Targeted gold nanorod contrast agent for prostate cancer detection by photoacoustic imaging

Abstract

A targeted gold nanoparticle has been developed as a contrast agent for photoacoustic medical imaging. We have studied cancer cell targeting by antibody conjugated gold nanorods for high contrast photoacoustic imaging. By changing the aspect ratio of the elongated "rod" shape of the gold nanoparticle, its plasmon peak absorption wavelength can be tuned to the near IR ͑700-900 nm͒ for an increased penetration depth into biological tissue. Effective cell targeting and sensitive photoacoustic detection of a single layer of cells are demonstrated. Combining ultrasound with contrast agent based photoacoustic imaging is proposed as a visual tool to compound molecular and structural information for early stage prostate cancer detection.

Surface Plasmon Resonance of Nanoparticles and Applications in Imaging

“…When a plasmonic resonance occurs, the term λ ε = ε c +ε m 2(ε c −ε m ) can have a real part that is lower than 1 2 , and become close to an eigenvalue of the operator K * B . Let d σ be the minimum of the distances of λ ε and λ μ to the spectrum σ (K * B ).…”

“…Let D 1 and D 2 be two smooth bounded domains such that the distance dist(D 1 , D 2 ) between D 1 and D 2 is positive. Let ν (1) and ν (2) …”

Applications of gold nanorods in biomedical imaging and related fields

“…Later, they used antibody-conjugated GNRs for in vivo breast cancer PAT imaging [45]. Agarwal et al [46] demonstrated the ability of PAT for early detection of prostate cancer. Chen et al [47] found that silica coatings on GNRs can increase the signal to noise ratio of PAT compared with uncoated GNRs.…”

Cancer cell sensing and therapy using affinity tag-conjugated gold nanorods

“…The in vivo PAI of human prostate cancer is achieved by antibody-conjugated AuNRs [32]. In this study, antibody-conjugated AuNRs are designed to have an absorption band in the range of 700 -840 nm to be optimal in vivo applications and a single layer of cells is monitored by PAI.…”

“…The colour of the nanoparticles also changes depending on the absorption maxima variations. This tuneability of the optical absorption facilitates various biomedical applications including, but not limited to, colorimetric detection assays for proteins [15][16][17][18], DNAs [18][19][20][21] and cancer cells [22] that operate in the visible range; photothermal therapy [23][24][25][26][27][28], photoacoustic imaging (PAI) [29][30][31][32][33][34] and heat-induced drug delivery [35] that operate in the NIR range.…”