Measurements of the effective mass transfer areas for the gas–liquid rotating packed bed

Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.

Efficient and rapid conversion of human astrocytes and ALS mouse model spinal cord astrocytes into motor neuron-like cells by defined small molecules

Background: Motor neuron degeneration or loss in the spinal cord is the characteristic phenotype of motor neuron diseases or spinal cord injuries. Being proliferative and located near neurons, astrocytes are considered ideal cell sources for regenerating neurons.Methods: We selected and tested different combinations of the small molecules for inducing the conversion of human and mouse astrocytes into neurons. Microscopic imaging and immunocytochemistry analyses were used to characterize the morphology and phenotype of the induced neurons while RT-q PCR was utilized to analyze changes in gene expression. In addition, whole-cell patch-clamp recordings were measured to examine the electrophysiological properties of induced neurons.Results: The results showed that human astrocytes could be rapidly and efficiently converted into motor neuronlike cells by treatment with defined small molecules, with a yield of over 85% motor neuron-like cells attained. The induced motor neuron-like cells expressed the pan-neuronal markers TUJ1, MAP2, Neu N, and Synapsin 1 and motor neuron markers HB9, ISL1, CHAT, and VACh T. During the conversion process, the cells did not pass through a proliferative neural progenitor cell intermediate. The induced motor neurons were functional, showing the electrophysiological properties of neurons. The same chemical cocktail could induce spinal cord astrocytes from an amyotrophic lateral sclerosis mouse model carrying a SOD1 mutation to become motor neuron-like cells that exhibited a decrease in cell survival and an increase in oxidative stress compared to that observed in wild-type MNs derived from healthy mice. Moreover, the chemical induction reduced oxidative stress in the mutant astrocytes.Conclusions: The results of the present study demonstrated the feasibility of chemically converting human and mouse astrocytes into motor neuron-like cells that are useful for neurodegenerative disease modeling and regenerative medicine.

Direct conversion of human fibroblasts into dopaminergic neuron-like cells using small molecules and protein factors

Background:Generation of neurons is essential in cell replacement therapy for neurodegenerative disorders like Parkinson’s disease.Several studies have reported the generation of dopaminergic(DA)neurons from mouse and human fibroblasts by ectopic expression of transcription factors,in which genetic manipulation is associated with potential risks.Methods:The small molecules and protein factors were selected based on their function to directly induce human fetal lung IMR-90 fibroblasts into DA neuron-like cells.Microscopical,immunocytochemical,and RT-qPCR analyses were used to characterize the morphology,phenotype,and gene expression features of the induced cells.The wholecell patch-clamp recordings were exploited to measure the electrophysiological properties.Results:Human IMR-90 fibroblasts were rapidly converted into DA neuron-like cells after the chemical induction using small molecules and protein factors,with a yield of approximately 95%positive TUJ1-positive cells.The induced DA neuron-like cells were immunopositive for pan-neuronal markers MAP2,NEUN,and Synapsin 1 and DA markers TH,DDC,DAT,and NURR1.The chemical induction process did not involve a neural progenitor/stem cell intermediate stage.The induced neurons could fire single action potentials,which reflected partially the electrophysiological properties of neurons.Conclusions:We developed a chemical cocktail of small molecules and protein factors to convert human fibroblasts into DA neuron-like cells without passing through a neural progenitor/stem cell intermediate stage.The induced DA neuron-like cells from human fibroblasts might provide a cellular source for cell-based therapy of Parkinson’s disease in the future.

Superior resistance to alkali metal potassium of vanadium-based NH_(3)-SCR catalyst promoted by the solid superacid SO_(4)^(2-)-TiO_(2)

The significant decrease of acid sites caused by alkali metal poisoning is the major factor in the deactivation of commercial V_(2)O_(5)-WO_(3)/TiO_(2)NH_(3)-SCR catalysts.In this work,the solid superacid SO_(4)^(2-)-TiO_(2) modified by sulfate radicals,was selected as the catalyst support,which showed superior potassium resistance.The physicochemical properties and K-poisoning resistance of the V_(2)O_(5)-WO_(3)/SO_(4)^(2-)-TiO_(2)(VWSTi) catalyst were carried out by XRD,BET,H2-TPR,NH3-TPD,XPS,in situ DRIFTS and TG.The results pointed out that the introduction of SO_(4)^(2-)significantly increased the NH3-SCR catalytic activity at high temperatures,with an exceptionally high NO_(x) conversion over 90% between 275℃ and 500℃.When 0.5%(mass) K_(2)O was doped on the catalysts,the catalytic performance of the traditional V_(2)O_(5)-WO_(3)/TiO_(2)(VWTi) catalyst decreased significantly,while the VWSTi catalyst could still maintain a NOxconversion over 90%in the range of 300–500℃.The characterizations suggested that the support of SO_(4)^(2-)-TiO_(2) greatly increased the number of acidic sites,thereby enhancing the adsorption capacity of the reactant NH_(3).The results above demonstrated a potential approach to achieve superior potassium resistance for NH3-SCR catalysts using solid superacid.

Influence of pore structure on thermal stress distribution inside coal particles during primary fragmentation

Thermal stress is an important reason of coal particle primary fragmentation,during which the role of pore structure is ambiguous.Thermal stress induced fragmentation experiments were conducted with low volatile coal/char particles,and the results show that the fragmentation severity enhances with increasing porosity.Various porous thermal stress models were developed with finite element method,and the influences of the pore shape,size,position and porosity on the thermal stress were discussed.The maximum thermal stress inside particle increases with pore curvature,the pore position affects the thermal stress more significantly at the particle center and surface.The expectation of the maximum tensile thermal stress linearly increases with porosity,making the particles with higher porosity easier to fragment,contrary to the conclusion deduced from the devolatilization theory.The obtained results are valuable for the analysis of different thermal processes concerning the thermal stresses of the solid feedstocks.

Electrospun nanofibrous membranes meet antibacterial nanomaterials:From preparation strategies to biomedical applications

Electrospun nanofibrous membranes(eNFMs)have been extensively developed for bio-applications due to their structural and compositional similarity to the natural extracellular matrix.However,the emergence of antibiotic resistance in bacterial infections significantly impedes the further development and applications of eNFMs.The development of antibacterial nanomaterials substantially nourishes the engineering design of antibacterial eNFMs for combating bacterial infections without relying on antibiotics.Herein,a comprehensive review of diverse fabrication techniques for incorporating antibacterial nanomaterials into eNFMs is presented,encompassing an exhaustive introduction to various nanomaterials and their bactericidal mechanisms.Furthermore,the latest achievements and breakthroughs in the application of these antibacterial eNFMs in tissue regenerative therapy,mainly focusing on skin,bone,periodontal and tendon tissues regeneration and repair,are systematically summarized and discussed.In particular,for the treatment of skin infection wounds,we highlight the antibiotic-free antibacterial therapy strategies of antibacterial eNFMs,including(i)single model therapies such as metal ion therapy,chemodynamic therapy,photothermal therapy,and photodynamic therapy;and(ii)multimodel therapies involving arbitrary combinations of these single models.Additionally,the limitations,challenges and future opportunities of antibacterial eNFMs in biomedical applications are also discussed.We anticipate that this comprehensive review will provide novel insights for the design and utilization of antibacterial eNFMs in future research.

CO_(2) mineralization of carbide slag for the production of light calcium carbonates

The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).

Engineering an ultrathin amorphous TiO2 layer for boosting the weatherability of TiO2 pigment with high lightening power

TiO2 pigments are typically coated with inert layers to suppress the photocatalytic activity and improve the weatherability. However, the traditional inert layers have a lower refractive index compared to TiO2, and therefore reduce the lightening power of TiO2. In the present work, a uniform, amorphous, 2.9-nm-thick TiO2 protective layer was deposited onto the surface of anatase TiO2 pigments according to pulsed chemical vapor deposition at room temperature, with Ti Cl4 as titanium precursor. Amorphous TiO2 coating layers exhibited poor photocatalytic activity, leading to a boosted weatherability. Similarly, this coating method is also effective for TiO2 coating with amorphous SiO2 and SnO2 layers. However, the lightening power of amorphous TiO2 layer is higher than those of amorphous SiO2 and SnO2 layers. According to the measurements of photoluminescence lifetime, surface photocurrent density, charge-transfer resistance, and electron spin resonance spectroscopy, it is revealed that the amorphous layer can prevent the migration of photogenerated electrons and holes onto the surface, decreasing the densities of surface electron and hole, and thereby suppress the photocatalytic activity.

The quasi-activity coefficients of non-electrolytes in aqueous solution with organic ions and its application on the phase splitting behaviors prediction for CO_(2) absorption

CO_(2)capture with a low energy consumption is of important application significance for reducing CO_(2)emission.The phase-change absorbent developed in recent years shows its potential for low-energy CO_(2)capture.The unclear phase-splitting rule hinders the efficient development of CO_(2)phase-change absorbents.To predict phase-splitting behaviors of mono/poly-amine-organic solvent-water system with various concentrations,a quasi-activity coefficient was developed based on Debye&Mc Aulay equation and some Density function theory descriptors.Six models based on Debye&Mc Aulay equation were developed with different ion radius,descriptors or poly-amine-CO_(2)products.The phase-splitting boundary was drawn on the model with the best predictability.This quasi-activity coefficient would provide guidance for the phase-splitting systems development,especially for polyamines.

Novel neutrophil extracellular trap-related mechanisms in diabetic wounds inspire a promising treatment strategy with hypoxia-challenged small extracellular vesicles

Neutrophil extracellular traps(NETs)have been considered a significant unfavorable factor for wound healing in diabetes,but the mechanisms remain unclear.The therapeutic application of small extracellular vesicles(sEVs)derived from mesenchymal stem cells(MSCs)has received considerable attention for their properties.Hypoxic preconditioning is reported to enhance the therapeutic potential of MSC-derived sEVs in regenerative medicine.Therefore,the aim of this study is to illustrate the detailed mechanism of NETs in impairment of diabetic wound healing and develop a promising NET-targeting treatment based on hypoxic pretreated MSC-derived sEVs(Hypo-sEVs).Excessive NETs were found in diabetic wounds and in high glucose(HG)-induced neutrophils.Further research showed that high concentration of NETs impaired the function of fibroblasts through activating endoplasmic reticulum(ER)stress.Hypo-sEVs efficiently promoted diabetic wound healing and reduced the excessive NET formation by transferring miR-17-5p.Bioinformatic analysis and RNA interference experiment revealed that miR-17-5p in Hypo-sEVs obstructed the NET formation by targeting TLR4/ROS/MAPK pathway.Additionally,miR-17-5p overexpression decreased NET formation and overcame NET-induced impairment in fibroblasts,similar to the effects of Hypo-sEVs.Overall,we identify a previously unrecognized NET-related mechanism in diabetic wounds and provide a promising NET-targeting strategy for wound treatment.

Application of pulsed chemical vapor deposition on the SiO_(2)-coated TiO_(2) production within a rotary reactor at room temperature

Pulsed chemical vapor deposition(P-CVD)is a promising technology for the surface modification of TiO_(2) particles.For the scale-up application of P-CVD,a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work.The obtained SiO_(2)-coated TiO_(2) particles were characterized by various measures including high-resolution transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,etc.The results illustrated that the SiO_(2) films with a thickness of(3.7±0.7)nm were successfully deposited onto the surface of TiO_(2) particles.According to the dye degradation tests and acid solubility measurement,the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO_(2) particles.Zeta potential measurements showed that the SiO_(2)-coated TiO_(2) is possible to be stably dispersed in the pH range of 6.9–11.6.The coating process made the whiteness of TiO_(2) particles decreased slightly but still sufficient(97.3±0.1)for application.Furthermore,the properties of the TiO_(2) particles coated by PCVD were compared with the particles coated by traditional wet chemical deposition.It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance.The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO_(2)-coated TiO_(2) via P-CVD.

Flexible wearable sensors:An emerging platform for monitoring of bacterial infection in skin wounds

Persistent inflammatory responses often occur when bacteria and other microorganisms frequently invade and colonize open wounds and eventually result in the formation of chronic wounds.Therefore,achieving real-time detection of invasive bacteria accurately and promptly is essential for efficient wound management and accelerat-ing the healing process.Recently,flexible wearable sensors have garnered significant attention,especially those designed for monitoring real-time biophysical or biochemical signals in wound sites in a minimally invasive manner.They provide more precise and continuous monitoring data,making them as emerging tools for clinical diagnostics.In this review,we first discuss the species and community distribution of different types of bacteria in chronic wounds.Next,we introduce currently developed techniques for detecting bacteria at wound sites.Fol-lowing that,we discuss the recent progress and unresolved issues of various flexible wearable sensors in detecting bacteria at wound sites.We believe that this review can provide meaningful guidance for the development of flexible wearable sensors for bacteria detection.

Chemical conversion of human and mouse fibroblasts into motor neurons

Transplantation of motor neurons can provide long-term functional benefits in animal models of neurodegenerative motor neuron diseases such as amyotrophic lateral sclerosis and traumatic spinal cord injury. Although embryonic stem cells can differentiate into motor neurons, alternative sources of motor neurons may be controllable for disease modeling and transplantation. Here, we show that human and mouse fibroblasts can be efficiently and directly converted into motor neurons by a cocktail of five small molecules, without the involvement of the neural progenitor stage. The chemically-induced motor neurons display the distinct neuronal morphology and express motor neuron markers. Interestingly, when the same chemical compounds were soaked in beads and implanted in the hypodermis of the back skins of mice, surrounding cells begin to express motor neuron markers,indicating in vivo motor neuron reprogramming. Taken together, we provide an efficient approach for chemically converting human and mouse fibroblasts into motor neurons suitable for cell replacement therapy and neurodegenerative disease modeling.

Desmoglein 2(DSG2) Is A Receptor of Human Adenovirus Type 55 Causing Adult Severe Community-Acquired Pneumonia

Human adenovirus type 55(HAdV-B55) is a re-emergent acute respiratory disease pathogen that causes adult communityacquired pneumonia(CAP). Previous studies have shown that the receptor of HAdV-B14, which genome is highly similar with HAdV-B55, is human Desmoglein 2(DSG2). However, whether the receptor of HAdV-B55 is DSG2 is undetermined because there are three amino acid mutations in the fiber gene between HAdV-B14 and HAdV-B55. Here, firstly we found the 3T3 cells, a mouse embryo fibroblast rodent cell line which does not express human DSG2, were able to be infected by HAdV-B55 after transfected with pcDNA3.1-DSG2, while normal 3T3 cells were still unsusceptible to HAdV-B55 infection. Next, A549 cells with h DSG2 knock-down by siRNA were hard to be infected by HAdV-B3/-B14/-B55, while the control siRNA group was still able to be infected by all these types of HAdVs. Finally, immunofluorescence confocal microscopy indicated visually that Cy3-conjugated HAdV-B55 viruses entered A549 cells by binding to DSG2 protein.Therefore, DSG2 is a major receptor of HAdV-B55 causing adult CAP. Our finding is important for better understanding of interactions between adenoviruses and host cells and may shed light on the development of new drugs that can interfere with these processes as well as for the development of potent prophylactic vaccines.

Calcium silicate accelerates cutaneous wound healing with enhanced re-epithelialization through EGF/EGFR/ERK-mediated promotion of epidermal stem cell functions

Background:Human epidermal stem cells(hESCs)play an important role in re-epithelialization and thereby in facilitating wound healing,while an effective way to activate hESCs remains to be explored.Calcium silicate(CS)is a form of bioceramic that can alter cell behavior and promote tissue regeneration.Here,we have observed the effect of CS on hESCs and investigated its possible mechanism.Methods:Using a mouse full-thickness skin excision model,we explored the therapeutic effect of CS on wound healing and re-epithelialization.In vitro,hESCs were cultured with diluted CS ion extracts(CSIEs),and the proliferation,migration ability and stemness of hESCs were evaluated.The effects of CS on the epidermal growth factor(EGF),epidermal growth factor receptor(EGFR)and extracellular signal-related kinase(ERK)signaling pathway were also explored.Results:In vivo,CS accelerated wound healing and re-epithelialization.Immunohistochemistry demonstrated that CS upregulated cytokeratin 19 and integrinβ1 expression,indicating that CS improved hESCs stemness.In vitro studies confirmed that CS improved the biological function of hESCs.And the possible mechanism could be due to the activation of the EGF/EGFR/ERK signaling pathway.Conclusion:CS can promote re-epithelialization and improve the biological functions of hESCs via activating the EGF/EGFR/ERK signaling pathway.

Epidemiology and clinical characteristics of burns in China's Mainland from 2009 to 2018

Background:Burn injuries place a heavy burden on the global healthcare system.However,there is still a lack of nationwide studies on the epidemiological characteristics of burn patients in China's Mainland.The present study aims to accurately analyze the clinical characteristics of burn patients by collecting data in China's Mainland from 2009 to 2018,which will provide effective strategies for healthcare systems and the government in China's Mainland.Methods:Patients admitted for burn injuries to 196 hospitals in 31 provinces,autonomous regions and municipalities in China's Mainland from 2009 to 2018 were included.The data collected included sex,age,month distribution,etiology,region,clinical outcome,injury anatomical location,total burn surface area and mortality.SPSS 19.0 software was used to analyze the data.Results:From 2009 to 2018,the burn patients were 333,995(0.76%),which included 222,480(66.61%)males and 111,515(33.39%)females.From 2009 to 2018,the number of individuals admit-ted to hospitals for burns showed a downward trend year by year.The burn patients accounted for the highest proportion of inpatients in 0-10 years(38.10%),followed by 40-50 years(13.14%).The highest cure ratio of burn inpatients was in the 20-30 age group(31394,71.53%).Among 31 provinces,autonomous regions and municipalities,the province with the highest proportion of total inpatients caused by burns was Inner Mongolia(4.61%),followed by Zhejiang(3.17%),Hainan(2.88%)and Xinjiang(2.64%).Summer(29.16%)was the season with the highest incidence of burn patients admitted to hospitals,followed by spring(25.6%).Scalding(60.19%)was the most frequent kind of burn treated,followed by fire(20.45%).The patients had multiple burn sites(68.89%)most often,followed by burns on the lower limbs(10.91%).From 0%to 10%total body surface area(TBSA)accounted for the highest ratio(37.19%),followed by 90-100%TBSA(21.74%).Conclusions:The present study is the first to describe the associated situation and trends of burn patients in China's Mainland from 2009 to 2018.Our findings will serve as the latest clinical evidence for healthcare planning and prevention efforts in China and other countries.

Characteristics of Changchengian rifts in southern margin of North China Craton and its hydrocarbon geological conditions

The Meso-Neoproterozoic strata are wildly distributed in North China Craton(NCC),of which Changchengian strata are most widely developed.Taking Changchengian strata in south margin of NCC as the study object,and combined with comprehensive analysis of isotopic chronology and petrology,it can be concluded that the Xiong'er rift is a plume rift which responds to breakup of Columbia supercontinent.Seismic data shows that Changchengian rifts are developed in the Qinshui Basin and the southern part of Ordos Basin covered by Phanerozoic strata,respectively are large-scale graben rifts and half-graben rifts.Aero magnetic data indicates that a NE-trending rift is developed in the west of the Xiong'er rift,and the Qinshui Basin rift is the extension of the north branch of the Xiong'er rift.The filling process of Changchengian rifts can be divided into four stages:the early rifting stage developing thick andesitic volcanic rocks,the late rifting stage developing large suite of coarse clastic sedimentary rocks,the depression stage developing fine clastic rocks,and the epeiric sea stage developing carbonate rocks.The dark argillaceous rocks are developed in Cuizhuang Formation and Chenjiajian Formation during the depression stage,and the black shale in Cuizhuang Formation is the effective source rocks.The bitume is filled in fractures of dolomite in Luoyukou Formation,as well as dissolution pores and large caves in Longjiayuan Formation.The argillaceous sandstone and muddy limestone of Lower Cambrian is the effective cap rocks,which can form an potential accumulation assemblage of Changchengian strata with underlying source rocks of Cuizhuang Formation and reservoirs of Luoyu Group,and this assemblage may be still effective at present.

Enhanced carbon dioxide adsorption performance and kinetic study of K and Al co-doped Li4SiO4

Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 times and ～1.3 times higher than that of the pristine Li4SiO4 at 500 and 600℃, respectively. The kinetic study further indicated that the reaction rates of the lithium diffusion process is greatly improved by K and AI doping, and the lithium diffusion rate of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2 times higher than that of the pristine Li4SiO4 at 575-650 ℃. K and AI doping increases the adsorption capacity of Li4SiO4-based adsorbents, and widens its effective adsorption temperature range

Capacity of human umbilical cord-derived mesenchymal stem cells to differentiate into sweat gland-like cells:a preclinical study

Human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)possess various advantageous properties,including self-renewal,extended proliferation potential,multi-lineage differentiation potential and capacity for differentiating into sweat gland-like cells in certain conditions.However,little is known about the effect of clinical-grade culture conditions on these properties and on the differentiative potential of hUC-MSCs.In this study,we sought to investigate the properties of hUC-MSCs expanded with animal serum free culture media(ASFCM)in order to determine their potential for differentiation into sweat gland-like cells.We found that primary cultures of hUC-MSCs could be established with ASFCM.Moreover,cells cultured in ASFCM showed vigorous proliferation comparable to those of cells grown in classical culture conditions containing fetal bovine serum(FBS).Morphology of hUC-MSCs cultured in ASFCM was comparable to those of cells grown under classical culture conditions,and hUC-MSCs grown in both of the two culture conditions tested showed the typical antigen profile of MSCs—positive for CD29,CD44,CD90,and CD105,and negative for CD34 and CD45,as expected.Chromosomal aberration assay revealed that the cells were stable after long-term culture under both culture conditions.Like normal cultured MSCs,hUC-MSCs induced under ASFCM conditions exhibited expression of the same markers(CEA,CK14 and CK19)and developmental genes(EDA and EDAR)that are characteristic of normal sweat gland cells.Taken together,our findings indicate that the classical culture medium used to differentiate hUC-MSCs into sweat gland-like cells can be replaced safely by ASFCM for clinical purposes.

MiR146a-loaded engineered exosomes released from silk fibroin patch promote diabetic wound healing by targeting IRAK1

Unhealable diabetic wounds need to be addressed with the help of newer,more efficacious strategies.Exosomes combined with biomaterials for sustained delivery of therapeutic agents are expected to bring new hope for chronic wound treatment.Here,the engineered exosomes modified for efficiently loading miR146a and attaching to silk fibroin patch(SFP)were demonstrated to promote diabetic wound healing.Silk fibroin binding peptide(SFBP)was screened through phage display,and SFBP-Gluc-MS2(SGM)and pac-miR146a-pac fusion protein were constructed.The designed exosomes(SGM-Exos,miR146a-Exos,and SGM-miR146a-Exos)were isolated from the engineered placental mesenchymal stem cells(PMSCs)transduced with SGM or/and pac-miR146a-pac protein.Gluc signals indicated SGM-Exo@SFP markedly increased the binding rate and the stability of SGM-Exo.Moreover,the loading efficiency of miR146a in SGM-miR146a-Exos was ten-fold higher than that in miR146a-Exos.Superior to untreated,SGM-miR146a-Exo-only treated,and SFP-only treated groups,SGM-miR146a-Exo@SFP drived wound healing associated with less inflammation,collagen deposition,and neovascularization.The transcriptomics analysis suggested anti-inflammatory and regenerative effects with SGM-miR146a-Exo@SFP treatment.Here,we show efficient exosome@biomaterial-based miRNA delivery systems for regenerative medicine and tissue engineering.