Micropatterned Reactive Nanofibers: Facile Fabrication of a Versatile Biofunctionalizable Interface

Abstract

Electrospinning with subsequent photopatterning of copolymers containing thiol-reactive maleimide groups was utilized to fabricate micropatterned nanofiber arrays amenable for biomolecular immobilization and detection. Bead-free uniform nanofibers were obtained by electrospinning of copolymers composed of poly­(ethylene glycol) methacrylate, methyl methacrylate, and maleimide based monomers. While the poly­(ethylene glycol) based monomer provides necessary hydrophilicity to impart the fibers with antibiofouling properties, the methyl methacrylate component improves fiber formation. The maleimide functional group in the polymers serves a dual role of inducing photochemical cross-linking as well as enabling efficient functionalization of nanofibers using the thiol–maleimide coupling reaction. The maleimide based fiber cross-linking also enables fabrication of micropatterned arrays using photolithography. Obtained nanofiber based micropatterns undergo facile functionalization with thiol-containing dyes, protein binding ligands, and dye-labeled oligonucleotides. Hybridization studies on the oligonucleotide immobilized arrays with fluorescently labeled complementary sequence demonstrated that sensing on this platform was achievable with high specificity. Thus, efficient bioconjugation as well as detection of bioanalytes such as proteins and oligonucleotides can be undertaken on these nanofibers arrays. The strategy to obtain nanofiber based micropatterns disclosed here provides an access to a versatile interface adaptable for biomedical applications.

Inhibitory effect of nucleotides on acetylcholine esterase activity and its microflow-based actuation in blood plasma

“…5,6 These facts prompted us to fabricate a self-powered lab-on-achip (LOC) device using the principle of an ''enzyme micropump'' as mentioned above but by immobilizing blood plasma in a polymer based thin film made by the layer-by-layer (LbL) assembly approach. 7 Here we have measured the flow velocity generated from acetylcholine esterase (AChE) present in blood plasma by adding its substrate (acetylcholine and acetylthiocholine). We also checked the effect on the flow velocity due to the presence of different adenosine-based nucleotides, cyclic adenosine monophosphate to adenosine mono/di/triphosphate (abbreviated as cAMP, AMP, ADP, ATP), and compared the results with those in aqueous buffer-based pure enzyme immobilized ideal flow producing conditions (Fig.…”

Hydrogels and Their Role in Biosensing Applications

“…This review aims to investigate, how hydrogels contribute to improving these parameters. [23] (PEG methacrylate) Dye, protein, Oligonucleotide Fluorescence Covalent, Diels-Alder cycloaddition [50,51] Chitosan Enzymes Chromogenic (indigo) Covalent, amide bond [54] Chitosan, dextran Glucose Electrochemical Electrostatic [76] Responsive Hydrogels Acrylic acid and dimethylaminoethyl methacrylate Urea Piezoresistive pressure sensor Encapsulation [90] Shape-memory DNA film pH, Ag + /cysteine Photonic crystal Hybridization [93] Poly(methyl methacrylate-co-methacrylic acid)…”

“…The microporous structure of the nanofibers provided a high surface area with good accessibility, making them an ideal coating for biosensing applications. [51] Using hydrogels as the coating material also has the benefit of providing additional functionality within the network, such as directly immobilizing a chromogen, which only becomes visible for readout upon presence of the target. Nam et al used hydrogel superimposed glass fiber membrane strips for the colorimetric detection of nitrite ions.…”

Shaping Macromolecules for Sensing Applications—From Polymer Hydrogels to Foldamers

“…Considering the wide range of characteristics that can be achieved by tuning in both molecular and structural levels and the ability to respond to external stimuli, such as temperature [ 58 , 65 ], light [ 66 ], pH [ 58 , 94 ], ionic strength [ 62 , 127 , 135 ], and the presence of (bio)molecules [ 104 , 136 , 137 , 138 , 139 ], synthetic hydrogels have become important materials for the design and construction of sensors and biosensors in various fields of applications. Different types of synthetic polymer-based hydrogels have been used in sensing, e.g., poly(acrylic acid) [ 40 , 105 , 140 ], poly(ethylene glycol) [ 36 , 39 , 141 , 142 ], poly(ethylene glycol) methacrylate [ 143 ], poly(acrylic acid- co -dimethylaminoethyl methacrylate) [ 144 ], poly(methyl methacrylate- co -methacrylic acid) [ 145 ], polyacrylamide [ 35 , 37 , 77 , 103 ], poly(acrylamide- co -acrylic acid) [ 146 ], poly(N,N-dimethylacrylamide) [ 78 ], poly(N,N-dimethylacrylamide- co -2-(dimethylmaleimido)N-ethyl-acrylamide- co -vinyl-4,4-dimethylazlactone) [ 102 , 106 ], poly(N-isopropylacrylamide- co -2-acrylamido-2-methylpropane sulfonic acid) [ 147 ], poly(vinyl alcohol) [ 81 ], poly(2-hydroxyethyl methacrylate) [ 75 ], and poly(diallyldimethyl ammonium chloride) [ 75 ]. Polymer materials are functionalized with fluorophores, chromophores, or conducting elements to enable readout using relevant detection techniques ( Table 2 ).…”