An active DNA-based nanoprobe for photoacoustic pH imaging

Abstract

A DNA-based nanoprobe sensitive to pH has been developed for pH photoacoustics imaging through a ratiometric approach.

DNA-based nanocarriers to enhance the optoacoustic contrast of tumorsin vivo

“…[34] Namely, NC6 and NC8 were assembled by heating to 85° for 5 min, cooling down from 85 to 65°C in 20 steps (1°C per step, 5 min each step) and cooling down from 65 to 25°C in 80 steps (0.5°C per step, 12 min each step). NC2 was assembled under the following protocol: [31,32] Optical absorbance and fluorescence measurements: Absorbance and fluorescence properties of the NCs were measured at 34°C. To compare the potential quenching effect of the NCQ+ versus NCQ-, the measurements were performed at matching IRDye 800CW concentration in PBS.…”

“…The OT response of the NCs at depths relevant for further in vivo studies was initially evaluated using tissue mimicking phantoms. Samples were encapsulated into agar-based tissue mimicking phantoms with defined optical properties (scattering coefficient of 5cm -1 and absorption coefficient of 0.05cm -1 at 700 nm) as previously described [31,32] (see Experimental Section).…”

“…[22][23][24][25][26][27] In the context of in vivo cancer imaging, DNA-NCs have been loaded with a variety of contrast agents for different modalities, including dyes for fluorescence imaging, [28] radioisotopes for SPECT [29] and PET, [30] as well as gold nanoparticles for OT. [23] Based on the knowledge that distance-dependent quenching of small molecule NIR dyes yields significant enhancement of OT signals, [31,32] we hypothesized that DNA-NCs could be used to construct biodegradable OT contrast agents with high optoacoustic signal generation and tumor uptake properties. Using precise positioning of IRDye 800CW [33] fluorophore molecules at very close proximities within DNA nanostructures, we obtained a substantial OA signal enhancement and tailored the effective size of these nanostructures to offer prolonged blood clearance times compared to the free dyes, thereby enhancing tumor uptake.…”

DNA‐Based Nanocarriers to Enhance the Optoacoustic Contrast of Tumors In Vivo

“…The OT response of the NCs at depths relevant for further in vivo studies was initially evaluated using tissue mimicking phantoms. Samples were encapsulated into agar-based tissue mimicking phantoms with defined optical properties (scattering coefficient of 5 cm −1 and absorption coefficient of 0.05 cm −1 at 700 nm) as previously described [39,40] (see Experimental Section). The OT spectra of NCQ− and NCQ+ structures (Figure 3a for NC6 and Figure S3c, Supporting Information, for NC2) showed the expected signal peaks in accordance with the measured absorbance ( Figure 2a for NC6 and Figure S3a, Supporting Information, for NC2).…”

“…[30][31][32][33][34][35] In the context of in vivo cancer imaging, DNA-NCs have been loaded with a variety of contrast agents for different modalities, including dyes for fluorescence imaging, [36] radioisotopes for SPECT [37] and PET, [38] as well as gold nanoparticles for OT. [31] Based on previous reports on the relation between fluorescence quenching and enhancement of OT signals, [13,[39][40][41][42][43][44] we hypothesized that DNA-NCs could be used to construct biodegradable OT contrast agents with high optoacoustic signal generation and tumor uptake properties. Using precise positioning of IRDye 800CW [14] fluorophore molecules at very close proximities within DNA nanostructures, we obtained fluorescent quenching of the dyes with substantial OA signal enhancement and tailored the effective size of these nanostructures to offer prolonged blood clearance times compared to the free dyes, thereby enhancing tumor uptake.…”