IR-780 Loaded Phospholipid Mimicking Homopolymeric Micelles for Near-IR Imaging and Photothermal Therapy of Pancreatic Cancer

Nanoplatforms for Magnetic-Photo-Heating of Thermo-Resistant Tumor Cells: Singular Synergic Therapeutic Effects at Mild Temperature

A self-assemble amphiphilic diblock copolymer that can incorporate iron oxide nanocubes (IONCs) in chain-like assemblies as heat mediators for magnetic hyperthermia (MHT) and tuneable amounts of IR780 dye as agent for photothermal therapy (PTT) is developed. MHT-heating performance of photobeads in viscous media have the same heat performances in water at magnetic field conditions of clinical use. Thanks to IR780, the photobeads are activated by infrared laser light within the first biological window (808 nm) with a significant enhancement of photo-stability of IR780 enabling the raise of the temperature at therapeutic values during multiple PTT cycles and showing unchanged optical features up to 8 days. Moreover, the photobeads fluorescent signal is preserved once internalized by glioblastoma multiforme (GBM) cells. Peculiarly, the photobeads are used as toxic agents to eradicate thermo-resistant GBM cells at mild heat, as low as 41 °C, with MHT and PTT both of clinical use. Indeed, a high U87 GBM cell mortality percentage is obtained only with dual MHT/PTT while each single treatment dose not provide the same cytotoxic effects. Only for the combined treatment, the cell death mechanism is assigned to clear sign of apoptosis as observed by structural/morphological cell studies and enhanced lysosome permeability.

HI-6-Loaded Vehicle of Liposomes Mediated by an Amphiphilic Pillar[5]arene against Paraoxon Poisoning

Organophosphate (OP) intoxication has become a severe common health matter all over the world. For the treatment of acute OP poisoning, the effective intracerebral delivery of acetylcholinesterase reactivators is crucial. Here, an amphiphilic hydrazide-pillar[5]arene (HP5A-6C), which could be readily integrated into liposomal bilayers' zwitterionic disaturated phosphatidylcholine (DSPC), was synthesized. A T7 peptide-containing guest (G) was attached on the surface via a noncovalent interaction to make mixed liposomes a particularly appealing candidate for brain-targeting delivery. Such coassembly could remain stable at room temperature for up to 6 weeks, and safety evaluations initially verified its fine biological compatibility. The hydrophilic interiors of T7/HP5A-6C@DSPC could further load HI-6 with 89.70% encapsulation efficiency. Support for brain-targeting potency came from imaging results. Notably, intravenous injection of HI-6-loaded vesicles exhibited a remarkable therapeutic effect on paraoxon (POX)-poisoned mice, effectively alleviating seizures and brain damage and significantly increasing the improving survival rate to 60% over the course of 7 days.

Size- and Shape-controlled Biodegradable Polymer Brushes Based on l-Amino Acid for Intracellular Drug Delivery and Deep-Tissue Penetration

We report size- and shape-controlled polymer brushes based on l-amino acid bioresource and study the role of polymer topology on the enzymatic biodegradation and deep-tissue penetration under in vitro and in vivo. For this purpose, l-tyrosine-based propargyl-functionalized monomer is tailor-made and polymerized via solvent-free melt polycondensation strategy to yield hydrophobic and clickable biodegradable poly(ester-urethane)s. Postpolymerization click chemistry strategy is applied to make well-defined amphiphilic one-dimensional rodlike and three-dimensional spherical polymer brushes by merely varying the lengths of PEG-azides in the reaction. These core-shell polymer brushes are found to be nontoxic and nonhemolytic and capable of loading clinical anticancer drug doxorubicin and deep-tissue penetrable near-infrared biomarker IR-780. In vitro enzymatic drug-release kinetics and lysotracker-assisted real-time live-cell confocal bioimaging revealed that the rodlike polymer brush is superior than its spherical counterparts for faster cellular uptake and enzymatic biodegradation at the endolysosomal compartments to release DOX at the nucleus. Further, in vivo live-animal bioimaging by IVIS technique established that the IR-780-loaded rodlike polymer brush exhibited efficient deep-tissue penetration ability and emphasized the importance of polymer brush topology control for biological activity. Polymer brushes exhibit good stability in the blood plasma for more than 72 h, they predominately accumulate in the digestive organs like liver and kidney, and they are less toxic to heart and brain tissues. IVIS imaging of cryotome tissue slices of organs confirmed the deep-penetrating ability of the polymer brushes. The present investigation opens opportunity for bioderived and biodegradable polymer brushes as next-generation smart drug-delivery scaffolds.

Exploiting the Photo-Physical Properties of Metal Halide Perovskite Nanocrystals for Bioimaging

Perovskite nanomaterials have recently been exploited for bioimaging applications due to their unique photo-physical properties, including high absorbance, good photostability, narrow emissions, and nonlinear optical properties. These attributes outperform conventional fluorescent materials such as organic dyes and metal chalcogenide quantum dots and endow them with the potential to reshape a wide array of bioimaging modalities. Yet, their full potential necessitates a deep grasp of their structure-attribute relationship and strategies for enhancing water stability through surface engineering for meeting the stringent and unique requirements of each individual imaging modality. This review delves into this evolving frontier, highlighting how their distinctive photo-physical properties can be leveraged and optimized for various bioimaging modalities, including visible light imaging, near-infrared imaging, and super-resolution imaging.

The bioengineered and multifunctional nanoparticles in pancreatic cancer therapy: Bioresponisive nanostructures, phototherapy and targeted drug delivery

The multidisciplinary approaches in treatment of cancer appear to be essential in term of bringing benefits of several disciplines and their coordination in tumor elimination. Because of the biological and malignant features of cancer cells, they have ability of developing resistance to conventional therapies such as chemo- and radio-therapy. Pancreatic cancer (PC) is a malignant disease of gastrointestinal tract in which chemotherapy and radiotherapy are main tools in its treatment, and recently, nanocarriers have been emerged as promising structures in its therapy. The bioresponsive nanocarriers are able to respond to pH and redox, among others, in targeted delivery of cargo for specific treatment of PC. The loading drugs on the nanoparticles that can be synthetic or natural compounds, can help in more reduction in progression of PC through enhancing their intracellular accumulation in cancer cells. The encapsulation of genes in the nanoparticles can protect against degradation and promotes intracellular accumulation in tumor suppression. A new kind of therapy for cancer is phototherapy in which nanoparticles can stimulate both photothermal therapy and photodynamic therapy through hyperthermia and ROS overgeneration to trigger cell death in PC. Therefore, synergistic therapy of phototherapy with chemotherapy is performed in accelerating tumor suppression. One of the important functions of nanotechnology is selective targeting of PC cells in reducing side effects on normal cells. The nanostructures are capable of being surface functionalized with aptamers, proteins and antibodies to specifically target PC cells in suppressing their progression. Therefore, a specific therapy for PC is provided and future implications for diagnosis of PC is suggested.

Simple preparation of POxylated nanomaterials for cancer chemo-PDT/PTT

Near infrared (NIR) light-responsive nanomaterials hold potential to mediate combinatorial therapies targeting several cancer hallmarks. When irradiated, these nanomaterials produce reactive oxygen species (photodynamic therapy) and/or a temperature increase (photothermal therapy). These events can damage cancer cells and trigger the release of drugs from the nanomaterials' core. However, engineering nanomaterials for cancer chemo-photodynamic/photothermal therapy is a complex process. First, nanomaterials with photothermal capacity are synthesized, being then loaded with photosensitizers plus chemotherapeutics, and, finally functionalized with polymers for achieving suitable biological properties. To overcome this limitation, in this work, a novel straightforward approach to attain NIR light-responsive nanosystems for cancer chemo-photodynamic/photothermal therapy was established. Such was accomplished by synthesizing poly(2-ethyl-2-oxazoline)-IR780 amphiphilic conjugates, which can be assembled into nanoparticles with photodynamic/photothermal capabilities that simultaneously encapsulate Doxorubicin (DOX/PEtOx-IR NPs). The DOX/PEtOx-IR NPs presented a suitable size and surface charge for cancer-related applications. When irradiated with NIR light, the DOX/PEtOx-IR NPs produced singlet oxygen as well as a smaller thermic effect that boosted the release of DOX by 1.7-times. In the in vitro studies, the combination of DOX/PEtOx-IR NPs and NIR light could completely ablate breast cancer cells (viability ≈ 4 %), demonstrating the enhanced outcome arising from the nanomaterials' chemo-photodynamic/photothermal therapy.

Supramolecular Polypeptide Self-Assembly Mediated In Situ Elicitation of Robust Innate and Adaptive Immune Responses Boosts Immunogenic Photothermal Therapy toward "Cold" Tumor

As a promising cancer treatment modality that has emerged, photothermal therapy can harness antitumor immunity by triggering immunogenic cell death (ICD) in addition to direct cell ablation. However, the immuno-stimulation induced by PTT alone is insufficient to achieve satisfactory cancer eradication, especially in immunologically "cold" tumors due to their harsh immunosuppressive microenvironment. Effective activation of the innate immune system is indispensable to boost a robust adaptive antitumor immune response typically initiated by dendritic cells (DCs). Herein the above issues are addressed by constructing an environmentally responsive supramolecular nanoself-assembly (PSAs) derived from a novel polypeptide-based block copolymer, which is capable of co-load photothermal immunomodulators efficiently under structure-guided π-π stacking interactions. In the murine model of 4T1 xenograft tumors, the fabricated PSAs with payloads trigger both adaptive and innate immune responses in situ through activation of ICD as well as STING-dependent signal pathway. The findings reveal a new mechanism of harnessing photothermal therapy toward immunologically "cold" tumors.

Poly(2-ethyl-2-oxazoline)-IR780 conjugate nanoparticles for breast cancer phototherapy

Aims: To address the limitations of IR780 by preparing hydrophilic polymer-IR780 conjugates and to employ these conjugates in the assembly of nanoparticles (NPs) intended for cancer photothermal therapy. Materials & methods: The cyclohexenyl ring of IR780 was conjugated for the first time with thiol-terminated poly(2-ethyl-2-oxazoline) (PEtOx). This novel poly(2-ethyl-2-oxazoline)-IR780 (PEtOx-IR) conjugate was combined with D-α-tocopheryl succinate (TOS), leading to the assembly of mixed NPs (PEtOx-IR/TOS NPs). Results: PEtOx-IR/TOS NPs displayed optimal colloidal stability as well as cytocompatibility in healthy cells at doses within the therapeutic range. In turn, the combination of PEtOx-IR/TOS NPs and near-infrared light reduced heterotypic breast cancer spheroid viability to just 15%. Conclusion: PEtOx-IR/TOS NPs are promising agents for breast cancer photothermal therapy.

Construction of Folate-Conjugated and pH-Responsive Cell Membrane Mimetic Mixed Micelles for Desirable DOX Release and Enhanced Tumor-Cellular Target

Smart multifunctional polymeric micelles are in urgent demand for future cancer diagnosis and therapy. In this paper, doxorubicin (DOX)-loaded folic acid (FA)-targeting and pH-responsive cell membrane mimetic mixed micelles of P(DMAEMA-co-MaPCL) (PCD) and FA-P(MPC-co-MaPCL) (PMCF) (mass ratio 5/5) were prepared by a dialysis method. The micelle size, morphology, X-ray powder diffraction (XRD), pH responsiveness, in vitro DOX release, cytotoxicity, and cellular uptake were studied in detail. The results indicated that DOX could be efficiently loaded into mixed micelles (PDMCF micelles), and the DOX-loaded mixed micelles (DOX@PDMCF micelles) exhibited a size of 150 nm and pH-responsive DOX release in an extended period. Furthermore, the DOX@PDMCF micelles could efficiently suppress the proliferation of tumor cells, HeLa and MCF-7 cells. Our data suggest that the DOX@PDMCF micelles have the potential to be applied in tumor therapy, especially for treating various folate receptor overexpressed tumors.

Tailoring the multi-functional properties of phospholipids for simple to complex self-assemblies

The unique interfacial properties, huge diversity, and biocompatible nature of phospholipids make them an attractive pharmaceutical excipient. The amphiphilic nature of these molecules offers them the property to self-assemble into distinct structures. The solubility, chemical and structural properties, surface charge, and critical packing parameters of phospholipids play an essential role during formulation design. This review focuses on the relationship between the structural features of a phospholipid molecule and the formation of different lipid-based nanocarrier drug delivery systems. This provides a rationale and guideline for the selection of appropriate phospholipids while designing a drug delivery system. Finally, we refer to relevant recent case studies covering different types of phospholipid-based systems including simple to complex assemblies. Different carriers in the size range of 50 nm to a few microns can be prepared using phospholipids. The carriers can be delivered through oral, intravenous, nasal, dermal, transmucosal, and subcutaneous routes. A wide range of applicability can be achieved by incorporating various hydrophilic and lipophilic additives in the phospholipid bilayer. Advanced research has led to the discovery of phospholipid complexes and cell membrane mimicking lipids. Overall, phospholipids remain a versatile pharmaceutical excipient for drug delivery. They play multiple roles as solubilizer, emulsifier, surfactant, permeation enhancer, coating agent, release modifier, and liposome former.

NIR-activated nanosystems with self-modulated bacteria targeting for enhanced biofilm eradication and caries prevention

The efficacious delivery of antimicrobial drugs to intractable oral biofilms remains a challenge due to inadequate biofilm penetration and lack of pathogen targeting. Herein, we have developed a microenvironment-activated poly(ethylene glycol) (PEG)-sheddable nanoplatform to mediate targeted delivery of drugs into oral biofilms for the efficient prevention of dental caries. The PEGylated nanoplatform with enhanced biofilm penetration is capable of deshielding the PEG layer under slightly acidic conditions in a PEG chain length-dependent manner to re-expose the bacteria-targeting ligands, thereby facilitating targeted codelivery of ciprofloxacin (CIP) and IR780 to the bacteria after accumulation within biofilms. The nanoplatform tends to induce bacterial agglomeration and suffers from degradation in the acidic oral biofilm microenvironment, triggering rapid drug release on demand around bacterial cells. The self-modulating nanoplatform under near-infrared (NIR) irradiation accordingly displays greatly augmented potency in oral biofilm penetration and disruption compared with drugs alone. Topical oral treatment with nanoplatforms involving synergetic pharmacological and photothermal/photodynamic trinary therapy results in robust biofilm dispersion and efficacious suppression of severe tooth decay in rats. This versatile nanoplatform can promote local accumulation and specific drug transport into biofilms and represents a new paradigm for targeted drug delivery for the management of oral biofilm-associated infections.

A plasmon-enhanced fluorescent gold coated novel lipo-polymeric hybrid nanosystem: synthesis, characterization and application for imaging and photothermal therapy of breast cancer

This study reports a hybrid lipo-polymeric nanosystem (PDPC NPs) synthesized by a modified hydrogel-isolation technique. The ability of the nanosystem to encapsulate hydrophilic and hydrophobic molecules has been demonstrated, and their enhanced cellular uptake has been observed in vitro. The PDPC NPs, surface coated with gold by in situ reduction of chloroauric acid (PDPC-Au NPs), showed a photothermal transduction efficacy of ∼65%. The PDPC-Au NPs demonstrated an increase in intracellular ROS, triggered DNA damage and resulted in apoptotic cell death when tested against breast cancer cells (MCF-7). The disintegration of PDPC-Au NPs into smaller nanoparticles with near-infrared (NIR) laser irradiation was understood using transmission electron microscopy imaging. The lipo-polymeric hybrid nanosystem exhibited plasmon-enhanced fluorescence when loaded with IR780 (a NIR dye), followed by surface coating with gold (PDPC-IR-Au NPs). This paper is one of the first reports on the plasmon-enhanced fluorescence within a nanosystem by simple surface coating of Au, to the best of our knowledge. This plasmon-enhanced fluorescence was unique to the lipo-polymeric hybrid system, as the same was not observed with a liposomal nanosystem. The plasmon-enhanced fluorescence of PDPC-IR-Au NPs, when applied for imaging cancer cells and zebrafish embryos, showed a strong fluorescence signal at minimal concentrations of the dye. The PDPC-IR-Au NPs were also applied for photothermal therapy of breast cancer in vitro and in vivo, and the results depicted significant therapeutic benefits.

Hyaluronic acid-modified, IR780-conjugated and doxorubicin-loaded reduced graphene oxide for targeted cancer chemo/photothermal/photodynamic therapy

We used reduced graphene oxide (rGO), which has two times higher photothermal conversion efficiency than graphene oxide (GO), as a photothermal agent for cancer photothermal therapy (PTT). By conjugating a photosensitizer IR780 to rGO, the IR780-rGO could be endowed with reactive oxygen species (ROSs) generation ability for concurrent photodynamic therapy (PDT). The IR780-rGO was coated with hyaluronic acid (HA) by electrostatic interaction to facilitate its intracellular uptake by U87 glioblastoma cells. The IR780-rGO/HA was loaded with doxorubicin (DOX) for chemotherapy (CT), to develop a pH-responsive drug delivery nano-platform for targeted multimodal cancer CT/PTT/PDT. We fully characterized the properties of all nanocomposites during the synthesis steps. The high loading efficiency of DOX on IR780-rGO-HA provides 3 mg/mg drug loading, while IR780-rGO-HA/DOX shows 3 times higher drug release at endosomal pH value (pH 5) than at pH 7.4. The mechanism for PTT/PDT was confirmed from the ability of IR780-rGO-HA to induce time-dependent temperature rise, synthesis of heat shock protein 70 (HSP70) and generation of intracellular ROSs, after exposure to 808 nm near infrared (NIR) laser light. The nano-vehicle IR780-rGO-HA shows high biocompatibility toward 3T3 fibroblast and U87 cancer cell lines, as well as enhanced intracellular uptake by U87 through active targeting. This translates into increased cytotoxicity of IR780-rGO-HA/DOX, by lowering the drug half-maximal inhibitory concentration (IC₅₀) from 0.7 to 0.46 μg/mL. This IC₅₀ is further decreased to 0.1 μg/mL by irradiation with NIR laser for 3 min at 1.5 W/cm². The elevated cancer cell killing mechanism was supported from flow cytometry analysis, where the highest cell apoptosis/necrosis rate was observed in combination CT/PTT/PDT. Using xenograft tumor model created by subcutaneous implantation of U87 cells in nude mice, IR780-rGO-HA/DOX delivered through intravenous (IV) injection and followed with 808 nm laser treatment for 5 min at 1.5 W/cm² results in the lowest tumor growth rate, with negligible change of tumor volume from its original value at the end 20-day observation period. The therapeutic efficacy was supported from inhibited cell proliferation rate, increased cell apoptosis rate, and increased production of HSP70 from immunohistochemical staining of tumor tissue slices. The safety of the NIR-assisted multimodal cancer treatment could be confirmed from non-significant change of body weight and hematological parameters of blood sample. Taken together, we conclude that IV delivery of IR780-rGO-HA/DOX plus NIR laser treatment is an effective nanomedicine approach for combination cancer therapy.

VB12-Sericin-PBLG-IR780 Nanomicelles for Programming Cell Pyroptosis via Photothermal (PTT)/Photodynamic (PDT) Effect-Induced Mitochondrial DNA (mitoDNA) Oxidative Damage

Pyroptosis, a kind of programmed cell death involving inflammation, might be a powerful way to fight against tumors, for example, using immunotherapy. However, how to trigger pyroptosis in cancer cells is an important issue. Photothermal (PTT)/photodynamic (PDT) therapy is a crucial strategy for inducing cancer cell pyroptosis with noninvasiveness. In this work, a sericin derivative modified with poly(γ-benzyl-l-glutamate) (PBLG) could self-assemble and was stable in an aqueous environment. Furthermore, the sericin derivative was conjugated with the tumor-targeting agent VB12 and loaded with IR780. Finally, we successfully synthesized VB12-sericin-PBLG-IR780 nanomicelles. The as-designed nanomicelles showed appropriate particle sizes, spherical morphology, improved photothermal stability, and high photothermal conversion efficiency (∼40%), which generated reactive oxygen species (ROS) simultaneously. Through enhanced cellular uptake, VB12-sericin-PBLG-IR780 could deliver more IR780 into cancer cells. With near-infrared (NIR), the VB12-sericin-PBLG-IR780 could significantly inhibit the expression of ATP synthase, called ATP5MC3, followed by mitochondrial damage. The presence of mitochondrial reactive oxygen species (mitoROS) led to oxidative damage of mitochondrial DNA (mitoDNA), which further activates NLRP3/Caspase-1/gasdermin D (GSDMD)-dependent pyroptosis and could promote dendritic cell (DC) maturation by pyroptosis. Furthermore, our data showed that VB12-sericin-PBLG-IR780 could achieve a brilliant antitumor effect and could activate DC maturation, initiate T-cell recruiting, and prime adaptive antitumor efficiency. Overall, our well-prepared nanomicelles might offer a tumor-targeted approach for programmed cell pyroptosis and inducing antitumor immunity via photothermal PTT/PDT effect-induced mitoDNA oxidative damage.

Indocyanine-type Infrared-820 Encapsulated Polymeric Nanoparticle-Assisted Photothermal Therapy of Cancer

Organic small-molecule photosensitizers are well-characterized and known for the light-responsive treatment modality including photodynamic therapy. Compared with ultraviolet-visible (UV-vis) light used in conventional photodynamic therapy with organic photosensitizers, near-infrared (NIR) light from 700 to 900 nm is less absorbed and scattered by biological tissue such as hemoglobin, lipids, and water, and thus, the use of NIR excitation can greatly increase the penetration depth and emission. Additionally, NIR light has lower energy than UV-vis that can be beneficial due to less activation of fluorophores present in tissues upon NIR irradiation. However, the low water stability, nonspecific distribution, and short circulation half-life of the organic photosensitizers limit its broad biological application. NIR responsive small-molecule fluorescent agents are the focus of extensive research for combined molecular imaging and hyperthermia. Recently a new class of NIR dye, IR-820 with excitation and emission wavelengths of 710 and 820 nm, has been developed and explored as an alternative platform to overcome some of the limitations of the most commonly used gold nanoparticles for photothermal therapy of cancer. Herein, we synthesized a core-shell biocompatible nanocarrier envelope made up of a phospholipid conjugated with poly(ethylene glycol) as a shell, while poly(lactic glycolic acid) (PLGA) was used as a core to encapsulate IR-820 dye. The IR-820-loaded nanoparticles were prepared by nanoprecipitation and characterized for their physicochemical properties and photothermal efficiency. These nanoparticles were monodispersed and highly stable in physiological pH with the hydrodynamic size of 103 ± 8 nm and polydispersity index of 0.163 ± 0.031. The IR-820-loaded nanocarrier showed excellent biocompatibility in the dark, whereas remarkable phototoxicity was observed with breast cancer cells (MCF-7) upon NIR laser excitation. Therefore, the IR-820-loaded phospholipid mimicking biodegradable lipid-polymer composite nanoparticles could have great potential for cancer theranostics.

Near-Infrared Responsive Membrane Nanovesicles Amplify Homologous Targeting Delivery of Anti-PD Immunotherapy against Metastatic Tumors

The major obstacles of anti-PD therapy in metastatic tumors are limited drug delivery in primary tumors and metastatic foci, and the lack of tumor-infiltrating lymphocytes (TILs). Here, the authors constructed a novel cellular membrane nanovesicles platform (M/IR NPs) based on homologous targeting and near-infrared (NIR) responsive release strategy to potentiate PD-1/PD-L1 blockade therapy against metastatic tumors. In tumor-bearing mice, biomimetic M/IR NPs targeted both primary tumors and their lung metastases. Upon laser irradiation, M/IR NPs reduced cancer-associated fibroblasts (CAFs) in tumor microenvironment, thus increasing the penetration of TILs. When shed from homologous tumor cell membranes, positively charged nanoparticles (IR NPs) core can capture released tumor-associated antigens, thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. When the photothermal conversion temperature under NIR-laser is higher than 42 °C, M/IR NPs initiated the rupture of cell membranes and the responsive release of PD-1/PD-L1 inhibitor BMS, which significantly attenuated tumor-associated immunosuppression and synergistically induced T cellular immunity to inhibit the tumor growth and metastasis. Overall, biomimetic M/IR NPs can improve the targeting and therapeutic efficacy of anti-PD therapy in primary tumors and metastases, opening up a new avenue for the diagnosis and treatment of metastatic tumors in the future.

Photodynamic therapy with the dual-mode association of IR780 to PEG-PLA nanocapsules and the effects on human breast cancer cells

IR780 is a near-infrared fluorescent dye, which can be applied as a photosensitizer in photodynamic (PDT) and photothermal (PTT) therapies and as a biodistribution tracer in imaging techniques. We investigated the growth and migration inhibition and mechanism of death of breast tumor cells, MCF-7 and MDA-MB-231, exposed to polymeric nanocapsules (NC) comprising IR780 covalently linked to the biodegradable polymer PLA (IR-PLA) and IR780 physically encapsulated (IR780-NC) in vitro. Both types of NC had mean diameters around 120 nm and zeta potentials around -40 mV. IR-PLA-NC was less cytotoxic than IR780 NC to a non-tumorigenic mammary epithelial cell line, MCF-10A, which is an important aspect of selectivity. Free-IR780 was more cytotoxic than IR-PLA-NC for MCF-7 and MDA-MB-231 cells after illumination with a 808 nm laser. IR-PLA NC was effective to inhibit colony formation (50%) and migration (30-40%) for both cancer cell lines. MDA-MB-231 cells were less sensitive to all IR780 formulations compared to MCF-7 cells. Cell uptake was higher with IR-PLA-NC than with IR780-NC and free-IR780 in both cancer cell lines (p < 0.05). NC uptake was higher in MCF-7 than in MDA-MB-231 cells. IR-PLA-NC induced a higher percentage of apoptosis upon illumination in MDA-MB-231 than in MCF-7 cells. The necrosis mechanism of death predominated in treatments with free-IR780 and with encapsulated IR780 NC, suggestive of damages at the plasma membrane. IR780 conjugated with PLA increased the apoptotic pathway and demonstrated potential as a multifunctional theranostic agent for breast cancer treatment with increased cellular uptake, photodynamic activity and more reliable tracking in cell-image studies.

Thermal-sensitive lipid nanoparticles potentiate anti-PD therapy through enhancing drug penetration and T lymphocytes infiltration in metastatic tumor

The response rate of anti-PD therapy in most cancer patients remains low. Therapeutic drug and tumor-infiltrating lymphocytes (TILs) are usually obstructed by the stromal region within tumor microenvironment (TME) rather than distributed around tumor cells, thus unable to induce the immune response of cytotoxic T cells. Here, we constructed the cationic thermosensitive lipid nanoparticles IR780/DPPC/BMS by introducing cationic NIR photosensitizer IR-780 iodide (IR780) modified lipid components, thermosensitive lipid DPPC and PD-1/PD-L1 inhibitor BMS202 (BMS). Upon laser irradiation, IR780/DPPC/BMS penetrated into deep tumor, and reduced cancer-associated fibroblasts (CAFs) around tumor cells to remodel the spatial distribution of TILs in TME. Interestingly, the cationic IR780/DPPC/BMS could capture released tumor-associated antigens (TAAs), thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. Moreover, IR780/DPPC/BMS initiated gel-liquid crystal phase transition under laser irradiation, accelerating the disintegration of lipid bilayer structure and leading to the responsive release of BMS, which would reverse the tumor immunosuppression state by blocking PD-1/PD-L1 pathway for a long term. This combination treatment can synergistically exert the antitumor immune response and inhibit the tumor growth and metastasis.

Biomimetic recombinant of red blood cell membranes for improved photothermal therapy

Background

RBC membrane derived nanoparticles (NPs) represent an emerging platform with prolonged circulation capacity for the delivery of active substances. For functionalize derived RBCs NPs, various strategies, such as biomimetic rebuilding of RBCs, chemical modification or inserting ligands, have been carried out to improve their performance. However, one potential adverse effect for these methods is the structural failure of membrane proteins, consequently affecting its original immune escape function.

Results

In this study, we reported a green technology of “disassembly-reassembly” to prepare biomimetic reconstituted RBCs membrane (rRBCs) by separating the endogenous proteins and lipids from nature RBC membrane. IR780 iodide was used as a pattern drug to verify the property and feasibility of rRBCs by constructing IR780@rRBC NPs with IR780@RBC NPs and free IR780 as controls. The results demonstrated the superiority of IR780@rRBC NPs in toxicity, stability, pharmacokinetics and pharmacodynamics compared with IR780@rRBC and free IR780.

Conclusions

The reported “disassembly-reassembly” strategy shows great potential to produce controllable and versatile rRBC membrane-inspired delivery platform, which may be used to overcome the deficiency of functionalization in cell membrane coated nanoparticles .

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00949-7.

Ultrasound-Mediated Cavitation Enhances EGFR-Targeting PLGA-PEG Nano-Micelle Delivery for Triple-Negative Breast Cancer Treatment

Simple Summary

Triple-negative breast cancer (TNBC) with negative expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER2) is considered to be associated with poorer outcomes and a higher risk of recurrence or metastasis owing to a lack of effective targeted therapeutic drugs. The epidermal growth factor receptor (EGFR) functions is a driver of disease progression in most of TNBC that represents a viable target that can be leveraged to guide the intra-tumoral delivery of chemotherapeutic drugs in TNBC patients. Moreover, ultrasound-mediated cavitation (UMC) strategies increase tissue permeability and extravasation through nuclei-dependent cavitation via sonoporation, thus enabling drugs to better enter target tissues. In this research, a combination of active, targeting nano-micelles and UMC was able to inhibit TNBC tumor growth effectively at lower concentrations while reducing treatment-related toxicity. Thus, this is a very promising treatment strategy in the clinical therapy with TNBC and other cancer types.

Abstract

Triple-negative breast cancer (TNBC) is highly recurring and metastatic breast cancer with overexpressing epidermal growth factor receptor (EGFR). Herein, a series of in vitro and in vivo analyses were used to explore the therapeutic effect of EGFR-targeting nano-micelles (PLGA-PEG/DOX@anti-EGFR) combined with ultrasound-mediated cavitation (UMC). The prepared nano-micelle drug carriers have good biocompatibility and can greatly increase the drug accumulation in tumor regions, thereby reducing off-target toxicity while enhancing anti-tumor efficacy. Moreover, an in vivo analysis of the practical utility of this treatment modality was conducted by using SonoVue^TM microbubbles to achieve cavitation under different power intensity levels, with an ultrasonic power intensity of 0.5 W/cm² maximizing the intra-tumoral blood perfusion. Relative to PLGA-PEG@DOX/anti-EGFR nano-micelles treatment alone, the combination with UMC was better able to suppress tumor growth even at low concentrations. As such, combining actively targeted drug-carrier molecules with UMC represents an effective approach to enhancing therapeutic efficacy while reducing the adverse, systemic effects associated with DOX and other chemotherapeutic drugs, and it can be considered as a promising clinical prospect in the treatment of TNBC.

Folate-targeted Pluronic-chitosan nanocapsules loaded with IR780 for near-infrared fluorescence imaging and photothermal-photodynamic therapy of ovarian cancer

Herein, we report the fabrication of a nanotherapeutic platform integrating near-infrared (NIR) imaging with combined therapeutic potential through photodynamic (PDT) and photothermal therapies (PTT) and recognition functionality against ovarian cancer. Owing to its NIR fluorescence, singlet oxygen generation and heating capacity, IR780 iodide is exploited to construct a multifunctional nanosystem for single-wavelength NIR laser imaging-assisted dual-modal phototherapy. We opted for loading IR780 into polymeric Pluronic-F127-chitosan nanoformulation in order to overcome its hydrophobicity and toxicity and to allow functionalization with folic acid. The obtained nanocapsules show temperature-dependent swelling and spectroscopic behavior with favorable size distribution for cellular uptake at physiological temperatures, improved fluorescence properties and good stability. The fabricated nanocapsules can efficiently generate singlet oxygen in solution and are able to produce considerable temperature increase (46 °C) upon NIR laser irradiation. Viability assays on NIH-OVCAR-3 cells confirm the successful biocompatibilization of IR780 by encapsulating in Pluronic and chitosan polymers. NIR fluorescence imaging assays reveal the ability of folic-acid functionalized nanocapsules to serve as intracellular contrast agents and demonstrate their active targeting capacity against folate receptor expressing ovarian cancer cells (NIH-OVCAR-3). Consequently, the targeted nanocapsules show improved NIR laser induced phototherapeutic performance against NIH-OVCAR-3 cells compared to free IR780. We anticipate that this class of nanocapsules holds great promise as theranostic agents for application in image-guided dual PDT-PTT and imaging assisted surgery of ovarian cancer.

Cancer Nanotheranostics: A Nanomedicinal Approach for Cancer Therapy and Diagnosis

The panorama of cancer treatment has taken a considerable leap over the last decade with the advancement in the upcoming novel therapies combined with modern diagnostics. Nanotheranostics is an emerging science that holds tremendous potential as a contrivance by integrating therapy and imaging in a single probe for cancer diagnosis and treatment thus offering the advantage like tumor-specific drug delivery and at the same time reduced side effects to normal tissues. The recent surge in nanomedicine research has also paved the way for multimodal theranostic nanoprobe towards personalized therapy through interaction with a specific biological system. This review presents an overview of the nano theranostics approach in cancer management and a series of different nanomaterials used in theranostics and the possible challenges with future directions.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

Magnetically targeted erythrocyte membrane coated nanosystem for synergistic photothermal/chemotherapy of cancer

Combination photothermal therapy (PTT)/chemotherapy has become an emerging cancer treatment strategy in recent years. However, one of the important challenges in the development of nanomedicines is escaping immune recognition and the phagocytosis by the reticuloendothelial system (RES) to ultimately maximize tumor accumulation. In this work, a cell membrane-coated magnetically targeted drug delivery nanosystem was developed for synergistic PTT/chemotherapy of cancer. Importantly, this nanosystem can cleverly escape identification and clearance from the immune system, effectively prolong the blood circulation time and accurately accumulate in the target tumor tissues. This provides a new strategy to realize extraordinary antitumor effect by a unique design with cell membrane cloaking, magnetic targeting, drug delivery and synergistic PTT/chemotherapy.

Using copper sulfide nanoparticles as cross-linkers of tumor microenvironment responsive polymer micelles for cancer synergistic photo-chemotherapy

Photo-chemotherapy presents promising therapeutic effects in cancer treatment. Photo-thermal and chemotherapeutic agents are generally delivered independently or jointly by drug carriers, such as polymer micelles. A polymer micelle is one type of widely researched drug carrier. However, there is a disassembly risk for polymer micelles under excessive dilution in blood circulation, leading to the premature release of payloads from the micelles and finally resulting in undesirable toxic side effects. Herein, amino-PEG decorated copper sulfide nanoparticles (CuS NPs) with photothermal effect were applied as a cross-linker to enhance polymeric micelles' stability and to provide photothermal therapy in the meanwhile. The micelles were prepared using a pH/reductive responsive polymer, poly(ε-caprolactone)-ss-poly(2-(diisopropylamino)ethyl methacrylate/glycidyl methacrylate/2-methylacrylloxyethyl phosphorylcholine (PCL-SS-P(DPA/GMA/MP)), abbreviated as DGM. Cross-linked micelles (DGM-CuS) exhibited high photothermal transformation efficiency and excellent stability against dilution, as well as pH and redox responsive drug release. Under near-infrared laser irradiation, the cell cytotoxicity of doxorubicin-loaded micelles DGM-CuS@DOX and DGM-CuS@DOX-P (DGM-CuS@DOX modified by peptides) increased by 17.1 times and 69.2 times correspondingly compared to that without laser irradiation. All of the solid 4T1 tumors disappeared, and tumor metastases were merely observed in the major organs of the tumor-bearing mice after administration of DGM-CuS@DOX and DGM-CuS@DOX-P with irradiation. In this synergistic therapy system, CuS NPs play double roles of a photothermal agent and a micelle cross-linker. The strategy of utilizing nanoparticles as cross-linkers is newly reported, which offers new insight for combination therapy.

Theranostic Nanoparticles for Pancreatic Cancer Treatment

Pancreatic cancer is one of the low vascular permeable tumors with a high mortality rate. The five-year survival period is ~5%. The field of drug delivery is at its pace in developing unique drug delivery carriers to treat high mortality rate cancers such as pancreatic cancer. Theranostic nanoparticles are the new novel delivery carriers where the carrier is loaded with both diagnostic and therapeutic agents. The present review discusses various therapeutic and theranostic nanocarriers for pancreatic cancer.

Hsp90 inhibitor-loaded IR780 micelles for mitochondria-targeted mild-temperature photothermal therapy in xenograft models of human breast cancer

Mitochondria-targeted mild-temperature photothermal therapy (MT-PTT) is a promising strategy that can maximize anticancer effects and reduce adverse reactions. Here, a novel photosensitizer with mitochondrial targeting based on IR780 iodide and heat shock protein 90 inhibitor (BIIB021), which can passively accumulate in MCF-7 cells and achieve effective MT-PTT effect is synthesized. The prepared PEG-IR780-BIIB021 nano-micelles possess considerable biocompatibility and biological stability, with an encapsulation efficiency of about 84% for BIIB021. They can selectively enrich in mitochondria, and release BIIB021 after NIR irradiation to reduce cell tolerance to heat, thereby reducing the mitochondrial membrane potential and rapidly affecting key intrinsic apoptotic factors (Cyt-C, Caspase-9, Bcl-2 and Bax) to achieve the effect of MT-PTT. It is believed that mitochondria-targeted MT-PTT generated by the PEG-IR780-BIIB021 nano-micelles is a promising therapeutic strategy in clinical practice.

All-in-one mitochondria-targeted NIR-II fluorophores for cancer therapy and imaging

Small-molecule subcellular organelle-targeting theranostic probes are crucial for early disease diagnosis and treatment. The imaging window of these molecules is mainly focused on the visible and near-infrared region (below ∼900 nm) which limits the tissue penetration depth and therapeutic effects. Herein, a novel NIR-II small-molecule probe H4–PEG-Glu with a thiopyrylium cation was synthesized. H4–PEG-Glu not only can quickly and effectively image mitochondria in acute myeloid leukemia (AML) cells, and induce G₀/G₁ phase arrest by the intrinsic mitochondrial apoptosis pathway w/o irradiation, but also exhibit moderate cytotoxicity against AML cancer cells in a dose dependent-manner without laser irradiation. The THP-1 cells treated with H4–PEG-Glu upon NIR laser irradiation showed enhanced chemo- and photothermal therapy (CPTT) with 93.07% ± 6.43 apoptosis by Annexin V staining. Meanwhile, H4–PEG-Glu displayed high synergistic CPTT effects in vivo, as well as specific NIR-II tumor imaging in AML patient derived PDX mouse models for the first time. Our work lays down a solid foundation for designing small-molecule NIR-II mitochondria-selective theranostic probes.

Small-molecule subcellular organelle-targeting theranostic probes are crucial for early disease diagnosis and treatment.

Nanomaterial-Based Tumor Photothermal Immunotherapy

In recent years, photothermal therapy (PTT) particularly nanomaterial-based PTT is a promising therapeutic modality and technique for cancer tumor ablation. In addition to killing tumor cells directly through heat, PTT also can induce immunogenic cell death (ICD) to activate the whole-body anti-tumor immune response, including the redistribution and activation of immune effector cells, the expression and secretion of cytokines and the transformation of memory T lymphocytes. When used in combination with immunotherapy, the efficacy of nanomaterial-based PTT can be improved. This article summarized the mechanism of nanomaterial-based PTT against cancer and how nanomaterial-based PTT impacts the tumor microenvironment and induces an immune response. Moreover, we reviewed recent advances of nanomaterial-based photothermal immunotherapy and discussed challenges and future outlook.

Assessing the Combinatorial Chemo-Photothermal Therapy Mediated by Sulfobetaine Methacrylate-Functionalized Nanoparticles in 2D and 3D In Vitro Cancer Models

Combinatorial cancer therapies mediated by nanomaterials can potentially overcome the limitations of conventional treatments. These therapies are generally investigated using 2D in vitro cancer models, leading to an inaccurate screening. Recently, 3D in vitro spheroids have emerged in the preclinical testing stage of nanomedicines due to their ability to mimic key features of the in vivo solid tumors. Investigate the chemo-photothermal therapy mediated by Doxorubicin and IR780 loaded sulfobetaine methacrylate functionalized nanoparticles, for the first time, using monolayers of cancer cells and spheroids. In the 2D cancer models, the nanomaterials' mediated photothermal therapy, chemotherapy, and chemo-photothermal therapy reduced cancer cells' viability to about 58%, 29%, and 1%, respectively. Interestingly, when the nanomaterials' mediated photothermal therapy is tested on 3D spheroids, no cytotoxic effect is noticed. In contrast, the nanostructures' induced chemotherapy decreased spheroids' viability to 42%. On the other hand, nanomaterials' mediated chemo-photothermal therapy diminished spheroids' viability to 16%, being the most promising therapeutic modality. These results demonstrate the importance of using 3D spheroids during the in vitro screening of single/combinatorial therapies mediated by nanomaterials.

Designer Nanoparticles as Robust Superlubrication Vectors

Phosphatidylcholine lipid bilayers or liposomes at interfaces in aqueous environments can provide extremely efficient lubrication. This is attributed to the hydration lubrication mechanism acting at the highly hydrated phosphocholine-headgroup layers exposed at the outer surface of each bilayer. Micelles exposing such phosphocholine groups could be an attractive alternative to liposomes due to their much easier preparation and structure control, but all studies to date of surfactant micelles have revealed that at relatively low normal stresses the surface layers rupture and friction increases abruptly. Here, we examine surface interactions between three kinds of phosphocholine-exposing micelles with different designed structures: single-tail surfactant micelles, homo-oligomeric micelles, and block copolymer micelles. Normal and shear forces between mica surfaces immersed in solutions of these micelles were measured using a surface force balance. The adsorbed layers on the mica were imaged using atomic force microscope, revealing surface structures ranging from wormlike to spherical micelles. The block copolymer micelles showed relatively low coverage arising from their stabilizing corona and consequently poor lubrication (μ ∼ 10-1). In contrast, the surfactant and homo-oligomeric micelles fully covered the mica surface and demonstrated excellent lubrication (μ ∼ O(10-3)). However, while the boundary layer of single-tailed surfactant micelles degraded under moderate pressure, the homo-oligomeric micellar boundary layer was robust at all applied contact pressures in our study (up to about 5 MPa). We attribute the difference to the much greater energy required to remove a homo-oligomeric molecule from its micelle, resulting in far greater stability under pressure and shear.

Applications of Inorganic Nanomaterials in Photothermal Therapy Based on Combinational Cancer Treatment

BACKGROUND

Cancer is one of the major causes of death and is difficult to cure using existing clinical therapies. Clinical cancer treatments [such as surgery, chemotherapy (CHT), radiotherapy (RT) and immunotherapy (IT)] are widely used but they have limited therapeutic effects and unavoidable side effects. Recently, the development of novel nanomaterials offers a platform for combinational therapy (meaning a combination of two or more therapeutic agents) which is a promising approach for cancer therapy. Recent studies have demonstrated several types of nanomaterials suitable for photothermal therapy (PTT) based on a near-infrared (NIR) light-responsive system. PTT possesses favorable properties such as being low in cost, and having high temporospatial control with minimal invasiveness. However, short NIR light penetration depth limits its functions.

METHODS

In this review, due to their promise, we focus on inorganic nanomaterials [such as hollow mesoporous silica nanoparticles (HMSNs), tungsten sulfide quantum dots (WS2QDs), and gold nanorods (AuNRs)] combining PTT with CHT, RT or IT in one treatment, aiming to provide a comprehensive understanding of PTT-based combinational cancer therapy.

RESULTS

This review found much evidence for the use of inorganic nanoparticles for PTT-based combinational cancer therapy.

CONCLUSION

Under synergistic effects, inorganic nanomaterial-based combinational treatments exhibit enhanced therapeutic effects compared to PTT, CHT, RT, IT or PDT alone and should be further investigated in the cancer field.

Integration of Indocyanine Green Analogs as Near-Infrared Fluorescent Carrier for Precise Imaging-Guided Gene Delivery

Codelivery of diagnostic probes and therapeutic molecules often suffers from intrinsic complexity and premature leakage from or degradation of the nanocarrier. Inspired by the "Y" shape of indocyanine green (ICG), the dye is integrated in an amphiphilic lipopeptide (RNF). The hydrophilic segment is composed of arginine-rich dendritic peptides, while cyanine dyes are modified with two long carbon chains and employed as the hydrophobic moiety. They are linked through a disulfide linkage to improve the responsivity in the tumor microenvironment. After formulation with other lipopeptides at an optimized ratio, the theranostic system (RNS-2) forms lipid-based nanoparticles with slight positive zeta potential enabling efficient condensation of DNA. The RNS-2 displays glutathione responded gene release, activatable fluorescence recovery, and up to sevenfold higher in vitro transfection than Lipofectamine 2000. Compared with a Cy3 and Cy5 labeled fluorescence resonance energy transfer indicator for gene release, the "turn-on" indocyanine green analogs exhibit longer emission wavelength and better positive correlation with the dynamic processes of gene delivery. More importantly, the RNS-2 system enables efficient near infrared imaging guided gene transfer in tumor-bearing mice and thus provides more precise and accurate information on location of the cargo gene and synthesized carriers.

Light-triggered selective ROS-dependent autophagy by bioactive nanoliposomes for efficient cancer theranostics

Light-responsive nanoliposomes are being reported to induce cancer cell death through heat and reactive oxygen species (ROS). Nanoliposomes (CIR NLPs) encapsulating a near-infrared (NIR) light-sensitive dye, IR780, and a bioactive chlorophyll-rich fraction of Anthocephalus cadamba (CfAc) were synthesized and characterized. These CIR NLPs, when activated by NIR light, displayed localized synergistic cancer cell death under in vitro and in vivo conditions. We demonstrated a NIR light-mediated release of CfAc in cancer cells. The bioactive CfAc was selective in causing ROS generation (leading to autophagic cell death) in cancer cells, while normal healthy cells were unaffected. An increase in the intracellular ROS leading to enhanced lipidation of microtubule-associated protein light chain 3 (LC3-II) was observed only in cancer cells, while normal cells showed no increase in either ROS or LC3-II. In vivo analysis of CIR NLPs in an orthotopic mouse model showed better anti-tumorigenic potential through a combined effect (i.e. via heat and CfAc). We reported for the first time induction of selective and localized, bioactive phyto fraction-mediated autophagic cancer cell death through an NIR light trigger. The synergistic activation of ROS-mediated autophagy by light-triggered nanoliposomes can be a useful strategy for enhancing the anticancer potential of combinational therapies.

Self-assembly of paramagnetic amphiphilic copolymers for synergistic therapy

Theranostic nanoparticles composed of amphiphilic paramagnetic polymers are assembled for dual mode imaging and synergistic therapy.

Long circulating photoactivable nanomicelles with tumor localized activation and ROS triggered self-accelerating drug release for enhanced locoregional chemo-photodynamic therapy

Although chemo-photodynamic therapy demonstrates promising synergetic therapeutic effect in malignant cancers, the currently available nanocarriers offer the limited capabilities for selective toxicity, drug release and tumor penetration. Herein, we developed photoactivatable nanomicelles, which are constructed by self-assembling of poly (ethylene glycol) (PEG)-stearamine (C18) conjugate (PTS) with a ROS-sensitive thioketal linker (TL) and co-loaded with doxorubicin (DOX) and photosensitizer pheophorbide A (PhA), for enhanced locoregional chemo-photodynamic therapy. Upon accumulation in tumor region, the resulting PTS nanomicelles loaded with Dox and PhA (PTS-DP) demonstrated reactive oxygen species (ROS) cascade responsive release of the DOX and PhA loaded inside. Initial intracellular release of DOX and PhA from the PTS-DP was triggered by the intrinsic presence of endogenous ROS within cancer cells. Furthermore, upon laser irradiation on the tumor region, enhanced singlet oxygen (¹O₂) was generated by PhA released initially in cancer cells, which in turns accelerated the cytoplasmic release of DOX through rapid dissociation of nanomicelles. The gradual elevation of local ROS level generated by light-activated PhA subsequent ROS-triggered release of DOX synergistically inhibited tumor growth and enhances the anti-tumor immunity. Findings of our study suggested that ROS-sensitive PTS nanomicelles could be a promising and innovative nanocarrier for locoregional chemo-photodynamic therapy.

A bottlebrush-architectured dextran polyprodrug as an acidity-responsive vector for enhanced chemotherapy efficiency

Compared to normal tissues, unique conditions in the tumor microenvironment, such as a lower pH, can induce accurate release of a drug into specific lesions. This strategy provides an efficient approach to overcome the issues of unexpected drug leakage and poor circulation stability, thereby reducing the side effects and enhancing the effect of cancer treatment. In this study, we designed a class of acid activatable supramolecular nano-prodrugs (DOM@DOX) with a bottlebrush architecture based on the dextran (DEX) polysaccharide, which connects with a hydrophilic polyethylene glycol chain by atom transfer radical polymerization and further conjugates with an anticancer drug doxorubicin (DOX) at the backbone of the copolymer via an acidity-responsive hydrazine bond. Furthermore, the DOM@DOX prodrug has a high drug loading up to 48 wt% for DOX, and the prodrug can maintain a stable nano-sized spherical shape in aqueous solution by a self-assembly strategy. In an acidic environment inside tumor cells, the hydrazine bond of the prodrug breaks, leading to the release of DOX from parental micelles. Owing to the small size of the carrier, the prodrug exhibits good intratumoral permeability, good circulation stability and significant tumor suppression efficiency in tumor-bearing mouse models, which is beneficial for the development of new generation nanomedicine for enhanced chemotherapy.

Recent Advances in Nanomaterials-Based Chemo-Photothermal Combination Therapy for Improving Cancer Treatment

Conventional chemotherapy for cancer treatment is usually compromised by shortcomings such as insufficient therapeutic outcome and undesired side effects. The past decade has witnessed the rapid development of combination therapy by integrating chemotherapy with hyperthermia for enhanced therapeutic efficacy. Near-infrared (NIR) light-mediated photothermal therapy, which has advantages such as great capacity of heat ablation and minimally invasive manner, has emerged as a powerful approach for cancer treatment. A variety of nanomaterials absorbing NIR light to generate heat have been developed to simultaneously act as carriers for chemotherapeutic drugs, contributing as heat trigger for drug release and/or inducing hyperthermia for synergistic effects. This review aims to summarize the recent development of advanced nanomaterials in chemo-photothermal combination therapy, including metal-, carbon-based nanomaterials and particularly organic nanomaterials. The potential challenges and perspectives for the future development of nanomaterials-based chemo-photothermal therapy were also discussed.

Tumor-Targeting NIRF NanoGUMBOS with Cyclodextrin-Enhanced Chemo/Photothermal Antitumor Activities

The near-infrared fluorescent (NIRF) dye, IR780, is recognized as a promising theranostic agent and has been widely investigated for imaging, chemotherapeutic, and phototherapeutic applications. However, its poor photostability and nonselective toxicities toward both cancer and normal cells limit its biological applications. Herein, we introduce the use of GUMBOS (a group of uniform materials based on organic salts) developed through counter-anion exchange with IR780 and subsequent nanomaterials (nanoGUMBOS) formed by complexation with cyclodextrin (CD) for enhanced chemo/photothermal therapy. Such CD-based nanoGUMBOS display improved aqueous stability, photostability, and photothermal effects relative to traditional IR780. The examination of in vitro cytotoxicity reveals that CD-based nanoGUMBOS are selectively toxic toward cancer cells and exhibit synergistically enhanced cytotoxicity toward cancer cells upon NIR laser irradiation. Additionally, in vivo NIRF imaging demonstrated selective accumulation of these nanoGUMBOS within the tumor site, indicating tumor-targeting properties. Further in vivo therapeutic study of these CD-based nanoGUMBOS suggests excellent chemo/photothermal antitumor effects. Using these studies, we herein demonstrate a promising strategy, via conversion of IR780 into nanoGUMBOS, that can be used for improved theranostic cancer treatment.

Codelivery of doxorubicin and camptothecin by dual-responsive unimolecular micelle-based β-cyclodextrin for enhanced chemotherapy

Tumor microenvironment (TME)-induced drug delivery technology is a promising strategy for improving low drug accumulation efficiency, short blood circulation and weak therapeutic effect. In this work, a dual-responsive (reduction- and pH-responsive) polyprodrug nanoreactor based on β-cyclodextrin (β-CD) was constructed for combinational chemotherapy. Specifically, the dual-responsive star polymeric prodrug was synthesized by atom transfer radical polymerization (ATRP) based on a starburst initiator of β-CD-Br. The obtained polyprodrug contained a hydrophilic chain of poly-(ethylene glycol) methyl ether methacrylate (POEGMA) and a hydrophobic part of camptothecin (CPT) prodrug and poly[2-(diisopropylamino)ethyl methacrylate] (PDPA), denoted as β-CD-PDPA-POEGMA-PCPT (CCDO for short). The obtained CCDO could form stable unimolecular micelles, which could be efficiently internalized by cancer cells. To enhance the curative effect, the anticancer agent doxorubicin (DOX) could be encapsulated into the hydrophobic cavity of the CCDO by hydrophobic-hydrophobic interaction. In vitro drug release studies showed that the obtained CCDO/DOX micelles controlled the release of active CPT and DOX occurring in a reductive environment and at low pH. In vitro cytotoxicity results suggested that the anticancer efficacy of dual-responsive CCDO/DOX micelles was superior to that of CCDO micelles. In addition, in vivo results verified good blood compatibility of the unimolecular micelles. This integrated dual-responsive drug delivery system may solve the low drug loading and poor controlled release problems found in traditional polymer-based drug carriers, providing an innovative and promising route for cancer therapy.

Hydrophobic IR780 loaded sericin nanomicelles for phototherapy with enhanced antitumor efficiency

The near-infrared dye, IR780 iodide, has been utilized in photodynamic therapy (PDT) and photothermal therapy (PTT). However, the hydrophobicity and photosensitivity of IR780 limit its further applications in biomedical fields. Herein, the hydrophilic sericin was modified with hydrophobic cholesterol to form an amphiphilic macromolecular conjugate (Ser-Chol). The tumor-targeting agent, folic acid (FA), was further linked to the conjugate (FA-Ser-Chol). The IR780 could be encapsulated into such amphiphilic macromolecule to form stable micelles (FA-Ser-Chol/IR780) by self-assembly, and the solubility and photo-stability of IR780 were greatly improved. The FA-Ser-Chol/IR780 micelles could be efficiently absorbed by FA-positive gastric cancer cells (BGC-823) through FA receptors, while the uptake micelles showed remarkable PDT and PTT cytotoxicity towards BGC-823 cells under laser irradiation of 808 nm. Therefore, FA-Ser-Chol micelles may serve as a promising IR780 carrier for PDT and PTT therapy.

IR820-loaded PLGA nanoparticles for photothermal therapy of triple-negative breast cancer

Triple-negative breast cancer (TNBC) accounts for 15-25% of breast cancer cases and lacks expression of the three most common receptors seen on other subtypes of breast cancer. This lack of expression makes TNBC unsusceptible to currently available targeted or hormonal therapies, so new treatment strategies are desperately needed. Photothermal therapy (PTT), which utilizes nanoparticles (NPs) embedded in tumors as exogenous energy absorbers to convert externally applied near-infrared (NIR) light into heat to ablate cancer cells, has shown promise as an alternative strategy. However, it typically uses gold-based NPs that will remain in the body for extended period of time with unknown long-term health effects. To enable PTT with biodegradable, polymeric NPs, we encapsulated the NIR-absorbing dye IR820 in poly(lactic-co-glycolic acid) (PLGA) NPs. We characterized the physicochemical properties of these IR820-loaded PLGA NPs and evaluated their performance as PTT agents using both in vitro and in vivo models of TNBC. The results demonstrate that these NPs are potent mediators of PTT that induce cell death primarily through apoptosis to effectively hinder the growth of TNBC tumors. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1702-1712, 2019.

Near-infrared imaging of diseases: A nanocarrier approach

Developments in fluorescence imaging, brought popularity to near infrared (NIR) imaging with far-red and NIR fluorophores applied for biosensing and bioimaging in living systems. Noninvasive NIR imaging gained popularity with the use of effective NIR dyes to obtain macroscopic fluorescence images. Several attributes of NIR dyes make them desirable agents, including high specificity, high sensitivity, minimized background interference, and the ability to easily conjugate with drug delivery systems. However, NIR dyes have some drawbacks and limitations, such as low solubility, low stability, and degradation. To overcome these issues, NIR dyes can be encapsulated in appropriate nanocarriers to achieve effective diagnosis, imaging, and therapy monitoring during surgery. Moreover, the vast majority of NIR dyes have photosensitizer features that can effectuate cancer treatment referred to as photodynamic therapy (PDT). In the near future, by combining NIR dyes with appropriate nanocarriers such as liposomes, polymeric micelles, polymeric nanoparticles, dendrimers, quantum dots, carbon nanotubes, or ceramic/silica based nanoparticles, the limitations of NIR dyes can be minimized or even effectively eliminated to form potential effective agents for imaging, therapy, and therapy monitoring of several diseases, particularly cancer.