Fraunhofer speeds up virus analysis using laser-induced transport

30 Nov 2022

B-Cell-Immune project could allow faster response to new viruses and pandemics.

A consortium including research center Fraunhofer ILT and vendors LPKF Laser & Electronics is developing a high-throughput method for assessing individual immune responses to Covid-19.

The project, named B-Cell-Immune, has been federally funded under a German program aimed at the prevention and treatment of epidemic infections with innovative medical technologies.

Memory B cells are a type of lymphocyte in the immune system known to be capable of indicating the previous infections or vaccinations to which the system has been exposed. A rapid and cost effective method for determining this status across populations would be significant in tracking Covid-19 and potentially other viruses and pandemics.

The project makes use of the Arralyze platform developed by LPKF, a glass array technology using laser induced deep etching (LIDE) to produce high aspect ratio channels and wells in glass substrates, wells that can then be filled with cells or other samples.

Fraunhofer ILT and LPKF will also employ a laser induced forward transfer (LIFT) process for transporting the cells through the platform's analytical stages. LIFT is a precise and contact-free process to fill the microscopically small wells and to remove cells from them without the need for pipettes, allowing the analytical process to work on small sample volumes for diagnostics.

Identify infections and new variants

LIFT was first developed as a direct writing technique for inorganic and organic materials, an additive manufacturing approach in which the action of a laser printed a small amount of material from a donor layer onto a receiving substrate. With the right laser parameters, the deposition process can be gentle enough to keep all the functionality of the printed materials, opening up the possibility of using LIFT for printing delicate biomolecules and cells as well.

In 2015 Bordeaux-based bioprinting developers Poietis used similar principles to design a system for printing cells onto a substrate, using a short laser pulse to create a cavitation bubble within a liquid reservoir. The bubble's expansion forcibly ejects a jet of that liquid, allowing a drop of it to fall onto a substrate.

Fraunhofer ILT has been developing an implementation of the same technique termed LIFToscope, an automated AI-assisted module for non-contact isolation of cells from large cell cultures. In this version, a pulse from a 3-micron laser source applied to a hydrogel layer creates a vapor bubble, with the expansion and collapse of the bubble propelling the transfer layer forward and moving an embedded cell onto a receiver slide.

For B-Cell-Immune, the intention is that a LIFT technique will allow samples of SARS-CoV-2 virus-specific memory B cells to be rapidly transferred through the stages of a PCR-based detection regime, speeding up the process of identifying infections and potentially becoming an important part of responses to new viruses or variants.

"This method takes antibody-based therapy and diagnostics to a completely new level," commented Christina Bade-Döding from project partner Hannover Medical School.