Design and manufacture of 3D-cylindrical scaffolds based on PLA/TPU/n-HA with the help of dual salt leaching technique suggested for use in cancellous bone tissue engineering.

A series of 3-D scaffolds based on polylactic acid (PLA) and thermoplastic polyurethane (TPU) as major phase and hydroxyapatite nanoparticles (n-HA) were prepared by using the dual leaching technique. Fourier-transform infrared spectroscopy analysis showed that almost the interactions between the constituent materials can be identified based on their functional groups. The results of thermogravimetric analysis were used to obtain the best time to prepare the samples without residual of any progen additives. The scanning electron macroscopy images clearly proved that the dual leaching technique is an effective method to prepare the appropriate morphology and also a very good dispersion and distribution for n-HA can be obtained. Dynamic contact angles showed that the presence of TPU in the PLA matrix has a positive effect on the hydrophilicity of the scaffolds. The bulk modulus (κ) values of S-PLA70TPU30H5 in dry and wet conditions were 321 and 212 Pa, respectively and the compressibility coefficient (ß) of pure samples was higher than that of other scaffolds, while among the nanocomposite samples, the compressibility coefficient of S-PLA70TPU30H5 and S-PLA50TPU50H5 samples in dry and wet conditions was higher than that of other samples. Biological tests such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay, cell adhesion, 4',6-diamidino-2-phenylindole (DAPI) analysis and alizarin red were also performed, and the results obtained for 3D scaffolds were good. In the DAPI analysis test, sample 3D-S-PLA70TPU30H5 showed good behavior, and also in the alizarin red test, the amount of minerals created in 3D-S-PLA50TPU50H5 was significant.

Dual leaching technique was used to prepare cylindrical scaffolds with high porosity.3D cylindrical scaffolds based on PLA/TPU/n-HA were proposed for use in cancellous bone.Bulk modulus and compressibility coefficient of 3D cylindrical scaffolds were obtained in wet and dry conditions.DAPI analysis showed the role of n-HA nanoparticles on cell growth in 3D cylindrical scaffolds.Alizarin red studies showed that sample PLA50TPU50H5 has more calcium content.

Sustained release of valproic acid loaded on chitosan nanoparticles within hybrid of alginate/chitosan hydrogel with/without stem cells in regeneration of spinal cord injury.

Hydrogels have been increasingly applied in tissue regeneration and drug delivery systems (DDS). In this study, the capacity of valproic acid (Val) encapsulated within hybrid of alginate (Alg)-chitosan (Cs) (Alg-Cs) hydrogel containing Cs nanoparticle (Npch) with/without human endometrial stem cells (hEnSC) was initially examined for regeneration of spinal cord injury (SCI). To evaluate the stability of the synthesized hydrogels zeta potential necessary measurements were made. Physicochemically, the developed hydrogels were evaluated using Fourier-transform infrared (FTIR) spectroscopy. The physical properties including degradation rate, swelling ability, and tunability of the synthesized hydrogels were studied. To evaluate the nerve regeneration ability of the synthesized hydrogels, 35 Sprague-Dawley rats were undergone SCI. The spinal cords were exposed using laminectomy in T9-T10 area and the hemi-section SCI model was made. The rats were then randomly divided into 5 groups (n = 7) including, Alg-Cs/Npch, Alg-Cs/Npch/hEnSCs, Alg-Cs/Npch/Val, and Alg-Cs/Npch/hEnScs/Val, and the control groups without any intervention. The FTIR spectra showed band frequencies and assignments of Val, Alg-Cs, and alginate. Nanoparticles were formulated with a mean diameter of 187 and 210 nm, for Val/Alg-Cs and Alg-Cs, respectively. The loading of Val into Alg-Cs led to its reduced size by about 40 nm. The Cs-Npch/Val hydrogels degraded faster than the Alg-Cs-/Npch/Val hydrogel specifically in extended time of incubation. A higher swelling capacity of Alg-Cs/Npch hydrogel, compared to Cs/Npch/Val and Alg-Cs/Npch/Val hydrogels, was found. The Cs-Npch/Val hydrogels degraded faster than Alg-Cs-/Npch/Val hydrogel. The Alg-Cs/Npch/hEnSCs/Val could regenerate the damaged nerve fibers and histologically prevent the SCI-induced vacuolization spaces. The prepared Alg-Cs/Npch/Val could be a suitable polymeric carrier for taurine drugs as bioactive substrate in nerve tissue engineering (NTE) and DDS.

Berberine loaded chitosan nanoparticles encapsulated in polysaccharide-based hydrogel for the repair of spinal cord.

The potential of berberine loaded in chitosan nanoparticles (BerNChs) within a hybrid of alginate (Alg) and chitosan (Ch) hydrogel was investigated for the substrate which is known as an inhibit activator proteins. The physicochemical properties of the developed Alg-Ch hydrogel were investigated by fourier-transform infrared spectroscopy. The swelling ability and degradation rate of hydrogels were also analyzed in a phosphate-buffered saline solution at physiological pH. The seeded scaffolds with endometrial stem cells as well as scaffolds alone were then transplanted into hemisected SCI rats. The SEM images displayed the favorable seeding and survival of the cells on the Alg-Ch/BerNChs hydrogel scaffold. The obtained data from immunostining of neuroflilament (NF), as a neuronal growth marker, in the various groups showed that the lowest and highest immunoractivity was belonged to the control and Alg-Ch/BerNCh seeded with ESCs groups, respectively. Finally, the Basso, Beattie, and Bresnahan (BBB) test confirmed the recovery of sensory and motor functions, clinically. The results suggested that combination therapy using the endometrial stem cells seeded on Alg-Ch/BerNChs hydrogel scaffold has the potential to regenerate the injured spinal cord and to limit the secondary damage.

Design, Fabrication, and Testing of a Novel Surgical Handwashing Machine.

Background. Surgical hand scrub is strongly recommended as an essential measure to reduce surgical site infections (SSIs). SSI results in morbidity and additional cost. Micropunctures may occur on surgical gloves during operation, thus hand scrub cannot be omitted in any condition. Generally speaking, the adequacy of hand scrub is decided by the surgeon. Only occasionally, surveillance of hygienic status of hands is performed after scrub. Therefore, the potential exists that suboptimal handwash leads to SSIs. There are standards for preoperative handwash, but all of them are operator dependent, and continuous surveillance is actually impossible. One solution is to omit the role of surgeon in handwashing. This can be achieved by designing a standard procedure, performed mechanically by a machine, considering the detailed requirements of hygienic surgical hand scrub. The goal of this study was to develop a procedure that works on the design, fabrication, and trial of a new handwashing machine, for surgical hand scrub. Methods. A machine with a reciprocal spraying mechanism was designed that covers from the fingertips up to the elbow. Various combinations of staged irrigations with antiseptic solutions and water were to be programmed and implemented. Clinical experiments were performed several times with different handwashing programs, and swabs were taken from the skin surface and creases. Results. There was no microbial growth after 72 hours with any handwashing program. Conclusion. The preliminary experiments with this new handwashing machine show promising results for its application in surgical hand scrub.

A novel haemostatic powder delivery device applicable in minimally invasive surgery.

Haemostatic powder is an effective solution commonly used in various open surgeries. However, there is no specific intra-abdominal delivery device for application of haemostatic powder at the bleeding site during minimally invasive surgery (MIS). In this study, design, construction and test of a novel powder delivery device were carried out. The device uses pressurized gas to deliver the haemostatic powder to the bleeding point. The effect of the gas pressure and the spraying distance on the geometry of the powder dispersion surface area was investigated and found to be significant. The findings indicate that the driving gas pressure range of 60-80 mmHg and the spraying distance range of 2-5 cm achieve the most concentrated powder dispersion surface area. Additionally, in vivo experiments confirmed the effectiveness of the device in live tissue.