About

Professor Robert J. Macfarlane is a Richard P. Simmons (1953) Professor in Metallurgy and an Associate Professor of Materials Science and Engineering at MIT. His research focuses on building new materials using concepts and building blocks from supramolecular chemistry, polymer science, nanotechnology, self-assembly, colloids, and processing science. In his lab, researchers have developed design principles for synthesizing hierarchically organized materials with simultaneous and programmed control of structural features across molecular, nano, micro, and macroscopic length scales. These nanocomposites enable fundamental insights into mechanical, optical, chemical, electrical, and thermal structure-property relationships and are applied in areas such as adhesives, coatings, sensors, electronic and optical devices, and energy storage. Professor Macfarlane earned a BA in biochemistry from Willamette University in 2004, an MS in chemistry from Yale University in 2006, and a PhD in chemistry from Northwestern University in 2013, where he developed design rules for DNA-programmed assembly of nanoparticle superlattices. Following his doctorate, he was awarded the Kavli Nanoscience Institute Postdoctoral Fellowship at Caltech, where he developed self-assembly and processing methods to synthesize bottlebrush polymer photonic crystals. Since joining MIT's Department of Materials Science and Engineering in 2015, he has merged his assembly techniques to establish novel synthesis, assembly, and processing routes for scalable, compositionally versatile, and hierarchically organized nanocomposites. His work has earned him several awards, including the 2019 Non-Tenured Faculty Award from 3M, the 2017 Unilever Award for Outstanding Young Investigator in Colloid and Surfactant Science, the 2017 NSF Faculty Early Career Development Award, the 2016 Young Investigator Award from the Air Force Office of Scientific Research, and the 2010 Outstanding Researcher Award from the International Institute for Nanotechnology.

Research topics

• Materials science
• Nanotechnology
• Composite material
• Chemistry
• Computer Science
• Optoelectronics
• Chemical engineering
• Crystallography

Selected publications

• CHARIOT-AAV: Conjugation of diverse vectors to adeno-associated viruses for delivery of large genes

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-04-15

  articleOpen access

  Systemic, tissue-specific delivery of large transgenes exceeding the packaging capacity of adeno-associated viruses (AAVs) remains a key translational challenge for molecular therapeutics. Vectors with larger capacities, such as lentiviral vectors (LVVs) and lipid nanoparticles (LNPs), often lack adjustable, tissue-specific tropisms. Here we report CHARIOT-AAV (Crosslinked Hybrid Architectures for Robust, Interchangeable, and Organ-specific Targeting with AAV), a platform where diverse delivery vectors are conjugated to AAVs, thereby achieving tissue-specific tropism of AAVs and expanded cargo capacity. AAV-AAV conjugates packaging split SpCas9 constructs in AAV.CAP-B10 capsids demonstrate a ~2-fold increase in brain gene editing efficiency over unconjugated AAV cocktails after intravenous injection. In addition to AAV-AAV conjugates, AAV-LVV and AAV-LNP conjugates achieve AAV-guided delivery of genetic payloads to target cells. Furthermore, AAV-LNP conjugates enable systemic delivery of mRNAs to brain endothelial cells. CHARIOT-AAV thus provides a modular platform for systemic, tissue-specific delivery of diverse therapeutics beyond the limits of individual vectors.

  PublisherOA PDFDOI

• Low Symmetry Nanoparticle Superlattices via Spontaneous Valency

  ChemRxiv · 2026-03-03

  articleOpen accessSenior author

  In colloidal self-assembly, particle valency is controlled through the use of specific particle shapes or surface functionalization anisotropy. Although spheres are typically the easiest particle shape to produce, their inability to produce directional bonding limits their structures to densely packed, high symmetry unit cells. Here, we present an alternative route towards lower-symmetry lattice formation: isotropic, soft nanoparticles that undergo spontaneous symmetry breaking during the assembly process. This in-situ asymmetry generation, enabled by the recruitment of flexible electrostatic chain ends to the interfaces between nanoparticles, leads to an effective valency which determines final lattice structure. Combined with evidence from molecular dynamics simulations, we use a series of CsCl-, Th 3 P 4 -, and NaCl-type lattices assembled from identical but oppositely charged nanoparticles to elucidate the relationship between nanoparticle core size, polymer graft length, and resulting lattice coordination. We also report the first use of wide-angle x-ray scattering to confirm the recruitment and alignment of polymer chains at nanoparticle-nanoparticle interfaces, and assemble the first experimentally realized CaF 2 -and 𝛽-UH 3 -type nanoparticle superlattices. Together, this work demonstrates a potentially new paradigm in nanoparticle superlattice engineering, opening additional and more accessible routes towards low-symmetry and low-packing density structures.

  PublisherDOI

• Breaking Symmetry in Nanoparticle Superlattices via Spontaneous Valency

  ChemRxiv · 2026-05-18

  articleSenior author

  Nanoparticle superlattices enable programmable material structure through ligand-mediated interactions, but attractive ligand interactions typically limit assembly to densely packed lattices that maximize nearest neighbor bonding. Intentionally programmed directional bonding and valency are therefore typically assumed to require particle-level anisotropy in shape or surface patterning. Using assemblies of flexible isotropic nanoparticles, we show here that valency need not be encoded by particle geometry, but can instead emerge spontaneously during assembly. When ligand coronas are sufficiently deformable, ligands reorganize to align along interparticle interfaces, generating an effective valency. Using a combination of experiment and simulation, we show that increasing ligand deformability lowers lattice coordination numbers, and are able to establish design principles for assembling isotropic building blocks into lattices with lower coordination, packing density, and symmetry than would be predicted from hard-sphere packing. The work presented here therefore establishes ligand flexibility as a design parameter for programming coordination in nanoparticle assembly.

  PublisherDOI

• Redistribution of Ru in Fe₂O₃–Ru Nanocatalysts through an Oxidative Pretreatment Improves Reverse Water–Gas Shift Activity

  ACS Applied Nano Materials · 2025-07-24

  article

  We have synthesized Fe–Ru nanoparticles via a solvothermal method to create catalysts for the reverse water–gas shift reaction and demonstrated the impact of reductive and oxidative pretreatments on both catalytic performance and structure. Catalytic testing showed improved activity after exposure to O2 at 600 °C. In contrast, the activity became lower if then exposed to H2 at 600 °C. Environmental scanning transmission electron microscopy and scanning electron microscopy showed that exposure to O2 at 600 °C changes the morphology and completely oxidizes Fe into Fe2O3. Exposure to H2 at elevated temperature caused Ru coalescence at the surface of the nanoparticle, forming clusters which decreased the optimization of Ru. Reoxidation of the particles exposed to H2, however, caused a redistribution of Ru that appears beneficial in maximizing Ru exposure and synergy with Fe oxide, with no major changes in the morphology and oxide structure. Our diagnostics demonstrate the complex and reversible rearrangements possible in these multicomponent particles and the benefits of oxidative pretreatment to enhance or regenerate Fe–Ru catalysts in other important catalytic reactions such as Fischer–Tropsch synthesis.

  PublisherDOI

• 33 Unresolved Questions in Nanoscience and Nanotechnology

  ACS Nano · 2025-09-04 · 22 citations

  articleOpen access

  Significant advances in science and engineering often emerge at the intersections of disciplines. Nanoscience and nanotechnology are inherently interdisciplinary, uniting researchers from chemistry, physics, biology, medicine, materials science, and engineering. This convergence has fostered novel ways of thinking and enabled the development of materials, tools, and technologies that have transformed both basic and applied research, as well as how we address critical societal challenges. In this Nano Focus, we pose and explore 33 questions whose answers could profoundly impact fields such as energy, electronics, the environment, optics, and medicine. These questions highlight the need for deeper foundational understanding, improved tools and techniques, and innovative applications─each with significant societal relevance. Together, they represent a global call-to-action for the scientific community.

  PublisherOA PDFDOI

• DNA origami directed nanometer-scale integration of colloidal quantum emitters with silicon photonics

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-01-26 · 1 citations

  preprintOpen access

  Abstract Incorporation of colloidal quantum emitters into silicon-based photonic devices would enable major advances in quantum optics. However, deterministic placement of individual sub-10 nm colloidal particles onto micron-sized photonic structures with nanometer-scale precision remains an outstanding challenge. Here, we introduce Cavity-Shape Modulated Origami Placement (CSMOP) that leverages the structural programmability of DNA origami to precisely deposit colloidal nanomaterials within lithographically-defined resist cavities. CSMOP enables clean and accurate patterning of origami templates onto photonic chips with high yields. Soft-silicification-passivation stabilizes deposited origamis, while preserving their binding sites to attach and align colloidal quantum rods (QRs) to control their nanoscale positions and emission polarization. We demonstrate QR integration with photonic device structures including waveguides, micro-ring resonators, and bullseye photonic cavities. CSMOP therefore offers a general platform for the integration of colloidal quantum materials into photonic circuits, with broad potential to empower quantum science and technology.

  PublisherOA PDFDOI

• Forging Nanoparticle Superlattices with Colloidal Metallurgy

  ACS Nano · 2025-05-31 · 2 citations

  articleSenior authorCorresponding

  Nanoparticle superlattices present transformative opportunities for material design by enabling precise control over both nanoscale organization and composition; however, translating these assemblies into macroscopic constructs while preserving nanoscale order remains a critical challenge due to the incompatibility of traditional processing techniques with colloidal systems. This study introduces "colloidal metallurgy," a framework for understanding and controlling defect evolution and densification in nanoparticle superlattices during colloidal sintering. We investigate the effects of pressure and temperature to elucidate mechanisms of particle transport, defect annealing, and densification as single-crystal colloidal assemblies coalesce into polycrystalline superlattices. Pressure-driven crystallite fracture is identified as the primary mode of densification, while temperature enhances particle mobility, enabling defect reduction and grain growth. A multistage sintering strategy employing high temperature annealing to grow grains and restore fracture-based capacity for densification was developed to produce dense (∼1% porosity) polycrystals with low defect counts, demonstrating a pathway for processing nanoparticle superlattices. By exploring the parallels and distinctions between atomic and colloidal sintering, this work establishes critical insights into the mechanisms governing colloidal material processing. These findings lay the groundwork for defect engineering in colloidal systems, offering a scalable approach to design macroscopic materials with tailored properties.

  PublisherDOI

• 33 Unresolved Questions in Nanoscience and NanotechnologyArticle link copied!

  RWTH Publications (RWTH Aachen) · 2025-01-01

  article
  Publisher

• Modeling the role of supramolecular clustering in multivalent assembly

  Soft Matter · 2025-01-01 · 2 citations

  articleOpen accessSenior author

  , the probability of a pair being bound is unaffected by the bound state of neighboring pairs. Inspired by recent experimental work, we report that for a variety of systems this assumption may not hold, leading to the formation of clusters at the binding interface. Through a series of analytical and numerical models of end-functionalized brushes, we reveal the role of cluster size on binding thermodynamics, detail how entropic contributions from polymer chains provide tunable control of cluster size, and provide predictions for cluster size as a function of system architecture. Investigation of these models yields surprising results: within the melting window, the enthalpy of binding of multivalent interfaces is predicted to depend only on cluster size and not on the overall valency of the multivalent system. Moreover, clustering is predicted to be significant even in systems with only weak dipole and dispersion interactions between neighboring groups. Combined, this work brings to light the potential impacts of clustering on multivalent self-assembly, providing theoretical justification for previous experimental observations and paving the way for future work in this area.

  PublisherOA PDFDOI

• Adeno-associated viruses escort nanomaterials to specific cells and tissues

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-04-09 · 1 citations

  preprintOpen access

  Abstract The delivery of nanotherapeutics to specific tissues relies on bespoke targeting strategies or invasive surgeries. Conversely, adeno-associated viruses (AAVs) can target specific tissues following intravenous injections. Here we show that cell-targeting properties of AAVs could be broadly conferred to nanomaterials. We develop a strategy to couple AAV capsids to nanoparticles that is invariant of viral serotype or nanomaterial chemistry and permits control over stoichiometry of the AAV-nanoparticle chimeras. The chimeras selectively escort nanoparticles into cell classes governed by AAV serotypes. When applied to magnetic nanoparticles, the AAV-nanoparticle chimeras enable magnetically localized gene delivery. In vivo, we show that leveraging the brain-targeting AAV serotype CAP-B10 achieves nanoparticle delivery to the parenchyma with ∼10% efficiency (% injected dose/g [brain] ) while avoiding accumulation in the liver. The enhanced delivery efficiency and tissue specificity highlight the potential of AAV-chimeras as a versatile strategy to escort broad classes of nanotherapeutics to the brain and beyond.

  PublisherOA PDFDOI

Recent grants

• CAREER: Nanocomposite Structure Control via Nanoparticle Self-Assembly

  NSF · $702k · 2017–2022

• Brush Particle-Based Building Blocks for High Refractive Index Composites

  NSF · $450k · 2022–2025

• Fundamental Principles of Multivalency in Nanoscale and Macromolecular Systems

  NSF · $537k · 2023–2026

Frequent coauthors

• Chad A. Mirkin

  Northwestern University

  118 shared

• Byeongdu Lee

  Argonne National Laboratory

  52 shared

• Andrew J. Senesi

  40 shared

• Matthew R. Jones

  Rice University

  38 shared

• Youngeun Kim

  26 shared

• Paul A. Gabrys

  Massachusetts Institute of Technology

  25 shared

• Evelyn Auyeung

  Dow Chemical (United States)

  24 shared

• Mary Wang

  Universidad Católica de Santa Fe

  19 shared

Awards & honors

• 2019 Non-Tenured Faculty Award, 3M
• 2017 Unilever Award for Outstanding Young Investigator in Co…
• 2017 Faculty Early Career Development Award, National Scienc…
• 2016 Young Investigator Award, Air Force Office of Scientifi…
• 2010 Outstanding Researcher Award, International Institute f…