Dr. Daysi Diaz-Diestra is a Board-Certified Toxicologist with academia, industry, and US FDA experience. Her expertise encompasses medical device biocompatibility, toxicology, chemical risk assessment, and material/chemical characterization.

Dr. Diaz-Diestra received her PhD in Physical Chemistry at the University of Puerto Rico-Rio Piedras. Her doctoral research focused on the development of sensing and drug delivery platforms based on functional engineered nanomaterials. She completed her postdoctoral training at the US FDA where she led regulatory projects oriented towards the biocompatibility assessment of nano-enabled medical devices. She continued her postdoctoral work at the University of North Carolina Chapel Hill leading projects aimed at developing gene therapy formulations utilizing lipid nanoparticles, with a focus on applications in vaccination for cancer immunotherapy and infectious diseases.

Dr. Diaz-Diestra is an active member of the Medical Device and Combination Product Specialty Section (MDCPSS) and the Society of Toxicology (SOT). She has organized two workshop sessions focused on the discussion of existing challenges in biocompatibility assessment of absorbable based medical devices, which were held during the 2023 and 2024 SOT Annual Meetings. She also serves as the AAMI BE-WG17 – Nanomaterials Working Group Co-Chair, where she is leading efforts to work on development and recognition of standards related to biocompatibility evaluation of nano-enabled medical devices.

CORE COMPETENCIES

• Developing biological evaluation plans and reports for the assessment of biological safety of medical devices in compliance with the ISO guidance documents for regulatory submissions
• Developing toxicological risk assessments of extractables/leachables testing on medical devices in compliance with the ISO guidance documents for regulatory submissions
• Developing gap analysis documents to ensure previously performed biocompatibility studies comply with the most the recent regulatory requirements and provide biological significance of differences that may be observed
• Working knowledge of FDA and EU MDR regulation expectations along with other global medical device regulations
• Interacting with clients on technical issues related to biocompatibility and chemistry testing
• Subject Matter Expert in biological and toxicological evaluation of nano-enabled medical devices and combination products
  • NAMSA’s primary liaison to US AAMI nanomaterials working group 17, cochair of the US AAMI nanomaterials working group 17, as well as primary voter in US AAMI CP – Combination Products Committee
• Experienced independent researcher in the design and evaluation of nano-based materials for therapeutic applications, including drug delivery systems, gene therapy, controlled release of biomolecules, and cancer immunotherapy
• Skilled in chemical and material characterization techniques:
  • Transmission Electron Microscopy
  • Scanning Electron Microscopy
  • Inductively Coupled Plasma Mass Spectroscopy X-Ray Photoelectron Spectroscopy
  • Fourier Transform Infrared Spectroscopy
  • Gas Chromatography Mass Spectrometry
  • Dynamic Light Scattering
  • Fluorescence
  • UV-Vis
  • Employing in-vitro, ex-vivo, and in-vivo toxicological methodologies for safety evaluation of biomaterials (including nano-based)

RECENT PROJECTS

• Developed a biocompatibility test plan for a nano-enabled oncology therapeutic device and communicate with the FDA during interactive review
• Provided scientific support for a client during communication with the FDA to address biocompatibility related deficiencies for a dental device using silver nanoparticles
• Assisted a European client with customized chemical characterization and biological evaluation plan for nano-polymer matrix intended to be used in an orthopedic application
  • Advised client on resolving challenging issues, including regulatory deficiency and equivocally test, identified during the safety evaluation of medical device
• Addressed equivocal results related to an absorbable based implant through root-cause analysis

PUBLICATIONS (SELECTED)

• Ryan D. Boehm, Shelby A Skoog, Daysi Diaz-Diestra, Peter L Goering, Benita J Dair. “Influence of titanium nanoscale surface roughness on fibrinogen and albumin protein adsorption kinetics and platelet responses” J Biomed Mater Res. 2024; 112(3): 373-389. doi:10.1002/jbm.a.37635

• Daysi M Diaz-Diestra, Teresa Palacios-Hernandez, Yizhong Liu, Diane E Smith, Alexander K Nguyen, Todor Todorov, Patrick J Gray, Jiwen Zheng, Shelby A Skoog, Peter L Goering, “Impact of Surface Chemistry of Ultrasmall Superparamagnetic Iron Oxide Nanoparticles on Protein Corona Formation and Endothelial Cell Uptake, Toxicity, and Barrier Function” Toxicological Sciences, 2022, 188 (2), 261–275, https://doi.org/10.1093/toxsci/kfac058
• Nagarjun Venkata Konduru, Karen Velasco-Alzate, Sitaramaraju Adduri, Kyryl Zagorovsky, Daysi Diaz- Diestra, Faisalina Fisol, Marcelo Sanches, Harrison Ndetan, Joseph David Brain, Ramon Morales Molina. “Pulmonary fate and consequences of transferrin-functionalized gold nanoparticles” Nanotheranostics, 2021, 5 (3), 309-320. doi: 10.7150/ntno.47734.
• Teresa Palacios-Hernandez, Daysi Diaz-Diestra, Alexander K. Nguyen, Shelby A. Skoog, Bhaskara Vijaya Chikkaveeraiah, Xing Tang, Yong Wu, Peter E. Petrochenko, Eric M. Sussman, Peter L. Goering. “Cytotoxicity, Cellular Uptake and Apoptotic Responses in Human Coronary Artery Endothelial Cells Exposed to Ultrasmall Superparamagnetic Iron Oxide Nanoparticles.” Journal of Applied Toxicology, 2020,40 (7), 918-930. https://doi.org/10.1002/jat.3953
• Daysi Diaz-‐Diestra, et “Graphene oxide/ZnS:Mn nanocomposite functionalized with folic acid as a nontoxic and effective theranostic platform for breast cancer treatment”. Nanomaterials 2018, 8(7), 484.
• Daysi Diaz-Diestra, et al. “L-cysteine capped ZnS:Mn quantum dots for room-temperature detection of dopamine with high sensitivity and selectivity”. Biosensors and Bioelectronics, 2017, 87 (15), 693-700.
• Daysi Diaz-Diestra, et al. “Biocompatible ZnS:Mn quantum dots for reactive oxygen generation and detection in aqueous media”. Journal of Nanoparticle Research 2015, 17(12), 461. FEATURED IN: World Biomedical Frontiers, New Tech (2016) 8, 1-2.