Biocompatibility Assessment of Poly(lactic acid) Films after Sterilization with Ethylene Oxide in Histological Study In Vivo with Wistar Rats and Cellular Adhesion of Fibroblasts In Vitro

Abstract

Biomaterials must meet certain fundamental requirements for their usage in living beings, such as biocompatibility, bifunctionality, and sterilizability, without having chemical and structural changes. The biocompatibility of poly(lactic acid) (PLA) films, shaped by compression, was evaluated after sterilization by ethylene oxide by a histological in vivo test with Wistar rats and cytotoxicity in cell adhesion in vitro. The cytotoxicity test was performed by the reduction of tetrazolium salt (MTT). Thermal and chemical changes in PLA films concerning the proposed sterilization process and characteristics were not observed to evidence polymer degradation due to sterilization. The analysis of the cytotoxicity by the MTT method has shown that the sterilized PLA films are not cytotoxic. The adhesion and proliferation of fibroblasts on PLA films were homogeneously distributed over the evaluation period, showing an elongated appearance with unnumbered cytoplasmic extensions and cell-cell interactions. By examining the biocompatibility in a histological study, a mild tissue inflammation was observed with the presence of fibrosis in the samples that had been exposed for 21 days in the rats' bodies. PLA films sterilized with ethylene oxide did not exhibit cell adhesion in vitro and toxicity to the surrounding tissue in vivo and they may be used in future in vivo testing, according to histological findings in Wistar rats in the present study.

Elaboration and Biocompatibility of an Eggshell-Derived Hydroxyapatite Material Modified with Si/PLGA for Bone Regeneration in Dentistry

“…This polymer has been shown to modify the biodegradability and interconnectivity properties of the HAp material and improve its cellular colonization. Likewise, this material neither seems to affect the ionic concentrations of Ca and P, nor the surrounding pH [59, 69]. The freezing-lyophilization method used to add PLGA in the present study was the same technique proposed by Raman [60], which was fast and efficient.…”

“…The obtained mixture was transferred to plastic moulds (Cryovial) and frozen for 24 h at −80°C. After this process, the material was compacted every 4 h for 2 days and subsequently lyophilized at −53°C for 24 h [59]. The samples were cut into disks with approximate dimensions of 6 mm (diameter) × 1.5 mm (thickness) and then sterilized with ethylene oxide [60].…”

In-situ Real-time Field Imaging and Monitoring of Leaf Stomata by High-resolution Portable Microscope

“…The upper leaf holder is attached to an x-y-z stage to focus the leaf surface for microscopic imaging. A lower leaf holder of thickness 1.5 mm is fabricated with a black color biocompatible polylactic acid (PLA) material to restrict the ambient light reaching to the sample from backside [25,26]. The thickness of the lower leaf holder was determined after considering the distance between the leaf surface and an objective lens (~2.5 mm) when the lower epidermis was in focus.…”

“…6 [29]. A black color lower leaf holder restricts the ambient light reaching to the sample from backside [25,26]. Further, to avoid the interference of ambient light reflected from lens surface with the optical system of the microscope, the lens was covered with a black color cap made of PLA material.…”

“…[23][24][25][26].Our leaf holder allows the upper surface of a leaf open to the sunlight and the lower surface of the leaf to the wind simultaneously. Thick transparent acryl sheet of upper leaf holder holds the leaf in a position and allows the sunlight on the upper epidermis of a leaf, a predominant stimulus affecting the stomatal aperture…”