Tailored Nanoparticle Solutions for Sensing & Biosensing

Fluorescent Magnetic Nanoparticles

Arcana Nano Particle has fabricated magnetic-fluorescent composite particles, consisting of a magnetic core, silica spacer, and fluorescent quantum dots covalently bound to the silica surface. The quantum dots are functionalized to allow further coupling of biomolecules or other molecules.

A magnetic-fluorescent particle’s typical structure is depicted on the left, accompanied by a TEM image on the right.

Iron oxide nanoparticles, approximately 60 nm in diameter, were synthesized and enveloped in uniform silica shells. Quantum dots were then covalently attached, resulting in final particle dimensions of around 100 nm. Reaction parameters are adjustable to manipulate core size and shell thickness, while quantum dots with varying emission properties can be seamlessly integrated to yield samples with customized fluorescence characteristics.

Composite magnetic-fluorescent nanoparticles find utility across various domains, including multimodal imaging through optical and magnetic resonance imaging, fluorescence and magnetic-activated separation techniques, and the facilitation of highly sensitive lateral flow assays.

Gold Nanoshells with Magnetic and Plasmonic Properties

Gold nanoshells typically comprise a dielectric core, a silica layer, and an outer gold layer, offering distinctive and adjustable optical characteristics. This material holds promise for medical diagnostic assays and photothermal therapies. Fortis Life Sciences has developed magnetic-responsive variants by incorporating superparamagnetic nanoparticle cores coated with a silica spacer and a gold shell. Optical properties are modifiable by altering the particle size or gold shell diameter. Moreover, the gold surface serves as a valuable platform for biological molecule functionalization or customized surface modifications.

Displayed on the left is the standard structure of magnetic gold nanoshells, while the TEM image on the right showcases magnetic gold nanoshells manufactured by Arcana Nano Particle.

Highlighted Publications

• Mohammadi, M., Antoine, D., Vitt, M., Dickie, J. M., Sultana Jyoti, S., Wall, J. G., Johnson, P. A., & Wawrousek, K. E. (2022). A Rapid and Highly Sensitive SERS Immunoassay for Detecting SARS-CoV-2 in Saliva. Analytica Chimica Acta, 1229, 340290. DOI: 10.1016/j.aca.2022.340290.
• Huang, P.-J., Marks, H. L., Coté, G. L., & Kameoka, J. (2017). A Magneto-Fluidic Nanoparticle Trapping Platform for Surface-Enhanced Raman Spectroscopy. Biomicrofluidics, 11(3), 034116. DOI: 10.1063/1.4985071.
• Mukherjee, A., Darlington, T., Baldwin, R., Holz, C., Olson, S., Kulkarni, P., DeWeese, T. L., Getzenberg, R. H., Ivkov, R., & Lupold, S. E. (2014). Design and Evaluation of Antibody-Conjugated and Silica-Coated Iron Oxide Nanoparticles Targeting the Prostate-Specific Membrane Antigen. ChemMedChem, 9(7), 1356–1360. DOI: 10.1002/cmdc.201300594.

Utilizing nanoparticles in diagnostics entails careful consideration of various factors, including particle size, shape, metal composition, surface charge, and targeting ligands tailored to the specific diagnostic need. Our range of gold and silver nanoparticles offers diverse options of anionic and cationic capping ligands. Moreover, we specialize in customizing nanomaterials with precise functional groups, polymers, biomolecules, and inorganic coatings to meet targeting and compatibility requirements. In diagnostic settings, we often modify particles with additional detection elements like fluorophores or quantum dots, as well as biomolecules such as antibodies, antigens, and oligonucleotides to enhance detection sensitivity and specificity.

Within our standard product catalog, we offer various surface options optimized for surface modification and biofunctionalization. These surfaces serve as versatile starting platforms, accommodating both non-covalent and covalent bioconjugation approaches. For non-covalent strategies, we facilitate direct physisorption interactions between the biomolecule of interest and the metal particles. This interaction relies on electrostatic forces, hydrogen bonding, and van der Waals forces, ensuring efficient and stable binding.

Another non-covalent bioconjugation method involves direct chemisorption, where small linker molecules, such as thiols, disulfides, terminal carboxy, amino, or maleimide groups, are present on the nanoparticle surfaces. These functional groups facilitate interactions between the particles and biomolecules. Chemisorption offers increased stability and may necessitate chemical modification of either the antibody or the nanoparticles to ensure optimal binding.

It’s worth highlighting that while non-covalent strategies offer simplicity, they may result in weak and random attachment of biomolecules on the nanoparticle surface, leading to an unpredictable number of biomolecules bound per nanoparticle. An alternative approach involves covalent bioconjugation coupling strategies. For instance, this can be achieved through EDC/NHS coupling, where the nanoparticle surface contains a carboxyl group that can be activated using EDC/NHS chemistry. Subsequently, the amine-terminated biomolecule of interest is introduced to the activated nanoparticle. Any unreacted sites can then be blocked using an appropriate molecule to ensure specificity and stability of the conjugation.

The altered surface chemistry of nanoparticles, whether achieved through non-covalent or covalent methods, can undergo characterization using various assays including UV-Vis spectroscopy, dynamic light scattering (DLS), zeta potential analysis, Fourier-transform infrared spectroscopy (FTIR), and other analytical techniques.