Patterning of Polypeptides on a Collagen-Terminated Tissue Surface

Abstract

Collagen is a ubiquitous component of the extracellular matrix environment, and numerous studies have been devoted toward the development of collagen-based tissue scaffolds. These efforts have been primarily focused on synthetic collagenous materials made from purified collagen. In this article, we present a preliminary study toward the development of a technique that can result in a tissue-derived collagen scaffold. The tissue-derived collagenous matrix was isolated from the retinal Bruch's membrane, and dip pen nanolithography was investigated as a mean to modify the collagenous surface. Characterization experiments of the collagenous surface indicate a fairly hydrophobic surface. Minimal swelling (<7%) of the collagen fibers was observed under elevated humidity conditions with negligible rearrangement of the surface. The hydrophobicity and roughness of the surface can pose a barrier for the deposition of molecules via scanning probe lithography. However, deposition of poly(glutamic acid) and polyarginine onto the surface could be achieved under high contact force and elevated relative humidity conditions (above 55%). Under these conditions, the deposition of the polypeptides occurred through molecular deposition with no observable molecular diffusion. On the other hand, the addition of 0.1% (v/v) Tween-20 surfactant to the inking solution facilitated diffusion of polypeptide inks by increasing the wettability of the collagenous surface. As such, deposition of molecule can be observed under lower contact force at ambient relative humidity (37−40%).

Dip‐pen nanolithography on SiOx and tissue‐derived substrates: comparison with multiple biological inks

“…The tissue substrate (inner collagenous zone of the BM) was prepared with slight variation to Sistiabudi and Ivanisevic (Sistiabudi and Ivanisevic 2007). Normal pigs eyes were obtained from the butchers post mortem.…”

“…As with previous studies this work was originally carried out on silicon oxide and was then repeated to the BM (Sistiabudi and Ivanisevic 2007). Ink solutions composed of CBP (GeneScript Corporation, Piscataway, NJ), fibronectin (Sigma, Milwaukee, WI), laminin (Sigma) and an ECM mixture were prepared as follows.…”

“…Recently our group showed that direct patterning could be performed on a biologically derived substrate with collagen-binding peptide (Sistiabudi and Ivanisevic 2008). Patterning to this substrate is a complex problem as the substrate is inherently heterogeneous (both chemically and physically), generally soft and hydrophobic after drying (Sistiabudi and Ivanisevic 2007). Thus far only peptides and collagen-binding peptide (CBP, biotin-CBP, or dansyl-CBP) have been patterned to a biologically derived substrate Ivanisevic 2007, 2008).…”

Dip‐Pen Nanolithography of Bioactive Peptides on Collagen‐Terminated Retinal Membrane

“…We have previously studied the conditions whereby deposition of long-chain polyamino acids may occur on the collagen-terminated surface of the inner collagenous layer of the Bruch's membrane (ICLBM). [9] As the native scaffold of the retinal pigment epithelial (RPE) cells in the retina, modification of this surface through deposition of bioactive molecules has been proposed as means to develop a scaffold for transplantation of RPE cells in treatment of age-related macular degeneration. [10,11] In another study, we have also shown that a sequence of amino acids (Cys-Gln-Asp-Ser-Glu-Thr-Arg-Thr-Phe-Tyr) may be used to anchor molecules onto the exposed collagen fibers on the ICLBM surface through solution incubation.…”

“…In order to achieve transport through molecular diffusion on the hydrophobic ICLBM surface, Tween-20 surfactant was added to the inking solution. [9,13] Figure 2B shows a three-dimensional layout of the ICLBM surface where a high degree of surface curvature is apparent. Roughness analysis performed from a series of height images of different samples resulted in an average root mean square (rms) value of 75 AE 26 nm.…”