Papers by Torbjörn Pettersson
Multifunctional cancer-targeting strategy for encapsulating doxorubicin by folate-onjugated and q... more Multifunctional cancer-targeting strategy for encapsulating doxorubicin by folate-onjugated and quercetin-anchored pluronic mixed micelle systems
Multifunctional cancer-targeting strategy for encapsulating doxorubicin by folate-onjugated and q... more Multifunctional cancer-targeting strategy for encapsulating doxorubicin by folate-onjugated and quercetin-anchored pluronic mixed micelle systems
Effective isolation and purification of circulating tumor cells from whole blood provides importa... more Effective isolation and purification of circulating tumor cells from whole blood provides important capability for clinical application and biological research. Here, we demonstrate a single step s ...
A bio-functionalized microsystem was developed for the capture and release of cancer cells from w... more A bio-functionalized microsystem was developed for the capture and release of cancer cells from whole blood. Effective isolation and purification of circulating tumor cells from whole blood provide ...
Nordic Pulp & Paper Research Journal, 2021
Large deformations under in-plane compression of paperboard appear in forming processes like hydr... more Large deformations under in-plane compression of paperboard appear in forming processes like hydroforming, pressforming and deep drawing, but the mechanisms of deformation have not been studied on a micromechanical level. A constrained in-plane compression test is presented. This test allows for in-plane compression, buckling, wrinkling and compaction. The constrained compression test is realized using a DEBEN CT-500 in-situ tester for laboratory microtomography and synchrotron microtomography. Experiments with five different materials spanning from laboratory handsheets to commercially available multi-layered paperboards are performed. Image processing is used to observe the local out-of-plane fiber orientation and compaction. A phenomenological investigation of the deformation behavior of these materials is presented. Delamination is found to be the primary mechanisms of failure in the multi-layered boards. Furthermore, a porous network structure, created by using long and minimal...
The macro-and microstructural evolution of water swollen and ethanol swollen regenerated cellulos... more The macro-and microstructural evolution of water swollen and ethanol swollen regenerated cellulose gel beads have been determined during drying by optical microscopy combined with analytical balance measurements, small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS). Two characteristic length scales, which are related to the molecular dimension of cellulose monomer and elongated aggregates of these monomers, could be identified for both types of beads by SAXS. For ethanol swollen beads, only small changes to the structures were detected in both the SAXS and WAXS measurements during the entire drying process. However, the drying of cellulose from water follows a more complex process when compared to drying from ethanol. As water swollen beads dried, they went through a structural transition where elongated structures changed to spherical structures and their dimensions increased from 3.6 to 13.5 nm. After complete drying from water, the nanostructures were characterized as a combination of rodlike structures with an approximate size of cellulose monomers (0.5 nm), and spherical aggregates (13.5 nm) without any indication of heterogeneous meso-or microporosity. In addition, WAXS shows that cellulose II hydrate structure appears and transforms to cellulose II during water evaporation, however it is not possible to determine the degree of crystallinity of the beads from the present measurements. This work sheds lights on the structural changes that occur within regenerated cellulose materials during drying and can aid in the design and application of cellulosic materials as fibers, adhesives, and membranes.
Analytical Methods, 2018
The mechanical properties of different pulp fibres in liquid were measured using an atomic force ... more The mechanical properties of different pulp fibres in liquid were measured using an atomic force microscope.
Cellulose, 2019
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RSC Adv., 2017
A novel POC sample preparation technology, “Slipdisc”, based rotational slipchip technology is pr... more A novel POC sample preparation technology, “Slipdisc”, based rotational slipchip technology is presented. In operation, the hand-winded slipdisc platform uses a unique clockwork mechanism to manipulate minute amount of liquids.
Anal. Methods, 2017
The mechanical properties of wet cellulose are investigated using an atomic force microscope AFM ... more The mechanical properties of wet cellulose are investigated using an atomic force microscope AFM and calculated using a linearized DMT model.
Cellulose, 2017
Flexibility and modulus of elasticity data for two types of wet cellulose fibres using a direct f... more Flexibility and modulus of elasticity data for two types of wet cellulose fibres using a direct force-displacement method by means of AFM are reported for never dried wet fibres immersed in water. The flexibilities for the bleached softwood kraft pulp (BSW) fibres are in the range of 4-38 9 10 12 N-1 m-2 while the flexibilities for the thermomechanical pulp (TMP) fibres are about one order of magnitude lower. For BSW the modulus of elasticity ranges from 1 to 12 MPa and for TMP between 15-190 MPa. These data are lower than most other available pulp fibre data and comparable to a soft rubber band. Reasons for the difference can be that our measurements with a direct method were performed using never dried fibres immersed in water while other groups have employed indirect methods using pulp with different treatments.
Nano Letters, 2017
This work aims at understanding the excellent ability of nanocelluloses to disperse carbon nanoma... more This work aims at understanding the excellent ability of nanocelluloses to disperse carbon nanomaterials (CNs) in aqueous media to form long-term stable colloidal dispersions without the need for chemical functionalization of the CNs or the use of surfactant. These dispersions are useful for composites with high CN content when seeking waterbased, efficient, and green pathways for their preparation. To establish a comprehensive understanding of such dispersion mechanism, colloidal characterization of the dispersions has been combined with surface adhesion measurements using colloidal probe atomic force microscopy (AFM) in aqueous media. AFM results based on model surfaces of graphene and nanocellulose further suggest that there is an association between the nanocellulose and the CN. This association is caused by fluctuations of the counterions on the surface of the nanocellulose inducing dipoles in the sp 2 carbon lattice surface of the CNs. Furthermore, the charges on the nanocellulose will induce an electrostatic stabilization of the nanocellulose−CN complexes that prevents aggregation. On the basis of this understanding, nanocelluloses with high surface charge density were used to disperse and stabilize carbon nanotubes (CNTs) and reduced graphene oxide particles in water, so that further increases in the dispersion limit of CNTs could be obtained. The dispersion limit reached the value of 75 wt % CNTs and resulted in high electrical conductivity (515 S/cm) and high modulus (14 GPa) of the CNT composite nanopapers.
Nanoscale, 2016
In this study the wet adhesion between Layer-by-Layer (LbL) assembled films of triblock copolymer... more In this study the wet adhesion between Layer-by-Layer (LbL) assembled films of triblock copolymer micelles was investigated. Through the LbL assembly of triblock copolymer micelles with hydrophobic, low glass transition temperature (T g) middle blocks and ionic outer blocks, a network of energy dissipating polymer chains with electrostatic interactions serving as crosslinks can be built. Four triblock copolymers were synthesized through Atom Transfer Radical Polymerisation (ATRP). One pair had a poly(2-ethyl-hexyl methacrylate) middle block with cationic or anionic outer blocks. The other pair contained the same ionic outer blocks but poly(n-butyl methacrylate) as the middle block. The wet adhesion was evaluated with colloidal probe AFM. To our knowledge, wet adhesion of the magnitude measured in this study has not previously been measured on any polymer system with this technique. We are convinced that this type of block copolymer system grants the ability to control the geometry and adhesive strength in a number of nano-and macroscale applications. † Electronic supplementary information (ESI) available: Additional characterisation of the synthesised materials. See
Chem. Commun., 2014
Poly(ionic liquid)s were grafted onto cellulose nanofibrils (CNFs) to provide superior dispersibi... more Poly(ionic liquid)s were grafted onto cellulose nanofibrils (CNFs) to provide superior dispersibility to CNFs in water and various organic solvents.
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Papers by Torbjörn Pettersson