A Novel Electrochemical Biosensor Based On Fe3O4 Nanoparticles-Polyvinyl Alcohol Composite for Sensitive Detection of Glucose

In this research, a new electrochemical biosensor was constructed for the glucose detection. Iron oxide nanoparticles (Fe3O4) were synthesized through co-precipitation method. Polyvinyl alcohol-Fe3O4 nanocomposite was prepared by dispersing synthesized nanoparticles in the polyvinyl alcohol (PVA) solution. Glucose oxidase (GOx) was immobilized on the PVA-Fe3O4 nanocomposite via physical adsorption. The mixture of PVA, Fe3O4 nanoparticles and GOx was drop cast on a tin (Sn) electrode surface (GOx/PVA-Fe3O4/Sn). The Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD). Also, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) techniques were utilized to evaluate the PVA-Fe3O4 and GOx/PVA-Fe3O4 nanocomposites. The electrochemical performance of the modified biosensor was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Presence of Fe3O4nanoparticles in the PVA matrix enhanced the electron transfer between enzyme and electrode surface and the immobilized GOx showed excellent catalytic characteristic toward glucose. The GOx/PVA-Fe3O4/Sn bioelectrode could measure glucose in the range from 5 × 10−3 to 30 mM with a sensitivity of 9.36 μA mM−1 and exhibited a lower detection limit of 8 μM at a signal-to-noise ratio of 3. The value of Michaelis-Menten constant (KM) was calculated as 1.42 mM. The modified biosensor also has good anti-interfering ability during the glucose detection, fast response (10 s), good reproducibility and satisfactory stability. Finally, the results demonstrated that the GOx/PVA-Fe3O4/Sn bioelectrode is promising in biosensor construction

Development of Optical Biosensor Technologies for Cardiac Troponin Recognition

Acute myocardial infarction (AMI) is the leading cause of death among cardiovascular diseases. Among the numerous attempts to develop coronary marker concepts into clinical strategies, cardiac troponin is known as a specific marker for coronary events. The cardiac troponin concentration level in blood has been shown to rise rapidly for 4–10 days after onset of AMI, making it an attractive approach for a long diagnosis window for detection. The extremely low clinical sensing range of cardiac troponin levels consequently makes the methods of detection highly sensitive. In this review, by taking into consideration optical methods applied for cardiac troponin detection, we discuss the most commonly used methods of optical immunosensing and provide an overview of the various diagnostic cardiac troponin immunosensors that have been employed for determination of cardiac troponin over the last several years

Development of 3D PCL microsphere/TiO\u3csub\u3e2\u3c/sub\u3e nanotube composite scaffolds for bone tissue engineering

In this research, the three dimensional porous scaffolds made of a polycaprolactone (PCL) microsphere/TiO2 nanotube (TNT) composite was fabricated and evaluated for potential bone substitute applications. We used a microsphere sintering method to produce three dimensional PCL microsphere/TNT composite scaffolds. The mechanical properties of composite scaffolds were regulated by varying parameters, such as sintering time, microsphere diameter range size and PCL/TNT ratio. The obtained results ascertained that the PCL/TNT (0.5 wt%) scaffold sintered at 60 °C for 90 min had the most optimal mechanical properties and an appropriate pore structure for bone tissue engineering applications. The average pore size and total porosity percentage increased after increasing the microsphere diameter range for PCL and PCL/TNT (0.5 wt%) scaffolds. The degradation rate was relatively high in PCL/TNT (0.5 wt%) composites compared to pure PCL when the samples were placed in the simulated body fluid (SBF) for 6 weeks. Also, the compressive strength and modulus of PCL and PCL/TNT (0.5 wt%) composite scaffolds decreased during the 6 weeks of storage in SBF. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay and alkaline phosphates (ALP) activity results demonstrated that a generally increasing trend in cell viability was observed for PCL/TNT (0.5 wt%) scaffold sintered at 60 °C for 90 min compared to the control group. Eventually, the quantitative RT-PCR data provided the evidence that the PCL scaffold containing TiO2 nanotube constitutes a good substrate for cell differentiation leading to ECM mineralization

Evaluation of Glycated Albumin (GA) and GA/Hba1c Ratio for Diagnosis of Diabetes and Glycemic Control: A Comprehensive Review

Diabetes Mellitus (DM) is a group of metabolic diseases characterized by chronic high blood glucose concentrations (hyperglycemia). When it is left untreated or improperly managed, it can lead to acute complications including diabetic ketoacidosis and non-ketotic hyperosmolar coma. In addition, possible long-term complications include impotence, nerve damage, stroke, chronic kidney failure, cardiovascular disease, foot ulcers, and retinopathy. Historically, universal methods to measure glycemic control for the diagnosis of diabetes included fasting plasma glucose level (FPG), 2-h plasma glucose (2HP), and random plasma glucose. However, these measurements did not provide information about glycemic control over a long period of time. To address this problem, there has been a switch in the past decade to diagnosing diabetes and its severity through measurement of blood glycated proteins such as Hemoglobin A1c (HbA1c) and glycated albumin (GA). Diagnosis and evaluation of diabetes using glycated proteins has many advantages including high accuracy of glycemic control over a period of time. Currently, common laboratory methods used to measure glycated proteins are high-performance liquid chromatography (HPLC), immunoassay, and electrophoresis. HbA1c is one of the most important diagnostic factors for diabetes. However, some reports indicate that HbA1c is not a suitable marker to determine glycemic control in all diabetic patients. GA, which is not influenced by changes in the lifespan of erythrocytes, is thought to be a good alternative indicator of glycemic control in diabetic patients. Here, we review the literature that has investigated the suitability of HbA1c, GA and GA:HbA1c as indicators of long-term glycemic control and demonstrate the importance of selecting the appropriate glycated protein based on the patient’s health status in order to provide useful and modern point-of-care monitoring and treatment

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

A Graphene Based–biomimetic Molecularly Imprinted Polyaniline Sensor for Ultrasensitive Detection of Human Cardiac Troponin T(cTnT)

In the present work, a biomimetic nano-molecularly imprinted polymer (N-MIP) electrode based on a graphene screen-printed electrode was developed for the ultrasensitive detection of cardiac troponin T (cTnT). The biomimetic cavities for targeted sensing for analyte were fabricated by the electropolymerization of conductive co-polymer matrix of aniline and carboxylated aniline on the graphene oxide (GO) electrode, in the presence template protein (cTnT for cardiac troponin T probe) by cyclic voltammetry. The surface characterization of the sensor was performed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and scanning electron microscopy (SEM). The best biomimetic surface nanotexture was obtained at aniline/carboxylatedaniline ratio of 1:4. The linear range of cTnT probe was in the range of 0.02 to 0.09 ng/mL, with the detection limit of 0.008 ng/mL. The reliability of the N-MIP cTnT sensor was examined by comparing the results with those obtained from HPLC method, and it was observed that the results from N-MIP sensors and HPLC have a great correlation

Development of Chitosan/Gelatin/Keratin Composite Containing Hydrocortisone Sodium Succinate as a Buccal Mucoadhesive Patch to Treat Desquamative Gingivitis

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH = 7.4) containing 104 U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications

Mechanical Properties of 3D Printed Reinforced Polycaprolactone Composite Scaffolds

Objectives This paper describes the fabrication of a new porous 3D-printed scaffold composed of polycaprolactone (PCL) and polyether-ether ketone (PEEK) micro-particles for bone tissue engineering (BTE) applications. Methods In order to improve the compatibility of the reinforcing PEEK powder with polycaprolactone, the PEEK powder was surface-modified by an amino-silane coupling agent. After modification, Fourier-transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC) were used to investigate the chemical reaction between PEEK and silane coupling agent. In order to increase the compressive modulus of the 3D printed PCL scaffold, 10% silane-modified PEEK was incorporated into the PCL polymeric matrix. Scanning electron microscopy (SEM) was used for cell morphology and attachment evaluation. Results The results indicated that the silane coupling agent was successfully grafted onto the particle surface. The compressive modulus of PCL scaffold increased by incorporating the silane-modified PEEK, despite having higher porosity, compared with the pure PCL scaffolds. Addition of amino-silane had a positive impact on cell response, and that surface modification led to improved particle dispersion. Conclusion In conclusion, it seems that the incorporation of surface-modified PEEK micro-particles into the PCL porous scaffold could enhance its mechanical properties, and may be applicable for the management of large bone defects

A Current Overview of Materials and Strategies for Potential Use in Maxillofacial Tissue Regeneration

Tissue regeneration is rapidly evolving to treat anomalies in the entire human body. The production of biodegradable, customizable scaffolds to achieve this clinical aim is dependent on the interdisciplinary collaboration among clinicians, bioengineers and materials scientists. While bone grafts and varying reconstructive procedures have been traditionally used for maxillofacial defects, the goal of this review is to provide insight on all materials involved in the progressing utilization of the tissue engineering approach to yield successful treatment outcomes for both hard and soft tissues. In vitro and in vivo studies that have demonstrated the restoration of bone and cartilage tissue with different scaffold material types, stem cells and growth factors show promise in regenerative treatment interventions for maxillofacial defects. The repair of the temporomandibular joint (TMJ) disc and mandibular bone were discussed extensively in the report, supported by evidence of regeneration of the same tissue types in different medical capacities. Furthermore, in addition to the thorough explanation of polymeric, ceramic, and composite scaffolds, this review includes the application of biodegradable metallic scaffolds for regeneration of hard tissue. The purpose of compiling all the relevant information in this review is to lay the foundation for future investigation in materials used in scaffold synthesis in the realm of oral and maxillofacial surgery

Inhibition of \u3cem\u3eCandida albicans\u3c/em\u3e and Mixed Salivary Bacterial Biofilms on Antimicrobial Loaded Phosphated Poly(methyl methacrylate)

Biofilms play a crucial role in the development of Candida-associated denture stomatitis. Inhibition of microbial adhesion to poly(methyl methacrylate) (PMMA) and phosphate containing PMMA has been examined in this work. C. albicans and mixed salivary microbial biofilms were compared on naked and salivary pre-conditioned PMMA surfaces in the presence or absence of antimicrobials (Cetylpyridinium chloride [CPC], KSL-W, Histatin 5 [His 5]). Polymers with varying amounts of phosphate (0–25%) were tested using four C. albicans oral isolates as well as mixed salivary bacteria and 24 h biofilms were assessed for metabolic activity and confirmed using Live/Dead staining and confocal microscopy. Biofilm metabolism was reduced as phosphate density increased (15%: p = 0.004; 25%: p = 0.001). Loading of CPC on 15% phosphated disks showed a substantial decrease (p = 0.001) in biofilm metabolism in the presence or absence of a salivary pellicle. Salivary pellicle on uncharged PMMA enhanced the antimicrobial activity of CPC only. CPC also demonstrated remarkable antimicrobial activity on mixed salivary bacterial biofilms under different conditions displaying the potent efficacy of CPC (350 µg/mL) when combined with an artificial protein pellicle (Biotene half strength)