(3z) Engineering at the Nano-Bio Interface: Corona-Mediated Nanoparticle Design, from Fundamentals to Functionality

Engineered nanoparticles have recently emerged as a key technology for developing sensing, imaging, and delivery tools to probe and modify biological systems. However, a paramount challenge towards implementing nanoparticle-based technologies remains: how are our engineered nanoparticles affecting, and being affected by, the bioenvironments in which they are applied? Nanotechnologies are largely developed and validated in vitro, devoid of the molecular complexities of in vivo use for which they are intended. Introducing a nanoparticle into a complex biological system leads to the rapid inception of the nano-bio interface, as proteins and other biomolecules spontaneously coat the nanoparticle surface, forming a “biomolecular corona”. Consequences of protein adsorption to nanoparticles are multifold: corona formation unpredictably changes the nanoparticle identity and fate, as the adsorbed proteins mask original surface characteristics and endow new biochemical properties. In turn, protein adsorption often diminishes nanoparticle effectiveness and leads to adverse biocompatibility outcomes. Although formation of the nanoparticle-corona complex challenges our control over its use in nanobiotechnology applications, it concurrently presents a unique opportunity to (1) study and (2) take advantage of the corona as a functional handle to tune auxiliary nanoparticle properties.

Research Experience

During my graduate work at UC Berkeley, my research has centered on studying how biomolecules interact with nanomaterials, with the broad goal of increasing the predictability and efficacy of nanotechnologies applied in biological systems. In Prof. Markita Landry’s lab, I studied protein corona formation on nanoparticle surfaces, with a specific emphasis on carbon nanotube-based sensors in biological environments such as the brain extracellular space. I have mentored students in research and formed collaborations to accomplish the three main branches of my project: characterizing protein corona composition, driving forces, and dynamics. Exploring how biomolecules modulate the inherent characteristics of nanoparticles has been a theme within my research and has led to my following research accomplishments:

1. I optimized a platform to study protein corona formation on nanoparticle surfaces and applied this platform to understand the adsorption of proteins to single-walled carbon nanotube (SWCNT)-based dopamine nanosensors.
2. I developed an assay to measure in-solution exchange dynamics of biomolecules, such as proteins and DNA, on the SWCNT surface.
3. I initiated a collaboration to apply small-angle X-ray scattering (SAXS) to investigate in-solution structural morphology of biomolecule-functionalized SWCNTs.
4. I translated our platform for SWCNT noncovalent biopolymer functionalization to an analogous two-dimensional carbon-based nanomaterial: graphene quantum dots.

My PhD research investigating mechanisms of protein corona formation on nanoparticle-based probes provides the starting point for my independent research program. Additionally, I am involved in a six-member team project through UCLA’s Women in Mathematical Biology program, modeling actin network dynamics by building connected stochastic and continuum models. Working within this team has given me the opportunity to apply and develop my mathematical background that I will use towards my proposed modeling objectives.

Future Research

Engineered nanoparticles remain a distinctly promising technology for developing our knowledge of how biological systems function (through sensing and imaging) and addressing global health challenges (through drug and genetic cargo delivery), despite aforementioned obstacles. I aim to apply rationally designed nanoparticle-based architectures to investigate and provide solutions to pressing biological problems. Nanoparticles possess desirable optical properties and exist at the scale at which fundamental biological processes occur, rendering them ideal candidates with the requisite spatiotemporal resolution to visualize and act upon biological systems. Specifically, nanoparticles will enhance our still limited understanding of the brain, such as in the cause and progression of neurodegenerative diseases. Moreover, nanoparticles offer a route to targeted treatments, relevant for localized diseases in areas such as joints and tumors.

Broadly, nanoparticle architectures consist of two key components: (1) a functional ligand that interacts with the environment, tethered to (2) a nanoparticle foundation that acts as a signal transducer (for sensing), contrast agent (for imaging), or carrier (for delivery). Single-walled carbon nanotubes (SWCNTs) are optimal signal transduction elements for sensing and imaging owing to their photostability, biocompatibility, and emission in the near-infrared region over which biological samples are optically transparent.Towards delivery purposes, SWCNTs offer high surface area ideal for cargo loading and reversible binding modes for cargo unloading. For molecular recognition and targeted delivery applications, proteins exhibit broad functional diversity and confer exquisitely sensitive and selective binding capabilities. I aim to harness these characteristics of proteins, together with SWCNTs as the underlying nanoparticle substrate, and apply rational design techniques to overcome the prior challenges in the field including nanosensor robustness, specificity in targeting and delivery, and a quantitative understanding of how these complex protein-nanoparticle systems function. Accordingly, the objectives of my research are to:

1. Design and develop nanoparticle architectures using a fundamental knowledge of nano-bio interfaces
2. Create corona-mediated nanoparticle systems with stealth polymers, targeting moieties, and controlled release properties that mitigate or promote selective protein adsorption
3. Establish actionable design principles and predictive models for collective interactions at the nano-bio interface of engineered nanoparticles

My lab will employ corona-mediated nanoparticle systems for applications in neuroscience (particularly in understanding Alzheimer’s disease), autoimmunity (rheumatoid arthritis), and oncology (tumor targeting). Although our initial studies will employ SWCNTs, we will translate this work to other nanoparticles and surface coatings, such as biomimetic and zwitterionic. This approach to study life at the nanoscale will deepen our understanding of how biological systems function that in turn improves early disease detection, effective drug design, and eradication of disease course.

Teaching Interests

Beyond the scientific achievements we make in the lab is the impact we have on our students. As a professor, I aim to inspire my students to continue in the pursuit and application of STEM knowledge. Leading students in academic, research, and outreach settings has given me the perspective that being an effective educator is grounded in teaching science with passion and compassion. Additionally, I use my role as a teacher to lead from the front in creating an inclusive classroom in which all students can learn.

My teaching objectives are to instill scientific curiosity in my students and give my students the ability and motivation to pursue answers to scientific questions. I infuse my teaching with inquiry-based learning via problem-solving, either individually, collaboratively in groups, or as a whole class. Active learning engages students in critical thinking and demonstrates how to implement otherwise abstract concepts to tackle tangible questions, thus promoting a deeper knowledge of the material.

Teaching Experience

At UC Berkeley, I have had three teaching opportunities as a Teaching Assistant (TA): Thermodynamics, Biomolecular Engineering (graduate course), and Introduction to Chemical Engineering Design. Based on my teaching performance, I was honored to receive two awards and to be nominated five times to lead effective teaching workshops for incoming engineering TAs. In the lab, I have mentored four women in my research area and numerous junior graduate students within my subgroup. Beyond the scientific community of UC Berkeley, I have led outreach programs in the surrounding Bay Area to foster excitement for science in young and diverse students and empower them to pursue STEM. Specifically, I volunteer as a “Bay Area Scientists in Schools” teacher and have developed a new lesson plan for 2^nd and 3^rd grade public elementary school students to learn about the properties of matter and phase transitions through interactive classroom activities.

Future Teaching

I am enthusiastic to teach any core chemical engineering course at the undergraduate or graduate level, especially thermodynamics and transport phenomena, and elective courses, such as bioengineering and colloids. I am also excited to introduce a new course on nanobiotechnology. Adding a nano-bio course into chemical engineering curriculum is important in inspiring students with challenging, cross-disciplinary questions and demonstrating how engineering concepts can be readily applied towards solving problems within this orthogonal field.

I will engage a broad student body in building a diverse, inclusive lab environment and leading a supportive classroom. As a leader in academia, I will leverage my position, as both a teacher and research mentor, to promote participation of underrepresented minorities in STEM and inspire the next generation of STEM leaders.

Selected Awards

• NSF GRFP
• UW Distinguished Young Scholars Seminar Speaker
• ACS CAS Future Leader
• ACS WCC/Merck Research Award
• CU Boulder ACTIVE Faculty Development and Leadership Intensive
• Excellence in Teaching Award
• Outstanding Graduate Student Instructor Award

Selected Publications

1. Pinals, R. L.*, Yang, D.*, Lui, A., Cao, W., Landry, M. P. Corona Exchange Dynamics on Carbon Nanotubes by Multiplexed Fluorescence Monitoring. JACS 142, 1254–1264 (2020).
2. Pinals, R. L., Yang, D., Rosenberg, D. J. et al. Protein Corona Composition and Dynamics on Carbon Nanotubes in Blood Plasma and Cerebrospinal Fluid. Angew. Chem. (In review, 2020).
3. Pinals, R. L.*, Jeong, S.*, Dharmadhikari, B., et al. Graphene Quantum Dot Oxidation Governs Noncovalent Biopolymer Adsorption. Scientific Reports 10, 1-14 (2020).
4. Pinals, R. , Chio, L., Ledesma, F., Landry, M.P. Engineering at the Nano-Bio Interface: Harnessing the Protein Corona Towards Nanoparticle Design and Function. Analyst DOI: 10.1039/d0an00633e (2020).