Tekidag AB

Linköping, Sweden

Tekidag AB

Linköping, Sweden
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Imani R.,University of Ljubljana | Pazoki M.,Uppsala University | Tiwari A.,Linköping University | Tiwari A.,Tekidag AB | And 4 more authors.
Nanoscale | Year: 2015

Novel mesoporous TiO2@DNA nanohybrid electrodes, combining covalently encoded DNA with mesoporous TiO2 microbeads using dopamine as a linker, were prepared and characterised for application in supercapacitors. Detailed information about donor density, charge transfer resistance and chemical capacitance, which have an important role in the performance of an electrochemical device, were studied by electrochemical methods. The results indicated the improvement of electrochemical performance of the TiO2 nanohybrid electrode by DNA surface functionalisation. A supercapacitor was constructed from TiO2@DNA nanohybrids with PBS as the electrolyte. From the supercapacitor experiment, it was found that the addition of DNA played an important role in improving the specific capacitance (Cs) of the TiO2 supercapacitor. The highest Cs value of 8 F g-1 was observed for TiO2@DNA nanohybrids. The nanohybrid electrodes were shown to be stable over long-term cycling, retaining 95% of their initial specific capacitance after 1500 cycles. © 2014 The Royal Society of Chemistry.

Patra H.K.,Linköping University | Sharma Y.,Japan International Center for Materials Nanoarchitectonics | Islam M.M.,Karolinska Institutet | Jafari M.J.,Linköping University | And 7 more authors.
Nanoscale | Year: 2016

To cope with the rapid evolution of the tissue engineering field, it is now essential to incorporate the use of on-site responsive scaffolds. Therefore, it is of utmost importance to find new 'Intelligent' biomaterials that can respond to the physicochemical changes in the microenvironment. In this present report, we have developed biocompatible stimuli responsive polyaniline-multiwalled carbon nanotube/poly(N-isopropylacrylamide), (PANI-MWCNT/PNIPAm) composite nanofiber networks and demonstrated the physiological temperature coordinated cell grafting phenomenon on its surface. The composite nanofibers were prepared by a two-step process initiated with an assisted in situ polymerization followed by electrospinning. To obtain a smooth surface in individual nanofibers with the thinnest diameter, the component ratios and electrospinning conditions were optimized. The temperature-gated rearrangements of the molecular structure are characterized by FTIR spectroscopy with simultaneous macromolecular architecture changes reflected on the surface morphology, average diameter and pore size as determined by scanning electron microscopy. The stimuli responsiveness of the nanofibers has first been optimized with computational modeling of temperature sensitive components (coil-like and globular conformations) to tune the mechanism for temperature dependent interaction during in situ scaffolding with the cell membrane. The nanofiber networks show excellent biocompatibility, tested with fibroblasts and also show excellent sensitivity to inflammation to combat loco-regional acidosis that delay the wound healing process by an in vitro model that has been developed for testing the proposed responsiveness of the composite nanofiber networks. Cellular adhesion and detachment are regulated through physiological temperature and show normal proliferation of the grafted cells on the composite nanofibers. Thus, we report for the first time, the development of physiological temperature gated inflammation-sensitive smart biomaterials for advanced tissue regeneration and regenerative medicine. © 2016 The Royal Society of Chemistry.

Ashaduzzaman M.,Linköping University | Ashaduzzaman M.,University of Dhaka | Anto Antony A.,Linköping University | Arul Murugan N.,KTH Royal Institute of Technology | And 4 more authors.
Biosensors and Bioelectronics | Year: 2015

Regeneration is a key goal in the design of immunosensors. In this study, we report the temperature-regulated interaction of N-isopropylacrylamide (PNIPAAm) functionalised cardiac troponin T (cTnT) with anti-cTnT. Covalently bonded PNIPAAm on an anti-cTnT bioelectrode showed on/off-switchability, regeneration capacity and temperature triggered sensitivity for cTnT. Above the lower critical solution temperature (LCST), PNIPAAm provides a liphophilic microenvironment with specific volume reduction at the bioelectrode surface, making available binding space for cTnT, and facilitating analyte recognition. Computational studies provide details about the structural changes occurring at the electrode above and below the LCST. Furthermore, free energies associated with the binding of cTnT with PNIPAAm at 25 (δGcoil=-6.0Kcal/mole) and 37°C (δGglobular=-41.0kcal/mole) were calculated to elucidate the interaction and stability of the antigen-antibody complex. The responsiveness of such assemblies opens the way for miniaturised, smart immuno-technologies with 'built-in' programmable interactions of antigen-antibody upon receiving stimuli. © 2015 Elsevier B.V.

Sharma D.,Durban University of Technology | Ashaduzzaman M.,Linköping University | Golabi M.,Linköping University | Shriwastav A.,Indian Institute of Technology Kanpur | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Molecular imprinting generates robust, efficient, and highly mesoporous surfaces for biointeractions. Mechanistic interfacial interaction between the surface of core substrate and protein corona is crucial to understand the substantial microbial toxic responses at a nanoscale. In this study, we have focused on the mechanistic interactions between synthesized saponin imprinted zinc oxide nanohoneycombs (SIZnO NHs), average size 80-125 nm, surface area 20.27 m2/g, average pore density 0.23 pore/nm and number-average pore size 3.74 nm and proteins corona of bacteria. The produced SIZnO NHs as potential antifungal and antibacterial agents have been studied on Sclerotium rolfsii (S. rolfsii), Pythium debarynum (P. debarynum) and Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), respectively. SIZnO NHs exhibited the highest antibacterial (∼50%) and antifungal (∼40%) activity against Gram-negative bacteria (E. coli) and fungus (P. debarynum), respectively at concentration of 0.1 mol. Scanning electron spectroscopy (SEM) observation showed that the ZnO NHs ruptured the cell wall of bacteria and internalized into the cell. The molecular docking studies were carried out using binding proteins present in the gram negative bacteria (lipopolysaccharide and lipocalin Blc) and gram positive bacteria (Staphylococcal Protein A, SpA). It was envisaged that the proteins present in the bacterial cell wall were found to interact and adsorb on the surface of SIZnO NHs thereby blocking the active sites of the proteins used for cell wall synthesis. The binding affinity and interaction energies were higher in the case of binding proteins present in gram negative bacteria as compared to that of gram positive bacteria. In addition, a kinetic mathematical model (KMM) was developed in MATLAB to predict the internalization in the bacterial cellular uptake of the ZnO NHs for better understanding of their controlled toxicity. The results obtained from KMM exhibited a good agreement with the experimental data. Exploration of mechanistic interactions, as well as the formation of bioconjugate of proteins and ZnO NHs would play a key role to interpret more complex biological systems in nature. © 2015 American Chemical Society.

Parlak O.,Linköping University | Ashaduzzaman Md.,Linköping University | Ashaduzzaman Md.,Bangladesh University | Kollipara S.B.,Linköping University | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The engineering of bionanointerfaces using stimuli-responsive polymers offers a new dimension in the design of novel bioelectronic interfaces. The integration of electrode surfaces with stimuli-responsive molecular cues provides a direct control and ability to switch and tune physical and chemical properties of bioelectronic interfaces in various biodevices. Here, we report a dual-responsive biointerface employing a positively responding dual-switchable polymer, poly(NIPAAm-co-DEAEMA)-b-HEAAm, to control and regulate enzyme-based bioelectrocatalysis. The design interface exhibits reversible activation-deactivation of bioelectrocatalytic reactions in response to change in temperature and in pH, which allows manipulation of biomolecular interactions to produce on/off switchable conditions. Using electrochemical measurements, we demonstrate that interfacial bioelectrochemical properties can be tuned over a modest range of temperature (i.e., 20-60°C) and pH (i.e., pH 4-8) of the medium. The resulting dual-switchable interface may have important implications not only for the design of responsive biocatalysis and on-demand operation of biosensors, but also as an aid to elucidating electron-transport pathways and mechanisms in living organisms by mimicking the dynamic properties of complex biological environments and processes. © 2015 American Chemical Society.

Parlak O.,Linköping University | Turner A.P.F.,Linköping University | Tiwari A.,Linköping University | Tiwari A.,Tekidag AB
Journal of Materials Chemistry B | Year: 2015

Switchable interfaces can deliver functionally reversible reactivity with their corresponding analytes, which allows one to positively respond to the activity of biological elements, including enzymes and other biomolecules, through an encoded stimulus. We have realized this by the design of stimuli-responsive graphene interfaces for the pH-encoded operation of bioelectronics. Herein, we have demonstrated stimuli-responsive graphene interfaces for the pH-encoded operation of bioelectronics. The resulting switchable interfaces are capable of the highly specific, on-demand operation of biosensors, which has significant potential in a wide range of analytical applications. © The Royal Society of Chemistry 2015.

Mishra S.,Linköping University | Mishra S.,University of the Free State | Ashaduzzaman M.,Linköping University | Ashaduzzaman M.,Dhaka University of Engineering and Technology | And 7 more authors.
Biosensors and Bioelectronics | Year: 2016

Graphene interfaces with multi-stimuli responsiveness are of particular interest due to their diverse super-thin interfacial behaviour, which could be well suited to operating complex physiological systems in a single miniaturised domain. In general, smart graphene interfaces switch bioelectrodes from the hydrophobic to hydrophilic state, or vice versa, upon triggering. In the present work, a stimuli encoded zipper-like graphene oxide (GrO)/polymer interface was fabricated with in situ poly(N-isopropylacrylamide-co-diethylaminoethylmethylacrylate), i.e., poly(NIPAAm-co-DEAEMA) directed hierarchical self-assembly of GrO and glucose oxidase (GOx). The designed interface exhibited reversible on/off-switching of bio-electrocatalysis on changing the pH between 5 and 8, via phase transition from super hydrophilic to hydrophobic. The study further indicated that the zipper-like interfacial bioelectrochemical properties could be tuned over a modest change of temperature (i.e., 20-40. °C). The resulting auto-switchable interface has implications for the design of novel on/off-switchable biodevices with 'in-built' self-control. © 2016 Elsevier B.V.

Thakur S.,Himachal Pradesh University | Rai R.,Himachal Pradesh University | Sharma S.,Ferroelectric Research Laboratory | Tiwari A.,Linköping University | Tiwari A.,Tekidag AB
Advanced Materials Letters | Year: 2016

Polycrystalline samples of (K0.45Na0.45Li0.1NbO3)1-x-(Ba0.96La0.04Ti0.815Mn0.0025 Nb0.0025Zr0.18 O3)x ceramics (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) were prepared by using a high temperature solid state reaction technique. The XRD patterns of the BLTMNZ doped KNLN at room temperature with x = 0.7 have pure pervoskite phase with tetragonal structure at room temperature and have maximum value of dielectric constant at x = 0.9. Detailed studies of dielectric and impedance properties of the materials in a wide range of frequency (100Hz-1MHz) and temperatures (30 - 500 °C) showed that properties are strongly temperature and frequency dependent. The plots of Z" and M" versus frequency at various temperatures show peaks in the higher temperature range (> 300 °C). The compounds show dielectric relaxation, which is found to be of non-Debye type and the relaxation frequency shifted to higher side with increase in temperature. The Nyquist plot and conductivity studies showed the NTCR character of samples. Copyright © 2016 VBRI Press.

Parlak O.,Linköping University | Beyazit S.,Compiègne University of Technology | Tse-Sum-Bui B.,Compiègne University of Technology | Haupt K.,Compiègne University of Technology | And 4 more authors.
Nanoscale | Year: 2016

The ability to program and mimic the dynamic microenvironment of living organisms is a crucial step towards the engineering of advanced bioelectronics. Here, we report for the first time a design for programmable bioelectronics, with 'built-in' switchable and tunable bio-catalytic performance that responds simultaneously to appropriate stimuli. The designed bio-electrodes comprise light and temperature responsive compartments, which allow the building of Boolean logic gates (i.e. "OR" and "AND") based on enzymatic communications to deliver logic operations. © 2016 The Royal Society of Chemistry.

Kumari P.,Shoolini University of Biotechnology and Management Sciences | Rai R.,Shoolini University of Biotechnology and Management Sciences | Sharma S.,Ferroelectric Research Laboratory | Shandilya M.,Shoolini University of Biotechnology and Management Sciences | And 2 more authors.
Advanced Materials Letters | Year: 2015

Lead based piezoelectric perovskite materials are well known for their excellent piezoelectric properties, which are extensively used in industrial applications. Though, considering the toxicity of lead and its compounds, there is a general awareness for the development of environmental friendly lead-free materials as evidenced from the legislation passed by the European Union in this effect. The different class of materials is now being considered as potentially attractive alternatives to lead zirconate titanate (PZT) based perovskites for various applications. In this review, we review the progresses made on lead-free piezoelectric materials emphasizing on their synthesis, structure-property correlation, etc. Advancement of the various piezo systems such as bismuth sodium titanate, alkali niobates etc. and non-perovskites for example bismuth layer-structured ferroelectrics has been deliberated. It is found that some lead-free compositions show stable piezoelectric responses though they are not as high as the PZT system. This subject is of current interest to the ceramic researchers worldwide as evidenced from the large number of research publications and has motivated us to come out with a critical over view the field. This article would drive to the researchers to advance the piezoelectric properties of the non-lead based perovskite compounds to achieve materials at par with the PZT system. © 2015 VBRI Press.

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