polycaprolactones due to the polar groups in their structures are able to be mixed with other nitrate esters and thus are presented as suitable binders. In the other hand, polyglycidyl nitrate with ONO2 groups is a high energetic polymer; however, it has not suitable mechanical properties. Consequently, it is possible to use the favorable mechanical properties of polycaprolactone and energetic properties of polyglycidyl nitrate by the synthesis of the PCL-PGN-PCL three-block copolymer. In this research, the PCL-PGN-PCL three-block copolymer was synthesized for the first time. Firstly, polyglycidyl nitrate as a monomer was synthesized using epichlorohydrin (60% total yield of the reaction). Then, polyglycidyl nitrate was synthesized by using this monomer (70% yield). Finally, the new PCL-PGN-PCL three-block copolymer was synthesized by ring opening polymerization of caprolactone as monomer and polyglycidyl nitrate (PGN) as a macro initiator in the presence of dibutyl tin laurate as catalyst. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were performed to investigate the thermal characteristics of this copolymer (Tg -45.2oC). In addition, there was one pick in the GPC chromatogram that proved the formation of PCL-PGN-PCL three-block copolymer. The PCL-PGN-PCL three-block copolymer was characterized by 1HNMR, 13CNMR and IR spectroscopy methods. In the last part, the synthesis process of the PCL-PGN-PCL three-block copolymer was optimized. The reaction conditions were optimized at 115oC for 19 hours using 1mol% of catalyst. Toluene was chosen as a solvent and the monomer was added gradually into the reaction media. The yield was 81%. Also, the molar ratio of monomer to initiator as 5: 1 showed the best molecular dispersity.

The cross-linked starch/polycaprolactone (SPCL10) and starch/polycaprolactone (SPCL12) blends were prepared, characterized and used as carbon source and biofilm support for biological nitrate removal. The results showed that SPCL10 and SPCL12 had similar performance on water absorption (about 21 %) and leaching capacity. FTIR spectra confirmed the cross-linking reaction between starch and PCL. SEM displayed a thermoplastic nature of SPCL10 and SPCL12. These blends could serve as solid carbon source and biofilm support for biological denitrification, and the acclimation time of microbial biofilm on the surfaces of SPCL10, SPCL12 and PCL were about 2 days, 2 days and 16 days, respectively. The average denitrification rates were 0.0216, 0.0154 and 0.0071 mg NO3-N/(g h) for SPCL10, SPCL12 and PCL, respectively, and the effluent NO2-N concentration was below 1 mg/L at all cases. The phenomenon of ammonia formation was observed, but ammonia concentration was below 0.5 mg/L.

Paclitaxel used to treat malignant tumors of cancer by controlling the release of the drug to the tumor cells at the exact time. polycaprolactone (PCL) as a semi-crystalline polyester with a glass transition temperature and low melting point used as matrix and cellulose for fibrous layer. This polymer is easily processed at low temperatures, but due to its crystalline nature and strong hydrophobicity, the degradation of PCL is very slow. In this article, the anticancer drug is loaded into single-layer and three-layer cellulose acetate/polycaprolactone nanofibers and the amount of drug uptake, release behavior and release kinetics of the nanofibers are investigated. The resulting nanofibers were fabricated by electrospinning and freeze-drying to evaluate drug release and biocompatibility. Then, Scanning Electron Microscopy (SEM) showed the approximate diameter and length of the nanofibers as 300-400 nm. Functional group and chemical bonds of nanofibers were detected by Fourier Transform InfraRed  (FT-IR) spectroscopy analysis. Results have shown that the maximum degradation for PCL/CA + 15% D/PCL scaffold is 53% and 43% for the same scaffold by electrospinning method. The percentage of inflation increases as the concentration of PCL/CA in the scaffold increases. For the 5-minute time period, the percentage of inflation ranges from 14.29% for the PCL/CA+5%/PCL sample to 29.77% for the PCL/CA+15%/PCL sample. Similarly, for the 30-minute time period, the percentage of inflation ranges from 20.51% to 34.65% for the respective samples. The obtained results show slow and continuous release of the drug in vitro at 37°C and pH = 5.8, which can be used as a drug carrier in targeted treatment systems for anticancer drugs.

3D printing of scaffolds at low temperatures is very promising for making artificial bone graft alternatives with more performance than traditional techniques. One of the most promising strategies in bone tissue engineering has focused on the development of biomimetic scaffolds. Ceramic-based scaffolds with osteogenic ability and mechanical properties are promising candidates for bone repair. The aim of this study was to adapt the flexibility and increasing the effect of inducing osteogenesis of polycaprolactone (PCL) scaffold prepared by fused deposition modeling (FDM) method, using the combination of Collagen (COL) as a natural polymer with synthetic polymer and to investigate the behavior of MG63 cells on it. on it. After preparing the scaffold, scanning electron microscope (SEM), energy dispersive X-ray (EDX) and ATR-FTIR spectroscopy were used. After 1, 7, 14 days, the ossification process of MG63 cells in different treatments was performed using alizarin red staining and alkaline phosphatase activity. The non-toxicity of scaffolds was also evaluated by MTT assay to ensure cell proliferation. From under a microscope, it was found that tissue engineering scaffolds distributed and connected almost rectangular pores evenly. The PCL/COL scaffold showed a significant difference in terms of viability compared to the polycaprolactone scaffold only in the differential medium (P ≤ 0. 0001). The results of evaluating ALP activity in PCL/COL scaffolds were significantly higher than uncoated PCL scaffolds and control (P ≤ 0. 0001). The results of this study showed that the use of PCL/COL scaffold can be considered a suitable medium for proliferation and differentiation of MG63 cells in bone tissue engineering. Therefore, the PCL/COL composite scaffold prepared by FDM printer can be widely used in bone tissue engineering due to the cell survival by COL.

Introduction: This study was conducted to compare the effect of nanofibrous polycaprolactone (PCL) and PCL/gelatin (PCL/Gel) on limbal epithelial stem cell (LESC) and its efficiency for transplantation in animal model. Methods: PCL and PCL/Gel with a mass ratio of 70: 30 and 50: 50 was fabricated by electrospinning method. Human LESCs were cultured on PCL and PCL/Gel scaffolds and the effect of each scaffold on LESC proliferation, attachment and corneal epithelial regeneration in an animal model was evaluated, considering ease of use of scaffold and final transparency of the cornea. Results: Our data showed that PCL was more suitable than PCL/Gel for LESCs adherence, induction of epithelial morphology and proliferation. Histopathologic analysis of corneal sections from transplanted animals showed that epithelium was regenerated almost similar in PCL and PCL/Gel groups; however, vascularization and inflammation were significantly lower in the group receiving PCL. Conclusion: The represented data indicated the priority of PCL to PCL/Gel for the LESC attachment, proliferation and final outcome in an animal model of alkaline injury. This finding might be promising for cell therapy of corneal diseases.

Osteomyelitis is caused by the local spread of an infected source adjacent to the infection following trauma, bone surgery or joint replacement. The present study aimed to evaluate the effect of vancomycin (Van)/polycaprolactone (PCL) nanocomposite in comparison with curcumin (Cur)/PCL on the healing of experimental osteomyelitis in tibia in rabbits. After induction of osteomyelitis forty adult male New Zealand white rabbits were randomly divided into four groups. Control group: The animals were considered as controls and no scaffolds were used. In PCL/Van group, the created bone defects were filled with the combination of PCL and Van. In PCL/Cur, the created bone defects were filled with the combination of PCL and Cur. polycaprolactone/Cur/Van group: The created bone defects were filled with the combination of PCL, Cur and Van. Bone samples were taken for histopathological evaluation on the 30th and 60th days. For radiological evaluations of the osteomyelitis, radiographs were prepared at time intervals zero (day of surgery), 15, 30, 45, and 60 days after surgery. In order to evaluate hematology, blood was taken on days 0 (day of surgery), 15, 30, 45, and 60. The results of the present study showed that Cur nanocomposite significantly improved the healing process of the rabbit tibia experimental osteomyelitis model compared to the control group. Also, the PCL/Cur/Van group showed the best healing results. In conclusion, PCL/Cur/Van nanocomposite scaffold showed positive effects on the healing process.