Technological development of intracellular polysilicon–chromium–gold chips for orthogonal chemical functionalization

Abstract

Increasingly, advances in microtechnologies are focused on obtaining new chips intended for applications in fields such as nanomedicine and cell biology, taking advantage of the ability of microelectronics to manufacture devices with cell dimensions and a large variety of features. Here, we report a technology for the fabrication of multi-material chips, using polysilicon and gold as device layers, to be used as bi-functional cellinternalizable devices. In our case, one of the main technological challenges is to overcome the low adherence between these two materials, especially because of their small contact-area, only 9 µm 2. Thus, in order to circumvent this difficulty a chromium adherent-layer was deposited in between. After fabrication, the devices following this design can be successfully internalized inside living macrophages without affecting their viability. The advantage of having multiple material layers in one device is the potential to render multi-tasking chips, as once they are appropriately functionalized, we can provide the chip the ability of being bi-functional. Hence, and as a proof of concept, two different proteins, Wheat Germ Agglutinin (WGA) and Concanavalin (ConA), were 3 immobilized on the chip surface through self-assembled monolayers using orthogonal chemistry. The results of this work show a well-controlled fabrication, the bi-functional capabilities and no cell-toxicity of intracellular polysilicon-chromium-gold chips. These devices have a promising future as intracellular functional platforms for biosensing, drug delivery and diagnosis.

Nanostructured materials for photodynamic therapy: synthesis, characterization and in vitro activity

“…The microparticles (mP) used in this study were prepared as described elsewhere; 48 and consist of a layer of polysilicon and a layer of gold attached by a thin chromium layer. Three different samples were prepared: a control sample containing MTMS and MHEG (PEG-mP), a sample with MTMS and ATPP-LA (ATPP-LA-mP), and a sample with MTMS and ZnATPP-LA (ZnATPP-LA-mP).…”

“…S18 † for microfabrication details). 48 Fig. 2 shows the SEM images of the NR and the microparticles, prior to functionalization, depicting their shape, dimensions and surface composition.…”

“…For the immobilization of the porphyrins in the mP, because these particles have two surfaces, each of a different material, they must be functionalized in a sequential manner as described elsewhere 48 (see Fig. 6a).…”

“…(3) Hexahedral Janus microparticles (mP) with two different materials (gold and polysilicon) to allow orthogonal functionalization, and that recently have been reported to be biocompatible and internalized by SK-BR-3 and MCF-10A cell lines. 48,49 The gold surface present in all the vehicles allows the immobilization of the disulde-bearing amidoporphyrins. Therefore we describe the synthesis and characterization of two new amidoderivatives of an aminophenylporphyrin and its Zn analogue using lipoic acid (LA) as linker, their conjugation to the three above-mentioned gold-based vehicles, the physicochemical characterization of the porphyrin-loaded vehicles through different techniques, and their PDT activity, in terms of the singlet oxygen production, as well as their photocytotoxicity and cellular uptake using HeLa cells, in order to select the optimal delivery vehicle for use in PDT.…”

Reversible Immobilization of Proteins in Sensors and Solid‐State Nanopores

“…This suggests that a residue of EDTA is retained on the gold surface even after thiol‐OEG deposition. Binding of APTES to gold has previously been reported,[22b,26] and it might be that this also entails the retention of EDTA. We found that the surfaces exposed to orthogonal functionalization also showed good retention of their activity during repeated use over the course of at least 1 month (Figure S5, Supporting Information).…”