Bio

William (Memo) Carpenter got his first taste of research as an undergraduate at UC
Berkeley (2009-2013) working in the lab of Professor Rich Saykally to study ion
speciation at the air-water interface. William then pursued his PhD at the University of
Chicago (2014-2020) in the lab of Professor Andrei Tokmakoff, where he developed
two-dimensional infrared (2DIR) spectroscopy experiments to study the structures and
dynamics of the common but mysterious aqueous proton H+(aq). His experiments
uncovered direct spectroscopic fingerprints of proton hopping between water molecules
and connected these hops to the collective hydrogen-bonding dynamics of the solution.
Upon graduation, William began his postdoctoral fellowship in the lab of W.E. Moerner
at Stanford, monitoring individual biological nanocontainers in a solution-phase anti-
Brownian trap. These experiments simultaneously probed various chemical and
physical properties of these single objects, such as internal redox chemistry and single-
particle masses for improved models of the assembly and function of these objects.
William will open his lab in August 2024, incorporating advanced molecular
spectroscopy into single-particle observation for fundamental research on new
nanoparticles used for biomedical and sustainability science.

Research Overview

Our group will focus on fundamental relationships between the chemical and physical
properties of nanoparticles made from biological building blocks. As these nanoparticles
are made of molecules like proteins or lipids, they are self-assembled by many weak
noncovalent interactions, but they ultimately form singular objects. This leads us to ask
many questions about their assembly and molecular behavior, such as:

• How do molecular contacts and chemical environment influence physical
  properties like cargo loading and density?
• Conversely, how does the physical assembly affect access to internalized cargo
  such as enzymes?
• What principles do biological nanocontainers use that we could apply to drug
  delivery or generating specific molecules?

• How can we measure these effects on a benchtop microscope?

  
  A key piece in studying these objects is that they can be highly heterogeneous in their
  properties: each object is different in terms of aspects like their size, stoichiometry, and
  molecular arrangement within the particle, which means that we need to observe these
  various properties simultaneously on single members in the population. Our group will
  be developing sensitive single-particle observation techniques such as anti-Brownian
  trapping, single-molecule spectroscopy, and cryo-electron microscopy to determine
  relationships between the various properties in these soft nanoparticle systems. These
  methods will allow us to observe single objects with unprecedented detail and inspire
  new strategies for designing next-generation biomolecular nanoparticles.

Publications

A full list can be found on my Google Scholar Profile:

WB Carpenter, A Mahata, K Vaibhav, and V Gopalan, “Illuminating spatial, dynamic, and chemical complexity in condensates,” Trends Chem, 2026, DOI: 10.1016/j.trechm.2026.04.002.

AA Lavania and WB Carpenter, “Sizing single trapped nanoparticles with interferometric scattering fluctuations,” Phys. Chem. Chem. Phys,2026, 28, 9932.

WB Carpenter, AA Lavania, AH Squires, and WE Moerner, “Label-Free Anti-Brownian Trapping of Single Nanoparticles in Solution,” J. Phys Chem. C, 2024, 128, 20275.

JH Hack, NHC Lewis, S Knight, WB Carpenter, L De Marco, K Ramasesha, and A Tokmakoff, “Generation and Implementation of Continuum Infrared Pulses for Broadband Detection in 2D IR Spectroscopy,” J. Phys. Chem. A, 2024, 128, 4901.

WB Carpenter, AA Lavania, JS Borden, LM Oltrogge, D Perez, PD Dahlberg, DF Savage, and WE Moerner, “Monitoring physical and chemical properties of individual carboxysomes trapped in solution,” Proc. SPIE Optical Trapping and Optical Micromanipulation XX, 2023,12649, 4.

JH Hack, NHC Lewis, WB Carpenter, and A Tokmakoff, “Amplification of mid-IR continuum for broadband 2D IR spectroscopy,” Opt. Lett, 2023, 48, 960.

WB Carpenter, AA Lavania, JS Borden, LM Oltrogge, D Perez, PD Dahlberg, DF Savage, and WE Moerner, “Ratiometric Sensing of Redox Environments Inside Individual Carboxysomes Trapped in Solution,” J. Phys. Chem. Lett. 2022, 13, 4455.

AA Lavania, WB Carpenter, LM Oltrogge, D Perez, JB Turnsek, DF Savage, and WE Moerner, “Exploring masses and internal mass distributions of single carboxysomes in free solution using fluorescence and interferometric scattering in an anti-Brownian trap,” J. Phys. Chem. B, 2022, 126, 8747.