Chemical looping reforming of the micromolecular component from biomass pyrolysis via Fe_(2)O_(3)@SBA-16

To solve the problems of low gasification efficiency and high tar content caused by solid–solid contact between biomass and oxygen carrier in traditional biomass chemical looping gasification process.The decoupling strategy was adopted to decouple the biomass gasification process,and the composite oxygen carrier was prepared by embedding Fe_(2)O_(3) in molecular sieve SBA-16 for the chemical looping reforming process of pyrolysis micromolecular model compound methane,which was expected to realize the directional reforming of pyrolysis volatiles to prepare hydrogen-rich syngas.Thermodynamic analysis of the reaction system was carried out based on the Gibbs free energy minimization method,and the reforming performance was evaluated by a fixed bed reactor,and the kinetic parameters were solved based on the gas–solid reaction model.Thermodynamic analysis verified the feasibility of the reaction and provided theoretical guidance for experimental design.The experimental results showed that the reaction performance of Fe_(2)O_(3)@SBA-16 was compared with that of pure Fe_(2)O_(3) and Fe_(2)O_(3)@SBA-15,and the syngas yield was increased by 55.3%and 20.7%respectively,and it had good cycle stability.Kinetic analysis showed that the kinetic model changed from three-dimensional diffusion to first-order reaction with the increase of temperature.The activation energy was 192.79 kJ/mol by fitting.This paper provides basic data for the directional preparation of hydrogen-rich syngas from biomass and the design of oxygen carriers for pyrolysis of all-component chemical looping reforming.

Chemical looping gasification of maceral from low-rank coal: Products distribution and kinetic analysis on vitrinite

The product distribution and kinetic analysis of low-rank coal vitrinite were investigated during the chemical looping gasification(CLG)process.The acid washing method was used to treat low-rank coal,and the density gradient centrifugation method was adopted to obtain the coal macerals.By combining thermogravimetric analysis and online mass spectrometry,the influence of the heating rate and oxygen carrier(Fe2O3)blending ratio on product distribution was discussed.The macroscopic kinetic parameters were solved by the Kissinger-Akahira-Sunose(KAS)method,and the main gaseous product formation kinetic parameters were solved by the iso-conversion method.The results of vitrinite during slow heating chemical looping gasification showed that the main weight loss interval was 400–600℃,and the solid yield of sample vitrinite-Fe-10 at different heating rates was 64.30%–69.67%.When b=20℃·min^(-1),the maximum decomposition rate of vitrinite-Fe-10 was 0.312%min1.The addition of Fe2O_(3)reduced the maximum decomposition rate,but by comparing the chemical looping conversion characteristic index,it could be inferred that the chemical looping gasification of vitrinite might produce volatile substances higher than the pyrolysis process of vitrinite alone.The average activation energy of the reaction was significantly reduced during chemical looping gasification of vitrinite,which was lower than the average activation energy of 448.69 kJ·mol^(-1) during the pyrolysis process of vitrinite alone.The gaseous products were mainly CO and CO_(2).When the heating rate was 10℃·min^(-1),the highest activation energy for CH4 formation was 21.353 kJ·mol^(-1),and the lowest activation energy for CO formation was 9.7333 kJ·mol^(-1).This study provides basic data for exploring coal chemical looping gasification mechanism and reactor design by studying the chemical looping gasification process of coal macerals。

Liquid chemical looping gasification of biomass:Thermodynamic analysis on cellulose

Liquid chemical looping technology is an innovation of chemical looping conversion technology.Using liquid metal oxide as the oxygen carrier during gasification process could prolong the service life of oxygen carrier and improve the process efficiency.In this paper,based on Gibbs minimum free energy method,the thermodynamic characteristics of biomass liquid chemical looping gasification were studied.Cellulose and lignin,the main components of biomass,were taken as the research objects.Bismuth oxide and antimony oxide were selected as liquid oxygen carriers.The results showed that when the temperature increased from 600℃to 900℃,the output of H_(2)and CO in the products of cellulose gasification increased from 0.5 and 0.3 kmol to 1.3 and 2.6 kmol respectively.Different ratios of oxygen carriers to gasification raw materials had the best molar ratio.The addition of steam in the system was beneficial to the increase of H_(2)content and the increase of H_(2)/CO molar ratio.Bi_(2)O_(3)and Sb_(2)O_(3)with different mass ratios were used as mixed oxygen carriers.The simulation results showed that the gasification temperature of biomass with different mixed oxygen carriers had the same equilibrium trend products.It could be seen from the results of product distribution that the influence of the mixing ratio of Bi_(2)O_(3)and Sb_(2)O_(3)on gas product distribution could be neglected.These results could provide simulation reference and data basis for subsequent research on liquid chemical looping gasification.

A biomimetic nanoplatform for customized photothermal therapy of HNSCC evaluated on patient-derived xenograft models

Cancer cell membrane(CCM)derived nanotechnology functionalizes nanoparticles(NPs)to recognize homologous cells,exhibiting translational potential in accurate tumor therapy.However,these nanoplatforms are majorly generated from fixed cell lines and are typically evaluated in cell line-derived subcutaneous-xenografts(CDX),ignoring the tumor heterogeneity and differentiation from inter-and intra-individuals and microenvironments between heterotopic-and orthotopic-tumors,limiting the therapeutic efficiency of such nanoplatforms.Herein,various biomimetic nanoplatforms(CCM-modified gold@Carbon,i.e.,Au@C-CCM)were fabricated by coating CCMs of head and neck squamous cell carcinoma(HNSCC)cell lines and patient-derived cells on the surface of Au@C NP.The generated Au@C-CCMs were evaluated on corresponding CDX,tongue orthotopic xenograft(TOX),immunecompetent primary and distant tumor models,and patient-derived xenograft(PDX)models.The Au@C-CCM generates a photothermal conversion efficiency up to 44.2% for primary HNSCC therapy and induced immunotherapy to inhibit metastasis via photothermal therapy-induced immunogenic cell death.The homologous CCM endowed the nanoplatforms with optimal targeting properties for the highest therapeutic efficiency,far above those with mismatched CCMs,resulting in distinct tumor ablation and tumor growth inhibition in all four models.This work reinforces the feasibility of biomimetic NPs combining modular designed CMs and functional cores for customized treatment of HNSCC,can be further extended to other malignant tumors therapy.

Recent progress in ternary mixed matrix membranes for CO_(2) separation

Mixed matrix membranes(MMMs)could combine the advantages of both polymeric membranes and porousfillers,making them an effective alternative to conventional polymer membranes.However,interfacial incompatibility issues,such as the presence of interfacial voids,hardening of polymer chains,and blockage of micropores by polymers between common MMMsfillers and the polymer matrix,currently limit the gas sep-aration performance of MMMs.Ternary phase MMMs(consisting of afiller,an additive,and a matrix)made by adding a third compound,usually functionalized additives,can overcome the structural problems of binary phase MMMs and positively impact membrane separation performance.This review introduces the structure and fabrication processes for ternary MMMs,categorizes various nanofillers and the third component,and summarizes and analyzes in detail the CO_(2) separation performance of newly developed ternary MMMs based on both rubbery and glassy polymers.Based on this separation data,the challenges of ternary MMMs are also discussed.Finally,future directions for ternary MMMs are proposed.

MoS2 nanorods with inner caves through synchronous encapsulation of sulfur for high performance Li–S cathodes

Lithium–sulfur(Li–S)batteries have become one of the most promising candidates for next-generation batteries owing to their high specific capacity,low cost,and environment-friendliness.Many efforts have been made to mitigate the"shuttle effect"through physical adsorption and chemical bonding.MoS2 has been proposed as a cathode material to provide effective anchoring sites for lithium polysulfides(Li PSs),but is still limited by its layer structure.Herein,we designed novel MoS2 nanorods with inner caves based on our previous work,and performed synchronous encapsulation of sulfur during the synthesis process.The outer MoS2 tubular shells physically inhibit the outward diffusion of polysulfide species while the inner particles chemically anchor the polysulfides to prevent shuttling.As the cathode matrix in Li–S batteries,the electrochemical results deliver a high initial discharge capacity of 1213 mAhg^-1 for sulfur at 0.1 C.After cycling at 1 C for 300 cycles,the cells exhibit a capacity decay of only 0.076%per cycle and high average coulombic efficiency over 95%.The tubular MoS2 structure is an innovative and appealing design,which could be regarded as a prospective substrate for the improved performance of Li–S batteries.

Coupling pinch analysis and rigorous process simulation for hydrogen networks with light hydrocarbon recovery

In refineries,some hydrogen-rich streams contain considerable light hydrocarbons that are important raw materials for the chemical industry.Integrating hydrogen networks with light hydrocarbon recovery can enhance the reuse of both hydrogen and light hydrocarbons.This work proposes an automated method for targeting hydrogen networks with light hydrocarbon recovery.A pinch-based algebraic method is improved to determine the minimum fresh hydrogen consumption and hydrogen sources fed into the light hydrocarbon recovery unit automatically.Rigorous process simulation is conducted to determine the mass and energy balances of the light hydrocarbon recovery process.The targeting procedures are developed through combination of the improved pinch method and rigorous process simulation.This hybrid method is realized by coupling the Matlab and Aspen HYSYS platforms.A refinery hydrogen network is analyzed to illustrate application of the proposed method.The integration of hydrogen network with light hydrocarbon recovery further reduces fresh hydrogen requirement by463.0 m^(3)·h^(-1) and recovers liquefied petroleum gas and gasoline of 1711.5 kg·h^(-1) and 643 kg·h^(-1),respectively.A payback period of 9.2 months indicates that investment in light hydrocarbon recovery is economically attractive.

Reaction Mechanism of One-Step Conversion of Ethanol to 1,3-Butadiene over Zn-Y/BEA and Superior Catalysts Screening

The one-step conversion of ethanol to 1,3-butadiene has achieved a breakthrough with the development of beta zeolite supported dual metal catalysts.However,the reaction mechanism from ethanol to butadiene is complex and has not yet been fully elucidated,and no catalyst screening effort has been done based on central metal atoms.In this work,density functional theory(DFT)calculations were employed to study the mechanism of one-step conversion of ethanol to butadiene over ZnY/BEA catalyst.The results show that ethanol dehydrogenation prefers to proceed on Zn site with a reaction energy of 0.77 eV in the rate-determining step,and the aldol condensation to produce butadiene prefers to proceed on Y site with a reaction energy of 0.69 eV in the rate-determining step.Based on the mechanism revealed,six elements were selected to replace Y for screening superior combination of Zn-M/BEA(M=Sn,Nb,Ta,Hf,Zr,Ti;BEA:beta polymorph A)for this reaction.As a result,Zn-Y/BEA(0.69 eV)is proven to be the most preferring catalyst compared with the other six ones,and Zn-Zr/BEA(0.85 eV),Zn-Ti/BEA(0.87 eV),and Zn-Sn/BEA(0.93 eV)can be potential candidates for the conversion of ethanol to butadiene.This work not only provides mechanistic insights into one-step catalytic conversion of ethanol to butadiene over Zn-Y/BEA catalyst but also offers more promising catalyst candidates for this reaction.

Efficient conversion of benzene and syngas to toluene and xylene over ZnO-ZrO_(2)&H-ZSM-5 bifunctional catalysts

A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.

Numerical investigation for the suitable choice of bubble diameter correlation for EMMS/bubbling drag model

Mesoscale bubbles exist inherently in bubbling fluidized beds and hence should be considered in the constitutive modeling of the drag force.The energy minimization multiscale bubbling(EMMS/bubbling)drag model takes the effects of mesoscale structures(i.e.,bubbles)into the modeling of drag coefficient and thus improves the coarse-grid simulation of bubbling and turbulent fluidized beds.However,its dependence on the bubble diameter correlation has not been thoroughly investigated.The hydrodynamic disparity between homogeneous and heterogeneous fluidization is accounted for by the heterogeneity index,H_(d),which can be affected by choice of bubble diameter correlation.How this choice of bubble diameter correlation influences the model prediction calls for further fundamental research.This article incorporated seven different bubble diameter correlations into EMMS/bubbling drag model and studied their effects on H_(d).The performance of these correlations has been compared with the correlation used previously by EMMS/bubbling drag model.We found that some of the correlations predicted lower Hd by order of a magnitude than the correlation used by the original EMMS/bubbling drag.Based on such analysis,we proposed a modification in the EMMS drag model for bubbling and turbulent fluidized beds.A computational fluid dynamics(CFD)simulation using two-fluid model with the modified EMMS/bubbling drag model was performed for two bubbling and one turbulent fluidized beds.Voidage distribution,time averaged solid concentration and axial solid concentration profiles were studied and compared with the previous version of the EMMS/bubbling drag model and experimental data.We found that the right choice of bubble diameter correlations can significantly improve the results for CFD simulations.

Role of surface frustrated Lewis pairs on reduced CeO2(110)in direct conversion of syngas

Direct syngas conversion to light olefins on bifunctional oxide-zeolite(OX-ZEO)catalysts is of great interest to both academia and industry,but the role of oxygen vacancy(Vo)in metal oxides and whether the key intermediate in the reaction mechanism is ketene or methanol are still not well-understood.To address these two issues,we carry out a theoretical study of the syngas conversion on the typical reducible metal oxide,CeO2,using density functional theory calculations.Our results demonstrate that by forming frustrated Lewis pairs(FLPs),the VOs in CeO2 play a key role in the activation of H2 and CO.The activation of H2 on FLPs undergoes a heterolytic dissociative pathway with a tiny barrier of 0.01 eV,while CO is activated on FLPs by combining with the basic site(O atom)of FLPs to form CO2^2-.Four pathways for the conversion of syngas were explored on FLPs,two of which are prone to form ketene and the other two are inclined to produce methanol suggesting a compromise to resolve the debate about the key intermediates(ketene or methanol)in the experiments.Rate constant calculations showed that the route initiating with the coupling of two CO*into OCCO*and ending with the formation of ketene is the dominant pathway,with the neighboring FLPs playing an important role in this pathway.Overall,our study reveals the function of the surface FLPs in the activation of H2 and CO and the reaction mechanism for the production of ketene and methanol for the first time,providing novel insights into syngas conversion over OX-ZEO catalysts.

Application and progress of techno-economic analysis and life cycle assessment in biomanufacturing of fuels and chemicals

To reduce the dependency on petroleum-based products and emission of greenhouse gas,renewable biofuels and chemicals play an important role to meet the unmatched energy demands of the rapidly growing population.However,most biofuel and chemical products do not reach the commercialization stage,mainly hindered by incomparable economics to petroproducts.Techno-economic assessment(TEA)is a useful tool to estimate eco-nomic performance,and identify bottlenecks for the development of biofuel and chemical production technology,meanwhile,life cycle assessment(LCA)is applied to assess sustainability by reducing the environmental impact of biofuel and chemical production.This present review covers TEA and LCA research progress in the manufacturing of biofuels and biochemical,and discusses the impacts of TEA and LCA results on the development and optimi-zation of biofuel and chemical production.In addition,challenges associated with TEA and LCA of biofuel and biochemical production were briefly overviewed,and potential approaches that may overcome such challenges were discussed enabling viable and sustainable biomanufacturing of fuels and chemicals.Future integrated TEA and LCA studies could significantly promote the economic and sustainable development of the biomanufacturing process.

One-step conversion of methane and formaldehyde to ethanol over SA-FLP dual-active-site catalysts: A DFT study

One-step conversion of methane and formaldehyde into ethanol is a 100% atom-efficient process for carbon resources utilization and environment protection but still faces eminent challenges due to the lacking of efficient catalysts. Therefore, developing active and stable catalysts is crucial for the co-conversion of methane and formaldehyde. Herein, twelve kinds of “Single-Atom”-“Frustrated Lewis Pair”(SA-FLP)dual-active-site catalysts are designed for the direct conversion of methane and formaldehyde to ethanol based on density functional theory(DFT) calculations and microkinetic simulations. The results show that the SA-FLP dual active sites can simultaneously activate methane at the SA site and activate formaldehyde at the FLP site. Among the twelve designed SA-FLP catalysts, Fe1-FLP shows the best performance in the co-conversion of methane and formaldehyde to ethanol with the rate-determining barrier of 1.15 e V.Ethanol is proved as the main product with the turnover frequency of 1.32 × 10^(-4)s^(-1)at 573 K and 3 bar.This work provides a universal strategy to design dual active sites on metal oxide materials and offers new insights into the effective conversion of methane and formaldehyde to desired C_(2) chemicals.

A universal strategy for the refined frameworks and improved performance of distinct commercial polyacrylonitriles in sulfur cathodes

Sulfurized polyacrylonitrile(SPAN)with the exceptional stability,safety,low cost,and high capacity have been positioned as a highly promising cathode material for next-generation lithium-ion batteries.However,in the market,polyacrylonitrile(PAN)sourced from different suppliers and available at varying prices exhibits significant variations in physical and chemical properties,resulting in diverse behaviors in Li-SPAN batteries.By studying the mechanism,we found that the PAN copolymerization structure leads to the stacking of chain segments which obstructs the embedding of sulfur and lithium ions.Here,we propose a universal strategy for the refined frameworks by an exogenous additive to modify various PAN raw materials,and the battery capacity and cycling performance are obviously improved.As a result,the copolymerized SPAN with a poor original capacity is nearly doubled to over 500 mAh g^(-1),almost comparable to high-quality yet expensively imported products;for the sample with a high initial capacity but fading in ether-based electrolytes,it can be modified to maintain stability over 400 cycles.This strategy offers an alternative approach for SPAN modification that is characterized by its simplicity and low cost,thereby facilitating the large-scale development of Li-SPAN batteries.

Chemical looping gasification characteristics and kinetic analysis of Chlorella and its organic components

Chemical looping gasification(CLG)characteristics and kinetic analysis of Chlorella(CHL),simulated Chlorella(V-CHL)and medium-chain triglycerides(MCT)were investigated using a thermogravimetric analyzer coupled with an online mass spectrometer.The apparent activation energy was obtained via Kissinger-Akahira-Sunose(KAS)method.In the result of the weightless behavior,the addition of oxygen carrier inhibited the decomposition of V-CHL at lower temperatures but promoted its decomposition at high temperatures.The values of chemical looping process characteristic parameters showed that a 10 wt%oxygen carrier would maximize the release of volatile products in the CLG of MCT,with 5.12×10^(-6)%⋅min^(-1)⋅℃^(-3).Oxygen carriers also affected gaseous products.The LHV of gaseous products of CHL reached the largest when the oxygen carrier was 10 wt%,which was 8.13 MJ/m^(3).And the gaseous product of MCT had the largest LHV with 30 wt%oxygen carrier,which was 8.83 MJ/m^(3).According to the kinetic analysis,the minimum value of apparent activation energy of MCT chemical looping gasification was 89.54 kJ⋅mol^(-1) with the oxygen carrier of 30 wt%,which was 50%less than that of MCT pyrolysis.And the minimum value for V-CHL was obtained when the mass fraction of Fe2O3 was 50 wt%.This paper could provide a reference for the choice of algae,the design of reactors,and the targeted regulation of the gaseous product for the algae CLG process.

Exergy and exergoeconomic analyses for integration of aromatics separation with aromatics upgrading

Methanol to aromatics produces multiple products,resulting in a limited selectivity of xylene.Aromatics upgrading is an effective way to produce more valuable xylene product,and different feed ratios generate discrepant product distributions.This work integrates the aromatics separation with toluene disproportionation,transalkylation of toluene and trimethylbenzene,and isomerization of xylene and trimethylbenzene.Exergy and exergoeconomic analyses are conducted to give insights in the splitting ratios of benzene,toluene and heavy aromatics for aromatics upgrading.First,a detailed simulation model is developed in Aspen HYSYS.Then,300 splitting ratio sets of benzene and toluene for conversion are studied to investigate the process performances.The results indicate that there are different preferences for the splitting ratios of benzene and toluene in terms of exergy and exergoeconomic performances.The process generates lower total exergy destruction when the splitting ratio of toluene varies between 0.07 and 0.18,and that of benzene fluctuates between 0.55 and 0.6.Nevertheless,the process presents lower total product unit cost with the splitting ratio of toluene less than 0.18 and that of benzene fluctuating between 0.44 and 0.89.Besides,it is found that distillation is the biggest contributor to the total exergy destruction,accounting for 94.97%.

Bifunctional additive phenyl vinyl sulfone for boosting cyclability of lithium metal batteries

One of the bottlenecks limiting the cycling stability of high voltage lithium metal batteries(LMBs)is the lack of suitable electrolytes.Herein,phenyl vinyl sulfone(PVS)is proposed as a multifunctional additive to stabilize both cathode and anode interfaces as it can be preferentially oxidized/reduced on the electrode surfaces.The PVS derived solid electrolyte interphase films can not only reduce the transition metal dissolution on the cathode side,but also suppress the Li dendrite spread on the lithium anode side.The Li||Li symmetric battery with PVS addition delivers longer cycle life and a higher critical current density of over 3.0 m Ah cm^(-2).The LiNi_(0.8)Co_(0.1)Mn0.1O_(2)(NCM811)||Li full cell exhibits excellent capacity retention of 80.8%or 80.0%after 400 cycles at 0.5 C or 1 C rate with the voltage range of 3.0–4.3 V.In particular,the NCM811||Li cell under constrained conditions remains operation over 150 cycles.This work offers new insights into the electrolyte formulations for the next generation of LMBs.

Self-adaptive hydrogel for breast cancer therapy via accurate tumor elimination and on-demand adipose tissue regeneration

The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer treatment.Herein,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to treat breast cancer via accurate tumor elimination,on-demand adipose tissue regeneration and effective infection inhibition.The hydrogel consisted of thiol groups ended polyethylene glycol(SH-PEG-SH)and doxorubicin encapsulated mesoporous silica nanocarriers(DOX@MSNs)double crosslinked hyaluronic acid(HA)after loading of antibacterial peptides(AP)and adipose-derived stem cells(ADSCs).A pH-cleavable unsaturated amide bond was pre-introduced between MSNs and HA frame to perform the tumor-specific acidic environment dependent DOX@MSNs release,meanwhile an esterase degradable glyceryl dimethacrylate cap was grafted on MSNs,which contributed to the selective chemotherapy in tumor cells with over-expressed esterase.The bond cleavage between MSNs and HA would also cause the swelling of the hydrogel,which not only provide sufficient space for the growth of ADSCs,but allows the hydrogel to fully fill the irregular defects generated by surgery and residual tumor atrophy,resulting in the on-demand regeneration of adipose tissue.Moreover,the sustained release of AP could be simultaneously triggered along with the size change of hydrogel,which further avoided bacterial infection to promote tissue regeneration.

Stimuli responsive co-delivery of celecoxib and BMP2 from micro-scaffold for periodontal disease treatment

Controlling inflammation meanwhile facilitating tissue regeneration has been considered as a promising strategy to treat inflammatory bone defect. Herein, we describe the synthesis of a bio-sensitive poly(lactic-co-glycolic acid)/mesoporous silica nanocarriers core-shell porous microsphere(PLGA/MSNsPMS) encapsulated poly(L-lactic acid)(PLLA) spongy nanofibrous micro-scaffold as a new generation of therapeutic platform for effective reconstruction of bone defects caused by periodontal diseases.The PLGA/MSNs-PMS were designed as stimuli-responsive carriers for on-demand co-delivery of multiple biomolecules to provide proper physiological environment, while the multi-level(from macro-,micro-to nanometers) nanofibrous and porous structures in PLLA micro-scaffold were in charge of the reconstruction of ECM, which synergistically contribute to the enhancement of new tissue formation under inflammatory condition. After local injection into periodontal tissue, this construct could sequentially release bone growth factor(BMP-2) as well as anti-inflammatory drug(celecoxib) loaded MSNs in response to the over-expressed matrix metalloproteinases(MMP) in periodontal region. During alveolar bone regeneration induced by BMP-2 and ECM like structure, the MSNs would further deliver celecoxib in target cells to achieve inflammation inhibition, resulting in effective treatment of periodontal disease.

Bioinspired drug-delivery system emulating the natural bone healing cascade for diabetic periodontal bone regeneration

Diabetes mellitus(DM)aggravates periodontitis,resulting in accelerated periodontal bone resorption.Disordered glucose metabolism in DM causes reactive oxygen species(ROS)overproduction resulting in compromised bone healing,which makes diabetic periodontal bone regeneration a major challenge.Inspired by the natural bone healing cascade,a mesoporous silica nanoparticle(MSN)-incorporated PDLLA(poly(DL-lactide))-PEG-PDLLA(PPP)thermosensitive hydrogel with stepwise cargo release is designed to emulate the mesenchymal stem cell“recruitment-osteogenesis”cascade for diabetic periodontal bone regeneration.During therapy,SDF-1 quickly escapes from the hydrogel due to diffusion for early rat bone marrow stem cell(rBMSC)recruitment.Simulta-neously,slow degradation of the hydrogel starts to gradually expose the MSNs for sustained release of metformin,which can scavenge the overproduced ROS under high glucose conditions to reverse the inhibited osteogenesis of rBMSCs by reactivating the AMPK/β-catenin pathway,resulting in regulation of the diabetic microenvironment and facilitation of osteogenesis.In vitro experiments indicate that the hydrogel markedly restores the inhibited migration and osteogenic capacities of rBMSCs under high glucose conditions.In vivo results suggest that it can effectively recruit rBMSCs to the periodontal defect and significantly promote periodontal bone regeneration under type 2 DM.In conclusion,our work provides a novel therapeutic strategy of a bioinspired drug-delivery system emulating the natural bone healing cascade for diabetic periodontal bone regeneration.