Biological evaluation of the copper/low-density polyethylene nanocomposite intrauterine device.

Devices and materials intended for clinical applications as medical and implant devices should be evaluated to determine their biocompatibility in physiological systems. This article presents results from cytotoxicity assay of L929 mouse fibroblasts culture, tests for skin irritation, intracutaneous reactivity and sensitization, and material implantation tests for the novel copper/low-density polyethylene nanocomposite intrauterine device (nano-Cu/LDPE IUD) with potential for future clinical utilization. Cytotoxicity test in vitro was conducted to evaluate the change in morphology, growth and proliferation of cultured L929 mouse fibroblasts, which in vivo examination for skin irritation (n = 6) and intracutaneous reactivity (n = 6) were carried out to explore the irritant behavior in New Zealand White rabbits. Skin sensitization was implemented to evaluate the potential skin sensitizing in Hartley guinea pigs (n = 35). The materials were implanted into the spinal muscle of rabbits (n = 9). The cytotoxicity grade of the nano-Cu/LDPE IUD was 0-1, suggested that the composite was nontoxic or mildly cytotoxic; no irritation reaction and skin sensitization were identified in any animals of specific extracts prepared from the material under test; similarly to the control sides, the inflammatory reaction was observed in the rabbits living tissue of the implanted material in intramuscular implantation assay. They indicated that the novel composite intrauterine device presented potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity. The nano-Cu/LDPE IUD has good biocompatibility, which is biologically safe for the clinical research as a novel contraceptive device.

[The subchronic toxicity study on the biological amnion].

As the new type cornea ulcer renovation material, the biological amnion is to be implanted into the human body for a long time, a subchronic toxicity study in rats is made to evaluate its possibility of subchronic toxicity. The study is based on the requirements of "Biological Evaluation of Medical Devices, Part 11: Tests for systemic toxicity and Part 6: Tests for local effects after implantation". After the implantation of examples to be tested, animals were observed daily for mortality and 92 days later the possible subchronic toxicity was evaluated. And a necropsy was conducted and the selected organs were excised, weighed, and processed histologically. Body weights, organ weights, organ/body weight ratios, hematology values and clinical chemistry values were analyzed statistically. Results show that daily clinical observation, body weights, necropsy findings, organ weights and organ/body weight ratios were within acceptable limits in test and control treatment groups. There were no obvious changes in histopathology, hematology values or clinical chemistry values in either male or female rats and no notable differences between the biological amnion and the control amnion. This study proves that, the cornea ulcer renovation material, the biological amnion does not induce subchronic toxicity.