Investigation of switchable polymer coatings on ceramic membranes for alternative forensic sampling.
* Please note: This is an internship position based at the University of Twente
Evidence Pen-Investigation of active matter for enhanced forensic sample collection
As part of the investigation of various methods for collecting forensic samples, the “Criminal Investigation” project includes a subcategory focused on technological collection devices. Specifically, this project work explores the use of cotton swabs and potential alternatives, such as ceramic membranes or various polymers with switchable properties. This student work will specifically focus on the implementation of switchable polymers for controlled cell release from porous ceramic membranes.
The aim is to test a prototype device (Evidence-Pen) exploiting said functionality. The most popular thermo-responsive polymer is PNIPAM [Poly(N-isopropylacrylamide)], which is already used in culture dishes. By lowering the temperature from 37 -25°C, the chains dehydrate, switching from hydrophilic to hydrophobic and cellular adhesion is no longer possible.
A layout of the prototype is presented in Figure 1 and 2. The PNIPAM is deposited onto an inorganic ceramic membrane (α-Alumina; Pervatech) disc. Said disc is itself attached to a 3D-printed pen-like housing. The housing is further equipped with a PDMS-Bumper to prevent direct contact and scratching of surfaces with the ceramic membrane. In the centre of Nozzle, a metallic rod is in contact with the membrane and a heater element at the other end. The heater thus conducts the heat through the rod and the membrane towards the polymer coating. This enables the switching mechanism, additionally to flushing the membrane from the backside with a buffer solution.
The student should construct a device based on the description and requirements and further characterize it via the following techniques:
- Contact angle measurements
- Fluorescent microparticle testing
- Fluorescent microscopy of white blood cell adhesion and morphology on ceramic membranes
- SEM analysis of polymeric coating on the microporous membrane
- Quantitative analysis of collection efficiency via fluorescent cell counting pre and post-sampling
This project combines targeted design and literature research on switchable polymers with the first prototyping into a device. The extend of characterisation can be decided on based on the progress of the assignment.
Project duration:
Max 6 months
Educational programs:
– Biology and Medical Lab (BML)
– Chemistry (CH),
– Chemical Technology (CT),
Applied Nanotechnology
Interested, please send your motivation letter and CV before May 2025 to Michel Nunnenkamp (m.nunnenkamp-1@utwente.nl)