Preparation and Osteogenic Efficacy of Emodin-loaded Hydroxyapatite Electrospun Fibers

Biological scaffolds have been the focus of bone tissue engineering research in recent years. In this paper, emodin (EM), macromolecular compound polycaprolactone (PCL), and hydroxyapatite (HA) were used as raw materials to prepare EM/PCL/HA fibers containing different EM ratios by electrospinning, and the properties and osteogenic efficacy of EM/PCL/HA were studied. Scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were used to characterize the structures of HA and the electrospun fibers. Results showed that HA has high crystallinity and loose porous structure, and the electrospun fibers have a smooth and flat surface. In vitro release results showed that EM was slowly released from EM/PCL/HA within 216 h. Cell proliferation assay in mouse embryonic osteoblast precursor cells (MC3T3-E1) exhibited that 5% EM/PCL/HA had the best effect on promoting cell proliferation. Alkaline phosphatase (ALP) and mineralized nodules staining results also showed that 5% EM/PCL/HA had the best effect on promoting osteogenic differentiation. qRT-PCR results showed that the mRNA expression level of osteoblast differentiation markers, namely, bone morphogenetic protein (BMP)-2, BMP-9, and osteocalcin were significantly upregulated by 5% EM/PCL/HA treatment. These results indicate that EM/PCL/HA is a potential osteogenic material, which can provide a reference for the development of bone injury repair materials.

Comparison of different treatment planning approaches using VMAT for head and neck cancer patients with metallic dental fillings

Objective:To explore treatment planning approaches using volumetric modulated arc therapy(VMAT)for head and neck cancer patients with metallic dental fillings.Methods:Fifty-six patients with metallic dental fillings treated with radiotherapy were selected,and three VMAT plans,the jaw-tracking plan,fixed-jaw plan,and non-coplanar plan,were designed for each patient.In the jawtracking plan,two coplanar partial arc fields that avoid the metal area were set,and the jaw was automatically tracked.In the fixed-jaw plan,different fields were set in three sections according to the fixed-jaw method.The fields were the same as those in the jaw-tracking plan for the section containing metal implants,while full arc fields were set in the nonmetal sections.In the non-coplanar plan,a non-coplanar arc field was added based on the jaw-tracking plan.The treatment plan in the jaw-tracking plan was optimized,and the constraints on the planning target volume(PTV)or organs at risk(OARs)in the jaw-tracking plan were copied to the other two plans.The dose distribution in PTV and OARs of the patients in the three treatment plans was compared.Results:There were no significant differences in the maximum doses to the spinal cord or optic nerves among the three treatment plans.However,compared with the jaw-tracking plan,the fixed-jaw plan showed lower mean doses to the pharynx[(42.9±7.1)Gy vs.(44.1±7.1)Gy,P<0.05]and larynx[(43.9±3.9)Gy vs.(45.4±4.7)Gy,P<0.05],while the non-coplanar plan obtained significantly better dose distribution in PTV and all OARs except for the spinal cord and optic nerves.Meanwhile,the non-coplanar plan performed significantly better than the fixed-jaw plan in terms of the maximum doses to the brainstem[(50.24.0)Gy vs.(51.4±4.6)Gy,P<0.05],left lens[(5.8±0.2)Gy vs.(6.3±0.4 Gy),P<0.05],and right lens[(5.9±0.3)Gy vs.(6.2±0.3)Gy,P<0.05].Conclusions:The non-coplanar VMAT is an optimal method for treating head and neck cancer patients with metallic dental fillings since it can provide better dose distribution in PTV and reduce doses to OARs.

A flexible conductive hybrid elastomer for high-precision stress/strain and humidity detection

Flexible and environment-responsive materials are essential for a large number of applications from artificial skin to wearable devices. The present study develops a flexible, ultra-low cost conductive hybrid elastomer(CHE), which possesses high responsive capabilities to stress/strain and humidity. CHE was composed of polydimethylsiloxane(PDMS) and starch hydrogel(SH), enabling great elasticity(56 kPa),high conductivity(10^(-2)S/m) and high sensitivity to external stimuli(gauge factor of CHE under stress and strain are 0.71 and 2.22, respectively, and sensitivity to humidity is 1.2 × 10^(-6)S/m per RH%). These properties render CHE a promising candidate for artificial skin and wearable electronics applications of continuously monitoring environmental information.