Engineered Nanotopography on the Microfibers of 3D-Printed PCL Scaffolds to Modulate Cellular Responses and Establish an In Vitro Tumor Model.

Scaffold-based three-dimensional (3D) cell culture systems have gained increased interest in cell biology, tissue engineering, and drug screening fields as a replacement of two-dimensional (2D) monolayer cell culture and as a way to provide biomimetic extracellular matrix environments. In this study, microscale fibrous scaffolds were fabricated via electrohydrodynamic printing, and nanoscale features were created on the fiber surface by simply leaching gliadin of poly(ε-caprolactone) (PCL)/gliadin composites in ethanol solution. The microstructure of the printed scaffolds could be precisely controlled by printing parameters, and the surface nanotopography of the printed fiber could be tuned by varying the PCL/gliadin ratios. By seeding mouse embryonic fibroblast (NIH/3T3) cells and human nonsmall cell lung cancer (A549) cells on the printed scaffolds, the cellular responses showed that the fiber nanotopography on printed scaffolds efficiently favored cell adhesion, migration, proliferation, and tissue formation. Quantitative analysis of the transcript expression levels of A549 cells seeded on nanoporous scaffolds further revealed the upregulation of integrin-ß1, focal adhesion kinase, Ki-67, E-cadherin, and epithelial growth factor receptors over what was observed in the cells grown on the pure PCL scaffold. Furthermore, a significant difference was found in the relevant biomarker expression on the developed scaffolds compared with that in the monolayer culture, demonstrating the potential of cancer cell-seeded scaffolds as 3D in vitro tumor models for cancer research and drug screening.

Zein Increases the Cytoaffinity and Biodegradability of Scaffolds 3D-Printed with Zein and Poly(ε-caprolactone) Composite Ink.

Electrohydrodynamic printing (EHDP) has attracted extensive interests as a powerful technology to fabricate micro- to nano-scale fibrous scaffolds in a custom-tailored manner for biomedical applications. A few synthetic biopolymer inks are applicable to this EHDP technology, but the fabricated scaffolds suffered from low mechanical strength, biocompatibility, and biodegradability. In this study, a series of poly(ε-caprolactone) (PCL)/zein composite inks were developed and their printability was examined on a solution-based EHDP system for scaffold fabrication. Multilayer grid scaffolds were manufactured by PCL, PCL/zein-10, and PCL/zein-20 inks, respectively and characterized. The mechanical strength of scaffolds printed by PCL/zein composite inks was remarkably enhanced in terms of Young's modulus and yield stress. The enzyme-accelerated in vitro degradation study demonstrated that zein-containing scaffolds exhibited dose-responsive improvement on the degradation rate as evidenced by surface morphological change of fibers. Moreover, the biocompatibility of PCL/zein scaffolds, tested on mice embryonic fibroblast (NIH/3T3) and human nonsmall lung cancer cell (H1299), manifested better cell affinity. Our findings suggest that scaffolds fabricated by the solution-based EHDP with PCL/zein composite inks can significantly improve Young's modulus, yield stress, biocompatibility, and biodegradability and have potential applications in drug delivery systems, 3D cell culture modeling, or tissue engineering.

[Geographic distribution and gene sequencing of Paragonimus westermani in some areas of Guangdong Province].

OBJECTIVE: To investigate the current distribution of Paragonimus westermani in Guangdong Province. METHOD: Snails and crabs collected from mountain streams in regional survey sites were dissected to detect cercarial and metacercarial infections of P. westermani. Domestic cats and dogs artificially infected with the collected metacercariae were also dissected to detect adult worms of P. westermani. The COI and ITS2 gene sequences of those adult worms were compared with those of known Paragonimus specimen deposited in the GenBank. RESULTS: All of the first intermediate hosts in five survey sites of Liangkou, Nankun, Mountain, Dadong, Muxi, Guowu, were identified as Semisulcospira libertina, whose cercariae infection rates were 0.33%, 0.15%, 0.058%, 0.10%, and 0.05%, respectively; the second intermediate hosts in above five sites were all identified as Sinopotamon denticulatum, whose metacercariae infection rates were 100%, 100%, 38.09%, 55.36%, and 65.26%, respectively. The numbers of metacercariae in the five sites were 79.4, 105.66, 9.16, 16.18, and 15.6 per positive crab, respectively, and 11.12, 7.87, 0.58, 0.69, and 0.85 per gram of crab, respectively. All the metacercariae were identical to those of P. westermani. Adult worms and eggs of P. westermani were found in both reservoir hosts of domestic cats and dogs infected artificially. By comparing the COI genes of five representative samples from each survey site with that of Paragonimus #AF219379.21, AF540958.1 from GenBank, we found out the homology to be 99%, 99%, 99%, 98%, and 99%, respectively. In addition, a comparison of the ITS2 gene sequences between the above five samples and Paragonimus #DQ836243.1, DQ351845.1, AB354217.1 from GenBank revealed 98%, 99%, 98%, 98%, and 98% gene homology, respectively. CONCLUSION: Two ultra-high and three high endemic areas of P. westermani are discovered in Guangdong Province. No obvious differences were found among the types of P. westermani in the above five endemic areas.