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NEWS

March 2026 ESRFnews

Researchers at the ESRF have

demonstrated a new X - ray imaging

approach that allows highly strained

nanocrystals to be analysed in three

dimensions , overcoming a major

limitation of existing techniques . Known

as Bragg coherent modulation imaging

( BCMI ) , the method was developed and

experimentally realised at the highly

coherent ID01 beamline .

Bragg coherent diffraction imaging

( BCDI ) is widely used to image

nanoscale strain and defects inside

single crystals in a non - destructive

way , but it only works reliably when

strain levels are relatively small . When

deformation becomes large and

complex , standard phase - retrieval

algorithms often fail , producing

artefacts or ambiguous results .

The new BCMI approach addresses

this problem by introducing a

wavefront modulator into the

diffracted beam , providing a strong

and well - defined constraint for the

reconstruction . In experiments ,

the ESRF ’ s Jiangtao Zhao and

colleagues demonstrated that – unlike

conventional BCDI – the use of BCMI

could recover the internal structure of

highly strained platinum nanocrystals .

Success relied on the development

of a dedicated nano - goniometer

and ptychography to calibrate the

modulator , as well as new position -

correction algorithms .

The results showed that BCMI

delivers greater robustness , higher

spatial resolution and unambiguous

reconstructions compared with

BCDI even for crystals with strong

strain inhomogeneities Phys Rev

Lett 135 256101 The main current

limitation is that the close proximity

required between the modulator and

sample restricts the available sample

environment

By extending coherent X ray

imaging to more realistic and highly

strained materials BCMI opens

new possibilities for studying strain

and defect evolution in functional

nanomaterials the researchers say

New method images highly

strained nanocrystals

Scientists led by the Institut de

Biologie Structurale ( IBS ) have

combined advanced X - ray techniques

to reveal how a vitamin B12 -

dependent photoreceptor converts

light into a biological response .

Drawing on key ESRF experiments ,

the results show in detail how

tiny photo - induced changes are

amplified into large - scale structural

rearrangements .

The photoreceptor , known as

CarH , regulates the production of

carotenoids – pigments that protect

bacteria from harmful light . In

the dark , CarH binds to DNA and

suppresses gene expression ; when

exposed to light however it releases

the DNA allowing carotenoids

to be produced and protecting the

cell against photo damage While

previous structures had revealed the

dark and light activated end states

the molecular pathway connecting

them had remained elusive

To find it the IBS led team

combined time resolved serial

femtosecond crystallography at X ray

free electron lasers with time resolved

X ray solution scattering at the ESRF

allowing CarH s structural dynamics

to be followed under physiological

conditions . At the ESRF ’ s ID09

beamline , the experiments captured

large - scale rearrangements of the

protein , including the dissociation

of the CarH tetramer that ultimately

enables gene activation .

“ At ID09 , we could see for the first

time the structural changes at the

protein level and the dissociation of

the CarH tetramer into monomers , ”

says Giorgio Schirò , one of the study

leaders .

The ESRF measurements provided

a crucial bridge between ultrafast

techniques – which capture the

earliest photochemical events around

the vitamin B12 chromophore

and the slower biologically

relevant conformational changes

Additional experiments at the ESRF s

BM07 FIP2 beamline helped

clarify the chemical nature of a key

intermediate further strengthening

the mechanistic picture Nature doi

10 1038 s41586 025 10074 2 The

ESRF allowed us to connect the dots

explains coauthor Martin Weik at

the IBS We could see how the initial

light reaction is converted into a

biologically meaningful response

C E A A N D M A R I A D A V I L A M I L I A N I

X - rays capture vitamin B12 sensing light

P R L

“ At ID09 , we

could see for

the first time

the structural

changes at the

protein level ”