Use of molecular beacons to image effects of titanium surface microstructure on beta 1 integrin expression in live osteoblast-like cells

• Type of Material: Article
• Authors: Frances E. Lennon, Georgia Institute of Technology; Christopher D. Hermann, Georgia Institute of Technology; Rene Olivares-Navarrete, Georgia Institute of Technology; Won Jong Rhee, Georgia Institute of Technology; Zvi Schwartz, Georgia Institute of Technology; Gang Bao, Emory University; Barbara Boyan, Emory University
• Language: English
• Date: 2010-10-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 Elsevier Ltd.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.biomaterials.2010.07.009
• Title of Journal or Parent Work: Biomaterials
• ISSN: 0142-9612
• Volume: 31
• Issue: 30
• Start Page: 7640
• End Page: 7647
• Grant/Funding Information: This work was supported by US PHS Grants AR052102, CA119338, and HL80711, as well as Children's Healthcare of Atlanta.
• Keywords: Materials Science, Biomaterials; Engineering, Biomedical; PROLIFERATION; Gene expression; Materials Science; Science & Technology; Integrin; Technology; IN-VIVO; Engineering; RNA; DIFFERENTIATION; Molecular imaging; DNA; Osteoblast; Titanium; LIVING CELLS; ALPHA(5)BETA(1); HYBRIDIZATION; 2'-O-METHYL; ROUGHNESS
• Research Categories: Engineering, Biomedical

Abstract

This study used molecular beacon technology to examine substrate-dependent changes in integrin subunit expression in living cells. Molecular beacons are oligonucleotide probes that can be delivered into live cells to allow for real-time imaging of mRNA. They have a stem-loop hairpin structure with a fluorophore-quencher pair, which opens when bound to the target mRNA sequence, resulting in a fluorescent signal upon excitation. A novel molecular beacon that is specific to the β1 integrin subunit mRNA was developed and used to image osteoblast-like MG63 cells in vitro on both glass and titanium surfaces of varying roughness. Specificity was verified by comparing the molecular beacon signal intensities to real-time PCR results in both wild-type cells and cells with shRNA knockdown of β1 integrin mRNA. The molecular beacon was able to detect changes due to both surface microtopography and silencing of the mRNA target. The results showed that effects of the substrate on β1 mRNA noted previously in confluent cultures were evident in pre-confluent cells as well, supporting the hypothesis that β1 integrin pairs are important in proliferation as well as differentiation of osteoblasts. This technique overcomes the limitations of traditional gene assays (PCR, immunofluorescence) by allowing for the real-time measurement and tracking of specific mRNAs in individual live cells prior to confluence.