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1.
medRxiv ; 2023 Mar 24.
Article in English | MEDLINE | ID: mdl-36993653

ABSTRACT

Introduction: Placenta accreta spectrum (PAS) occurs when the placenta is pathologically adherent to the myometrium. An intact retroplacental clear space (RPCS) is a marker of normal placentation, but visualization with conventional imaging techniques is a challenge. In this study, we investigate use of an FDA-approved iron oxide nanoparticle, ferumoxytol, for contrast-enhanced magnetic resonance imaging of the RPCS in mouse models of normal pregnancy and PAS. We then demonstrate the translational potential of this technique in human patients presenting with severe PAS (FIGO Grade 3C), moderate PAS (FIGO Grade 1), and no PAS. Methods: A T1-weighted gradient recalled echo (GRE) sequence was used to determine the optimal dose of ferumoxytol in pregnant mice. Pregnant Gab3 -/- mice, which demonstrate placental invasion, were then imaged at day 16 of gestation alongside wild-type (WT) pregnant mice which do not demonstrate invasion. Signal-to-noise ratio (SNR) was computed for placenta and RPCS for all fetoplacental units (FPUs) with ferumoxytol-enhanced magnetic resonance imaging (Fe-MRI) and used for the determination of contrast-to-noise ratio (CNR). Fe-MRI was also performed in 3 pregnant subjects using standard T1 and T2 weighted sequences and a 3D magnetic resonance angiography (MRA) sequence. RPCS volume and relative signal were calculated in all three subjects. Results: Ferumoxytol administered at 5 mg/kg produced strong T1 shortening in blood and led to strong placental enhancement in Fe-MRI images. Gab3 -/- mice demonstrated loss of hypointense region characteristic of the RPCS relative to WT mice in T1w Fe-MRI. CNR between RPCS and placenta was lower in FPUs of Gab3 -/- mice compared to WT mice, indicating higher degrees of vascularization and interruptions throughout the space. In human patients, Fe-MRI at a dose of 5 mg/kg enabled high uteroplacental vasculature signal and quantification of the volume and signal profile in severe and moderate invasion of the placenta relative to a non-PAS case. Discussion: Ferumoxytol, an FDA-approved iron oxide nanoparticle formulation, enabled visualization of abnormal vascularization and loss of uteroplacental interface in a murine model of PAS. The potential of this non-invasive visualization technique was then further demonstrated in human subjects. Diagnosis of placental invasion using Fe-MRI may provide a sensitive method for clinical detection of PAS.

2.
Adv Sci (Weinh) ; 10(10): e2206435, 2023 04.
Article in English | MEDLINE | ID: mdl-36721029

ABSTRACT

The first line of treatment for most solid tumors is surgical resection of the primary tumor with adequate negative margins. Incomplete tumor resections with positive margins account for over 75% of local recurrences and the development of distant metastases. In cases of oral cavity squamous cell carcinoma (OSCC), the rate of successful tumor removal with adequate margins is just 50-75%. Advanced real-time imaging methods that improve the detection of tumor margins can help improve success rates,overall safety, and reduce the cost. Fluorescence imaging in the second near-infrared (NIR-II) window has the potential to revolutionize the field due to its high spatial resolution, low background signal, and deep tissue penetration properties, but NIR-II dyes with adequate in vivo performance and safety profiles are scarce. A novel NIR-II fluorophore, XW-03-66, with a fluorescence quantum yield (QY) of 6.0% in aqueous media is reported. XW-03-66 self-assembles into nanoparticles (≈80 nm) and has a systemic circulation half-life (t1/2 ) of 11.3 h. In mouse models of human papillomavirus (HPV)+ and HPV- OSCC, XW-03-66 outperformed indocyanine green (ICG), a clinically available NIR dye, and enabled intraoperative NIR-II image-guided resection of the tumor and adjacent draining lymph node with negative margins. In vitro and in vivo toxicity assessments revealed minimal safety concerns for in vivo applications.


Subject(s)
Mouth Neoplasms , Papillomavirus Infections , Mice , Animals , Humans , Spectroscopy, Near-Infrared/methods , Indocyanine Green , Fluorescent Dyes/chemistry , Mouth Neoplasms/diagnostic imaging , Mouth Neoplasms/surgery
3.
Nanotechnology ; 34(5)2022 Nov 18.
Article in English | MEDLINE | ID: mdl-36278289

ABSTRACT

The aryl diazonium salt chemistry offers enhancement of near-infrared (NIR) emission of single-walled carbon nanotubes (SWCNTs), although, the attachment of functional molecules which could bring hybrid properties through the process is underdeveloped. In this work, we utilize aryl diazonium salt of fluorescein to createsp3defects on (6,5) SWCNTs. We study the influence of pH on the grafting process identifying that pH 5-6 is necessary for a successful reaction. The fluorescein-modified (6,5) SWCNTs (F-(6,5) SWCNTs) exhibit red-shiftedE11* emission in the NIR region attributed to luminescentsp3defects, but also visible (Vis) fluorescence at 515 nm from surface-attached fluorescein molecules. The fluorescence in both Vis and NIR regions of F-(6,5) SWCNTs exhibit strong pH-dependency associated with the dissociation of fluorescein molecules with an indication of photoinduced-electron transfer quenching the Vis emission of fluorescein dianion. The F-(6,5) SWCNTs could potentially be used for dual-channel medical imaging as indicated by our preliminary experiments. We hope that our research will encourage new, bold modifications of SWCNTs with functional molecules introducing new, unique hybrid properties.

4.
Theranostics ; 12(12): 5504-5521, 2022.
Article in English | MEDLINE | ID: mdl-35910789

ABSTRACT

The abnormal phosphorylation of tau is a necessary precursor to the formation of tau fibrils, a marker of Alzheimer's disease. We hypothesize that hyperphosphorylative conditions may result in unique cell surface markers. We identify and demonstrate the utility of such surrogate markers to identify the hyperphosphorylative state. Methods: Cell SELEX was used to identify novel thioaptamers specifically binding hyperphosphorylative cells. Cell surface vimentin was identified as a potential binding target of the aptamer. Novel molecular magnetic resonance imaging (M-MRI) probes using these aptamers and a small molecule ligand to vimentin were used for in vivo detection of this pre-pathological state. Results: In a mouse model of pathological tau, we demonstrated in vivo visualization of the hyperphosphorylative state by M-MRI, enabling the identification at a pre-pathological stage of mice that develop frank tau pathology several months later. In vivo visualization of the hyperphosphorylative state by M-MRI was further validated in a second mouse model (APP/PS1) of Alzheimer's disease again identifying the mutants at a pre-pathological stage. Conclusions: M-MRI of the hyperphosphorylative state identifies future tau pathology and could enable extremely early-stage diagnosis of Alzheimer's disease, at a pre-patholgical stage.


Subject(s)
Alzheimer Disease , Alzheimer Disease/pathology , Animals , Biomarkers , Disease Models, Animal , Magnetic Resonance Imaging , Mice , Mice, Transgenic , Vimentin , tau Proteins/metabolism
5.
Methods Mol Biol ; 2419: 809-823, 2022.
Article in English | MEDLINE | ID: mdl-35238003

ABSTRACT

Atheromatous lesions are characterized by intrusion into the vascular lumen, resulting in morphological changes to the blood compartment and into the vessel wall, resulting in characteristic molecular and cellular signatures in the solid tissue of the intima, tunica media, adventitia and surrounding tissue. Nanoprobes can be easily formulated to provide long blood-pool residence and molecular targeting, facilitating the imaging of atheromatous changes. Detection of nanoprobes can be accomplished by a variety of methods. We focus in this chapter on the use of cross-sectional imaging techniques, computed tomography (CT) and magnetic resonance imaging (MRI), that facilitate in vivo, noninvasive imaging of the vascular morphology and molecular/cellular signatures of the atheroma. The methods described are suitable for use in animal models, although versions of the probes are being readied for clinical trials, potentially facilitating clinical use in the future.


Subject(s)
Atherosclerosis , Plaque, Atherosclerotic , Adventitia/pathology , Animals , Atherosclerosis/pathology , Magnetic Resonance Imaging/methods , Plaque, Atherosclerotic/diagnostic imaging , Tomography, X-Ray Computed
6.
Sci Rep ; 8(1): 14455, 2018 09 27.
Article in English | MEDLINE | ID: mdl-30262808

ABSTRACT

Fluorescence imaging in the second near-infrared window (NIR-II) holds promise for real-time deep tissue imaging. In this work, we investigated the NIR-II fluorescence properties of a liposomal formulation of indocyanine green (ICG), a FDA-approved dye that was recently shown to exhibit NIR-II fluorescence. Fluorescence spectra of liposomal-ICG were collected in phosphate-buffered saline (PBS) and plasma. Imaging studies in an Intralipid® phantom were performed to determine penetration depth. In vivo imaging studies were performed to test real-time visualization of vascular structures in the hind limb and intracranial regions. Free ICG, NIR-I imaging, and cross-sectional imaging modalities (MRI and CT) were used as comparators. Fluorescence spectra demonstrated the strong NIR-II fluorescence of liposomal-ICG, similar to free ICG in plasma. In vitro studies demonstrated superior performance of liposomal-ICG over free ICG for NIR-II imaging of deep (≥4 mm) vascular mimicking structures. In vivo, NIR-II fluorescence imaging using liposomal-ICG resulted in significantly (p < 0.05) higher contrast-to-noise ratio compared to free ICG for extended periods of time, allowing visualization of hind limb and intracranial vasculature for up to 4 hours post-injection. In vivo comparisons demonstrated higher vessel conspicuity with liposomal-ICG-enhanced NIR-II imaging compared to NIR-I imaging.


Subject(s)
Angiography/methods , Hindlimb , Indocyanine Green , Nanoparticles/chemistry , Optical Imaging/methods , Skull , Animals , Female , Hindlimb/blood supply , Hindlimb/diagnostic imaging , Indocyanine Green/chemistry , Indocyanine Green/pharmacology , Liposomes , Mice , Mice, Nude , Phantoms, Imaging , Skull/blood supply , Skull/diagnostic imaging
7.
PLoS One ; 12(11): e0187563, 2017.
Article in English | MEDLINE | ID: mdl-29121078

ABSTRACT

Indocyanine green (ICG), a FDA approved near infrared (NIR) fluorescent agent, is used in the clinic for a variety of applications including lymphangiography, intra-operative lymph node identification, tumor imaging, superficial vascular imaging, and marking ischemic tissues. These applications operate in the so-called "NIR-I" window (700-900 nm). Recently, imaging in the "NIR-II" window (1000-1700 nm) has attracted attention since, at longer wavelengths, photon absorption, and scattering effects by tissue components are reduced, making it possible to image deeper into the underlying tissue. Agents for NIR-II imaging are, however, still in pre-clinical development. In this study, we investigated ICG as a NIR-II dye. The absorbance and NIR-II fluorescence emission of ICG were measured in different media (PBS, plasma and ethanol) for a range of ICG concentrations. In vitro and in vivo testing were performed using a custom-built spectral NIR assembly to facilitate simultaneous imaging in NIR-I and NIR-II window. In vitro studies using ICG were performed using capillary tubes (as a simulation of blood vessels) embedded in Intralipid solution and tissue phantoms to evaluate depth of tissue penetration in NIR-I and NIR-II window. In vivo imaging using ICG was performed in nude mice to evaluate vascular visualization in the hind limb in the NIR-I and II windows. Contrast-to-noise ratios (CNR) were calculated for comparison of image quality in NIR-I and NIR-II window. ICG exhibited significant fluorescence emission in the NIR-II window and this emission (similar to the absorption profile) is substantially affected by the environment of the ICG molecules. In vivo imaging further confirmed the utility of ICG as a fluorescent dye in the NIR-II domain, with the CNR values being ~2 times those in the NIR-I window. The availability of an FDA approved imaging agent could accelerate the clinical translation of NIR-II imaging technology.


Subject(s)
Indocyanine Green/pharmacology , Optical Imaging/instrumentation , Optical Imaging/methods , Phantoms, Imaging , Animals , Cattle , Chickens , Optical Imaging/standards , Spectroscopy, Near-Infrared/instrumentation , Spectroscopy, Near-Infrared/methods , Spectroscopy, Near-Infrared/standards
8.
Placenta ; 57: 60-70, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28864020

ABSTRACT

INTRODUCTION: Non-invasive 3D imaging that enables clear visualization of placental margins is of interest in the accurate diagnosis of placental pathologies. This study investigated if contrast-enhanced MRI performed using a liposomal gadolinium blood-pool contrast agent (liposomal-Gd) enables clear visualization of the placental margins and the placental-myometrial interface (retroplacental space). Non-contrast MRI and contrast-enhanced MRI using a clinically approved conventional contrast agent were used as comparators. MATERIALS AND METHODS: Studies were performed in pregnant rats under an approved protocol. MRI was performed at 1T using a permanent magnet small animal scanner. Pre-contrast and post-liposomal-Gd contrast images were acquired using T1-weighted and T2-weighted sequences. Dynamic Contrast enhanced MRI (DCE-MRI) was performed using gadoterate meglumine (Gd-DOTA, Dotarem®). Visualization of the retroplacental clear space, a marker of normal placentation, was judged by a trained radiologist. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated for both single and averaged acquisitions. Images were reviewed by a radiologist and scored for the visualization of placental features. Contrast-enhanced CT (CE-CT) imaging using a liposomal CT agent was performed for confirmation of the MR findings. Transplacental transport of liposomal-Gd was evaluated by post-mortem elemental analysis of tissues. Ex-vivo studies in perfused human placentae from normal, GDM, and IUGR pregnancies evaluated the transport of liposomal agent across the human placental barrier. RESULTS: Post-contrast T1w images acquired with liposomal-Gd demonstrated significantly higher SNR (p = 0.0002) in the placenta compared to pre-contrast images (28.0 ± 4.7 vs. 6.9 ± 1.8). No significant differences (p = 0.39) were noted between SNR in pre-contrast and post-contrast liposomal-Gd images of the amniotic fluid, indicating absence of transplacental passage of the agent. The placental margins were significantly (p < 0.001) better visualized on post-contrast liposomal-Gd images. DCE-MRI with the conventional Gd agent demonstrated retrograde opacification of the placenta from fetal edge to the myometrium, consistent with the anatomy of the rat placenta. However, no consistent and reproducible visualization of the retroplacental space was demonstrated on the conventional Gd-enhanced images. The retroplacental space was only visualized on post-contrast T1w images acquired using the liposomal agent (SNR = 15.5 ± 3.4) as a sharply defined, hypo-enhanced interface. The retroplacental space was also visible as a similar hypo-enhancing interface on CE-CT images acquired using a liposomal CT contrast agent. Tissue analysis demonstrated undetectably low transplacental permeation of liposomal-Gd, and was confirmed by lack of permeation through a perfused human placental model. CONCLUSIONS: Contrast-enhanced T1w-MRI performed using liposomal-Gd enabled clear visualization of placental margins and delineation of the retroplacental space from the rest of the placenta; the space is undetectable on non-contrast imaging and on post-contrast T1w images acquired using a conventional, clinically approved Gd chelate contrast agent.


Subject(s)
Contrast Media , Gadolinium , Magnetic Resonance Imaging/methods , Placenta/diagnostic imaging , Animals , Female , Humans , In Vitro Techniques , Liposomes , Pregnancy , Rats , Rats, Sprague-Dawley
10.
Sci Rep ; 6: 27863, 2016 06 14.
Article in English | MEDLINE | ID: mdl-27298076

ABSTRACT

The trans-placental permeability of liposomal Gadolinium (Gd) nanoparticle contrast agents was evaluated in a pregnant mouse model. Pregnant Balb/c mice at 16.5 (±1) days of gestation were imaged using a 3D Spoiled Gradient Echo method at 9.4 T using two contrast agents: a clinically approved Gd chelate, Multihance(®) (gadobenate dimeglumine), and a novel experimental liposomal Gd agent. A Dynamic Contrast Enhancement (DCE) protocol was used to capture the dynamics of contrast entry and distribution in the placenta, and clearance from circulation. A blinded clinical radiologist evaluated both sets of images. A reference region model was used to measure the placental flow and physiological parameters; volume transfer constant (K(trans)), efflux rate constant (K(ep)). The Gd content of excised placentae and fetuses was measured, using inductively coupled plasma mass spectrometry (ICP-MS). MRI images of pregnant mice and ICP-MS analyses of placental and fetal tissue demonstrated undetectably low transplacental permeation of the liposomal Gd agent, while the clinical agent (Multihance) avidly permeated the placental barrier. Image interpretation and diagnostic quality was equivalent between the two contrast agents. Additional testing to determine both maternal and fetal safety of liposomal Gd is suggested.


Subject(s)
Contrast Media/administration & dosage , Echo-Planar Imaging/methods , Fetus/diagnostic imaging , Gadolinium/administration & dosage , Placenta/diagnostic imaging , Uterus/diagnostic imaging , Animals , Female , Male , Maternal-Fetal Exchange , Meglumine/administration & dosage , Meglumine/analogs & derivatives , Mice , Mice, Inbred BALB C , Nanoparticles , Organometallic Compounds/administration & dosage , Pregnancy
11.
Curr Drug Targets ; 16(14): 1582-90, 2015.
Article in English | MEDLINE | ID: mdl-25316273

ABSTRACT

Nanoparticles have considerable potential for cancer imaging and therapy due to their small size and prolonged circulation. However, biological barriers can impede the delivery of a sufficient dose of a drug to the target site, thereby also resulting in the accumulation of toxic compounds within healthy tissues, and systemic toxicity. Multistage nanovectors (MSV) preferentially accumulate on inflamed endothelium, and can thus serve as carriers for drugs and nanoparticles. Herein, we describe the loading of free (i.e., melittin) and nano-encapsulated (i.e., doxorubicin-loaded micelles) drugs into MSV, and report the impact of surface charge and pore size on drug loading. For both drug formulations, negatively charged MSV (i.e., oxidized) with larger pores were shown to retain higher concentrations of payloads compared to positively charged (i.e., APTES-modified) MSV with small pores. Treatment of human umbilical vein endothelial cells (HUVEC) with melittin-loaded MSV (MEL@MSV) resulted in an 80% reduction in cell viability after 3 days. Furthermore, MEL@MSV conjugated with antivascular endothelial growth factor receptor 2 (VEGFR2) antibodies displayed preferential targeting and delivery of MEL to activated HUVEC expressing VEGFR2. Treatment of HUVEC and MCF7 cells with doxorubicin-loaded micelles (DOXNP@MSV) resulted in a 23% and 47% reduction in cell viability, respectively. Taken together, these results demonstrate increased loading of a payload in oxidized, large pore MSV, and effective delivery of free and nano-encapsulated drugs to endothelial and cancer cells.


Subject(s)
Doxorubicin/pharmacology , Endothelial Cells/drug effects , Melitten/pharmacology , Nanoparticles/chemistry , Antibodies/pharmacology , Capsules , Cell Survival/drug effects , Human Umbilical Vein Endothelial Cells , Humans , MCF-7 Cells , Micelles , Molecular Targeted Therapy , Neoplasms/diagnosis , Neoplasms/drug therapy , Vascular Endothelial Growth Factor Receptor-2/metabolism
12.
Circ Cardiovasc Imaging ; 6(2): 285-94, 2013 Mar 01.
Article in English | MEDLINE | ID: mdl-23349231

ABSTRACT

BACKGROUND: The accumulation of macrophages in inflamed atherosclerotic plaques has long been recognized. In an attempt to develop an imaging agent for detection of vulnerable plaques, we evaluated the feasibility of a liposomal-iodine nanoparticle contrast agent for computed tomography imaging of macrophage-rich atherosclerotic plaques in a mouse model. METHODS AND RESULTS: Liposomal-iodine formulations varying in particle size and polyethylene glycol coating were fabricated and shown to stably encapsulate the iodine compound. In vitro uptake studies using optical and computed tomography imaging in the RAW 264.7 macrophage cell line identified the formulation that promoted maximal uptake. Dual-energy computed tomography imaging using this formulation in apolipoprotein E-deficient (ApoE(-/-)) mice (n=8) and control C57BL/6 mice (n=6) followed by spectral decomposition of the dual-energy images enabled imaging of the liposomes localized in the plaque. Imaging cytometry confirmed the presence of liposomes in the plaque and their colocalization with a small fraction (≈2%) of the macrophages in the plaque. CONCLUSIONS: The results demonstrate the feasibility of imaging macrophage-rich atherosclerotic plaques using a liposomal-iodine nanoparticle contrast agent and dual-energy computed tomography.


Subject(s)
Aorta , Aortic Diseases/diagnostic imaging , Aortography/methods , Atherosclerosis/diagnostic imaging , Contrast Media , Nanoparticles , Plaque, Atherosclerotic , Tomography, X-Ray Computed , Triiodobenzoic Acids , Animals , Aorta/metabolism , Aorta/pathology , Aortic Diseases/genetics , Aortic Diseases/metabolism , Aortic Diseases/pathology , Apolipoproteins E/deficiency , Apolipoproteins E/genetics , Atherosclerosis/genetics , Atherosclerosis/metabolism , Atherosclerosis/pathology , Cell Line , Contrast Media/administration & dosage , Contrast Media/metabolism , Disease Models, Animal , Feasibility Studies , Flow Cytometry , Liposomes , Macrophages/diagnostic imaging , Macrophages/metabolism , Macrophages/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout , Microscopy, Fluorescence , Predictive Value of Tests , Time Factors , Triiodobenzoic Acids/administration & dosage , Triiodobenzoic Acids/metabolism
13.
PLoS One ; 7(10): e48515, 2012.
Article in English | MEDLINE | ID: mdl-23119043

ABSTRACT

Extracellular amyloid-ß (Aß) plaques and intracellular neurofibrillary tangles constitute the major neuropathological hallmarks of Alzheimer's disease (AD). It is now apparent that parenchymal Aß plaque deposition precedes behavioral signs of disease by several years. The development of agents that can target these plaques may be useful as diagnostic or therapeutic tools. In this study, we synthesized an Aß-targeted lipid conjugate, incorporated it in stealth liposomal nanoparticles and tested their ability to bind amyloid plaque deposits in an AD mouse model. The results show that the particles maintain binding profiles to synthetic Aß aggregates comparable to the free ligand, and selectively bind Aß plaque deposits in brain tissue sections of an AD mouse model (APP/PSEN1 transgenic mice) with high efficiency. When administered intravenously, these long circulating nanoparticles appear to cross the blood-brain barrier and bind to Aß plaque deposits, labeling parenchymal amyloid deposits and vascular amyloid characteristic of cerebral amyloid angiopathy.


Subject(s)
Alzheimer Disease/genetics , Amyloid beta-Peptides/administration & dosage , Amyloid beta-Protein Precursor/genetics , Presenilin-1/genetics , Administration, Intravenous , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Peptides/chemistry , Amyloid beta-Protein Precursor/metabolism , Animals , Blood-Brain Barrier/metabolism , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Disease Models, Animal , Hippocampus/metabolism , Hippocampus/pathology , Liposomes/chemistry , Mice , Mice, Transgenic , Phosphatidylethanolamines , Plaque, Amyloid , Polyethylene Glycols , Presenilin-1/metabolism , Protein Binding
14.
Oncotarget ; 2(4): 298-304, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21666286

ABSTRACT

Recent developments in multi-functional nanoparticles offer a great potential for targeted delivery of therapeutic compounds and imaging contrast agents to specific cell types, in turn, enhancing therapeutic effect and minimizing side effects. Despite the promise, site specific delivery carriers have not been translated into clinical reality. In this study, we have developed long circulating liposomes with the outer surface decorated with thioated oligonucleotide aptamer (thioaptamer) against E-selectin (ESTA) and evaluated the targeting efficacy and PK parameters. In vitro targeting studies using Human Umbilical Cord Vein Endothelial Cell (HUVEC) demonstrated efficient and rapid uptake of the ESTA conjugated liposomes (ESTA-lip). In vivo, the intravenous administration of ESTA-lip resulted in their accumulation at the tumor vasculature of breast tumor xenografts without shortening the circulation half-life. The study presented here represents an exemplary use of thioaptamer and liposome and opens the door to testing various combinations of thioaptamer and nanocarriers that can be constructed to target multiple cancer types and tumor components for delivery of both therapeutics and imaging agent.


Subject(s)
Antineoplastic Agents/administration & dosage , Aptamers, Nucleotide/therapeutic use , Drug Delivery Systems/methods , Liposomes/therapeutic use , Neoplasms/blood supply , Neoplasms/drug therapy , Angiogenesis Inhibitors/administration & dosage , Angiogenesis Inhibitors/pharmacokinetics , Animals , Antineoplastic Agents/pharmacokinetics , Aptamers, Nucleotide/chemistry , Aptamers, Nucleotide/pharmacokinetics , Breast Neoplasms/blood supply , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Carcinoma/blood supply , Carcinoma/drug therapy , Carcinoma/pathology , Cells, Cultured , Drug Carriers/therapeutic use , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Endothelial Cells/pathology , Female , Humans , Liposomes/chemistry , Liposomes/pharmacokinetics , Mice , Mice, Nude , Models, Biological , Neovascularization, Pathologic/drug therapy , Neovascularization, Pathologic/metabolism , Sulfhydryl Compounds/chemistry , Sulfhydryl Compounds/therapeutic use , Xenograft Model Antitumor Assays
15.
Mol Imaging ; 10(1): 56-68, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21303615

ABSTRACT

In the development of new nanoparticle-based technologies for therapeutic and diagnostic purposes, understanding the fate of nanoparticles in the body is crucial. We recently developed a multistage vector delivery system comprising biodegradable and biocompatible nanoporous silicon particles (first-stage microparticles [S1MPs]) able to host, protect, and deliver second-stage therapeutic and diagnostic nanoparticles (S2NPs) on intravenous injection. This delivery system aims at sequentially overcoming the biologic barriers en route to the target delivery site by separating and assigning tasks to the coordinated logic-embedded vectors constituting it. In this work, by conjugating a near-infrared dye on the surface of the S1MP without compromising the porous structure and potential loading of S2NPs, we were able to monitor the in vivo distribution of S1MPs in healthy mice using an optical imaging system. It was observed that particles predominantly accumulated in the liver and spleen at the end of 24 hours. Further quantification of S1MPs in the major organs of the animals by elemental analysis of silicon using inductively coupled plasma-atomic electron spectroscopy verified the accuracy of in vivo near-infrared imaging as a tool for evaluation of nanovector biodistribution.


Subject(s)
Nanoparticles/analysis , Spectroscopy, Fourier Transform Infrared/methods , Animals , Cell Proliferation/drug effects , Cell Survival/drug effects , Female , Flow Cytometry , Fluorometry , Mice , Nanoparticles/adverse effects , Nanotechnology , Porosity , Silicon
16.
J Biomed Mater Res A ; 94(4): 1236-43, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20694990

ABSTRACT

Injectable and implantable porosified silicon (pSi) carriers and devices for prolonged and controlled delivery of biotherapeutics offer great promise for treatment of various chronic ailments and acute conditions. Polyethylene glycols (PEGs) are important surface modifiers currently used in clinic mostly to avoid uptake of particulates by reticulo-endothelial system (RES). In this work we show for the first time that covalent attachment of PEGs to the pSi surface can be used as a means to tune degradation kinetics of silicon structures. Seven PEGs with varying molecular weights (245, 333, 509, 686, 1214, 3400, and 5000 Da) were employed and the degradation of PEGylated pSi hemispherical microparticles in simulated physiological conditions was monitored by means of ICP-AES, SEM, and fluorimetry. Biocompatibility of the systems with human macrophages in vitro was also evaluated. The results clearly indicate that controlled PEGylation of silicon microparticles can offer a sensitive tool to finely tune their degradation kinetics and that the systems do not induce release of proinflammatory cytokines IL-6 and IL-8 in THP1 human macrophages.


Subject(s)
Polyethylene Glycols/chemistry , Silicon/chemistry , Cell Line , Fluorescence , Humans , Hydrogen-Ion Concentration/drug effects , Interleukin-8/metabolism , Kinetics , Macrophages/drug effects , Macrophages/metabolism , Microscopy, Electron, Scanning , Particle Size , Porosity/drug effects , Silicon/pharmacology
17.
Cancer Res ; 70(9): 3687-96, 2010 May 01.
Article in English | MEDLINE | ID: mdl-20430760

ABSTRACT

RNA interference (RNAi) is a powerful approach for silencing genes associated with a variety of pathologic conditions; however, in vivo RNAi delivery has remained a major challenge due to lack of safe, efficient, and sustained systemic delivery. Here, we report on a novel approach to overcome these limitations using a multistage vector composed of mesoporous silicon particles (stage 1 microparticles, S1MP) loaded with neutral nanoliposomes (dioleoyl phosphatidylcholine, DOPC) containing small interfering RNA (siRNA) targeted against the EphA2 oncoprotein, which is overexpressed in most cancers, including ovarian. Our delivery methods resulted in sustained EphA2 gene silencing for at least 3 weeks in two independent orthotopic mouse models of ovarian cancer following a single i.v. administration of S1MP loaded with EphA2-siRNA-DOPC. Furthermore, a single administration of S1MP loaded with-EphA2-siRNA-DOPC substantially reduced tumor burden, angiogenesis, and cell proliferation compared with a noncoding control siRNA alone (SKOV3ip1, 54%; HeyA8, 57%), with no significant changes in serum chemistries or in proinflammatory cytokines. In summary, we have provided the first in vivo therapeutic validation of a novel, multistage siRNA delivery system for sustained gene silencing with broad applicability to pathologies beyond ovarian neoplasms.


Subject(s)
Nanoparticles/administration & dosage , RNA, Small Interfering/administration & dosage , Silicon/administration & dosage , Animals , Cell Line, Tumor , Female , Gene Silencing , Genetic Therapy/methods , Humans , Liposomes/administration & dosage , Liposomes/chemistry , Liposomes/pharmacokinetics , Mice , Mice, Nude , Nanoparticles/chemistry , Ovarian Neoplasms/genetics , Ovarian Neoplasms/therapy , Phosphatidylcholines/administration & dosage , Phosphatidylcholines/chemistry , RNA, Small Interfering/genetics , RNA, Small Interfering/pharmacokinetics , Receptor, EphA2/genetics , Silicon/chemistry , Silicon/pharmacokinetics , Xenograft Model Antitumor Assays
18.
Biomaterials ; 30(13): 2440-8, 2009 May.
Article in English | MEDLINE | ID: mdl-19215978

ABSTRACT

Endothelial targeting is an approach evolving for drug delivery to the vasculature of pathological lesions. Nano-porous silicon-based multi-functional particles are of particular interest, since they can be manufactured in essentially any size and shape, employing methods of photolithography, to optimize their ability to localize on target endothelia. In this study we tested the impact of surface charge, serum opsonization, and inflammation on the ability of vascular endothelial cells to associate with nano-porous silicon microparticles. Vascular endothelial cells were capable of rapidly internalizing both positive and negative silicon microparticles by an actin-dependent mechanism involving both phagocytosis and macropinocytosis. However, following serum opsonization, internalization was selective for APTES (originally positive) modified microparticles, despite the finding that all opsonized microparticles had a net negative charge. Conversely, macrophages displayed a preference for internalization of serum opsonized oxidized (originally negative) microparticles, supporting the choice of positive microparticles for endothelial targeting. The internalization of opsonized microparticles by endothelial cells was further enhanced by the presence of inflammatory cytokines. These findings suggest that it may be possible to bioengineer silicon microparticles to favor opsonization with proteins that enhance uptake by endothelial cells, without a concurrent enhanced uptake by macrophages.


Subject(s)
Drug Delivery Systems , Endothelial Cells/metabolism , Silicon/chemistry , Veins/cytology , Cells, Cultured , Culture Media, Conditioned , Cytochalasin B/pharmacology , Cytokines/pharmacology , Endothelial Cells/drug effects , Endothelial Cells/ultrastructure , Humans , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Oxidation-Reduction , Particle Size , Phagocytosis , Veins/drug effects , Veins/metabolism , Veins/ultrastructure
19.
Nat Nanotechnol ; 3(3): 151-7, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18654487

ABSTRACT

Many nanosized particulate systems are being developed as intravascular carriers to increase the levels of therapeutic agents delivered to targets, with the fewest side effects. The surface of these carriers is often functionalized with biological recognition molecules for specific, targeted delivery. However, there are a series of biological barriers in the body that prevent these carriers from localizing at their targets at sufficiently high therapeutic concentrations. Here we show a multistage delivery system that can carry, release over time and deliver two types of nanoparticles into primary endothelial cells. The multistage delivery system is based on biodegradable and biocompatible mesoporous silicon particles that have well-controlled shapes, sizes and pores. The use of this system is envisioned to open new avenues for avoiding biological barriers and delivering more than one therapeutic agent to the target at a time, in a time-controlled fashion.


Subject(s)
Contrast Media , Drug Carriers/chemistry , Drug Carriers/pharmacokinetics , Endothelial Cells/metabolism , Nanoparticles/therapeutic use , Silicon/pharmacokinetics , Cells, Cultured , Humans , Porosity
20.
Int J Nanomedicine ; 2(3): 407-18, 2007.
Article in English | MEDLINE | ID: mdl-18019839

ABSTRACT

Nanostructured agglomerated vesicles encapsulating ciprofloxacin were evaluated for modulated delivery from the lungs in a healthy rabbit model. An aliphatic disulfide crosslinker, cleavable by cysteine was used to form cross-links between nanosized liposomes to form the agglomerates. The blood levels of drug after pulmonary instillation of free ciprofloxacin, liposomal ciprofloxacin, and the agglomerated liposomes encapsulating ciprofloxacin were evaluated. The liposomes and agglomerated vesicles showed extended release of drug into the blood over 24 hours, while the free ciprofloxacin did not. The agglomerates also allowed modulation of the drug release rate upon the introduction of cysteine into the lungs post-drug instillation; the cysteine-cleavable agglomerates accelerated their drug release rate, indicated by an increased level of drug in the blood. This technology holds promise for the post-administration modulation of antibiotic release, for the prevention and treatment of pulmonary and systemic infections.


Subject(s)
Ciprofloxacin/pharmacokinetics , Delayed-Action Preparations/pharmacokinetics , Liposomes/chemistry , Lung/metabolism , Nanostructures/chemistry , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/pharmacokinetics , Chemistry, Pharmaceutical/methods , Ciprofloxacin/administration & dosage , Delayed-Action Preparations/administration & dosage , Delayed-Action Preparations/chemistry , Drug Carriers/chemistry , Male , Metabolic Clearance Rate , Nanostructures/ultrastructure , Particle Size , Rabbits
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