Nanomaterials and bone regeneration

The worldwide incidence of bone disorders and conditions has been increasing. Bone is a nanomaterials composed of organic （mainly collagen） and inorganic （mainly nano-hydroxyapatite） components, with a hierarchical structure ranging from nanoscale to macroscale. In consideration of the serious limitation in traditional therapies, nanomaterials provide some new strategy in bone regeneration. Nanostructured scaffolds provide a closer structural support approximation to native bone architecture for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. In this article, we focused on reviewing the classification and design of nanostructured materials and nanocarrier materials for bone regeneration, their cell interaction properties, and their application in bone tissue engineering and regeneration. Furthermore, some new challenges about the future research on the application of nanomaterials for bone regeneration are described in the conclusion and perspectives part.

The fabrication of biomimetic biphasic CAN-PAC hydrogel with a seamless interfacial layer applied in osteochondral defect repair

Cartilage tissue engineering based on biomimetic scaffolds has become a rapidly developing strategy for repairing cartilage defects. In this study, a biphasic CAN-PAC hydrogel for osteochondral defect(OCD)regeneration was fabricated based on the density difference between the two layers via a thermally reactive,rapid cross-linking method. The upper hydrogel was cross-linked by CSMA and NIPAm, and the lower hydrogel was composed of PECDA, AAm and PEGDA. The interface between the two layers was first grafted by the physical cross-linking of calcium gluconate and alginate, followed by the chemical cross-linking of the carbon-carbon double bonds in the other components. The pore sizes of the upper and lower hydrogels were ~ 187.4 and ~ 112.6 μm, respectively. The moduli of the upper and lower hydrogels were ~ 0.065 and~ 0.261 MPa. This prepared bilayer hydrogel exhibited the characteristics of mimetic composition, mimetic structure and mimetic stiffness, which provided a microenvironment for sustaining cell attachment and viability. Meanwhile, the biodegradability and biocompatibility of the CAN-PAC hydrogel were examined in vivo. Furthermore, an osteochondral defect model was developed in rabbits, and the bilayer hydrogels were implanted into the defect. The regenerated tissues in the bilayer hydrogel group exhibited new translucent cartilage and repaired subchondral bone, indicating that the hydrogel can enhance the repair of osteochondral defects.

Biomaterial-based strategies for maxillofacial tumour therapy and bone defect regeneration

Issues caused by maxillofacial tumours involve not only dealing with tumours but also repairing jaw bone defects.In traditional tumour therapy,the systemic toxicity of chemotherapeutic drugs,invasive surgical resection,intractable tumour recurrence,and metastasis are major threats to the patients’lives in the clinic.Fortunately,biomaterial-based intervention can improve the efficiency of tumour treatment and decrease the possibility of recurrence and metastasis,suggesting new promising antitumour therapies.In addition,maxillofacial bone tissue defects caused by tumours and their treatment can negatively affect the physiological and psychological health of patients,and investment in treatment can result in a multitude of burdens to society.Biomaterials are promising options because they have good biocompatibility and bioactive properties for stimulation of bone regeneration.More interestingly,an integrated material regimen that combines tumour therapy with bone repair is a promising treatment option.Herein,we summarized traditional and biomaterial-mediated maxillofacial tumour treatments and analysed biomaterials for bone defect repair.Furthermore,we proposed a promising and superior design of dual-functional biomaterials for simultaneous tumour therapy and bone regeneration to provide a new strategy for managing maxillofacial tumours and improve the quality of life of patients in the future.

Review of a new bone tumor therapy strategy based on bifunctional biomaterials

Bone tumors,especially those in osteosarcoma,usually occur in adolescents.The standard clinical treatment includes chemotherapy,surgical therapy,and radiation therapy.Unfortunately,surgical resection often fails to completely remove the tumor,which is the main cause of postoperative recurrence and metastasis,resulting in a high mortality rate.Moreover,bone tumors often invade large areas of bone,which cannot repair itself,and causes a serious effect on the quality of life of patients.Thus,bone tumor therapy and bone regeneration are challenging in the clinic.Herein,this review presents the recent developments in bifunctional biomaterials to achieve a new strategy for bone tumor therapy.The selected bifunctional materials include 3D-printed scaffolds,nano/microparticle-containing scaffolds,hydrogels,and bone-targeting nanomaterials.Numerous related studies on bifunctional biomaterials combining tumor photothermal therapy with enhanced bone regeneration were reviewed.Finally,a perspective on the future development of biomaterials for tumor therapy and bone tissue engineering is discussed.This review will provide a useful reference for bone tumor-related disease and the field of complex diseases to combine tumor therapy and tissue engineering.

大n值准相纯二维卤化物钙钛矿:从材料到器件的工具箱

Despite their excellent environmental stability,low defect density,and high carrier mobility,large-n quasi-two-dimensional halide perovskites(quasi-2DHPs)feature a limited application scope because of the formation of self-assembled multiple quantum wells(QWs)due to the similar thermal stabilities of large-n phases.However,large-n quasi-phase-pure 2DHPs(quasi-PP-2DHPs)can solve this problem perfectly.This review discusses the structures,formation mechanisms,and photoelectronic and physical properties of quasi-PP-2DHPs,summarises the corresponding single crystals,thin films,and heterojunction preparation methods,and presents the related advances.Moreover,we focus on applications of large-n quasi-PP-2DHPs in solar cells,photodetectors,lasers,light-emitting diodes,and field-effect transistors,discuss the challenges and prospects of these emerging photoelectronic materials,and review the potential technological developments in this area.

Hydrogel platform with tunable stiffness based on magnetic nanoparticles cross-linked GelMA for cartilage regeneration and its intrinsic biomechanism

Cartilage injury affects numerous individuals,but the efficient repair of damaged cartilage is still a problem in clinic.Hydrogel is a potent scaffold candidate for tissue regeneration,but it remains a big challenge to improve its mechanical property and figure out the interaction of chondrocytes and stiffness.Herein,a novel hybrid hydrogel with tunable stiffness was fabricated based on methacrylated gelatin(GelMA)and iron oxide nanoparticles(Fe_(2)O_(3))through chemical bonding.The stiffness of Fe_(2)O_(3)/GelMA hybrid hydrogel was controlled by adjusting the concentration of magnetic nanoparticles.The hydrogel platform with tunable stiffness modulated its cellular properties including cell morphology,microfilaments and Young’s modulus of chondrocytes.Interestingly,Fe_(2)O_(3)/GelMA hybrid hydrogel promoted oxidative phosphorylation of mitochondria and facilitated catabolism of lipids in chondrocytes.As a result,more ATP and metabolic materials generated for cellular physiological activities and organelle component replacements in hybrid hydrogel group compared to pure GelMA hydrogel.Furthermore,implantation of Fe_(2)O_(3)/GelMA hybrid hydrogel in the cartilage defect rat model verified its remodeling potential.This study provides a deep understanding of the bio-mechanism of Fe_(2)O_(3)/GelMA hybrid hydrogel interaction with chondrocytes and indicates the hydrogel platform for further application in tissue engineering.

通过相对论重粒子碰撞中的J/ψ产生揭秘胶子喷注淬火机制

长久以来,喷注淬火被认为是探测重离子碰撞中形成的夺克胶子等离子体的关键信号之一,尽管过去在喷注火研究方面已经付出了巨大的努力、但是区分夸克和胶子的喷注淬火仍然是一个非常大的挑战本文发现大横动量J/主要由胶子碎裂产生,因此为探测胶子在热密介质中的能量损失提供了一个独特的敏感探针,作者首先基于领头幂次的NRQCD因子化理论计算了质子-质子碰撞中的大横动量J/产生,发现胶子碎裂是大横动量J/产生的主要机制,然后通过线性玻尔兹曼输运模型和相对论流体力学模拟了核-核碰撞中喷注与热密介质的相互作用,所得数值结果很好地描述了大横动量J/的核修正因子和椭圆流,揭示出胶子能量损失是大横动量J/产额压低的主要机制。作者进一步通过数据驱动的贝叶斯分析方法证实了这个新颖的结论,并定量提取出夸克胶子等离子体中的胶子能量损失分布。

Gold nanorods and nanohydroxyapatite hybrid hydrogel for preventing bone tumor recurrence via postoperative photothermal therapy and bone regeneration promotion

Osteosarcoma is a malignant bone tumor,which often occurs in adolescents.However,surgical resection usually fails to completely remove the tumor clinically,which has been the main cause of postoperative recurrence and metastasis,resulting in the high death rate of patients.At the same time,osteosarcoma invades a large area of the bone defect,which cannot be self-repaired and seriously affects the life quality of the patients.Herein,a bifunctional methacrylated gelatin/methacrylated chondroitin sulfate hydrogel hybrid gold nanorods(GNRs)and nanohydroxyapatite(nHA),which possessed excellent photothermal effect,was constructed to eradicate residual tumor after surgery and bone regeneration.In vitro,K7M2wt cells(a mouse bone tumor cell line)can be efficiently eradicated by photothermal therapy of the hybrid hydrogel.Meanwhile,the hydrogel mimics the extracellular matrix to promote proliferation and osteogenic differentiation of mesenchymal stem cells.The GNRs/nHA hybrid hydrogel was capable of photothermal treatment of postoperative tumors and bone defect repair in a mice model of tibia osteosarcoma.Therefore,the hybrid hydrogel possesses dual functions of tumor therapy and bone regeneration,which shows great potential in curing bone tumors and provides a new hope for tumor-related bone complex disease.

The design,mechanism and biomedical application of self-healing hydrogels

Hydrogels are promising materials with outstanding characteristics such as tunable and reversible physical/chemical properties,stimuli-responsiveness,biomimetic,and biocompatibility.However,the structural and functional integrity of the hydrogels can be compromised by external mechanical forces or chemical erosion when used,especially in sophisticated in vivo environment.To address this problem,self-healing hydrogels which possess the intrinsic ability of self-repair have been developed to adapt to destructive factors.In this review,we focused on the current advances made in self-healing hydrogels.First,the testing methods for self-healing hydrogels were summarized.Then,we looked into the designing strategies of self-healing hydrogels and illustrated the self-healing mechanism.What＇s more,the biomedical application of self-healing hydrogels in vivo was discussed.

Global constraints from RHIC and LHC on transport properties of QCD fluids in CUJET/CIBJET framework

We report results of a comprehensive global х~2 analysis of nuclear collision data from RHIC(0.2 ATeV),LHC1(2.76 ATeV), and recent LHC2(5.02 ATeV) energies using the updated CUJET framework. The framework consistently combines viscous hydrodynamic fields predicted by VISHNU2+1(validated with soft p_T﹤2 GeV bulk observables) and the DGLV theory of jet elastic and inelastic energy loss generalized to QGP fluids with an sQGMP color structure, including effective semi-QGP color electric quark and gluon as well as emergent color magnetic monopole degrees of freedom constrained by lattice QCD data. We vary the two control parameters of the model(the maximum value of the running QCD coupling, c, and the ratio cm of color magnetic to electric screening scales) and calculate the global х~2(α_c,c_m) compared with available jet fragment observables( R_(AA),v_2). A global х~2 minimum is found with α_c≈0.9±0.1 and c_m≈0.25±0.03. Using CIBJET, the event-by-event(ebe) generalization of the CUJET framework, we show that ebe fluctuations in the initial conditions do not significantly alter our conclusions(except for v_3). An important theoretical advantage of the CUJET and CIBJET frameworks is not only its global х~2 consistency with jet fragment observables at RHIC and LHC and with non-perturbative lattice QCD data, but also its internal consistency of the constrained jet transport coefficient, ■(E,T)/T^3, with the near-perfect fluid viscosity to entropy ratio(η/s～T^3/■～0.1-0.2) property of QCD fluids near Tc needed to account for the low p_T﹤2 GeV flow observables. Predictions for future tests at LHC with 5.44 ATeV Xe + Xe and 5.02 ATeV Pb + Pb are also presented.

Investigation of experimental observables in search of the chiral magnetic effect in heavy-ion collisions in the STAR experiment

The chiral magnetic effect(CME)is a novel transport phenomenon,arising from the interplay between quantum anomalies and strong magnetic fields in chiral systems.In high-energy nuclear collisions,the CME may survive the expansion of the quark-gluon plasma fireball and be detected in experiments.Over the past two decades,experimental searches for the CME have attracted extensive interest at the Relativistic Heavy Ion Collider(RHIC)and the Large Hadron Collider(LHC).The main goal of this study is to investigate three pertinent experimental approaches:the$\gamma$correlator,the R correlator,and the signed balance functions.We exploit simple Monte Carlo simulations and a realistic event generator(EBE-AVFD)to verify the equivalence of the core components among these methods and to ascertain their sensitivities to the CME signal and the background contributions for the isobar collisions at the RHIC.

Chiral magnetic effect in isobar collisions from stochastic hydrodynamics

We studied the chiral magnetic effect in AuAu,RuRu,and ZrZr collisions at sNN−√=200GeV.The axial charge evolution was modeled with stochastic hydrodynamics,and geometrical quantities were calculated with the Monte Carlo Glauber model.By adjusting the relaxation time of the magnetic field,we found our results are in good agreement with background subtracted data for AuAu collisions at the same energy.We also made predictions for RuRu and ZrZr collisions.We found a weak centrality dependence on initial chiral imbalance,which implies that the centrality dependence of chiral magnetic effect signals results mainly from the effects of the magnetic field and volume factor.Furthermore,our results show an unexpected dependence on system size.While the AuAu system has larger chiral imbalance and magnetic field,it was observed to have a smaller signal for the chiral magnetic effect due to the larger volume suppression factor.

Probing the color structure of the perfect QCD fluids via soft-hard-event-by-event azimuthal correlations

We develop a comprehensive dynamical framework, CIBJET, to calculate on an event-by-event basis the dependence of correlations between soft （PT 〈2 GeV） and hard （PT 〉 10 GeV） azimuthal flow angle harmonics on the color composition of near-perfect QCD fluids produced in high energy nuclear collisions at RHIC and LHC. CIBJET combines consistently predictions of event-by-event VISHNU2＋I viscous hydrodynamic fluid fields with CUJET3.1 predictions of event-by-event jet quenching. We find that recent correlation data favor a temperature dependent color composition including bleached chromo-electric q（T）＋g（T） components and an emergent chromo-magnetic degrees of freedom re（T） consistent with non-perturbative lattice QCD information in the confinement/deconfinement temperature range.

A potential flower-like coating consisting of calcium-phosphate nanosheets on titanium surface

Titanium and its alloys have been widely used as implant materials in bio-medicine.Additionally,surface modification has been utilized to improve the chemical and morphological properties of materials.More specifically,biocoating,especially the calcium-phosphate nano-coating,has been widely used in the research field.In this study,a novel calcium-phosphate nanoflower coating was performed on the titanium surface by a simple approach.This study indicated that the novel calcium-phosphate flower-like coating consisting of calcium-phosphate nanosheets had high surface area,low cytotoxicity as well as promising cell affinity.Hence it could be a potential alternative modification method for titanium.