3D Printed TCP-Based Scaffold Incorporating VEGF-Loaded PLGA Microspheres for Craniofacial Tissue Engineering

Objective Vascularization is a critical process during bone regeneration/repair and the lack of tissue vascularization is recognized as a major challenge in applying bone tissue engineeringmethods for cranial and maxillofacial surgeries. The aim of our study is to fabricate a vascular endothelial growth factor (VEGF)-loaded gelatin/alginate/β-TCP composite scaffold by 3D printing method using a computer-assisted design (CAD) model. Methods The paste, composed of (VEGF-loaded PLGA)-containing gelatin/alginate/β-TCP in water, was loaded into standard Nordson cartridges and promptly employed for printing the scaffolds. Rheological characterization of various gelatin/alginate/β-TCP formulations led to an optimized paste as a printable bioink at room temperature. Results The in vitro release kinetics of the loaded VEGF revealed that the designed scaffolds fulfill the bioavailability of VEGF required for vascularization in the early stages of tissue regeneration. The results were confirmed by two times increment of proliferation of human umbilical vein endothelial cells (HUVECs) seeded on the scaffolds after 10 days. The compressive modulus of the scaffolds, 98 ± 11 MPa, was found to be in the range of cancellous bone suggesting their potential application for craniofacial tissue engineering. Osteoblast culture on the scaffolds showed that the construct supports cell viability, adhesion and proliferation. It was found that the ALP activity increased over 50% using VEGF-loaded scaffolds after 2 weeks of culture. Significance The 3D printed gelatin/alginate/β-TCP scaffold with slow releasing of VEGF can be considered as a potential candidate for regeneration of craniofacial defects

3D printed tissue engineered model for bone invasion of oral cancer

Recent advances in three-dimensional printing technology have led to a rapid expansion of its applications in tissue engineering. The present study was designed to develop and characterize an in vitro multi-layered human alveolar bone, based on a 3D printed scaffold, combined with tissue engineered oral mucosal model. The objective was to incorporate oral squamous cell carcinoma (OSCC) cell line spheroids to the 3D model at different anatomical levels to represent different stages of oral cancer. Histological evaluation of the 3D tissue model revealed a tri-layered structure consisting of distinct epithelial, connective tissue, and bone layers; replicating normal oral tissue architecture. The mucosal part showed a well-differentiated stratified oral squamous epithelium similar to that of the native tissue counterpart, as demonstrated by immunohistochemistry for cytokeratin 13 and 14. Histological assessment of the cancerous models demonstrated OSCC spheroids at three depths including supra-epithelial level, sub-epithelial level, and deep in the connective tissue-bone interface. The 3D tissue engineered composite model closely simulated the native oral hard and soft tissues and has the potential to be used as a valuable in vitro model for the investigation of bone invasion of oral cancer and for the evaluation of novel diagnostic or therapeutic approaches to manage OSCC in the future

Eco-efficiency measurement and material balance principle:an application in power plants Malmquist Luenberger Index

Incorporating Material Balance Principle (MBP) in industrial and agricultural performance measurement systems with pollutant factors has been on the rise in recent years. Many conventional methods of performance measurement have proven incompatible with the material flow conditions. This study will address the issue of eco-efficiency measurement adjusted for pollution, taking into account materials flow conditions and the MBP requirements, in order to provide ‘real’ measures of performance that can serve as guides when making policies. We develop a new approach by integrating slacks-based measure to enhance the Malmquist Luenberger Index by a material balance condition that reflects the conservation of matter. This model is compared with a similar model, which incorporates MBP using the trade-off approach to measure productivity and eco-efficiency trends of power plants. Results reveal similar findings for both models substantiating robustness and applicability of the proposed model in this paper

Determination of homocysteine using a dopamine-functionalized graphene composite

The electrochemical sensors have an essential role in the detection of amino acids which has clinical uses as a biomarker for a wide range of diseases. In this paper, the dopamine-functionalized graphene oxide was used to develop a screen printed electrochemical sensor (DA-GO/SPE). This sensing platform was used for simultaneous detection of homocysteine and folic acid. An efficient strategy was used for immobilization of dopamine on graphene oxide sheets based on NH2 group of dopamine with the COOH group of GO using the EDC/NHS reaction. The electrochemical investigation of prepared sensing platform confirmed that the DA-GO composite shows excellent catalytic activity toward homocysteine based on EC� mechanism. A pair of redox peaks with one anodic peak (Ep = 220 mV), which related to the oxidation of DA to its quinone structure and one cathodic peak (Ep = 160 mV) was obtained at the DA-GO modified SPE. The values of α and ks for DA at the DA-GO/SPE were calculated to be 0.45 and 2.32 s�1, respectively. The DA-GO/SEP shows good catalytic response toward homocysteine and folic acid with a linear range of 0.5�900 μM and 1.0�260 μM, respectively. The limit of detection of 0.15 μM and 0.32 μM were obtained for homocysteine and folic acid, respectively (S/N = 3). Moreover, the RSD of three measurements using DA-GO/SPE was 1.9, indicating good repeatability. © 2021 Elsevier B.V

Earlier diagnoses of acute leukemia by a sandwich type of electrochemical aptasensor based on copper sulfide-graphene composite

Due to high affinity and specificity of aptamers, they are widely considered for construction of aptasensor to specific recognizing of analytes in biological complex matrix. So, in this work we design a high selective and sensitive aptasensor for leukemia cancer cells (CCRF-CEM) via superior catalytic effect of copper sulfide-graphene (CuS-GR) nanocomposite as label and Au-GR nanocomposite as sensing platform. The CuS-GR nano-composite (label component) is CuS nanoparticles that wrapping on graphene sheets. Its catalytic activity (CuS-GR) increases the current of sensor in parallel with adding of CCRF-CEM and provide sensitive detection of analytes. The detailed of signal amplification and effect on the aptasensor performance completely discussed. This sensor has a linear range of 50�1 � 106 cell mL�1, with a limit of detection of 18 cell mL�1. Also, the developed aptasensor has a significance specificity, high sensitivity and accuracy. It was used for the identification of CCRF-CEM cells in blood samples. © 2020 Elsevier B.V