Jouko Peltonen

• Åbo Akademi University

The proliferation of human cervical cancer (Hela) cells was investigated on a series of nanostructured polymer latex surfaces. The physico-chemical properties of the surfaces, composed of mixtures of polystyrene and acrylonitrile butadiene styrene dispersions, were precisely controlled in the nanoscale range by adjusting the mixing ratio of the com...

Global antimicrobial resistance poses a major threat to human health and is largely driven by bacterial biofilms, which demonstrate significantly greater antibiotic resistance than planktonic bacteria. While most biofilm research targets the development of antibiofilm surfaces, materials that intentionally promote biofilm formation are crucial for...

Inside cover illustration for a recently published paper about utilizing graphene-based materials as anodes in a biophotovoltaic device for green energy production! Sustainable Energy & Fuels Interdisciplinary research for the development of sustainable energy technologies rsc.li/sustainable-energy

Objectives To investigate the impact of simulated gastric acid on the surface properties of lithium disilicate–reinforced glass–ceramics and zirconia-reinforced lithium silicate glass–ceramic after certain polishing and glazing procedures. Materials and methods Four different types of square-shaped specimens (10 × 10 × 2 mm³, n = 13) were manufact...

One-dimensional (1D) nanomaterials of conductive polypyrrole (PPy) are competitive biomaterials for constructing bioelectronics to interface with biological systems. Synergistic synthesis using lignocellulose nanofibrils (LCNF) as a structural template in chemical oxidation of pyrrole with Fe(III) ions facilitates surface-confined polymerization of...

Fabricating bio‐latex colloids with core–shell nanostructure is an effective method for obtaining films with enhanced mechanical characteristics. Nano‐sized lignin is rising as a class of sustainable nanomaterials that can be incorporated into latex colloids. Fundamental knowledge of the correlation between surface chemistry of lignin nanoparticles...

This study introduced a new and unique design of cellulose nanomaterials called as cellulose nanoworms, which exhibit alluring properties for creating sustainable and advanced film structures. These nanoworms, which are...

This work demonstrates the innovative utilisation of sheer exfoliated few-layer graphene and graphene–CNC films as eco-friendly electrodes for efficient current extraction from cyanobacteria, promising advancements in biophotovoltaic applications.

Objectives A tribochemical silica-coating (TSC) method has been developed to improve the adhesion of dental resin composites to various substrates. The method utilizes airborne-particle abrasion using particles having a silica surface and an alumina core. The impact of the TSC method has been extensively studied but less attention has been paid to...

To date, the energy-intensive production and high-water content severely limits nanocellulose applications on a large scale off-site. In this study, adding water-soluble polysaccharides (PS) to achieve an integrated process of water-redispersible nanocellulose production was well established. The addition of PS, in particular carboxymethylated-gala...

Electroconductive composites of graphene and cellulose nanocrystals (CNC) were prepared by direct exfoliation of natural flake graphite in CNC suspensions. Using the scalable high-shear exfoliation method, we show that the environmentally friendly CNC is an excellent graphene stabilizer as we prepared aqueous graphene-CNC dispersions with a high co...

Titanium dioxide (TiO2) is a commonly used electron selective layer in thin-film solar cells. The energy levels of TiO2 align well with those of most light-absorbing materials and facilitate extracting electrons while blocking the extraction of holes. In a device, this separates charge carriers and reduces recombination. In this study, we have eval...

Lithography-based digital light processing (DLP) 3D printing has gained increasing interest in the fabrication of custom-designed hydrogel scaffolds. Current research development calls for the versatility of the bio-based resin formulations...

Four clay materials, namely, bentonite, bleaching earth, attapulgite and sepiolite, were shaped into the cylindrical body by extrusion. Clays were characterized in depth by TEM, SEM-EDX, N2 physisorption, pyridine FTIR, pH measurements, contact angle measurements, ²⁷Al MAS NMR, and the crush test. Catalytic properties were investigated in the citro...

Investigating and understanding the response of microbes to various surfaces requires a versatile parametrisation of the surface, and multiple assays that captures the complexity of the biofilm structures. Here, Staphylococcus aureus biofilm viability, polysaccharide poly-N-acetylglucosamine, and proteins on the cell surface were analysed with agar...

Objective: Clinically used bioceramics have been characterized previously with different kinds of methods and comparison of results have proven to be difficult due to varieties of the material properties of interest. Therefore, in this study we compared clinically commonly used bioceramics of hydroxyapatite and carbonate apatite, two bioactive gla...

High-shear exfoliation of graphite is a cost-effective liquid-phase exfoliation (LPE) method for producing few-layer graphene dispersions. However, the drawbacks of LPE such as low graphene concentrations, long processing times and solvent residuals hamper the scalability of the process and applicability of the dispersions. Here, we demonstrate a f...

A paper-based platform was developed and tested for studies on basic cell culture, material biocompatibility, and activity of pharmaceuticals in order to provide a reliable, robust and low-cost cell study platform. It is based upon a paper or paperboard support, with a nanostructured latex coating to provide an enhanced cell growth and sufficient b...

Medical device-associated staphylococcal infections are a common and challenging problem. However, detailed knowledge of staphylococcal biofilm dynamics on clinically relevant surfaces is still limited. In the present study, biofilm formation of the Staphylococcus aureus ATCC 25923 strain was studied on clinically relevant materials—borosilicate gl...

This work describes the use of a paper substrate for electro-optical detection of toxic hydrogen sulfide (H2S) gas. For electrical detection, a chemiresistive type of gas sensor was developed. Ultrathin gold film electrodes (UTGFE) were produced by physical vapor deposition of gold on nanostructured latex-coated paper substrate. The gas-sensing fil...

We introduce rapid replica molding of ordered, high-aspect-ratio, thiol-ene micropillar arrays for implementation of microfluidic immobilized enzyme reactors (IMERs). By exploiting the abundance of free surface thiols of off-stoichiometric thiol-ene compositions, we were able to functionalize the native thiol-ene micropillars with gold nanoparticle...

Silver nanoparticles (NPs) are known to provide antimicrobial properties for surfaces. However, there are environmental concerns due to reports of toxicity after exposure to the environment during or after end-use. Immobilizing silver NPs to the surface of substrates could ensure that particles are readily available for antibacterial activity with...

To achieve full utilization of lignocellulosic biomass and easy integration of nanomaterials production, it is essential to develop an efficient fractionation to overcome the highly recalcitrant nature of lignocellulose and facilitate the subsequent valuable conversion. Herein, in a combined process based on the formic acid rapid-fractionation of b...

Objectives: This study aimed to investigate the effects of using hydroxyl apatite functionalized calcium carbonate (FCC) particles on occluding dentinal tubules. Methods: Dentine specimens extracted from eighteen human molars with exposed dentinal tubules were divided into three groups (n 1⁄4 6/group): a) Cut surface with smear layer; b) EDTA (sm...

Silver nanoparticles deposited on surfaces can provide an antibacterial effect with potential uses in, for example, healthcare settings. However, release of nanoparticles and their potential exposure to the environment is of concern. The current work demonstrates a continuous synthesis that simultaneously deposits silver nanoparticles onto plastic...

Methylamine (MA) is highly toxic even at low concentrations. The current U.S.A. Occupational Safety and Health Administration Permissible Exposure Limit (OSHA PEL) is 10 ppm in the gas phase. In this study we have developed low-cost, robust and stable copper sulphide film on flexible plastic and paper substrate. The sensitivity of the film towards...

In this study hierarchically-structured latex polymer coatings and self-supporting films were characterised and their suitability for cell growth studies was tested with Human Dermal Fibroblasts (HDF). Latex can be coated or printed on rigid or flexible substrates thus enabling high-throughput fabrication. Here, coverslip glass substrates were coat...

Aim of the study was to evaluate apatite forming ability and ion dissolution of bioactive glass-ceramic (BGC) particles from novel polydimethylsiloxane (PDMS) based endodontic sealer Guttaflow Bioseal. Firstly, water sorption and solubility were determined for Guttaflow 2 and Guttaflow Bioseal (GB), the latter containing BGC filler particles. Miner...

2D patterns of photothermally responsive near‐infrared (NIR) absorbing gold nanostars (GNS), coated with multiple charged polymer layers, are inkjet‐printed on a glass surface. The shape of the localized surface plasmon resonance (LSPR) NIR absorption bands in the printed patterns loses its peaked form due to plasmon coupling, unless GNS are envelo...

Inkjet-printing of metal nanoparticles is a particularly promising technique for the fabrication and modification of surfaces with a multifunctional nature. Recently copper sulfide nanoparticles (CuS NPs) have attracted wide interest due to a range of valuable properties including long term stability, photo-thermal activity, ease of synthesis and l...

Low-cost and robust hydrogen sulfide (H2S) gas sensors can be utilized in different industrial applications. Earlier we have demonstrated an inexpensive wirelessly readable copper acetate based H2S gas sensor which was successfully employed for monitoring the quality of raw poultry. In this study we have thoroughly investigated and optimized the pe...

Correlative light and electron microscopy (CLEM) allows combining the advantages of fluorescence microscopy and electron microscopy for cell imaging. Rare phenomenon expressing cells can be studied by specifically tagged fluorophores with fluorescence microscopy. Subsequently, cells can be fixed and ultra-structural details can be studied with tran...

Unsymmetrical diynes containing N-arylcarbamate groups in the hydrophobic part and hydroxymethylene groups in the hydrophilic part of the molecules were synthesized and studied. The Langmuir monolayer formation process was followed by Brewster angle microscopy (BAM). The Langmuir-Schaefer monolayer films, transferred on solid substrates (quartz or...

Approaches to increase the efficiency in developing drugs and diagnostics tools, including new drug delivery and diagnostic technologies, are needed for improved diagnosis and treatment of major diseases and health problems such as cancer, inflammatory diseases, chronic wounds, and antibiotic resistance. Development within several areas of research...

This chapter reviews the recent advances in achieving green electronics using cellulosic paper and fibers as a substrate for electronics. It focuses on the paper substrate, individual component development, and the use of paper for sensing purposes in both analytical and point-of-care applications. While using paper as a substrate is difficult, sin...

The traditional method to isolate cellulose nanocrystals (CNCs) is to subject cellulosic materials to strong acid hydrolysis by mineral acids, which usually cause problems such as corrosion of equipment, the need of large amount of water, the difficulty of acid recovery, and over-degradation of cellulose. Thus, a green and sustainable approach for...

Self-assembled monolayers (SAMs) as model surfaces were linked onto planar gold films thorough lipoic acid or disulfide groups. The molecules used were polyethylene glycol (EG-S-S), N-[tris-(hydroxymethyl)methyl]acrylamide polymers with and without lipoic acid (Lipa-pTHMMAA and pTHMMAA) and a lipoic acid triazine derivative (Lipa-MF). All the layer...

Solid topochemical photopolymerization (STP) of Langmuir-Schaefer films of a new class of unsymmetrical diynes, containing N-arylcarbamate groups in the hydrophobic part and hydroxymethylene groups in the hydrophilic part of the molecules was examined. In addition, the monomeric Langmuir monolayer formation was studied by Brewster angle microscopy...

Sulfated zirconia hydroxide shaping by extrusion is studied based on elucidating the impact of zeta-potential and rheological characteristics on physical and chemical properties of technical catalysts. Zeta potential measurements of sulfated zirconium hydroxide prior and after poly(vinyl alcohol) (PVA) additions were made. Rheological curves of sul...

Printing technology serves as a valuable alternative for improving the flexibility and dosing precision of drugs in the fabrication of solid dosage forms. Nevertheless, there is a need for applicable control methods to ensure the final quality of printed products. In this study the use of attenuated total reflectance Fourier transform infrared (ATR...

Self-assembled monolayers (SAMs) as model surfaces were linked onto planar gold films thorough lipoic acid or disulfide groups. The molecules used were polyethylene glycol (EG-S-S), N-[tris-(hydroxymethyl)methyl]acrylamide polymers with and without lipoic acid (Lipa-pTHMMAA and pTHMMAA) and a lipoic acid triazine derivative (Lipa-MF). All the layer...

The integration of flexible electronic sensors in clinical diagnostics is visioned to significantly reduce the cost of many diagnostic tests and ultimately make healthcare more accessible. This study concentrates on the characterization of inkjet-printed bio-functionalized polythiophene films on paper-based ultrathin gold film (UTGF) electrodes and...

Different length scale alterations in topography, surface texture, and symmetry are known to evoke diverse cell behavior, including adhesion, orientation, motility, cytoskeletal condensation, and modulation of intracellular signaling pathways. In this work, self-supported latex films with well-defined isotropic/anisotropic surface features and hier...

Adsorption of proteins and adhesion of bacteria to a surface is affected by chemical and physical interactions. In this study, polymer coatings and their ability to adsorb avidin and Staphylococcus aureus were investigated. The surface chemistry and topography of the polymer coatings was modified by changing the weight ratio of the hydrophobic poly...

Fabrication of nanoperforated TiO2 thin films (NP-TiO2) on various substrates utilizing evaporation-induced self-assembly has been widely reported during recent years. For many applications, such as solar cells and gas sensors, it would be beneficial if the active material could be deposited onto a desired area or in the form of a pattern or array....

There are several ways for improving product safety for fibre-based food packages. In this paper the project “Safe food packages of the future” is discussed. The focus in this project was both in package functionality and food safety. The main objective of the project was to improve package and food safety by the means of functionality of paperboar...

A roll-to-roll compatible fabrication process of porous silicon (pSi) based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive response...

The aim of this study was to prepare printable inks of the poorly water soluble drug indomethacin (IMC), fabricate printed systems with flexible doses and investigate the effect of ink excipients on the printability, dissolution rate and the solid state of the drug. A piezoelectric inkjet printer was used to print 1x1 cm(2) squares onto a paper sub...

Ultrathin gold films (UTGFs) were fabricated on a nanostructured latex-coated paper substrate by physical vapour deposition (PVD) with the aim to provide low-cost and flexible conductive electrodesin paper-based electronics. Morphological, electric and optical properties of UTGFs were dependent on the deposited film thickness. In addition, UTGFs we...

This paper presents the sub-ppm level electrical detection of H2S gas at room temperature using printed copper acetate-gold nanoparticle composite films. The excellent sensitivity of these films towards H2S can be attributed to the catalytic activity of gold nanoparticles in combination with the plasma oxidation of copper acetate films.

The main goal of the current work was to investigate the possible use of flexographic printing for the conversion of nanosuspensions into solid dosage forms. Aqueous nanosuspensions of indomethacin (IND) and itraconazole (ITR) with Poloxamer 407 as the stabilizer agent were prepared by wet ball-milling. The nanosuspensions were flexographically pri...

The aim of this work was to study the activity and functionality of laccase incorporated into laboratory-coated surface-sized paper. The effects of the physicochemical properties of the studied sized paper grades (permeability, porosity, and wetting) on the enzyme activity were studied. The enzymatic activity of laccase was measured either by follo...

Cement pastes were studied using conventional rheological methods. The effect of different types of functional fillers on the rheological properties and hydration rate of the pastes was analysed. The fillers were found to have varying chemistry and therefore surface properties. Porous titania particles raised the cohesive energy of the paste signif...

More flexible yet robust manufacturing solutions are needed in the pharmaceutical industry. Tablet compaction is no longer the obvious choice for commercial-scale processing of innovative drug delivery systems. Engineering solutions have gained wide attention in the pharmaceutical industry. Technical innovations within printing are considerable sol...

Patterning of functionalized polymeric surfaces enables the adjustment of their characteristics and use in novel applications. We prepared breath figure (BF) films from three semifluorinated diblock copolymers, which all are composed of a polystyrene block and a semifluorinated one to compare their surface properties. “Click” chemistry was employed...

The suitability of paper-based arrays for biofilm formation studies by Staphylococcus aureus is demonstrated. Laboratory-coated papers with different physicochemical properties were used as substrates. The array platform was fabricated by patterning the coated papers with vinyl-substituted polydimethylsiloxane (PDMS) -based ink. The affinity of bac...

Controlling the nanostructure of polymeric films using cost-effective deposition methods, like inkjet printing, has proven challenging due to the relative low resolution of such techniques. In this study, we combine inkjet printing with the use of nanopatterned substrates composed of TiO2 thin films on top of silicon wafers (NP-TiO2) for the prepar...

This work describes the development of a stable dispersion which is suitable for roll-to-roll printing of a film exhibiting hydrogen sulfide (H2S) gas sensing functionality. The dispersions are made from copper chloride in combination with either citric acid or citric acid and polyaniline (PANI). Aqueous PANI dispersions together with copper chlori...

Specific interactions of extracellular matrix proteins with cells and their adhesion to the substrate are important for cell growth. A nanopatterned latex-coated paper substrate previously shown to be an excellent substrate for cell adhesion and 2D growth was studied for directed immobilization of proteins. The nanostructured latex surface was form...

We have used phase-separated poly(3-hexyltiophene) (P3HT)/poly(L-lactic acid) (PLLA) blends to fabricate low-voltage ion-modulated transistors on a rough paper substrate. The semiconductor and insulator are mixed together in a solution and spin casted onto the paper substrate. Owing to their different solubilities and surface energies the P3HT and...

In this study, two different supramolecular recognition architectures for impedimetric detection of DNA hybridization have been formed on disposable paper-supported inkjet-printed gold electrodes. The gold electrodes were fabricated using a gold nanoparticle based ink. The first recognition architecture consists of subsequent layers of biotinylated...

Two silane-based hybrid coatings were developed for surface modification of paper samples with an attempt to improve the hydrophobic properties of the paper surfaces. A phenolic resin was used along with the sol–gel coatings to impregnate the paper samples before they were pressed on to plywood surfaces. The surface characteristics of the sol–gel-c...

Introduction: There has been increased activity in the field recently regarding the development and research on various printing techniques in fabrication of dosage forms and drug delivery systems. These technologies may offer benefits and flexibility in manufacturing, potentially paving the way for personalized dosing and tailor-made dosage forms...

Small antimicrobial β(2,2)-amino acid derivatives (Mw < 500 Da) are reported to display high antibacterial activity against suspended Gram-positive strains combined with low hemolytic activity. In the present study, the anti-biofilm activity of six β(2,2)-amino acid derivatives (A1-A6) against Staphylococcus aureus (ATCC 25923) was investigated. Th...

The purpose of this study was to formulate printable dosage forms for a poorly soluble drug (piroxicam; PRX) and to gain understanding of critical parameters to be considered during development of such dosage forms. Liquid formulations of PRX were printed on edible paper using piezoelectric inkjet printing (PIJ) and impression printing (flexography...

Background: Cheap, reliable, point-of-care diagnostics is a necessity for the growing and aging population of the world. Paper substrate and printing method, combined together, are the cheapest possible method for generating high-volume diagnostic sensor platforms. Electrical transduction tools also minimize the cost and enhance the simplicity of...

The primary goal of the current work was to study the applicability of precision inkjet printing in fabrication of personalized doses of active pharmaceutical ingredients (APIs). Loperamide hydrochloride (LOP) and caffeine (CAF) were used as model compounds. Different doses of the drugs in a single dosage unit were produced, using a drop-on-demand...

A stable liposome-based time-resolved luminescence resonance energy transfer (TR-LRET) assay was developed based on the interaction of biotinylated lipids and streptavidin. Eu(3+) ion chelated to 4,4,4-trifluoro-1-(2-naphthalenyl)-1,3-butanedione and trioctylphosphine oxide was incorporated into liposomes. Acceptor-labeled streptavidin bound to bio...

The fabrication concept for a low-cost sensor device using reduced graphene oxide (rGO) as the sensing material on a porous paper substrate is presented. The sensors were characterized using conductivity and capacitance measurements, atomic force microscopy and X-ray photoelectron spectroscopy. The effects of different reducing agents, graphene oxi...

In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecula...

The use of paper-based test platforms in cell culture experiments is demonstrated. The arrays used for 2D cell cultures were prepared by printing patterned structures on a paper substrate by using a hydrophobic PDMS ink. The non-printed, PDMS-free areas formed the array for the cell growth experiments. Cell imaging was enabled by using a lipophilic...

An electrode platform printed on a recyclable low-cost paper substrate was characterized using cyclic voltammetry. The working and counter electrodes were directly printed gold-stripes, while the reference electrode was a printed silver stripe onto which an AgCl layer was deposited electrochemically. The novel paper-based chips showed comparable pe...

Packaging safety is a very broad topic covering the whole packaging value chain. Safety aspects arerecognized when packaging materials are selected for a certain purpose, when packaging materials areconverted into packages, when packages are filled and closed, when packages are distributed, whenthese are used at home and finally when recycled. In t...

Printing technologies specifically digital inkjet printing, offer possibilities in the production of individualized medicines. The main advantage of inkjet printing includes the ability to dispense uniform droplets in the picoliter range with high degree of accuracy to allow dose personalization. The pharmaceutical ink formulation has to be designe...

In this work, the feasibility of porous silicon particles for producing printed humidity sensors is examined. A proof of concept is provided by producing fully functional humidity sensors on a glass substrate by drop casting a particle solution on top of inkjet printed silver electrodes. Sensor sensitivity towards changes in relative humidity is ex...

Medicines are most often oral solid dosage forms made into tablets or capsules, and there is little room for individualized doses. The drug substance and additives are processed through multiple production phases, including complex powder handling steps. In drug manufacturing, the control of the solid-state properties of active pharmaceutical ingre...

Fully printed copper acetate based H2S sensors on paper are presented. The sensors show several orders of magnitude change in resistance (>108) when exposed to 10 ppm of H2S gas at room temperature. The effect of different solvents, film thickness and substrates (absorbing and nonabsorbing) have been studied to optimize the sensor response. The lar...

Wood has played a major role throughout human history. Strong and versatile, the earliest humans used wood to make shelters, cook food, construct tools, build boats, and make weapons. Recently, scientists, politicians, and economists have renewed their interest in wood because of its unique properties, aesthetics, availability, abundance, and perha...