SERS Nanoprobes

SERS nanoprobes for intracellular applications

A wide variety of gold nanoparticle-based probes can be designed for the application in living eukaryotic cells. Based on their function and the SERS spectra they transmit, intracellular SERS probes can be divided into different types: probes consisting of nanoparticles (A), (labeled) hybrid probes (B), and probes with pH-dependent SERS siganture (C).

Hybrid probes for NIR-SERS sensing and multiplexing

SERS offers numerous opportunites in the study of spectral changes during molecular interactions in complex biosystems. In order to observe such interactions, so called Raman reporter molecules can be introduced, which can, e.g., serve as indicators of binding events or as pH sensors. In addition, utilization of such Raman reporters enables the identification of different SERS probes in multiplex approaches.

We design, characterize, and apply SERS hybrid probes and targeting vectors for bioanalytical applications. The nanoprobes are surrounded by a biopolymer coating, which serves as a scaffold for the covalent and/or hydrophobic linkage of various Raman reporters and targeting units. Stabilization of our functionalized NP/NA plays a role in case of designing biocompatible probes for in vitro studies in eukaryotic cells. Since nanoaggregates of Au and Ag nanoparticles have emerged as efficient SERS substrates, the role of the coating is elucidated regarding aggregation of AgNP, stabilization of AuNP, and partitioning of analyte molecules.

Matschulat, A.; Drescher, D.; Kneipp, J., Surface-Enhanced Raman Scattering Hybrid Nanoprobe Multiplexing and Imaging in Biological Systems. ACS Nano 2010, 4, 3259-3269 Abstract

Kneipp, J.; Kneipp, H.; Wittig, B.; Kneipp, K., Following the Dynamics of pH in Endosomes of Live Cells with SERS Nanosensors. Journal of Physical Chemistry C 2010, 114, 7421-7426 Abstract

SERS and normal Raman on nanoparticle-influenced cellular systems: NANOTOX

In recent years, a broad discussion about the advantages and disadvantages of nanoparticles has begun. Due to their extraordinary properties, nanoparticles with different characteristics have found multiple applications in various fields of today’s life, such as pharmaceuticals and cosmetics, materials science, optics and catalysis. With their omnipresence, the investigation of toxicological issues of nanoparticles on living organisms arises. We design and apply SERS nanoprobes for studies of the properties of nanomaterials in biological systems and their potential nanotoxicity at the molecular level.

In order to determine optimum analysis parameters, to develop a test based on Raman spectroscopy, and also to evaluate the influence of intracellular SERS nanoprobes on the cellular systems, we investigate their physicochemical properties and cytotoxicity in different cell lines using also standard methods.

Kneipp, J.; Kneipp, H.; McLaughlin, M.; Brown, D.; Kneipp, K., In vivo molecular probing of cellular compartments with gold nanoparticles and nanoaggregates. Nano Letters 2006, 6, (10), 2225-2231 Abstract

Drescher, D.; Orts-Gil, G.; Laube, G.; Natte, K.; Veh, R. W.; Österle W.; Kneipp, J., Toxicity of amorphous silica nanoparticles on eukaryotic cell model is determined by particle agglomeration and serum protein adsorption effects. Anal. Bioanal. Chem. 2011, 400, 1367-1373 Abstract