Photo-assisted inkjet printing of antibodies onto cellulose for the eco?-friendly preparation of immunoassay membranes

International audienceThe current global issues have stimulated the search for both ecologically and economically friendly (eco?-friendly) materials and processes. As a sustainable and affordable biopolymer, cellulose is an ideal material for developing diagnostic devices. Recently, paper-based bioanalytical devices have trended towards three-dimensional microfluidic platforms allowing multiplex diagnosis. This technological mutation now challenges the production process of those devices. The whole design, as well as the biosensing material immobilization, should be as eco?-friendly as possible. To this end, the biomolecule immobilization process presented here combines a photolinker-free photografting procedure with inkjet printing which is a versatile and environmentally friendly dispensing method. While many printing cycles are usually achieved to get efficient immune answers, only one to five printing passes were sufficient in this study. Antibodies have been successfully printed and immobilized onto paper sheets. These membranes were further used to perform lateral flow immunoassays. The visual detection limits observed were identical to those usually displayed by the classical dispensing method, regardless the membrane material. The process developed herein is simple, time and cost-saving as well as environmentally friendly. More generally, it is a powerful tool for robust and abundant immobilization of chemical-sensitive proteins onto various cellulose-based papers and according to complex designs

One-step and eco-friendly modification of cellulose membranes by polymer grafting

International audienceThe increasing environmental awareness has stimulated the use of bio-based materials and processes. As an affordable and sustainable biopolymer, cellulose is an ideal engineering material. Beyond paper, cellulose finds applications in many areas such as composites, electronics and drug delivery. To fulfil these new functions, cellulose needs to acquire new properties, which is commonly done by graft polymerization of acrylic compounds. While cellulose modification is usually performed through complex and expensive procedures, the diazonium-based polymer grafting procedure presented here was performed in water, at room temperature, in a short single step. Cellulose sheets have been successfully grafted with several acrylic polymers, first globally through a dipping procedure and then locally by inkjet printing. The process developed herein is simple, eco-friendly and mostly time and cost-saving. More generally, it is a powerful tool for easy, robust and patterned graft copolymerization of cellulose sheets with various acrylic monomers and even bio-based monomer

Cellulose: from biocompatible to bioactive material

International audienceSince the papyri, cellulose has played a significant role in human culture, especially as paper. Nowadays, this ancient product has found new scientific applications in the expanding sector of paper-based technology. Among paper-based devices, paper-based biosensors raise a special interest. The high selectivity of biomolecules for target analytes makes these sensors efficient. Moreover, simple paper-based detection devices do not require hardware or specific technical skill. They are inexpensive, rapid, user-friendly and therefore highly promising for providing resource-limited settings with point-of-care diagnostics. The immobilization of biomolecules onto cellulose is a key step in the development of these sensing devices. Following an overview of cellulose structural features and physicochemical properties, this article reviews current techniques for the immobilization of biomolecules on paper membranes. These procedures are categorized into physical, biological and chemical approaches. There is no universal method for biomolecule immobilization. Thus, for a given paper-based biochip, each strategy can be considered

MODIFICATION SIMPLE, BIOCOMPATIBLE ET ROBUSTE DE MEMBRANES DE CELLULOSE POUR LA PREPARATION ECOLOGIQUE ET ECONOMIQUE DE DISPOSITIFS D'IMMUNOANALYSE

Since the papyri, cellulose has played a significant role in human culture, especially as paper. Nowadays, this ancient product has found new applications in the expanding sector of bioactive paper. Simple paper-based detection devices such as lateral flow immunoassays (LFIAs) are inexpensive, rapid, userfriendly and therefore highly promising for providing resource-limited settings with point-of-care diagnostics. Recently, paper-based biosensing technology has trended towards three-dimensional microfluidic devices and multiplexed assay platforms. Yet, many multiplexed paper-based biosensors implement methods incompatible with the conventional LFIA carrier material: nitrocellulose. It thus tends to be replaced by pure cellulose. This major material change implies to undertake a covalent immobilization of biomolecules on cellulose which preserves their biological activity. Furthermore, the current global issues have stimulated the search for both ecologically and economically friendly (eco²-friendly) materials and processes. As a sustainable and affordable biopolymer, cellulose is an ideal material for developing diagnostic devices. However, the frame material is not the only aspect to consider. The whole device design and production, as well as the biosensing material immobilization or the non-sensing membranes treatment, should be as eco²-friendly as possible. Hence, the spatially controlled modification of cellulose surface seems crucial in the development of such devices since it enables to save expensive matter and to pattern surface properties. In any case, modification procedures should abide by the economic and ecological objectives aforementioned.In this perspective, three processes allowing easy, robust and sustainable modification of cellulose sheets were developed. All are environmentallyfriendly, simple, time and cost-saving, and versatile.The first procedure is a functionalization of cellulose membranes for covalent antibody immobilization. While cellulose chemical modification is usuallyoperated under harsh conditions in organic solvents, the diazonium-based procedure developed was performed in water, at room temperature, in a single step. Paper sheets have thus been modified and bear different chemical functions which enable to graft biomolecules by common bioconjugatetechniques and to perform LFIAs.The second is a chemical-free photoimmobilization procedure which allowed antibodies to be immobilized on cellulose without any photocouplingintermediate nor any biomolecule or substrate pretreatment. This immobilization technique was further combined to inkjet printing to localize theantibodies according to any pattern desired. Native antibodies have thus been printed and immobilized on paper sheets which therefore enable toperform LFIAs. Membranes’ performances were evaluated in terms of visual detection limit and challenged nitrocellulose performances.The third is a modification of cellulose membranes by polymer grafting. Unlike the two previous processes, this technique was developed in order toincrease the functionality of the non-sensing cellulose parts of paper-based devices. Yet, it may be employed as another functionalization method forcovalent antibody immobilization on cellulose. While cellulose graft copolymerization is usually performed through complex and expensive procedures,the diazonium-based approach employed was performed in water, at room temperature, in a short single step. Cellulose sheets have thus been graftedwith several acrylic polymers, first globally through a dipping procedure and then locally by inkjet printing.All the strategies developed herein would be helpful to immobilize sensitive proteins on selected specific areas of cellulose sheets. More generally,these are powerful tools for easy and rapid modulation of cellulose surface properties according to complex designs, under soft and biocompatibleconditions.Depuis le papyrus, la cellulose a tenu un rôle important dans notre culture, en particulier comme papier. Aujourd’hui, ce produit ancien trouve denouvelles applications dans le secteur des papiers bioactifs. Des dispositifs de détection faits de papier tels que les bandelettes sont peu coûteux,rapides, faciles à utiliser, et donc très prometteurs pour le diagnostic de terrain dans les zones reculées. Récemment, les biocapteurs papier ont évoluévers des dispositifs microfluidiques 3D et des plateformes multiplexées. Or, le développement de ces biocapteurs papier multiplexés fait souvent appel àdes méthodes incompatibles avec le matériau classique des bandelettes : la nitrocellulose. Celle-ci tend donc à être remplacée par la cellulose. Ce changement de matériau implique la mise en oeuvre d’une immobilisation covalente des biomolécules qui préserve leur activité biologique.Par ailleurs, les enjeux mondiaux actuels incitent à se tourner vers des matériaux et procédés à la fois respectueux de l’environnement et rentableséconomiquement. La cellulose est un polymère naturel abondant et donc un matériau idéal pour le développement de dispositifs de diagnostic.Toutefois, le matériau support n’est pas le seul aspect à considérer. L’ensemble de la conception du dispositif, l’immobilisation des agents de capture, letraitement des membranes, tout doit répondre aux défis écologiques et économiques. La modification localisée des surfaces de cellulose semble alorscruciale puisqu’elle permet d’économiser des composés coûteux et de moduler localement les propriétés de surface.Dans ce contexte, trois procédés de modification facile et durable de feuilles de cellulose ont été développés. Tous sont respectueux del’environnement, simples, polyvalents et économes aussi bien en temps qu’en argent.Le premier est une procédure de fonctionnalisation de membranes de cellulose pour l’immobilisation covalente d’anticorps. Tandis que la modificationchimique de la cellulose se fait habituellement dans des conditions rudes et dans des solvants organiques, la méthode développée ici a été réalisée dans l’eau, à température ambiante, en une seule étape. Des feuilles de papier ont ainsi été modifiées, portant alors différentes fonctions chimiquespermettant de greffer des biomolécules par des techniques de bioconjugaison classiques. Elles ont ensuite été testées comme bandelettes.Le second est une procédure de photoimmobilisation sans produit chimique qui permet d’immobiliser des anticorps sur la cellulose sans aucunintermédiaire de couplage ni aucun prétraitement des biomolécules ou du substrat. Cette technique a été combinée à l’impression jet d’encre pourlocaliser les anticorps selon tout motif désiré. Des anticorps natifs ont ainsi été imprimés et immobilisés sur des feuilles de papier qui ont ensuite servide bandelettes. Leurs performances ont été évaluées en termes de limite de détection et se sont montrées comparables à celles de la nitrocellulose.Le troisième est une méthode de greffage de polymères sur membranes de cellulose. Contrairement aux précédents, ce procédé vise à augmenter lafonctionnalité des portions non-détectrices des dispositifs papier. Mais il peut aussi être utilisé comme une autre méthode de fonctionnalisation pourl’immobilisation covalente d’anticorps. Alors que le greffage de polymères sur cellulose se fait d’ordinaire par des procédures complexes et coûteuses,l’approche employée ici a été réalisée dans l’eau, à température ambiante, en une seule et courte étape. Des feuilles de cellulose ont ainsi été grefféesde divers polyacryliques, d’abord globalement par trempage puis localement par impression.Toutes ces stratégies peuvent aider à immobiliser de manière localisée des protéines sensibles sur des feuilles de cellulose. Plus généralement, ce sontde puissants outils pour facilement moduler les propriétés des surfaces de celluloses selon des motifs complexes, dans des conditions douces etbiocompatibles

Photolinker-free photoimmobilization of antibodies onto cellulose for the preparation of immunoassay membranes

International audiencePaper-based detection devices such as lateral flow immunoassays (LFIAs) are inexpensive, rapid, user-friendly and therefore highly promising for providing resource-limited settings with point-of-care diagnostics. Recently, this biosensing field has trended towards three-dimensional microfluidic devices and multiplexed assay platforms. However, many multiplexed paper-based biosensors implement methods incompatible with the conventional LFIA carrier material: nitrocellulose. It thus tends to be replaced by cellulose. This major material change implies to undertake a covalent immobilization of biomolecules onto cellulose which preserves their biological activity. In this perspective, the immobilization process elaborated in this study is entirely biocompatible. While antibody immobilization onto cellulose usually requires chemical modifications of either the biomolecule and/or the membrane, the light-based procedure presented here was performed without any chemical photolinker. Native biomolecules have been successfully immobilized onto paper sheets which therefore enable to perform LFIAs. More generally, the process expounded herein is fast, simple, cost-saving, environmentally-friendly and would be helpful to immobilize chemical-sensitive biomolecules onto cellulose sheets

Simple, Biocompatible and covalent antibody immobilization onto cellulose membranes for imunoassay

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Cotton-hydrogel composite for improved wound healing: Synthesize optimization and physicochemical characterization-part 1

Composite wound dressings gather the suitable properties of 2 or more polymeric materials. Thus, the present work aimed to assess the functionalization of cotton textiles with cyclodextrin‐hydroxypropyl methyl cellulose‐based hydrogel by chemical cross‐linking. The developed composites were evaluated based on their cross‐linking percentage and swelling ability and characterized by FTIR‐ATR, DSC, and TGA. The best conditions were achieved using 1‐step procedure, 0.54 mol L−1 of cross‐linking agent and 1:0.1 polymeric solution/textile (v/w). The textile physical structure was, also, a crucial parameter. From the substrates tested, nonwoven composites could accommodate more gel fraction with enhanced swelling. The functionalization of cotton fibers with cyclodextrin‐hydroxypropyl methyl cellulose‐based hydrogel improved cotton water uptake and surface properties, increasing its applicability as wound dressing.This article is a result of the project TSSiPRO—NORTE‐01‐0145‐FEDER‐000015—supported by the regional operational program NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund. The authors also acknowledge the Portuguese Foundation for Science and Technology (FCT) funding from the project UID/CTM/00264/2013 and FEDER funds through the COMPETE 2020—Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI‐01‐0145‐FEDER‐007136.info:eu-repo/semantics/publishedVersio