Photoacoustic imaging (PAI) is an emerging modality in biomedical imaging. Photoacoustic effect is the basis for PAI, where a photoacoustic contrast agent absorbs optical pulses to initiate localized heating and rapid thermal expansion, thus generating thermoelastic stress waves. Therefore, ideal PAI dyes should have strong NIR light absorbance and high light-heat conversion efficiency. However, most current low molecular weight organic PAI contrast agents are fluorescent dyes, where the light-heat conversion efficiency is dramatically impaired due to the energy loss by fluorescence emission. Herein, we report a series of highly efficient photoacoustic dyes with COOH, NH2 and NHS ester functionalities, from an inexpensive industrial computer-to-plate NIR absorber (IR830 p-toluenesulfonate) that has a strong NIR absorbance but an extremely low fluorescence emission. In vitro and in vivo studies show that the functional IR830 dyes have low cytotoxicity, and are 2.1 folds brighter in photoacoustic imaging than traditional photoacoustic dye indocyanine green (ICG). The Lowest Limit of Quantification of the IR830 series dyes is as low as the 1/7 of that of ICG. These indicate that the functional IR830 dyes have great potential as highly efficient photoacoustic dyes.
Photoacoustic imaging (PAI) is an emerging modality in biomedical imaging. Ideal PAI dyes should have strong NIR absorbance and high light-heat conversion efficiency. However, most current low molecular weight organic PAI contrast agents are fluorescent dyes, where the light-heat conversion efficiency is dramatically impaired due to the energy loss by fluorescence emission. Herein we report a series of highly efficient functional photoacoustic dyes from an inexpensive industrial computer-to-plate NIR absorber (IR830) that has a strong NIR absorbance but an extremely low fluorescence emission. The functional IR830 dyes show low cytotoxicity, much brighter in photoacoustic imaging than traditional photoacoustic dye indocyanine green. These indicate that the functional IR830 dyes have great potential as highly efficient photoacoustic dyes.
Gold nanoparticles have seen unprecedented development in the biomedical field, particularly for cancer therapy. They have received extensive attention because of their easy preparation, functionalization, biocompatibility, non-cytotoxicity, and detectability. Functionalized gold nanoparticles can be applied in the fields of drug and gene delivery, photothermal therapy, and bioimaging. This review introduces methods for preparing various shapes of gold nanoparticles and describes their current applications in the field of cancer treatment. Moreover, the review presents the development routes and current issues of gold nanoparticles in clinical theranostics.
A new family of multiblock copolymers (PEA-b-AP) based on poly(ester amide) (PEA) and aniline pentamer (AP) with the unique properties of being both electroactive and biodegradable was synthesized via a two-stage active solution polycondensation. The new synthesis approach proceeded smoothly, and avoided the complicated purification steps for separating the intermediate products. The molecular weight of PEA blocks was regulated by varying the nucleophilic/electrophilic monomers feed ratios. The chemical structures of the copolymers were confirmed by both IR and NMR spectra. UV-Vis spectroscopy indicated that the copolymers possessed of the intrinsic electroactivity of AP blocks, and showed three reversible oxidation states. The copolymers had lower degradation rates than the PEA homopolymers with similar molecular weight, and their degradation rates were greatly affected by the proportion of AP blocks. In vitro cell culture studies of the PEA-b-APs revealed that they facilitated the proliferation of RSC96 Schwann cells and displayed a good biocompatibility. These biodegradable copolymers with electroactive function may have great potential for use as nerve repair and regeneration scaffold materials in tissue engineering. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4722–4731
