DNA−Gold Nanoparticle Reversible Networks Grown on Cell Surface Marker Sites: Application in Diagnostics

Abstract

Effective identification of breast cancer stem cells (CSC) benefits from a multiplexed approach to detect cell surface markers that can distinguish this subpopulation, which can invade and proliferate at sites of metastasis. We present a new approach for dual-mode sensing based on targeting using pointer and signal enhancement using enhancer particle networks for detection by surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS). We demonstrate our concept to detect cell surface markers, CD44 and CD24, in three breast cancer cell lines to identify a CD44+/CD24- subpopulation of CSCs. The designed network structure can be well-controlled and has improved sensitivity compared to conventional approaches with ability to detect a single target on the membrane of a living cell. We have also developed a fractal approach to model the dimension of the network structure and developed an empirical relationship to estimate the number of particles in the network and its size. The empirical equation was validated with experiments and finite-difference time-domain simulations, and the cell phenotyping results were found to be in good agreement with published data from conventional sorting by flow cytometry.

Single-cell screening and quantification of transcripts in cancer tissues by second-harmonic generation microscopy

“…Recently, Raman and plasmonic approaches are proposed utilizing the strengths of Raman or dark-field microscopy for cellular imaging. [14][15][16] However, the scattering from cellular components is much higher than the signal from individual Raman or plasmonic probes since the scattering cross section is proportional to the volume squared, 17 eliminating the possibility of tissue analysis due to low signal-to-noise ratio (SNR) using these techniques.…”

Single-Cell Quantification of Cytosine Modifications by Hyperspectral Dark-Field Imaging

“…18, 19 Owing to the dipole resonance from the interaction with incident photons, the large scattering cross-section of metal NPs can generate a ten- to million-fold stronger signal than conventional fluorophores, 20, 21 providing a high SNR without laser excitation. Besides, the LSPR spectrum can be fine-tuned, dependent on the NP size, shape, material, and surrounding environment.…”

Growth graphene on silver–copper nanoparticles by chemical vapor deposition for high-performance surface-enhanced Raman scattering

“…Surface-enhanced Raman scattering (SERS) as one of the most powerful probing tools for biochemical applications has received increasing attention [1][2][3]. To date, the most widely studied SERS platforms are solution-phase Ag, Au and Cu nanoparticles, as enormous Raman enhancement factors could be obtained in areas of "hot spots" from the dispersed nanoscale systems [4].…”