Development of an alignment method for small histological samples
Koivusalo, Laura (2015)
Koivusalo, Laura
2015
Master's Degree Programme in Materials Science
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2015-06-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201505181289
https://urn.fi/URN:NBN:fi:tty-201505181289
Tiivistelmä
Small histological samples, such as prostate biopsies, make up a significant part of histology laboratories’ workload due to their demanding handling and large quantities. During tissue sample handling, the small needle biopsies are embedded in paraffin and sectioned onto microscope slides for pathological evaluation. New methods are needed to improve the handling of thin biopsy cores to optimize the quality of patient diagnosis and cost-efficiency of histological sample preparation.
The aim of this thesis was to develop an alignment method for reducing the amount of manual handling steps in tissue processing and ensuring high quality tissue samples for faster and more accurate diagnosis. For this purpose, a device was designed to hold multiple samples simultaneously and in the same plane for maximal tissue representation on single microscope slide. The device was designed so that it can be removed from the paraffin block to allow for easy sectioning of the tissue samples, without affecting the pathological evaluation.
Two different kinds of prototypes were manufactured for an alignment device: dopa-mine coated silicone elastomer pads and gelatin-siloxane hydrogel pads. Dopamine is the functional molecule of mussel foot proteins responsible for their attachment to virtually any surface, which is why it was selected for coating material for the inert silicone pads. Gelatin-siloxane hydrogel was selected because it was thought to provide both attachment and supportive functions simultaneously.
We evaluated the performance of the prototypes in the histological sample handling process by testing their capability to attach tissue samples from the biopsy needle and keep them in place during sample processing and embedding. Dopamine coated silicone pads were not successful in keeping the tissue samples aligned. Device prototypes made from flexible and tough gelatin-siloxane hydrogel were successful in attaching the small tissue samples onto their surface using capillary force and wet adhesion. The hydrogel pads succeeded in immobilizing the samples during tissue processing and were remova-ble from the resulting paraffin blocks, as designed. However, the hydrogel pads distorted in the tissue processor, limiting their use in small tissue sample alignment. Further development is still needed to find a suitably stiff material or structure to keep the device from bending during tissue processing. Furthermore, the ease of sample attachment should be improved even further to make the alignment device more attractive for use in clinical practice.
The aim of this thesis was to develop an alignment method for reducing the amount of manual handling steps in tissue processing and ensuring high quality tissue samples for faster and more accurate diagnosis. For this purpose, a device was designed to hold multiple samples simultaneously and in the same plane for maximal tissue representation on single microscope slide. The device was designed so that it can be removed from the paraffin block to allow for easy sectioning of the tissue samples, without affecting the pathological evaluation.
Two different kinds of prototypes were manufactured for an alignment device: dopa-mine coated silicone elastomer pads and gelatin-siloxane hydrogel pads. Dopamine is the functional molecule of mussel foot proteins responsible for their attachment to virtually any surface, which is why it was selected for coating material for the inert silicone pads. Gelatin-siloxane hydrogel was selected because it was thought to provide both attachment and supportive functions simultaneously.
We evaluated the performance of the prototypes in the histological sample handling process by testing their capability to attach tissue samples from the biopsy needle and keep them in place during sample processing and embedding. Dopamine coated silicone pads were not successful in keeping the tissue samples aligned. Device prototypes made from flexible and tough gelatin-siloxane hydrogel were successful in attaching the small tissue samples onto their surface using capillary force and wet adhesion. The hydrogel pads succeeded in immobilizing the samples during tissue processing and were remova-ble from the resulting paraffin blocks, as designed. However, the hydrogel pads distorted in the tissue processor, limiting their use in small tissue sample alignment. Further development is still needed to find a suitably stiff material or structure to keep the device from bending during tissue processing. Furthermore, the ease of sample attachment should be improved even further to make the alignment device more attractive for use in clinical practice.