Construction of fibrin-targeted nanoparticles for imaging diagnosis and treatment of arterial thrombosis

The clinical application of conventional thrombolytic drugs is limited due to the difficulty in precisely targeting the thrombus site and side effects such as severe bleeding. In order to specifically image thrombus for diagnosis and thrombolytic therapy, a CREKA-targeted and pH-responsive drug release nano-delivery system, called LK/PDB/IR820-CREKA NPs, was constructed. In vitro experiments showed that NPs had good pH responsiveness and biocompatibility. The in vitro thrombolytic rate was as high as 46% and the NPs had a strong thrombus-binding ability. In an FeCl3-induced carotid artery thrombosis mouse model, PDB/IR820-CREKA NPs could specifically target thrombus, which enabled accurate diagnosis of thrombus sites. Targeted nanoparticle-encapsulated lumbrokinase at a dose of 900 U per 10 g significantly reduced the total protein content at the thrombus site, while reducing the risk of non-specific bleeding. Based on the thrombus-specific imaging and therapeutic activity, this nano-delivery system has the potential to be used for the treatment of thrombotic vascular diseases.

Effect of oxygen generating nanozymes on indocyanine green and IR 820 mediated phototherapy against oral cancer

The hypoxic environment within a solid tumor is a limitation to the effectiveness of photodynamic therapy. Here, we demonstrate the use of oxygen generating nanozymes (CeO2, Fe3O4, and MnO2) to improve the photodynamic effect. The optimized combination of process parameters for irradiation was obtained using the Box Behnken experimental design. Indocyanine green, IR 820, and their different combinations with oxygen generators were studied for their effect on oral carcinoma. Dynamic light scattering technique showed the average particle size of CeO2, MnO2, and Fe3O4 to be 211 ± 16, and 157 ± 28, 143 ± 19 nm with PDI of 0.23, 0.28 and 0.20 and a zeta potential of -2.6 ± 0.45, -2.4 ± 0.60 and  -6.1 ± 0.23 mV, respectively. The formation of metal oxides was confirmed using UV-visible, FTIR, and X-ray photon spectroscopies. The amount of dissolved oxygen produced by CeO2, MnO2, and Fe3O4 in the presence of H2O2 within 2 min was 1.7 ± 0.15, 1.7 ± 0.16, and 1.4 ± 0.12 mg/l, respectively. Growth inhibition studies in the FaDu oral carcinoma spheroid model showed a significant (P < 0.05) increase in growth reduction from 81 ± 2.9 and 88 ± 2.1% to 97 ± 1.2 and 99 ± 1.0% for ICG and IR 820, respectively, after irradiation (808 nm laser, 1 W/cm2, 5 min) in the presence of CeO2 (25 μg/ml). In conclusion, oxygen-generating nanozymes can improve the photodynamic effect of ICG and IR 820.

Enhancing Photothermal/Photodynamic Therapy for Glioblastoma by Tumor Hypoxia Alleviation and Heat Shock Protein Inhibition Using IR820-Conjugated Reduced Graphene Oxide Quantum Dots

We use low-molecular-weight branched polyethylenimine (PEI) to produce cytocompatible reduced graphene oxide quantum dots (rGOQD) as a photothermal agent and covalently bind it with the photosensitizer IR-820. The rGOQD/IR820 shows high photothermal conversion efficiency and produces reactive oxygen species (ROS) after irradiation with near-infrared (NIR) light for photothermal/photodynamic therapy (PTT/PDT). To improve suspension stability, rGOQD/IR820 was PEGylated by anchoring with the DSPE hydrophobic tails in DSPE-PEG-Mal, leaving the maleimide (Mal) end group for covalent binding with manganese dioxide/bovine serum albumin (MnO2/BSA) and targeting ligand cell-penetrating peptide (CPP) to synthesize rGOQD/IR820/MnO2/CPP. As MnO2 can react with intracellular hydrogen peroxide to produce oxygen for alleviating the hypoxia condition in the acidic tumor microenvironment, the efficacy of PDT could be enhanced by generating more cytotoxic ROS with NIR light. Furthermore, quercetin (Q) was loaded to rGOQD through π-π interaction, which can be released in the endosomes and act as an inhibitor of heat shock protein 70 (HSP70). This sensitizes tumor cells to thermal stress and increases the efficacy of mild-temperature PTT with NIR irradiation. By simultaneously incorporating the HSP70 inhibitor (Q) and the in situ hypoxia alleviating agent (MnO2), the rGOQD/IR820/MnO2/Q/CPP can overcome the limitation of PTT/PDT and enhance the efficacy of targeted phototherapy in vitro. From in vivo study with an orthotopic brain tumor model, rGOQD/IR820/MnO2/Q/CPP administered through tail vein injection can cross the blood-brain barrier and accumulate in the intracranial tumor, after which NIR laser light irradiation can shrink the tumor and prolong the survival times of animals by simultaneously enhancing the efficacy of PTT/PDT to treat glioblastoma.

JS-K Combined with a Melanin-Based Theranostic Agent: A Novel Sequential Delivery Strategy to Enhance the Near-Infrared Fluorescence Imaging of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a 5 year survival rate less than 12%. This malignancy is closely related to the unique tumor microenvironment (TME), which is characterized by a hypovascular and hyperdense extracellular matrix, making it difficult for drugs to permeate the tumor center. Near-infrared fluorescence (NIRF) imaging, which has high sensitivity and resolution, may improve the survival rate of PDAC patients. In this study, we first used JS-K (O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl) piperazine-1-yl] diazene-1-ium-1,2-diolate) to specifically dilate blood vessels within the TME of PDAC patients and subsequently injected IR820-PEG-MNPs (IPM NPs) to diagnose and treat orthotopic PDAC. We found that JS-K promoted the accumulation of IPM NPs in orthotopic Pan02 tumor-bearing mice and was able to increase the tumor signal-to-background ratio (SBR) in the orthotopic PDAC area by 41.5%. In addition, surgical navigation in orthotopic Pan02 tumor-bearing mice and complete tumor resection based on fluorescence imaging were achieved with a detection sensitivity of 81.0%. Moreover, we verified the feasibility of the combination of laparoscopy and photothermal ablation (PTA) for the treatment of PDAC. Finally, we demonstrated that IPM NPs had greater affinity for human PDAC tissues than for normal pancreatic tissues ex vivo, preliminarily highlighting the potential for clinical translation of these NPs. In conclusion, we developed and validated a novel sequential delivery strategy that promotes the accumulation of nanoagents in the tumor area and can be used for the diagnosis and treatment of PDAC.

Biotin-new indocyanine green conjugate: Synthesis, in vitro photocytotoxicity and in vivo biodistribution

New indocyanine green (ICG) (IR820) is one of the ICG derivatives and attracts increasing attention for cancer management. However, the unsatisfactory tumor targeting ability of IR820 significantly limits its applications for cancer theranostics. Biotin receptor is overexpressed on the membrane of various tumor cells and biotin modified nanocarriers have been reported to enhance the tumor targeting ability on several tumor types. In this work, biotin-new ICG conjugate (Biotin-SS-IR820) was prepared for tumor-targeted IR820 delivery. Biotin and IR820 were coupled through cystamine. The synthesized Biotin-SS-IR820 was characterized by 1 H NMR, FT-IR and HRMS. The in vitro singlet oxygen generation study shows that Biotin-SS-IR820 exhibits similar singlet oxygen generation as compared to IR820 upon 660 nm laser irradiation (0.8 W/cm2 ). The cellular uptake study shows that Biotin-SS-IR820 shows enhanced cellular uptake amount as compared to IR820 on 4T1 cells. As a result, Biotin-SS-IR820 displays enhanced in vitro photodynamic therapeutic effect against 4T1 cells as compared to IR820. In in vivo biodistribution study, Biotin-SS-IR820 shows enhanced tumor accumulation as compared to IR820. Biotin-SS-IR820 developed in this work shows promising prospects for targeted delivery of IR820 to biotin receptor overexpressed tumors.

Deciphering the Role of H-Ferritin Nanocages in Improving Tumor-Targeted Delivery of Indocyanine Green: Combined Analysis of Murine Tissue Homogenates with UHPLC-MS/MS and Fluorescence

We investigated the relevance of encapsulation in H-ferritin nanocages (HFn) in determining an improved tumor-targeted delivery of indocyanine green (ICG). Since from previous experiments, the administration of HFn loaded with ICG (HFn-ICG) resulted in an increased fluorescence signal of ICG, our aim was to uncover if the nanoformulation could have a major role in driving a specific targeting of the dye to the tumor or rather a protective action on ICG's fluorescence. Here, we took advantage of a combined analysis involving ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) on murine tissue homogenates matched with fluorescence intensities analysis detected by ex vivo optical imaging. The quantification of ICG content performed on different organs over time combined with the fluorescent signal detection confirmed the superior delivery of ICG thanks to the nanoformulation. Our results showed that HFn-ICG drives a real accumulation at the tumor instead of only having a role in the preservation of ICG's fluorescence, further supporting its use as a delivery system of ICG for fluorescence-guided surgery applications in oncology.

Adjustable Fluorescence Emission of J-Aggregated Tricarbocyanine in the Near-Infrared-II Region

Near-infrared (NIR) J-aggregates attract increasing attention in many areas, especially in biomedical applications, as they combine the advantages of NIR spectroscopy with the unique J-aggregation properties of organic dyes. They enhance light absorption and have been used as effective biological imaging and therapeutic agents to achieve high-resolution imaging or effective phototherapy in vivo. In this work, we present novel J-aggregates composed of the well-known cyanine molecules. Cyanines are one of the few types of molecules whose absorption and emission can be shifted over a broad spectral range, from the ultraviolet (UV) to the NIR regime. They can easily transform into J-aggregates with narrow absorption and emission peaks, which is accompanied by a red shift in their spectra. In this work, we show, for the first time, that the tricarbocyanine dye (IR 820) has two sharp fluorescence emission bands in the NIR-II region with high photostability. These emission bands can be tuned to a desired wavelength in the range of 1150-1560 and 1675 nm, with a linear dependence on the excitation wavelength. Cryogenic transmission electron microscopy (cryo-TEM) images are presented, and combined with molecular modeling analysis, they confirm IR 820 π-stacked self-assembled fibrous structures.

Combined Doxorubicin Mesoporous Carbon Nanospheres for Effective Tumor Lymphatic Metastasis by Multi-Modal Chemo-Photothermal Treatment in vivo

Introduction

Sentinel lymph node (SLN) is the first regional lymph node where tumor cells metastasize, and its identification and treatment are of great significance for the prevention of tumor metastasis. However, the current clinical modalities for identification and treatment of SLN are still far from satisfactory owing to their high cost, invasiveness and low accuracy. We aim to design a novel nanomedicine system for SLN imaging and treatment with high efficacy.

Methods

We designed and prepared hollow mesoporous carbon spheres (HMCS) and loaded with the chemotherapeutic drug doxorubicin (DOX), which is then modified with polyvinyl pyrrolidone (PVP) to obtain nanomedicine: HMCS-PVP-DOX.

Results

HMCS-PVP with a size of about 150 nm could retain in the lymph nodes for a long time and stain the lymph nodes, which could be easily observed by the naked eye. At the same time, HMCS-PVP exhibited excellent photoacoustic and photothermal imaging capabilities, realizing multimodal imaging to locate lymph nodes precisely. Due to its high specific surface area, HMCS could be largely loaded with the chemotherapeutic drug doxorubicin (DOX). HMCS-PVP-DOX displayed highly efficient synergistic chemotherapy-photothermal therapy for lymphatic metastases in both cellular and animal experiments due to its significant photothermal effect under 1064 nm laser irradiation. HMCS-PVP-DOX also displayed great stability and biosafety.

Discussion

Multifunctional nanomedicine HMCS-PVP-DOX is expected to provide a novel paradigm for designing nanomedicine to the diagnosis and treatment of lymphatic metastases because of its good stability and safety.

Short-wave infrared fluorescence imaging of near-infrared dyes with robust end-tail emission using a small-animal imaging device

Commercially available near-infrared (NIR) dyes, including indocyanine green (ICG), display an end-tail of the fluorescence emission spectrum detectable in the short-wave infrared (SWIR) window. Imaging methods based on the second NIR spectral region (1,000-1,700 nm) are gaining interest within the biomedical imaging community due to minimal autofluorescence and scattering, allowing higher spatial resolution and depth sensitivity. Using a SWIR fluorescence imaging device, the properties of ICG vs. heptamethine cyanine dyes with emission >800 nm were evaluated using tissue-simulating phantoms and animal experiments. In this study, we tested the hypothesis that an increased rigidity of the heptamethine chain may increase the SWIR imaging performance due to the bathochromic shift of the emission spectrum. Fluorescence SWIR imaging of capillary plastic tubes filled with dyes was followed by experiments on healthy animals in which a time series of fluorescence hindlimb images were analyzed. Our findings suggest that higher spatial resolution can be achieved even at greater depths (>5 mm) or longer wavelengths (>1,100 nm), in both tissue phantoms and animals, opening the possibility to translate the SWIR prototype toward clinical application.

Optical Characteristics of Indocyanine Green J-Aggregates Induced by Cisplatin for Phototheranostic Applications

The development of an optical system for combinatorial theranostics is of significant interest. Clinical translation of such theranostic agents need to cross several barriers. Herein, we have developed a facile method for the preparation of J-aggregates using FDA approved agents, namely, NIR fluorophore indocyanine green (ICG) and a chemotherapeutic drug, cisplatin (CDDP), which induces ICG to form indocyanine green J-aggregates (IJAs). The formation of IJAs has been characterized by the formation of a new absorption peak centered at ∼896 nm. The existing methods to synthesize IJAs have used several harsh reaction conditions, such as elevated temperatures, for a prolonged time duration (∼60 days). To the best of our knowledge, for the first time, we have reported the formation of IJAs assisted by CDDP at 37 °C temperature within 12 h. The presence of CDDP in ICG favors IJA formation and thereby reduces the harshness of the reaction conditions in the conventionally followed protocols. Moreover, the presence of CDDP can facilitate photoactivated combinatorial therapy. The as synthesized IJA optical system has superior properties to those of free ICG, in terms of diagnostic and therapeutic capabilities (being activatable at ∼896 nm wavelength, which can achieve deeper tissue penetration) and excellent optical and storage stability. The facile synthesis proposed along with CDDP incorporation makes the optical system a clinically relevant one-component theranostic agent.

Tumor-Targeted Polydopamine-Based Nanoparticles for Multimodal Mapping Following Photothermal Therapy of Metastatic Lymph Nodes

PURPOSE

Lymphadenectomy with lymph node (LN) mapping is essential for surgical removal of solid tumors. Existing agents do not provide accurate multimodal mapping and antitumor therapy for metastatic LNs; therefore, we fabricated a polydopamine (PDA) nanoparticle (NP)-based tumor-targeted LN mapping agent capable of multimodal mapping and guided photothermal therapy (PTT) for metastatic LNs.

MATERIALS AND METHODS

PDA NPs modified with polyethylene glycol (PEG) were obtained by polymerization under alkaline conditions. The PEG-PDA NPs were loaded with the circular tripeptide Arg-Gly-Asp (cRGD) to achieve tumor-targeting capacity and with the fluorescent dye IR820 and magnetic resonance imaging (MRI) contrast Gd(NH2)2 for in situ detection. The resulting cRGD-PEG-PDA@IR820/Gd(NH2)2 (cRGD-PPIG) NPs were tested for their biosafety and metastatic LN mapping ability. They were drained specifically into LNs and selectively taken up by gastric MKN45 cells via αvβ3 integrin-mediated endocytosis.

RESULTS

This phenomenon enabled MR/optical/near-infrared fluorescence multimodal metastatic LN mapping, guiding the creation of accurate and highly efficient PTT for gastric cancer metastatic LNs in mice.

CONCLUSION

In summary, we fabricated tumor-targeted cRGD-PPIG NPs with MR/optical/near-infrared fluorescence multimodal metastatic LN mapping capacity for surgery and efficient PTT guidance post-surgery.

Modulation of Local Cellular Activities using a Photothermal Dye-Based Subcellular-Sized Heat Spot

Thermal engineering at the microscale, such as the regulation and precise evaluation of the temperature within cellular environments, is a major challenge for basic biological research and biomaterials development. We engineered a polymeric nanoparticle having a fluorescent temperature sensory dye and a photothermal dye embedded in the polymer matrix, named nanoheater-thermometer (nanoHT). When nanoHT is illuminated with a near-infrared laser at 808 nm, a subcellular-sized heat spot is generated in a live cell. Fluorescence thermometry allows the temperature increment to be read out concurrently at individual heat spots. Within a few seconds of an increase in temperature by approximately 11.4 °C from the base temperature (37 °C), we observed the death of HeLa cells. The cell death was observed to be triggered from the exact local heat spot at the subcellular level under the fluorescence microscope. Furthermore, we demonstrate the application of nanoHT for the induction of muscle contraction in C2C12 myotubes by heat release. We successfully showed heat-induced contraction to occur in a limited area of a single myotube based on the alteration of protein-protein interactions related to the contraction event. These results demonstrate that even a single heat spot provided by a photothermal material can be extremely effective in altering cellular functions.

Real-time 3D optoacoustic tracking of cell-sized magnetic microrobots circulating in the mouse brain vasculature

Mobile microrobots hold remarkable potential to revolutionize health care by enabling unprecedented active medical interventions and theranostics, such as active cargo delivery and microsurgical manipulations in hard-to-reach body sites. High-resolution imaging and control of cell-sized microrobots in the in vivo vascular system remains an unsolved challenge toward their clinical use. To overcome this limitation, we propose noninvasive real-time detection and tracking of circulating microrobots using optoacoustic imaging. We devised cell-sized nickel-based spherical Janus magnetic microrobots whose near-infrared optoacoustic signature is enhanced via gold conjugation. The 5-, 10-, and 20-μm-diameter microrobots are detected volumetrically both in bloodless ex vivo tissues and under real-life conditions with a strongly light-absorbing blood background. We further demonstrate real-time three-dimensional tracking and magnetic manipulation of the microrobots circulating in murine cerebral vasculature, thus paving the way toward effective and safe operation of cell-sized microrobots in challenging and clinically relevant intravascular environments.

Rational synthesis of IR820-albumin complex for NIR-II fluorescence imaging-guided surgical treatment of tumors and gastrointestinal obstruction

IR820, an analog of FDA-approved indocyanine green, is a promising second near-infrared window (NIR-II) fluorescence probe with better NIR-II fluorescence stability and great clinical transformation potential. Moreover, its fluorescence can be further remarkably enhanced by the interaction with albumin. Therefore, it is significant to flexibly design IR820-albumin complex using endogenous or exogenetic albumin to meet the requirements of different biological applications. Herein, we show the rational synthesis of IR820-albumin complex for NIR-II fluorescence imaging-guided surgical treatment of tumors and gastrointestinal obstruction. We compared the NIR-II fluorescence imaging ability of IR820 pre-incubated with albumin or not to visualize tumors and the gastrointestinal tract in vivo and found that the formation of IR820-albumin was essential for the intense NIR-II fluorescence. For imaging-guided tumor treatment, after intravenous injection of free IR820, IR820-albumin complex can be formed in vivo due to the presence of plenty of albumin in the blood. For imaging-guided gastrointestinal obstruction removal, IR820-albumin complex should be synthesized in vitro before oral administration. NIR-II fluorescence imaging-guided surgeries were successfully realized in both tumor resection and gastrointestinal obstruction removal. Besides, toxicity assessments in vitro and in vivo confirmed the good biocompatibility of IR820. Our study provides a flexible paradigm for IR820-based NIR-II fluorescence imaging and surgical navigation towards different diseases.

Investigation of nonlinear photoacoustic microscopy using a low-cost infrared lamp

Nonlinear photoacoustic microscopy (PAM) is a novel approach to enhance contrast and resolution. In this study, a low-cost infrared (IR) lamp as a simple approach for nonlinear PAM is demonstrated. Numerical simulations are first performed to verify the nonlinear photoacoustic effect under steady heating for two cases: (a) Differentiation of absorbers with different Grüneisen coefficients; (b) enhancement of photoacoustic amplitude. Then, sets of experiments are conducted to experimentally demonstrate our proposed approach: (a) Longitudinal monitoring of photoacoustic A-line signals from two samples, porcine tissue ex vivo and hemoglobin and indocyanine green (ICG) solutions in tubes in vitro for demonstrating the above-mentioned two cases; (b) PAM imaging of hemoglobin and ICG solutions in tubes before and after IR lamp heating. Different signal change and amplitude enhancement are observed in different demonstrations, showing the efficacy of the proposed approach. By virtue of cost-effectiveness and decent performance, our work facilitates nonlinear PAM studies.

Bio-engineered nano-vesicles for IR820 delivery: a therapy platform for cancer by surgery and photothermal therapy

Long-term unsolved health problems from pre-/intra-/postoperative complications and thermal ablation complications pose threats to liver-cancer patients. To reduce the threats, we propose a multimodal-imaging guided surgical navigation system and photothermal therapy strategy to improve specific labeling, real-time monitoring and effective treatment of hepatocellular carcinoma. Using a bioengineering approach, G-Nvs@IR820, a kind of human-cell-membrane nano-vesicle, was generated with growth arrest-specific 6 (Gas6) expressed on the membrane and with near-infrared absorbing dye (IR820) loaded into it, which is proven to be an effective nanoparticle-drug-delivery system for Axl-overexpressing hepatocellular carcinoma. G-Nvs@IR820 shows excellent features in vitro and in vivo. As Gas6 binds to Axl specifically, G-Nvs@IR820 has good targeting ability to the tumor site and also has a good ability to guide the further accurate obliteration of carcinoma from adjacent normal tissue in surgery with its highly resolved fluorescence/photoacoustic/surgical-navigation signals. Moreover, the G-Nvs@IR820 represented a new perspective for photothermal therapy. Briefly, Nvs@IR820 was synthesized at a gram scale with high affinity, specificity, and safety. It has promising potential in clinical application for IGS and PTT in Axl-overexpressing hepatoma carcinoma.

Heptamethine Cyanine–Based Application for Cancer Theranostics

Cancer is the most common life-threatening malignant disease. The future of personalized cancer treatments relies on the development of functional agents that have tumor-targeted anticancer activities and can be detected in tumors through imaging. Cyanines, especially heptamethine cyanine (Cy7), have prospective application because of their excellent tumor-targeting capacity, high quantum yield, low tissue autofluorescence, long absorption wavelength, and low background interference. In this review, the application of Cy7 and its derivatives in tumors is comprehensively explored. Cy7 is enormously acknowledged in the field of non-invasive therapy that can “detect” and “kill” tumor cells via near-infrared fluorescence (NIRF) imaging, photothermal therapy (PTT), and photodynamic therapy (PDT). Furthermore, Cy7 is more available and has excellent properties in cancer theranostics by the presence of multifunctional nanoparticles via fulfilling multimodal imaging and combination therapy simultaneously. This review provides a comprehensive scope of Cy7’s application for cancer NIRF imaging, phototherapy, nanoprobe-based combination therapy in recent years. A deeper understanding of the application of imaging and treatment underlying Cy7 in cancer may provide new strategies for drug development based on cyanine. Thus, the review will lead the way to new types with optical properties and practical transformation to clinical practice.

Enhanced photothermal heating and combination therapy of NIR dye via conversion to self-assembled ionic nanomaterials

Combination nanodrugs are promising therapeutic agents for cancer treatment. However, they often require the use of complex nanovehicles for transportation into the tumor site. Herein, a new class of carrier-free ionic nanomaterials (INMs) is presented, which are self-assembled by the drug molecules themselves. In this regard, a photothermal therapy (PTT) mechanism is combined with a chemotherapy (chemo) mechanism using ionic liquid chemistry to develop a combination drug to deliver multiple cytotoxic mechanisms simultaneously. Nanodrugs were developed from an ionic material-based chemo-PTT combination drug by using a simple reprecipitation method. Detailed examination of the photophysical properties (absorption, fluorescence emission, quantum yield, radiative and non-radiative rate) of the INMs revealed significant spectral changes which are directly related to their therapeutic effect. The reactive oxygen species quantum yield and the light to heat conversion efficiency of the photothermal agents were shown to be enhanced in combination nanomedicines as compared to their respective parent compounds. The ionic nanodrugs exhibited an improved dark and light cytotoxicity in vitro as compared to either the chemotherapeutic or photothermal parent compounds individually, due to a synergistic effect of the combined therapies, improved photophysical properties and their nanoparticles' morphology that enhanced the cellular uptake of the drugs. This study presents a general framework for the development of carrier-free dual-mechanism nanotherapeutics.

Apoferritin and Dps as drug delivery vehicles: Some selected examples in oncology

BACKGROUND

The ideal nanoparticle should be able to encapsulate either pharmaceutical agents or imaging probes so that it could treat or image clinical tumours by targeting the cancer site efficiently. Further, it would be an added advantage if it demonstrates: small size, built in targeting, biocompatibility and biodegradability. Ferritin, which is an endogenous self-assembling protein, stores iron and plays a role in iron homeostasis. When iron atoms are removed apoferritin (AFt) is formed which consists of a hollow shell where it can be used to load guest molecules. Due to its unique architecture, AFt has been investigated as a versatile carrier for tumour theranostic applications. DNA-binding protein from starved cells (Dps), which also belongs to the ferritin family, is a protein found only in prokaryotes. It is used to store iron and protect chromosomes from oxidative damage; because of its architecture, Dps could also be used as a delivery vehicle.

CONCLUSIONS

Both these nano particles are promising in the field of oncology, especially due to their stability, solubility and biocompatibility features. Further their exterior surface can be modified for better tumour-targeting ability. More studies, are warranted to determine the immunogenicity, biodistribution, and clearance from the body.

GENERAL PERSPECTIVE

This review discusses a few selected examples of the remarkable in vitro and in vivo studies that have been carried out in the recent past with the use of AFt and Dps in targeting and delivery of various pharmaceutical agents, natural products and imaging probes in the field of oncology.

A biodegradable multifunctional nanoplatform based on antimonene nanosheets for synergistic cancer phototherapy and dual imaging

Recently, nanomaterials have been well-studied in cancer therapy, but some of them often experience difficulties with degradation in vivo, which could cause severe damage to the human body. Among numerous biodegradable nanomaterials, antimonene nanosheets (AMNSs) are versatile, and possess photothermal and photodynamic properties and photoacoustic imaging (PAI) and drug loading ability. Herein, we employed a clearable multifunctional system. The small molecule photosensitizer IR820 and the gold nanoparticles (AuNPs) at small sizes of approximately 5 nm were loaded onto AMNSs coated with biodegradable chitosan (CS). This nanoplatform showed excellent photothermal and photodynamic properties, satisfactory degradability and photoacoustic imaging ability, good biocompatibility and effective NIR light triggered intracellular synergistic treatment. It also displayed good fluorescence imaging ability in the experiment of cell uptake. These suggested that this versatile nanoplatform was able to significantly enhance the therapeutic efficiency based on synergistic phototherapy, and could also be applied in fluorescence and photoacoustic dual imaging for integrating diagnosis and treatment.

Conjugated Organic Photothermal Films for Spatiotemporal Thermal Engineering

With the growth of photoenergy harvesting and thermal engineering, photothermal materials (PTMs) have attracted substantial interest due to their unique functions such as localized heat generation, spatiotemporal thermal controllability, invisibility, and light harvesting capabilities. In particular, π-conjugated organic PTMs show advantages over inorganic or metallic PTMs in thin film applications due to their large light absorptivity, ease of synthesis and tunability of molecular structures for realizing high NIR absorption, flexibility, and solution processability. This review is intended to provide an overview of organic PTMs, including both molecular and polymeric PTMs. A description of the photothermal (PT) effect and conversion efficiency (ηPT ) for organic films is provided. After that, the chemical structure and optical properties of organic PTMs are discussed. Finally, emerging applications of organic PT films from the perspective of spatiotemporal thermal engineering principles are illustrated.

Photodynamic Inactivation of an Endodontic Bacteria Using Diode Laser and Indocyanine Green-Loaded Nanosphere

Apical periodontitis, an inflammatory lesion causing bone resorption around the apex of teeth, is treated by eradicating infectious bacteria from the root canal. However, it has a high recurrence rate and often requires retreatment. We investigated the bactericidal effect of antimicrobial photodynamic therapy (aPDT)/photodynamic antimicrobial chemotherapy (PACT) using indocyanine green (ICG)-loaded nanospheres coated with chitosan and a diode laser on a biofilm of Enterococcus faecalis, a pathogen of refractory apical periodontitis. Biofilm of E. faecalis was cultured in a porcine infected root canal model. ICG solution was injected into the root canal, which was then irradiated with a laser (810 nm wavelength) from outside the root canal. The bactericidal effect was evaluated by colony counts and scanning electron microscopy. The result of the colony counts showed a maximum 1.89 log reduction after irradiation at 2.1 W for 5 min. The temperature rise during aPDT/PACT was confirmed to be within a safe range. Furthermore, the light energy transmittance through the root was at a peak approximately 1 min after the start of irradiation, indicating that most of the ICG in the root canal was consumed. This study shows that aPDT/PACT can suppress E. faecalis in infected root canals with high efficiency.

Incorporation of nanogels within calcite single crystals for the storage, protection and controlled release of active compounds

Nanocarriers have tremendous potential for the encapsulation, storage and delivery of active compounds. However, current formulations often employ open structures that achieve efficient loading of active agents, but that suffer undesired leakage and instability of the payloads over time. Here, a straightforward strategy that overcomes these issues is presented, in which protein nanogels are encapsulated within single crystals of calcite (CaCO3). Demonstrating our approach with bovine serum albumin (BSA) nanogels loaded with (bio)active compounds, including doxorubicin (a chemotherapeutic drug) and lysozyme (an antibacterial enzyme), we show that these nanogels can be occluded within calcite host crystals at levels of up to 45 vol%. Encapsulated within the dense mineral, the active compounds are stable against harsh conditions such as high temperature and pH, and controlled release can be triggered by a simple reduction of the pH. Comparisons with analogous systems - amorphous calcium carbonate, mesoporous vaterite (CaCO3) polycrystals, and calcite crystals containing polymer vesicles - demonstrate the superior encapsulation performance of the nanogel/calcite system. This opens the door to encapsulating a broad range of existing nanocarrier systems within single crystal hosts for the efficient storage, transport and controlled release of various active guest species.

Bioengineered Ferritin Nanocarriers for Cancer Therapy

Ferritin naturally exists in most organisms and can specifically recognize the transferrin 1 receptor (TfR1), which is generally highly expressed on various types of tumor cells. The pH dependent reversible assembling and disassembling property of ferritin renders it as a suitable candidate for encapsulating a variety of anticancer drugs and imaging probes. Ferritins external surface is chemically and genetically modifiable which can serve as attachment site for tumor specific targeting peptides or moieties. Moreover, the biological origin of these protein cages makes it a biocompatible nanocarrier that stabilizes and protects the enclosed particles from the external environment without provoking any toxic or immunogenic responses. Recent studies, further establish ferritin as a multifunctional nanocarrier for targeted cancer chemotherapy and phototherapy. In this review, we introduce the favorable characteristics of ferritin drug carriers, the specific targeted surface modification and a multifunctional nanocarriers combined chemotherapy with phototherapy for tumor treatment. Taken together, ferritin is a potential ideal base of engineered nanoparticles for tumor therapy and still needs to explore more on its way.

Cyanine Dyes for Photo-Thermal Therapy: A Comparison of Synthetic Liposomes and Natural Erythrocyte-Based Carriers

Cyanine fluorescent dyes are attractive diagnostic or therapeutic agents due to their excellent optical properties. However, in free form, their use in biological applications is limited due to the short circulation time, instability, and toxicity. Therefore, their encapsulation into nano-carriers might help overcome the above-mentioned issues. In addition to indocyanine green (ICG), which is clinically approved and therefore the most widely used fluorescent dye, we tested the structurally similar and cheaper alternative called IR-820. Both dyes were encapsulated into liposomes. However, due to the synthetic origin of liposomes, they can induce an immunogenic response. To address this challenge, we proposed to use erythrocyte membrane vesicles (EMVs) as “new era” nano-carriers for cyanine dyes. The optical properties of both dyes were investigated in different biological relevant media. Then, the temperature stability and photo-stability of dyes in free form and encapsulated into liposomes and EMVs were evaluated. Nano-carriers efficiently protected dyes from thermal degradation, as well as from photo-induced degradation. Finally, a hemotoxicity study revealed that EMVs seem less hemotoxic dye carriers than clinically approved liposomes. Herein, we showed that EMVs exhibit great potential as nano-carriers for dyes with improved stability and hemocompatibility without losing excellent optical properties.

Photosensitizer-Functionalized Nanocomposites for Light-Activated Cancer Theranostics

Photosensitizers (PSs) have received significant attention recently in cancer treatment due to its theranostic capability for imaging and phototherapy. These PSs are highly responsive to light source of a suitable wavelength for image-guided cancer therapy from generated singlet oxygen and/or thermal heat. Various organic dye PSs show tremendous attenuation of tumor cells during cancer treatment. Among them, porphyrin and chlorophyll-based ultraviolet-visible (UV-Vis) dyes are employed for photodynamic therapy (PDT) by reactive oxygen species (ROS) and free radicals generated with 400-700 nm laser lights, which have poor tissue penetration depth. To enhance the efficacy of PDT, other light sources such as red light laser and X-ray have been suggested; nonetheless, it is still a challenging task to improve the light penetration depth for deep tumor treatment. To overcome this deficiency, near infrared (NIR) (700-900 nm) PSs, indocyanine green (ICG), and its derivatives like IR780, IR806 and IR820, have been introduced for imaging and phototherapy. These NIR PSs have been used in various cancer treatment modality by combining photothermal therapy (PTT) and/or PDT with chemotherapy or immunotherapy. In this review, we will focus on the use of different PSs showing photothermal/photodynamic response to UV-Vis or NIR-Vis light. The emphasis is a comprehensive review of recent smart design of PS-loaded nanocomposites for targeted delivery of PSs in light-activated combination cancer therapy.

Biocompatible melanin based theranostic agent for in vivo detection and ablation of orthotopic micro-hepatocellular carcinoma

Early diagnosis and therapy of hepatocellular carcinoma (HCC) is critical to improve the five-year survival rates of patients. Theranostic agents synergized with photothermal ablation are expected to realize the early detection and treatment of orthotopic HCC. However, conventional metallic nanoagents are limited by their potential bio-toxicity to surrounding normal organs. Recently, endogenous biological melanin pigments have been utilized to develop nanoplatforms due to their excellent biocompatibility and degradability. Whereas, the insufficient capability of PEGylated melanin nanoparticles (PEG-MNPs) in photoacoustic (PA) imaging limits their further biomedical applications. Paradoxically, it is difficult to meet these two different requirements. Herein, a multifunctional nanoagent based on melanin (MNPs) conjugating the near-infrared (NIR) dye IR820 was successfully designed and fabricated. Encapsulation by polyethylene glycol (PEG) renders the solubility in water and allows the physical absorption of IR820 for enhanced photoacoustic (PA) performance and photothermal therapy. Besides, PEG coating on the surface of IR820-PEG-MNPs resulted in a reduction in swallowing in the reticuloendothelial system of the liver and spleen, prolonging the circulation time in the blood and increasing the accumulation in the tumor. The IR820-PEG-MNPs displayed satisfactory PA and T1-weighted magnetic resonance imaging (MRI) signals in aqueous solution as well as strong photothermal efficiency. Compared with prior injection, PA/MR signals of the tumor region were enhanced by 4.13- and 1.60-fold, respectively, which could effectively detect lesions smaller than ∼1.8 mm. Furthermore, the high photothermal conversion efficiency (40.2%) endowed the IR820-PEG-MNPs with the capability of selectively ablating tumors in orthotopic HCC mouse models under the guidance of PA/MR imaging. This work broadens the biomedical applications of melanin-based agent, which are promising for the precise diagnosis of orthotopic micro HCC and imaging guided photothermal ablation.

CD44-Targeting Oxygen Self-Sufficient Nanoparticles for Enhanced Photodynamic Therapy Against Malignant Melanoma

Objective

Nanotechnology-based photodynamic therapy (PDT) is a relatively new anti-tumor strategy. However, its efficacy is limited by the hypoxic state in the tumor microenvironment. In the present study, a poly(lactic-co-glycolic acid) (PLGA) nanoparticle that encapsulated both IR820 and catalase (CAT) was developed to enhance anti-tumor therapy.

Materials and Methods

HA-PLGA-CAT-IR820 nanoparticles (HCINPs) were fabricated via a double emulsion solvent evaporation method. Dynamic light scattering (DLS), transmission electron microscopy (TEM), laser scanning confocal microscopy, and an ultraviolet spectrophotometer were used to identify and characterize the nanoparticles. The stability of the nanoparticle was investigated by DLS via monitoring the sizes and polydispersity indexes (PDIs) in water, PBS, DMEM, and DMEM+10%FBS. Oxygen generation measurement was carried out via visualizing the oxygen bubbles with ultrasound imaging system and an optical microscope. Inverted fluorescence microscopy and flow cytometry were used to measure the uptake and targeting effect of the fluorescent-labeled nanoparticles. The live-dead method and tumor-bearing mouse models were applied to study the HCINP-induced enhanced PDT effect.

Results

The results showed that the HCINPs could selectively target melanoma cells with high expression of CD44, and generated oxygen by catalyzing H₂O₂, which increased the amount of singlet oxygen, ultimately inhibiting tumor growth significantly.

Conclusion

The present study presents a novel nanoplatform for melanoma treatment.

Minimally invasive photothermal ablation assisted by laparoscopy as an effective preoperative neoadjuvant treatment for orthotopic hepatocellular carcinoma

Nanoparticle-based photothermal ablation (PTA) has been intensively investigated recently. However, the poor biocompatibility of most PTA agents and potential long-term toxicity obstruct their clinical translation. Meanwhile, previous PTA studies are limited to surface tumors because of insufficient light penetration depth of near-infrared (NIR) light for deep abdominal tumors. Therefore, minimally invasive PTA combined with biocompatible agents may pave a promising way to treat deep orthotopic hepatocellular carcinoma (HCC). Herein, a multifunctional agent based on superparamagnetic iron oxide (SPIO) and new indocyanine green (IR820) was constructed with good biocompatibility. Outstanding fluorescence, photoacoustic and magnetic resonance imaging capabilities were observed in vitro. Additionally, in vivo results indicated that early-stage HCC (diameter less than 2 mm) could be effectively detected by this agent. Furthermore, for the first time, we developed minimally invasive laparoscopic-assisted photothermal ablation (L-A PTA) method coupled with this agent to completely ablate orthotopic HCC in nude mice model, neither recurrences nor obvious side effects were observed during the experiments. Remarkable shrinkage of primary tumor and disappearance of intrahepatic metastasis were also observed. In summary, minimally invasive L-A PTA is an effective preoperative neoadjuvant treatment for HCC.

Tumor-Microenvironment-Activatable Nanoreactor Based on a Polyprodrug for Multimodal-Imaging-Medicated Enhanced Cancer Chemo/Phototherapy

Anticancer nanomedicine-based multimodal imaging and synergistic therapy hold great promise in cancer diagnosis and therapy owing to their abilities to improve therapeutic efficiency and reduce unnecessary side effects, producing promising clinical prospects. Herein, we integrated chemotherapeutic drug camptothecin (CPT) and near-infrared-absorbing new indocyanine green (IR820) into a single system by charge interaction and obtained a tumor-microenvironment-activatable PCPT_SS/IR820 nanoreactor to perform thermal/fluorescence/photoacoustic-imaging-guided chemotherapy and photothermal therapy simultaneously. Specifically, the generated PCPT_SS/IR820 showed an excellent therapeutic agent loading content and size stability, and the trials in vitro and in vivo suggested that the smart PCPT_SS/IR820 could deeply permeate into tumor tissues due to its suitable micellar size. Upon near-infrared laser irradiation, the nanoreactor further produced a terrific synergism of chemo-photo treatment for cancer therapy. Therefore, the PCPT_SS/IR820 polyprodrug-based nanoreactor holds outstanding promise for multimodal imaging and combined dual therapy.

Improvement of Photostability and NIR Activity of Cyanine Dye through Nanohybrid Formation: Key Information from Ultrafast Dynamical Studies

Near-infrared (NIR) light harvesting has enormous importance for different potential applications in the modern era of research. Some NIR cyanine dyes such as IR820 have achieved great success in energy harvesting and cancer therapy. However, their action is limited for low photostability, considerable thermal degradation, short circulation times, and nonspecific biodistribution. Our present study is an attempt to overcome such limitations by attaching a model cyanine dye IR820 with ZnO nanoparticles. We prepared an IR820-ZnO nanohybrid and characterized it using microscopic and optical spectroscopic tools. Thermogravimetric analysis depicted greater thermal stability of the IR820-ZnO nanohybrid compared to free dye. We explored the enhancement in the photostability of IR820 upon nanohybrid formation. We detected generation of photoinduced reactive oxygen species (ROS) such as superoxide, singlet oxygen, and so forth using appropriate molecular probes. The formation of IR820-ZnO nanohybrid reduced production of photoinduced singlet oxygen. However, it revealed an alternative trend in overall ROS formation (increases total ROS) under red light illumination. To correlate the enhanced photostability of IR820 on the ZnO surface, we explored excited-state dynamical processes at the interface in nanohybrids. We illustrated the photoinduced excited-state electron-transfer process from the lowest unoccupied molecular orbital of IR820 to the conduction band of ZnO. This photoelectron-transfer process enhances the production of ROS and decreases the formation of singlet oxygen that altogether leads to improvement in photostability and overall activity. A quencher of singlet oxygen sodium azide (NaN₃) was used to further confirm the direct association of singlet oxygen generation with the photostability issue of IR820. Also, ZnO is able to deliver the dye selectively in acidic environment, which suggests its diseased site-specific targeted activity. Our results provide promising improvement for potential use of IR820 through formation of a nanohybrid that could be translated for other NIR cyanine dyes.

Dual Imaging-Guided Oxidative-Photothermal Combination Anticancer Therapeutics

Heme oxygenase-1 (HO-1) is a stress-response protein with potent cytoprotective and antioxidant activity, and its expression in cancer cells is enhanced in response to chemotherapy and radiotherapy. HO-1 is known to serve as a shield to protect cancer cells from anticancer therapy and attenuate apoptotic signals. It can be therefore reasoned that inhibition of HO-1 reduces the antioxidant level, making cancer cells more sensitive to photothermal heating. In this work, we developed dual imaging-guided oxidative-photothermal combination nanotherapeutics (OPCN) consisting of amphiphilic polymers conjugated with zinc protoporphyrin as a HO-1 inhibitor and fluorescent IR820 as a photothermal agent. A combination of OPCN and near-infrared (NIR) laser irradiation markedly increased the temperature and exerted significant toxicity through induction of apoptosis. In a mouse model of xenografts, tumors were identified by the strong fluorescence and photoacoustic signals. OPCN combined with NIR laser irradiation resulted in effective and complete thermal ablation of tumors without discernable side effects and tumor recurrence. We believe that OPCN hold tremendous translational potential for dual imaging-guided oxidative-photothermal combination anticancer therapy.

CuS@MOF-Based Well-Designed Quercetin Delivery System for Chemo-Photothermal Therapy

Quercetin (QT) is one promising candidate for the treatment of various cancers with virtually no toxic side effects. However, its anticancer effect is severely restricted by its poor bioavailability, low water solubility, and chemical instability in the neutral and alkaline medium. Herein, zeolitic imidazolate framework-8 (ZIF-8) is first reported as the multifunctional nanoplatform to the codelivery of quercetin as an anticancer agent and CuS nanoparticles as a photothermal therapy (PTT) agent for synergistic combination of chemotherapy and PTT as well as overcoming the drawbacks of quercetin. Moreover, folic acid-bovine serum albumin (FA-BSA) conjugates are applied to stabilize the CuS@ZIF-8-QT to promote the bioavailability of quercetin and realize active-targeting drug delivery. Near-infrared (NIR) fluorescent imaging demonstrated the highly increased drug accumulations of FA-BSA/CuS@ZIF-8-QT in tumors, resulting from efficient internalization via FA-receptors-mediated endocytosis. The results of in vivo and in vitro anticancer experiments demonstrate that quercetin and PTT agent can work together efficiently under NIR irradiation, thus remarkably improving the anticancer effect. Therefore, our newly designed FA-BSA/CuS@ZIF-8-QT multifunctional drug delivery system might be a promising nanoplatform for cancer treatment.

pH- and Enzyme-Sensitive IR820-Paclitaxel Conjugate Self-Assembled Nanovehicles for Near-Infrared Fluorescence Imaging-Guided Chemo-Photothermal Therapy

The short lifetime and easy quick elimination of the near-infrared (NIR) dye new indocyanine green (IR820) in the body restrict its practical application as a photothermal agent in cancer therapy. Meanwhile, the drawback of poor water solubility of the chemotherapeutic drug paclitaxel (PTX) largely restricts its clinical applications. Herein, we, for the first time, combined IR820 and PTX in an "all-in-one" fluorescence imaging-guided chemo-photothermal therapy (PTT) platform by a rational design of a novel pH- and enzyme-sensitive IR820-PTX conjugate assembly. Specifically, the IR820-PTX conjugate nanoparticles exhibit an extremely high therapeutic agent content (IR820 and PTX, 95.7%). Besides the good stability in bloodstream, the IR820-PTX nanoparticles can target tumors for high accumulation via the enhanced permeation and retention effect. Particularly, our IR820-PTX nanoparticles simultaneously solve the obstacles of PTX poor solubility and the short lifetime of IR820 for cancer therapy. The simultaneous release of the free drug and dye can efficiently kill tumor cells by the combination of PTT and chemotherapy via NIR irradiation. Furthermore, the combined therapy can be imaging-guided by measuring the NIR fluorescence imaging resulting from the IR820 component. Therefore, our rationally designed pH- and enzyme-sensitive IR820-PTX conjugate nanoparticles provide an alternative "all-in-one" option for an efficient combinational dual-therapy and imaging.

Loading IR820 Using Multifunctional Dendrimers with Enhanced Stability and Specificity

Cyanine dyes are promising candidates in biomedical applications. Although various delivery systems have been developed to enhance their properties, their dendrimer-based delivery systems are seldom investigated. Herein, amine-terminated generation 5 poly(amidoamine) (G5.NH₂) dendrimers and new indocyanine green (IR820) dyes were chosen as models to study the loading ability of dendrimers for cyanine dynes. G5.NH₂ dendrimers were pre-modified with arginine-glycine-aspartic (RGD) peptides, poly(ethylene glycol) chains, and acetyl groups to be endowed with cancer cell specificity and biocompatibility. The formed Ac-PR dendrimers were used to load IR820, followed by thorough characterization. The loaded number of IR820 was estimated to be 6.7 per dendrimer. The stability of IR820 was improved through dendrimer loading, which was proved by their UV-vis spectra under different kinds of storage conditions. In addition, the formed Ac-PR dendrimers can retain the loaded IR820 effectively. Their cytocompatibility was desirable under the studied conditions. Their cellular uptake behaviors were demonstrated to be enhanced by RGD modification, showing concentration-, co-incubation time-, and αvβ₃ integrin receptor-dependent properties, displaying a cytoplasm-location. The findings from this work demonstrated the versatile loading and delivery capacity of dendrimers for near-infrared (NIR) dyes, providing fundamental data for the development of dendrimer/NIR dye systems for biomedical applications, especially for cancer theranostic applications.

Near infrared dye-labelled polymeric micro- and nanomaterials: in vivo imaging and evaluation of their local persistence

The use of micro- and nanomaterials as carriers of therapeutic molecules can enhance the efficiency of treatments while avoiding side effects thanks to the development of controlled drug delivery systems. The binding of a dye to a drug or to a drug carrier has opened up a wide range of possibilities for an effective in vivo optical tracing of drug biodistribution by using non-invasive real-time technologies prior to their potential use as therapeutic vectors. Here, we describe the fluorescent tagging of polymeric micro- and nanomaterials based on poly(lactic-co-glycolic) acid and on the thermoresponsive poly(N-isopropylacrylamide) with the fluorescent probe IR-820 which was chemically modified for its covalent coupling to the materials. The chemical modification of the dye and the polymers yielded micro- and nanoparticulated labelled materials to be potentially used as drug depots of different therapeutic molecules. In vitro biological studies revealed their reduced cytotoxicity. A spatiotemporal in vivo micro- and nanoparticle tracking allowed the evaluation of the biodistribution of materials showing their local persistence and high biocompatibility after pathological studies. These results underline the suitability of these materials for the local, sustained, not harmful and/or on-demand drug delivery and the remarkable importance of evaluating the biodistribution of materials and tissue persistence for their use as local drug depots.

IR820 covalently linked with self-assembled polypeptide for photothermal therapy applications in cancer

Elastin-like polypeptide covalently was linked with IR820 in an aqueous environment, followed by self-assembly into nanoparticles after adding to zinc ions solution. ELP-IR820 nanoparticles significantly accumulated at the tumor site.

Hydrophobic binding peptide-conjugated hybrid lipid-mesoporous silica nanoparticles for effective chemo-photothermal therapy of pancreatic cancer

Nanoparticle-based drug delivery systems are designed to reach tumor sites based on their enhanced permeation and retention effects. However, a lack of interaction of these nanoparticles with cancer cells might lead to reduced uptake in the tumors, which might compromise the therapeutic efficacy of the system. Therefore, we developed bortezomib and IR-820-loaded hybrid-lipid mesoporous silica nanoparticles conjugated with the hydrophobic-binding peptide, cyclosporine A (CsA), and referred to them as CLMSN/BIR. Upon reaching the tumor site, CsA interacts hydrophobically with the cancer cell membranes to allow effective uptake of the nanoparticles. Nanoparticles ∼160 nm in size were prepared and the stability of IR-820 significantly improved. High cellular uptake of the nanoparticles was evident with pronounced apoptotic effects in PANC-1 and MIA PaCa-2 cells that were mediated by the chemotherapeutic effect of bortezomib and the photothermal and reactive oxygen species generation effects of IR-820. An in vivo biodistribution study indicated there was high accumulation in the tumor with an enhanced photothermal effect in PANC-1 xenograft mouse tumors. Furthermore, enhanced antitumor effects in PANC-1 xenograft tumors were observed with minimal toxicity induction in the organs of mice. Cumulatively, these results indicated the promising effects of CLMSN/BIR for effective chemo-phototherapy of pancreatic cancers.

Polyethylene glycol modified ORMOSIL theranostic nanoparticles for triggered doxorubicin release and deep drug delivery into ovarian cancer spheroids

A novel pegylated multifunctional probe of Ormosil nanoparticles (PEGCDSIR820) loaded with Near Infrared dye (NIR; IR820) and a chemotherapeutic drug, Doxorubicin (DOX) was developed for cancer theranostic applications. PEGCDSIR820 nanoparticles had an average diameter of 58.2±3.1nm, zeta potential of -6.9±0.1mV in cell culture media and stability against aggregation in physiological buffers. The encapsulation efficiency of DOX was 65.0±3.0%, and that of IR820 was 76.0±2.1%. PEGCDSIR820 showed no cytotoxicity in ovarian cancer cells (Skov-3). The cytotoxicity markedly increased when Skov-3 cells incubated with PEGCDSIR820 particles were exposed to 808nm laser due to the combination of adjuvant hyperthermia (43°C) and enhanced DOX release. Exposure to laser enhanced the release of DOX, 45% of DOX release was observed in 3h compared to 23% without laser exposure. Confocal imaging in Skov-3 cells showed that the combination of hyperthermia due to NIR exposure and release of DOX caused cell necrosis. Furthermore, in spheroids exposed to NIR laser penetration of DOX was deeper compared to the absence of laser exposure. Skov-3 spheroids incubated with pegylated nanoparticles for 24h and exposed to laser showed 94% reduction in cell viability. Encapsulation of IR820 in PEGCDSIR820 increased the in-vivo elimination half-life to 41.0±7.2h from 30.5±0.5h of free IR820.

Cyanine based Nanoprobes for Cancer Theranostics

Cyanine dyes are greatly accredited in the development of non-invasive therapy that can "see" and "treat" tumor cells via imaging, photothermal and photodynamic treatment. However, these dyes suffer from poor pharmacokinetics inducing severe toxicity to normal cells, insufficient accumulation in tumor regions and rapid photobleaching when delivered in free forms. Nanoparticles engineered to encapsulate these compounds and delivering them into tumor regions have increased rapidly, however, so far, these nanoparticles (NPs) have not proved to be so effective to circumvent existing challenges. Newly designed multifunctional smart nanocarriers that can improve phototherapeutic properties of these dyes, co-encapsulate multiple potent therapeutic compounds, and simultaneously overcome limitations related to tumor recurrence, metastases, limited intracellular uptake, and tumor hypoxia have potential to revolutionize modern paradigm of cancer therapy. Such cyanine based multifunctional nanocarriers integrating imaging and therapy in a single platform can effectively produce better clinical outcomes in cancer treatment. This review briefly summarizes recent advancements of cyanine nanoprobes that are currently used as imaging/phototherapeutic agents in unimodal/bimodal/trimodal cancer theranostics. Finally, we conclude this review by addressing challenges of pre-existing therapeutic systems and designs adopted to overcome them with a brief insight assimilating future perspective of emerging cyanine-based NPs in cancer theranostics.

Fibrin-Targeted and H2O2-Responsive Nanoparticles as a Theranostics for Thrombosed Vessels

A thrombus (blood clot) is formed in injured vessels to maintain the integrity of vasculature. However, obstruction of blood vessels by thrombosis slows blood flow, leading to death of tissues fed by the artery and is the main culprit of various life-threatening cardiovascular diseases. Herein, we report a rationally designed nanomedicine that could specifically image obstructed vessels and inhibit thrombus formation. On the basis of the physicochemical and biological characteristics of thrombi such as an abundance of fibrin and an elevated level of hydrogen peroxide (H₂O₂), we developed a fibrin-targeted imaging and antithrombotic nanomedicine, termed FTIAN, as a theranostic system for obstructive thrombosis. FTIAN inhibited the generation of H₂O₂ and suppressed the expression of tumor necrosis factor-alpha (TNF-α) and soluble CD40 ligand (sCD40L) in activated platelets, demonstrating its intrinsic antioxidant, anti-inflammatory, and antiplatelet activity. In a mouse model of ferric chloride (FeCl₃)-induced carotid thrombosis, FTIAN specifically targeted the obstructive thrombus and significantly enhanced the fluorescence/photoacoustic signal. When loaded with the antiplatelet drug tirofiban, FTIAN remarkably suppressed thrombus formation. Given its thrombus-specific imaging along with excellent therapeutic activities, FTIAN offers tremendous translational potential as a nanotheranostic agent for obstructive thrombosis.

Rational Design of Metal Organic Framework Nanocarrier-Based Codelivery System of Doxorubicin Hydrochloride/Verapamil Hydrochloride for Overcoming Multidrug Resistance with Efficient Targeted Cancer Therapy

Conventional organic and inorganic drug nanocarriers suffer from serious drawbacks such as low drug-storage capacity and uncontrolled release. Moreover, multidrug resistance (MDR) has been one of the primary causes leading to chemotherapy failure for cancers. The main reason for MDR is the overexpressed active efflux transporters such as P-glycoprotein. Here, zeolitic imidazolate framework ZIF-8, as one of the biocompatible metal organic frameworks (MOFs), is reported for the first time as the multidrug carrier to realizing the efficient codelivery of verapamil hydrochloride (VER) as the P-glycoprotein inhibitor as well as doxorubicin hydrochloride (DOX) as an anticancer drug to overcome the MDR in addition to realize the active targeted ability for an efficient anticancer effect. Uniform ZIF-8 nanoparticles encapsulating DOX and VER are achieved by a facile one-pot process, in which the VER is used to overcome the multidrug resistance. Furthermore, methoxy poly(ethylene glycol)-folate (PEG-FA) is used to stabilize the (DOX+VER)@ZIF-8 to realize prolonged circulations and an active targeting drug delivery. In particular, the ZIF-8 exhibits high drug loading content up to ∼40.9% with a pH-triggered release behavior. Importantly, the PEG-FA/(DOX+VER)@ZIF-8 shows enhanced therapeutic efficiencies with much safety compared with the direct administration of free DOX both in vitro and in vivo. Near infrared fluorescent (NIRF) imaging indicates that the PEG-FA/(DOX+VER)@ZIF-8 can increase the drug accumulations in tumors for targeted cancer therapy. Therefore, the PEG-FA/(DOX+VER)@ZIF-8 multidrug delivery system can be used as a promising efficient formulation in reversing the multidrug resistance for targeted cancer therapy.