Ke Xu Group

We are an interdisciplinary lab that develops new physicochemical tools to interrogate biological, chemical, and materials systems at the nanoscale with extraordinary resolution, sensitivity, and functionality. To do so, we take a multidimensional approach that integrates advanced microscopy, spectroscopy, cell biology, and nanotechnology.


Congratulations to Megan

Congratulations to Megan for winning an Arnold O. Beckman Postdoctoral Fellowship! [Link]

"There is no satisfactory substitute for excellence." -Arnold O. Beckman

Net charge-driven protein interactions and our new review article

With SMdM, we recapitulate in vitro the overlooked role of electrostatic attraction in protein interactions in the predominantly negatively charged intracellular environment. [Link]

See also our new review article on single-molecule and super-resolution mapping of physicochemical parameters, which enables this and many other fascinating studies. [Link]

Congratulations to Alex, Megan, Changdong, and the team!

Seeing nanoaggregates at biomolecular condensate surfaces

With an arsenal of multidimensional/multifunctional super-resolution tools, we unveil nanoscale amyloid aggregates at the surface of FUS condensates formed through liquid-liquid phase separation (LLPS). [Link] [Cover]

Congratulations to Changdong and the team! A great synergy of multidimensional super-resolution methods!


Congratulations to Ha and the team on two papers, direct extraction of single-molecule diffusivity [Link] and size-dependent diffusivity in expandable hydrogels [Link].

Congratulations to Tyler for winning an NSF Fellowship!

Congratulations to Alex and the team for another JACS paper! [Link]

Single-molecule displacement mapping: new insights into in-cell diffusion

Positive, but not negative, net charges impede the intraorganellar diffusion of proteins. [Link]

Unhindered intracellular diffusion of small (<~1 kDa) solutes: mapping diffusivity at up to 250 um2/s in live cells! [Link]

Congratulations to Alex, Limin, and the team!

Why is an ER tubule like an ER sheet?

STORM unveils a striking structural dichotomy of ER tubules in mammalian cells, and fast multicolor imaging shows how the two distinct tubule forms dynamically interconvert in the living cell. [Link]

Congratulations to Bowen and the team! Another tour de force!

Dynamic blistering of graphene

Another fascinating discovery enabled by interference reflection microscopy (IRM). Substrate-supported graphene blisters dynamically in acids -and behaves as a semipermeable membrane! [Link] [Cover]

Congratulations to Yunqi and the team!

A key null result

By showing no enhanced diffusion in enzymatic reactions, we also define the achievable precision for diffusivity from single-molecule displacement statistics. [Link]

Congratulations to Alex and the team!

t-ERGIC: A SURF4 expressway for ER-to-Golgi transport

Following an unexpected discovery of tubular ERGIC, we elucidate a fascinating system that selectively expedites the ER-to-Golgi transport of SURF4 cargos. [Link]

Congratulate Rui for leading this tour de force and Kun and Bowen for the teamwork. I feel we all become better biologists through this journey!

New strategy for STORM dyes

With a very chemistry title, our new paper [Link] introduces a new strategy for high-performance STORM dyes. Highly recommended to anyone trying to achieve optimal results beyond the good old red-excitation window.

Congratulations, Bowen and Michael! Thanks go to our collaborators at Biotium.

Single molecules are your quanta

Our Perspective article in ACS Nano [Link] reflects on the underlying philosophy of how diffraction-unlimited pictures containing rich spatial and functional information emerge through the local accumulation of single-molecule measurements. This is an exciting field, and we hope we achieved our goal of making it understandable to all.

Congratulations to Limin and Kun. We thank all past and current lab members for contributing to related work!

A new approach for fast spectral microscopy

Fed up with the challenges of dispersing the emission spectrum for spectral microscopy? See how we achieved highly multiplexed fluorescence imaging for both multi-targets and biosensing by scanning the excitation wavelength instead! [Link]

Congratulations, Kun, Rui, and Limin!

Cell biology & microscopy

See our new BioRxiv posts, focusing on membrane-trafficking biology [Link] and spectral microscopy [Link], respectively. More details to follow after publication.

Congratulations, Rui and Kun, for respectively leading these two remarkable studies!

Facile chlorination of graphene

Electrochemical functionalization of graphene in the aqueous phase: See how we moved from a pseudohalogen to real halogens, including the table salt! [Link]

Congratulations, Wan and Yunqi!

A multidimensional single-molecule & super-resolution approach for membrane diffusion

By integrating SMdM (single-molecule displacement/diffusivity mapping) with spectrally resolved SMLM and 3D-SMLM, we resolve and differentiate between nanoscale diffusional heterogeneities in live-cell membranes. See also our new principal-direction SMdM (pSMdM) analysis! [Link]

Congratulations, Rui and Kun!

Graphene-enabled, spatially controlled electroporation of adherent cells for live-cell super-resolution microscopy

Another remarkable integration of graphene and super-resolution microscopy –with unique spatiotemporal controls, too! [Link]

Congratulations, Seonah, Wan, and Meg!

Single-molecule displacement mapping unveils nanoscale heterogeneities and charge effects in intracellular diffusivity

We extend super-resolution microscopy to the new dimensions of single-molecule velocity and diffusivity. We thus unveil rich, nanoscale heterogeneities and charge effects in intracellular diffusion. Intriguingly, we find the possession of positive, but not negative, net charges drastically impedes diffusion –why? Read our paper to find out! [Link]

Congratulations, Limin, Kun, Rui, and Wan! Another milestone!