Stable-jet length controlling electrospun fiber radius: Model and experiment

Polymer ◽  
2019 ◽  
Vol 180 ◽  
pp. 121762 ◽  
Author(s):  
Sailing Lei ◽  
Zhenzhen Quan ◽  
Hongnan Zhang ◽  
Xiaohong Qin ◽  
Rongwu Wang ◽  
...  
1989 ◽  
Vol 62 (04) ◽  
pp. 1057-1061 ◽  
Author(s):  
Marcus E Carr ◽  
Patrick L Powers

SummaryThis study was performed to quantitate the impact of several glycosaminoglycans (GAG) on fibrin assembly and structure. Gel formation was monitored as the increase in optical density at 633 nm subsequent to thrombin (2 NIH u/ml) or atroxin (0.10 mg/ml) addition to solutions of buffered fibrinogen (1 mg/ml) or plasma. Gel absorbance was measured as a function of wavelength (400 to 800 nm) and gel fiber diameter and mass/length ratio (μ) were calculated. Chondroitin sulfate A (CSA)shortened the lag phase, enhanced the maximal rate of turbidity increase, and increased the final gel turbidity of fibrin gels formed by thrombin or atroxin. CSA (16 mg/ml) increased fiber μ from 1.3 to 3.1 × 1013 dalton/cm and fiber radius from 6.0 to 8.6 × 10-6 cm in thrombin-induced gels. μ increased from 0.7 to 2.7 × 1013 dalton/cm and fiber radius from 4 to 7.8 × 10-6 cm for atroxin-induced gels. Above 16 mg/ml, CSA caused fibrinogen precipitation in purified solutions but not in plasma. CSA inhibited thrombin-induced plasma clotting of plasma but effects in atroxin-mediated plasma gels paralleled those seen in purified solutions. Chondroitin sulfate B (CSB)-induced changes in fibrin were similar but slightly less dramatic than those seen with CSA. μ increased from 0.9 to 2.0 × 1013 dalton/cm for thrombin-induced fibrin gels and from 0.8 to 2.3 × 1013 dalton/cm for atroxininduced gels. Low molecular weight heparin (Mr = 5100) slowed fibrin assembly and reduced fiber size by 50% in thrombininduced gels. Changes in μ of atroxin-induced gels were much less pronounced (<20%). This study documents pronounced GAGinduced changes in fibrin structure which vary with GAG species and may mediate significant physiologic functions.


2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>


2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>


Author(s):  
Margaret O. Ilomuanya ◽  
Prosper S. Okafor ◽  
Joyce N. Amajuoyi ◽  
John C. Onyejekwe ◽  
Omotunde O. Okubanjo ◽  
...  

2021 ◽  
Vol 329 ◽  
pp. 115459
Author(s):  
Evelin Sipos ◽  
Akos Juhasz ◽  
Miklos Zrinyi

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Yuqiong Kang ◽  
Changjian Deng ◽  
Xinyi Liu ◽  
Zheng Liang ◽  
Tao Li ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nurul Dinah Kadir ◽  
Zheng Yang ◽  
Afizah Hassan ◽  
Vinitha Denslin ◽  
Eng Hin Lee

Abstract Background Secretome profiles of mesenchymal stem cells (MSCs) are reflective of their local microenvironments. These biologically active factors exert an impact on the surrounding cells, eliciting regenerative responses that create an opportunity for exploiting MSCs towards a cell-free therapy for cartilage regeneration. The conventional method of culturing MSCs on a tissue culture plate (TCP) does not provide the physiological microenvironment for optimum secretome production. In this study, we explored the potential of electrospun fiber sheets with specific orientation in influencing the MSC secretome production and its therapeutic value in repairing cartilage. Methods Conditioned media (CM) were generated from MSCs cultured either on TCP or electrospun fiber sheets of distinct aligned or random fiber orientation. The paracrine potential of CM in affecting chondrogenic differentiation, migration, proliferation, inflammatory modulation, and survival of MSCs and chondrocytes was assessed. The involvement of FAK and ERK mechanotransduction pathways in modulating MSC secretome were also investigated. Results We showed that conditioned media of MSCs cultured on electrospun fiber sheets compared to that generated from TCP have improved secretome yield and profile, which enhanced the migration and proliferation of MSCs and chondrocytes, promoted MSC chondrogenesis, mitigated inflammation in both MSCs and chondrocytes, as well as protected chondrocytes from apoptosis. Amongst the fiber sheet-generated CM, aligned fiber-generated CM (ACM) was better at promoting cell proliferation and augmenting MSC chondrogenesis, while randomly oriented fiber-generated CM (RCM) was more efficient in mitigating the inflammation assault. FAK and ERK signalings were shown to participate in the modulation of MSC morphology and its secretome production. Conclusions This study demonstrates topographical-dependent MSC paracrine activities and the potential of employing electrospun fiber sheets to improve the MSC secretome for cartilage regeneration.


2021 ◽  
Vol 1948 (1) ◽  
pp. 012195
Author(s):  
Yuan Bo ◽  
He Xianyun ◽  
Zhang Tao

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