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1.
Evran E. Ural Victoria Toomajian Ehsanul Hoque Apu Mladen Veletic Ilangko Balasingham Nureddin Ashammakhi Masamitsu Kanada Christopher H. Contag 《International journal of molecular sciences》2021,22(9)
Extracellular vesicles (EVs) are cell-derived nanostructures that mediate intercellular communication by delivering complex signals in normal tissues and cancer. The cellular coordination required for tumor development and maintenance is mediated, in part, through EV transport of molecular cargo to resident and distant cells. Most studies on EV-mediated signaling have been performed in two-dimensional (2D) monolayer cell cultures, largely because of their simplicity and high-throughput screening capacity. Three-dimensional (3D) cell cultures can be used to study cell-to-cell and cell-to-matrix interactions, enabling the study of EV-mediated cellular communication. 3D cultures may best model the role of EVs in formation of the tumor microenvironment (TME) and cancer cell-stromal interactions that sustain tumor growth. In this review, we discuss EV biology in 3D culture correlates of the TME. This includes EV communication between cell types of the TME, differences in EV biogenesis and signaling associated with differing scaffold choices and in scaffold-free 3D cultures and cultivation of the premetastatic niche. An understanding of EV biogenesis and signaling within a 3D TME will improve culture correlates of oncogenesis, enable molecular control of the TME and aid development of drug delivery tools based on EV-mediated signaling. 相似文献
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Pihlajamäki H Mäkelä EA Ashammakhi N Viljanen J Pätiälä H Rokkanen P Pohjonen T Törmälä P Joukainen A 《Journal of materials science. Materials in medicine》2002,13(4):389-395
Drawn self-reinforced polyglycolide (SR-PGA) rods, Ø 2 mm and 26 mm long, were implanted in the dorsal subcutaneus tissue of 16 rats. Osteotomies of the distal femur were fixed with SR-PGA rods (2 mm by 15 mm) in another 38 rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were also performed. At three weeks the flexural strength of the rods was 50% of the initial value, and the flexural modulus was 46% of the initial value. Five osteotomy specimens had to be excluded due to dislocation or non-union. One of the 33 evaluated osteotomy specimens showed signs of postoperative infection. Thirty-two osteotomies healed uneventfully. No gross signs of inflammatory or foreign-body reaction were observed. The amount of osteoid surface and active osteoid formation surface reached their highest value in the histomorphometrical analysis at 24 weeks. The present investigation demonstrated that the mechanical strength and fixation properties of the drawn SR-PGA rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on the successful application of drawn SR-PGA rods for fixation of cancellous bone osteotomies. 相似文献
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Viitanen P Suokas E Törmälä P Ashammakhi N 《Journal of materials science. Materials in medicine》2006,17(12):1267-1274
Due to inflammatory reactions complicating bioabsorbable devices, the aim of this study was to develop and characterize bioabsorbable
implants with anti-inflammatory drug releasing properties. Polylactide-co- glycolide (PLGA) 80/20 was compounded with diclofenac
sodium (DS) to produce rods. Thermal properties were analyzed using differential scanning calorimetry (DSC). Inherent viscosity
(ηinh) was measured to evaluate the drug effect on the extrude polymer. Drug release measurements were performed using UV-spectrophotometer.
Five parallel samples from each type of rods were examined, first at 6 hour intervals, then on daily basis, and later twice
a week. DS was released in 110 days from thinner rods and in 150 days from thicker rods. Drug release comprised a starting
peak, slow release phase, then a high release phase, and a burst release phase. DSC analysis showed that DS containing rods
had crystallinity in their structure. In conclusions, it is feasible to combine PLGA 80/20 and DS by using melt extrusion.
Released DS concentrations reached local therapeutic levels, but the release profile was complex and therapeutic levels were
not reached all the time. 相似文献
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Tiainen J Soini Y Suokas E Veiranto M Törmälä P Waris T Ashammakhi N 《Journal of materials science. Materials in medicine》2006,17(12):1315-1322
The aim of this study was to assess tissue reactions to bioabsorbable self-reinforced ciprofloxacin-releasing polylactide/polyglycolide (SR-PLGA) 80/20 screws in rabbits' cranial bone. Two screws were implanted in each rabbit, one screw on either side of the sagittal suture (n = 28 rabbits). Animals were sacrificed after 2, 4, 8, 16, 24, 54 and 72 weeks, four animals per group. On histological examination the number of macrophages, giant cells, active osteoblasts and fibrous tissue layers were assessed and degradation of the screws was evaluated. At 2 weeks, the highest number of macrophages and giant cells were seen near the heads of the screws. After 4 and 8 weeks, the number of giant cells decreased but that of macrophages decreased from 16 weeks and on. Screws were surrounded by fibrous tissue capsule that progressively was growing in thickness by time. Active osteoblasts were seen around the shaft of the screws with the highest number seen at 4 weeks postoperatively. At 16 weeks, compact fragmentation of the screw heads was seen with macrophages seen inside the screw matrices. After 24 weeks, no polarization of the screws was seen. After one year, PLGA screws had been replaced by adipose tissue, fibrous tissue and "foamy macrophages" which had PLGA particles inside them. After 1(1/2) years, the amount of biomaterial remaining had decreased remarkably. The particles of biomaterial were inside "foamy macrophages." Ciprofloxacin-releasing SR-PLGA 80/20 screws elicited a mild inflammatory reaction but did not interfere with osteoblast activity. No complications were seen when implanted in cranial bone of rabbit. 相似文献
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Ali Tuncay Ozyilmaz Gul Ozyilmaz Ercan Yılmaz Nureddin Çolak 《Korean Journal of Chemical Engineering》2008,25(4):846-853
The electrochemical synthesis of poly(o-anisidine) (POA) was achieved on brass (CuZn) electrode by applying two scan rates
(50 and 20 mVs−1). The synthesized polymer films were strongly adherent and homogeneous in both cases. Their corrosion performance was investigated
by AC impedance spectroscopy (EIS) technique, anodic polarization plots and open circuit potential-time curves, in 3.5% NaCl
solution. It was clearly seen that poly(o-anisidine) films provided a significant physical protection for longer exposure
time. It was shown that polymer film coated at high scan rate (CuZn/POA-H) exhibited better barrier property against the attack
of corrosive agents when compared with polymer film obtained at low scan rate (CuZn/POA-L). It was found out that poly(o-anisidine)
film synthesized at high scan rate caused a significant increase in corrosion resistance by its catalytic behavior on formation
of protective oxide layers on the surface in longer time. 相似文献
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Tyler Hoffman Petar Antovski Peyton Tebon Chun Xu Nureddin Ashammakhi Samad Ahadian Leonardo Morsut Ali Khademhosseini 《Advanced functional materials》2020,30(26)
Tissue engineering approaches, with the goals of replacing or recovering damaged or diseased tissues, or of reconstituting tissues in vitro for disease modeling and drug development, have the potential to make significant contributions to medicine. Advances in stem cell biology, biomaterial synthesis and characterization, and microscale technologies have made engineered tissues a reality. However, the classic tools used to build tissues in the lab do not allow for complete control of cell behaviors. More recently, synthetic biology principles have developed robust and versatile approaches to program cells with artificial genetic circuits, where cell behavior and function can be manipulated. At the interface between synthetic biology and tissue engineering, there is space for a new area of investigation where material engineering and cellular engineering complement and sustain each other. In this progress report, synthetic biology principles and how they have been used to engineer cells with potential to dictate cell behavior and function in tissue constructs of the future are briefly described. It is believed that this research area still needs further exploration to fully exploit synthetic biology to make smart and functional cellular constructs for therapeutic and in vitro applications. 相似文献
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Nureddin Ashammakhi Ana Lopez Hernandez Bige Deniz Unluturk Sergio A. Quintero Natan Roberto de Barros Ehsanul Hoque Apu Abdullah Bin Shams Serge Ostrovidov Jinxing Li Christopher Contag Antoinette S. Gomes Miguel Holgado 《Advanced functional materials》2021,31(49):2104149
The ability to monitor diseases, therapies, and their effects on the body is a critical component of modern care and personalized medicine. Real time monitoring can be achieved by analyzing body fluids or by applying sensors on, or alternatively, inside the body. Implantable sensors, however, must be removed. Second removal procedures lead to further tissue damage, which can be a problem in tissues such as those of the central nervous system. The use of biodegradable sensors alleviates these problems since they do not require removal procedures. Recent advances in material science made it possible for all sensor components to be biodegradable. Small size and power of implants, and the limited selection of materials are the main constraints determining the capabilities of the biodegradable device. Thus, the design will be always a challenge exploring a trade-off among these parameters. Despite of the encouraging results illustrating that biodegradable sensors can be as accurate and reliable as commercially available nondegradable ones, biodegradable implantable sensors are still in their infancy. Significant advances made in this area are critically reviewed in this paper, and future prospects are highlighted. 相似文献
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Jixiang Zhu Xingwu Zhou Han‐Jun Kim Moyuan Qu Xing Jiang KangJu Lee Li Ren Qingzhi Wu Canran Wang Xunmin Zhu Peyton Tebon Shiming Zhang Junmin Lee Nureddin Ashammakhi Samad Ahadian Mehmet Remzi Dokmeci Zhen Gu Wujin Sun Ali Khademhosseini 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(16)
The extraction of interstitial fluid (ISF) from skin using microneedles (MNs) has attracted growing interest in recent years due to its potential for minimally invasive diagnostics and biosensors. ISF collection by absorption into a hydrogel MN patch is a promising way that requires the materials to have outstanding swelling ability. Here, a gelatin methacryloyl (GelMA) patch is developed with an 11 × 11 array of MNs for minimally invasive sampling of ISF. The properties of the patch can be tuned by altering the concentration of the GelMA prepolymer and the crosslinking time; patches are created with swelling ratios between 293% and 423% and compressive moduli between 3.34 MPa and 7.23 MPa. The optimized GelMA MN patch demonstrates efficient extraction of ISF. Furthermore, it efficiently and quantitatively detects glucose and vancomycin in ISF in an in vivo study. This minimally invasive approach of extracting ISF with a GelMA MN patch has the potential to complement blood sampling for the monitoring of target molecules from patients. 相似文献