The study of the sterilization effect of gamma ray irradiation of immobilized collagen polypropylene nonwoven fabric surfaces

Abstract

Exposure to gamma ray irradiation is a frequent, clean, and superior method used to prevent bacterial contamination of sterilized biomedical end products. However, the potential damage induced by gamma ray irradiation of collagen is of concern because of the decay of bioactivity, which correlates with considerable structural alterations. In this experiment, antenna-coupling microwave plasma was utilized to activate nonwoven polypropylene (PP) fabric, and then the sample was grafted to acrylic acid (AAc). Type III collagen was immobilized by using water-soluble 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a coupling agent. The collagen-immobilized samples, with temperatures of under 4 degrees C, were exposed to gamma ray irradiation at different dose intervals. Gamma ray irradiation was applied to evaluate the bioactivity on the collagen-immobilized nonwoven polypropylene and to determine the results of sterilization. Five kinds of sterilization index bacteria, all subject to Good Manufacturing Practice (GMP) criteria, were applied as a standard plate-count sterilization test. Our experimental results demonstrate that in human plasma incubated with various intervals of gamma ray irradiation, fibrinogen concentration decreases while platelet and red blood cell adhesion increase. However, the dose required for thrombination demonstrated a significant change in gamma ray irradiation exposure of fewer than 10 KGy (p = 0.05). The decay of bioactivity of the gamma-ray-irradiated collagen-bonded surfaces was evaluated and indicated that the decrease of R-CONHR', the degradation of amides ([broken bond]C[bond]N bonds of collagen and formation of the ROCNH(2) and O[double bond]CR' bonds), and the increase of C[bond]O, C[double bond]O bonds gradually may damage collagen by increasing the intervals of gamma ray irradiation. These effects considerably influence the bioactivity of the collagen-bonded fabric. It is clear that gamma ray irradiation exposure of approximately 10 KGy has the potential of moderating the bioactivities of collagen and therefore likely is a vital factor in the acceleration of biodegradation. The dose required for thrombination and sterilization reaches significance at 7.5 KGy.

Analysis of sterilization protocols for peptide‐modified hydrogels

“…Radiation within the gamma frequency range (> 3*10 19 Hz) penetrates packaging materials, and can be easily applied on a large scale at ambient temperatures, making it ideal for terminal sterilization. Thus, γ‐irradiation has been studied extensively in both the food1, 5, 6, 13–15 and medical1, 3, 9, 16–27 industries. Irradiation leaves no toxic byproducts,3, 4 making it an attractive alternative to ethylene oxide, a carcinogen which may be retained by implant materials if processing measures to remove it are inadqequate 4, 10…”

“…Degradation of 0.5 kGy irradiated myoglobin15 and ovalbumin27 has been shown using SDS‐page analysis. Tyan and colleagues noted that adhesion of platelets and red blood cells to surface‐immobilized collagen was altered as a result of 5 kGy γ‐irradiation 21. γ‐Irradiation also significantly alters the mechanical properties of synthetic biomaterials like PLGA8 and PLLA,22 natural biomaterials like gelatin23 and collagen25 and physiological tissues like bone 24…”

An Improved Method for the Preparation of Type I Collagen From Skin

“…Many commercial sources of COL1 have been effectively sterilized by gamma-irradiation. Unfortunately, this practice greatly reduces its ability to form gels due to protein fragmentation and denaturation 9,10 . This procedure represents the optimal conditions for COL1 extraction as determined from many experiments performed to establish the ideal proportion of dermal sample to buffer volume.…”

Contamination from Sterilization Procedures

“…Tyan et al [30] investigated the effect of gamma-ray irradiation (from 5 to 40 kGy) on immobilized collagen and concluded that scission of the peptide linkage occurred. They attributed the increase in amide nitrogen and the detection of carbonyl groups in irradiated collagen to the breaking of -C-nbonds according to the reaction (12.7)…”