This work demonstrates the ability to electrospin reagents into water-soluble nanofibers resulting in a stable on-chip enzyme storage format. Polyvinylpyrrolidone (PVP) nanofibers were spun with incorporation of the enzyme horseradish peroxidase (HRP). Scanning electron microscopy (SEM) of the spun nanofibers was used to confirm the non-woven structure which had an average diameter of 155 ± 34 nm. The HRP containing fibers were tested for their change in activity following electrospinning and during storage. A colorimetric assay was used to characterize the activity of HRP by reaction with the nanofiber mats in a microtiter plate and monitoring the change in absorption over time. Immediately following electrospinning, the activity peak for the HRP decreased by approximately 20%. After a storage study over 280 days, 40% of the activity remained. In addition to activity, the fibers were observed to solubilize in the microfluidic chamber. The chromogenic 3,3′,5,5′-tetramethylbenzidine solution reacted immediately with the fibers as they passed through a microfluidic channel. The ability to store enzymes and other reagents on-chip in a rapidly dispersible format could reduce the assay steps required of an operator to perform.
References
[1]
Haeberle, S.; Zengerle, R. Microfluidic platforms for lab-on-a-chip applications RID B-2451-2012. Lab on a Chip？2007, 7, 1094–1110, doi:10.1039/b706364b.
[2]
Nugen, S.R.; Asiello, P.J.; Connelly, J.T.; Baeumner, A.J. PMMA biosensor for nucleic acids with integrated mixer and electrochemical detection. Biosens. Bioelectron.？2009, 24, 2428–2433, doi:10.1016/j.bios.2008.12.025.
[3]
Zhou, P.; Young, L.; Chen, Z. Weak solvent based chip lamination and characterization of on-chip valve and pump. Biomed. Microdevices？2010, 12, 821–832, doi:10.1007/s10544-010-9436-z.
[4]
Reneker, D.; Smith, D. Naonfiber Structures for Supporting Biological Materials. WO/2006/133118; PCT/US2006/021785, 2006. Available online: http://patentscope.wipo.int/search/en/WO2006133118 (accessed on 15 August 2012).
[5]
Andrady, A. Science and Technology of Polymer Nanofibers; Wiley-Interscience: Hoboken, NJ, USA, 2008.
[6]
Wang, Z.; Wan, L.; Liu, Z.; Huang, X.; Xu, Z. Enzyme immobilization on electrospun polymer nanofibers: An overview RID A-7659-2010 RID A-5635-2008. J. Molecul. Catal. B Enzym.？2009, 56, 189–195, doi:10.1016/j.molcatb.2008.05.005.
[7]
Gorji, M.; Jeddi, A.A.A.; Gharehaghaji, A.A. Fabrication and characterization of polyurethane electrospun nanofiber membranes for protective clothing applications. J. Appl. Polym. Sci.？2012, 125, 4135–4141, doi:10.1002/app.36611.
[8]
Kanafchian, M.; Valizadeh, M.; Haghi, A.K. Fabrication of nanostructured and multicompartmental fabrics based on electrospun nanofibers. Korean J. Chem. Eng.？2011, 28, 763–769, doi:10.1007/s11814-010-0449-3.
[9]
Feng, C.; Khulbe, K.C.; Matsuura, I.; Gopal, R.; Kaur, S.; Rarnakrishna, S.; Khayet, A. Production of drinking water from saline water by air-gap membrane distillation using polyvinylidene fluoride nanofiber membrane. J. Membr. Sci.？2008, 311, 1–6, doi:10.1016/j.memsci.2007.12.026.
[10]
Prince, J.A.; Singh, G.; Rana, D.; Matsuura, T.; Anbharasi, V.; Shanmugasundaram, T.S. Preparation and characterization of highly hydrophobic poly(vinylidene fluoride)—Clay nanocomposite nanofiber membranes (PVDF-clay NNMs) for desalination using direct contact membrane distillation. J. Membr. Sci.？2012, 397, 80–86, doi:10.1016/j.memsci.2012.01.012.
[11]
Gouma, P. Electrospun Enzyme-Nanocompositebiosensing Material. U.S. Patent 2006/0134716 A1, June 2006.
[12]
Stasiak, M.; Studer, A.; Greiner, A.; Wendorff, J.H. Polymer fibers as carriers for homogeneous catalysts. Chem. Eur. J.？2007, 13, 6150–6156, doi:10.1002/chem.200601555.
[13]
Luu, Y.; Kim, K.; Hsiao, B.; Chu, B.; Hadjiargyrou, M. Development of a nanostructured DNA delivery scaffold via electrospinning of PLGA and PLA-PEG block copolymers. J. Control. Release？2003, 89, 341–353, doi:10.1016/S0168-3659(03)00097-X.
[14]
Huang, X.; Ge, D.; Xu, Z. Preparation and characterization of stable chitosan nanofibrous membrane for lipase immobilization RID A-2073-2010 RID B-1462-2009. Eur. Polym. J.？2007, 43, 3710–3718, doi:10.1016/j.eurpolymj.2007.06.010.
[15]
Yu, D.-G.; Nie, W.; Zhu, L.M.; Branford-White, C. Fast dissolution nanofiber membrane of ferulic acid prepared using electrospinning. In Proceedings of 2010 4th International Conference on Bioinformatics and Biomedical Engineering (iCBBE), Chengdu, China, 18-20 June 2010; pp. 1–4.
[16]
Haaf, F.; Sanner, A.; Straub, F. Polymers of N-Vinylpyrrolidone—Synthesis, Characterization and Uses. Polym. J.？1985, 17, 143–152, doi:10.1295/polymj.17.143.
[17]
Salalha, W.; Kuhn, J.; Dror, Y.; Zussman, E. Encapsulation of bacteria and viruses in electrospunnanofibres. Nanotechnology？2006, 17, 4675–4681, doi:10.1088/0957-4484/17/18/025.
[18]
Volpe, G.; Compagnone, D.; Draisci, R.; Palleschi, G. 3,3',5,5'-tetramethylbenzidine as electrochemical substrate for horseradish peroxidase based enzyme immunoassays. A comparative study. Analyst？1998, 123, 1303–1307, doi:10.1039/a800255j.
[19]
Nugen, S.R.; Asiello, P.J.; Baeumner, A.J. Design and fabrication of a microfluidic device for near-single cell mRNA isolation using a copper hot embossing master. Microsyst. Technol.？2008, 15, 477–483.
