About

Eric S.G. Shaqfeh is the Lester Levi Carter Professor and Professor of Mechanical Engineering at Stanford University. His role within the department involves research and teaching in the field of chemical engineering, with a focus on the intersection of mechanical engineering principles and chemical processes. The page indicates his position and title but does not provide specific details about his research focus, background, or key contributions.

Research topics

• Computer Science
• Mechanical engineering
• Artificial Intelligence
• Materials science
• Nanotechnology
• Optics
• Computer hardware
• Geometry
• Composite material
• Physics
• Engineering

Selected publications

• Photopatterned Sacrificial Vascular Architectures for Large Tissue-Scale Oxygenation

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-03-02

  article

  Abstract The engineering of thick, metabolically active tissues is constrained by the lack of scalable methods to create perfusable vasculature. This hinders effective metabolite transport in large tissue volumes, posing a critical barrier for regenerative tissue applications. In this study, we introduce photopatterned Channel Architectures with Sacrificial Templates (pCAST), an additive manufacturing strategy for generating three dimensional (3D), interconnected vascular networks with precisely defined negative space. Water-soluble sacrificial templates were fabricated using scalable Continuous Liquid Interface Production (CLIP), embedded within tissue constructs, and flushed away to yield 50 µm perfusable channels spanning centimeter-scale tissue constructs. We then apply experimental oxygen mapping and viability analysis to pCAST constructs to build finite-element models that predict patterns of oxygen availability and tissue survival are governed by the balance between metabolic demand and vascular architecture, consistent with reaction–diffusion theory. This computational framework quantitatively predicts oxygen distributions and viability boundaries across vascular geometries and is validated experimentally. Together, these results establish pCAST as a scalable design framework linking vascular architecture, perfusion, and metabolic support for engineering large, 3D perfused tissue constructs. Significance The ability to engineer thick, living tissues is limited by poor oxygen and nutrient delivery, which causes cell death before tissues can function or integrate with the body. This work addresses that fundamental barrier by introducing photopatterned Channel Architecture with Sacrificial Templates (pCAST), a scalable manufacturing strategy that creates precisely defined, perfusable vascular networks inside 3D tissues. By combining high-resolution 3D printing, sacrificial templating, and quantitative oxygen mapping, this research establishes design rules that link vascular geometry, perfusion, and tissue viability. These insights provide a general framework for building large, metabolically active tissues, with direct relevance to cardiac patches and other regenerative medicine applications.

  PublisherDOI

• Measuring the properties of a viscoelastic fluid using a tethered swimmer

  Journal of Rheology · 2026-04-29

  articleSenior author

  Viscoelastic normal stresses can generate propulsion in swirlers—axisymmetric swimmers that break fore-aft symmetry and rotate about their axis of symmetry—even in the absence of propulsion in a Newtonian fluid at low Reynolds numbers. In this study, we demonstrate the first measurements of the zero-shear first normal stress coefficient, ψ1,0, and the longest relaxation times, λ1 and λ2, of a viscoelastic fluid using a tethered swirler, simply via measurements of its propulsive force. Through the combined application of microhydrodynamic theory and numerical simulations, we establish transfer functions relating a swirler’s propulsive force to the surrounding fluid’s zero-shear normal stress coefficients and linear viscoelastic spectrum, thereby enabling rheological measurements without viscometric flow. The transfer functions are then applied to experimentally measured propulsive forces to give precise measurements of ψ1,0, λ1, and λ2 of a viscoelastic Boger fluid, for which measurements of ψ1,0 are not achievable on standard benchtop rheometers due to limited sensitivity. Furthermore, for a given fluid, the propulsive force is a function of swimmer and confinement geometry, with the geometric dependence quantitatively predicted by analytical theory and Newtonian fluid simulations. Our work provides a proof of concept of a “tethered swimming rheometer” that not only is capable of measuring both steady and dynamic properties of viscoelastic fluids but also implies a large design space where geometry can be optimized to enhance measurement sensitivity and range.

  PublisherDOI

• Colloidal hydrodynamic interactions in viscoelastic fluid

  ArXiv.org · 2025-08-16

  preprintOpen access

  The motion of suspended colloidal particles generates fluid disturbances in the surrounding medium that create interparticle interactions. While such colloidal hydrodynamic interactions (HIs) have been extensively studied in viscous Newtonian media, comprehensive understanding of HIs in viscoelastic fluids is lacking. We develop a framework to quantify HIs in viscoelastic fluids with high spatiotemporal precision by trapping colloids and inducing translation-rotation hydrodynamic coupling. Using solutions of wormlike micelles (WLMs) as a case study, we discover that HIs are strongly time-dependent and depend on the structural memory generated in the viscoelastic fluid, in contrast to "instantaneous" HIs in viscous Newtonian fluids. We directly measure time-dependent HIs between a stationary probe and a driven particle during transient start-up, developing on the WLM relaxation timescale. Following the sudden cessation of the driven particle, we observe an intriguing flow reversal in the opposing direction, lasting for a time about ten times larger than the WLM relaxation time. We corroborate our observations with analytical microhydrodynamic theory, direct numerical solutions of a continuum model, and particle-based Stokesian dynamics simulations. We find that the structural recovery of the WLMs from a nonlinear strain can generate anisotropic and heterogeneous stresses that produce flow reversals and hydrodynamic attraction among colloids. Measured heterogeneities indicate a breakdown of standard continuum models for constitutive relations when the size of colloids is comparable to the length scales of the polymeric constituents and their entanglement lengths.

  PublisherOA PDFDOI

• Selective molecular gas phase etching in layered high aspect-ratio nanostructures for semiconductor processing. II. Experiments and model validation

  Journal of Vacuum Science & Technology A Vacuum Surfaces and Films · 2025-01-01 · 3 citations

  articleSenior author

  A simulation model for selective molecular gas etching in nanostructures has been described in Paper I [Z. Zajo et al. J. Vac. Sci. Technol. A 43, 013006 (2025)], in which the transport of molecules was modeled as Knudsen diffusion in the free-molecular flow regime and the surface reactions were modeled using (i) a simple linear model and (ii) a Langmuir adsorption based model. In this paper, we complete experiments on etching of stacked SiGe-Si structures by molecular F2 and compare the results of experiments and the predictions from the model mentioned above. The results of our investigation show that the transport of F2 in the nanostructures is in the nearly total re-emission regime for the range of process parameters and length scales involved in our experiments and that only a very small fraction of the incoming F2 flux reacts with SiGe. This is evidenced by the small values of estimated sticking coefficients on SiGe (∼10−6–10−3) from the linear model as well as the small values of the reaction rate constant on SiGe relative to the F2 flux on an open surface, k2/J (∼10−7–10−4) with the exact value being dependent on Ge% and the temperature at which the etching is performed. This enables the achievement of uniform etch rates across all layers in highly stacked nanostructures as required in the fabrication of gate-all-around nanotransistors. We also estimate the surface reaction rate constants as well as the activation energies as a function of Ge% for SiGe etching by F2, and the results are consistent with the observed Ge composition dependence of etch selectivity of SiGe over Si.

  PublisherDOI

• Selective molecular gas phase etching in layered high aspect-ratio nanostructures for semiconductor processing. I. Modeling framework and simulation

  Journal of Vacuum Science & Technology A Vacuum Surfaces and Films · 2025-01-01 · 2 citations

  articleSenior author

  The need for precise control of nanoscale geometric features poses a challenge in manufacturing advanced gate-all-around nanotransistors. The high material selectivity required in fabricating these transistors makes thermal gas etching much more appealing in comparison to liquid phase and plasma-based etching techniques. The selective thermal etching by F2 of silicon–germanium (SiGe) stacks comprised of alternating layers of silicon (Si) and SiGe is explored in this context for semiconductor manufacturing applications. We propose and develop computer simulations as a tool to predict the etch profile evolution over time in such an etching process. The tool is based on a mathematical model that considers the transport processes and surface interactions involved in the gas phase etching process—which at the nanoscale is primarily Knudsen diffusion in the free molecular flow regime. Thus, the transport model is formulated as a boundary integral equation, which takes into account the direct flux of etchant molecules that any given point on the exposed surface receives from the bulk gas phase as well as the re-emission flux from other parts of the structure itself. We compared the applicability of two different surface reaction models—a model where the local etch rate is linear in the flux at a point and a Langmuir adsorption/reaction model—to connect the net flux received at a point on the surface to the local etch rate. This paper precedes Paper II of this series, which describes the experimental methods and comparison with model predictions of F2 etching in high aspect ratio Si–SiGe stacked nanostructures.

  PublisherDOI

• Colloidal hydrodynamic interactions in viscoelastic fluids

  Soft Matter · 2025-01-01

  article

  The motion of suspended colloidal particles generates fluid disturbances in the surrounding medium that set up interparticle interactions. While such colloidal hydrodynamic interactions (HIs) have been extensively studied in viscous Newtonian media, comprehensive understanding of HIs in viscoelastic fluids is lacking. We develop a framework to quantify HIs in viscoelastic fluids with exquisite spatiotemporal precision by trapping colloids and inducing translation-rotation hydrodynamic coupling. Using solutions of wormlike micelles (WLMs) as a case study, we discover that HIs are strongly time-dependent and depend on the structural memory generated in the viscoelastic fluid, in contrast to "instantaneous" HIs in viscous Newtonian fluids. We directly measure "time-dependent" HIs between a stationary probe and a driven particle during transient start-up, developing on the WLM relaxation timescale. Following the sudden cessation of the driven particle, we observe an intriguing flow reversal in the opposing direction, lasting for a time 10× larger than the WLM relaxation time. We corroborate our observations with analytical microhydrodynamic theory, direct numerical solutions of a continuum model, and particle-based Stokesian dynamics simulations. We find that the structural recovery of the WLMs from a nonlinear strain can generate anisotropic and heterogeneous stresses that produce flow reversals and hydrodynamic attraction among colloids. Measured heterogeneities indicate a breakdown of standard continuum models for constitutive relations when the size of colloids is comparable to the length scales of the polymeric constituents and their entanglement lengths.

  PublisherDOI

• Methods for modeling and real-time visualization of CLIP and iCLIP-based 3D printing

  Giant · 2024-01-12 · 8 citations

  articleOpen access

  Resin 3D printing is experiencing greater adoption in real-world fabrication settings for both prototyping and manufacturing. To optimize the speed of these fabrication methods, few techniques for predicting and visualizing such processes, and its variants, in real-time have been proposed and rigorously evaluated. In this work we outline and validate two complementary methods to monitoring resin 3D printing, specifically continuous liquid interface production (CLIP), in real-time for optimal print parameter selection. Namely, we use: (1) a load cell mounted on the build platform capable of measuring tensile forces during printing, and (2) our novel approach to optical coherence tomography scanning aligned with the printer resin vat. After describing our technical implementation of each of these strategies below, we assess the benefits of each in turn, and evaluate their relative limitations.

  PublisherDOI

• Growing three-dimensional objects with light

  Proceedings of the National Academy of Sciences · 2024-07-01 · 26 citations

  articleOpen access

  Vat photopolymerization (VP) additive manufacturing enables fabrication of complex 3D objects by using light to selectively cure a liquid resin. Developed in the 1980s, this technique initially had few practical applications due to limitations in print speed and final part material properties. In the four decades since the inception of VP, the field has matured substantially due to simultaneous advances in light delivery, interface design, and materials chemistry. Today, VP materials are used in a variety of practical applications and are produced at industrial scale. In this perspective, we trace the developments that enabled this printing revolution by focusing on the enabling themes of light, interfaces, and materials. We focus on these fundamentals as they relate to continuous liquid interface production (CLIP), but provide context for the broader VP field. We identify the fundamental physics of the printing process and the key breakthroughs that have enabled faster and higher-resolution printing, as well as production of better materials. We show examples of how in situ print process monitoring methods such as optical coherence tomography can drastically improve our understanding of the print process. Finally, we highlight areas of recent development such as multimaterial printing and inorganic material printing that represent the next frontiers in VP methods.

  PublisherDOI

• The effects of suspending fluid viscoelasticity on the mechanical properties of capsules and red blood cells in flow

  Journal of Non-Newtonian Fluid Mechanics · 2024-02-28 · 4 citations

  articleSenior author
  PublisherDOI

• High-resolution stereolithography: Negative spaces enabled by control of fluid mechanics

  Proceedings of the National Academy of Sciences · 2024-09-04 · 12 citations

  articleOpen access

  Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of ultraviolet dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z-axis resolution. We demonstrate the ability to resolve 50-μm microchannels, breaking the historical relationship between resin properties and negative space resolution. With this approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties.

  PublisherDOI

Recent grants

• The Dynamics of Curved Fluid Films Between Complex Interfaces

  NSF · $345k · 2020–2025

• Collaborative Research: Understanding the Collective Effects in Suspensions of Vesicles, Capsules, and Particles

  NSF · $225k · 2011–2015

• Swirling Propulsion in Complex Fluids and Micro-Swimming Rheometry

  NSF · $447k · 2022–2027

• The Rheology of Complex Suspensions In Viscoelastic Suspending Fluids

  NSF · $300k · 2018–2021

• Sedimenting Particulate Suspensions in Viscoelastic Fluids Under Shear

  NSF · $359k · 2013–2017

Frequent coauthors

• Gianluca Iaccarino

  42 shared

• Yves Dubief

  22 shared

• Olaf Marxen

  20 shared

• Thomas C. B. Kwan

  University of California, Santa Barbara

  18 shared

• Parviz Moin

  Stanford University

  18 shared

• Matthew Tirrell

  Argonne National Laboratory

  16 shared

• Phillip Schorr

  IFP Énergies nouvelles

  16 shared

• Vincent Terrapon

  16 shared

Education

• Ph.D., Chemical Engineering

  Stanford University

  1990

• M.S., Chemical Engineering

  Stanford University

  1986

• B.S., Chemical Engineering

  University of California, Berkeley

  1984

Awards & honors

• APS Francois N. Frenkiel Award (1989)
• NSF Presidential Young Investigator Award (1990)
• David and Lucile Packard Fellowship in Science and Engineeri…
• Camile and Henry Dreyfus Teacher--Scholar Award (1994)
• W.M. Keck Foundation Engineering Teaching Excellence Award (…