RESUMO
Herein, we have designed composite SERS-active micro-satellites, which exhibit a dual role: (i) effective probes for determining cellular composition and (ii) optically movable and easily detectable markers. The satellites were synthesized by the layer-by-layer assisted decoration of silica microparticles with metal (gold or silver) nanoparticles and astralen in order to ensure satellite SERS-based microenvironment probing and satellite recognition, respectively. A combination of optical tweezers and Raman spectroscopy can be used to navigate the satellites to a certain cellular compartment and probe the intracellular composition following cellular uptake. In the future, this developed approach may serve as a tool for single cell analysis with nanometer precision due to the multilayer surface design, focusing on both extracellular and intracellular studies.
Assuntos
Fibroblastos/citologia , Pinças Ópticas , Dióxido de Silício/química , Análise de Célula Única/instrumentação , Análise Espectral Raman/instrumentação , Animais , Linhagem Celular , Desenho de Equipamento , Ouro/química , Nanopartículas Metálicas/química , Camundongos , Prata/químicaRESUMO
Surface-enhanced Raman scattering (SERS) microspectroscopy is a very promising label-free, noncontact, and nondestructive method for real-time monitoring of extracellular matrix (ECM) development and cell integration in scaffolds for tissue engineering. Here, we prepare a new type of micrometer-sized SERS substrate, core-shell microparticles composed of solid carbonate core coated with silver nanoparticles and polyhedral multishell fullerene-like structure, astralen. Astralen has been assembled with polyallylamine hydrochloride (PAH) by the layer-by-layer manner followed by Ag nanoparticle formation by means of a silver mirror reaction, giving the final structure of composite particles CaCO3(PAH/astralen)x/Ag, where x = 1-3. The components of the microparticle carry multiple functionalities: (i) an easy identification by Raman imaging (photostable astralen) and (ii) SERS due to a rough surface of Ag nanoparticles. A combination of Ag and astralen nanoparticles provides an enhancement of astralen Raman signal by more than 1 order of magnitude. Raman signals of commonly used scaffold components such as polylactide and polyvinyl alcohol as well as ECM component (hyaluronic acid) are significantly enhanced. Thus, we demonstrate that new mechanically robust and easily detectable (by astralen signal or optically) core-shell microspheres based on biocompatible CaCO3 can be used as SERS platform. Particle design opens many future perspectives for fabrication of SERS platforms with multiple functions for biomedical applications, for example, for theranostic.
Assuntos
Carbonato de Cálcio/química , Fulerenos/química , Nanopartículas Metálicas/química , Poliaminas/química , Prata/química , Análise Espectral Raman/métodos , Ácido Hialurônico/química , Microesferas , Imagem Molecular/métodos , Tamanho da Partícula , Poliésteres/química , Álcool de Polivinil/química , Propriedades de SuperfícieRESUMO
The problems of layer-by-layer-based surface enhancement Raman scattering (SERS)-sensor application for pharmaceutical analysis were discussed. Layer-by-layer (LbL) method allows fabrication of encapsulated SERS platforms with high reproducibility of enhancement factor and increased signal/noise ratio of Raman scattering. LbL encapsulation approach opens an avenue to implement a novel type of theranostic systems combining SERS based sensing and drug delivery in one entity. The area of encapsulation development toward smart multifunctional theranostic systems could bring benefits for personalized medicine and should minimize costs and resources at preclinical and clinical study in pharmacology while testing new bioactive compounds.