Technology offer: Drug Screening with soft hydrogel particles

Scientists from the Max Planck Institute of Colloids and Interfaces have developed a simple and robust label-free screening technique using soft colloidal probes (SCP) as sensors. The invention is based on measuring the deformation of the SCPs while being in contact with specific substances and can be used in the fields of medical diagnostics and drug screening.
Hydrogels
Picture: A ligand functionalized probe binds to the receptor on the substrate surface. It is deformed depending on the analyte concentration and affinity, which can be determined by the RICM images. The dark area in the center corresponds to the contact area.

The demand for robust and cost-effective analysis in the fields of medical diagnostics and drug screening has risen in recent years. Also in related fields like veterinary diagnostics, biotechnology, agricultural sciences, and toxin detection cost effective and fast analytic methods are required. Today’s research focuses on label-free sensing techniques because they operate without modification of analyte molecules (e.g. by fluorescent labeling) and thus show high selectivity. However existing label-free techniques are expensive, involve considerable experimental effort and are therefore limited to research settings.

Scientists from the Max Planck Institute of Colloids and Interfaces have developed a simple and robust label-free screening technique using ligand/receptor functionalized soft colloidal probes (SCP) as sensors. The technique is based on the idea that functionalized SCPs (e.g. based on polyethylenglycol – PEG – hydrogels) are mechanically deformed upon adhesion on a surface modified with a specific binding partner. This deformation is altered by a competing analyte: Depending on the concentration and affinity of the analyte, the contact area between SCP and surface changes.

Thus, by measuring the contact area changes the affinity or concentration of added analyte can be determined. Technically this can be done via reflection interference contrast microscopy (RICM), whereupon a change of the contact area results in different brightness reflection contrast images.

The principle can be adapted for the purpose of high-throughput screening: It can be shown that the average change of contact area for an array of SCPs upon the analyte addition causes a change in the overall brightness of the according reflection contrast image. Therefore, this change in brightness can be measured photometrically and used to determine the analyte affinity or concentration without image processing steps on individual contact surfaces. This allows for higher throughput and automation of the screening process resulting in lower costs and better manageability.

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