The synergistic effect of folate and RGD dual ligand of nanographene oxide on tumor targeting and photothermal therapy in vivo

Development of dual-crosslinked Pluronic F127/Chitosan injectable hydrogels incorporating graphene nanosystems for breast cancer photothermal therapy and antibacterial applications

Nanomaterials with responsiveness to near-infrared light can mediate the photoablation of cancer cells with an exceptional spatio-temporal resolution. However, the therapeutic outcome of this modality is limited by the nanostructures' poor tumor uptake. To address this bottleneck, it is appealing to develop injectable in situ forming hydrogels due to their capacity to perform a tumor-confined delivery of the nanomaterials with minimal off-target leakage. In particular, injectable in situ forming hydrogels based on Pluronic F127 have been emerging due to their FDA-approval status, biocompatibility, and thermosensitive sol-gel transition. Nevertheless, the application of Pluronic F127 hydrogels has been limited due to their fast dissociation in aqueous media. Such limitation may be addressed by combining the thermoresponsive sol-gel transition of Pluronic F127 with other polymers with crosslinking capabilities. In this work, a novel dual-crosslinked injectable in situ forming hydrogel based on Pluronic F127 (thermosensitive gelation) and Chitosan (ionotropic gelation in the presence of NaHCO3), loaded with Dopamine-reduced graphene oxide (DOPA-rGO; photothermal nanoagent), was developed for application in breast cancer photothermal therapy. The dual-crosslinked hydrogel incorporating DOPA-rGO showed a good injectability (through 21 G needles), in situ gelation capacity and cytocompatibility (viability > 73 %). As importantly, the dual-crosslinking improved the hydrogel's porosity and prevented its premature degradation. After irradiation with near-infrared light, the dual-crosslinked hydrogel incorporating DOPA-rGO produced a photothermal heating (ΔT ≈ 22 °C) that reduced the breast cancer cells' viability to just 32 %. In addition, this formulation also demonstrated a good antibacterial activity by reducing the viability of S. aureus and E. coli to 24 and 33 %, respectively. Overall, the dual-crosslinked hydrogel incorporating DOPA-rGO is a promising macroscale technology for breast cancer photothermal therapy and antimicrobial applications.

Dual receptor specific nanoparticles targeting EGFR and PD-L1 for enhanced delivery of docetaxel in cancer therapy

Dual-receptor targeted (DRT) nanoparticles which contain two distinct targeting agents may exhibit higher cell selectivity, cellular uptake, and cytotoxicity toward cancer cells than single-ligand targeted nanoparticle systems without additional functionality. The purpose of this study is to prepare DRT poly(lactic-co-glycolic acid) (PLGA) nanoparticles for targeting the delivery of docetaxel (DTX) to the EGFR and PD-L1 receptor positive cancer cells such as human glioblastoma multiform (U87-MG) and human non-small cell lung cancer (A549) cell lines. Anti-EGFR and anti-PD-L1 antibody were decorated on DTX loaded PLGA nanoparticles to prepare DRT-DTX-PLGA via. single emulsion solvent evaporation method. Physicochemical characterizations of DRT-DTX-PLGA, such as particle size, zeta-potential, morphology, and in vitro DTX release were also evaluated. The average particle size of DRT-DTX-PLGA was 124.2 ± 1.1 nm with spherical and smooth morphology. In the cellular uptake study, the DRT-DTX-PLGA endocytosed by the U87-MG and A549 cells was single ligand targeting nanoparticle. From the in vitro cell cytotoxicity, and apoptosis studies, we reported that DRT-DTX-PLGA exhibited high cytotoxicity and enhanced the apoptotic cell compared to the single ligand-targeted nanoparticle. The dual receptor mediated endocytosis of DRT-DTX-PLGA showed a high binding affinity effect that leads to high intracellular DTX concentration and exhibited high cytotoxic properties. Thus, DRT nanoparticles have the potential to improve cancer therapy by providing selectivity over single-ligand-targeted nanoparticles.

Novel Application of NIR-I-Absorbing Quinoidal Conjugated Polymer as a Photothermal Therapeutic Agent

Conjugated polymer nanoparticles (CP NPs) that could absorb the first near-infrared (NIR-I) window have emerged as highly desirable therapeutic nanomaterials. Here, a quinoidal-conjugated polymer (QCP), termed PQ, was developed as a novel class of therapeutic agents for photothermal therapy (PTT). Owing to its intrinsic quinoid structure, PQ exhibits molecular planarity and π-electron overlap along the conjugated backbone, endowing it with a narrow band gap, NIR-I absorption, and diradical features. The obtained PQ was coated with a poly(ethylene glycol) (PEG) moiety, affording nanosized and water-dispersed PQ nanoparticles (PQ NPs), which consequently show a high photothermal conversion efficiency (PCE) of 63.2%, good photostability, and apparent therapeutic efficacy for both in vitro and in vivo PTTs under an 808 nm laser irradiation. This study demonstrates that QCPs are promising active agents for noninvasive anticancer therapy using NIR-I light.

Current Principles, Challenges, and New Metrics in pH-Responsive Drug Delivery Systems for Systemic Cancer Therapy

The paradigm of drug delivery via particulate formulations is one of the leading ideas that enable overcoming limitations of traditional chemotherapeutic agents. The trend toward more complex multifunctional drug carriers is well-traced in the literature. Nowadays, the prospectiveness of stimuli-responsive systems capable of controlled cargo release in the lesion nidus is widely accepted. Both endogenous and exogenous stimuli are employed for this purpose; however, endogenous pH is the most common trigger. Unfortunately, scientists encounter multiple challenges on the way to the implementation of this idea related to the vehicles' accumulation in off-target tissues, their immunogenicity, the complexity of drug delivery to intracellular targets, and finally, the difficulties in the fabrication of carriers matching all imposed requirements. Here, we discuss fundamental strategies for pH-responsive drug delivery, as well as limitations related to such carriers' application, and reveal the main problems, weaknesses, and reasons for poor clinical results. Moreover, we attempted to formulate the profiles of an "ideal" drug carrier in the frame of different strategies drawing on the example of metal-comprising materials and considered recently published studies through the lens of these profiles. We believe that this approach will facilitate the formulation of the main challenges facing researchers and the identification of the most promising trends in technology development.

Astatine-211-Labeled Gold Nanoparticles for Targeted Alpha-Particle Therapy via Intravenous Injection

Alpha-particle radiotherapy has gained considerable attention owing to its potent anti-cancer effect. ²¹¹At, with a relatively short half-life of 7.2 h, emits an alpha particle within a few cell diameters with high kinetic energy, which damages cancer cells with high biological effectiveness. In this study, we investigated the intravenous injection of ²¹¹At-labeled gold nanoparticles (AuNPs) for targeted alpha-particle therapy (TAT). Different kinds of surface-modified gold nanoparticles can be labeled with ²¹¹At in high radiochemical yield in 5 min, and no purification is necessary. The in vivo biodistribution results showed the accumulation of 5 nm ²¹¹At-AuNPs@mPEG at 2.25% injection dose per gram (% ID/g) in tumors within 3 h via the enhanced permeability and retention (EPR) effect. Additionally, we observed a long retention time in tumor tissues within 24 h. This is the first study to demonstrate the anti-tumor efficacy of 5 nm ²¹¹At-AuNPs@mPEG that can significantly suppress tumor growth in a pancreatic cancer model via intravenous administration. AuNPs are satisfactory carriers for ²¹¹At delivery, due to simple and efficient synthesis processes and high stability. The intravenous administration of 5 nm ²¹¹At-AuNPs@mPEG has a significant anti-tumor effect. This study provides a new framework for designing nanoparticles suitable for targeted alpha-particle therapy via intravenous injection.

Mono and Multiple Tumor-Targeting Ligand-Coated Ultrasmall Gadolinium Oxide Nanoparticles: Enhanced Tumor Imaging and Blood Circulation

Hydrophilic and biocompatible PAA-coated ultrasmall Gd₂O₃ nanoparticles (d_avg = 1.7 nm) were synthesized and conjugated with tumor-targeting ligands, i.e., cyclic arginylglycylaspartic acid (cRGD) and/or folic acid (FA). FA-PAA-Gd₂O₃ and cRGD/FA-PAA-Gd₂O₃ nanoparticles were successfully applied in U87MG tumor-bearing mice for tumor imaging using T₁ magnetic resonance imaging (MRI). cRGD/FA-PAA-Gd₂O₃ nanoparticles with multiple tumor-targeting ligands exhibited higher contrasts at the tumor site than FA-PAA-Gd₂O₃ nanoparticles with mono tumor-targeting ligands. In addition, the cRGD/FA-PAA-Gd₂O₃ nanoparticles exhibited higher contrasts in all organs, especially the aorta, compared with those of the FA-PAA-Gd₂O₃ nanoparticles, because of the blood cell hitchhiking effect of cRGD in the cRGD/FA-PAA-Gd₂O₃ nanoparticles, which prolonged their circulation in the blood.

Cascade Drug Delivery through Tumor Barriers of Pancreatic Cancer via Ultrasound in Combination with Functional Microbubbles

The abundant desmoplastic stroma and the lack of sufficient targets on pancreatic cancer cells render poor drug penetration and cellular uptake, which significantly compromise the chemotherapy efficacy. Herein, we reported a three-step cascade delivery strategy for selective delivery of paclitaxel (PTX) to achieve a targeted therapy for pancreatic cancer. cRGD and cCLT1 peptides, which could target the integrin and fibronectin, respectively, overexpressed in pancreatic cancer cells and stroma, were decorated on PTX-loaded microbubbles, resulting in the formation of dual-targeting PTX-RCMBs. In this strategy, ultrasound in combination with PTX-RCMBs first enhanced the permeability of tumor vessels via cavitation effects and simultaneously helped the generated PTX-RCNPs penetrate into the stroma. Then, the cCLT1 peptide modified on PTX-RCNPs selectively bound the fibronectin highly expressed in the stroma and later targeted the integrin (α5β1) on the cell surface. Finally, another targeting cRGD peptide modified on PTX-RCNPs would further promote PTX uptake via targeting the integrin (αvβ3) on the cell surface. This strategy significantly increased the delivery of PTX into tumor tissues. Moreover, the in vivo effective accumulation of PTX was monitored by ultrasound and fluorescence bimodal imaging. The tumor growth inhibition was investigated on subcutaneous tumor mouse models with 89.8% growth inhibition rate during 21 days of treatment, showing great potential for improving pancreatic cancer therapy.

Gadolinium Neutron Capture Therapy (GdNCT) Agents from Molecular to Nano: Current Status and Perspectives

157Gd (natural abundance = 15.7%) has the highest thermal neutron capture cross section (σ) of 254,000 barns (1 barn = 10-28 m2) among stable (nonradioactive) isotopes in the periodic table. Another stable isotope, 155Gd (natural abundance = 14.8%), also has a high σ value of 60,700 barns. These σ values are higher than that of 10B (3840 barns, natural abundance = 19.9%), which is currently used as a neutron-absorbing isotope for boron neutron capture therapy agents. Energetic particles such as electrons and γ-rays emitted from Gd-isotopes after neutron beam absorption kill cancer cells by damaging DNAs inside cancer-cell nuclei without damaging normal cells if Gd-chemicals are positioned in cancer cells. To date, various Gd-chemicals such as commercial Gd-chelates used as magnetic resonance imaging contrast agents, modified Gd-chelates, nanocomposites containing Gd-chelates, fullerenes containing Gd, and solid-state Gd-nanoparticles have been investigated as gadolinium neutron capture therapy (GdNCT) agents. All GdNCT agents had exhibited cancer-cell killing effects, and the degree of the effects depended on the GdNCT agents used. This confirms that GdNCT is a promising cancer therapeutic technique. However, the commercial Gd-chelates were observed to be inadequate in clinical use because of their low accumulation in cancer cells due to their extracellular and noncancer targeting properties and rapid excretion. The other GdNCT agents exhibited higher accumulation in cancer cells, compared to Gd-chelates; consequently, they demonstrated higher cancer-cell killing effects. However, they still displayed limitations such as poor specificity to cancer cells. Therefore, continuous efforts should be made to synthesize GdNCT agents suitable in clinical applications. Herein, the principle of GdNCT, current status of GdNCT agents, and general design strategy for GdNCT agents in clinical use are discussed and reviewed.

Getting to the Core of It All: Nanocapsules to Mitigate Infusion Reactions Can Promote Hemostasis and Be a Platform for Intravenous Therapies

One of the significant challenges to translation of intravenously administered nanomaterials has been complement-mediated infusion reactions which can be lethal. Slow infusions can reduce infusion reactions, but slow infusions are not always possible in applications like controlling bleeding following trauma. Thus, avoiding complement activation and infusion responses is essential to manage bleeding. We identified nanocapsules based on polyurethane as candidates that did not activate C5a and explored their PEGylation and functionalization with the GRGDS peptide to create a new class of hemostatic nanomaterials. Using the clinically relevant rotational thromboelastography (ROTEM), we determined that nanocapsules promote faster clotting than controls and maintain the maximum clot firmness, which is critical for reducing bleeding. Excitingly, these polyurethane-based nanocapsules did not activate complement or the major pro-inflammatory cytokines. This work provides critical evidence for the role of modulating the core material in developing safer nanomedicines for intravenous applications.

CD47-mediated DTIC-loaded chitosan oligosaccharide-grafted nGO for synergistic chemo-photothermal therapy against malignant melanoma

Nano-graphene oxide (nGO), an effective drug nanocarrier, is used for simultaneous photothermal therapy (PTT) and near-infrared fluorescence imaging. Dacarbazine (DTIC) is used in the treatment of melanoma with limited clinical efficacy. PTT shows promise in the treatment of skin cancer. Herein, chitosan oligosaccharide (COS)-grafted nGO was further modified with CD47 antibody, and loaded DTIC was prepared using a versatile nanoplatform (nGO-COS-CD47/DTIC) for the treatment of melanoma as a synergistic targeted chemo-photothermal therapy. The in vitro results demonstrated that nGO-COS-CD47/DTIC nanocarriers have excellent biocompatibility, photothermal conversion efficiency, high targeting efficiency, fast drug release under NIR irradiation, and tumor cell killing efficiency. Notably, nGO-COS-CD47/DTIC plus NIR irradiation significantly promoted early cell apoptosis through the mitochondrial apoptosis pathway and exhibited a significant joint function of antitumor efficacy. The demonstrated nGO-COS-CD47/DTIC can provide a highly efficient malignant melanoma therapy using this multifunctional intelligent nanoplatform.

The Use of Alternative Strategies for Enhanced Nanoparticle Delivery to Solid Tumors

Nanomaterial (NM) delivery to solid tumors has been the focus of intense research for over a decade. Classically, scientists have tried to improve NM delivery by employing passive or active targeting strategies, making use of the so-called enhanced permeability and retention (EPR) effect. This phenomenon is made possible due to the leaky tumor vasculature through which NMs can leave the bloodstream, traverse through the gaps in the endothelial lining of the vessels, and enter the tumor. Recent studies have shown that despite many efforts to employ the EPR effect, this process remains very poor. Furthermore, the role of the EPR effect has been called into question, where it has been suggested that NMs enter the tumor via active mechanisms and not through the endothelial gaps. In this review, we provide a short overview of the EPR and mechanisms to enhance it, after which we focus on alternative delivery strategies that do not solely rely on EPR in itself but can offer interesting pharmacological, physical, and biological solutions for enhanced delivery. We discuss the strengths and shortcomings of these different strategies and suggest combinatorial approaches as the ideal path forward.

Biomedical nanoparticle design: What we can learn from viruses

Viruses are nanomaterials with a number of properties that surpass those of many synthetic nanoparticles (NPs) for biomedical applications. They possess a rigorously ordered structure, come in a variety of shapes, and present unique surface elements, such as spikes. These attributes facilitate propitious biodistribution, the crossing of complex biological barriers and a minutely coordinated interaction with cells. Due to the orchestrated sequence of interactions of their stringently arranged particle corona with cellular surface receptors they effectively identify and infect their host cells with utmost specificity, while evading the immune system at the same time. Furthermore, their efficacy is enhanced by their response to stimuli and the ability to spread from cell to cell. Over the years, great efforts have been made to mimic distinct viral traits to improve biomedical nanomaterial performance. However, a closer look at the literature reveals that no comprehensive evaluation of the benefit of virus-mimetic material design on the targeting efficiency of nanomaterials exists. In this review we, therefore, elucidate the impact that viral properties had on fundamental advances in outfitting nanomaterials with the ability to interact specifically with their target cells. We give a comprehensive overview of the diverse design strategies and identify critical steps on the way to reducing them to practice. More so, we discuss the advantages and future perspectives of a virus-mimetic nanomaterial design and try to elucidate if viral mimicry holds the key for better NP targeting.

Nanoparticles for In Vivo Lifetime Multiplexed Imaging

Lifetime multiplexed imaging refers to the simultaneous labeling of different structures with fluorescent probes that present identical photoluminescence spectra and distinct fluorescence lifetimes. This technique allows extracting quantitative information from multichannel in vivo fluorescence imaging. In vivo lifetime multiplexed imaging requires fluorophores with excitation and emission bands in the near-infrared (NIR) and tunable fluorescence lifetimes, plus an imaging system capable of time-resolved image acquisition and analysis.

The Synergistic Effect of Hyperthermia and Chemotherapy in Magnetite Nanomedicine-Based Lung Cancer Treatment

Background

Lung cancer is the leading cause of cancer patient death in the world. There are many treatment options for lung cancer, including surgery, radiation therapy, chemotherapy, targeted therapy, and combined therapy. Despite significant progress has been made in the diagnosis and treatment of lung cancer during the past few decades, the prognosis is still unsatisfactory.

Purpose

To resolve the problem of chemotherapy failure, we developed a magnetite-based nanomedicine for chemotherapy acting synergistically with loco-regional hyperthermia.

Methods

The targeting carrier consisted of a complex of superparamagnetic iron oxide (SPIO) and poly(sodium styrene sulfonate) (PSS) at the core and a layer-by-layer shell with cisplatin (CDDP), together with methotrexate – human serum albumin conjugate (MTX−HSA conjugate) for lung cancer-specific targeting, referred to hereafter as SPIO@PSS/CDDP/HSA−MTX nanoparticles (NPs).

Results

SPIO@PSS/CDDP/HSA−MTX NPs had good biocompatibility and stability in physiological solutions. Furthermore, SPIO@PSS/CDDP/HSA−MTX NPs exhibited a higher temperature increase rate than SPIO nanoparticles under irradiation by a radiofrequency (RF) generator. Therefore, SPIO@PSS/CDDP/HSA−MTX NPs could be used as a hyperthermia inducer under RF exposure after nanoparticles preferentially targeted and then accumulated at tumor sites. In addition, SPIO@PSS/CDDP/HSA−MTX NPs were developed to be used during combined chemotherapy and hyperthermia therapy, exhibiting a synergistic anticancer effect better than the effect of monotherapy.

Conclusion

Both in vitro and in vivo results suggest that the designed SPIO@PSS/CDDP/HSA−MTX NPs are a powerful candidate nanoplatform for future antitumor treatment strategies.

Adenovirus-Mimetic Nanoparticles: Sequential Ligand-Receptor Interplay as a Universal Tool for Enhanced In Vitro/In Vivo Cell Identification

Viral infection patterns often rely on precisely coordinated sequences of distinct ligand-receptor interactions, leading in many cases to an outstanding target cell specificity. A successful mimicry of viral targeting strategies to create more site-specific nanoparticles (NPs) would therefore require particle-cell interactions to also be adequately controllable. In the present study, hetero-multivalent block-copolymer NPs present their attached ligands in a sterically controlled manner to create a sequential NP-cell interaction similar to the cell infiltration strategy of human adenovirus type 2. Targeting renal mesangial cells, particles therefore initially bind angiotensin II receptor type 1 (AT1r) on the cell surface via a structurally flexible AT1r antagonist. After a mandatory spatial approach, particle endocytosis is realized via binding of immobile α_Vβ₃ integrins with a previously concealed secondary ligand, thereby creating a stepwise particle-cell interplay of primary NP attachment and subsequent uptake. Manufactured adenovirus-mimetic NPs show great avidity for both target motifs in vitro, leading to a substantial binding as well as subsequent cell uptake into target mesangial cells. Additionally, steric shielding of secondary ligand visibility leads to a highly controllable, sequential ligand-receptor interaction, whereby hetero-functional NPs activate mesangial cell surface integrins only after a successful prior binding to the AT1r. This stepwise cell identification significantly enhances mesangial cell specificity in co-culture assays with different off-target cells. Additionally, described NPs display excellent in vivo robustness by efficiently accumulating in the mesangium upon injection, thereby opening new paths for possible drug delivery applications.

Dual-Targeting Nanoparticle-Mediated Gene Therapy Strategy for Hepatocellular Carcinoma by Delivering Small Interfering RNA

As a gene therapy strategy, RNA interference (RNAi) offers tremendous tumor therapy potential. However, its therapeutic efficacy is restricted by its inferior ability for targeted delivery and cellular uptake of small interfering RNA (siRNA). This study sought to develop a dual-ligand nanoparticle (NP) system loaded with siRNA to promote targeted delivery and therapeutic efficacy. We synthesized a dual receptor-targeted chitosan nanosystem (GCGA), whose target function was controlled by the ligands of galactose of lactobionic acid (LA) and glycyrrhetinic acid (GA). By loading siPAK1, an siRNA targeting P21-activated kinase 1 (PAK1), a molecular-targeted therapeutic dual-ligand NP (GCGA-siPAK1) was established. We investigated the synergistic effect of these two targeting units in hepatocellular carcinoma (HCC). In particular, GCGA-siPAK1 enhanced the NP targeting ability and promoted siPAK1 cell uptake. Subsequently, dramatic decreases in cell proliferation, invasion, and migration, with an apparent increase in cell apoptosis, were observed in treated cells. Furthermore, this dual-ligand NP gene delivery system demonstrated significant anti-tumor effects in tumor-bearing mice. Finally, we illuminated the molecular mechanism, whereby GCGA-siPAK1 promotes endogenous cell apoptosis through the PAK1/MEK/ERK pathway. Thus, the dual-target property effectively promotes the HCC therapeutic effect and provides a promising gene therapy strategy for clinical applications.

Graphene family nanomaterials for application in cancer combination photothermal therapy

Combining hyperthermia with other therapies holds a great potential for improving cancer treatment. In this approach, the increase in the body temperature can exert a therapeutic effect on cells and/or enhance the effectiveness of anticancer agents. However, the conventional methodologies available to induce hyperthermia cannot confine a high temperature increase to the tumor-site while maintaining healthy tissues unexposed and ensuring minimal invasiveness. To overcome these limitations, combination photothermal therapy (PTT) mediated by graphene family nanomaterials (GFN) has been showing promising results. Such is owed to the ability of GFN to accumulate at the tumor site and convert near infrared light into heat, enabling a hyperthermia with a high spatial-temporal resolution. Furthermore, GFN can also incorporate different therapeutic agents on their structure for delivery purposes to cancer cells. In this way, the combination PTT mediated by GFN can result in an improved therapeutic effect. In this review, the combination of GFN mediated PTT with chemo-, photodynamic-, gene-, radio-, and immuno-therapies is examined. Furthermore, the main parameters that influence these types of combination approaches are also analyzed, with emphasis on the photothermal potential of GFN and on the vascular and cellular effects produced by the temperature increase mediated by GFN.

Advances in nanomaterials for photodynamic therapy applications: Status and challenges

Photodynamic therapy (PDT), as a non-invasive therapeutic modality that is alternative to radiotherapy and chemotherapy, is extensively investigated for cancer treatments. Although conventional organic photosensitizers (PSs) are still widely used and have achieved great progresses in PDT, the disadvantages such as hydrophobicity, poor stability within PDT environment and low cell/tissue specificity largely limit their clinical applications. Consequently, nano-agents with promising physicochemical and optical properties have emerged as an attractive alternative to overcome these drawbacks of traditional PSs. Herein, the up-to-date advances in the fabrication and fascinating applications of various nanomaterials in PDT have been summarized, including various types of nanoparticles, carbon-based nanomaterials, and two-dimensional nanomaterials, etc. In addition, the current challenges for the clinical use of PDT, and the corresponding strategies to address these issues, as well as future perspectives on further improvement of PDT have also been discussed.

A sequential targeting nanoplatform for anaplastic thyroid carcinoma theranostics

Effective accumulation of nanoparticles (NPs) in tumor regions is one of the major motivations in nanotechnology research and that the establishment of an efficient targeting nanoplatform for the treatment of malignant tumors is urgently needed for theranostic applications. In this study, we engineered multifunctional sequential targeting NPs for achieving synergistic antiangiogenic photothermal therapy (PTT) and multimodal imaging-guided diagnosis for anaplastic thyroid carcinoma (ATC) theranostics. Antibody bevacizumab with an affinity towards vascular endothelial growth factor (VEGF) on the tumor cell surface was conjugated onto the surface of polymer NPs for VEGF targeting and antiangiogenic therapy. Encapsulated IR825 was employed as a photothermal agent (PTA) with a mitochondrial targeting capability, which further cascades NPs into mitochondria to enhance hyperthermic efficiency in the ablation of tumor cells. Importantly, the combination of bevacizumab and IR825 in a single nanosystem achieved desirable accumulations of NPs and that sequential targeted PTT combined with antiangiogenesis significantly promoted the therapeutic efficiency in eradicating tumors by near-infrared (NIR) laser irradiation. Furthermore, these NPs are extraordinary contrast agents for photoacoustic, ultrasound and fluorescence imaging applications, providing multimodal imaging capabilities for therapeutic monitoring and a precise diagnosis. Therefore, this multifunctional nanoplatform provides a promising theranostic strategy for extremely malignant ATC. STATEMENT OF SIGNIFICANCE: Anaplastic thyroid carcinoma (ATC), with extremely aggressive behavior, lacks a satisfactory therapeutic method and a comprehensive early diagnostic strategy. Herein, we successfully synthesized a sequential targeting nanoplatform (IR825@Bev-PLGA-PFP NPs) with theranostic function, which specifically binds to VEGF on the tumor cell surface and further cascades into mitochondria to achieve effective accumulation of NPs in the tumor regions. As a result, it solves the urgent demand for ATC detection and therapy. By breaking the limitation of traditional target, such as low efficacy and frequent recurrence as the results of low accumulation, sequential targeting combined with synergistic antiangiogenic PTT completely eradicates tumors without any residual tissue and side effect. Therefore, this strategy paves a solid way for further investigation in the theranostic progressing of ATC.

Dually Active Targeting Nanomedicines Based on a Direct Conjugate of Two Purely Natural Ligands for Potent Chemotherapy of Ovarian Tumors

Actively targeted nanomedicines have promised to revolutionize cancer treatment; however, their clinical translation has been limited by either low targetability, use of unsafe materials, or tedious fabrication. Here, we developed CD44 and folate receptor (FR) dually targeted nanoparticulate doxorubicin (HA/FA-NP-DOX) based on a direct conjugate of two purely natural ligands, hyaluronic acid and folic acid (FA), for safe, highly specific, and potent treatment of ovarian tumors in vivo. HA/FA-NP-DOX had a small size and high DOX loading, wherein the particle size decreased from 115, 93, to 89 nm with increasing degree of substitution of FA from 6.4, 8.5, to 11.1, while increased from 80, 93, to 103 nm with increasing DOX loading from 15.0, 23.1, to 31.4 wt %. Interestingly, HA/FA-NP-DOX exhibited excellent lyophilization redispersibility and long-term storage stability with negligible drug leakage while it released 91% of DOX in 48 h at pH 5.0. Cellular studies corroborated that HA/FA-NP-DOX possessed high selectivity to both CD44 and FR, resulting in strong killing of CD44- and FR-positive SKOV-3 ovarian cancer cells while low toxicity against CD44- and FR-negative L929 fibroblast cells. In vivo studies revealed a long elimination half-life of 5.6 h, an elevated tumor accumulation of 12.0% ID/g, and an effective inhibition of the SKOV-3 ovarian tumor for HA/FA-NP-DOX, leading to significant survival benefits over free DOX·HCl and phosphate-buffered saline controls. These dually targeted nanomedicines are simple and safe, providing a potentially translatable treatment for CD44- and FR-positive malignancies.

Biodistribution and biocompatibility of glycyrrhetinic acid and galactose-modified chitosan nanoparticles as a novel targeting vehicle for hepatocellular carcinoma

Aim: The dual-ligand glycyrrhetinic acid and galactose-modified chitosan nanoparticles were designed to further improve the targeting capability to hepatocellular carcinoma (HCC). Materials & methods: The dual-ligand glycyrrhetinic acid and galactose-modified chitosan nanoparticles were fabricated by using ionic gelation method and their characteristics have been measured. Furthermore, the biodistribution and biocompatibility of this targeting vehicle were investigated in vitro and in vivo, respectively. Results: The targeting vehicle was specifically internalized into hepatoma cells in vitro and accumulated into tumor tissue in vivo with high efficacy. Moreover, the vehicle did not induce inflammation reaction and affect morphologies and organ functions. Conclusion: The targeting accumulation in HCC tissue and great biocompatibility of the dual-ligand modified chitosan nanoparticles highlight the potential of delivering anticancer agents into HCC cells.

Targeting Integrins in Cancer Nanomedicine: Applications in Cancer Diagnosis and Therapy

Due to advancements in nanotechnology, the application of nanosized materials (nanomaterials) in cancer diagnostics and therapeutics has become a leading area in cancer research. The decoration of nanomaterial surfaces with biological ligands is a major strategy for directing the actions of nanomaterials specifically to cancer cells. These ligands can bind to specific receptors on the cell surface and enable nanomaterials to actively target cancer cells. Integrins are one of the cell surface receptors that regulate the communication between cells and their microenvironment. Several integrins are overexpressed in many types of cancer cells and the tumor microvasculature and function in the mediation of various cellular events. Therefore, the surface modification of nanomaterials with integrin-specific ligands not only increases their binding affinity to cancer cells but also enhances the cellular uptake of nanomaterials through the intracellular trafficking of integrins. Moreover, the integrin-specific ligands themselves interfere with cancer migration and invasion by interacting with integrins, and this finding provides a novel direction for new treatment approaches in cancer nanomedicine. This article reviews the integrin-specific ligands that have been used in cancer nanomedicine and provides an overview of the recent progress in cancer diagnostics and therapeutic strategies involving the use of integrin-targeted nanomaterials.

Blood component ridable and CD44 receptor targetable nanoparticles based on a maleimide-functionalized chondroitin sulfate derivative

Chondroitin sulfate A-deoxycholic acid-polyethylene glycol-maleimide (CSA-DOCA-PEG-MAL; CDPM) nanostructures were designed for the transient binding of MAL with thiol in blood components and cell membranes, in addition to the CD44 receptor targeting, for the therapy of breast cancer. The spontaneous binding of free thiol groups in plasma proteins and blood cells with the MAL group of CDPM was significantly higher than that of CSA-DOCA-PEG (CDP). Enhanced cellular uptake and the in vitro antiproliferation efficacy of docetaxel (D)-loaded CDPM (CDPM/D) nanoparticles (NPs) in MCF-7 cells indicated dual-targeting effects based on MAL-thiol reactions and CSA-CD44 receptor interactions. Following intravenous injection in rats, reduced clearance and an elevated half-life of the drug was observed in the CDPM/D NPs compared to the CDP/D NPs. Taken together, MAL modification of CDP NPs could be a promising approach not only to enhance tumor targeting and penetration but also to extend the blood circulation time of anticancer drugs.

Dual-ligand functionalized carbon nanodots as green fluorescent nanosensors for cellular dual receptor-mediated targeted imaging

The conjugation of ligands to nanoparticles as drug delivery systems that target specific cells is a promising approach for the delivery of therapeutic agents to tumor cells. Herein, we prepared green-emission fluorescent carbon nanodots (CNDs) by a facile hydrothermal method with d-(+)-glucosamine hydrochloride and l-aspartic acid as the precursors, then covalently conjugated with folate (FA), polyethyleneimine (PEI) and hyaluronic acid (HA) to develop dual ligand-decorated nanocarriers (FA-PEI-HA-CNDs) for the targeted imaging of cancer cells. FA-PEI-HA-CNDs integrated the excellent fluorescence property of CNDs, and can be used for the real-time and noninvasive location tracking of cancer cells. The cellular uptake study demonstrated that FA-PEI-HA-CNDs markedly improved the internalization efficiency in A-549 cells via folate/CD44 receptor-mediated endocytosis in comparison with that of the A549 cells pretreated with excess FA, HA, and FA and HA. Therefore, these dual folate/CD44 receptor-targeted CNDs (FA-PEI-HA-CNDs) show promising potential for cancer detection, drug delivery, and individualized treatment as performance platforms.

Targeting integrins for cancer management using nanotherapeutic approaches: Recent advances and challenges

Integrins are the main cell surface receptors and execute multifaceted functions such as the bidirectional transmission of signals (i.e., inside-out and outside-in) and provide communication between cells and their microenvironments. Integrins are the key regulators of critical biological functions and contribute significantly to the promotion of cancer at almost every stage of disease progression from initial tumor formation to metastasis. Integrin expressions are frequently altered in different cancers, and consequently, several therapeutic strategies targeting integrins have been developed. Furthermore, nanotechnology-based approaches have been devised to overcome the intrinsic limitations of conventional therapies for cancer management, and have been shown to more precise, safer, and highly effective therapeutic tools. Although nanotechnology-based approaches have achieved substantial success for the management of cancer, certain obstacles remain such as inadequate knowledge of nano-bio interactions and the challenges associated with the three stages of clinical trials. This review highlights the different roles of integrins and of integrin-dependent signaling in various cancers and describes the applications of nanotherapeutics targeting integrins. In addition, we discuss RGD-based approaches and challenges posed to cancer management.

Nanoemulsion Structural Design in Co-Encapsulation of Hybrid Multifunctional Agents: Influence of the Smart PLGA Polymers on the Nanosystem-Enhanced Delivery and Electro-Photodynamic Treatment

In the present study, we examined properties of poly(lactide-co-glycolide) (PLGA)-based nanocarriers (NCs) with various functional or “smart” properties, i.e., coated with PLGA, polyethylene glycolated PLGA (PEG-PLGA), or folic acid-functionalized PLGA (FA-PLGA). NCs were obtained by double emulsion (water-in-oil-in-water) evaporation process, which is one of the most suitable approaches in nanoemulsion structural design. Nanoemulsion surface engineering allowed us to co-encapsulate a hydrophobic porphyrin photosensitizing dye—verteporfin (VP) in combination with low-dose cisplatin (CisPt)—a hydrophilic cytostatic drug. The composition was tested as a multifunctional and synergistic hybrid agent for bioimaging and anticancer treatment assisted by electroporation on human ovarian cancer SKOV-3 and control hamster ovarian fibroblastoid CHO-K1 cell lines. The diameter of PLGA NCs with different coatings was on average 200 nm, as shown by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. We analyzed the effect of the nanocarrier charge and the polymeric shield variation on the colloidal stability using microelectrophoretic and turbidimetric methods. The cellular internalization and anticancer activity following the electro-photodynamic treatment (EP-PDT) were assessed with confocal microscopy and flow cytometry. Our data show that functionalized PLGA NCs are biocompatible and enable efficient delivery of the hybrid cargo to cancer cells, followed by enhanced killing of cells when supported by EP-PDT.

Liposomal formulation of Galbanic acid improved therapeutic efficacy of pegylated liposomal Doxorubicin in mouse colon carcinoma

Galbanic acid (Gba), a sesquiterpene coumarin, with strong antiangiogenic activity could serve as an excellent anti-cancer agent. However, Gba is a poor water-solube which hampered its clinical application. In this study, a pegylated liposomal Gba (PLGba) with HSPC/Cholesterol/mPEG2000-DSPE (56.2, 38.3, 5.3% molar ratio) was developed by the thin film hydration plus extrusion and calcium acetate gradient remote loading method, to address the issue of poor Gba solubility. Moreover, an integrin-targeting ligand (RGD peptide, cyclo[Arg-Gly-Asp-D-Tyr-Cys]) was post-inserted into liposomes in order to increase Gba cell delivery. Using fluorescently-labeled model liposomes, it was found that the targeting could improve the integrin-mediated cellular uptake of the liposomes in vitro in human umbilical vein endothelial cells (HUVECs), and in vivo as evidenced by chicken chorioallantoic membrane angiogenesis (CAM) model. It also could enrich the liposome accumulation in C26 tumor. Interestingly, co-treatment with PLGba and pegylated liposomal doxorubicin (PLD, also known as Doxil®) had a synergistic and antagonistic antiproliferative effect on the C26 tumor cell line and the normal HUVEC, respectively. In C26 tumor bearing BALB/c mice, the PLGba and PLD combinatorial therapy improved the antitumor efficacy of the treatment as compared to those of single agents. This results have clear implications for cancer therapy.

Nanocomposites as biomolecules delivery agents in nanomedicine

Nanoparticles (NPs) are atomic clusters of crystalline or amorphous structure that possess unique physical and chemical properties associated with a size range of between 1 and 100 nm. Their nano-sized dimensions, which are in the same range as those of vital biomolecules, such as antibodies, membrane receptors, nucleic acids, and proteins, allow them to interact with different structures within living organisms. Because of these features, numerous nanoparticles are used in medicine as delivery agents for biomolecules. However, off-target drug delivery can cause serious side effects to normal tissues and organs. Considering this issue, it is essential to develop bioengineering strategies to significantly reduce systemic toxicity and improve therapeutic effect. In contrast to passive delivery, nanosystems enable to obtain enhanced therapeutic efficacy, decrease the possibility of drug resistance, and reduce side effects of "conventional" therapy in cancers. The present review provides an overview of the most recent (mostly last 3 years) achievements related to different biomolecules used to enable targeting capabilities of highly diverse nanoparticles. These include monoclonal antibodies, receptor-specific peptides or proteins, deoxyribonucleic acids, ribonucleic acids, [DNA/RNA] aptamers, and small molecules such as folates, and even vitamins or carbohydrates.

Photothermal therapy and photoacoustic imaging via nanotheranostics in fighting cancer

The nonradiative conversion of light energy into heat (photothermal therapy, PTT) or sound energy (photoacoustic imaging, PAI) has been intensively investigated for the treatment and diagnosis of cancer, respectively. By taking advantage of nanocarriers, both imaging and therapeutic functions together with enhanced tumour accumulation have been thoroughly studied to improve the pre-clinical efficiency of PAI and PTT. In this review, we first summarize the development of inorganic and organic nano photothermal transduction agents (PTAs) and strategies for improving the PTT outcomes, including applying appropriate laser dosage, guiding the treatment via imaging techniques, developing PTAs with absorption in the second NIR window, increasing photothermal conversion efficiency (PCE), and also increasing the accumulation of PTAs in tumours. Second, we introduce the advantages of combining PTT with other therapies in cancer treatment. Third, the emerging applications of PAI in cancer-related research are exemplified. Finally, the perspectives and challenges of PTT and PAI for combating cancer, especially regarding their clinical translation, are discussed. We believe that PTT and PAI having noteworthy features would become promising next-generation non-invasive cancer theranostic techniques and improve our ability to combat cancers.

Applying an innovative biodegradable self-assembly nanomicelles to deliver α-mangostin for improving anti-melanoma activity

α-Mangostin (αM), a traditional natural product with promising application of treating a series of diseases, was limited use in clinical due to its hydrophobicity. Herein, MPEG-PCL nanomicelles were used to embed the αM for resolving hydrophobicity and improving the anti-melanoma effect of the αM. The anti-melanoma activity and potential mechanisms of biodegradable αM/MPEG-PCL nanomicelles were investigated. The αM/MPEG-PCL nanomicelles possessed a stronger effect on anti-melanoma compared to the free αM both in vitro and in vivo with a low cytotoxicity in non-tumor cell lines. In the research of mechanisms, the αM/MPEG-PCL nanomicelles inhibited the proliferation of melanoma cell, induced apoptosis via both apoptosis pathways of intrinsic and exogenous in vitro, as well as suppressed tumor growth and restrained angiogenesis in vivo, which implied that the αM/MPEG-PCL nanomicelles have potential application as a novel chemotherapeutic agent in melanoma therapy.

Förster Resonance Energy Transfer-Activated Processes in Smart Nanotheranostics Fabricated in a Sustainable Manner

Multilayer nanocarriers loaded with optically activated payloads are gaining increasing attention due to their anticipated crucial role for providing new mechanisms of energy transfers in the health-oriented applications, as well as for energy storage and environmental protection. The combination of careful selection of optical components for efficient Förster resonance energy transfer, and surface engineering of the nanocarriers, allowed us to synthesize and characterize novel theranostic nanosystems for diagnosis and therapy of deep-seated tumors. The cargo, constrained within the oil core of the nanocapsules, composed of NaYF₄ :Tm⁺³ , Yb⁺³ up-converting nanoparticles together with a second-generation porphyrin-based photosensitizing agent-Verteporfin, assured requisite diagnostic and therapeutic functions under near-IR laser excitation. The outer polyaminoacid shell of the nanocapsules was functionalized with a ligand-poly(l-glutamic acid) functionalized by PEG-ylated folic acid-to ensure both a "stealth" effect and active targeting towards human breast cancer cells. The preparation criteria of all nanocarrier building blocks meet the requirements for sustainable and green chemistry practices. The multifunctionality of the proposed nanocarriers is a consequence of both the surface-functionalized organic exterior part, which was accessible for selective accumulation in cancer cells, and the hydrophobic optically active interior, which shows phototoxicity upon irradiation within the first biological window.

Advances in Receptor-Mediated, Tumor-Targeted Drug Delivery

Receptor-mediated drug delivery presents an opportunity to enhance therapeutic efficiency by accumulating drug within the tissue of interest and reducing undesired, off-target effects. In cancer, receptor overexpression is a platform for binding and inhibiting pathways that shape biodistribution, toxicity, cell binding and uptake, and therapeutic function. This review will identify tumor-targeted drug delivery vehicles and receptors that show promise for clinical translation based on quantitative in vitro and in vivo data. The authors describe the rationale to engineer a targeted drug delivery vehicle based on the ligand, chemical conjugation method, and type of drug delivery vehicle. Recent advances in multivalent targeting and ligand organization on tumor accumulation are discussed. Revolutionizing receptor-mediated drug delivery may be leveraged in the therapeutic delivery of chemotherapy, gene editing tools, and epigenetic drugs.

Mitochondria-targeting nanoparticles for enhanced microwave ablation of cancer

Although microwave ablation is widely used in the treatment of hepatocellular carcinoma, it is only recommended for the therapy of cancer with a diameter of 3 cm or less because of the limited heat transmission radius. Mitochondria play an important role in the apoptotic events of tumor cells. Here, we developed mitochondria-targeting zirconia (ZrO2) complex nanoparticles (MZCNs) as nanoagents for efficient cancer therapy by microwave ablation. The MZCNs are composed of ZrO2 nanoparticles encapsulating the microwave-sensitive ionic liquid (IL) and co-decorated with the mitochondria-targeting molecule of triphenylphosphonium (TPP), and the tumor cell-targeting peptide iRGD. The cell experiment results reveal that the amount of MZCNs accumulated in the tumor is obviously increased by the synergistically targeted delivery of TPP and iRGD peptide after administration by intravenous injection. Besides, the in vitro experiments demonstrate that MZCNs are distributed preferentially in the mitochondria with the assistance of TPP molecules. More importantly, the in vivo experiments in mice administered with MZCNs show that the effective area with a temperature above 42 °C was about 2.8-fold larger than that of the controls due to the targeting effect and better microwave sensitivity of the MZCNs. As such, the cancer in mice can be eradicated without recurrence, demonstrating the MZCNs as promising nanoagents for efficient cancer therapy by microwave ablation.

A dual-targeting reconstituted high density lipoprotein leveraging the synergy of sorafenib and antimiRNA21 for enhanced hepatocellular carcinoma therapy

Sorafenib (So) is a multi-target kinase inhibitor extensively used in clinic for hepatocellular carcinoma therapy. It demonstrated strong inhibition both in tumor proliferation and tumor angiogenesis, while hampered by associated cutaneous side-effect and drug resistance. The knockdown of miR-21 with antisense oligonucleotides (antimiRNA21) was regarded as an efficient strategy for increasing tumor sensibility to chemotherapy, which could be employed to appreciate the efficacy of So. Herein, we successfully formulated a dual-targeting delivery system for enhanced hepatocellular carcinoma therapy by encapsulating So and antimiRNA21 in RGD pentapeptide-modified reconstituted high-density lipoprotein (RGD-rHDL/So/antimiRNA21). The RGD and apolipoprotein A-I (ApoA-I) on nanoparticles (NPs) could drive the system simultaneously to tumor neovascular and parenchyma by binding to the overexpressed ανβ3-integrin and SR-B1 receptors, achieving precise delivery of therapeutics to maximize the efficacy. A series in vitro and in vivo experiments revealed that co-delivery of So and antimiRNA21 by RGD-rHDL significantly strengthened the anti-tumor and anti-angiogenic effect of So with negligible toxicity towards major organs, reversed drug-resistance and was capable of remodeling tumor environments. The constructed RGD-rHDL/So/antimiRNA21 with improved efficacy and excellent tumor targeting ability provided new idea for chemo-gene combined therapy in hepatocellular carcinoma.

STATEMENT OF SIGNIFICANCE

Sorafenib (So) is a multi-target kinase inhibitor which was approved by FDA as first-line drug for hepatocellular carcinoma (HCC) therapy. However, long term application of So in clinic was hampered by serious dermal toxicity and drug resistance. Although numerous researchers were devoted to finding alternatives or therapies as combination treatments with So to reach more desired therapeutic efficacy, the therapeutic options were still limited. The present study prepares RGD pentapeptide decorated biomimic reconstituted high-density lipoprotein (rHDL) loaded with So and antimiRNA21 (RGD-rHDL/So/antimiRNA21) for enhanced HCC therapy. The RGD-rHDL/So/antimiRNA21 NPs offer an effective platform for anti-tumor and anti-angiogenesis therapy in HCC and provide new approach to reverse drug-resistance of So for feasible clinical application.

Can dual-ligand targeting enhance cellular uptake of nanoparticles?

Dual ligand targeting to different types of over-expressed receptors on cell surfaces is a promising strategy in nanomedicine. Here, by using dissipative particle dynamics simulations, the effect of the surface distribution and physicochemical properties of dual ligands on the cellular uptake of nanoparticles is systematically studied. It is found that the spontaneous rearrangement of dual ligands (from random to patterned distribution) on the nanoparticle surface can enhance the cellular uptake of nanoparticles. While the short length of ligands may restrict the ligand rearrangement, nanoparticles coated with short dual ligands cannot be fully wrapped by cell membranes unless the dual ligands are initially separated on the nanoparticle surface. Besides, when there exists a length mismatch or non-specific interaction between the dual ligands, dual-ligand targeting cannot enhance the uptake efficiency, either. Further, we also provide the design guidelines for surface decoration, and find that the Janus nanoparticle can make the most of dual-ligand targeting. These results can help understand how to better use dual ligands to achieve efficient cellular uptake, which may provide significant insights into the optimal design of future nanomaterials in drug delivery.

A novel nanomissile targeting two biomarkers and accurately bombing CTCs with doxorubicin

Rare circulating tumor cells (CTCs) cause >50% of primary colorectal cancer survivors to develop deadly metastasis at 3-5 years after surgery; the current chemotherapies can do nothing about these cells. Herein, we synthesized a novel doxorubicin (DOX)-entrapped mesoporous silica nanoparticle (MSN), covalently-conjugated with two aptamers, for simultaneously targeting EpCAM and CD44, the typical surface biomarkers of colorectal CTCs. The nanomissile can specifically capture the metastasis-prone CTCs spiked in healthy human blood in a competitive-binding manner. The binding not only accurately delivers DOX into the cancer cells via the biomarker-mediated endocytosis to inhibit CTC viability through the DOX-dependent mechanism, but also inhibits the adhesion of cancer cells to the endothelium and the consequent transmembrane migration through the DOX-independent mechanism. The molecular entity of the conjugate and its pharmaceutical DOX encapsulation-releasing capacity are well-demonstrated via various physiochemical characterizations including gel electrophoresis, which proves the >8-hour biostability of the nanomissile in blood, long enough for it to chase CTCs in mice and synergistically inhibit the CTC-induced lung metastasis more potently than its single aptamer-conjugated counterparts and DOX itself. The present strategy may pave a new avenue for safe and effective cancer metastasis chemoprevention.

Strategies to Improve Cancer Photothermal Therapy Mediated by Nanomaterials

The deployment of hyperthermia-based treatments for cancer therapy has captured the attention of different researchers worldwide. In particular, the application of light-responsive nanomaterials to mediate hyperthermia has revealed promising results in several pre-clinical assays. Unlike conventional therapies, these nanostructures can display a preferential tumor accumulation and thus mediate, upon irradiation with near-infrared light, a selective hyperthermic effect with temporal resolution. Different types of nanomaterials such as those based on gold, carbon, copper, molybdenum, tungsten, iron, palladium and conjugated polymers have been used for this photothermal modality. This progress report summarizes the different strategies that have been applied so far for increasing the efficacy of the photothermal therapeutic effect mediated by nanomaterials, namely those that improve the accumulation of nanomaterials in tumors (e.g. by changing the corona composition or through the functionalization with targeting ligands), increase nanomaterials' intrinsic capacity to generate photoinduced heat (e.g. by synthesizing new nanomaterials or assembling nanostructures) or by optimizing the parameters related to the laser light used in the irradiation process (e.g. by modulating the radiation wavelength). Overall, the development of new strategies or the optimization and combination of the existing ones will surely give a major contribution for the application of nanomaterials in cancer PTT.

Novel, nano-sized, liposome-encapsulated polyamidoamine dendrimer derivatives facilitate tumour targeting by overcoming the polyethylene glycol dilemma and integrin saturation obstacle

Drug delivery systems (DDSs) commonly employ arginine-glycine-aspartic acid (RGD) peptides with polyethylene glycol (PEG)-dependent enhanced permeability and retention (EPR) effect to optimise tumour-targeting. However, the PEG dilemma and integrin saturation obstacle are major challenges. To address these issues, we constructed a novel, nano-sized DDS by encapsulating doxorubicin (DOX)-loaded folic acid derivatives of polyamidoamine dendrimer (PAMAM G5.0) in cyclic RGD-tyrosine-lysine pentapeptide (c[RGDyK])-modified liposomes (RGD-SL[FND/DOX]), prepared using thin-film hydration, film-dispersion and hydration-sonication. The liposomes were PEGylated, sterically stabilised and pH-sensitive. In vitro, RGD-SL[FND/DOX] showed pH-sensitive holistic FND/DOX release, and pH-dependent uptake and cytotoxicity in human cancer KB cells. At pH 7.4, RGD-SL[FND/DOX] demonstrated greater cellular uptake and cytotoxicity than relevant control formulations (except FND/DOX) did, although this advantage disappeared at pH 6.5. In vivo, RGD-SL[FND/DOX] inhibited S180 sarcoma xenografted tumour growth in Kunming mice more effectively than FND/DOX did. These findings demonstrate the feasibility of constructing double-stage tumour-targeting nano-sized DDSs such as RGD-SL[FND/DOX]. c[RGDyK] and the EPR effect, facilitated by the particle size (about 110 nm) and PEGylation, helped to target the DDS to the tumour tissue, while the subsequent pH-dependent release of FND/DOX and folic acid-mediated endocytosis specifically targeted the tumour cells, thereby overcoming the PEG dilemma and integrin saturation obstacle.

Nanoparticle Functionalization and Its Potentials for Molecular Imaging

Functionalization enhances the properties and characteristics of nanoparticles through surface modification, and enables them to play a major role in the field of medicine. In molecular imaging, quality functional images are required with proper differentiation which can be seen with high contrast to obtain viable information. This review article discusses how functionalization enhances molecular imaging and enables multimodal imaging by which images with combination of functions particular to each modality can be obtained. This also explains how nanoparticles interacting at molecular level, when functionalized with molecules can target the cells of interest or substances with high specificity, reducing background signal and allowing simultaneous therapies to be carried out while imaging. Functionalization allows imaging for a prolonged period and enables to track the cells over a period of time. Recent researches and progress in functionalizing the nanoparticles to specifically enhance bioimaging with different modalities and their applications are reviewed in this article.