Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring

Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant challenges for IHB.Gelatin is the most suitable candidate for IHB since it is a collagen hydrolysate and a substantial part of the extracellular matrix found naturally in most tissues.This study used 3D printing ultrafine fiber networks with metamaterial design to embed into ultra-low elastic modulus hydrogel to create a novel gelatin-based conductive film(GCF)with mechanical programmability.The regulation of GCF nearly covers soft tissue mechanics,an elastic modulus from 20 to 420 kPa,and a Poisson’s ratio from-0.25 to 0.52.The negative Poisson’s ratio promotes conformality with soft tissues to improve the efficiency of biological interfaces.The GCF can monitor heartbeat signals and respiratory rate by determining cardiac deformation due to its high conformability.Notably,the gelatin characteristics of the biodegradable GCF enable the sensor to monitor and support tissue restoration.The GCF metamaterial design offers a unique idea for bioelectronics to develop implantable sensors that integrate monitoring and tissue repair and a customized method for endowing implanted sensors to be highly conformal with soft tissues.

3D printed grafts with gradient structures for organized vascular regeneration

Synthetic vascular grafts suitable for small-diameter arteries(<6 mm) are in great need.However,there are still no commercially available small-diameter vascular grafts(SDVGs) in clinical practice due to thrombosis and stenosis after in vivo implantation.When designing SDVGs,many studies emphasized reendothelization but ignored the importance of reconstruction of the smooth muscle layer(SML).To facilitate rapid SML regeneration,a high-resolution 3D printing method was used to create a novel bilayer SDVG with structures and mechanical properties mimicking natural arteries.Bioinspired by the collagen alignment of SML,the inner layer of the grafts had larger pore sizes and high porosity to accelerate the infiltration of cells and their circumferential alignment,which could facilitate SML reconstruction for compliance restoration and spontaneous endothelialization.The outer layer was designed to induce fibroblast recruitment by low porosity and minor pore size and provide SDVG with sufficient mechanical strength.One month after implantation,the arteries regenerated by 3D-printed grafts exhibited better pulsatility than electrospun grafts,with a compliance(8.9%) approaching that of natural arteries(11.36%) and significantly higher than that of electrospun ones(1.9%).The 3D-printed vascular demonstrated a three-layer structure more closely resembling natural arteries while electrospun grafts showed incomplete endothelium and immature SML.Our study shows the importance of SML reconstruction during vascular graft regeneration and provides an effective strategy to reconstruct blood vessels through 3D-printed structures rapidly.

Identification and verification of aging-related lncRNAs for prognosis prediction and immune microenvironment in patients with head and neck squamous carcinoma

Aging is highly associated with tumor formation and progression.However,little research has explored the association of aging-related lncRNAs(ARLs)with the prognosis and tumor immune microenvironment(TIME)of head and neck squamous cell carcinoma(HNSCC).RNA sequences and clinicopathological data of HNSCC patients and normal subjects were downloaded from The Cancer Genome Atlas.In the training group,we used Pearson correlation,univariate Cox regression,least absolute shrinkage/selection operator regression analyses,and multivariate Cox regression to build a prognostic model.In the test group,we evaluated the model.Multivariate Cox regression was done to screen out independent prognostic factors,with which we constructed a nomogram.Afterward,we demonstrated the predictive value of the risk scores based on the model and the nomogram using time-dependent receiver operating characteristics.Gene set enrichment analysis,immune correlation analysis,and half-maximal inhibitory concentration were also performed to reveal the different landscapes of TIME between risk groups and to predict immuno-and chemo-therapeutic responses.The most important LINC00861 in the model was examined in HNE1,CNE1,and CNE2 nasopharyngeal carcinoma cell lines and transfected into the cell lines CNE1 and CNE2 using the LINC00861-pcDNA3.1 construct plasmid.In addition,CCK-8,Edu,and SA-β-gal staining assays were conducted to test the biofunction of LINC00861 in the CNE1 and CNE2 cells.The signature based on nine ARLs has a good predictive value in survival time,immune infiltration,immune checkpoint expression,and sensitivity to multiple drugs.LINC00861 expression in CNE2 was significantly lower than in the HNE1 and CNE1 cells,and LINC00861 overexpression significantly inhibited the proliferation and increased the senescence of nasopharyngeal carcinoma cell lines.This work built and verified a new prognostic model for HNSCC based on ARLs and mapped the immune landscape in HNSCC.LINC00861 is a protective factor for the development of HNSCC.

月经周期中免疫球蛋白G N-糖基化的周期性变化

Immunoglobulin G(IgG)is the most abundant plasma glycoprotein and a prominent humoral immune mediator.Glycan composition affects the affinity of IgG to ligands and consequent immune responses.The modification of IgG N-glycosylation is considered to be one of the various mechanisms by which sex hormones modulate the immune system.Although the menstrual cycle is the central sex hormonerelated physiological process in most women of reproductive age,IgG N-glycosylation dynamics during the menstrual cycle have not yet been investigated.To fill this gap,we profiled the plasma IgG Nglycans of 70 healthy premenopausal women at 12 time points during their menstrual cycles(every 7 days for 3 months)using hydrophilic interaction ultra-performance liquid chromatography(HILIC-UPLC).We observed cyclic periodic changes in the N-glycosylation of IgG in association with the menstrual cycle phase and sex hormone concentration in plasma.On the integrated cohort level,the modeled average menstrual cycle effect on the abundance of IgG N-glycosylation traits was low for each trait,with the highest being 1.1%for agalactosylated N-glycans.However,intrapersonal changes were relatively high in some cases;for example,the largest difference between the minimum and maximum values during the menstrual cycle was up to 21%for sialylated N-glycans.Across all measurements,the menstrual cycle phase could explain up to 0.72%of the variation in the abundance of a single IgG glycosylation trait of monogalactosylation.In contrast,up to 99%of the variation in the abundance of digalactosylation could be attributed to interpersonal differences in IgG N-glycosylation.In conclusion,the average extent of changes in the IgG N-glycopattern that occur during the menstrual cycle is small;thus,the IgG N-glycoprofiling of women in large sample-size studies can be performed regardless of menstrual cycle phase.

Neuro-bone tissue engineering:emerging mechanisms,potential strategies,and current challenges

The skeleton is a highly innervated organ in which nerve fibers interact with various skeletal cells.Peripheral nerve endings release neurogenic factors and sense skeletal signals,which mediate bone metabolism and skeletal pain.In recent years,bone tissue engineering has increasingly focused on the effects of the nervous system on bone regeneration.Simultaneous regeneration of bone and nerves through the use of materials or by the enhancement of endogenous neurogenic repair signals has been proven to promote functional bone regeneration.Additionally,emerging information on the mechanisms of skeletal interoception and the central nervous system regulation of bone homeostasis provide an opportunity for advancing biomaterials.However,comprehensive reviews of this topic are lacking.Therefore,this review provides an overview of the relationship between nerves and bone regeneration,focusing on tissue engineering applications.We discuss novel regulatory mechanisms and explore innovative approaches based on nerve–bone interactions for bone regeneration.Finally,the challenges and future prospects of this field are briefly discussed.

Bioprinting of novel 3D tumor array chip for drug screening

Biomedical field has been seeking a feasible standard drug screening system consisting of 3D tumor model array for drug researching due to providing sufficient samples and simulating actual in vivo tumor growth situation,which is still a challenge to rapidly and uniformly establish though.Here,we propose a novel drug screening system,namely 3D tumor array chip with“layer cake”structure,for drug screening.Accurate gelatin methacryloyl hydrogel droplets(~0.1μL)containing tumor cells can be automatically deposited on demand with electrohydrodynamic 3D printing.Transparent conductive membrane is introduced as a chip basement for preventing charges accumulation during fabricating and convenient observing during screening.Culturing chambers formed by stainless steel and silicon interlayer is convenient to be assembled and recycled.As this chip is compatible with the existing 96-well culturing plate,the drug screening protocols could keep the same as convention.Important properties of this chip,namely printing stability,customizability,accuracy,microenvironment,tumor functionalization,are detailly examined.As a demonstration,it is applied for screening of epirubicin and paclitaxel with breast tumor cells to confirm the compatibility of the proposed screening system with the traditional screening methods.We believe this chip will potentially play a significant role in drug evaluation in the future.

Rapid assembling organ prototypes with controllable cell-laden multi-scale sheets

A native organ has heterogeneous structures, sirength, and cell components. It is a big challenge to fabricate organ prototypes with controllable shapes, strength, and cells. Herein, a hybrid method is developed to fabricate organ prototypes with controlled cell deposition by integrating extrusion-based 3D printing, electrospinning, and 3D bioprinting. Multi-scale sheets were first fabricated by 3D printing and electrospinning;then, all the sheets were assembled into organ prototypes by sol-gel react io n duri ng bioprinting. With this method, macroscale structures fabricated by 3D printing ensure the customized structures and provide mechanical support, nanoscale structures fabricated by electrospinning offer a favorable environment for cell growth, and different types of cells with controllable densities are deposited in accurate locations by bioprinting. The results show that L929 mouse fibroblasts encapsulated in the structures exhibited over 90% survival within 10 days and maintai ned a high proliferation rate. Furthermore, the cells grew in spherical shapes first and then migrated to the nano scale fibers showing stretched morphology. Additionally, a branched vascular structure was successfully fabricated using the presented method. Compared with other methods, this strategy offers an easy way to simultancously realize the shape control, nanolibrous structures, and cell accurate deposition, which will have potemidi applications in tissue cngineering.

Parameter optimization model in electrical discharge machining process

Electrical discharge machining (EDM) process, at present is still an experience process, wherein selected parameters are often far from the optimum, and at the same time selecting optimization parameters is costly and time consuming. In this paper, artificial neural network (ANN) and genetic algorithm (GA) are used together to establish the parameter optimization model. An ANN model which adapts Levenberg-Marquardt algorithm has been set up to represent the relationship between material removal rate (MRR) and input parameters, and GA is used to optimize parameters, so that optimization results are obtained. The model is shown to be effective, and MRR is improved using optimized machining parameters.

Sacrificial microgel‑laden bioink‑enabled 3D bioprinting of mesoscale pore networks

Three-dimensional(3D)bioprinting is a powerful approach that enables the fabrication of 3D tissue constructs that retain complex biological functions.However,the dense hydrogel networks that form after the gelation of bioinks often restrict the migration and proliferation of encapsulated cells.Herein,a sacrificial microgel-laden bioink strategy was designed for directly bioprinting constructs with mesoscale pore networks(MPNs)for enhancing nutrient delivery and cell growth.The sacrificial microgel-laden bioink,which contains cell/gelatin methacryloyl(GelMA)mixture and gelled gelatin microgel,is first thermo-crosslinked to fabricate temporary predesigned cell-laden constructs by extrusion bioprinting onto a cold platform.Then,the construct is permanently stabilized through photo-crosslinking of GelMA.The MPNs inside the printed constructs are formed after subsequent dissolution of the gelatin microgel.These MPNs allowed for effective oxygen/nutrient diffusion,facilitating the generation of bioactive tissues.Specifically,osteoblast and human umbilical vein endothelial cells encapsulated in the bioprinted large-scale constructs(≥1 cm)with MPNs showed enhanced bioactivity during culture.The 3D bioprinting strategy based on the sacrificial microgel-laden bioink provided a facile method to facilitate formation of complex tissue constructs with MPNs and set a foundation for future optimization of MPN-based tissue constructs with applications in diverse areas of tissue engineering.

Studies of the Genotoxicity of Glycidyl Methacrylate (GMA)

The following experiments were conducted to evaluate the genotoxic effects of GMA (glycidyl methacrylale) on mammalian and human cells.(1) Using the absorption spectrum shift method in vitro, we observed that the maximums of calf thymus DNA and GMA were shifted toward longer wavelengths (a change of more than 15nm) and the absorbance decreased after incubation at room temperature for 15min or more.The result indicates that binding of DNA and GMA had occurred.The binding force is strong, not affected by the addition of concentrated sodium chloride solution, and only slightly decreased by the addition of 8 M urea solution.Therefore the bond between DNA and GMA might be covalent.(2) In cell cultures, unscheduled DNA synthesis (UDS) in human and/or rat lymphocyte was induced and DNA semiconserva-tive replication was inhibited by GMA at concentrations of less than 5.2 mM.(3) Sperm abnormality tests and assays of UDS in germ cells of male mice were conducted to study the in vivo genotoxicity of GMA.The results revealed that GMA could damage DNA, increase sperm abnormality frequency, and reduce the number of sperm cells, 1990 Academic Press.Inc.

Angiotensin-(1–7)reducesα-synuclein aggregation by enhancing autophagic activity in Parkinson's disease

Abnormal accumulation ofα-synuclein contributes to the formation of Lewy bodies in the substantia nigra,which is considered the typical pathological hallmark of Parkinson's disease.Recent research indicates that angiotensin-(1-7)plays a crucial role in several neurodegenerative disorders,including Parkinson's disease,but the underlying mechanisms remain elusive.In this study,we used intraperitoneal administration of rotenone to male Sprague-Dawley rats for 4 weeks to establish a Parkinson's disease model.We investigated whether angiotensin-(1-7)is neuroprotective in this model by continuous administration of angiotensin-(1-7)into the right substantia nigra for 4 weeks.We found that angiotensin-(1-7)infusion relieved characteristic parkinsonian behaviors and reducedα-synuclein aggregation in the substantia nigra.Primary dopaminergic neurons were extracted from newborn Sprague-Dawley rat substantia nigras and treated with rotenone,angiotensin-(1-7),and/or the Mas receptor blocker A-779 for 24 hours.After binding to the Mas receptor,angiotensin-(1-7)attenuated apoptosis andα-synuclein aggregation in rotenone-treated cells.Primary dopaminergic neurons were also treated with angiotensin-(1-7)and/or the autophagy inhibitor 3-methyladenine for 24 hours.Angiotensin-(1-7)increasedα-synuclein removal and increased the autophagy of rotenone-treated cells.We conclude that angiotensin-(1-7)reducesα-synuclein aggregation by alleviating autophagy dysfunction in Parkinson's disease.Therefore,the angiotensin-(1-7)/Mas receptor axis plays an important role in the pathogenesis of Parkinson's disease and angiotensin-(1-7)has potential therapeutic value for Parkinson's disease.All experiments were approved by the Biological Research Ethics Committee of Nanjing First Hospital(approval No.DWSY-2000932)in January 2020.

Why choose 3D bioprinting? Part I: a brief introduction of 3D bioprinting for the beginners

Graphic abstract Concept of 3D bioprinting 3D printing,also called additive manufacturing,is a layerby-layer manufacturing method,and it has been implemented in a wide variety of areas.3D printing could be treated as the reverse process of potato cutting,automatically assembling the chips or slicing into a potato[1].When this simple idea is met with biomedical engineering,3D bioprinting is born.

铋剂四联10天疗法联合酪酸梭菌、聚普瑞锌治疗幽门螺杆菌感染的疗效分析

目的评价铋剂四联10 d疗法联合酪酸梭菌、聚普瑞锌治疗幽门螺杆菌(Hp)感染的疗效及安全性。方法选取2018年7月—2021年6月于湘雅常德医院就诊使用铋剂四联10 d疗法联合酪酸梭菌、聚普瑞锌治疗Hp感染的209例患者作为研究对象。患者采用艾司奥美拉唑镁肠溶片(20 mg)+阿莫西林胶囊(1 g)+克拉霉素(0.5 mg)+胶体酒石酸铋胶囊(220 mg)均2次/d,酪酸梭菌活菌片(350 mg)3次/d,疗程10 d。后续追加艾司奥美拉唑肠溶片(20 mg,1次/d)+酪酸梭菌活菌片(350 mg,3次/d)+聚普瑞锌颗粒(75 mg,2次/d),疗程14 d。结果符合方案集分析(PP)和意向性分析(ITT)的Hp根除成功率分别为97.4%(189/194)和90.4%(189/209),9例(4.4%)患者在治疗期间出现不良反应,但程度均较轻微,可自行缓解。结论铋剂四联10 d疗法联合酪酸梭菌、聚普瑞锌作为Hp感染的治疗方案,根除率高,安全可行,在缩短抗生素疗程的同时不仅增加患者的依从性,也减少细菌产生耐药性。

Research on dynamic response characteristics of CFRP/Al HC SPs subjected to high-velocity impact

CFRP/Al HC SPs(Carbon Fiber Reinforced Plastic/Aluminum Honeycomb Sandwich Panels)composite structures are widely used in the aerospace and many other fields due to their excellent performances. In order to reveal profoundly the dynamic response characteristics of CFRP/Al HC SPs composite structure under high-velocity impact loading, the experiments about aluminum honeycomb core and CFRP/Al HC SPs composite structure impacted by high-velocity projectiles have been performed by using a one-stage light gas gun loading and a high-speed camera systems, respectively. The whole physical process of collision is analyzed by using TEMA software which is provided by high-speed camera's manufacturer,and the pictures and related physical parameters of the projectile passing through the different layers at the key moments are extracted based on the set frame rate of the video. Meanwhile, the ABAQUS/Explicit module was used to conduct numerical simulation under the same conditions as the experiments, and extracting the pictures and related physical parameters during the projectile penetrating through aluminum honeycomb core and the sandwich panels at the different key moments. The results show that the durations of action for the projectile impacting the Al HC core and the CFRP/Al HC SPs at the velocity about 280 m/s were 86 μs and 240 μs in experiments, respectively, and the durations of action were 90.7μs and 236.2 μs at the same experimental conditions in numerical simulation, which were basically consistent comparing the experimental to simulated results. Moreover, more than 70% for the kinetic energy of the projectile consumed by the sandwich panels was attributed to the front panel and the aluminum honeycomb core during the entire impact process, and all these have verified the reliability of the numerical simulation.

Volume conduction energy transfer for implantable devices

A common model of power supply for implantable devices was established to study factors affecting volume conduction energy transfer. Electromagnetic and equivalent circuit models were constructed to study the effect of separation between the source electrode pairs on volume conduction energy transfer. In addition, the parameters of external signal including waveform, amplitude and frequency were analyzed. As the current amplitude did not lead to tissue injury and the current frequency did not cause nerve excitability, the recommended separation be- tween the source electrodes was 3 cm, the proposed waveform of signal source was sinusoidal wave and the opti- mal frequency was 200 KHz. In agar experiment and swine skin experiment, the current transfer efficiencies were 28.13% and 20.65%, respectively, and the energy transfer efficiencies were 9.86% and 6.90%, respectively. In conclusion, we can achieve optimal efficiency of energy transfer by appropriately setting the separation between the source electrode parameters of the signal source.

Projection-based 3D bioprinting for hydrogel scaffold manufacturing

Projection-based 3D bioprinting(PBP):a powerful method to fabricate 3D cellular structures Three-dimensional(3D)bioprinting has played an important role in tissue engineering and regenerative medicine areas over the past decade[1].Different from traditional cell cultures in Petri dishes,3D bioprinting can build bionic structures with a better potential to become artificial organ substitutes[2–4].With the development of photocurable biomaterials,the projection-based 3D printing method has been successfully applied in biological research[5,6].

立足广西对环境资源保护法律人才培养的思考

随着广西北部湾地区社会经济的全面发展,环境保护与经济发展的矛盾也成为了首要问题,培养具有应对新发展新问题能力的高等教育人才箭在弦上。立足于此背景,本文针对广西各民族地区、北部湾地区的环境保护类人才培养的实际情况,进行资源与环境类法律人才培养的特色探索,提出满足广西地区人才培养需要的教学观念和教学方式,以推动整体培养模式与时俱进,培养更符合时代发展的应用型人才。

崂山地区青山滑坡地质灾害发生机理及其危险性

针对崂山地区典型的青山滑坡地质灾害点,开展滑坡发育特征和地质环境调查,分析了与滑坡发生相关的地形地貌、水文地质、工程地质等条件。综合各因素分析得出青山滑坡地质灾害发生的机理为:稳定性差的边坡在人类工程活动和强降雨条件下,使原有的力学平衡状态遭到破坏,导致滑坡灾害的发生。进行了灾害体稳定性评价,结果显示其稳定性较差,再次发生灾害的概率大,危险性大。

Study on Lateral Aerodynamic Characteristics of Hypersonic Lifting-Configuration

To have a deep understanding of the lateral stability of hypersonic lifting-configurations, wind-tunnel tests of roll static and dynamic stability for typical hypersonic lifting-configurations are carried out. The results show the roll is static unstable in small angles; the roll dynamic test curves present obvious non-linearity characteristics, and the model vibrates violently even When the angle of attack is small, which may be provoked by the non-symmetry transition from the small transverse flow around the nose of model. Subsequent research adopts longitudinal trips to generate symmetry transition at the fore-body of the model. As a result, the lateral stability of the aircrafts is apparently improved. The results show that the lateral stability of hypersonic aircrafts is very weak, and the main reason for this is lateral perturbation of flow over the nose, among which asymmetric transition weighs the most. Adoption of longitudinal trips could spur fixed transition of lateral flow, reduce the transition asymmetry of lateral flow, and strengthen the lateral stability of hypersonic aircrafts at the same time.

Rapid and mass manufacturing of soft hydrogel microstructures for cell patterns assisted by 3D printing

Micro-/nano-patterns on hydrogels are widely used in cell patterning.However,manufacturing molds with traditional lithography is time-consuming and expensive.In addition,the excessive demolding force can easily damage patterns since biocompatible hydrogels are ultra-soft or brittle.Here,we presented a novel method for rapid and mass fabrication of cell patterns.High-precision three-dimensional(3D)printing was used to manufacture a mold with a resolution of 2µm,and the gelatin-based hydrogel was cured by thermal–photo-crosslinking so that the low-concentration and low-substitutionrate hydrogel could be demolded successfully.We found that pre-cooling before illumination made gelatin-based hydrogels resilient due to the partial regain of triple-helix structures.With this method,arbitrarily customized hydrogel patterns with a feature size of 6–80µm can be fabricated stably and at low cost.When cardiomyocytes were seeded on ultra-soft hydrogels with parallel groove structures,a consistent and spontaneous beating with 216 beats per minute(BPM)could be observed,approaching the natural beating rate of rat hearts(300 BPM).Overall,this work provides a general scheme for manufacturing cell patterns which has great potential for cell ethology and tissue repair.