The 90:10 PLGA(Cat# AP49; Polyscitech, Western Lafayette, IN, USA) was dissolved in chloroform at 10 wt/vol% and sonicated for 1 h at 40 C. ions nor press intentionally modified up to alkaline pH 9 induced any detectable adverse effects on HUVEC reactions. In contrast, the significantly higher, yet non-cytotoxic, Zn2+ ion concentration from your degradation of ZSr41D alloy was likely the cause for the in the beginning higher VCAM-1 manifestation on cultured HUVECs. Lastly, analysis of the HUVEC-ZSr41 interface showed near-complete absence of cell adhesion directly on the sample surface, Arteether most likely caused by either a high local alkalinity, change in surface topography, and/or surface composition. The culture method used in this study was proposed as a valuable tool for studying the design aspects of Zn-containing Mg-based biomaterials studies showed that CAM expression in ECs was activated by Arteether elevated concentrations of metallic Arteether ions typically found in permanent metallic implants [7,15C23]. Vascular cell adhesion molecule-1 (VCAM-1) is an immunoglobulin superfamily-specific receptor that provides high-affinity interactions between ECs and integrins around the leukocyte surface and facilitates transendothelial migration [10,13,14]. Moreover, VCAM-1 binds with monocytes, but not neutrophils, and it is the first CAM expressed in chronic inflammation such as atherosclerosis (before atherosclerotic plaque development) [13,14,24] and restenosis following coronary stent implantation . Thus, VCAM-1 can be used as an indicator of EC activation during the early stages of inflammation. Furthermore, previous studies supported the applicability of human umbilical vein endothelial cells (HUVEC) to model and investigate components of the inflammatory response, such as CAM expression [7,17]. Previously, we reported the development of Mg-Zinc-Strontium (Mg-Zn-Sr) ternary alloys and the evaluation of their biological performance for biomedical applications [26C28]. Furthermore, we reported the direct culture method to mimic physiological conditions and evaluate cell responses at the cell-biomaterial interface (method, as compared with ISO 10993-based methods, for the initial rapid screening of cytocompatibility and degradation of Mg-based biomaterials . The direct culture method was introduced as part of a field-wide effort to improve and standardize the testing of Mg-based biomaterials [29C32]. Thus, the first objective Tsc2 of this study was to investigate the degradation and cytocompatibility of four Mg-4Zn-xSr alloys (x = 0.15, 0.5, 1.0, 1.5 wt%; designated as ZSr41A, B, C, and D respectively) in the direct culture with HUVECs studies reported adequate immunological response during the foreign body reaction or fibrosis stages following implantation of Mg-based materials [33C37], sparse literature is found around the early-stage inflammatory response. Specifically, to the authors knowledge, early-stage inflammatory induction by the degradation of Mg-based materials has only been investigated with primary murine and human macrophages  and with dendritic cells . In both cases, the Mg-based materials and the respective degradation products were not found to have detrimental immunomodulatory effects. This study reported for the first time around the transient inflammatory activation of ECs induced by the degradation products of Zn-containing Mg alloys. 2. Materials and methods 2.1. Preparation of ZSr41 alloys, Mg control, and reference materials The ZSr41 alloys in this study had a nominal composition of 4 wt% Zn with 0.15, 0.5, 1.0, or 1.5 wt% Sr; these alloys were designated as ZSr41A, ZSr41B, ZSr41C, and ZSr41D accordingly with increasing Sr content. Details pertaining to the metallurgical process and heat treatment used for alloy preparation are described elsewhere [26,27]. The heat-treated 1.0 mm thick sheets of ZSr41 alloys were cut into 5 5 mm squares. Likewise, commercially real Mg linens (99.9%, As-rolled, 1.0 mm thick, Cat# 40604; Alfa Arteether Aesar, Ward Hill, MA, USA) were cut into 5 5 mm squares and used as a control in this study. Commercially available AZ31 (1.0 mm thick, Cat# 44009; Alfa Aesar) and Nitinol (NiTi; 0.25 mm thick, Cat# 44953; Alfa Aesar) linens were cut into 5 5 mm squares and used as metallic reference materials in this study. AZ31 was included in this study since it has been used previously as a reference material for the investigation of Mg-based materials [40C42]; likewise, NiTi was included due to the widespread use for cardiovascular stents . Additionally, 90:10 polylactic-co-glycolic Arteether acid (PLGA) was included in this study as a non-metallic reference material due to the use of PLGA-based coatings to control the degradation of Mg-based materials for cardiovascular stents [43,44]. The PLGA samples were prepared by spin coating onto the non-tissue culture treated glass (Cat# 12-544-1; Fisher Scientific, Hampton, NH, USA), which was cut into 5 .