# Microfluidic chips for biomolecular crystal growth and serial crystallography

P Pachl, Léna Coudray, Philippe Bénas, C Sauter

► To cite this version:

P Pachl, Léna Coudray, Philippe Bénas, C Sauter. Microfluidic chips for biomolecular crystal growth and serial crystallography. XXVI IUCr Congress Melbourne, Australia, 22-29 August 2023, Aug 2023, Melbourne (AUS), Australia. Acta Crystallographica Section A, 79, pp.C1348, 2023, 10.1107/S2053273323082736. [https://doi.org/10.1107/S2053273323082736](https://doi.org/10.1107/S2053273323082736). [CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)

HAL Id: hal-04792108

https://hal.science/hal-04792108v1

Submitted on 21 Nov 2024

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# Microfluidic chips for biomolecular crystal growth and serial crystallography

Petr Pachl, Léna Coudray, Philippe Bénas & Claude Sauter

Architecture et Réactivité de l'ARN – IBMC – CNRS – Université de Strasbourg

p.pachl@ibmc-cnrs.unistra.fr / c.sauter@ibmc-cnrs.unistra.fr

## Overview

For about fifteen years, microfluidics has opened up new possibilities and brought many benefits for the crystallization of biomolecules. Indeed, microfluidic systems facilitate the manipulation of nanovolumes of sample solutions, as well as extreme miniaturization and parallelization of crystallization assays. In addition, they provide a convection-free environment that favors the growth of high-quality crystals [1].

We present a new multifunctional microchip design [2] combining: 1) search and optimization of crystallization conditions of biomolecules by the counter-diffusion method, 2) crystal identification by fluorescence microscopy, 3) microcrystalline seeding, 4) derivatization of crystals by substrate soaking, and 5) *in situ* crystal analysis at room temperature. This design was tested on a large panel of biomolecules including soluble or membrane proteins. Several structures were solved by serial crystallography under synchrotron radiation.

## ChipX design

<figure><img src="image_2.png" /><figcaption>Biomolecule solution inlet</figcaption></figure>

Crystallant reservoirs

<figure><img src="image_3.png" /><figcaption>## In situ crystal analysis</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>## Crystal detection by fluorescence</figcaption></figure>

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /><figcaption>Standard setup
SLS – PXIII beamline</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>On-chip diffraction
at room-temperature</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>SBS chip holders</figcaption></figure>

<figure><img src="image_11.png" /><figcaption>## RT structure determination</figcaption></figure>

A) Camelid nanobody

B) Protease I
*Pyrococcus horikoshii*

C) CCA-adding enzyme + CTP
*Planococcus halocryophylus*

D) Synthetic RNA duplex

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

## In brief

A chip design dedicated to advanced crystallogenesis strategies:

* ✓ Crystallization by counter-diffusion

* ✓ Easy crystal visualization by fluo-labelling

* ✓ Easy crystal seeding and soaking

* ✓ Fast serial analysis at room-temperature

User-friendly, no extra equipment needed!

<figure><img src="image_14.png" /></figure>

SCAN ME

## References

[1] Sauter C., Dhouib K., Lorber B. From macrofluidics to microfluidics in the crystallization of biological macromolecules. *Cryst. Growth Des.*, **2007**, 7, 2247-50.

[2] de Wijn R., Hennig O., Roche J., Engilberge S., Rollet K., Fernandez-Millan P., Brillet K., Betat H., Mörl M., Roussel A., Girard E., Mueller-Dieckmann C., Fox G.C., Olieric V., Gavira JA., Lorber B., Sauter C. A simple and versatile microfluidic device for efficient biomacro-molecule crystallization and structural analysis by serial crystallography, *IUCrJ*, **2019**, 6(3); 454-464.