Halili, A. N., Hasirci, N., and Hasirci, V. (2014). A multilayer tissue engineered meniscus substitute. Journal of Materials Science: Materials in Medicine, 25(4), 1195-1209. DOI: 10.1007/s10856-014-5145-0

Various methods have been tried to treat the main meniscus problem, meniscal tears, for which we believe tissue engineering could be a viable solution. In this study, a three dimensional, collagen-based meniscus substitute was prepared by tissue engineering using human fibrochondrocytes and a collagen based-scaffold. This construct was made with 3 different collagen-based foams interspaced with two electrospun nano/microfibrous mats. The top layer was made of collagen type I–chondroitin sulfate–hyaluronic acid (Coll–CS–HA), and the middle and the bottom layers were made of only collagen type I with different porosities and thus with different mechanical properties. The mats of aligned fibers were a blend of collagen type I and poly(L-lactic acid-co-glycolic acid) (PLGA). After seeding with human fibrochondrocytes, cell attachment, proliferation, and production of extracellular matrix and glucoseaminoglycan were studied. Cell seeding had a positive effect on the compressive properties of foams and the 3D construct. The 3D construct with all its 5 layers had better mechanical properties than the individual foams.

Eke, G., Kuzmina, A. M., Goreva, A. V., Shishatskaya, E. I., Hasirci, N., and Hasirci, V. (2014). In vitro and transdermal penetration of PHBV micro/nanoparticles. Journal of Materials Science: Materials in Medicine, 25(6), 1471-1481. DOI: 10.1007/s10856-014-5169-5

The purpose of this study was to develop micro and nano sized drug carriers from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and study the cell and skin penetration of these particles. PHBV micro/nanospheres were prepared by o/w emulsion method and were stained with a fluorescent dye, Nile Red. The particles were fractionated by centrifugation to produce different sized populations. Topography was studied by SEM and average particle size and its distribution were determined with particle sizer. Cell viability assay (MTT) was carried out using L929 fibroblastic cell line, and particle penetration into the cells were studied. Transdermal permeation of PHBV micro/nanospheres and tissue reaction were studied using a BALB/c mouse model. Skin response was evaluated histologically and amount of PHBV in skin was determined by gas chromatography-mass spectrometry. The average diameters of the PHBV micro/nanosphere batches were found to be 1.9 μm, 426 and 166 nm. Polydispersity indices showed that the size distribution of micro sized particles was broader than the smaller ones. In vitro studies showed that the cells had a normal growth trend. MTT showed no signs of particle toxicity. The 426 and 166 nm sized PHBV spheres were seen to penetrate the cell membrane. The histological sections revealed no adverse effects. In view of this data nano and micro sized PHBV particles appeared to have potential to serve as topical and transdermal drug delivery carriers for use on aged or damaged skin or in cases of skin diseases such as psoriasis, and may even be used in gene transfer to cells.