Photoactive Branched and Linear Surface Architectures for Functional and Patterned Immobilization of Proteins and Cells onto Surfaces: A Comparative Study

Abstract

Molecular architecture affects the properties of surface layers. Photosensitive silanes with branched architectures allow patterning and coupling of proteins and cells on surfaces while maintaining their biofunctional state. Attachment can be directed to the activated regions of irradiated substrates with high selectivity (see image of mouse fibroblasts). Novel photosensitive silanes with a branched molecular architecture combining three end-functionalized oligoethylene glycol (OEG) and alkyl arms are presented. These molecules are synthesized and applied to the modification of silica surfaces. The resulting layers are tested in their ability for the selective, patterned and functional immobilization of proteins and cells. The results demonstrate and accurately quantify the benefits of branched OEG structures against linear analogues for preventing non-specific interactions with the biological material. Linear structures guarantee high selectivity for the attachment of proteins, however, they fail in the case of cells. Branched structures provide good antifouling properties in both cases and allow the formation of protein patterns with higher densities of the target protein, as well as cell patterns. The results demonstrate the careful balance between surface functionality, composition and architecture that is required for maximizing the performance of any surface-based assay in biology.

Light‐Triggered Multifunctionality at Surfaces Mediated by Photolabile Protecting Groups

“…A) Examples of caged silane coupling agents containing oligoethyleneglycol spacers specially designed to functional and specifi c coupling of proteins to surfaces. [ 78 ] B) Fluorescence image of patterns of biotin/Streptavidin/fl uorescently labelled biotin sandwich showing squares with different protein densities refl ecting different uncaging ratios of the underlying caged surface layer. [ 83 ] Irradiation time increases from "a" to "g".…”

Multi-photon patterning of photoactive o-nitrobenzyl ligands bound to gold surfaces

“…In this paper, we study such a film, a self-assembled monolayer (SAM) that uses thiol anchors to bind to metal surfaces, and contains the well-known photo-sensitive onitrobenzyl (oNB) group [10][11][12][13][14][15][16][17][18][19] that cleaves on photoactivation to release a specific chemical moiety, in our case a primary amine. SAMs containing this ligand have been studied in the past, although the bulk of the work has been done on SiO2 and similar surfaces, using silanes to bond to the surface, 10,14,16,17,[20][21][22][23] with a smaller number of papers concerned with thiolbound SAMs. 11,12,19,24 While oNB is the most heavily studied photocleavable protecting group, a number of other moieties with similar properties are also in use.…”

Optoregulated Biointerfaces to Trigger Cellular Responses

“…The real advantage of light activation for biological processes is the possibility to do experiments in situ, i.e., in the presence of cells and at defined time points, and to be able to follow the cellular response in real time, under the microscope. In situ activation of cellular processes using cyclo­[RGD­(DMNPB)­fK] is possible, without detectable signs of photodamage in the cells . Moreover, precise control of the onset of adhesive ligand activation also allows the indirect quantification of cell adhesion and the spreading of a cell population using a surface detection technique such as the quartz crystal microbalance (QCM) .…”

“…In situ activation of cellular processes using cyclo[RGD(DMNPB)fK] is possible, without detectable signs of photodamage in the cells. 57 Moreover, precise control of the onset of adhesive ligand activation also allows the indirect quantification of cell adhesion and the spreading of a cell population using a surface detection technique such as the quartz crystal microbalance (QCM). 63 QCM crystals modified with cyclo[RGD-(DMNPB)fK] allowed the monitoring of integrin binding events during early cell attachment of HUVECs (Figure 6a).…”