TECHNOLOGY
Introducing the First Ultra-Focal
Nanoshell Technology
Nanospectra’s proprietary technology platform is demonstrated to be safe and effective in initial clinical trials and viable for multiple applications including solid tumors, tissue and drug delivery.
AUROLASE THERAPY
The company’s principal focus is the development of AuroLase® Therapy for the ablation of solid tumors. Nanospectra’s AuroLase Therapy utilizes the unique ‘optical tunability’ of a new class of nanoparticles, called AuroShells®. These nanoparticles absorb near-infrared wavelengths of light that harmlessly penetrate human tissue. The particles are delivered intravenously and accumulate in the tumor. Then the tumor is illuminated with a near-infrared laser. The particles selectively absorb the photonic laser energy, converting the light into heat, which in turn, destroys the tumor and the blood vessels supplying it; sparing adjacent tissue.
AuroLase Therapy is used with an FDA-cleared laser that emits near-infrared energy with the clinical study specified parameters (power, duty cycle, treatment time) and with an FDA-cleared fiber optic probe for energy delivery percutaneously. AuroShell particles (also known as “nanoshells“) consist of a gold metal shell and a non-conducting silica core and serve as the exogenous absorber of the near-infrared laser energy delivered by the probe.
AuroLase Therapy components include:
- off-the-shelf near-infrared laser source
- off-the-shelf interstitial fiber optic probe for delivery of laser energy to a site near or inside the tumor
- investigational AuroShell particles, a near-infrared absorbing, inert material designed to absorb and convert photonic laser energy into heat
AuroShells: Tumor-Specific Targeting

NORMAL VESSEL ENDOTHELIUM
- Tight junctions in endothelial layer
- Particles unable to pass from blood supply
- Cleared from bloodstream by reticuloendothelial system (RES)

TUMOR VESSEL ENDOTHELIUM
- Gaps in epithelial layer allow particles to pass from blood stream into tumor
- Enhanced Permeability & Retention (RPR) results in tumor specific accumulation of nanoshells
AuroShells are delivered intravenously and due to their small size they are able to accumulate in the tumor through its leaky vasculature. The particles are unable to access normal vasculature and therefore do not accumulate in healthy tissue. Once the particles accumulate in the tumor, the area is illuminated with a near-infrared laser at wavelengths chosen to allow the maximum penetration of light through tissue. The AuroShells are designed to absorb this wavelength and convert the photonic laser energy into heat sufficient to ablate the tumor.
AuroLase for the Ablation
of Prostate Cancer Tissue
AuroLase Therapy for prostate disease is the first and only ultra-focal tissue ablation therapy designed to maximize treatment efficacy while minimizing side effects typically associated with surgery, radiation, and traditional focal therapies. The company is currently conducting a multi-site clinical trial for prostate disease.
Tumor Ablation using AuroLase Therapy
AuroLase® Therapy combines the unique physical and optical properties of AuroShell® particles with a near-infrared laser source to thermally destroy cancer tissue without significant damage to surrounding healthy tissue.
Nanospectra’s proprietary nanoshells circulate freely in the blood stream and collect in the tumor. With state of the art imaging technology, the clinician accurately identifies the lesion and positions the optical fiber probe via targeted MRI Ultrasound fusion technology. The diseased tissue is ablated while sparing the surrounding tissue.
Performed on an outpatient basis, the AuroLase procedure results in significantly fewer side effects enabling the patient to return to a normal lifestyle within days versus weeks. In addition, patients lose no follow-on clinical options.
AuroShell particles are investigational at this current time and only available through designated FDA sanctioned clinical study sites.
SCIENTIFIC PUBLICATIONS
The following includes selected scientific publications regarding the underlying Nanospectra Biosciences technology.
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Gold nanoshells (155 nm in diameter with a coating of polyethylene glycol 5000) were evaluated for preclinical biocompatibility, toxicity, and biodistribution as part of a program to develop an injectable device for use in the photothermal ablation of tumors. The evaluation started with a complete good laboratory practice (GLP) compliant International Organization for Standardization (ISO)-10993 biocompatibility program, including cytotoxicity, pyrogenicity (US Pharmacopeia [USP] method in the rabbit), genotoxicity (bacterial mutagenicity, chromosomal aberration assay in Chinese hamster ovary cells, and in vivo mouse micronucleus), in vitro hemolysis, intracutaneous reactivity in the rabbit, sensitization (in the guinea pig maximization assay), and USP/ISO acute systemic toxicity in the mouse. There was no indication of toxicity in any of the studies. Subsequently, nanoshells were evaluated in vivo by intravenous (iv) infusion using a trehalose/water solution in a series of studies in mice, Sprague-Dawley rats, and Beagle dogs to assess toxicity for time durations of up to 404 days. Over the course of 14 GLP studies, the gold nanoshells were well tolerated and, when injected iv, no toxicities or bioincompatibilities were identified.
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We are developing a novel treatment for high-grade gliomas using near infrared-absorbing silica-gold nanoshells that are thermally activated upon exposure to a near infrared laser, thereby irreversibly damaging cancerous cells. The goal of this work was to determine the efficacy of nanoshell-mediated photothermal therapy in vivo in murine xenograft models. Tumors were induced in male IcrTac:ICR-Prkdc(SCID) mice by subcutaneous implantation of Firefly Luciferase-labeled U373 human glioma cells and biodistribution and survival studies were performed. To evaluate nanoparticle biodistribution, nanoshells were delivered intravenously to tumor-bearing mice and after 6, 24, or 48 h the tumor, liver, spleen, brain, muscle, and blood were assessed for gold content by inductively coupled plasma-mass spectrometry (ICP-MS) and histology. Nanoshell concentrations in the tumor increased for the first 24 h and stabilized thereafter. Treatment efficacy was evaluated by delivering saline or nanoshells intravenously and externally irradiating tumors with a near infrared laser 24 h post-injection. Success of treatment was assessed by monitoring tumor size, tumor luminescence, and survival time of the mice following laser irradiation. There was a significant improvement in survival for the nanoshell treatment group versus the control (P < 0.02) and 57% of the mice in the nanoshell treatment group remained tumor free at the end of the 90-day study period. By comparison, none of the mice in the control group survived beyond 24 days and mean survival was only 13.3 days. The results of these studies suggest that nanoshell-mediated photothermal therapy represents a promising novel treatment strategy for malignant glioma.
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PURPOSE:
Gold nanoshells (NSs) have already shown great promise as photothermal actuators for cancer therapy. Integrin αvβ3 is a marker that is specifically and preferentially overexpressed on multiple tumor types and on angiogenic tumor neovasculature. Active targeting of NSs to integrin αvβ3 offers the potential to increase accumulation preferentially in tumors and thereby enhance therapy efficacy.METHODS:
Enzyme-linked immunosorbent assay (ELISA) and cell binding assay were used to study the in vitro binding affinities of the targeted nanoconjugate NS-RGDfK. In vivo biodistribution and tumor specificity were analyzed using 64Cu-radiolabeled untargeted and targeted NSs in live nude rats bearing head and neck squamous cell carcinoma (HNSCC) xenografts. The potential thermal therapy applications of NS-RGDfK were evaluated by subablative thermal therapy of tumor xenografts using untargeted and targeted NSs.RESULTS:
ELISA and cell binding assay confirmed the binding affinity of NS-RGDfK to integrin αvβ3. Positron emission tomography/computed tomography imaging suggested that tumor targeting is improved by conjugation of NSs to cyclo(RGDfK) and peaks at ~20 hours postinjection. In the subablative thermal therapy study, greater biological effectiveness of targeted NSs was implied by the greater degree of tumor necrosis.CONCLUSION:
The results presented in this paper set the stage for the advancement of integrin αvβ3-targeted NSs as therapeutic nanoconstructs for effective cancer therapy. -
Minimally invasive thermal therapy using high-power diode lasers is an active area of clinical research. Gold nanoshells (AuNS) can be tuned to absorb light in the range used for laser ablation and may facilitate more conformal tumor heating and sparing of normal tissue via enhanced tumor specific heating. This concept was investigated in a xenograft model of prostate cancer (PC-3) using MR temperature imaging (MRTI) in a 1.5T scanner to characterize the spatiotemporal temperature distribution resulting from nanoparticle mediated heating. Tumors with and without intravenously injected AuNS were exposed to an external laser tuned to 808 nm for 180 sec at 4 W/cm(2) under real-time monitoring with proton resonance frequency shift based MRTI. Microscopy indicated that these nanoparticles (140-150 nm) accumulated passively in the tumor and remained close to the tumor microvasculature. MRTI measured a statistically significant (p < 0.001) increase in maximum temperature in the tumor cortex (mean = 21 ± 7°C) in +AuNS tumors versus control tumors. Analysis of the temperature maps helped demonstrate that the overall distribution of temperature within +AuNS tumors was demonstrably higher versus control, and resulted in damage visible on histopathology. This research demonstrates that passive uptake of intravenously injected AuNS in PC-3 xenografts converts the tumor vasculature into a potent heating source for nanoparticle mediated ablation at power levels which do not generate significant damage in normal tissue. When used in conjunction with MRTI, this has implications for development and validation of more conformal delivery of therapy for interstitial laser ablations.
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BACKGROUND AND OBJECTIVES:
Prostate cancer is the most frequent cancer type and the second most common cause of cancer death among US men. This study, adapted a previously reported nanoparticle-directed photothermal treatment of brain tumors to the treatment of prostate disease by using normal canine prostate in vivo, directly injected with a suspension of nanoparticles as a proxy for prostate tumor, and by developing laser dosimetry for prostate which is marginally ablative in native tissue, yet producing photothermal coagulation in prostate tissue containing nanoparticles.METHODS:
Canine prostates were exposed by surgical laparotomy and directly injected with suspensions of nanoparticles (nanoshells) and irradiated by a NIR laser source delivered percutaneously by an optical fiber catheter and isotropic diffuser. The photothermal lesions were permitted to resolve for up to 8 days, at which time each animal was euthanized, necropsied, and the prostate taken for histopathological and elemental analysis.RESULTS:
Nanoparticles were retained for up to 4 hours in prostate and served as a proxy for prostate tumor. A marginally ablative laser dose of 3.0 W for 3 minutes was developed which would yield 4 mm-radius coagulo-necrotic lesions if nanoparticles were present.CONCLUSION:
We have shown that the addition of nanoshells to native tissue, combined with a marginally ablative laser dose can generate ablative thermal lesions, and that the radial extent of the thermal lesions is strictly confined to within ∼4 mm of the optical fiber with sub-millimeter uncertainty. This, in turn, suggests a means of precise tumor ablation with an ability to obviate damage to critical structures limited primarily by the precision with which the optical fiber applicator can be placed. In so doing, it should be possible to realize a precise, nerve bundle and urethra sparing prostate cancer treatment using a minimally invasive, percutaneous approach. -
BACKGROUND AND OBJECTIVES:
Gold nanoparticles (GNPs) such as gold nanoshells (GNSs) and gold nanorods (GNRs) have been explored in a number of in vitro and in vivo studies as imaging contrast and cancer therapy agents due to their highly desirable spectral and molecular properties. While the organ-level biodistribution of these particles has been reported previously, little is known about the cellular level or intra-organ biodistribution. The objective of this study was to demonstrate the use of intrinsic two-photon induced photoluminescence (TPIP) to study the cellular level biodistribution of GNPs.STUDY DESIGN/MATERIALS AND METHODS:
Tumor xenografts were created in twenty-seven male nude mice (Swiss nu/nu) using HCT 116 cells (CCL-247, ATCC, human colorectal cancer cell line). GNSs and GNRs were systemically injected 24 hr. prior to tumor harvesting. A skin flap with the tumor was excised and sectioned as 8 μm thick tissues for imaging GNPs under a custom-built multiphoton microscope. For multiplexed imaging, nuclei, cytoplasm, and blood vessels were demonstrated by hematoxylin and eosin (H&E) staining, YOYO-1 iodide staining and CD31-immunofluorescence staining.RESULTS:
Distribution features of GNPs at the tumor site were determined from TPIP images. GNSs and GNRs had a heterogeneous distribution with higher accumulation at the tumor cortex than tumor core. GNPs were also observed in unique patterns surrounding the perivascular region. While most GNSs were confined at the distance of approximately 400 μm inside the tumor edge, GNRs were shown up to 1.5 mm penetration inside the edge.CONCLUSIONS:
We have demonstrated the use of TPIP imaging in a multiplexed fashion to image both GNPs and nuclei, cytoplasm, or vasculature simultaneously. We also confirmed that TPIP imaging enabled visualization of GNP distribution patterns within the tumor and other critical organs. These results suggest that direct luminescence-based imaging of metal nanoparticles holds a valuable and promising position in understanding the accumulation kinetics of GNPs. In addition, these techniques will be increasingly important as the use of these particles progress to human clinical trials where standard histopathology techniques are used to analyze their effects.