Study On Controllable Fabrication Of Fiber Probes Based On The Interface Nature

Significant attention is focused on the optics application in the studies of alive cell for its smaller injury on cell and credible result. To achieve the optic detection in individual cell, it is prerequisite for optical detector to be tiny volume, highly optical collection- efficiency, low noise and light background. As the biosensor of optic transfer and measurement, suitable profile of fiber probe is essential for improvement of optical collection- efficiency.Pencil-like fiber probes with controllable profile were prepared by the choice of coverlayers and etching time at etchant /coverlaye. Diffusion theory was applied in explaining the effect of diffusion on the size and profile of probe. Ag-coating-probe with aperture at its apex has been obtained by means of (3-mercaptopropy) trimethoxysilane (HSC₃H₆Si(OCH₃)₃,3-MPT) SAMs assembled on fiber probe surface and chemical plating silver under ultrasonic condition. Considering the shorter hold time due to oxidation of silver coating and cytocompatibility of probe, 3-MPT and 1-octadecanethiol (C₁₈H₃₇SH) were used to construct the Self- Assembled Mixed Monolayers (SAMM) and moreover, co-polymers composed of N-vinylcarbazole(VCz)and Methyl methacrylate(MMA)were deposited on 3-MPT SAMs or SAMM to form inert multilayer polymer films—Complex Self-Assembled Films (CSAF) on silver. 3-MPT SAMs can also be formed on fiber surface by means of hydrolyzed Si(OCH₃)₃ group on hydroxyl- SiO2, which prevents the apex of tips from the deposition of co-polymer. The thickness of co-polymer can be controlled by augment or diminishment of -Si(OH)3 on Ag to some extent. The dissertation is composed by following chapters:1. Effect of the Interface Properties on Profile of Fiber Probes: In this chapter, the profiles and their changes of pencil-like fiber tips in static chemical etching process had been studied with several coverlayer-etchant systematically. Octane, paraxylene, oleic acid and n-xylene were chosen as coverlayer according to their natures such as surface tension, solubility, molecular volume and polarities. The interface tensions of coverlayer /HF aqueous solution were then calculated by Fu-Ju-Fu Method because the interface tensions of coverlayer /HF aqueous solution is different from that of air /HF aqueous solution, and the cone heights of the probes were also calculated with the interface tension. Compare to the calculation value and experiment value about cone length, whether added surfactant or not, we found that the solubility of HF aqueous in different organic phases and diffusion in two phases play a very important role in tip's profile. It has been concluded that Diffusion is another important factor working on the profile of probes.2. Preparation of Silvering Probe with Silver Aperture at the Top of Probe: Considering the cytocompatibility and bonding ability with some groups of compounds, metal silver, in this chapter, was used as the coating material of probe. In order to avoid the light leakage and meet the need of individual cell detection, probes with silver coating and aperture at the top were fabricated with the help of chemical plating and ultrasonic. According to the yield of silvering probe with aperture at the top and the size of aperture, we filtered better process out in different techniques. The probes prepared in this way have higher luminous flux and the leaking of light was also solved preferably.3. SA Studies on Silvering Probe Surface (I)—Control and Quantitative Measurement of Two Molecules in SAMM on silver: Considering the oxidation and cytocompatibility of silver coating probe, it is necessary for some appropriate modification on silvering probe surface. In this chapter, SAMM consisted of 3-MPT and C₁₈H₃₇SH was fabricated by means of exchange and competitive absorption on Ag at given concentrations...