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Title: (Use a capital letter at the start of the title only)
Nanofibrous polymer layers for biological sensing
Authors & affiliations:
a
Macagnano A.a*, Zampetti E.a, Pantalei S.a, Taddei A.R. b, De Cesare F.c
IMM-CNR, Rome, Italy; b CIME- University of Tuscia,Viterbo (Italy); c DABAC-University
of Tuscia, Viterbo (Italy)
Abstract: (Your abstract must use Normal style and must fit in this box. Your abstract should
be no longer than 300 words. The box will ‘expand’ over 2 pages as you add text/diagrams into it.)
One of the potentially interesting techniques for increasing the sensitivity of sensors is to
create a 3-dimensional nanofibrous structure, since a pattern of this kind would increase
the surface exposed to interactions with molecules and then the density of potential
binding sites for target analytes. Theoretically, this arrangement could increase
sensitivity, whilst maintaining selectivity, and capture efficiency. The generation of
nanofibrous matrices with biological properties would permit the development of novel
bio-mimetic materials [1]. In this context, the creation of DNA-based biosensors, which
use nanofibrous frameworks linked with oligonucleotides, might be particularly promising
in several applications (health, environment, foodstuff). To achieve this target, two waterinsoluble polymers (polymethylmethacrylate - PMMA - and 1.8 % carboxylated
polyvinylchloride - PVC-COOH) were used to create nanofibrous scaffold structures by
electrospinning technique [2]. In electrospinning high static voltages are used to produce
membrane-like webs of fibres (20-1000 nm), with approximately one to two orders of
magnitude surface areas higher than those of flat layers. The scaffold frameworks were
properly designed and implemented in order to cover transducers as quartz
microbalances and interdigitated electrodes and then to create proper sensors. Two
crosslinking chemistries were studied for functionalization in situ of both polymers with
amines, specifically by using 1,5-pentane diamine [3,4]. Both ssDNA and dsDNA
(single-strand and double-strand DNA, respectively) immobilizations (PO4-5’-30bp mers)
on the implemented nanostructured scaffolds were obtained through immersion of both
kinds of transducers covered alternatively with both nanofibrous layers, in a solution
consisting of EDAC (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride)
solved in N-methylimidazole buffer (Fig.1).
Fig.1. Experimental design for creation of DNA-based
biosensor founded on a QCM coated with a fibrous polymer
layer functionalized with amines
All steps of the process (i.e. polymer deposition, diamine and then oligonucleotides
covalent immobilizations on quartz microbalance platform) were investigated (Fig.2) by
a
b
Fig.2. Photographs of PMMA layer taken by: a) Stereo
Microscope (10x) outfitted with a digital imaging pick-up; b)
SEM JEOL 5200 (2000 x; 25 kV high tension)
image (SEM, AFM, TEM), colorimetric and gravimetric analyses.
Preliminary results are reported and their bio-sensing potentialities discussed.
Keywords: polymeric nanofibres, electrospinning, DNA, QCM
References:
1] Macagnano A., Zampetti, E., Pistillo B.R., Bearzotti A., Pantalei S., d’Agostino R.,
Double layer sensor reproducing perception dynamics of olfactory cells, Advances in
Science and Technology, 58 (2008) 91-96
2] Zhou X.C., Huang L.Q., Li S.F.Y., Microgravimetric DNA sensor based on quartz
crystal microbalance: comparison of oligonucleotide immobilization methods and
application in genetic diagnosis, Biosensors and Bioelectronics, 16 (2001), 85-95
3] Fixe F., Dufva M., Telleman P., Christensen C.B.V., Functionalization of
poly(methylmethacrilate) (PMMA) as a substrate for DNA microarrays, Nucleic Acid
Research, 32 (2004) 1 e9, 1-8
4] Goddard J.M., Hotchkiss J.H., Polymer surface modification for the attachment of
bioactive compounds, Progress in Polymer Science 32 (2007) 698-725
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