtained is a clean slag harmless to the environment. This work explains the mechanism of Fe collection of PGMs and provides a pathway for efficient and harmless recovery of PGMs from SAC.

Lactiplantibacillus plantarum ATCC8014 Alleviates Postmenopausal Hypercholesterolemia in Mice by Remodeling Intestinal Microbiota to Increase Secondary Bile Acid Excretion.

Hypercholesterolemia poses a significant cardiovascular risk, particularly in postmenopausal women. The anti-hypercholesterolemic properties of Lactiplantibacillus plantarum ATCC8014 (LP) are well recognized; however, its improving symptoms on postmenopausal hypercholesterolemia and the possible mechanisms have yet to be elucidated. Here, we utilized female ApoE-deficient (ApoE-/-) mice undergoing bilateral ovariectomy, fed a high-fat diet, and administered 109 colony-forming units (CFU) of LP for 13 consecutive weeks. LP intervention reduces total cholesterol (TC) and triglyceride (TG) accumulation in the serum and liver and accelerates their fecal excretion, which is mainly accomplished by increasing the excretion of fecal secondary bile acids (BAs), thereby facilitating cholesterol conversion. Correlation analysis revealed that lithocholic acid (LCA) is an important regulator of postmenopausal lipid abnormalities. LP can reduce LCA accumulation in the liver and serum while enhancing its fecal excretion, accomplished by elevating the relative abundances of Allobaculum and Olsenella in the ileum. Our findings demonstrate that postmenopausal lipid dysfunction is accompanied by abnormalities in BA metabolism and dysbiosis of the intestinal microbiota. LP holds therapeutic potential for postmenopausal hypercholesterolemia. Its effectiveness in ameliorating lipid dysregulation is primarily achieved through reshaping the diversity and abundance of the intestinal microbiota to correct BA abnormalities.

Decellularized laser micro-patterned osteochondral implants exhibit zonal recellularization and self-fixing for osteochondral regeneration in a goat model.

Background: Osteochondral regeneration has long been recognized as a complex and challenging project in the field of tissue engineering. In particular, reconstructing the osteochondral interface is crucial for determining the effectiveness of the repair. Although several artificial layered or gradient scaffolds have been developed recently to simulate the natural interface, the functions of this unique structure have still not been fully replicated. In this paper, we utilized laser micro-patterning technology (LMPT) to modify the natural osteochondral "plugs" for use as grafts and aimed to directly apply the functional interface unit to repair osteochondral defects in a goat model. Methods: For in vitro evaluations, the optimal combination of LMPT parameters was confirmed through mechanical testing, finite element analysis, and comparing decellularization efficiency. The structural and biological properties of the laser micro-patterned osteochondral implants (LMP-OI) were verified by measuring the permeability of the interface and assessing the recellularization processes. In the goat model for osteochondral regeneration, a conical frustum-shaped defect was specifically created in the weight-bearing area of femoral condyles using a customized trephine with a variable diameter. This unreported defect shape enabled the implant to properly self-fix as expected. Results: The micro-patterning with the suitable pore density and morphology increased the permeability of the LMP-OIs, accelerated decellularization, maintained mechanical stability, and provided two relative independent microenvironments for subsequent recellularization. The LMP-OIs with goat's autologous bone marrow stromal cells in the cartilage layer have securely integrated into the osteochondral defects. At 6 and 12 months after implantation, both imaging and histological assessments showed a significant improvement in the healing of the cartilage and subchondral bone. Conclusion: With the natural interface unit and zonal recellularization, the LMP-OI is an ideal scaffold to repair osteochondral defects especially in large animals. The translational potential of this article: These findings suggest that such a modified xenogeneic osteochondral implant could potentially be explored in clinical translation for treatment of osteochondral injuries. Furthermore, trimming a conical frustum shape to the defect region, especially for large-sized defects, may be an effective way to achieve self-fixing for the implant.