Silica-coated bismuth sulfide nanorods as multimodal contrast agents for a non-invasive visualization of the gastrointestinal tract

Abstract

Non-invasive and real-time imaging of the gastrointestinal (GI) tract is particularly desirable for research and clinical studies of patients with symptoms arising from gastrointestinal diseases. Here, we designed and fabricated silica-coated bismuth sulfide nanorods (Bi2S3@SiO2 NRs) for a non-invasive spatial-temporally imaging of the GI tract. The Bi2S3 NRs were synthesized by a facile solvothermal method and then coated with a SiO2 layer to improve their biocompatibility and stability in the harsh environments of the GI tract, such as the stomach and the small intestine. Due to their strong X-ray- and near infrared-absorption abilities, we demonstrate that, following oral administration in mice, the Bi2S3@SiO2 NRs can be used as a dual-modal contrast agent for the real-time and non-invasive visualization of NRs distribution and the GI tract via both X-ray computed tomography (CT) and photoacoustic tomography (PAT) techniques. Importantly, integration of PAT with CT provides complementary information on anatomical details with high spatial resolution. In addition, we use Caenorhabditis Elegans (C. Elegans) as a simple model organism to investigate the biological response of Bi2S3@SiO2 NRs by oral administration. The results indicate that these NRs can pass through the GI tract of C. Elegans without inducing notable toxicological effects. The above results suggest that Bi2S3@SiO2 NRs pave an alternative way for the fabrication of multi-modal contrast agents which integrate CT and PAT modalities for a direct and non-invasive visualization of the GI tract with low toxicity.

Probing the modulated formation of gold nanoparticles–beta-lactoglobulin corona complexes and their applications

“…Similar phenomenon was seen with silica-coated Bi 2 S 3 nanorods 81 . Although our corona complexes showed appreciable stability at pH 2, digestive enzymes in stomach are likely to decompose the corona shell and change crystalline structures of AuNPs and different crystal faces lead to different X-ray attenuations 82 . Notably, stomach signals completely disappeared 24 h after administration.…”

Novel Bismuth‐Based Nanomaterials Used for Cancer Diagnosis and Therapy

“…Encouraged by the ideal NIR absorption property of Bi 2 S 3 NMs, Bi 2 S 3 nanorods (NRs) have been found to presentexcellent PA imaging capability for both tumor and gastrointestinal tract. [26,39] As shown in Figure 3A,t ween-20 coated Bi 2 S 3 Figure 3. (A) In vivo PA imaging and photoacoustic signal intensities in tumor sitesafter intravenous injectionwith tween-20 coated Bi 2 S 3 NRs at differentt ime points.Reprinted with permission from Ref.…”

“…As a narrow band gap semiconductor, Bi 2 S 3 NMs have been used as photosensitizers for sunlight‐triggered solar cells or photocatalysis due to the enhanced absorption in visible‐NIR region. Encouraged by the ideal NIR absorption property of Bi 2 S 3 NMs, Bi 2 S 3 nanorods (NRs) have been found to present excellent PA imaging capability for both tumor and gastrointestinal tract . As shown in Figure A, tween‐20 coated Bi 2 S 3 NRs were intravenously administered to tumor‐bearing mice, and the PA signals in the tumor site remarkably increased at 3 h post‐injection due to the enhanced permeability and retention (EPR) effect of NPs, and these signals could last up to 24 h. To improve the biocompatibility and stability in the harsh environments, Bi 2 S 3 NRs were coated with silica shells, and the resulting NRs were orally administrated to mice and could firstly travel to stomach within 10 min, then to the small intestine within 60 min.…”

Opportunities for new CT contrast agents to maximize the diagnostic potential of emerging spectral CT technologies

“…Similarly, MRI and CT can be used to visualize nanoparticles synthesized using bismuth surfactants in the precipitation of iron oxide[155]. Silica-coated bismuth sufide nanorods were shown to provide image contrast enhancement at CT imaging and also provide enhancement at photoacoustic tomography[156]. …”