Stability Of Indocyanine Green Research Articles

Composite-dissolving microneedle patches for chemotherapy and photothermal therapy in superficial tumor treatment.

A combination of chemotherapy and photothermal therapy (PTT) has emerged as a promising strategy for cancer therapy. To ensure that the chemotherapeutic drug and photothermal agent can be simultaneously delivered to the tumor site to exert their synergistic effects, a safe and efficient delivery system is needed. Herein, we fabricated doxorubicin hydrochloride (DOX)- and indocyanine green (ICG)-loaded microneedle (MN) patches (PVP@DOX/MSN@ICG) using a two-step casting process. Mesoporous silica nanoparticles (MSNs) were used to improve the ICG stability and avoid reducing its PTT efficiency in vivo. The MN patches exhibited a good skin penetration ability, and the tips of the MN patches were dissolved by the interstitial fluid to release DOX and ICG at the tumor sites. Under 808 nm laser irradiation within 2 min, the local temperature in the tumor quickly reached 48 °C at a low power of 0.34 W cm-2. A combination of chemotherapy and PTT for PVP@DOX/MSN@ICG MN patches may maximally induce human osteosarcoma MG-63 cells in vitro. Moreover, the in vivo results showed that PVP@DOX/MSN@ICG MN patches had the best antitumor effects because of synergistic chemotherapy and PTT. Therefore, the composite-dissolving MN patch is a promising strategy for enhancing the antitumor effect of chemotherapy alone and shows the potential for the synergistic therapy of superficial tumors.

Synthesis, characterization, and biological verification of anti-HER2 indocyanine green\u2013doxorubicin-loaded polyethyleneimine-coated perfluorocarbon double nanoemulsions for targeted photochemotherapy of breast cancer cells

BackgroundBreast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among females worldwide. Among various types of breast cancer, the human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer is known to be more aggressive and often resistant to medicinal treatment, leading to an insufficient prognosis and poor susceptibility to chemotherapy and/or hormonal therapy in the current clinic. These circumstances implicate that developing an improved therapeutic strategy rather than persistently changing the anticancer drugs for trying is truly needed to successfully cure this type of breast cancer. In this study, we aimed to fabricate anti-HER2 indocyanine green (ICG)–doxorubicin (DOX)-loaded polyethyleneimine-coated perfluorocarbon double nanoemulsions (HIDPPDNEs) to explore the co-administration of phototherapy and chemotherapy for HER2-overexpressing breast cancer in vitro.ResultsThe HIDPPDNE was first characterized as a sphere-like nanoparticle with surface charge of −57.1 ± 5.6 mV and size of 340.6 ± 4.5 nm, whereas the DOX release rates for the nanodroplets within 48 h in 4 and 37 °C were obtained by 8.13 ± 2.46% and 19.88 ± 2.75%, respectively. We then examined the target-ability of the nanostructure and found that the adhesion efficiency of the HIDPPDNEs onto HER2+ MDA-MB-453 cells was threefold higher than the nanodroplets without anti-HER2 antibody, indicating that the HIDPPDNEs are the product with HER2 binding specificity. In comparison to freely dissolved ICG, the HIDPPDNEs conferred an enhanced thermal stability to the entrapped ICG, and were able to provide a comparable hyperthermia effect and markedly increased production of singlet oxygen under near infrared irradiation (808 nm; 6 W/cm2). Based on the viability analyses, the results showed that the HIDPPDNEs were effective on cell eradication upon near infrared irradiation (808 nm; 6 W/cm2), and the resulting cell mortality was even higher than that caused by using twice amount of encapsulated DOX or ICG alone.ConclusionsThis work demonstrates that the HIDPPDNEs are able to provide improved ICG stability, binding specificity, and enhanced anticancer efficacy as compared to equal dosage of free ICG and/or DOX, showing a high potential for use in HER2 breast cancer therapy with reduced chemotoxicity.

Free DOX and chitosan-N-arginine conjugate stabilized indocyanine green nanoparticles for combined chemophotothermal therapy

Indocyanine green (ICG) is a FDA-approved near-infrared (NIR) cyanine dye used in medical diagnostics. However, the utility of ICG remains limited by its unstable optical property, and concentration-dependent aggregation and precipitation. A chitosan–arginine conjugate (CS-N-Arg) was developed to increase the stability of ICG in physiological buffer saline via formation of strong electrostatic interactions between ICG and CS-N-Arg. The CS-N-Arg/ICG complex prevented ICG from aggregation and precipitation, thus it could serve as a theranostic nanomaterial for image-guided photothermal cancer therapy. The CS-N-Arg/ICG NPs showed excellent photostability, clear fluorescent images, and rapid temperature rise under laser irradiation. Cell viability assay indicated that CS-N-Arg/ICG NPs could efficiently suppress the growth of doxorubicin (DOX) resistant breast cancer cell (MCF-7/ADR cells) under NIR photothermal treatments. In combination of DOX with CS-N-Arg/ICG NPs, a combined effect was observed in MCF-7/ADR breast cancer cells due to dual hyperthermia and chemical therapeutic effects. The present observations suggest that CS-N-Arg/ICG NPs can effectively deliver ICG molecules to MCF-7/ADR breast cancer cells and overcome DOX resistance in the cells by hyperthermia.

Gold nanorods/mesoporous silica-based nanocomposite as theranostic agents for targeting near-infrared imaging and photothermal therapy induced with laser.

Photothermal therapy (PTT) is widely regarded as a promising technology for cancer treatment. Gold nanorods (GNRs), as excellent PTT agent candidates, have shown high-performance photothermal conversion ability under laser irradiation, yet two major obstacles to their clinical application are the lack of selective accumulation in the target site following systemic administration and the greatly reduced photothermal conversion efficiency caused by self-aggregating in aqueous environment. Herein, we demonstrate that tLyp-1 peptide-functionalized, indocyanine green (ICG)-containing mesoporous silica-coated GNRs (I-TMSG) possessed dual-function as tumor cells-targeting near-infrared (NIR) fluorescent probe and PTT agents. The construction of the nanostructure began with synthesis of GNRs by seed-mediated growth method, followed by the coating of mesoporous silica, the chemical conjugation of PEG and tLyp-1 peptide, and the enclosure of ICG as an NIR imaging agent in the mesoporous. The as-prepared nanoparticles could shield the GNRs against their self-aggregation, improve the stability of ICG, and exhibit negligible dark cytotoxicity. More importantly, such a theranostic nanocomposite could realize the combination of GNRs-based photothermal ablation under NIR illumination, ICG-mediated fluorescent imaging, and tLyp-1-enabled more easy endocytosis into breast cancer cells. All in all, I-TMSG nanoparticles, in our opinion, possessed the strong potential to realize the effective diagnosis and PTT treatment of human mammary cancer.

PEDOT nanocomposites mediated dual-modal photodynamic and photothermal targeted sterilization in both NIR I and II window

PEDOT nanoparticles with a suitable nanosize of 17.2 nm, broad adsorption from 700 to 1250 nm, and photothermal conversion efficiency (η) of 71.1%, were synthesized using an environmentally friendly hydrothermal method. Due to the electrostatic attraction between indocyanine green (ICG) and PEDOT, the stability of ICG in aqueous solution was effectively improved. The PEDOT nanoparticles modified with glutaraldehyde (GTA) targeted bacteria directly, and MTT experiments demonstrated the low toxicity of PEDOT:ICG@PEG-GTA in different bacteria and cells. Pathogenic bacteria were effectively killed by photodynamic therapy (PDT) and photothermal therapy (PTT) with PEDOT:ICG@PEG-GTA in the presence of near-infrared (NIR) irradiation (808 nm for PDT, and 1064 nm for PTT). The combination of the two different bacteriostatic methods was significantly more effective than PTT or PDT alone. The obtained PEDOT:ICG@PEG-GTA may be used as a novel synergistic agent in combination photodynamic and photothermal therapy to inactivate pathogenic bacteria in both the NIR I and II window.

Polymer-Protein Hydrogel Nanomatrix for Stabilization of Indocyanine Green towards Targeted Fluorescence and Photoacoustic Bio-imaging.

Indocyanine green (ICG) is an optical contrast agent commonly used for a variety of imaging applications. However, certain limitations of the free dye molecule, concerning its low stability, uncontrolled aggregation and lack of targeting ability, have limited its use. Presented here is a method of embedding ICG in a novel polymer/protein hybrid nanocarrier so as to overcome the above inherent drawbacks of the free molecule. The hybrid nanocarrier consists of a non-toxic and biocompatible polyacrylamide nanoparticle (PAA NP) matrix that incorporates human serum albumin (HSA). This nanocarrier was synthesized through pre-conjugation with HSA and amine functionalized monomer, followed by polymerization using biodegradable cross-linkers, in a water-in-oil emulsion. The ICG dye is loaded into the HSA conjugated PAA nanoparticles (HSA-PAA NPs) through post-loading. Compared to the PAA polymer matrix, the presence of hydrophobic pockets in the HSA-PAA NPs further increases the chemical and physical stability of ICG. This is manifested by lowering the chemical degradation rates under physiological conditions, as well as by improving the thermal- and photo-stability of the dye. A targeting moiety, F3-Cys peptide, was attached to the surface of the NPs, for selective delivery to specific cancer cell lines. The suitability of these NPs for optical imaging applications was demonstrated by performing fluorescence imaging on a rat gliosarcoma cell line (9L). We also present the photoacoustic response of the HSA-PAA NPs, used as imaging contrast agents, in the spectral window of 700 nm to 800 nm.

Abstract 5293: Mixed micelles of triblock copolymers enhance delivery of indocyanine green for fluorescent tumor imaging

Abstract The goal of this study is to develop formulations for non-invasive, near-infrared detection of tumors. Indocyanine green (ICG) is an FDA-approved near-infrared (NIR) imaging agent that is clinically used for angiography and evaluation of liver function. ICG could potentially be used as a NIR fluorescence imaging agent for shallow tumors such as breast cancers. To fulfill this potential, formulations that improve the stability of ICG and direct its accumulation in tumors are necessary. We have previously described Pluronic F127 copolymer micelles that stabilize ICG, enhance its stability, and facilitate tumor accumulation in vivo after systemic administration. A major advantage of Pluronic F127 is its temperature-sensitive behavior that results in more stable micelle formulations at body temperature. However, Pluronic F127 micelles are not stable at room temperature, making micelle preparation and handling challenging. We hypothesized that mixed micelles formed from both Pluronic F127 and a temperature insensitive triblock copolymer composed of poly(ethylene oxide) and poly(3-hydroxybutyrate) (PEO-PHB-PEO), would result in micelles that are both easy to formulate at room temperature and that demonstrate increased stability at body temperature. Micelle formulations with various ratios of Pluronic F127: PEO-PHB-PEO were prepared and loaded with ICG. The micelle stability was determined by assessment of critical micelle concentration measurements, and time-course fluorescence assays were conducted to assess the ability of each micelle formulation to stabilize ICG fluorescence in buffer conditions. The ICG-loaded micelles were administered to tumor-bearing mice by tail vein injection and tumor localization was monitored by non-invasive fluorescence imaging in live mice. The polymer ratio used in micelle formulation was found to play a significant role in the ability of each preparation to stabilize ICG fluorescence Mixed micelles were found to enhance the stability of ICG fluorescence in buffer conditions, and CMC was shown to be dependent on polymer ratios. In vivo, mixed micelles were found to be more effective at maintaining ICG fluorescence in the bloodstream and achieved higher fluorescence signals in the tumor tissues compared with either PEO-PHB-PEO or Pluronic 127 micelles. These results suggest that the mixed micelle formulations offer a promising route to stabilizing these nanoparticles for improved delivery of NIR fluorescent contrast agents to tumors for imaging applications. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5293. doi:10.1158/1538-7445.AM2011-5293

Encapsulation and stabilization of indocyanine green within poly(styrene-alt-maleic anhydride) block-poly(styrene) micelles for near-infrared imaging

Indocyanine green (ICG) is a Federal Drug Administration-approved near-infrared imaging agent susceptible to chemical degradation, nonspecific binding to blood proteins, and rapid clearance from the body. In this study, we describe the encapsulation of ICG within polymeric micelles formed from poly(styrene-alt-maleic anhydride)-block-poly(styrene) (PSMA-b-PSTY) diblock copolymers to stabilize ICG for applications in near-infrared diagnostic imaging. In aqueous solution, the diblock copolymers self-assemble to form highly stable micelles approximately 55 nm in diameter with a critical micelle concentration (CMC) of approximately 1 mg/L. Hydrophobic ICG salts readily partition into the PSTY core of these micelles with high efficiency, and produce no change in micelle morphology or CMC. Once loaded in the micelle core, ICG is protected from aqueous and thermal degradation, with no significant decrease in fluorescence emission over 14 days at room temperature and retaining 63% of its original emission at 37 degrees C. Free ICG does not release rapidly from the micelle core, with only 11% release over 24 h. The ICG-loaded micelles do not exhibit significant cell toxicity. This system has the potential to greatly improve near-infrared imaging in breast cancer detection by increasing the stability of ICG for formulation/administration, and by providing a means to target ICG to tumor tissue.

Healing of rabbits’ cornea following laser welding: effect of solid and semisolid formulations containing indocyanine green

Laser-assisted tissue welding using chromophores and/or biomaterials as solders may offer several advantages over conventional methods (sutures and staples) such as reduced inflammation and foreign body response, faster healing, and simplicity. This technique makes it possible to perform sutureless surgery and repair wounds that are difficult or impossible to repair using standard surgical techniques. This in turn may be particularly important in ophthalmology, where conventional sutures may cause inflammation, tissue injury, scarring, and stenosis. The objective of this research was the preparation and technological and biological characterization of new solid (S) and semisolid (SS) formulations containing indocyanine green (ICG), which is a chromophore commonly used in laser welding or tissue soldering. The formulations were aimed at improving the cromophore-assisted laser welding process while ensuring the chemical stability of ICG. Polyvinyl alcohol (PVA), sodium hyaluronate (HYAL), sodium alginate (ALG), 5-methylpyrrolidinone chitosan (MPCh), and tamarind seed polysaccharide (TSP) were chosen as vehicles for the ocular application of ICG. The wetting and hydrophilicity characteristics of the solid formulations (film) were evaluated by contact angle and swelling measurements and correlated with the in vitro release of ICG. The biological efficacy of the formulations was evaluated on a corneal cut in a rabbit model by monitoring the healing process after laser welding and comparing it to the healing process of a conventional suture. The best results were obtained with a solid formulation based on TSP that showed high wettability, good chemical stability, and slow release of ICG. Its use resulted in a rapid and safe healing process.

Light absorbing properties of indocyanine green (ICG) in solution and after adsorption to the retinal surface — an ex-vivo approach

To evaluate potential differences in light absorbing properties and stability of indocyanine green (ICG) adsorbed to the retinal surface and of ICG dissolved in water and balanced salt solution. The retina of four human donor eyes was prepared by removing the vitreous from the retinal surface. The inner surface of the specimen was covered with two to three drops of a 0.05% or 0.15% ICG solution respectively. After 1 min, the dye was removed by careful irrigation using BSS plus. The retinal specimens were then investigated by diffuse reflection spectroscopy (UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer equipped with a PELA-1020 integrating sphere accessory) and their absorption evaluated by the Kubelka-Munk function. To control the sensitivity of the setting, diffuse reflectance spectra of ICG adsorbed to a cellulose membrane and Al(2)O(3) were measured. For comparison, absorption spectra of ICG dissolved in water and BSS plus solution were measured in relation to ICG concentration and time using an UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer. On the retinal surface, absorption spectra exhibited a steep increase of absorption beginning at 620 nm, with a maximum at 736 nm (0.05%) and a shoulder at 745 (0.15%) and a second maximum at approximately 800 nm for both concentrations. Repeated measurement of the retinal surface 13 days after the ICG exposure revealed no changes in the position of the maxima as compared to the initial measurements. Light absorbing properties of ICG on cellulose or Al(2)O(3) are similar to those seen on the retinal surface with respect to the pattern and location of absorption maxima. In contrast, ICG dissolved in water or BSS plus disclosed variations in absorption characteristics depending on dye concentration, solute and time of measurement. Absorption characteristics and stability of ICG bound to the retinal surface could be of relevance when investigating potential pathomechanisms of ICG related toxicity, which might be related not only to intraoperative but also to postoperative light exposure of patients after intravitreal use of ICG.

Stability of Indocyanine Green in Human Serum Stored at −20 and −70°C

The stability of indocyanine green (ICG) in human serum after storage at -20 and -70 degrees C for an extended time was studied. Serum samples were fortified with ICG at 6.5, 2.0 and 0.3 microgram ml-1, aliquoted, and frozen at -20 or -70 degrees C. The analytic methodology used an internal standard and separation on a reverse phase liquid chromatographic column with UV detection at 240 nm. Samples were prepared for analysis by protein precipitation with acetonitrile. The assay was stability indicating as shown by the complete loss of the ICG peak upon storage at -20 degrees C for 8 weeks. ICG was not stable, as determine by a t test, for 1 week in human serum when stored at -20 degrees C. Storage at -70 degrees C improved stability but the ICG concentration began to fall steadily after 4 weeks of storage.