Refine
Has Fulltext
- yes (14)
Is part of the Bibliography
- yes (14)
Document Type
- Journal article (14) (remove)
Language
- English (14) (remove)
Keywords
- hyaluronic acid (5)
- biofabrication (3)
- bioprinting (3)
- 3D printing (2)
- additive manufacturing (2)
- bioink (2)
- chondrogenic differentiation (2)
- dual-stage crosslinking (2)
- extracellular matrix (2)
- melt electrospinning writing (2)
- 3D model systems (1)
- ACPC (1)
- Ca\(^{2+}\)-Imaging (1)
- ECM (1)
- HEMA (1)
- MSC (1)
- Schiff base chemistry (1)
- adipose tissue (1)
- adipose-derived stromal cells (1)
- agarose (1)
- alginate (1)
- astrocytes (1)
- bending strength (1)
- breast cancer (1)
- breast cancer model (1)
- calcium phosphate cement (1)
- cartilage (1)
- chondroprogenitors (1)
- click chemistry (1)
- co-culture (1)
- composite material (1)
- cortical neurons (1)
- drop on demand (1)
- dual setting system (1)
- electrohydrodynamic (1)
- electrohydrodynamics (1)
- free radical polymerization (1)
- human neutrophil elastase (HNE) (1)
- hydrogel (1)
- hydrogel formation (1)
- hydrogels (1)
- hydroxyapatite (1)
- hypoxia (1)
- melanoma (1)
- melt electrowriting (1)
- mucin (1)
- oxidation (1)
- peptide immobilization (1)
- photopolymerization (1)
- plasticizers (1)
- poly(lactide-co-glycolide) (1)
- polycaprolactone (1)
- polyethylene glycol (1)
- polymeric matrix (1)
- pre-crosslinking (1)
- printability (1)
- rheology (1)
- shape fidelity (1)
- shear stress (1)
- sodium alginate (1)
- solution electrospinning (1)
- spheroids (1)
- tethering (1)
- thiol-ene (1)
- tissue engineering (1)
- transforming growth factor-beta 1 (1)
- tumor heterogeneity (1)
- zonal (1)
Institute
EU-Project number / Contract (GA) number
- 309962 (1)
Polymers sensitive to thermal degradation include poly(lactic-co-glycolic acid) (PLGA), which is not yet processed via melt electrowriting (MEW). After an initial period of instability where mean fiber diameters increase from 20.56 to 27.37 µm in 3.5 h, processing stabilizes through to 24 h. The jet speed, determined using critical translation speed measurements, also reduces slightly in this 3.5 h period from 500 to 433 mm min\(^{−1}\) but generally remains constant. Acetyl triethyl citrate (ATEC) as an additive decreases the glass transition temperature of PLGA from 49 to 4 °C, and the printed ATEC/PLGA fibers exhibits elastomeric behavior upon handling. Fiber bundles tested in cyclic mechanical testing display increased elasticity with increasing ATEC concentration. The processing temperature of PLGA also reduces from 165 to 143 °C with increase in ATEC concentration. This initial window of unstable direct writing seen with neat PLGA can also be impacted through the addition of 10-wt% ATEC, producing fiber diameters of 14.13 ± 1.69 µm for the first 3.5 h of heating. The investigation shows that the initial changes to the PLGA direct-writing outcomes seen in the first 3.5 h are temporary and that longer times result in a more stable MEW process.
The Multiweek Thermal Stability of Medical-Grade Poly(ε-caprolactone) During Melt Electrowriting
(2022)
Melt electrowriting (MEW) is a high-resolution additive manufacturing technology that places unique constraints on the processing of thermally degradable polymers. With a single nozzle, MEW operates at low throughput and in this study, medical-grade poly(ε-caprolactone) (PCL) is heated for 25 d at three different temperatures (75, 85, and 95 °C), collecting daily samples. There is an initial increase in the fiber diameter and decrease in the jet speed over the first 5 d, then the MEW process remains stable for the 75 and 85 °C groups. When the collector speed is fixed to a value at least 10% above the jet speed, the diameter remains constant for 25 d at 75 °C and only increases with time for 85 and 95 °C. Fiber fusion at increased layer height is observed for 85 and 95 °C, while the surface morphology of single fibers remain similar for all temperatures. The properties of the prints are assessed with no observable changes in the degree of crystallinity or the Young's modulus, while the yield strength decreases in later phases only for 95 °C. After the initial 5-d period, the MEW processing of PCL at 75 °C is extraordinarily stable with overall fiber diameters averaging 13.5 ± 1.0 µm over the entire 25-d period.
Mucin, a high molecular mass hydrophilic glycoprotein, is the main component of mucus that coats every wet epithelium in animals. It is thus intrinsically biocompatible, and with its protein backbone and the o-glycosidic bound oligosaccharides, it contains a plethora of functional groups which can be used for further chemical modifications. Here, chain-growth and step-growth (thiol-ene) free-radical cross-linked hydrogels prepared from commercially available pig gastric mucin (PGM) are introduced and compared as cost-efficient and easily accessible alternative to the more broadly applied bovine submaxillary gland mucin. For this, PGM is functionalized with photoreactive acrylate groups or allyl ether moieties, respectively. Whereas homopolymerization of acrylate-functionalized polymers is performed, for thiol-ene cross-linking, the allyl-ether-functionalized PGM is cross-linked with thiol-functionalized hyaluronic acid. Morphology, mechanical properties, and cell compatibility of both kinds of PGM hydrogels are characterized and compared. Furthermore, the biocompatibility of these hydrogels can be evaluated in cell culture experiments.
Biointerface engineering is a wide-spread strategy to improve the healing process and subsequent tissue integration of biomaterials. Especially the integration of specific peptides is one promising strategy to promote the regenerative capacity of implants and 3D scaffolds. In vivo, these tailored interfaces are, however, first confronted with the innate immune response. Neutrophils are cells with pronounced proteolytic potential and the first recruited immune cells at the implant site; nonetheless, they have so far been underappreciated in the design of biomaterial interfaces. Herein, an in vitro approach is introduced to model and analyze the neutrophil interaction with bioactivated materials at the example of nano-bioinspired electrospun surfaces that reveals the vulnerability of a given biointerface design to the contact with neutrophils. A sacrificial, transient hydrogel coating that demonstrates optimal protection for peptide-modified surfaces and thus alleviates the immediate cleavage by neutrophil elastase is further introduced.