Why is it possible to measure living cells with MP-SPR?

Kinetics of living cell and bacteria attachment in real-time

Thanks to unique SPR angular scanning configuration, MP-SPR is able to measure even micron thick samples, including cells and bacteria. Some of the cell types that have been measured in MP-SPR instruments include cell lines, stem cells as well as bacteria (among others HeLa, MDCKII, A549, LNCaP, ARPE19, PC-3, HepG2, MCF7, BK or E. coli).

Prove internalization label-free

Upon drug uptake, the cell signaling cascade typically makes the cell to undergo dynamic mass redistribution (DMR) which can be clearly seen in the MP-SPR multiparametric plots. On the other hand, permeation can be seen as binding of drugs to the substrate. Thanks to the angular scan mode in MP-SPR, it is possible to capture all of this information and to provide high-content data about living cell interaction with drugs or nanoparticles. So far, other label-free instruments were only able to show cell spreading or interaction in nanoparticles in static assays. We push the boundaries further and show internalization in flow conditions. This brings the assay even closer to in vivo conditions and provides a better model for translation of results to clinical field. Until now, different types of cells were measured interacting with small molecular drugs, DNA polyplexes, liposomes, silica nanoparticles, gold nanoparticles, viruses and exosomes. 

This pioneering work has so far been focused on drug delivery. However, similar approach can be applied also to future nanotoxicity in vitro assays.

Surface freedom

In tissue engineering as well as in in vitro assays, it is essential to ensure good adhesion of cells to the surface. Different cell types prefer different surfaces. Therefore, it is essential that the users are not defined by the surfaces provided by us, but that they can modify the surfaces with their own methods and coatings.

Since our MP-SPR instruments use advanced elastomeric coating on the prism, we can use simple coated glass slides as measurement substrates. This allows the substrates to be modified ex-situ. Extended scanning angular range also allows for variety of substrate coatings. 

For cell growth, most typical substrates are Au, SiO2 ("glass-like material"), calcium phosphate (CaP, "bone-like material"), polystyrene surfaces ("well-plate -like material"). These are later modified depending on the cell type with laminin, fibronectin or other growth-promoting proteins.

Users can use a variety of techniques for surface modifications of the sensor surfaces, including dip coating, spray coating, Langmuir-Blodgett, Langmuir-Schaefer, layer-by-layer, ALD, CVD and many others. The cell can be incubated prior to the experiment in a standard incubator and after that inserted into MP-SPR instrument for interaction measurements.

Our gold sensors can be re-used even after work with living cells thanks to a special adhesion layer which withstands even acid treatments and sterilization. Typical cleaning protocols are provided to our users in our user intranet.

Environmental control

The instrument allows temperature control in the measurement area between 15 to 45 degrees Celsius. Also the shear-stress can be controlled by changing the flow-rate through the measurement channel. The measurements can be performed both in static and dynamic flow conditions.

Combination of MP-SPR with electrochemistry

It is possible to combine MP-SPR with electrical stimulation of the living cells or with recording of the electrical potential changes across the cell population. The MP-SPR instruments can be used with a number of different flow-cells, including electro-chemical flow-cell. We provide three different electrode types for different measurement needs.


 

Recommended MP-SPR instruments for measurements of living cells:

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