3D printing of silver-doped polycaprolactone-poly(propylene succinate) composite scaffolds for skin tissue engineering

Scaffold-based tissue engineering approaches have been commonly used for skin regeneration or wound healings caused by diseases or trauma. For an ideal complete healing process, scaffold structures need to meet the criteria of biocompatibility, biodegradability, and antimicrobial properties, as well as to provide geometrical necessities for the regeneration of damaged tissue. In this study, design, synthesis and characterization of a three dimensional (3D) printable copolymer based on polycaprolactone-block-poly(1,3-propylene succinate) (PCL-PPSu) including anti-microbial silver particles is presented. 3D printing of PCL-PPSu copolymers provided a lower processing temperature compared to neat PCL, hence, inclusion of temperature-sensitive bioactive reagents into the developed copolymer could be realized. In addition, 3D printed block copolymer showed an enhanced hydrolytic and enzymatic degradation behavior. Cell viability and cytotoxicity of the developed copolymer were evaluated by using human dermal fibroblast (HDF) cells. The addition of silver nitrate within the polymer matrix resulted in a significant decrease in the adhesion of different types of microorganisms on the scaffold without inducing any cytotoxicity on HDF cells in vitro. The results suggested that 3D printed PCL-PPSu scaffolds containing anti-microbial silver particles could be considered as a promising biomaterial for emerging skin regenerative therapies, in the light of its adaptability to 3D printing technology, low-processing temperature, enhanced degradation behavior and antimicrobial properties.</p

Lactose-modified DNA tile nanostructures as drug carriers

<p><b>Background:</b> DNA hybridization allows the preparation of nanoscale DNA structures with desired shape and size. DNA structures using simple base pairing can be used for the delivery of drug molecules into the cells. Since DNA carries multiple negative charges, their cellular uptake efficiency is low. Thus, the modification of the DNA structures with molecules that may enhance the cellular internalization may be an option.</p> <p><b>Objective:</b> The objective of this study is to construct DNA-based nanocarrier system and to investigate the cellular uptake of DNA tile with/without lactose modification.</p> <p><b>Methods:</b> Doxorubicin was intercalated to DNA tile and cellular uptake of drug-loaded DNA-based carrier with/without lactose modification was investigated <i>in vitro</i>. HeLa, BT-474, and MDA-MB-231 cancer cells were used for cellular uptake studies and cytotoxicity assays. Using fluorescence spectroscopy, flow cytometry, and confocal microscopy, cellular uptake behavior of DNA tile was investigated. The cytotoxicity of DNA tile structures was determined with WST-1 assay.</p> <p><b>Results:</b> The results show that modification with lactose effectively increases the intracellular uptake of doxorubicin loaded DNA tile structure by cancer cells compared with the unmodified DNA tile.</p> <p><b>Conclusion:</b> The findings of this study suggest that DNA-based nanostructures modified with carbohydrates can be used as suitable multifunctional nanocarriers with simple chemical modifications.</p

Thermally exfoliated graphene oxide reinforced fluorinated pentablock poly(l-lactide-co-ε-caprolactone) electrospun scaffolds: Insight into antimicrobial activity and biodegradation

Three-dimensional fluorinated pentablock poly(l-lactide-co-ε-caprolactone)-based scaffolds were successfully produced by the incorporation of thermally exfoliated graphene oxide (TEGO) as an antimicrobial agent with an electrospinning technique. In a ring-opening polymerization, the fluorinated groups in the middle of polymer backbone were attached with a perfluorinated reactive stabilizer having oxygen-carrying ability. The fiber diameter and its morphologies were optimized through changes in TEGO amount, voltage, polymer concentration, and solvent type to obtain an ideal scaffold structure. Instead of the widely used graphene oxide synthesized by Hummer's method, TEGO sheets having a low amount of oxygen produced by thermal expansion were integrated into the fiber structure to investigate the effect of the oxygen functional groups of TEGO sheets on the degradation and antimicrobial activity of the scaffolds. There was no antimicrobial activity in TEGO-reinforced scaffolds in the in vitro tests in contrast to the literature. This study confirmed that a low number of oxygen functional groups on the surface of TEGO restricted the antimicrobial activity of the fabricated composite scaffolds

3D printing of silver-doped polycaprolactone-poly(propylene succinate) composite scaffolds for skin tissue engineering

Scaffold-based tissue engineering approaches have been commonly used for skin regeneration or wound healings caused by diseases or trauma. For an ideal complete healing process, scaffold structures need to meet the criteria of biocompatibility, biodegradability, and antimicrobial properties, as well as to provide geometrical necessities for the regeneration of damaged tissue. In this study, design, synthesis and characterization of a three dimensional (3D) printable copolymer based on polycaprolactone-block-poly(1,3-propylene succinate) (PCL-PPSu) including anti-microbial silver particles is presented. 3D printing of PCL-PPSu copolymers provided a lower processing temperature compared to neat PCL, hence, inclusion of temperature-sensitive bioactive reagents into the developed copolymer could be realized. In addition, 3D printed block copolymer showed an enhanced hydrolytic and enzymatic degradation behavior. Cell viability and cytotoxicity of the developed copolymer were evaluated by using human dermal fibroblast (HDF) cells. The addition of silver nitrate within the polymer matrix resulted in a significant decrease in the adhesion of different types of microorganisms on the scaffold without inducing any cytotoxicity on HDF cells in vitro. The results suggested that 3D printed PCL-PPSu scaffolds containing anti-microbial silver particles could be considered as a promising biomaterial for emerging skin regenerative therapies, in the light of its adaptability to 3D printing technology, low-processing temperature, enhanced degradation behavior and antimicrobial properties