Biochips Fabrication and Surface Characterization

In this chapter, synthesized copolymer compositions are processed in order to fabricate coated biochips by using spin-coating technique. Developed biochips have subsequently been used in sandwich ELISA experiment via three different techniques: physical i

  • PDF / 825,614 Bytes
  • 15 Pages / 439.37 x 666.142 pts Page_size
  • 42 Downloads / 256 Views

DOWNLOAD

REPORT


Biochips Fabrication and Surface Characterization

Abstract In this chapter, synthesized copolymer compositions are processed in order to fabricate coated biochips by using spin-coating technique. Developed biochips have subsequently been used in sandwich ELISA experiment via three different techniques: physical immobilization; covalent immobilization; and immobilization through amine-bearing spacers. In this chapter, principles behind each of the mentioned methods are described in a great detail. The major emphasis of the chapter is on the characterization of the developed biochips. In that path, morphology and topography of the coated platforms have thoroughly been investigated. Moreover, wettability of the polymer coated chips before and after treatment with different techniques were also investigated. Proposed platforms from both categories of treated and untreated, then, were analyzed by XPS analysis to study surface chemistry of the fabricated bioreceptors. This chapter has also discussed the correlation of obtained data from each characterization technique to another in a very comprehensive manner.





Keywords Physical immobilization Covalent immobilization Amine-bearing spacers Morphology analysis Topography analysis Surface chemistry



3.1





Synthesis of Poly(MMA-co-MAA) Compositions

Four different compositions of poly(MMA-co-MAA) were synthesized via free-radical polymerization as shown in Table 2.1. Polymerization reaction was conducted in tetrahydrofuran (THF) as a solvent and by using azobisisobutyronitrile (AIBN) as an initiator. A detailed description of polymer synthesis can be found in our previous publications [1–4]. It is expected to have increasing concentration of –COOH groups as the concentration of MAA monomer in the polymerization reaction increases.

© The Author(s) 2016 S. Hosseini and F. Ibrahim, Novel Polymeric Biochips for Enhanced Detection of Infectious Diseases, SpringerBriefs in Forensic and Medical Bioinformatics, DOI 10.1007/978-981-10-0107-9_3

23

24

3 Biochips Fabrication and Surface Characterization

Fig. 3.1 Spin-coating technique for production of the polymer coated biochips [3]

3.2

Fabrication of Spin-Coated Biochips

Silicon wafers were used as substrates to produce a fine layer a polymer coated biochips by using spin-coating system (Fig. 3.1). Polymer solutions of different copolymer compositions (5 % solution) were prepared by dissolving polymers in THF. A careful washing process is required prior to the spin-coating, which is explained in a great detail in our previous published works [2]. Variety of spin-coating parameters have been examined until the optimized method was determined [4]. One step coating with the duration of 55 s and the spinning rate of 3000 rpm was performed by Laurell, WS-650MZ-23NPP spin coater. The average thickness of the coated layer was *10 µm. Since ELISA procedure includes many steps with long incubation times, the firmness of the developed coatings draws a great deal of importance. Polymer coated silicon biochips have shown sig

Data Loading...