Biophysical Regulation of Cell Behavior-Cross Talk between Substrate Stiffness and Nanotopography

The stiffness and nanotopographical characteristics of the extracellular matrix （ECM） influence numerous developmental, physiological, and pathological processes in vivo. These biophysical cues have therefore been applied to modulate almost all aspects of cell behavior, from cell adhesion and spreading to proliferation and differentiation. Delineation of the biophysical modulation of cell behavior is critical to the rational design of new biomaterials, implants, and medical devices. The effects of stiffness and topographical cues on cell behavior have previously been reviewed, respectively; however, the interwoven effects of stiffness and nanotopographical cues on cell behavior have not been well described, despite similarities in phenotypic manifestations. Herein, we first review the effects of substrate stiffness and nanotopography on cell behavior, and then focus on intracellular transmission of the biophysical signals from integrins to nucleus. Attempts are made to connect extracellular regulation of cell behavior with the biophysical cues. We then discuss the challenges in dissecting the biophysical regulation of cell behavior and in translating the mechanistic understanding of these cues to tissue engineering and regenerative medicine.

Study of Cell Behaviors on Anodized TiO_2 Nanotube Arrays with Coexisting Multi-Size Diameters

It has been revealed that the different morphologies of anodized TiO_2 nanotubes, especially nanotube diameters, triggered different cell behaviors. However, the influence of TiO_2 nanotubes with coexisting multi-size diameters on cell behaviors is seldom reported. In this work, coexisting four-diameter TiO_2 nanotube samples, namely,one single substrate with the integration of four different nanotube diameters(60, 150, 250, and 350 nm), were prepared by repeated anodization. The boundaries between two different diameter regions show well-organized structure without obvious difference in height. The adhesion behaviors of MC3T3-E1 cells on the coexisting fourdiameter TiO_2 nanotube arrays were investigated. The results exhibit a significant difference of cell density between smaller diameters(60 and 150 nm) and larger diameters(250 and 350 nm) within 24 h incubation with the coexistence of different diameters, which is totally different from that on the single-diameter TiO_2 nanotube arrays. The coexistence of four different diameters does not change greatly the cell morphologies compared with the singlediameter nanotubes. The findings in this work are expected to offer further understanding of the interaction between cells and materials.

Progress in Electrospun Fibers for Manipulating Cell Behaviors

The manipulation of cell behaviors is essential to maintaining cell functions,which plays a critical role in repairing and regenerating damaged tissue.To this end,a rich variety of tissue-engineered scaffolds have been designed and fabricated to serve as matrix for supporting cell growth and functionalization.Among others,scaffolds made of electrospun fibers showed great potential in regulating cell behaviors,mainly owing to their capability of replicating the dimension,composition,and function of the natural extracellular matrix.In particular,electrospun fibers provided both topological cues and biofunctions simply by adjusting the electrospinning parameters and/or post-treatment.In this review,we summarized the most recent applications and advances in electrospun nanofibers for manipulating cell behaviors.First,the engineering of the secondary structures of individual fibers and the construction of two-dimensional nanofiber mats and nanofiber-based,three-dimensional scaffolds were introduced.Then,the functionalization strategies,such as endowing the fibers with bioactive,physical,and chemical cues,were explored.Finally,the typical applications of electrospun fibers in controlling cell behaviors(i.e.,cell adhesion and proliferation,infiltration,migration,neurite outgrowth,stem cell differentiation,and cancer cell capture and killing)were demonstrated.Taken together,this review will provide valuable information to the specific design of nanofiber-based scaffolds and extend their use in controlling cell behaviors for the purpose of tissue repair and regeneration.

Characterization of recombinant humanized collagen type Ⅲ and its influence on cell behavior and phenotype

Collagen made a tremendous impact in the field of regenerative medicine as a bioactive material.For decades,collagen has been used not only as a scaffolding material but also as an active component in regulating cells'biological behavior and phenotype.However,animal-derived collagen as a major source suffered from problems of immunogenicity,risk of viral infection,and the unclear relationship between bioactive sequence and function.Recombinant humanized collagen(rhCol)provided alternatives for regenerative medicine with more controllable risks.However,the characterization of rhCol and the interaction between rhCol and cells still need further investigation,including cell behavior and phenotype.The current study preliminarily demonstrated that recombinant humanized collagen typeⅢ(rhColⅢ)conformed to the theoretical amino acid sequence and had an advanced structure resembling bovine collagen.Furthermore,rhColⅢcould facilitate basal biological behaviors of human skin fibroblasts,such as adhesion,proliferation and migration.rhColⅢwas beneficial for some extracellular matrix-expressing cell phenotypes.The study would shed light on the mechanism research of rhCol and cell interactions and further understanding of effectiveness in tissue regeneration.

SYNTHETIC HYDROGELS AS SCAFFOLDS FOR MANIPULATING ENDOTHELIUM CELL BEHAVIORS

Synthetic hydrogels can be used as scaffolds that not only favor endothelial cells （ECs） proliferation but also manipulate the behaviors and functions of the ECs. In this review paper, the effect of chemical structure, Young＇s modulus （E） and zeta potential （ζ） of synthetic hydrogel scaffolds on static cell behaviors, including cell morphology, proliferation, cytoskeleton structure and focal adhesion, and on dynamic cell behaviors, including migration velocity and morphology oscillation, as well as on EC function such as anti-platelet adhesion, are reported. It was found that negatively charged hydrogels, poly（2-acrylamido-2-methylpropanesulfonic sodium） （PNaAMPS） and poly（sodium p-styrene sulphonate） （PNaSS）, can directly promote cell proliferation, with no need of surface modifcation by any cell-adhesive proteins or peptides at the environment of serum-containing medium. In addition, the Young＇s modulus （E） and zeta potential （ζ） of hydrogel scaffolds are quantitatively tuned by copolymer hydrogels, poly（NaAMPS-co-DMAAm） and poly（NaSS-co-DMAAm）, in which the two kinds of negatively charged monomers NaAMPS and NaSS are copolymerized with neutral monomer, N,N-dimethylacrylamide （DMAAm）. It was found that the critical zeta potential of hydrogels manipulating EC morphology, proliferation, and motility is ζcritical= -20.83 mV and ζcritical = -14.0 mV for poly（NaAMPS-co-DMAAm） and poly（NaSS-co-DMAAm）, respectively. The above mentioned EC behaviors well correlate with the adsorption of fibronectin, a kind of cell-adhesive protein, on the hydrogel surfaces. Furthermore, adhered platelets on the EC monolayers cultured on the hydrogel scaffolds obviously decreases with an increase of the Young＇s modulus （E） of the hydrogels, especially when E 〉 60 kPa. Glycocalyx assay and gene expression of ECs demonstrate that the anti-platelet adhesion well correlates with the EC-specific glycocalyx. The above investigation suggests that understanding the relationship between physic-chemical properties of synthetic hydrogels and cell responses is essential to design optimal soft and wet scaffolds for tissue engineering. Keywords： Synthetic hydrogel; Scaffold; Endothelial cell; Cell behavior

Deciphering the impact of PEG antifouling layer on surface attached functional peptides in regulating cell behaviors

It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells.These functions were widely achieved by attaching functional peptides to the surface of biomaterials.It is well known that an antifouling layer can help reducing the nonspecific cell attachment.However,it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior.This highlight introduced the recent JACS paper from Prof.Liu and coworkers in addressing this question thoroughly.

Characterization of recombinant humanized collagen type III and its influence on cell behavior and phenotype

Collagen made a tremendous impact in the field of regenerative medicine as a bioactive material.For decades,collagen has been used not only as a scaffolding material but also as an active component in regulating cells’biological behavior and phenotype.However,animal-derived collagen as a major source suffered from problems of immunogenicity,risk of viral infection,and the unclear relationship between bioactive sequence and function.Recombinant humanized collagen(rhCol)provided alternatives for regenerative medicine with more controllable risks.However,the characterization of rhCol and the interaction between rhCol and cells still need further investigation,including cell behavior and phenotype.The current study preliminarily demonstrated that recombinant humanized collagen type III(rhCol III)conformed to the theoretical amino acid sequence and had an advanced structure resembling bovine collagen.Furthermore,rhCol III could facilitate basal biological behaviors of human skin fibroblasts,such as adhesion,proliferation and migration.rhCol III was beneficial for some extracellular matrix-expressing cell phenotypes.The study would shed light on the mechanism research of rhCol and cell interactions and further understanding of effectiveness in tissue regeneration.

Engineering topography: Effects on corneal cell behavior and integration into corneal tissue engineering

Cell-material interactions are important to tissue engineering.Inspired by the natural topographic structures on the extracellular matrix,a growing number of studies have integrated engineering topography into investigations of cell behavior on biomaterials.Engineering topography has a significant influence on cell behaviors.These cell-topography interactions play an important role in regenerative medicine and tissue engineering.Similarly,cell-topography interactions are important to corneal reconstruction and regeneration.In this review,we primarily summarized the effects of topographic cues on the behaviors of corneal cells,including cell morphology,adhesion,migration,and proliferation.Furthermore,the integration of engineering surface topography into corneal tissue engineering was also discussed.

Surface Patterning of Self-healing P(MMA/nBA)Copolymer for Dynamic Control Cell Behaviors

Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical,mechanical and biochemical properties.However,most works regulate cell behaviors under static conditions or by external factors.To control cell adhesion and proliferation with a dynamic and mechanical environment,we pattern the surface on self-healing copolymer P(MMA/nBA).The copolymer P(MMA/nBA)with the composition of 48/52(MMA/nBA)recovers nearly 100%of its original tensile strains after 86 h of recovery from deformation.The physical patterns on P(MMA/nBA)film are obtained over large areas and the size of the hole and the width of connecting bar are in line with the copper grid specifications.The patterned surface tends to be fiat after 12 h with almost 75%-80%recovery.Compared with cell incubation on polystyrene fiat and patterned surface of P(MMA/nBA)film without self-healing capability,the number and morphology of cells are well manipulated on the patterned surface of self-healing P(MMA/nBA)film.This approach provides a convenient method for dynamically regulating the cell behaviors on the surface of self-healing materials without chemical or biological modifications.

Effect of Mineralized Layer Topographies on Stem Cell Behavior in Microsphere Scaffold

Modifying substrates through mineralization is a popular way to improve the osteogenic performance. Screening of the best mineralization characteristics on specific substrates for stem cells is meaningful but not fully studied. In this paper, poly（lactic-co-glycolic acid）/hydroxyapatite （PLGA[HA, PH） microsphere scaffolds with superficial pores were fabricated by a low-temperature fusion method. After the mineralization in the 5x stimulated body fluid （SBF） for 0, 7, 12 and 24 h, four mineralized scaffolds （MPH-0, MPH-7, MPH-12 and MPH-24） with different apatite topographies were obtained. It was found that the surface of MPH-7 was evenly decorated with abundant micro-pores, MPH-12 with dense and plain apatite layer, and MPH-24 with small spherical bumps. The responses of mouse bone mesenchymal stem cells （mBMSCs） to the four scaffolds were further studied. The results showed that MPH-7 and MPH-24 had more obvious effects on mBMSCs attachment, proliferation and differentiation than MPH-0 and MPH- 12. This work indicated that to obtain the maximum improvement, the mineralization characteristics had to be carefully chosen. This was noteworthy in the chemical modification of surfaces to form the functionalized scaffolds for bone repair.

Continuous live imaging reveals a subtle pathological alteration with cell behaviors in congenital heart malformation

To form fully functional four-chambered structure,mammalian heart development undergoes a transient finger-shaped trabeculae,crucial for efficient contraction and exchange for gas and nutrient.Although its developmental origin and direct relevance to congenital heart disease has been studied extensively,the time-resolved cellular mechanism underlying hypotrabeculation remains elusive.Here,we employed in toto live imaging and reconstructed the holistic cell lineages and cellular behavior landscape of control and hypotrabeculed hearts of mouse embryos from E9.5 for up to 24 h.Compared to control,hypotrabeculation in ErbB2 mutants arose mainly through dual mechanisms:both reduced proliferation of trabecular cardiomyocytes from early cell fate segregation and markedly impaired oriented cell division and migration.Further examination of mosaic mutant hearts confirmed alterations in cellular behaviors in a cell autonomous manner.Thus,our work offers a framework for continuous live imaging and digital cell lineage analysis to better understand subtle pathological alterations in congenital heart disease.

Cell behaviors on surface of pure tantalum with nano-dimpled structure

Tantalum exhibits excellent biocompatibility and good chemical stability, which has been employed in dental and orthopedic applications.The local microenvironment of the surface of implants influence determines the surrounding cell responses.In this work, nano-dimpled structure on the surface of pure tantalum was fabricated by electrochemical anodization.The surface morphology of the nano-dimpled structure was observed, and the dimensions of the nano-dimpled structure were measured by scanning electron microscopy(SEM).The surface roughness of the sample with nano-dimpled structure was measured by atomic force microscopy(AFM).The results show that the diameter of nano-dimpled ranges from 40 to 180 nm, and the higher the applied voltage, the larger the diameter.Moreover, nano-dimpled structure has good hydrophilicity.In vitro results show that nano-dimpled structure can promote the adhesion and proliferation of mouse cranial anterior bone(MC-3T3-E1) cells.The filopodia of MC-3T3-E1 cells can be fully extended on this nano-dimpled structure.On the surface of the nano-dimpled structure with a dimple size of 40 nm, the cells have the longest aspect ratio.The small dimple size of the nanodimpled structure is beneficial to cell proliferation and osteogenic differentiation.

Research on Growth Behavior of Embryos for Bovine and Murine on Primary Murine Embryos Fibroblast Cell Feeder Layer

The difference in growth behavior between bovine embryos and murine embryos was studied on PMEF(primary murine embryos fibroblast)feeder layer. The results showed as follows: With embryos having attached, bovine embryonic trophoblast formed a transparent membranous structure covering on inner cell mass (ICM), however, murine embryonic trophoblast formed disc structure. Bovine embryos formed four kinds of ICM colonies with different morphology including the mass-like, the net-like, the stream-like and the

Combined acupuncture and HuangDiSan treatment affects behavior and synaptophysin levels in the hippocampus of senescence-accelerated mouse prone 8 after neural stem cell transplantation

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 （SAMP8） mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer’s disease model mice. Sanjiao acupuncture was used to stimulate Danzhong （CV17）, Zhongwan （CV12）,Qihai （CV6）, bilateral Xuehai （SP10） and bilateral Zusanli （ST36） 15 days before and after implantation of neural stem cells （5 × 10^5） into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica,was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone,learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

Effect of Optical Microcavity on Absorption Behavior of Homo-Tandem Organic Solar Cells

The optical microcavity effect of the homo-tandem solar cells is explored utilizing the transfer matrix method. Ultrathin silver can reduce the deadzone effect compared with graphene and PH1000, and leads to a factor of 1.07 enhancement for an electrical field in a metal microcavity. The enhancement is considered to be the fact that strong exciton-photon coupling occurs in the microcavity due to ultrathin Ag. On the basis of the optical enhancement effect, optical behaviors are manipulated by varying the microcavity length. It is confirmed that ultrathin silver can serve as an ideal interconnection layer as the active layer is ～ 150nm thick and the thickness ratio between front and rear active layers lies between 1：1 and 1：2.

The Electrochemical Impedance Behavior of the Living Cells Escherichia Coli

The semiconductive characteristics of clectron-transfrring proteins in living cells E coli was investigated by electrochemsical impedance spectroscopy(EIS). We found that the electrochemical impedance of living cells as a function of temprature followed the Arrhenius equation for semiconductors. This result shows a strong evidence to prove the semiconductive behavior of proteins

Canine Cutaneous Mast Cell Tumor: Biologic Behavior and Its Correlation with Prognostic Indicators

Cutaneous mast cell tumor (MCT) shows a variable biological behavior in dogs and may present either as solitary masse that can be treated and cured with surgical removal or as a systemic metastatic and fatal disease. Histological grade, KIT pattern and proliferative index are typically prognostic factors in MCTs. In the present study, we have investigated correlation between clinical data (breed, age, gender, tumour location, tumor size, time before surgery, number of tumours, occurrence of metastasis and recurrence), cellular proliferation (Ki-67, mitotic index), intratumoural microvessel density (IMVD) and apoptotic index with the histological grade and KIT pattern. 28 tumors, from 20 dogs with cutaneous MCT were evaluated. There was association between histological grade, IMVD, tumor ulceration and number of tumors. A significant increase of Ki-67 expression and mitotic index was observed in MCTs with cytoplasmic KIT staining pattern. Patnaik histological grade system was related to mitotic index. Histological grade in canine cutaneous MCT should not be assessed as the only prognostic factor, but associated with KIT pattern, IMDV, cellular proliferation, presence of tumour ulceration, number of tumours, recurrences and metastases.

Effect of TiH_2 on preparation of closed-cell aluminum foam and its compressive behavior

The vesicant problem during the process of preparing closed-cell aluminum foam by molten body transitional foaming process was discussed and the effect of granularity and addition of TiH2on porosity of closed-cell aluminum foam was investigated. The static compressive behavior of closed-cell aluminum foam and the influence of porosity on static compressive property of closed-cell aluminum foam were researched as well. The results show that with increasing granularity of TiH2,the porosity of closed-cell aluminum foam firstly increases and then decreases gradually, the granularity should be controlled in the range of 38-74μm which can result in higher porosity. The porosity of closed-cell aluminum foam increases with the increasing addition of TiH2, and the addition of TiH2 should be controlled from 1.5% to 2.5% which can result in homogeneous cell and moderate strength of closed-cell aluminum foam. The compressive process of closed-cell aluminum foam obviously displays linear elastic phase, plastic collapse phase, and densification phase, and the compressive strength grows with decreasing porosity.

miR-27a通过TLR4/NF-κB信号通路对类风湿关节炎滑膜细胞生物学行为的影响

目的:探讨miR-27a通过Toll样受体(TLR)4/NF-κB信号通路对类风湿关节炎(RA)滑膜细胞生物学行为的影响。方法:选择行膝关节置换术的30例RA患者(RA组)和同期因创伤急诊截肢的18例患者(对照组)的滑膜组织,采用qRT-PCR法检测miR-27a的表达。将RA成纤维样滑膜细胞MH7A分为4组:空白对照组,不进行任何处理;TNF-α组,加入终浓度为20μg/L的TNF-α处理24 h;TNF-α+miR-NC组,加入终浓度为20μg/L的TNF-α处理后转染miR-NC;TNF-α+miR-27a mimic组,加入终浓度为20μg/L的TNF-α处理后转染miR-27a mimic,采用qRT-PCR法检测组织或细胞中miR-27a的表达量,CCK-8法检测细胞增殖情况,克隆形成实验检测细胞克隆形成能力,Transwell法检测细胞侵袭和迁移能力,Annexin V/PI双染法检测细胞凋亡情况,双荧光素酶报告实验验证TLR4 mRNA与miR-27a的靶向关系,Western blot法检测细胞中TLR4、NF-κB、磷酸化TLR4(p-TLR4)和磷酸化NF-κB(p-NF-κB)蛋白的表达情况。结果:对照组和RA组滑膜组织中miR-27a的表达量分别为(1.00±0.08)和(0.36±0.05),RA组低于对照组(P<0.001)。与空白对照组比较,TNF-α组和TNF-α+miR-NC组细胞中miR-27a表达量下降,TNF-α+miR-27a mimic组miR-27a表达量升高;与TNF-α组和TNF-α+miR-NC组比较,TNF-α+miR-27a mimic组细胞中miR-27a表达量升高(P<0.05)。与空白对照组比较,TNF-α组和TNF-α+miR-NC组细胞增殖、克隆形成、侵袭和迁移能力增强,细胞凋亡率降低;与TNF-α组和TNF-α+miR-NC组比较,TNF-α+miR-27a mimic组细胞增殖、克隆形成、侵袭和迁移能力减弱,细胞凋亡率升高(P<0.05)。双荧光素酶报告实验证实TLR4是miR-27a的靶基因。与空白对照组比较,TNF-α组和TNF-α+miR-NC组p-TLR4/TLR4、p-NF-κB/NF-κB升高;与TNF-α组和TNF-α+miR-NC组比较,TNF-α+miR-27a mimics组p-TLR4/TLR4、p-NF-κB/NF-κB降低(P<0.05)。结论:miR-27a可能通过抑制TLR4/NF-κB信号通路,降低RA成纤维样滑膜细胞的增殖、侵袭和迁移能力,促进其凋亡。

Biological behaviors of two novel syngeneic human osteosarcoma cell lines

Objective To characterize and compare the different biological behaviors of two novel human osteosarcoma cell lines,Zos and Zos-M,established respectively from the primary site and the skip metastasis of an osteosarcoma patient.Methods Two