Assessment of structural, biological and drug release properties of electro-sprayed poly lactic acid-dexamethasone coating for biomedical applications

Mostafa Rahvar,Gholamreza Ahmadi Lakalayeh,Niloofar Nazeri,Bahereh T. Marouf,Mahdieh Shirzad,Azar Najafi T. Shabankareh,Hossein Ghanbari 대한의용생체공학회 2021 Biomedical Engineering Letters (BMEL) Vol.11 No.4

The efficacy of an implant is highly depends on its coating characteristics mainly determined by polymer properties and coating technique. Electro-spraying is an inexpensive and versatile coating technique with various advantages for biomedical application. In this study, the efficacy of electro-sprayed (ES) poly lactic acid (PLA)-dexamethasone (DEX) coatings for medical implants was evaluated and compared with spin-coated samples as control. Structural properties of coatings were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Confocal and scanning electron microscopy (SEM), contact angle measurement and nanoindentation tests were used to study surface properties. Coating degradation rate and drug release profile were studied for 40 days. Cell viability experiments were also performed on human endothelial (HUVEC) and smooth muscle cells (HUASMC) using MTT assay and SEM. XRD and DSC analysis showed electro-spraying significantly reduce PLA and DEX crystallinity. Surface studies showed ES coatings has significantly higher hydrophobicity and roughness with microbead-nanofiber morphology vs. micro-nanoporous structure of spin-coated samples. Initial burst release of DEX was 22% and 10% after 6 h and total release was 71% and 46% after 40 days for ES and spin-coated samples, respectively. HUVEC viability of ES samples was higher than spin-coated ones after 1 and 4 days. However, dexamethasone release profile reduced HUASMC proliferation in ES PLA-DEX samples in comparison to spin-coated after 1 and 3 days. In conclusion, in vitro results showed potential of ES PLA-DEX as a biocompatible and efficient anti-inflammatory coating with suitable drug release profile for future applications such as coronary drug eluting stents.

Improved Efficacy of a Dendritic Cell-Based Vaccine against a Murine Model of Colon Cancer: The Helper Protein Effect

Amir-Hassan Zarnani,Monireh Torabi-Rahvar,Mahmood Bozorgmehr,Mehri Zareie,Nazanin Mojtabavi 대한암학회 2015 Cancer Research and Treatment Vol.47 No.3

Purpose Targeted immunotherapy using dendritic cells (DCs) has been employed in numerous investigations aiming at combating neoplasms. We previously showed that copulsing of an antigen with a helper protein could considerably enhance antigen presenting capacity of ex vivo–generated DCs. In this study, we attempted to administer an effective treatment in a murine model of colon cancer with DCs pulsed with the mixture of a tumor-specific gp70-derived peptide (AH1) and a helper protein, ovalbumin (OVA). Materials and Methods First, the presence of gp70 in CT26 tumor cells and tumor tissues was verified using immunofluorescence and Western blot analyses. Next, DCs were purified from normal mice, loaded ex vivowith AH1 and OVA (DC-Pep-OVA), and injected into tumor-bearing mice. Tumor volume, in vitro antigen (Ag)-specific proliferation of splenic cells, and survival rate were measured to determine the efficacy of DC-Pep-OVA. As the control groups, tumor-bearing mice were vaccinated with DC-Pep, unpulsed DC, and DCs loaded with a mixture of OVA and an irrelevant peptide (P15), or were not vaccinated at all. Results DC-Pep-OVA showed superior efficacy over other groups, as indicated by smaller tumor volume, higher Ag-specific proliferation rate of splenic cells, and prolonged survival. Conclusion Overall, in the present study we showed for the first time that DCs copulsed with AH1 (tumor Ag) and OVA (helper molecule) could be considered as potentially robust weapons for use in future antitumor immunotherapies.

Polyurethane/Gelatin Nanofiber Neural Guidance Conduit in Combination with Resveratrol and Schwann Cells for Sciatic Nerve Regeneration in the Rat Model

Majid Salehi,Arian Ehtrami,Farshid Bastami,Saeed Farzamfar,Sepanta Hosseinpour,Hamid Vahedi,Ahmad Vaez,Mostafa Rahvar,Arash Goodarzi 한국섬유공학회 2019 Fibers and polymers Vol.20 No.3

Peripheral nerve injury is a serious challenge which influences 2.8 percent of trauma patients. Tissue engineeringof peripheral nerves mainly focuses on axonal regeneration via various nerve guides. The aim of this study is to evaluate a novel polyurethane (PU)/gelatin nanofibers (GNFs) conduit’s potential combination with resveratrol (RVT) for sciatic nerve regeneration in the rat. Platelet-rich plasma (PRP) was used as a carrier for RVT. Different tests like contact angle, tensile strength etc. was used to evaluate properties of PU/GNFs conduits. In addition, the electron microscopy, MTT assay, and DAPI staining revealed its compatibility with Schwann cells. 24 male Wistar rats were allocated into four groups (n=6) (1) PU/GNF/PRP/Schwann cell, 2) PU/GNF/Schwann cell/PRP/RVT, 3) Positive control, and 4) Negative control in order to assess sciatic functional index (SFI), hot plate latency, electromyographical (EMG), the percentage of wet weight-loss of gastrocnemius muscle and histopathological studies using hematoxylin-eosin staining. The results represented sciatic functional index (SFI), hot plate latency, electromyographical improved significantly in group 1 and 2 compared to the negative control group. Histopathological findings showed remarkable improvements in myelin sheath regeneration and fibers condition in group 1 and 2 compared to the negative control group. Group 2 showed more resemblance to the normal sciatic nerve, with well-arranged fibers and an intact myelin sheath. This study successfully applied PU/GNFs/PRP/RVT conduits as a potential biocompatible nerve guide with proper mechanical properties, biocompatibility, and biodegradability that enhanced injured sciatic nerve’s recovery rate.

Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring

Mancini, L.,Giacobbe, P.,Littlefair, S. P.,Southworth, J.,Bozza, V.,Damasso, M.,Dominik, M.,Hundertmark, M.,Jørgensen, U. G.,Juncher, D.,Popovas, A.,Rabus, M.,Rahvar, S.,Schmidt, R. W.,Skottfelt, J.,S EDP Sciences 2015 Astronomy and astrophysics Vol.584 No.-

<P>Context. Photometric monitoring of the variability of brown dwarfs can provide useful information about the structure of clouds in their cold atmospheres.The brown-dwarf binary system Luhman16AB is an interesting target for such a study, because its components stand at the L/T transition and show high levels of variability. Luhman16AB is also the third closest system to the solar system, which allows precise astrometric investigations with ground-based facilities. Aims. The aim of the work is to estimate the rotation period and study the astrometric motion of both components. Methods. We have monitored Luhman16AB over a period of two years with the lucky-imaging camera mounted on the Danish 1.54m telescope at La Silla, through a special i + z long-pass filter, which allowed us to clearly resolve the two brown dwarfs into single objects. An intense monitoring of the target was also performed over 16 nights, in which we observed a peak-to-peak variability of 0.20±0.02mag and 0.34±0.02mag for Luhman16A and 16B, respectively. Results. We used the 16-night time-series data to estimate the rotation period of the two components. We found that Luhman16B rotates with a period of 5.1 ±0.1h, in very good agreement with previous measurements. For Luhman16A, we report that it rotates more slowly than its companion, and even though we were not able to get a robust determination, our data indicate a rotation period of roughly 8h. This implies that the rotation axes of the two components are well aligned and suggests a scenario in which the two objects underwent the same accretion process. The 2-year complete data set was used to study the astrometric motion of Luhman16AB. We predict a motion of the system that is not consistent with a previous estimate based on two months of monitoring, but cannot confirm or refute the presence of additional planetary-mass bodies in the system.</P>

High-precision photometry by telescope defocusing - VII. The ultrashort period planet WASP-103

Southworth, J.,Mancini, L.,Ciceri, S.,Budaj, J.,Dominik, M.,Figuera Jaimes, R.,Haugbolle, T.,Jorgensen, U. G.,Popovas, A.,Rabus, M.,Rahvar, S.,von Essen, C.,Schmidt, R. W.,Wertz, O.,Alsubai, K. A.,Boz Oxford University Press 2015 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.447 No.1