US 20080255460 A1
Various compositions, methods, and devices are provided that use fluorescent nanoparticles to function as markers, indicators, and/or light sources. In an exemplary embodiment, the fluorescent nanoparticles are biocompatible, and more preferably they can be formed from a fluorophore core surrounded by a biocompatible shell, such as a silica shell. In one aspect, the fluorescent nanoparticles can be delivered to tissue to mark the tissue, enable identification and location of the tissue, and/or illuminate an area surrounding the tissue.
1. A method for locating, marking, or illuminating tissue, comprising:
delivering at least one biocompatible fluorescent nanoparticle to tissue;
delivering energy to the at least one fluorescent nanoparticle to cause the at least one fluorescent nanoparticle to fluoresce; and
collecting light fluoresced from the at least one fluorescent nanoparticle.
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This application claims priority to U.S. Provisional Patent Application No. 60/911,546 filed on Apr. 13, 2007 and entitled “Fluorescent Nanoparticle Compositions, Methods, and Devices,” which is hereby incorporated by reference in its entirety.
The present invention relates to fluorescent nanoparticles, and in particular to various compositions, methods, and devices that use fluorescent nanoparticles.
Illuminating light incident on tissue is transmitted through, scattered by, absorbed, or reflected by that tissue. At certain wavelengths, after absorbing the illuminating light, tissue can re-emit light energy at a different wavelength (autofluorescence). If a substance is introduced into the tissue or is present between tissue layers, or in lumens, it can fluoresce after absorbing incident light as well. Detecting devices can be placed in relationship to the tissue to image light that is transmitted, scattered, reflected, or fluoresced from the tissue. It is well known in the art that certain wavelengths of light tend to be preferentially absorbed, reflected, or transmitted through different types of tissue. Generally, near infrared light (600-1300 nm) tends to coincide with minima in the spectral absorption curve of tissue, and thus allows the deepest penetration and transmission of light. For optical analysis of surface structures or diagnosis of diseases very close to the body surface or body cavity surfaces or lumens, UV light and visible light below 600 nm can also be used, as it tends to be absorbed or reflected near the surface of the tissue.
Various modalities are currently used for imaging of tissue and organs, including visible light endoscopes, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET). Many anatomical spaces and tissues, however, are not easily accessible and viewable. Moreover, the use of imaging equipment can be expensive and time consuming, and their application is often limited.
Various contrast agents are also employed to effect image enhancement in a variety of fields of diagnostic imaging, the most important of these being X-ray, magnetic resonance imaging (MRI), ultrasound imaging, and nuclear medicine. Additionally, optical labels, such as fluorescent dyes, are introduced into tissue samples to signal abnormal biological and/or chemical conditions of tissues of a living subject. Despite many successful applications, conventional optical labels have many drawbacks. For example, conventional optical labels are generally toxic to living cells and tissues comprised of living cells. Additionally, conventional optical labels such as fluorescent dyes generally suffer from short-lived fluorescence because the dyes undergo photo bleaching after minutes of exposure to an excitation light source. This renders them unsuitable for optical imaging that requires extended time period of monitoring. Moreover, conventional optical labels are sensitive to environmental changes such as pH and oxygen concentration. Another drawback of conventional optical labels is that typically the excitation spectra of such labels are quite narrow, while the emission spectra of such labels is relatively broad, resulting in overlapping emission spectra. Thus, when a combination of conventional optical labels with different emission spectra are used in optical imaging, multiple filters are need to detect the resultant emission spectra of the combination. Additionally, fluorescent labels are generally inefficient at converting the excitation light to the emission wavelength, and the resulting signal can be very weak.
Accordingly, there remains a need for improved compositions, methods, and devices for use in medical imagining, and more particularly for marking, indicating, and illuminating tissue.
The present invention generally provides various compositions, methods, and devices for using fluorescent nanoparticles as markers, indicators, and/or light sources. In one embodiment, an endoscopic adaptor for viewing fluorescent nanoparticles is provided and includes first and second members removably matable to one another, e.g., using threads or other mating elements, and adapted to engage a portion of an endoscope eyepiece therebetween. The first member can have a viewing lumen formed therethrough and adapted to axially align with a viewing lumen formed in an endoscope eyepiece, and a cavity formed therein for seating a filter adapted to filter light received through the viewing lumen of the first member. The device can also include a filter disposed within the cavity in the first member. In an exemplary embodiment, the filter is adapted to transmit light in the fluorescent waveband. For example, the filter can be an interferometric long-pass filter.
The components of the adaptor can have a variety of configurations. In one embodiment, the second member can be in the form of a ring having a lumen extending therethrough with an enlarged diameter portion adapted to receive an enlarged diameter portion formed on an endoscopic eyepiece. The second member can also optionally include first and second hemi-cylindrical halves that are hingedly mated to one another to allow the second member to be positioned around an endoscopic eyepiece. In an another embodiment, the device can include a filter cartridge removably disposed within the first member and adapted to retain a filter therein. For example, the first member can include a slot formed therein and extending across the viewing lumen for receiving the filter cartridge such that a filter containing in the filter cartridge is disposed across the viewing lumen.
In yet another embodiment, an endoscopic system is provided and includes an endoscope eyepiece having a viewing lumen formed therethrough between proximal and distal ends thereof, and an adaptor adapted to removably mate to the endoscope eyepiece and adapted to retain a filter therein such that the filter is in alignment with the viewing lumen formed in the endoscope eyepiece to thereby filter light through the viewing lumen. The adaptor can include a viewing lumen extending therethrough and adapted to be aligned with the viewing lumen in the endoscope eyepiece when the adaptor is mated to the endoscope eyepiece. In an exemplary embodiment, the adaptor can be an eyepiece extension member having the viewing lumen formed therein, and a mating element adapted to mate to the eyepiece extension to engage a portion of the endoscope eyepiece therebetween. A filter can optionally be removably or fixedly disposed within the adaptor. In an exemplary embodiment, the filter is adapted to transmit light in the fluorescent waveband. In other aspects the adaptor can include a filter cartridge removably disposed therein and adapted to retain a filter therein.
Exemplary methods for viewing fluorescent nanoparticles are also provided, and in one embodiment the method can include coupling an adaptor to a proximal end of an endoscope, inserting a distal end of the endoscope into a body lumen to position the distal end in the direction of tissue containing at least one fluorescent nanoparticle, and activating a light transmitting element to emit fluorescent light onto the at least one fluorescent nanoparticle such that reflected fluorescent light is transmitted through a filter contained within the adaptor and is received by an image obtaining element coupled to the endoscope. The light transmitting element can extend through the endoscope to emit fluorescent light onto the at least one fluorescent nanoparticle, and the filter can be configured to block visible light.
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.
The present invention generally provides various compositions, methods, and devices for using fluorescent nanoparticles in various medical applications. In certain exemplary embodiment, the fluorescent nanoparticles can be used to mark, indicate, and/or illuminate an object, such as a device or tissue. The particular configuration of the fluorescent nanoparticles can vary, but preferably the nanoparticles are biocompatible and non-toxic. The shape, size, and morphology of the nanoparticles can vary. In an exemplary embodiment, as shown in
The particular materials used to form the core and the shell can vary depending on the intended use, but in an exemplary embodiment the core includes organic dye molecules and the shell is silica-based. Fluorescing dyes are available at various wavelengths, including both visible and non-visible wavelengths. Dyes having any wavelength can be used with the present invention, but the particular dye selected may depend on the intended use. For example, where the dye needs to be viewed through tissue, the dye preferably has a wavelength that is near or within the infrared range, i.e., from about 600 nm to 1350 nm. Particular dyes in the near infrared wavelength are preferred as they demonstrate the best transmissibility for passing through tissue. In an exemplary embodiment, the nanoparticles contain a dye that has an absorption and emission cross-section in the region of about 800 nm. Exemplary dyes are Cy 5.5 manufactured by GE Healthcare and Indocyanine Green manufactured by Acros Organics N.V. In order to view dyes with an emission cross-section outside of the visible spectrum for medical applications, energy must be delivered to the dye to excite the molecules and the resulting emission by the molecules must be collected by specialized equipment sensitive to this non-visible waveband. Various exemplary methods and devices for delivering energy to dyes with emission cross-sections outside of the visible spectrum will be discussed in more detail below. Where the dye does not need to be viewed through tissue, or is viewed through very thin tissue, the dye can have a wavelength that is within the visible range, i.e., from about 400 nm to 700 nm. When used in the body, light may need to be delivered to the tissue containing the particles to enable viewing. The light source may be external to the body for delivering light internally, or an internal light source may be used for internal application.
A person skilled in the art will appreciate the fluorescent nanoparticles can be formed from a variety of materials using various methods. Exemplary fluorescent nanoparticles and methods for making the same are disclosed in detail in U.S. Publication No. 2004/0101822 of Wiesner et al. entitled “Fluorescent Silica-Based Nanoparticles,” U.S. Publication No. 20046/0183246 of Wiesner et al. entitled “Fluorescent Silica-Based Nanoparticles,” and U.S. Publication No. 2006/0245971 of Burns et al. entitled “Photoluminescent Silica-Based Sensors and Methods of Use,” which are hereby incorporated by reference in their entireties. A person skilled in the art will also appreciate that fluorescent semiconductor nanocrystals, also referred to as quantum dots, can also be used with the various methods and devices disclosed herein.
As indicated above, the present invention provides various compositions, methods, and devices that use fluorescent nanoparticles. In one embodiment, fluorescent nanoparticles can be used to locate, mark, or illuminate tissue. For example, one or more nanoparticles can be delivered into or onto tissue, including various body cavities. The nanoparticle(s) can illuminate an area surrounding the tissue when energy is delivered thereto, or they can enable the tissue containing the particles to be located. The nanoparticles can also be used to mark the tissue, thus enabling future identification and location of the tissue. A person skilled in the art will appreciate that the particular tissue or body lumen to be located, marked, or illuminated, as well as the technique for delivering the nanoparticles to the tissue, can vary and the following techniques are merely exemplary.
In one embodiment the nanoparticles can be used to locate a structure that traverses through other tissue or is otherwise visually inaccessible. Many tubular structures, such as the ureter, are not completely visually accessible, but rather traverse through other tissue and thus are difficult to locate and/or view. Various regions of the colon can also be difficult at times to access visually. A solution containing one or more fluorescent nanoparticles can thus be delivered to the structure of interest to enable a surgeon to locate the structure. The method of delivery can vary. For example, the fluorescent nanoparticles can be disposed in a liquid, foam, or gel solution, such as a saline solution, and they can be delivered, for example, using an intravenous (IV) drip or by direct injection into the tissue. Where the solution has a low viscosity, the structure can be isolated, e.g., clamped off or otherwise closed, to contain a finite volume of particles therein, or an open line, such as a saline drip, can be continuously fed to the structure. Alternatively, the solution can be modified to have a high viscosity and/or to contain adhesives. Exemplary solutions will be discussed in more detail below. Once the solutions is delivered to the structure, energy can be applied to the area to excite the nanoparticle(s), thereby enabling the precise location of the particle(s), and thus the structure containing the particle(s), to be determined.
In yet another embodiment, the nanoparticles can have a property that enables them to be filtered into a desired structure, such as the ureter or colon. In particular, delivery to the kidney will enable filtration into the ureter, and delivery to the liver will enable filtration into the colon. For delivery to the ureter via the kidney, the particles typically have a size in the range of about 4 nm to 11 nm, whereas the particles typically have a size that is greater than about 12 nm for delivery to the colon via the liver. Various delivery techniques can be used, including those previously discussed, such as IV delivery into the patient's circulatory system. Once delivered into the body and filtered into the structure to be located, e.g., the ureter or colon, energy can be delivered to the vicinity to excite the particle(s), thereby enabling the precise location of the particle(s), and thus the structure containing the particle(s), to be determined.
In yet another embodiment, the nanoparticles can be used to identify the spread of cancerous cells. With certain types of cancer, such as breast cancer, the nanoparticles can be injected into the tumor. The nanoparticles will be carried into other parts of the body by way of the blood or lymphatic vessels or membranous surfaces. Energy can thus be delivered to the body to locate the nanoparticles and thereby identify whether the tumor has spread. This is particularly useful in determining whether cancerous cells have reached the sentinel lymph node. The use of nanoparticles formed from a fluorophore center core and a biocompatible shell is also advantageous as it provides a non-toxic method for locating cancerous cells, unlike prior art methods which utilize radio-isotopes and semi-conductive nanoparticles which contain toxic metals.
A person skilled in the art will appreciate that the aforementioned techniques can be used to locate any structure. By way of non-limiting example, other exemplary structures include the structures in the biliary system, the lymphatic system, and the circulatory system.
The present invention also provides methods for marking tissue. In one embodiment, the nanoparticles, or a solution containing one or more nanoparticles, can be applied or “painted” onto a tissue surface, or injected into tissue. The applied nanoparticles can function as a marking used to allow for subsequent identification of the tissue. For example, during a colonoscopy the nanoparticles can be applied to or near a polyp that cannot be removed during the procedure. During a subsequent procedure, the nanoparticles can be excited with energy and used to locate and identify the polyp, for example from the abdominal perspective. The markings can also be used to indicate orientation. For example, directional markings, such as arrows or other lines, can be made with the nanoparticles. Various applicators, such as a paint brush or similar applicator, can be used, and an exemplary applicator will be discussed in more detail below. In another embodiment, the markings can be used to detect leaks, for example in a closed system fluid based implant, such as with gastric bands. One failure mode experienced with gastric band is that the system can leak due to punctures of the catheter with a needle during an adjustment, undetected puncturing of the balloon with a suture needle during surgery, and partially or completely disconnected catheter-to-port connections. The fluorescent nanoparticles can be delivered to the band, e.g., in a solution, and their disappearance from the band system or their location outside of the band system in the body can be used to indicate the presence of a leak.
In another embodiment, fluorescent nanoparticles can be used to illuminate tissue. For example, the nanoparticles can be applied to a tissue surface in a body cavity to illuminate the body cavity, such as the stomach, uterus, abdominal cavity, thoracic cavity, vaginal canal, nasal passages, and ear canal. By way of non-limiting example, the nanoparticles can be disposed within a gel, such as KY® Jelly, carboxy methyl cellulose, collagen, or hydrogel, and delivered to the uterus by brushing or otherwise applying the particles to an inner surface of the uterus. Upon energy delivery, the nanoparticles are effective to illuminate the uterus, thereby facilitating viewing during a hysterectomy or other procedures. Similarly, the nanoparticles can be applied to an area of tissue within the stomach to thereby illuminate the stomach during various procedures. A person skilled in the art will appreciate that the nanoparticles can be used to illuminate virtually any body cavity.
As indicated above, various devices can be used to apply the particles to a tissue surface, including rigid and flexible devices, such as elongate shafts, syringes, or hand held pens with marking tips configured to coat, inject, or otherwise deliver the nanoparticles to tissue. The markings can also be applied manually using ones finger tips.
In use, as indicated above, the marking device 20 can be inserted through the trocar 26 that extends through a tissue surface and into the abdominal cavity. Endoscopes or other access devices can also optionally be used, and/or the device can be introduced through a natural orifice or through a man-made orifice. Once positioned adjacent to a target tissue, the marking device 20 can be manipulated using, for example, controls to articulate the distal end of the device and controls to actuate the nozzle, to apply the nanoparticles to the tissue surface. A person skilled in the art will appreciate that a variety of marking devices known in the art can be used. By way of non-limiting example, U.S. patent application Ser. No. 11/533,506 of Gill et al., filed on Sep. 20, 2006 and entitled “Dispensing Fingertip Surgical Instrument,” which is incorporated herein by reference in its entirety, discloses one exemplary embodiment of a marking device that can be used to apply nanoparticles to a tissue surface.
In each of the various embodiments disclosed herein the nanoparticles can optionally be delivered in a carrier. The particular composition of the carrier can vary, and suitable carriers include any biocompatible liquid, foam, gel, or solid. The carrier and/or the nanoparticles can also include other substances, such as pharmaceutical and/or therapeutic substances. In one exemplary embodiment a more viscous liquid, foam, or gel is used to prevent or delay the particles from being flushed from the tissue site. Exemplary high viscosity liquids include, by way of non-limiting example, KY® Jelly, carboxy methyl cellulose, collagen, and hydrogel. The solution can also optionally have adhesive properties to help retain the nanoparticles in a desired location. Exemplary adhesives are disclosed, by way of non-limiting example, in U.S. Publication No. 2004/0190975 of Goodman entitled “Applicators, Dispensers and Methods for Dispensing and Applying Adhesive Material,” which is hereby incorporated by reference in its entirety. This reference also discloses various exemplary applicator devices that can be used to deliver nanoparticles to tissue. The nanoparticles can also be combined with existing marking fluids, such as biocompatible dyes, stains, or colored adhesives. A person skilled in the art will appreciate that any carrier can be used.
The composition of the fluorescent nanoparticles can also vary to provide different functions. In one embodiment, a combination of visible and non-visible dyes can be used to form fluorescent nanoparticles for use in marking tissue. Such dual- or multi-wavelength nanoparticles can be delivered to tissue and, once delivered, the visible dyes can be used to quickly locate a tissue containing the particles and the non-visible dyes can provide more precise viewing. By way of non-limiting example, nanoparticles containing visible and non-visible dyes can be delivered to the ureter. Visible dyes located near the surface can be viewed with visible light to help locate the ureter. Once located, an infrared light can be used to see the non-visible dye locating the ureter path located deeper within tissue. Exemplary viewing methods will be discussed in more detail below. While visible fluorescent dyes are preferred, other types of visible dyes may be used in combination with non-visible fluorescent nanoparticles.
In other embodiments, the composition can be adapted to provide a therapeutic effect. For example, a magnetic material can be used with the fluorescent nanoparticles to enable therapeutic energy to be delivered to tissue. Various techniques can be used to associate a magnetic material with the nanoparticles. For example, the particles can be manufactured with a magnetic or magnetic-containing core. Alternatively, the particles can be coated with a magnetic material, or they can be disposed within a magnetic solution. Exemplary magnetic materials include, by way of non-limiting example, iron compounds such as Fe(OH)2 or compounds containing Fe+2 or Fe+3 ions. In use, the magnetic nanoparticles can be applied to tissue to be treated using various methods, including those previously discussed. The location of the particles can be identified using light, and once identified an alternating current can be delivered to the particles to induce inductive heating. As a result, the magnetic nanoparticles will generate heat, thereby cauterizing or otherwise treating the tissue. The use of magnetic particles in combination with fluorescent nanoparticles is particularly advantageous as the fluorescent nanoparticles enable precise identification of the tissue being treated, thereby limiting or avoiding damage to healthy tissue.
In another embodiment, a sensor can be provided for sensing the tissue temperature to enable a desired temperature range to be maintained during energy delivery. The sensor can be disposed on a distal end of a device, such as an endoscope, catheter, or other delivery device, and it can be coupled to an external apparatus that displays the measured temperature. In certain exemplary embodiments, the temperature of the tissue being treated is brought to a temperature above about 150° F. The magnetic particle property may also be used to steer the particle to a preferred location or to cause the particles to accumulate at a preferred location. For example, a magnet can be positioned in the vicinity of the particles, for example, adjacent to an external tissue surface, and the magnet can be manipulated to cause the particles to move in a desired direction.
In another embodiment, fluorescent nanoparticles can be used on medical devices to indicate the location and/or orientation of the device once introduced into a patient's body, or to illuminate a body cavity within which the device is disposed. For example, fluorescent nanoparticles can be coated onto, embedded within, or disposed within an implant to enable future location and identification of the implant. The particles, or a liquid or solid containing the particles, can also be disposed within a capsule or other structure, and that structure can in turn be disposed within an implant. By way of non-limiting example, the nanoparticles can be placed around a port, such as a bolus port in a drug pump or a fluid-refill port in a gastric band.
In yet another embodiment, a catheter, endoscope, or other devices that are introduced into body can have nanoparticles positioned to allow the location of a distal end of the device to be identified during use, to indicate a directional orientation of the device, and/or to illuminate an area surrounding a portion of the device. By way of non-limiting example,
Various exemplary methods and devices are also provided to excite the fluorescent nanoparticles to enable viewing. In an exemplary embodiment, electromagnetic energy can be delivered to fluorescent nanoparticles disposed within a patient's body using a delivery apparatus, such as an endoscope or laparoscope. The delivery apparatus can be located externally, e.g., above the tissue surface, or internally. The excitation source can include any device that can produce electromagnetic energy at wavelengths that correspond to the absorption cross-section of the nanoparticles, including but not limited to, incandescent sources, light emitting diodes, lasers, arc lamps, plasma sources, etc. Various imaging technologies can also be used for detecting, recording, measuring or imaging fluorescent nanoparticles. In an exemplary embodiment, the imaging technology is adapted to reject excitation light, detect fluorescent light, form an image of the location of the nanoparticles, and transmit that image to either a storage or display medium. Exemplary devices include, for example, a flow cytometer, a laser scanning cytometer, a fluorescence micro-plate reader, a fluorescence microscope, a confocal microscope, a bright-field microscope, a high content scanning system, fiber optic cameras, digital cameras, scanned beam imagers, analog cameras, telescopes, microscopes and like devices.
In an exemplary embodiment, the energy source is light, i.e., electromagnetic radiation, and the reading apparatus has an elongate shaft that is adapted to be inserted into a body lumen and that includes a light emitting mechanism and an image receiving apparatus. Since fluorescent nanoparticles formed from a fluorophore core and a silica shell can absorb and emit energy in the visible, infrared, and near infrared frequencies, and they are illuminated at one wavelength and observed at a different shifted wavelength, it is desirable to provide an imaging apparatus that can enable visualization of such nanoparticles.
Additional utilization can also be achieved in the non-visible ranges, as previously indicated, by combining a visible light source with a non-visible light source enabling the ability to turn the non-visible image on or off. The images may be viewed either side by side or simultaneously by overlapping the images. The visible light source can vary and can be an ambient room source, an LED, a laser, a thermal source, an arc source, a fluorescent source, a gas discharge, etc., or various combinations thereof. The light source can also be integrated into the instrument or it may be an independent source that couples to the instrument.
In other embodiments, where the eyepiece on the endoscope is not removable, the mating element can be formed from two halves that mate together to allow the mating element to be positioned around the eyepiece.
In another embodiment, the filter can be removable.
As previously discussed with respect to
One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.