Control over wettability via surface modification of porous gradients

Khung, Yit Lung; Cole, Martin A.; McInnes, Steven J. P.; Voelcker, Nicolas H.

doi:10.1117/12.759377

Cited by 14 publications

(11 citation statements)

References 44 publications

(72 reference statements)

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“…The contact angle measured for the 4-subunit OEG surface, 67°, is only slightly larger than values measured for 3-subunit, methoxy-terminated OEG layers formed on flat surfaces, which exhibit contact angles between 57-65° [40-42]. The nanotexture of the porous Si films may contribute to the observed contact angles; surfaces with high aspect ratio features such as those exhibited by porous Si have been found to display superhydrophobic properties [43, 44]. …”

Section: Resultsmentioning

confidence: 99%

The compatibility of hepatocytes with chemically modified porous silicon with reference to in vitro biosensors

et al. 2009

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Porous Si is a nanostructured material that is of interest for molecular and cell-based biosensing, drug delivery, and tissue engineering applications. Surface chemistry is an important factor determining the stability of porous Si in aqueous media, its affinity for various biomolecular species, and its compatibility with tissues. In this study, the attachment and viability of a primary cell type to porous Si samples containing various surface chemistries is reported, and the ability of the porous Si films to retain their optical reflectivity properties relevant to molecular biosensing is assessed. Four chemical species grafted to the porous Si surface are studied: silicon oxide (via ozone oxidation), dodecyl (via hydrosilylation with dodecene), undecanoic acid (via hydrosilylation with undecylenic acid), and oligo(ethylene) glycol (via hydrosilylation with undecylenic acid followed by an oligo(ethylene) glycol coupling reaction). Fourier Transform Infrared (FTIR) spectroscopy and contact angle measurements are used to characterize the surface. Adhesion and short-term viability of primary rat hepatocytes on these surfaces, with and without pre-adsorption of collagen type I, are assessed using vital dyes (calcein-AM and ethidium homodimer I). Cell viability on undecanoic acid-terminated porous Si, oxide-terminated porous Si, and oxide-terminated flat (non-porous) Si are monitored by quantification of albumin production over the course of 8 days. The stability of porous Si thin films after 8 days in cell culture is probed by measuring the optical interferometric reflectance spectra. Results show that hepatocytes adhere better to surfaces coated with collagen, and that chemical modification does not exert a deleterious effect on primary rat hepatocytes. The hydrosilylation chemistry greatly improves the stability of porous Si in contact with cultured primary cells while allowing cell coverage levels comparable to standard culture preparations on tissue culture polystyrene.

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Section: Resultsmentioning

confidence: 99%

The compatibility of hepatocytes with chemically modified porous silicon with reference to in vitro biosensors

et al. 2009

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“…The hydrophobic behavior of the functionalized groups could increase or decrease the wettability of the surface under different pore sizes conditions. Low wetting surfaces enable less contact between the surface and the solution and could be further investigate for better improvement of the quality of analysis by DESI-MS. 21 Further experiments will be done to investigate the surface wettability and to elucidate the mechanism responsible for the results obtained. The use of high speed imaging is also intended.…”

Section: Resultsmentioning

confidence: 99%

Functionalized Porous Silicon Surfaces as DESI-MS Substrates for Small Molecules Analysis

et al. 2014

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In desorption electrospray ionization mass spectrometry (DESI-MS), the type of surface in addition to low gas and solvent flow rates help to avoid the "splashing of solvent" or "washing effect", by which samples are promptly removed from the surface by the spray. These effects operate on smooth surfaces and generally result in unstable signals as the spray moves over the spot. The aim of this work is to compare the performance of functionalized porous silicon surfaces (pSi) for small molecules analysis with regard to the stability of the signal and the limits of detection (LODs) observed in DESI-MS. The results showed that functional groups, like 1-decene and heptadecafluoro-1,1,2,2-tetrahydrodecyl trimethoxysilane, on pSi surface provides a good alternative for dried spot analysis by DESI-MS, improving stability of the signal and the LODs. This improvement is possible because the dual process containing the weak sample-surface interactions of the hydrophobic characteristic of the functional groups and increasing the surface area of interaction between the sample and the thin solvent film created by the DESI spray, resulting in more effective dissolution of the analyte in the spray solvent without fast removal of the sample.

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“…For clarity, the presence of a hydrophobic poly(dimethylsiloxane) moiety in the present study created an inverse relationship between the porosity of the materials (surface roughness) and the hydrophilicity (wettability). Khung et al (2007) reported that surface silanisation with PEGS and APTES created hydrophilic surfaces which made it possible for the water droplets to penetrate the pores. In this way, the decrease in contact angles was observed from the large pores to the small pores, and the hydrophilicity increased.…”

Section: Morphological Physical and Hydrophobicity Propertiesmentioning

confidence: 99%

Role of polydimethylsiloxane in properties of ternary materials based on polyimides containing zeolite Y

et al. 2016

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Mixed matrix materials, containing poly(dimethylsiloxane), phosphine oxide-based polyimide, and zeolite Y were prepared by means of blending hybridisation. The thermal stability of the materials and the hydrophobic properties were enhanced. The decrease in the glass transition temperature of the materials with the increase in poly(dimethylsiloxane) content supported the polymer-chain flexibility. The pristine polyimide and the zeolite-filled polyimide exhibited the highest transparency. Fourier transform infrared (FTIR) spectroscopy confirmed that the increase in the amount of the lowest molecular mass poly(dimethylsiloxane) ingredient indicated strong alkyl and Si-O-Si stretching modes, whilst the alkyl and Si-O-Si stretching intensity decreased in the presence of the highest amount of and the highest molecular mass poly(dimethylsiloxane). The hydrophobic poly(dimethylsiloxane) moiety created an inverse relationship between the porosity of the materials (surface roughness) and the hydrophilicity. The nanocrystallite domain, identified by X-ray diffraction analysis (XRD) and possessing an exotherm crystallisation peak, occurred in the lowest amount of poly(dimethylsiloxane) with the highest molecular mass-based hybrid material. The nanocrystallite enhanced the storage modulus as determined by the dynamic mechanical analyser (DMA). The nanocrystalline formation resulted in a slight increase in the alkyl stretching and the Si-O-Si stretching of the lowest amount of and the highest molecular mass poly(dimethylsiloxane)-containing material over those of the lowest molecular mass poly(dimethylsiloxane) in the same amounts of material involved.

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Control over wettability via surface modification of porous gradients

Cited by 14 publications

References 44 publications

The compatibility of hepatocytes with chemically modified porous silicon with reference to in vitro biosensors

The compatibility of hepatocytes with chemically modified porous silicon with reference to in vitro biosensors

Functionalized Porous Silicon Surfaces as DESI-MS Substrates for Small Molecules Analysis

Role of polydimethylsiloxane in properties of ternary materials based on polyimides containing zeolite Y

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