Atomic force measurements of 16-mercaptohexadecanoic acid and its salt with CH3, OH, and CONHCH3 functionalized self-assembled monolayers

Morales-Cruz, Ángel L.; Tremont, Rolando; Martinez, Ramon A.; Romañach, Rodolfo J.; Cabrera, Carlos R.

doi:10.1016/j.apsusc.2004.07.058

Cited by 27 publications

(27 citation statements)

References 29 publications

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“…The adhesion force in Fig. 7 is of the order of nano-Newton, which is similar to MoralesCruz's result [31], and so it is in agreement with the actual value. When the chain length varies from 1 nm to 2.5 nm, the adhesion force shows a sharp drop, and in the range of 2.5-3.5 nm the adhesion force is not sensitive to changes in chain length.…”

Section: Resultssupporting

confidence: 79%

Effect of chain length of self-assembled monolayers on adhesion force measurement by AFM

Guo¹,

Zhao²

2006

Journal of Adhesion Science and Technology

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Abstract-It has been confirmed experimentally that the adhesion force measured between an atomic force microscope (AFM) tip and the self-assembled monolayers (SAMs) has a direct correlation with the chain length of SAMs, and that the adhesion force decreases with the increase of the chain length. In this paper, a theoretical model is put forward to calculate the adhesion force between the AFM tip and the SAMs by integrating the Lennard-Jones potential. The theoretical results are in good agreement with the existing experimental results.

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Section: Resultssupporting

confidence: 79%

Effect of chain length of self-assembled monolayers on adhesion force measurement by AFM

Guo¹,

Zhao²

2006

Journal of Adhesion Science and Technology

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“…Analytical techniques, including FTIR and AFM, have shown the existence of monolayers and morphorgy of the surface modifications (Ulman 1996;Smith et al 2004;Chidsey and Loiacono 1990;Yam et al 2001;Liao et al 2005;Morales-Cruz et al 2005). Because PDL and PLL are optical isomers, the FTIR results of PLL are good candidates for assigning the specific bondings during PDL immobilizations (Yam et al 2001).…”

Section: Discussionmentioning

confidence: 96%

“…Among common approaches, Fourier transform infrared spectroscopy (FTIR) provides the optical approach for examining functional groups and molecular orientation (Liao et al 2005;Ulman 1996;Smith et al 2004;Chidsey and Loiacono 1990;Yam et al 2001). In addition, an atomic force microscope (AFM) was used to assess layer thickness and molecular packing in microscale (Smith et al 2004;Morales-Cruz et al 2005). …”

Section: Analytical Techniques For Surface-modified Meamentioning

confidence: 99%

Characterization of surface modification on microelectrode arrays for in vitro cell culture

Lin¹,

Chen²,

Liao³

et al. 2007

Biomed Microdevices

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This study aims to investigate surface-modified microelectrodes on the microelectrode arrays (MEAs) for neuronal interfaces with in vitro cell culture. The polyimide (PI) MEA was fabricated by using micro-electro-mechanical systems (MEMS) techniques. Self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA) were utilized to modify the microelectrode surface of the MEA. The SAMs' modified surface of microelectrodes offered a reliable interface to immobilize biological ligands through covalent bonding. To increase biocompatibility, the poly-D-lysine (PDL) was immobilized on the SAMs' modified microelectrodes. Several analytical techniques were used to define the physical structure and functional groups of surface-modified gold microelectrodes on the MEA. Spectra of the Fourier transform infrared reflection (FTIR) were applied to characterize the molecular structure of MUA-SAMs and PDL on the microelectrodes. The spectra, two peaks of amide I (at 1,613 cm(-1)) and amide II (at 1,548 cm(-1)), revealed that covalent amide bonding existed in PDL-MUA-SAMs modified surfaces. The thickness and formation of the MUA and PDL were also observed and quantified by using an atomic force microscope (AFM). The impedance measurement of PDL-MUA-SAMs modified MEA only increased slightly to an average of 524.6 +/- 55.8 kOmega from 352.9 +/- 34.4 kOmega of bare gold microelectrode (p < 0.05, N = 20). In addition, the time-course changes of total impedance resulting from cell sealing resistance and gap reactance were recorded for 7 days for inferring the growth of cell lines on the electrode contact of modified MEA. The experiment of 3T3 fibroblasts, PC12 cells, primary glial cells, and primary cortical neurons cultured on the modified MEAs displayed a good adhesion rate. These biocompatibility assays demonstrated that the neuronal cells are able to grow in a proximity to PDL-MUA-SAMs modified microelectrodes of the MEAs for effective electrophysiological stimulation/sensing schemes and for future implantation purposes.

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“…The successful deposition of alkanethiol SAMs requires the gold substrates to be freshly cleaned by, for example, annealing in a hydrogen-oxygen flame [6], or by exposure to UV/ozone [7][8][9][10][11], or by treatment with a cleaning solution [12][13][14][15][16][17]. For the deposition of a monolayer, the cleaned substrate is immersed in an ethanolic solution of the thiol, rinsed (ethanol), dried (nitrogen) and used immediately [5].…”

Section: Introductionmentioning

confidence: 99%

Self-assembled structures of alkanethiols on gold-coated cantilever tips and substrates for atomic force microscopy: Molecular organisation and conditions for reproducible deposition

Lamprou

Smith

Nevell

et al. 2010

Applied Surface Science

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Atomic force measurements of 16-mercaptohexadecanoic acid and its salt with CH3, OH, and CONHCH3 functionalized self-assembled monolayers

Cited by 27 publications

References 29 publications

Effect of chain length of self-assembled monolayers on adhesion force measurement by AFM

Effect of chain length of self-assembled monolayers on adhesion force measurement by AFM

Characterization of surface modification on microelectrode arrays for in vitro cell culture

Self-assembled structures of alkanethiols on gold-coated cantilever tips and substrates for atomic force microscopy: Molecular organisation and conditions for reproducible deposition

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