Protein-based nanobubble x-ray imaging method and agent
Inventors
Rose-Petruck, Christoph • Douglas, Trevor • Rand, Danielle • Uchida, Masaki
Assignees
Montana State University Bozeman • Brown University
Publication Number
US-10307527-B2
Publication Date
2019-06-04
Expiration Date
2035-04-21
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Abstract
Systems, compositions, methods and kits employ protein shells, such as ferritin or viral capsid shells, herein called nanobubbles, to enhance X-ray images of cells or body tissue under certain x-ray imaging methods. The nanobubbles have sub-micron size such as about 10 nm, about 40, 60, or 100 nm and may be functionalized for effective delivery to or uptake by a target tissue, in vivo or a cell culture. The nanobubbles are hollow, having a central core which may be empty or contain a fluid, such that the shells effectively form long-lived bubbles in the imaged environment, and are of low electron density and have different scattering properties than the surrounding tissue. X-ray imaging by spatial frequency heterodyne imaging enhances visualization or detection of tissue regions bearing the shells. The protein shells may be further treated to assure biocompatibility and/or to resist undesired interactions with non-targeted tissue, such as scavenging by the liver, or attack by the immune system. For example the nanobubbles may be filled with a hydrophobic gas such as perfluoropropane (octafluoropropane) to maintain their shape and resist hydrophilic interactions and delay the degradation of the protein shells. The nanobubbles may also be coated or treated by a surface-functionalization processes to effectively target specific tissues or tumor types, allow parenteral delivery, and/or deliver drugs or other agents to the imaged sites—so that when visualized by X-ray scatter imaging the presence of the nanobubbles indicates the existence and extent of the tumor or diseased tissue.
Core Innovation
The invention relates to systems, compositions, methods, and kits that utilize protein shells, such as ferritin or viral capsid protein shells, described as nanobubbles, to enhance X-ray images of cells or body tissue using specific x-ray imaging techniques. The nanobubbles are of sub-micron size, including approximately 10 nm, 40 nm, 60 nm, or 100 nm, and may be functionalized to improve delivery to or uptake by target tissue in vivo or in cell culture. The nanobubbles are hollow, having a central core that can be empty or contain a fluid, which forms stable, long-lived bubbles in the imaging environment. They are characterized by low electron density and different scattering properties than surrounding tissue.
The central problem being addressed is the enhancement of X-ray images, particularly overcoming limitations where only hard tissue yields high contrast in conventional absorption-based x-ray imaging, and soft tissue remains low in contrast. Existing contrast agents, such as gold nanoparticles, require high electron density to be effective, but these can present challenges in biocompatibility, toxicity, and removal from the body. The patent describes nanobubbles that provide contrast in spatial frequency heterodyne imaging (SFHI) X-ray techniques without requiring heavy metals or high electron density materials.
The core innovation demonstrates that protein-based nanobubbles, even those without metal or high-Z components, can be effectively visualized using X-ray scatter imaging methods such as spatial frequency heterodyne imaging. These nanobubbles can be tailored by filling with hydrophobic gases (e.g., perfluoropropane) to maintain structural integrity and delay degradation, as well as by surface modification to improve tissue targeting, delivery route options, and biocompatibility. By using SFHI, enhanced visualization or detection of tissue regions containing these nanobubbles is achieved, providing a biodegradable and essentially nontoxic agent suitable for parenteral administration that facilitates early diagnostic detection of target tissue features using available clinical X-ray equipment.
Claims Coverage
There are two independent claims: one directed to a method of imaging cells or tissue and one directed to a kit for imaging cells or a tissue. Several inventive features are covered in these claims.
Imaging with protein nanoparticles containing hydrophobic material via X-ray scatter and spatial frequency heterodyne image processing
This inventive feature comprises: - Providing to cells or tissue nanoparticles formed of protein, with an outer diameter under about 60 nm around a particle interior containing a hydrophobic material that prevents entry of aqueous material for stability in vivo. - The nanoparticles lack metal or other high-Z coating, component, or material that otherwise would increase x-ray transmission imaging contrast. - The method involves irradiating the sample with an X-ray source and performing X-ray scatter imaging with spatial frequency harmonic heterodyne image processing to effectively image regions of tissue or cells bearing the nanoparticles.
Kit comprising protein nanoshells filled with low electron density fluid for scatter X-ray imaging
This inventive feature includes: - A kit having a plurality of nanoparticles that bind to and/or are taken up by cells or tissue, where the nanoparticles comprise a protein nanoshell filled with a low electron density fluid. - The nanoparticles are operable as empty protein nanoparticles visible with enhanced contrast by scatter X-ray imaging, with imaging using spatial frequency harmonic heterodyne image processing to effectively image regions of tissue or cells bearing the nanoparticles. - The nanoparticles have an outer diameter under about 60 nm with a hydrophobic material trapped or residing in the interior that prevents entry of aqueous material and enhances stability in vivo, and the nanoparticles lack metal or other high-Z coating, component, or material.
The independent claims cover a method and a kit for imaging cells or tissue using protein-based nanoparticles (nanobubbles) that utilize a hydrophobic interior and lack metals, visualized via X-ray scatter with spatial frequency heterodyne image processing.
Stated Advantages
Protein nanobubbles are degradable and essentially nontoxic agents safe for parenteral or other administration.
Enables early diagnostic detection of target tissue features using commonly available clinical X-ray instrumentation.
Provides contrast in SFHI comparable to or better than gold nanoparticles of similar size, without requiring high electron density materials.
Biocompatible and biodegradable, offering improved clinical application due to ability to be broken down in the body.
The technique provides improved sensitivity and the ability to yield anisotropic information regarding scattering properties of tissue.
Allows enhanced sensitivity in soft tissue imaging, where conventional absorption-based X-ray imaging offers low contrast.
VLPs can be purified in large quantities relatively inexpensively, making them cost-effective alternatives to metal nanoparticle contrast agents.
Documented Applications
Enhancement of X-ray images of cells or body tissue for diagnostic imaging using scatter X-ray imaging with protein-based nanobubbles.
In vivo targeting and imaging of individual cells using nano-sized, protein-based contrast agents.
Imaging and detection of targeted cells, including but not limited to: cancerous, non-cancerous, epithelial, hematopoietic, stem, spleen, kidney, pancreas, prostate, liver, neuron, breast, glial, muscle, sperm, heart, lung, ocular, brain, bone marrow, fetal, blood, leukocyte, and lymphocyte.
Imaging tumors or cancer tissues, including melanoma, colon carcinoma, pancreatic, lymphoma, glioma, lung, esophagus, mammary, prostate, head, neck, ovarian, stomach, kidney, liver, and hepatocellular carcinoma.
Combining biomedical imaging function of the nanobubbles with targeting specific tissues or tumor types by surface-functionalization and delivery of drugs or other agents to imaged sites.
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