Adhesive processes in aqueous media play a crucial role in nature and are important for many technological processes. However, direct quantification of adhesion still requires expensive instrumentation while their sample throughput is rather small. Here we present a fast, and easily applicable method on quantifying adhesion energy in water based on interferometric measurement of polymer microgel contact areas with functionalized glass slides and evaluation via the Johnson–Kendall–Roberts (JKR) model. The advantage of the method is that the microgel matrix can be easily adapted to reconstruct various biological or technological adhesion processes. Here we study the suitability of the new adhesion method with two relevant examples: (1) antibody detection and (2) soil release polymers. The measurement of adhesion energy provides direct insights on the presence of antibodies showing that the method can be generally used for biomolecule detection. As a relevant example of adhesion in technology, the antiadhesive properties of soil release polymers used in today’s laundry products are investigated. Here the measurement of adhesion energy provides direct insights into the relation between polymer composition and soil release activity. Overall, the work shows that polymer hydrogel particles can be used as versatile adhesion sensors to investigate a broad range of adhesion processes in aqueous media.

The performance of artificial nerve guidance conduits (NGC) in peripheral nerve regeneration can be improved by providing structures with multiple small channels instead of a single wide lumen. 3D-printing is a strategy to access such multi-channeled structures in a defined and reproducible way. This study explores extrusion-based 3D-printing of two-component hydrogels from a single cartridge printhead into multi-channeled structures under aseptic conditions. The gels are based on a platform of synthetic, anhydride-containing oligomers for cross-linking of gelatinous peptides. Stable constructs with continuous small channels and a variety of footprints and sizes were successfully generated from formulations containing either an organic or inorganic gelation base. The adjustability of the system was investigated by varying the cross-linking oligomer and substituting the gelation bases controlling the cross-linking kinetics. Formulations with organic N-methyl-piperidin-3-ol and inorganic K2HPO4 yielded hydrogels with comparable properties after manual processing and extrusion-based 3D-printing. The slower reaction kinetics of formulations with K2HPO4 can be beneficial for extending the time frame for printing. The two-component hydrogels displayed both slow hydrolytic and activity-dependent enzymatic degradability. Together with satisfying in vitro cell proliferation data, these results indicate the suitability of our cross-linked hydrogels as multi-channeled NGC for enhanced peripheral nerve regeneration.

Cardiovascular disease (CVD) is ranked the second leading cause of death in Canada, with 53,704 heart disease-related deaths documented in 2020 alone. After a patient sustains cardiac injury, such as a myocardial infarction (MI), the heart is often unable to undergo sufficient self-recovery for healthy cardiac regeneration and repair; this is largely attributed to fibrotic tissue development at the injury site and subsequent pathological ventricular remodeling. The prevalence of MI events has created a considerable demand to develop novel strategies for effective and safe post-MI therapies. Research has indicated that post-MI modifications interfere with endogenous cardiac repair mechanisms, resulting in a pathological state. After an infarction, there is an accumulation of methylglyoxal (MG) at the site of injury. It has been suggested that MG contributes to ventricular fibrotic development, however its underlying mechanism remains unclear. Additionally, the effects that the post-MI cardiac environment, specifically MG accumulation, has on post-MI therapies and biomaterials has not been sufficiently established. Accordingly, the primary focus of this research project is to elucidate the effects of MG on the collagen-rich extracellular matrix (ECM) of the heart and key cardiac cells involved in the repair process. Further, the interaction between MG and a promising collagen-based hydrogel therapy is investigated, exploring the effects of MG on the hydrogel’s degradative process. It was found that the MG modification of hydrogels did not alter the degradation rate. Additionally, the degradation products of hydrogels, and MG-modified substrates did not affect the properties and formation of myofibroblasts.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Under senaste decennierna, har intresset kring implantat från naturliga och syntetiska polymerer ökat markant i samband med en ökad marknadsefterfrågan på vävnadsdonationer. Detta har lett till efterforskningen av nya in-situ formerande geler med formbevarande egenskaper in-vivo. Extracellulära matrisen (ECM) innehåller flertal makromolekylära komponenter med stödjande och nätverksformerande egenskaper, då de ofta är essentiella strukturella konstituenter i biologiska system. Den huvudsakliga beståndsdelen i ECM-nätverket, kollagen typ-1, har undersökts som en kandidat för utvecklingen av nya modifierade biomaterial med cellförökande-, biokompatibla-, icke-svällande samt injicerbara egenskaper. I detta projekt var grisderiverat kollagen modifierat med furfuryl glycidyl eter, och tvärbundet med 10 kDa 8-armad PEG-malimid, vilket genomgick kovalenta Diels-alder klick-reaktioner. Fyra formuleringar användes i experimenten, baserat på de stökiometriska förhållandet mellan furan och malimid i det kemiskt modifierade kollagenet. Dessa kollagen-baserade hydrogeler undersöktes baserat på 4 wt% löst kollagen, med avseende på reologiska-, mekaniska-, bionedbrytbara och svällningsegenskaper.  Resultaten indikerar att en ökning i fastfas-mängd ledde till en förhöjning i hydrogelens styvhet. Detta kunde observeras genom en ökad lagringsmodul (G’) under reologiska mätningar. Samtidigt indikerade mätningarna att sprödheten av hydrogelen ökade i korrelation med ökningen av styvheten.  Vidare drogs slutsatsen att kovalenta interaktionerna är enbart delvis ansvarig för ökningen av G’. Jämförelser med tan delta och kritiska töjningen visade att det fanns fysiska interaktioner mellan polymererna vilket också bidrog till ökningen av G’ för gelformuleringar som innehöll furan-till-malimid förhållanden på 1:1 och 1:4. Dessa fysiska interaktioner tros härstamma från en ökning av hydrofobiska effekter mellan kollagen kedjorna, då agglomerering och löslighetssvårigheter i vattenlösningar observerades i flertal experiment. Kollagen-PEG-Malimid hydrogelen var också injicerbar genom 15G kanyler, nedbrytbar in-vitro i närvaro av kollagenas, och uppvisade låg svällning i vatten. Inga cellexperiment genomfördes, och därav kunde inga slutsatser dras i hydrogelens cellförökande egenskaper. Däremot har tidigare arbete av Dr Jamadi visat att kollagen-PEG-malimid hydrogel med 2 vikt% haft kapacitet att inkapsla celler. Detta kan vara en indikation att högre viktprocent av gelen också kan uppvisa samma effekt vid framtida försök.Sammanfattningsvis, kunde slutsatsen dras att hydrogelen uppvisar flertal av de spekulerade, samt några av de eftertraktade egenskaperna hos en injicerbar hydrogel som potentiellt kan användas kliniskt. / In recent decades, the interest in implants manufactured from natural and synthetic polymers has grown as the demand for tissue donations has increased. This process has led to the pursuit of new, in-situ forming gels with shape-retaining properties in-vivo. The extracellular matrix (ECM) contains several macromolecular constituents with scaffold forming capabilities and is an inherent part of the body. The main component in the ECM-scaffold, collagen type-I, has been investigated as a candidate for novel modified biomaterials with cell proliferating, biocompatible, non-swelling, and injectable properties. Collagen was modified with furfuryl glycidyl ether and crosslinked with 10 kDa 8-arm PEG-maleimide, which undergoes Diels-alder covalent click-type reactions. Four formulations were used, based on a stoichiometric ratio of furan to maleimide (1:1-1:4). These materials' properties were evaluated at 4 wt% collagen for rheological-, mechanical-, biodegradability and swelling characteristics. The results indicated that an increase in solid content improved stiffness in the hydrogel.  This was observed by an increase of storage modulus (G’) during rheological measurements. The same measurements also indicated that the hydrogel showed an increase in brittle characteristics correlated with higher solid content.  Furthermore, it was concluded that the covalent interactions are partly responsible for the increase of G’. Comparisons in tan delta and critical strain showed that there are physical interactions that cause the increase in moduli for gel formulations containing furan to maleimide ratios of 1:1 and 1:4. These physical interactions are thought to stem from the increase in hydrophobic effects of the modified collagen, as agglomeration and solubility issues in aqueous solutions are observed in multiple experiments.  Collagen-PEG-maleimide hydrogel was also injectable through a 15-gauge needle, degradable in-vitro, and showed low swelling. No cell experiments were performed, and hence no conclusions could be made of this aspect of the hydrogel. However, work has been performed by Dr Jamadi, which indicates that the Collagen-PEG-Maleimide hydrogel with lower weight percentages allows for cell encapsulation. Hence, it could be concluded that several characteristics of tissue mimetic material were met with this hydrogel.