Browsing by Author "Yliperttula, Marjo"

Filter results by typing the first few letters
Now showing 1 - 11 of 11
  • AFM Force Spectroscopy Reveals the Role of Integrins and Their Activation in Cell-Biomaterial Interactions
    (2020-03-16) Harjumäki, Riina; Zhang, Xue; Nugroho, Robertus Wahyu N.; Farooq, Muhammad; Lou, Yan Ru; Yliperttula, Marjo; Valle-Delgado, Juan José; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Transmembrane protein integrins play a key role in cell adhesion. Cell-biomaterial interactions are affected by integrin expression and conformation, which are actively controlled by cells. Although integrin structure and function have been studied in detail, quantitative analyses of integrin-mediated cell-biomaterial interactions are still scarce. Here, we have used atomic force spectroscopy to study how integrin distribution and activation (via intracellular mechanisms in living cells or by divalent cations) affect the interaction of human pluripotent stem cells (WA07) and human hepatocarcinoma cells (HepG2) with promising biomaterials-human recombinant laminin-521 (LN-521) and cellulose nanofibrils (CNF). Cell adhesion to LN-521-coated probes was remarkably influenced by cell viability, divalent cations, and integrin density in WA07 colonies, indicating that specific bonds between LN-521 and activated integrins play a significant role in the interactions between LN-521 and HepG2 and WA07 cells. In contrast, the interactions between CNF and cells were nonspecific and not influenced by cell viability or the presence of divalent cations. These results shed light on the underlying mechanisms of cell adhesion, with direct impact on cell culture and tissue engineering applications.
  • Author Correction: Quantified forces between HepG2 hepatocarcinoma and WA07 pluripotent stem cells with natural biomaterials correlate with in vitro cell behavior (Scientific Reports, (2019), 9, 1, (7354), 10.1038/s41598-019-43669-7)
    (2020-12-01) Harjumäki, Riina; Nugroho, Robertus Wahyu N.; Zhang, Xue; Lou, Yan Ru; Yliperttula, Marjo; Valle-Delgado, Juan José; Österberg, Monika
     Comment/debate
    This Article contains two errors in the Discussion section under the subheading ‘Effect of material properties on the cell interactions’. “In accordance with previous findings measured with a different method and other cell types74, we observed that the un-normalized adhesion of a polysaccharide with cells was very weak, only about 2 nJ for WA07 and 2.7 nJ for HepG2 after 30 s in contact (Table S1e,f)” should read: “In accordance with previous findings measured with a different method and other cell types74, we observed that the un-normalized adhesion of a polysaccharide with cells was very weak, only about 1.6 fJ for WA07 and 2.7 fJ for HepG2 after 30 s in contact (Table S1e,f)”. Secondly, “The corresponding un-normalized adhesion values for LN-521 interactions were 3.8 nJ for WA07 and 33 nJ for HepG2 (Table S1e,f)” should read: “The corresponding un-normalized adhesion values for LN-521 interactions were 3.8 fJ for WA07 and 33 fJ for HepG2 (Table S1e,f)”. Additionally, the Supplementary Information that accompanies this Article contains errors in Table S1, S2 and S3. In Table S1, the units of adhesion energy are incorrectly given as nJ instead of fJ. Additionally, three values of adhesion energy for CNF in panels (b), (d) and (f) are incorrect. In Table S2, two values of radius are incorrect for CNF in panel (a) and Col I in panel (b). In Table S3, the units of adhesion energy are incorrectly given as nJ instead of fJ. The correct Tables S1, S2 and S3 appear below as Tables 1–3, respectively.
  • Fluorescence-suppressed time-resolved Raman spectroscopy of pharmaceuticals using complementary metal-oxide semiconductor (CMOS) single-photon avalanche diode (SPAD) detector
    (2016) Rojalin, Tatu; Kurki, Lauri; Laaksonen, Timo; Viitala, Tapani; Kostamovaara, Juha; Gordon, Keith C.; Galvis Rojas, Leonardo; Wachsmann-Hogiu, Sebastian; Strachan, Clare J.; Yliperttula, Marjo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In this work, we utilize a short-wavelength, 532-nm picosecond pulsed laser coupled with a time-gated complementary metal-oxide semiconductor (CMOS) single-photon avalanche diode (SPAD) detector to acquire Raman spectra of several drugs of interest. With this approach, we are able to reveal previously unseen Raman features and suppress the fluorescence background of these drugs. Compared to traditional Raman setups, the present time-resolved technique has two major improvements. First, it is possible to overcome the strong fluorescence background that usually interferes with the much weaker Raman spectra. Second, using the high photon energy excitation light source, we are able to generate a stronger Raman signal compared to traditional instruments. In addition, observations in the time domain can be performed, thus enabling new capabilities in the field of Raman and fluorescence spectroscopy. With this system, we demonstrate for the first time the possibility of recording fluorescence-suppressed Raman spectra of solid, amorphous and crystalline, and non-photoluminescent and photoluminescent drugs such as caffeine, ranitidine hydrochloride, and indomethacin (amorphous and crystalline forms). The raw data acquired by utilizing only the picosecond pulsed laser and a CMOS SPAD detector could be used for identifying the compounds directly without any data processing. Moreover, to validate the accuracy of this time-resolved technique, we present density functional theory (DFT) calculations for a widely used gastric acid inhibitor, ranitidine hydrochloride. The obtained time-resolved Raman peaks were identified based on the calculations and existing literature. Raman spectra using non-time-resolved setups with continuous-wave 785- and 532-nm excitation lasers were used as reference data. Overall, this demonstration of time-resolved Raman and fluorescence measurements with a CMOS SPAD detector shows promise in diverse areas, including fundamental chemical research, the pharmaceutical setting, process analytical technology (PAT), and the life sciences.
  • Light-activated and Gold Nanoparticle Mediated Drug Release from Liposomes
    (2007) Karvonen, Milla
     Helsinki University of Technology | Master's thesis
    Nanoteknologia lupaa tulevaisuudessa lääketutkimukselle paljon. Tässä työssä tutkitaan yhtä kontrolloitua lääkkeenvapautusta varten suunniteltua ja biologisesti yhteensopivaa nanosysteemiä. Lääkkeet kuljetetaan haluttuun kohteeseen kultananohiukkasia sisältävissä liposomeissa ja vapautetaan hallitusti optisella säteilytyksellä kultahiukkasten valoterminen vasteen avulla. Työn tarkoituksena on tutkia kultananohiukkasten valotermistä vastetta ja lämmön johtumista kultahiukkasesta liposomiin, sekä näihin vaikuttavia seikkoja. Lisäksi selvitetään lääkkeenvapautumisen mekanismeja kultaliposomeista. Näiden pohjalta pohditaan valolla indusoidun lääkkeenvapautuksen optimointia kliinisen käytön reunaehdot muistaen. Kultaliposomien termodynamiikkaa tarkastellaan kalorimetrialla ja kontrolloituun lääkkeenvapautukseen liittyviä entalpiamuutoksia ultraviolettikalorimetrialla. Liposomeja myös kuvataan läpäisyelektronimikroskoopilla kultahiukkasten jakautumisen selvittämiseksi. Työssä kuvataan lisäksi jatkotutkimuksissa käytettäväksi aiotut menetelmät. Liposomien valmistuksessa ilmenneiden ongelmien vuoksi työ on pääosin teoreettinen. Työssä saatiin kuitenkin selville mm. menetelmä kultananohiukkasten orgaanisen päällysteen paksuuden määrittämiselle. Orgaaninen päällyste vaikuttaa merkittävästi lämmön johtumiseen kultahiukkasesta ympäristöön, ja on siksi keskeinen parametri lääkkeenvapautuksen optimoinnissa. Tutkittu systeemi vaikuttaa lupaavalta, ja on aiemmin todistettu periaatteessa toimivaksi. Kuitenkin jatkossa on syytä etsiä toisaalta systeemin stabiiliuden ja toisaalta lääkkeen vapautuksen kannalta optimaalisinta kultananohiukkastyyppiä. Reunaehtoja ovat tehokas lääkkeenvapautus kohtuullisella lämpö- ja säteilyrasituksella kudoksille sekä lääkkeen pysyminen liposomin sisällä ilman säteilytystä.
  • Nanofibrillar cellulose hydrogel promotes three-dimensional liver cell culture
    (2012) Bhattacharya, Madhushree; Malinen, Melina M.; Lauren, Patrick; Lou, Yan-Rou; Kuisma, Saara W.; Kanninen, Liisa; Lille, Martina; Corlu, Anne; GuGuen-Guillouzo, Christiane; Ikkala, Olli; Laukkanen, Antti; Urtti, Arto; Yliperttula, Marjo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Over the recent years, various materials have been introduced as potential 3D cell culture scaffolds. These include protein extracts, peptide amphiphiles, and synthetic polymers. Hydrogel scaffolds without human or animal borne components or added bioactive components are preferred from the immunological point of view. Here we demonstrate that native nanofibrillar cellulose (NFC) hydrogels derived from the abundant plant sources provide the desired functionalities. We show 1) rheological properties that allow formation of a 3D scaffold in-situ after facile injection, 2) cellular biocompatibility without added growth factors, 3) cellular polarization, and 4) differentiation of human hepatic cell lines HepaRG and HepG2. At high shear stress, the aqueous NFC has small viscosity that supports injectability, whereas at low shear stress conditions the material is converted to an elastic gel. Due to the inherent biocompatibility without any additives, we conclude that NFC generates a feasible and sustained microenvironment for 3D cell culture for potential applications, such as drug and chemical testing, tissue engineering, and cell therapy.
  • Nanofibrillar cellulose-alginate hydrogel coated surgical sutures as cell-carrier systems
    (2017-08-01) Laurén, Patrick; Somersalo, Petter; Pitkänen, Irina; Lou, Yan Ru; Urtti, Arto; Partanen, Jouni; Seppälä, Jukka; Madetoja, Mari; Laaksonen, Timo; Mäkitie, Antti; Yliperttula, Marjo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Hydrogel nanomaterials, especially those that are of non-human and non-animal origins, have great potential in biomedical and pharmaceutical sciences due to their versatility and inherent soft-tissue like properties. With the ability to simulate native tissue function, hydrogels are potentially well suited for cellular therapy applications. In this study, we have fabricated nanofibrillar cellulose-alginate (NFCA) suture coatings as biomedical devices to help overcome some of the limitations related to cellular therapy, such as low cell survivability and distribution out of target tissue. The addition of sodium alginate 8% (w/v) increased the NFCA hydrogel viscosity, storage and loss moduli by slightly under one order of magnitude, thus contributing significantly to coating strength. Confocal microscopy showed nearly 100% cell viability throughout the 2-week incubation period within and on the surface of the coating. Additionally, typical morphologies in the dual cell culture of spheroid forming HepG2 and monolayer type SK-HEP-1 were observed. Twelve out of 14 NFCA coated surgical sutures remained intact during the suturing operation with various mice and rat tissue; however, partial peeling off was observed in 2 of the coated sutures. We conclude that NFCA suture coatings could perform as cell-carrier systems for cellular based therapy and post-surgical treatment.
  • Nanoselluloosa-hydrogeelit viljelysalustana hermosolujen tutkimuksessa ja lääkekehityksessä
    (2019-05-22) Vilo, Emilia
     Kemiantekniikan korkeakoulu | Bachelor's thesis
  • Pectin and Mucin Enhance the Bioadhesion of Drug Loaded Nanofibrillated Cellulose Films
    (2018-07-01) Laurén, Patrick; Paukkonen, Heli; Lipiäinen, Tiina; Dong, Yujiao; Oksanen, Timo; Räikkönen, Heikki; Ehlers, Henrik; Laaksonen, Päivi; Yliperttula, Marjo; Laaksonen, Timo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Purpose: Bioadhesion is an important property of biological membranes, that can be utilized in pharmaceutical and biomedical applications. In this study, we have fabricated mucoadhesive drug releasing films with bio-based, non-toxic and biodegradable polymers that do not require chemical modifications. Methods: Nanofibrillar cellulose and anionic type nanofibrillar cellulose were used as film forming materials with known mucoadhesive components mucin, pectin and chitosan as functional bioadhesion enhancers. Different polymer combinations were investigated to study the adhesiveness, solid state characteristics, film morphology, swelling, mechanical properties, drug release with the model compound metronidazole and in vitro cytotoxicity using TR146 cells to model buccal epithelium. Results: SEM revealed lamellar structures within the films, which had a thickness ranging 40–240 μm depending on the film polymer composition. All bioadhesive components were non-toxic and showed high adhesiveness. Rapid drug releasewas observed, as 60–80% of the total amount of metronidazole was released in 30 min depending on the film formulation. Conclusions: The liquid molding used was a straightforward and simple method to produce drug releasing highly mucoadhesive films, which could be utilized in treating local oral diseases, such as periodontitis. All materials used were natural biodegradable polymers from renewable sources, which are generally regarded as safe.
  • Quantified forces between HepG2 hepatocarcinoma and WA07 pluripotent stem cells with natural biomaterials correlate with in vitro cell behavior
    (2019-05-14) Harjumäki, Riina; Nugroho, Robertus Wahyu N.; Zhang, Xue; Lou, Yan Ru; Yliperttula, Marjo; Valle-Delgado, Juan José; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In vitro cell culture or tissue models that mimic in vivo cellular response have potential in tissue engineering and regenerative medicine, and are a more economical and accurate option for drug toxicity tests than animal experimentation. The design of in vivo-like cell culture models should take into account how the cells interact with the surrounding materials and how these interactions affect the cell behavior. Cell-material interactions are furthermore important in cancer metastasis and tumor progression, so deeper understanding of them can support the development of new cancer treatments. Herein, the colloidal probe microscopy technique was used to quantify the interactions of two cell lines (human pluripotent stem cell line WA07 and human hepatocellular carcinoma cell line HepG2) with natural, xeno-free biomaterials of different chemistry, morphology, and origin. Key components of extracellular matrices –human collagens I and IV, and human recombinant laminin-521−, as well as wood-derived, cellulose nanofibrils –with evidenced potential for 3D cell culture and tissue engineering– were analysed. Both strength of adhesion and force curve profiles depended on biomaterial nature and cell characteristics. The successful growth of the cells on a particular biomaterial required cell-biomaterial adhesion energies above 0.23 nJ/m. The information obtained in this work supports the development of new materials or hybrid scaffolds with tuned cell adhesion properties for tissue engineering, and provides a better understanding of the interactions of normal and cancerous cells with biomaterials in the human body.
  • Quantifying the interactions between biomimetic biomaterials – collagen I, collagen IV, laminin 521 and cellulose nanofibrils – by colloidal probe microscopy
    (2019-01-01) Nugroho, Robertus Wahyu N.; Harjumäki, Riina; Zhang, Xue; Lou, Yan Ru; Yliperttula, Marjo; Valle-Delgado, Juan José; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Biomaterials of different nature have been and are widely studied for various biomedical applications. In many cases, biomaterial assemblies are designed to mimic biological systems. Although biomaterials have been thoroughly characterized in many aspects, not much quantitative information on the molecular level interactions between different biomaterials is available. That information is very important, on the one hand, to understand the properties of biological systems and, on the other hand, to develop new composite biomaterials for special applications. This work presents a systematic, quantitative analysis of self- and cross-interactions between films of collagen I (Col I), collagen IV (Col IV), laminin (LN-521), and cellulose nanofibrils (CNF), that is, biomaterials of different nature and structure that either exist in biological systems (e.g., extracellular matrices) or have shown potential for 3D cell culture and tissue engineering. Direct surface forces and adhesion between biomaterials-coated spherical microparticles and flat substrates were measured in phosphate-buffered saline using an atomic force microscope and the colloidal probe technique. Different methods (Langmuir-Schaefer deposition, spin-coating, or adsorption) were applied to completely coat the flat substrates and the spherical microparticles with homogeneous biomaterial films. The adhesion between biomaterials films increased with the time that the films were kept in contact. The strongest adhesion was observed between Col IV films, and between Col IV and LN-521 films after 30 s contact time. In contrast, low adhesion was measured between CNF films, as well as between CNF and LN-521 films. Nevertheless, a good adhesion between CNF and collagen films (especially Col I) was observed. These results increase our understanding of the structure of biological systems and can support the design of new matrices or scaffolds where different biomaterials are combined for diverse biological or medical applications.
  • Synthesis of an Azide-and Tetrazine-Functionalized [60]Fullerene and Its Controlled Decoration with Biomolecules
    (2022-01-11) Gulumkar, Vijay; Tähtinen, Ville; Ali, Aliaa; Rahkila, Jani; Valle-Delgado, Juan José; Äärelä, Antti; Österberg, Monika; Yliperttula, Marjo; Virta, Pasi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Bingel cyclopropanation between Buckminster fullerene and a heteroarmed malonate was utilized to produce a hexakis-functionalized C60 core, with azide and tetrazine units. This orthogonally bifunctional C60 scaffold can be selectively one-pot functionalized by two pericyclic click reactions, that is, inverse electron-demand Diels-Alder and azide-alkyne cycloaddition, which with appropriate ligands (monosaccharides, a peptide and oligonucleotides tested) allows one to control the assembly of heteroantennary bioconjugates.