ABSTRACT
BACKGROUND: Low temperature vaporized hydrogen peroxide sterilization (VH2O2) is used in hospitals today to sterilize reusable medical devices. VH2O2 sterilized 3D printed materials were evaluated for sterilization, biocompatibility and material compatibility. MATERIALS & METHODS: Test articles were printed at Formlabs with BioMed Clear™ and BioMed Amber™, and at Stratasys with MED610™, MED615™ and MED620™. Sterilization, biocompatibility and material compatibility studies with 3D printed materials were conducted after VH2O2 sterilization in V-PRO™ Sterilizers. The overkill method was used to evaluate sterilization in a ½ cycle. Biocompatibility testing evaluated the processed materials as limited contact (< 24-hours) surface or externally communicating devices. Material compatibility after VH2O2 sterilization (material strength and dimensionality) was evaluated via ASTM methods and dimensional analysis. RESULTS: 3D printed devices, within a specific design window, were sterile after VH2O2 ½ cycles. After multiple cycle exposure, the materials were not cytotoxic, not sensitizing, not an irritant, not a systemic toxin, not pyrogenic and were hemo-compatible. Material compatibility via ASTM testing and dimensionality evaluations did not indicate any significant changes to the 3D printed materials after VH2O2 sterilization. CONCLUSION: Low temperature vaporized hydrogen peroxide sterilization is demonstrated as a suitable method to sterilize 3D printed devices. The results are a subset of the data used in a regulatory submission with the US FDA to support claims for sterilization of 3D printed devices with specified materials, printers, and device design 1.
ABSTRACT
In this study, we used ELISPOT to quantify frequencies of bronchoalveolar lavage (BAL) and peripheral blood T cells capable of producing IFNγ in response to PPD, antigen 85B, and Mtb-specific antigens CFP-10 and ESAT-6 in individuals with latent tuberculosis infection (LTBI) and Mtb-naïve controls. Compared to peripheral blood, BAL cells of LTBI subjects displayed significant enrichment for T cells responding to PPD, antigen 85B, and CFP-10, but not to ESAT-6. Baseline BAL cells of LTBI subjects displayed significant production of Mig (CXCL9) in response to PPD, antigen 85B, and CFP-10 as well. These findings suggest that enrichment for Mtb-specific T cells within BAL is not unique to active pulmonary tuberculosis and may, to the contrary, contribute to protection from re-infection in Mtb immune individuals.