Bioinspired Multifunctional Melanin-Based Nanoliposome for Photoacoustic/Magnetic Resonance Imaging-Guided Efficient Photothermal Ablation of Cancer

Coordination-induced exfoliation to monolayer Bi-anchored MnB2 nanosheets for multimodal imaging-guided photothermal therapy of cancer

Background: Rapid advance in biomedicine has recently vitalized the development of multifunctional two-dimensional (2D) nanomaterials for cancer theranostics. However, it is still challenging to develop new strategy to produce new types of 2D nanomaterials with flexible structure and function for enhanced disease theranostics. Method: We explore the monolayer Bi-anchored manganese boride nanosheets (MBBN) as a new type of MBene (metal boride), and discover their unique near infrared (NIR)-photothermal and photoacoustic effects, X-ray absorption and MRI imaging properties, and develop them as a new nanotheranostic agent for multimodal imaging-guided photothermal therapy of cancer. A microwave-assisted chemical etching route was utilized to exfoliate the manganese boride bulk into the nanosheets-constructed flower-like manganese boride nanoparticle (MBN), and a coordination-induced exfoliation strategy was further developed to separate the MBN into the dispersive monolayer MBBN by the coordination between Bi and B on the surface, and the B-OH group on the surface of MBBN enabled facile surface modification with hyaluronic acid (HA) by the borate esterification reaction in favor of enhanced monodispersion and active tumor targeting. Result: The constructed MBBN displays superior NIR-photothermal conversion efficiency (η=59.4%) as well as high photothermal stability, and possesses versatile imaging functionality including photoacoustic, photothermal, CT and T1 -wighted MRI imagings. In vitro and in vivo evaluations indicate that MBBN had high photothermal ablation and multimodal imaging performances, realizing high efficacy of imaging-guided cancer therapy. Conclusion: We have proposed new MBene concept and exfloliation strategy to impart the integration of structural modification and functional enhancement for cancer theranostics, which would open an avenue to facile fabrication and extended application of multifunctional 2D nanomaterials.

Glucose Oxidase-Instructed Traceable Self-Oxygenation/Hyperthermia Dually Enhanced Cancer Starvation Therapy

Cancer theranostics based on glucose oxidase (GOx)-induced starvation therapy has got more and more attention in cancer management. Herein, GOx armed manganese dioxide nanosheets (denoted as MNS-GOx) were developed as cancer nanotheranostic agent for magnetic resonance (MR)/photoacoustic (PA) dual-modal imaging guided self-oxygenation/hyperthermia dually enhanced starvation cancer therapy. The manganese dioxide nanomaterials with different morphologies (such as nanoflowers, nanosheets and nanowires) were synthesized by a biomimetic approach using melanin as a biotemplate. Afterwards, the manganese dioxide nanosheets (MNS) with two sides and large surface area were selected as the vehicle to carry and deliver GOx. The as-prepared MNS-GOx can perform the circular reaction of glucose oxidation and H2O2 decomposition for enhanced starvation therapy. Moreover, the catalytic activity of GOx could be further improved by the hyperthermia of MNS-GOx upon near-infrared laser irradiation. Most intriguingly, MNS-GOx could achieve "turn-on" MR imaging and "turn-off" PA imaging simultaneously. The theranostic capability of MNS-GOx was evaluated on A375 tumor-bearing mice with all tumor elimination. Our findings integrated molecular imaging and starvation-based synergistic cancer therapy, which provided a new platform for cancer nanotheranostics.

Recent advances in melanin-like nanomaterials in biomedical applications: a mini review

BACKGROUND

Melanins are a group of biopigments in microorganisms that generate a wide range of colorants. Due to their multifunctionality, including ultraviolet protection, radical scavenging, and photothermal conversion, in addition to their intrinsic biocompatibility, natural melanins and synthetic melanin-like nanomaterials have been suggested as novel nano-bio platforms in biomedical applications.

MAIN BODY

Recent approaches in the synthesis of melanin-like nanomaterials and their biomedical applications have briefly been reviewed. Melanin-like nanomaterials have been suggested as endogenous chromophores for photoacoustic imaging and radical scavengers for the treatment of inflammatory diseases. The photothermal conversion ability of these materials under near-infrared irradiation allows hyperthermia-mediated cancer treatments, and their intrinsic fluorescence can be an indicator in biosensing applications. Furthermore, catechol-rich melanin and melanin-like nanomaterials possess a versatile affinity for various functional organic and inorganic additives, allowing the design of multifunctional hybrid nanomaterials that expand their range of applications in bioimaging, therapy, theranostics, and biosensing.

CONCLUSION

Melanin-like natural and synthetic nanomaterials have emerged; however, the under-elucidated chemical structures of these materials are still a major obstacle to the construction of novel nanomaterials through bottom-up approaches and tuning the material properties at the molecular level. Further advancements in melanin-based medical applications can be achieved with the incorporation of next-generation chemical and molecular analytical tools.

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Recent Trends of the Bio-Inspired Nanoparticles in Cancer Theranostics

In recent years, various nanomaterials have emerged as an exciting tool in cancer theranostic applications due to their multifunctional property and intrinsic molecular property aiding effective diagnosis, imaging, and successful therapy. However, chemically synthesized nanoparticles have several issues related to the cost, toxicity and effectiveness. In this context, bio-inspired nanoparticles (NPs) held edges over conventionally synthesized nanoparticles due to their low cost, easy synthesis and low toxicity. In this present review article, a detailed overview of the cancer theranostics applications of various bio-inspired has been provided. This includes the recent examples of liposomes, lipid nanoparticles, protein nanoparticles, inorganic nanoparticles, and viral nanoparticles. Finally, challenges and the future scopes of these NPs in cancer therapy and diagnostics applications are highlighted.

A multifunctional nanoplatform based on MoS2-nanosheets for targeted drug delivery and chemo-photothermal therapy

Synergistic tumor treatment has recently attracted more and more attention due to its remarkable therapeutic effect. Herein, a multifunctional drug delivery system based on hyaluronic acid (HA) targeted dual stimulation responsive MoS₂ nanosheets (HA-PEI-LA-MoS₂-PEG, HPMP) for active interaction with CD44 receptor positive MCF-7 cells is reported. Melanin (Mel), a new type of photothermal agent and doxorubicin (DOX) are both loaded onto the HPMP nanocomposite and can be released by mild acid or hyperthermia. The prepared HPMP nanocomposite has a uniform hydrodynamic diameter (104 nm), a high drug loading (944.3 mg.g^-1 HPMP), a remarkable photothermal effect (photothermal conversion efficiency: 55.3%) and excellent biocompatibility. The DOX release from HPMP@(DOX/Mel) can be precisely controlled by the dual stimuli of utilizing the acidic environment in the tumor cells and external laser irradiation. Meanwhile, loading of Mel onto the surface can enhance the photothermal effect of the MoS₂ nanosheets. In vitro experiments showed that the HPMP@(DOX/Mel) nanoplatform could efficiently deliver DOX into MCF-7 cells and demonstrated enhanced cytotoxicity compared to that of the non-targeted nanoplatform. In vivo experiments in a breast cancer model of nude mice further confirmed that the HPMP@(DOX/Mel) significantly inhibited tumor growth under near infrared (NIR) laser irradiation, which is superior to any single therapy. In summary, this flexible nanoplatform, based on multi-faceted loaded MoS₂ nanosheets, exhibits considerable potential for efficient pH/NIR-responsive targeted drug delivery and chemo-photothermal synergistic tumor therapy.

A near-infrared light-controlled smart nanocarrier with reversible polypeptide-engineered valve for targeted fluorescence-photoacoustic bimodal imaging-guided chemo-photothermal therapy

Despite burgeoning development of nanoplatform made in the past few years, it remains a challenge to produce drug nanocarrier that enables requested on/off drug release. Thus, this study aimed to develop an ideal near-infrared light-triggered smart nanocarrier for targeted imaging-guided treatment of cancer that tactfully integrated photothermal therapy with chemotherapy to accurately control drug release time and dosage. Methods: This delivery system was composed of Ag₂S QD coating with dendritic mesoporous silica (DMSN), which acted as nanocarrier of doxorubicin localized inside pores. To provide the nanocarrier with controlled release capability, a polypeptide-engineered that structure was reversible to photothermal effect of Ag₂S QD, was covalently grafted to the external surface of drug-loaded DMSN. Results: This nanocarrier with the size of 40~60 nm had satisfactory biocompatibility and photothermal conversion efficiency up to 28.35%. Due to acidity-triggered charge reversal of polypeptide, which significantly extended circulation time and improved targeting ability, fluorescence and photoacoustic signals were still obvious at tumor site post-24 h by tail vein injection and chemo-photothermal synergistic therapy obviously enhanced antitumor efficacy. Mild PTT with multiple short-term exposures not only reduced the side effect of overdose drug but also avoided skin damage caused by long-term irradiation. Conclusion: By adjusting irradiation time and on/off cycle, multiple small amount local drug release reduced the side effect of overdose drug and skin damage. This novel approach provided an ideal near-infrared light-triggered nanocarrier with accurate control of area, time, and especially dosage.

Tumor Targeting Strategies of Smart Fluorescent Nanoparticles and Their Applications in Cancer Diagnosis and Treatment

Advantages such as strong signal strength, resistance to photobleaching, tunable fluorescence emissions, high sensitivity, and biocompatibility are the driving forces for the application of fluorescent nanoparticles (FNPs) in cancer diagnosis and therapy. In addition, the large surface area and easy modification of FNPs provide a platform for the design of multifunctional nanoparticles (MFNPs) for tumor targeting, diagnosis, and treatment. In order to obtain better targeting and therapeutic effects, it is necessary to understand the properties and targeting mechanisms of FNPs, which are the foundation and play a key role in the targeting design of nanoparticles (NPs). Widely accepted and applied targeting mechanisms such as enhanced permeability and retention (EPR) effect, active targeting, and tumor microenvironment (TME) targeting are summarized here. Additionally, a freshly discovered targeting mechanism is introduced, termed cell membrane permeability targeting (CMPT), which improves the tumor-targeting rate from less than 5% of the EPR effect to more than 50%. A new design strategy is also summarized, which is promising for future clinical targeting NPs/nanomedicines design. The targeting mechanism and design strategy will inspire new insights and thoughts on targeting design and will speed up precision medicine and contribute to cancer therapy and early diagnosis.

Listening to tissues with new light: recent technological advances in photoacoustic imaging

Photoacoustic tomography (PAT), or optoacoustic tomography, has achieved remarkable progress in the past decade, benefiting from the joint developments in optics, acoustics, chemistry, computing and mathematics. Unlike pure optical or ultrasound imaging, PAT can provide unique optical absorption contrast as well as widely scalable spatial resolution, penetration depth and imaging speed. Moreover, PAT has inherent sensitivity to tissue's functional, molecular, and metabolic state. With these merits, PAT has been applied in a wide range of life science disciplines, and has enabled biomedical research unattainable by other imaging methods. This Review article aims at introducing state-of-the-art PAT technologies and their representative applications. The focus is on recent technological breakthroughs in structural, functional, molecular PAT, including super-resolution imaging, real-time small-animal whole-body imaging, and high-sensitivity functional/molecular imaging. We also discuss the remaining challenges in PAT and envisioned opportunities.

Folate-Targeted and Oxygen/Indocyanine Green-Loaded Lipid Nanoparticles for Dual-Mode Imaging and Photo-sonodynamic/Photothermal Therapy of Ovarian Cancer in Vitro and in Vivo

We have successfully fabricated versatile folate-targeted and oxygen/indocyanine green-loaded lipid nanoparticles (FA-OINPs) for dual-mode imaging-guided therapy in ovarian cancer cells and subcutaneous xenograft models. FA-OINPs were demonstrated to have great potential as superb contrast agents to enhance ultrasound and photoacoustic (US/PA) imaging We have successfully fabricated versatile folate-targeted and oxygen/indocyanine green-loaded lipid nanoparticles (FA-OINPs) for dual-mode imaging-guided therapy in ovarian cancer cells and subcutaneous xenograft models. FA-OINPs were demonstrated to have great potential as superb contrast agents to enhance ultrasound and photoacoustic (US/PA) imaging in vitro and in vivo. Confocal laser scanning microscopy and flow cytometry analysis verified that FA-OINPs could specifically target SKOV3 ovarian cancer cells and be endocytosed with a remarkable efficiency. Compared with other therapeutic options, FA-OINPs exhibited an excellent therapeutic outcome after exposure to laser and ultrasound. The MTT assay and flow cytometry analysis confirmed that cytotoxicity effects and apoptosis/necrosis rates were significantly increased. The fluorescence microscopy and fluorescence microplate reader detection validated that the generation of intracellular reactive oxygen species (ROS) was dramatically improved. Immunohistochemical analyses of tumor tissues demonstrated the enhanced tumor apoptosis, the decreased vascular endothelial growth factor (VEGF) and microvascular density (MVD) expression, and the decreased expression of CD68 after treatment. The presented results suggest that photo-sonodynamic/photothermal mediated FA-OINPs could provide a promising strategy for synergistic therapy in ovarian cancer with the guidance of US/PA dual-mode imaging.

Polydopamine-modified dual-ligand nanoparticles as highly effective and targeted magnetic resonance/photoacoustic dual-modality thrombus imaging agents

Background

Platelet activation and subsequent aggregation are the initial stages of thrombosis. A molecular probe that specifically targets activated platelets and remains retained under high shear stress in vivo can enhance the imaging effect to achieve early and accurate diagnosis.

Methods and materials

In this study, we constructed nanoparticles (NPs) using polydopamine to carry two peptides that simultaneously bind integrin αIIbβ3 and P-selectin on activated platelets to enhance the targeting of NPs to thrombus.

Results

The targeting specificity and binding stability of the NPs on red and white thrombi were demonstrated in vitro using a simulated circulatory device and the targeting effect of the NPs on mixed thrombus was studied by  magnetic resonance (MR)/photoacoustic (PA) dual-modality imaging in vivo. NPs that were surface modified with both peptides have higher selectivity and retention to red and white thrombi in vitro than NPs with a single or no peptide, and the targeting effect was closely related to the number and distribution of activated platelets as well as the structure and type of thrombus. The NPs also have MR/PA dual-modality imaging functionality, significantly enhancing the imaging of mixed thrombus in vivo.

Conclusion

These dual-targeted NPs have improved targeting specificity and binding stability to different thrombi under high shear stress and are beneficial for the early diagnosis of thrombosis.

Molecular Targeting-Mediated Mild-Temperature Photothermal Therapy with a Smart Albumin-Based Nanodrug

Photothermal therapy (PTT) usually requires hyperthermia >50 °C for effective tumor ablation, which inevitably induces heating damage to the surrounding normal tissues/organs. Moreover, low tumor retention and high liver accumulation are the two main obstacles that significantly limit the efficacy and safety of many nanomedicines. To solve these problems, a smart albumin-based tumor microenvironment-responsive nanoagent is designed via the self-assembly of human serum albumin (HSA), dc-IR825 (a cyanine dye and a photothermal agent), and gambogic acid (GA, a heat shock protein 90 (HSP90) inhibitor and an anticancer agent) to realize molecular targeting-mediated mild-temperature PTT. The formed HSA/dc-IR825/GA nanoparticles (NPs) can escape from mitochondria to the cytosol through mitochondrial disruption under near-infrared (NIR) laser irradiation. Moreover, the GA molecules block the hyperthermia-induced overexpression of HSP90, achieving the reduced thermoresistance of tumor cells and effective PTT at a mild temperature (<45 °C). Furthermore, HSA/dc-IR825/GA NPs show pH-responsive charge reversal, effective tumor accumulation, and negligible liver deposition, ultimately facilitating synergistic mild-temperature PTT and chemotherapy. Taken together, the NIR-activated NPs allow the release of molecular drugs more precisely, ablate tumors more effectively, and inhibit cancer metastasis more persistently, which will advance the development of novel mild-temperature PTT-based combination strategies.

Combined chemo/photothermal therapy based on mesoporous silica-Au core-shell nanoparticles for hepatocellular carcinoma treatment

Chemotherapy has been widely used for treatment to malignant cancer, such as hepatocellular carcinoma (HCC). Chemotherapeutic effect was not often efficient to achieve totally tumor ablation due to the poor cellular uptake and drug resistance. To address these problems, a novel nanoplatform was constructed based on nontoxic mesoporous silica nanoparticles (MSNs) for a combined chemo/photothermal therapy to enhance tumor cell accumulation and promote toxicity of chemotherapeutic drugs. Prepared MSNs were consisted of Au nanoshell for photothermal conversion and a first-line anti-HCC drug-sorafenib (SO) for chemotherapy. The SO-Au-MSNs could help SO accumulate more in hepatic cancer cells. Under near infrared irradiation, SO-Au-MSNs exerted a high cell inhibition rate which could be attributed to the enhanced toxicity of SO under hyperthermia and synergistic chemo/photothermal therapy. SO-Au-MSNs showed a good compatibility as well as efficient cell cytotoxicity. Overall, SO-Au-MSNs would be a promising candidate for further enhancing the antitumor effect on HCC.

IR780-based light-responsive nanocomplexes combining phase transition for enhancing multimodal imaging-guided photothermal therapy

Near-infrared (NIR) light-triggered photothermal therapy (PTT) has been widely applied for treating cancer. The combination of nanotechnology and NIR has shown great promise for promoting the efficacy of PTT. However, PTT alone could not completely ablate the tumors and easily causes tumor recurrence. To overcome this challenge, many studies have been performed to enhance PTT, including combining chemical therapy and radiotherapy, both of which have side effects on the body. To reduce the side effects and enhance PTT, a new infrared IR780-based nanocomplex combining liquid fluorocarbon perfluoropentane (PFP) has been synthesized for enhancing multimodal imaging-guided PTT. Under NIR irradiation, the size changes of PFP-loaded nanobubbles transforming into microbubbles allow ultrasound (US) imaging, showing boundaries and internal information of tumors. The breakup process and cascade reaction of phase transition can improve intratumoral permeation and retention of nanoparticles in nonmicrovascular tissue and damage the cell membranes of tumors, further enhancing PTT to kill tumor cells. The strong absorption in the NIR field of IR780-loaded NPs allows not only photoacoustic (PA) imaging but also NIR fluorescence (NIRF) imaging, which provides more anatomical information about tumors. This nanocomplex exhibits good biocompatibility and nontoxicity, strong PA/US/NIRF imaging contrast, excellent liquid-gas transition and a photothermal effect. This finding provides a new method to enhance multimodal imaging-guided cancer nanotheranostics.

State-of-the-Art Preclinical Photoacoustic Imaging in Oncology: Recent Advances in Cancer Theranostics

The optical imaging plays an increasing role in preclinical studies, particularly in cancer biology. The combined ultrasound and optical imaging, named photoacoustic imaging (PAI), is an emerging hybrid technique for real-time molecular imaging in preclinical research and recently expanding into clinical setting. PAI can be performed using endogenous contrast, particularly from oxygenated and deoxygenated hemoglobin and melanin, or exogenous contrast agents, sometimes targeted for specific biomarkers, providing comprehensive morphofunctional and molecular information on tumor microenvironment. Overall, PAI has revealed notable opportunities to improve knowledge on tumor pathophysiology and on the biological mechanisms underlying therapy. The aim of this review is to introduce the principles of PAI and to provide a brief overview of current PAI applications in preclinical research, highlighting also on recent advances in clinical translation for cancer diagnosis, staging, and therapy.

Liposome-based probes for molecular imaging: from basic research to the bedside

Molecular imaging is very important in disease diagnosis and prognosis. Liposomes are excellent carriers for different types of molecular imaging probes. In this work, we summarize current developments in liposome-based probes used for molecular imaging and their applications in image-guided drug delivery and tumour surgery, including computed tomography (CT), ultrasound imaging (USI), magnetic resonance imaging (MRI), positron emission tomography (PET), fluorescence imaging (FLI) and photoacoustic imaging (PAI). We also summarized liposome-based multimodal imaging probes and new targeting strategies for liposomes. This work will offer guidance for the design of liposome-based imaging probes for future clinical applications.

Mitochondria-Targeted and Ultrasound-Activated Nanodroplets for Enhanced Deep-Penetration Sonodynamic Cancer Therapy

Sonodynamic therapy (SDT), a promising alternative for cancer therapy, utilizes a sonosensitizer combined with ultrasound (US) irradiation to damage tumor cells/tissues for therapeutic purposes. The ability of sonosensitizers to specifically accumulate in tumor cells/tissues could greatly influence their therapeutic efficiency. In this work, we report the use of US-activated sonosensitizer (IR780)-based nanodroplets (IR780-NDs) for SDT, which provide numerous benefits for killing cancer cells compared with traditional methods. For instance, IR780-NDs showed effective surface-to-core diffusion both in vitro and in vivo. In the presence of US, the acoustic droplet vaporization (ADV) effect significantly assisted the conveyance of IR780-NDs from the circulatory system to tumor regions, and the acoustic wave force also increased the penetration depth within tumor tissues. Furthermore, IR780-NDs possesses mitochondrial targeting capabilities, which improves the precision and accuracy of SDT delivery. During the in vitro assessment, the overproduction of reactive oxygen species (ROS) was observed following mitochondrial targeting, which rendered cancer cells more susceptible to ROS-induced apoptosis. Additionally, IR780-ND is a suitable candidate for photoacoustic and fluorescence imaging and can also enhance US imaging because of the ADV-generated bubbles, which provides the potential for SDT guidance and monitoring. Therefore, with combined modalities, IR780-NDs can be a promising theranostics nanoplatform for cancer therapy.

Construction of a biodegradable, versatile nanocarrier for optional combination cancer therapy

A novel biodegradable versatile nanocarrier (FA-CM) was fabricated based on the self-assembly of delaminated CoAl-layered double hydroxides (LDHs) and manganese dioxide (MnO₂) for optional combination cancer therapy. Biodegradation, versatility, targeting, bioimaging, in vitro cytotoxicity and in vivo antitumor efficacy were evaluated. The results showed that FA-CM could not only be effectively degraded into Co²⁺, Al³⁺ and Mn²⁺ to overcome the long-term toxic side effects, but also successfully load any positive-charged, negative-charged, hydrophilic, and hydrophobic drug, meeting the critical requirement of versatile nanocarrier. Meanwhile, the presence of FA led to the higher uptake efficiency, cytotoxicity, and excellent fluorescence imaging of FA-CM toward cancerous cells. In particular, FA-CM exhibited glutathione and pH dual-response drug release, avoiding any premature leakage and side effects. The applicability of the FA-CM was determined by co-loading hydrophilic (doxorubicin (DOX)) and hydrophobic drug (paclitaxel (PTX)) for synergistic combination chemotherapy. In vitro cytotoxicity evaluation and a xenograft tumor model of hepatoma showed that this combination exhibited more efficient anticancer effects compared with either free drug alone or the corresponding cocktail solutions. Especially, the ratios of DOX and PTX loaded on FA-CM could be tuned as needed. A powerful approach is provided for the design and preparation of a biodegradable versatile nanocarrier with targeted ability and excellent biocompatibility, which can be potentially applied in clinical practice and medical imaging. STATEMENT OF SIGNIFICANCE: Drug delivery nanocarriers that can transport an effective dosage of drug molecules to targeted cells and tissues have been extensively designed to overcome the adverse side effects and low effectiveness of conventional chemotherapy. However, lack of biodegradability and versatility existing in majority of nanocarriers limit their further clinical applications. Thus, constructing a novel biodegradable versatile nanocarrier that can carry various types of drugs, is in urgent need and more suitable for commercial production and clinical use. In this study, we developed a novel biodegradable versatile nanocarrier (FA-CM) based on the self-assembly of delaminated CoAl-layered double hydroxides (LDHs) and manganese dioxide (MnO₂) for optional combination cancer therapy. This work provides a new strategy for constructing versatile biodegradable platform for targeted drug delivery, which would have broad applications in cancer theranostics.

Dual-functional melanin-based nanoliposomes for combined chemotherapy and photothermal therapy of pancreatic cancer

Pancreatic cancer, one of the most common gastrointestinal tract cancers, leads to a high mortality rate of over 80% among patients. Conventional chemotherapy with gemcitabine (GEM) is undesirable due to the lack of effective tumor accumulation. To improve the survival of pancreatic cancer patients and the therapeutic efficiency of chemotherapy, dual-functional melanin-based nanoliposomes loaded with GEM were synthesized in our study, which combined chemotherapy and photothermal therapy (PTT). Hypothermia caused by melanin under near-infrared (NIR) laser exerted detrimental damage on pancreatic cancer cells after the passive accumulation of nanoliposomes in the tumor sites. Besides, the temperature increase could enhance the release of GEM from the nanoliposomes by changing the structural integrity of the nanoliposomes. Therefore, a synergistic antitumor effect was achieved by loading the chemotherapy agent GEM and the photothermal agent melanin into the nanoliposomes. The findings in this study strongly support that melanin-based nanoliposomes could be a desirable strategy against pancreatic carcinoma.

GEM-Mel-Lip converted light to heat based on melanin after entering the tumor cells, and then the phospholipid fluidity was increased under the hyperthermia generated, resulting in the release of GEM.

Triple-Modal Imaging-Guided Chemo-Photothermal Synergistic Therapy for Breast Cancer with Magnetically Targeted Phase-Shifted Nanoparticles

Current nanodrug-based cancer therapy is susceptible to the problems of rapid clearance from circulation and limited therapeutic efficacy. Herein, we report a magnetically targeted and photothermal-triggered drug release nanotheranostics system based on superparamagnetic iron oxide (Fe₃O₄), IR780, doxorubicin (DOX), and perfluoropentane (PFP) entrapped poly-lactide- co-glycolide (PLGA) nanoparticles (IR780/Fe₃O₄@PLGA/PFP/DOX NPs) for triple-modal imaging-guided synergistic therapy of breast cancer. In this work, IR780 and Fe₃O₄ convert light into heat, which triggers DOX release from IR780/Fe₃O₄@PLGA/PFP/DOX NPs and a phase-shift thermoelastic expansion of PFP; this procedure further accelerates the DOX release and tissue extrusion deformation. Fe₃O₄ NPs also serve as the target moiety by an external magnet directed to the tumor. Specifically, the IR780/Fe₃O₄@PLGA/PFP/DOX NPs can be used for triple-modal imaging, including near infrared fluorescence, magnetic resonance, and ultrasound. Furthermore, the antitumor therapy studies reveal the extraordinary performance of IR780/Fe₃O₄@PLGA/PFP/DOX NPs in magnetically targeted synergistic chemo-photothermal therapy of cancer. Therefore, the multifunctional IR780/Fe₃O₄@PLGA/PFP/DOX NPs guided by the magnetic field show a great potential for cancer theranostics.

Nanosonosensitizers for Highly Efficient Sonodynamic Cancer Theranostics

Background: Multifunctional nanoplatforms with diagnostic-imaging and targeted therapeutic functionality (theranostics) are of great interest in the field of precision nanomedicine. The emerging sonodynamic therapy (SDT) combined with sonosensitizers under the guidance of photoacoustic (PA) imaging is highly expected to accurately eliminate cancer cells/tissue. Methods: Unique core/shell-structured theranostic FA-HMME-MNPs-PLGA nanoparticles (FHMP NPs, FA: folate, HMME: hematoporphyrin monomethyl ether, MNPs: melanin nanoparticles, PLGA: poly (lactic-co-glycolic) acid) were constructed by the integration of MNPs (for PA imaging) in the core and HMME in the shell for enhanced PA imaging-guided SDT, which were further functionalized with a tumor-targeting ligand, FA. The PA imaging-guided SDT was systematically and successfully demonstrated both in vitro and in vivo. The high biosafety of FHMP NPs was also systematically evaluated. Results: The synthesized FHMP NPs with a broad optical absorption not only possess high PA-imaging contrast enhancement capability but also exhibit significant SDT efficiency. Importantly, such a PLGA based nanoplatform improved light stability of HMME, enhancing sonodynamic performance and facilitated delivery of MNPs to the tumor region. Meanwhile, a combined effect between HMME and MNPs was discovered and verified. Furthermore, a sonosensitizer assisted by ultrasound irradiation engenders reactive oxygen species (ROS)-mediated cytotoxicity toward tumor cells/tissue. Both in vitro cell-level and systematic in vivo xenograft evaluations on tumor-bearing mice demonstrated that the selective killing effect of ROS on tumor cells was assisted by FHMP NPs, which played an active role in the suppression of tumor growth with high biosafety. Conclusion: A theranostic nanoplatform was successfully constructed, achieving PA imaging-guided SDT against breast cancer cells/tissue. More importantly, MNPs and HMME in one platform with combined effect for enhancing PA imaging was demonstrated. This unique theranostic nanoplatform with multiple capabilities paves a new way toward personalized medicine by rational utilization.

Nanobiotechnology medical applications: Overcoming challenges through innovation

Biomedical Nanotechnology (BNT) has rapidly become a revolutionary force that is driving innovation in the medical field. BNT is a subclass of nanotechnology (NT), and often operates in cohort with other subclasses, such as mechanical or electrical NT for the development of diagnostic assays, therapeutic implants, nano-scale imaging systems, and medical machinery. BNT is generating solutions to many conventional challenges through the development of enhanced therapeutic delivery systems, diagnostic techniques, and theranostic therapies. Therapeutically, BNT has generated many novel nanocarriers (NCs) that each express specifically designed physiochemical properties that optimize their desired pharmacokinetic profile. NCs are also being integrated into nanoscale platforms that further enhance their delivery by controlling and prolonging their release profile. Nano-platforms are also proving to be highly efficient in tissue regeneration when combined with the appropriate growth factors. Regarding diagnostics, NCs are being designed to perform targeted delivery of luminescent tags and contrast agents that enhance the NC -aided imaging capabilities and resulting diagnostic accuracy of the presence of diseased cells. This technology has also been advancing the ability for surgeons to practice true precision surgical techniques. Incorporating therapeutic and diagnostic NC-components within a single NC can facilitate both functions, referred to as theranostics, which facilitates real-time in vivo tracking and observation of drug release events via enhanced imaging. Additionally, stimuli-responsive theranostic NCs are quickly developing as vectors for tumor ablation therapies by providing a model that facilitates the location of cancer cells for the application of an external stimulus. Overall, BNT is an interdisciplinary approach towards health care, and has the potential to significantly improve the quality of life for humanity by significantly decreasing the treatment burden for patients, and by providing non-invasive therapeutics that confer enhanced therapeutic efficiency and safety

Hyperthermia induces therapeutic effectiveness and potentiates adjuvant therapy with non-targeted and targeted drugs in an in vitro model of human malignant melanoma

In the present study, we have aimed to characterize the intrinsic, extrinsic and ER-mediated apoptotic induction by hyperthermia in an in vitro model of human malignant melanoma and furthermore, to evaluate its therapeutic effectiveness in an adjuvant therapeutic setting characterized by combinational treatments with non-targeted (Dacarbazine & Temozolomide) and targeted (Dabrafenib & Vemurafenib) drugs. Overall, our data showed that both low (43 °C) and high (45 °C) hyperthermic exposures were capable of inducing cell death by activating all apoptotic pathways but in a rather distinct manner. More specifically, low hyperthermia induced extrinsic and intrinsic apoptotic pathways both of which activated caspase 6 only as opposed to high hyperthermia which was mediated by the combined effects of caspases 3, 7 and 6. Furthermore, significant involvement of the ER was evident (under both hyperthermic conditions) suggesting its role in regulating apoptosis via activation of CHOP. Our data revealed that while low hyperthermia activated IRE-1 and ATF6 only, high hyperthermia induced activation of PERK as well suggesting that ultimately these ER stress sensors can lead to the induction of CHOP via different pathways of transmitted signals. Finally, combinational treatment protocols revealed an effect of hyperthermia in potentiating the therapeutic effectiveness of non-targeted as well as targeted drugs utilized in the clinical setting. Overall, our findings support evidence into hyperthermia's therapeutic potential in treating human malignant melanoma by elucidating the underlying mechanisms of its complex apoptotic induction.