Three-dimensionally printed polycaprolactone and ß-tricalcium phosphate scaffolds for bone tissue engineering: an in vitro study.

PURPOSE: The purpose of this study was to evaluate porcine bone marrow-derived progenitor cell (pBMPC) proliferation and penetration into a novel 3-dimensionally printed scaffold. MATERIALS AND METHODS: Four different tissue engineering scaffolds to evaluate pBMPC proliferation and penetration were examined. Scaffolds were fabricated from polycaprolactone (PCL) or the combination of ß-tricalcium phosphate (ß-TCP) and PCL (50:50), with 2 separate channel sizes (1 mm [small (S)] vs 2 mm [large (L)]). Scaffolds were fabricated into 20 × 20 × 7-mm blocks by use of a TheriForm machine (Integra Life Sciences, Akron, OH). Four groups of scaffolds were examined for pBMPC proliferation and penetration: group 1, ß-TCP/PCL S; group 2, ß-TCP/PCL L; group 3, PCL S; and group 4, PCL L. Nonparametric mean (Kruskal-Wallis) and multiple comparisons tests were used to compare the 4 groups. RESULTS: No shrinkage or deformation was noted in any of the scaffold groups after 2 weeks of culture. Mean surface cell counts ranged from 13.4 to 87.8 cells/0.57 mm(2), with group 1 (ß-TCP/PCL S) having statistically significantly higher counts than the other groups (P < .001). Mean interior cell counts ranged from 10.9 to 75.6 cells/0.57 mm(2), with group 1 having the greatest interior cell count (P < .001). Total collagen formation ranged from 0.2% to 86%, with group 1 having the highest collagen formation (P < .001). CONCLUSIONS: The 3-dimensionally printed scaffold (ß-TCP/PCL) with 1-mm channels showed greater cellular proliferation, penetration, and collagen formation after a 2-week in vitro culture than the other scaffolds evaluated. ß-TCP/PCL S scaffolds warrant further evaluation for bone tissue engineering in vivo.

A novel polymeric chlorhexidine delivery device for the treatment of periodontal disease.

An implantable, anti-microbial delivery device for the treatment of periodontal disease has been developed. In this polymer-based delivery system, the encapsulation efficiency, release characteristics, and bioactivity of anti-microbial agent were controlled by the complexation of the drug with cyclodextrins of differing lipophilicity. Microparticles of poly(dl-lactic-co-glycolic acid) (PLGA) containing chlorhexidine (Chx) free base, chlorhexidine digluconate (Chx-Dg) and their association or inclusion complex with methylated-beta-cyclodextrin (MBCD) and hydroxypropyl-beta-cyclodextrin (HPBCD) were prepared by single emulsion, solvent evaporation technique. It was observed that encapsulation efficiency and release of the chlorhexidine derivatives from the microparticles was a function of the lipophilicity of the cyclodextrin. Complexation of the poorly water soluble Chx with the more hydrophilic HPBCD resulted in 62% higher encapsulation efficiency and longer duration of sustained release over a 2-week period than complexation with the more lipophilic MBCD. In contrast, the complexation of the more water-soluble derivative of chlorhexidine, Chx-Dg, with the more lipophilic MBCD improved encapsulation efficiency by 12% and prolonged its release in comparison to both the free Chx-Dg and its complex with HPBCD. Furthermore, it was observed that the initial burst effect could be diminished by complexation with CD. Preliminary studies have shown that the chlorhexidine released from PLGA chips is biologically active against bacterial population that is relevant in periodontitis (P. gingivalis and B. forsythus) and a healthy inhibition zone is maintained in agar plate assay over a period of at least a 1-week. The PLGA/CD delivery system described in this paper may prove useful for the localized delivery of chlorhexidine salts and other anti-microbial agents in the treatment of periodontal disease where prolonged-controlled delivery is desired.