Daysi M. Diaz-Diestra, Ph.D., DABT
Senior Toxicologist
Dr. Diaz-Diestra is a board-certified toxicologist specializing in medical device biocompatibility, toxicological risk assessment, preclinical safety assessment of biomaterials and nano-enabled products, and material-level testing. She has assisted multiple medical device market applications in accordance with European and US Food and Drug Administration (US FDA) guidelines and other global regulations. Prior to joining Gradient, Dr. Diaz-Diestra worked for the US FDA and helped to develop guidelines for the biocompatibility assessment of medical devices incorporating novel materials (e.g., nanomaterials, absorbables). In addition, she was a visiting scientist at the Harvard T.H. Chan School of Public Health, where she was actively involved in research projects centered around nanotoxicology. Dr. Diaz-Diestra is a co-chair of the US Association for the Advancement of Medical Instrumentation (AAMI) Combination Products Committee and convenor of the International Organization for Standardization (ISO) Biological Evaluation of Medical Devices (TC 194) Nanomaterials Working Group (WG 17).
Medical Device Biocompatibility: Provided compliance documentation and support for the EU Medical Device Regulation (MDR), Regulation (EC) No 2017/745, Annex I, General Safety and Performance Requirements (GSPR) 10 for circulating blood devices.
Nano-Enabled Product Safety Evaluation: Developed and conducted biological safety evaluation strategies for nano-enabled medical devices (e.g., silver) for both US and CE submissions. Authored customized biological safety evaluation plans tailored to nano-specific features, recommending material and chemical characterization techniques (e.g., particle size, surface area, morphology, chemical composition) and biological testing to ensure safety and regulatory compliance.
Chemical Equivalency Assessment: Designed and conducted chemical equivalency studies in accordance with ISO 10993-18, Annex C, to support manufacturing changes in prefilled syringes.
Biological Safety Evaluation: Developed and conducted biological safety evaluation strategies for absorbable-based device (510(k)/CE approved). Authored biological safety evaluation plans and reports inclusive of in vivo and in vitro biocompatibility results, chemical characterization evaluations to address device compatibility, toxicological risk assessments, material and manufacturing analyses, and justifications for non-testing.
Biological Safety Assessment and Shelf-Life Evaluation: Developed and conducted biological safety evaluation strategies for intraocular lenses (PMA approved). Authored and reports in compliance with ISO 11979 and ISO 10993, including biocompatibility testing, chemical characterization, toxicological risk assessments, and justifications for non-testing. Conducted shelf-life evaluation following ISO 11979-4 and ISO 10993-17 to ensure stability and biocompatibility over time.
Boehm, RD; Skoog, SA; Diaz-Diestra, D; Goering, PL; Dair, BJ. 2024. “Influence of titanium nanoscale surface roughness on fibrinogen and albumin protein adsorption kinetics and platelet responses.” J. Biomed. Mater. Res. 112(3):373-389. doi: 10.1002/jbm.a.37635.
Diaz-Diestra, DM; Palacios-Hernandez, Liu, Y; Smith, DE; Nguyen, AK; Todorov, T; Gray, PJ; Zheng, J; Skoog, SA; Goering, PL. 2022. “Impact of surface chemistry of ultrasmall superparamagnetic iron oxide nanoparticles on protein corona formation and endothelial cell uptake, toxicity, and barrier function.” Toxicol. Sci. 188(2):261-275. doi: 10.1093/toxsci/kfac058.
Palacios-Hernandez, T; Diaz-Diestra, D; Nguyen, AK; Skoog, SA; Chikkaveeraiah, BV; Tang, X; Wu, Y; Petrochenko, PE; Sussman, EM; Goering, PL. 2020. “Cytotoxicity, cellular uptake and apoptotic responses in human coronary artery endothelial cells exposed to ultrasmall superparamagnetic iron oxide nanoparticles.” J. Appl. Toxicol. 40(7):918-930. doi: 10.1002/jat.3953.
Diaz-Diestra, D; Thapa, B; Badillo-Diaz, D; Beltran-Huarac, J; Weiner, B; Morell, G. 2018. “Graphene oxide/ZnS:Mn nanocomposite functionalized with folic acid as a nontoxic and effective theranostic platform for breast cancer treatment.” Nanomaterials 8(7):484.