Gold over Branched Palladium Nanostructures for Photothermal Cancer Therapy

Programming Intracellular Clustering of Spiky Nanoparticles via Liposome Encapsulation

The intracellular clustering of anisotropic nanoparticles is crucial to the improvement of the localized surface plasmon resonance (LSPR) for phototherapy applications. Herein, we programmed the intracellular clustering process of spiky nanoparticles (SNPs) by encapsulating them into an anionic liposome via a frame-guided self-assembly approach. The liposome-encapsulated SNPs (lipo-SNPs) exhibited distinct and enhanced lysosome-triggered aggregation behavior while maintaining excellent monodispersity, even in acidic or protein-rich environments. We explored the enhancement of the photothermal therapy performance for SNPs as a proof of concept. The photothermal conversion efficiency of lipo-SNPs clusters significantly increased 15 times compared to that of single lipo-SNPs. Upon accumulation in lysosomes with a 2.4-fold increase in clustering, lipo-SNPs resulted in an increase in cell-killing efficiency to 45% from 12% at 24 μg/mL. These findings indicated that liposome encapsulation provides a promising approach to programing nanoparticle clustering at the target site, which facilitates advances in the development of smart nanomedicine with programmable enhancement in LSPR.

Multifunctional chitosan-bimetallic nanocarrier deliver 5-fluorouracil for enhanced treatment of pancreatic and triple-negative breast cancer

This work aimed to prepare multifunctional aptamer-conjugated, photothermally responsive 5-fluorouracil (5fu)-loaded chitosan-bimetallic (Au/Pd) nanoparticles (APT-CS-5fu-Au/Pd NPs) for improved cytotoxicity in two cancer cell lines (PANC-1 and MDA-MD 231). The CS-5fu-Au/Pd NPs were polydispersed with a size of 34.43 ± 1.59 nm. FTIR analysis indicated the presence of CS, 5fu in CS-5fu-Au/Pd NPs. The 2 theta degrees in CS-5fu-Au/Pd NPs accounted for CS and Au/Pd. Additionally, AGE revealed the conjugation of APT in CS-5fu-Au/Pd NPs. The APT-CS-5fu-Au/Pd NPs (180 μg/mL) with NIR treatment increased the temperature to >50 °C. The optimized 5fu input was 0.075 % in CS-5fu-Au/Pd NPs, exhibiting a hydrodynamic size of 112.96 ± 17.23 nm, DEE of 64.2 ± 3.77 %, and DLE of 11.1 ± 0.65 %. A higher level of 5fu release (69.8 ± 2.78 %) was observed under pH 5.4 at 74 h. In conclusion, NIR-APT-CS-5fu-Au/Pd NPs did not cause toxicity to RBC and Egg CAM, but increased cytotoxicity in MDA-MB 231 and PANC-1 cells by triggering oxidative stress-mediated cell death.

Indocyanine Green-Loaded Halloysite Nanotubes as Photothermal Agents

Photothermal nanoparticles with light-to-heat conversion properties have gained interest in recent years and have been used in a variety of applications. Herein, indocyanine green (ICG), which is commonly employed as a photothermal agent suffering from low photostability, was loaded into halloysite nanotubes (HNTs) resulting in photothermal HNT-ICG nanohybrids. The photothermal heating patterns of the prepared photothermal nanohybrids as a result of near-infrared (NIR) irradiation were carefully examined. The nanohybrids reached a temperature of 216 °C in 2 min under NIR light, and in contrast to free NIR, the ICG loaded into HNTs remained stable over 10 heating and cooling cycles. Moreover, HNT-ICG nanohybrids incorporated into polyacrylonitrile (PAN) were electrospun into nanofibers for use as photothermal nanofibers, and composite nanofibers, which heat up to 79.3 °C under 2 min of NIR irradiation, were obtained. To demonstrate the potential of the PAN/HNT-ICG nanofibers as light-activated antibacterial nanofibers, their NIR light-activated killing activity on Staphylococcus aureus (S. aureus) cells has been explored. The composite nanofibers reduced the number of bacteria on their surface by 7log upon 10 min of NIR irradiation. Encapsulation of ICG in HNTs as a carrier has been demonstrated as an effective way to stabilize ICG and incorporate it into materials and coatings without compromising its functionality.

Efficient and biocompatible new palladium-supported boehmite nanoparticles: synthesis, characterization and application in Suzuki-Miura and Mizoroki-Heck coupling reactions

Palladium complex-supported on boehmite (Pd(0)-SMTU-boehmite) nanoparticles were synthesized and characterized by using XRD, SEM, EDS, TGA, BET, ICP and FT-IR techniques. When applied as a new catalyst for C-C coupling reactions of Suzuki-Miyaura and Mizoroki-Heck in PEG-400 solvent, the Pd(0)-SMTU-boehmite nanoparticles showed excellent activity and recyclability. The study of palladium leaching by the ICP-OES technique and hot filtration led to the catalyst exhibiting excellent stability and recyclability.

Recent advances of nanocrystals in cancer theranostics

Emerging cancer cases across the globe and treating them with conventional therapies with multiple limitations have been challenging for decades. Novel drug delivery systems and alternative theranostics are required for efficient detection and treatment. Nanocrystals (NCs) have been established as a significant cancer diagnosis and therapeutic tool due to their ability to deliver poorly water-soluble drugs with sustained release, low toxicity, and flexibility in the route of administration, long-term sustainable drug release, and noncomplicated excretion. This review summarizes several therapies of NCs, including anticancer, immunotherapy, radiotherapy, biotheranostics, targeted therapy, photothermal, and photodynamic. Further, different imaging and diagnostics using NCs are mentioned, including imaging, diagnosis through magnetic resonance imaging (MRI), computed tomography (CT), biosensing, and luminescence. In addition, the limitations and potential solutions of NCs in the field of cancer theranostics are discussed. Preclinical and clinical data depicting the importance of NCs in the spotlight of cancer, its current status, future aspects, and challenges are covered in detail.

Nanodrugs systems for therapy and diagnosis of esophageal cancer

With the increasing incidence of esophageal cancer, its diagnosis and treatment have become one of the key issues in medical research today. However, the current diagnostic and treatment methods face many unresolved issues, such as low accuracy of early diagnosis, painful treatment process for patients, and high recurrence rate after recovery. Therefore, new methods for the diagnosis and treatment of esophageal cancer need to be further explored, and the rapid development of nanomaterials has brought new ideas for solving this problem. Nanomaterials used as drugs or drug delivery systems possess several advantages, such as high drug capacity, adjustably specific targeting capability, and stable structure, which endow nanomaterials great application potential in cancer therapy. However, even though the nanomaterials have been widely used in cancer therapy, there are still few reviews on their application in esophageal cancer, and systematical overview and analysis are deficient. Herein, we overviewed the application of nanodrug systems in therapy and diagnosis of esophageal cancer and summarized some representative case of their application in diagnosis, chemotherapy, targeted drug, radiotherapy, immunity, surgery and new therapeutic method of esophageal cancer. In addition, the nanomaterials used for therapy of esophageal cancer complications, esophageal stenosis or obstruction and oesophagitis, are also listed here. Finally, the challenge and the future of nanomaterials used in cancer therapy were discussed.

Surface-modified Ti3C2 MXene nanosheets for mesenchymal stem cell osteogenic differentiation via photothermal conversion

In the field of bone tissue engineering, the practical application of growth factors is limited by various factors such as systemic toxicity, instability, and the potential to induce inflammation. To circumvent these limitations, the use of physical signals, such as thermal stimulation, to regulate stem cells has been proposed as a promising alternative. The present study aims to investigate the potential of the two-dimensional nanomaterial Ti₃C₂ MXene, which exhibits unique photothermal properties, to induce osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) via photothermal conversion. Surface modification of Ti₃C₂ MXene nanosheets with PVP (Ti₃C₂-PVP) was employed to enhance their colloidal stability in physiological solutions. Characterization and cellular experiments showed that Ti₃C₂-PVP nanosheets have favorable photothermal properties and biocompatibility. Our study demonstrated that the induction of photothermal stimulation by co-culturing Ti₃C₂-PVP nanosheets with BMSCs and subsequent irradiation with 808 nm NIR significantly promoted cell proliferation, adhesion and osteogenic differentiation of BMSCs. In conclusion, the results of this study suggest that Ti₃C₂-PVP is a promising material for bone tissue engineering applications as it can modulate the cellular functions of BMSCs through photothermal conversion.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Single laser activated photothermal/photodynamic dual-modal cancer phototherapy by using ROS-responsive targeting flower-like ruthenium nanoparticles

Phototherapy, which mainly includes photothermal therapy (PTT) and photodynamic therapy (PDT), is one of the most promising strategies for cancer therapeutics. Ruthenium as a metal nanomaterial shows great potential as a phototherapy agent. Herein, we developed flower-like ruthenium nanoparticles (FRuNPs) to enhance cancer phototherapy. Compared with spherical ruthenium nanoparticles (SRuNPs) of a similar size, FRuNPs exhibited more enhanced near-infrared (NIR) absorption. FRuNPs exhibited a superior photothermal effect, which significantly improved the efficiency of PTT. Intracellular reactive oxide species (ROS) generation was recognized as the primary mechanism of PDT treatment. FRuNPs mediated the generation of ROS when exposed to 808 nm laser irradiation. Moreover, with the synergistic effect of PTT and PDT in FRuNPs, the phototherapeutic effects were obviously enhanced. In vitro phototherapy of MCF-7 cells in the presence of FRuNPs led to nearly 100% cell death under irradiation with an 808 nm laser. And in vivo FRuNPs further showed the capacity of in completely clearing the tumor tissues and improving the hypoxia environment with 14 days for interval laser irradiation. These results indicate that FRuNPs have versatile potential for tumor phototherapy.

Synthetic Strategies to Enhance the Electrocatalytic Properties of Branched Metal Nanoparticles

ConspectusBranched metal nanoparticles have unique catalytic properties because of their high surface area with multiple branches arranged in an open 3D structure that can interact with reacting species and tailorable branch surfaces that can maximize the exposure of desired catalytically active crystal facets. These exceptional properties have led to the exploration of the roles of branch structural features ranging from the number and dimensions of branches at the larger scales to the atomic-scale arrangement of atoms on precise crystal facets. The fundamental significance of how larger-scale branch structural features and atomic-scale surface faceting influence and control the catalytic properties has been at the forefront of the design of branched nanoparticles for catalysis. Current synthetic advances have enabled the formation of branched nanoparticles with an unprecedented degree of control over structural features down to the atomic scale, which have unlocked opportunities to make improved nanoparticle catalysts. These catalysts have high surface areas with controlled size and surface facets for achieving exceedingly high activity and stability. The synthetic advancement has recently led to the use of branched nanoparticles as ideal substrates that can be decorated with a second active metal in the form of islands and single atoms. These decorated branched nanoparticles have new and highly effective catalytic active sites where both branch metal and decorating metal play essential roles during catalysis.In the opening half of this Account, we critically assess the important structural features of branched nanoparticles that control catalytic properties. We first discuss the role of branch dimensions and the number of branches that can improve the surface area but can also trap gas bubbles. We then investigate the atomic-scale structural features of exposed surface facets, which are critical for enhancing catalytic activity and stability. Well-defined branched nanoparticles have led to a fundamental understanding of how the branch structural features influence the catalytic activity and stability, which we highlight for the oxygen evolution reaction (OER) and biomass oxidation. In discussing recent breakthroughs for branched nanoparticles, we explore the opportunities created by decorated branched nanoparticles and the unique bifunctional active sites that are exposed on the branched nanoparticle surfaces. This class of catalysts is of rapidly growing importance for reactions including the hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR), where two exposed metals are required for efficient catalysis. In the second half of this Account, we explore recent advances in the synthesis of branched nanoparticles and highlight the cubic-core hexagonal-branch growth mechanism that has achieved excellent control of all of the important structural features, including branch dimensions, number of branches, and surface facets. We discuss the slow precursor reduction as an effective strategy for decorating metal islands with controlled loadings on the branched nanoparticle surfaces and the spread of these metal islands to form single-atom active sites. We envisage that the key synthetic and structural advances identified in this Account will guide the development of the next-generation electrocatalysts.

Functionalized Nanostructured Bioactive Carriers: Nanoliposomes, Quantum Dots, Tocosome and Theranostic Approach

BACKGROUND

Lipidic nanocarriers have great potential for the encapsulation and delivery of numerous bioactive compounds. They have demonstrated significant benefits over traditional disease management and conventional therapy. The benefits associated with the particular properties of lipidic nanocarriers include site-specific drug deposition, improved pharmacokinetics and pharmacodynamics, enhanced internalization and intracellular transport, biodegradability, and decreased biodistribution. These properties result in the alleviation of the harmful consequences of conventional treatment protocols. Scope and approach: The administration of various bioactive molecules has been extensively investigated using nanostructured lipid carriers. In this article, theranostic applications of novel formulations of lipidic nanocarriers combined or complexed with quantum dots, certain polymers such as chitosan, and metallic nanoparticles (particularly gold) are reviewed. These formulations have demonstrated better controlled release features, improved drug loading capability, as well as a lower burst release rate. As a recent innovation in the field of drug delivery, tocosomes and their unique advantages are also explained in the final section of this entry.

KEY FINDINGS AND CONCLUSIONS

Theranostic medicine requires nanocarriers with improved target-specific accumulation and bio-distribution. Towards this end, lipid-based nanocarrier systems and tocosomes combined with unique properties of quantum dots, biocompatible polymers, and metallic nanoparticles seem to be ideal candidates to be considered for safe and efficient drug delivery.

Heterometallic nanomaterials: Activity modulation, sensing, imaging and therapy

Heterometallic nanomaterials (HMNMs) display superior physicochemical properties and stability to monometallic counterparts, accompanied by wider applications in the fields of catalysis, sensing, imaging, and therapy due to synergistic effects between multi-metals in HMNMs. So far, most reviews have mainly concentrated on introduction of their preparation approaches, morphology control and applications in catalysis, assay of heavy metal ions, and antimicrobial activity. Therefore, it is very important to summarize the latest investigations of activity modulation of HMNMs and their recent applications in sensing, imaging and therapy. Taking the above into consideration, we briefly underline appealing chemical/physical properties of HMNMs chiefly tailored through the sizes, shapes, compositions, structures and surface modification. Then, we particularly emphasize their widespread applications in sensing of targets (e.g. metal ions, small molecules, proteins, nucleic acids, and cancer cells), imaging (frequently involving photoluminescence, fluorescence, Raman, electrochemiluminescence, magnetic resonance, X-ray computed tomography, photoacoustic imaging, etc.), and therapy (e.g. radiotherapy, chemotherapy, photothermal therapy, photodynamic therapy, and chemodynamic therapy). Finally, we present an outlook on their forthcoming directions. This timely review would be of great significance for attracting researchers from different disciplines in developing novel HMNMs.

Heterometallic nanomaterials display wide applications in the fields of catalysis, sensing, imaging and therapy due to synergistic effects between the multi-metals.

Shape-Controllable Tellurium-Driven Heterostructures with Activated Robust Immunomodulatory Potential for Highly Efficient Radiophotothermal Therapy of Colon Cancer

Tellurium (Te)-based semiconductor easily leads to the recombination of photogenerated electron-hole pairs (h⁺-e^-) that severely limits the efficiency of reactive oxygen species (ROS) generation and further hinders its clinical application in biomedicine. With regard to these problems, herein we designed and synthesized a Te heterostructure (BTe-Pd-Au) by incorporating palladium (Pd) and gold (Au) elements to promote its radiosensitivity and photothermal performance, thus realizing highly efficient radiophotothermal tumor elimination by activating robust immunomodulatory potential. This shape-controllable heterostructure that coated by Pd on the surface of Te nanorods and Au in the center of Te nanorods was simply synthesized by using in situ synthesis method, which could promote the generation and separation of h⁺-e^- pairs, thereby exhibiting superior ROS producing ability and photothermal conversion efficiency. Using a mouse model of colon cancer, we proved that BTe-Pd-Au-R-combined radiophotothermal therapy not only eradicated tumor but also elicited to a series of antitumor immune responses by enhancing the cytotoxic T lymphocytes, triggering dendritic cells maturation, and decreasing the percentage of M2 tumor-associated macrophages. In summary, our study highlights a facile strategy to design Te-driven heterostructure with versatile performance in radiosensitization, photothermal therapy, and immunomodulation and offers great promise for clinical translational treatment of colon cancer.

Strong Penetration-Induced Effective Photothermal Therapy by Exosome-Mediated Black Phosphorus Quantum Dots

Nanocancer medicine, such as photothermal therapy (PTT), as a promising way to solve cancer without side effects, faces a huge biological barrier during the circulation of nanoparticles in the body, including nanobiological interactions in the blood, isolation of nanoparticles in the macrophage system, tumor spillover effect, and especially uneven intratumoral distribution of nanoparticles, which cast a shadow over the hope. To address the problem of intratumoral distribution, an effective photothermal agent is introduced by packaging the black phosphorus quantum dots (BPQDs) into exosome vector (EXO) through electroporation method. With the improving and proper stability for better therapy, the resulting BPQDs@EXO nanospheres (BEs) exhibit good biocompatibility, long circulation time, and excellent tumor targeting ability, hence impressive PTT efficiency evidenced by highly efficient tumor ablation in vivo. Importantly, great permeability on organoids contributed by EXO appears with BEs, which strongly promotes the efficient killing ability. These BP-based nanospheres must promise high clinical potential due to the high PTT efficiency and minimal side effects.

Transdermal delivery of multifunctional CaO2@Mn-PDA nanoformulations by microneedles for NIR-induced synergistic therapy against skin melanoma

The development of multifunctional nanoformulations (NFs) include several features in a single nanosystem for these devices to overcome the disadvantages of inefficiency and undesirable toxicity of traditional therapies and provide new opportunities in the management of tumors. Herein, multifunctional CaO₂@Mn-PDA NFs with a core-shell structure, integrating the photothermal conversion properties of Mn-PDA, the chemodynamic properties of doped Mn ions, and relieving hypoxia in the tumor microenvironment (TME) were developed. The as-fabricated CaO₂@Mn-PDA NFs were embedded in microneedles (MNs) for transdermal delivery into tumor sites, leading to the generation of a new minimally invasive and synergistic therapeutic strategy against skin melanoma. Under near-infrared (NIR) light irradiation, the CaO₂@Mn-PDA NFs exhibited a synergistic therapeutic effect, including photothermal therapy (PTT), chemodynamic therapy (CDT), and modulating hypoxia due to their high photothermal conversion efficiency, boosted intracellular production of reactive oxygen species, excellent chemodynamic reactions, etc. Therefore, the developed MN platform, which can build implanted multifunctional characteristics for on-demand NIR-induced synergistic therapy, have a bright future in tumor suppression.

Advances in photothermal nanomaterials for biomedical, environmental and energy applications

Materials that exhibit photothermal effect have attracted enormous research interests due to their ability to strongly absorb light and effectively transform it into heat for a wide range of applications in biomedical, environmental and energy related fields. The past decade has witnessed significant advances in the preparation of a variety of photothermal materials, mainly due to the emergence of many nano-enabled new materials, such as plasmonic metals, stoichiometric/non-stoichiometric semiconductors, and the newly emerging MXenes. These photothermal nanomaterials can be hybridized with other constituents to form functional hybrids or composites for achieving enhanced photothermal performance. In this review, we present the fundamental insight of inorganic photothermal materials, including their photothermal conversion mechanisms/properties as well as their potential applications in various fields. Emphasis is placed on strategic approaches for improving their light harvesting and photothermal conversion capabilities through engineering their nanostructured size, shape, composition, bandgap and so on. Lastly, the underlying challenges and perspectives for future development of photothermal nanomaterials are proposed.

Bimetallic Au@Pd nanodendrite system incorporating multimodal intracellular imaging for improved doxorubicin antitumor efficiency

The sufficient accumulation of drugs is crucial for efficient treatment in a complex tumor microenvironment. Drug delivery systems (DDS) with high surface area and selective cytotoxicity present a novel approach to mitigate insufficient drug loading for improved therapeutic response. Herein, a doxorubicin-conjugated bimetallic gold-core palladium-shell nanocarrier with multiple dense arrays of branches (Au@PdNDs.PEG/DOX) was characterized and its efficacy against breast adenocarcinoma (MCF-7) and lung adenocarcinoma (A549) cells were evaluated. Enhanced darkfield and hyperspectral imaging (HSI) microscopy were used to study the intracellular uptake and accumulation of the DOX-loaded nanodendrites A fascinating data from a 3D-CytoViva fluorescence imaging technique provided information about the dynamics of localization and distribution of the nanocarrier. In vitro cytotoxicity assays indicated that Au@PdNDs.PEG/DOX inhibited the proliferative effects of MCF-7 cells at equivalent IC₅₀ dosage compared to DOX alone. The nanocarrier triggered higher induction of apoptosis proved by a time-dependent phosphatidylserine V release, cell cycle arrest, and flow cytometry analysis. Moreover, the cell cycle phase proportion increase suggests that the enhanced apoptotic effect induced by Au@PdNDs.PEG/DOX was via a G2/M phase arrest. Thus, this study demonstrated the potential of dendritic nanoparticles to improve DOX therapeutic efficiency and plasmonic-mediated intracellular imaging as a suitable theranostic platform for deployment in nanomedicine.

Palladium Nanoparticle-Induced Oxidative Stress, Endoplasmic Reticulum Stress, Apoptosis, and Immunomodulation Enhance the Biogenesis and Release of Exosome in Human Leukemia Monocytic Cells (THP-1)

Background

Exosomes are endosome-derived nano-sized vesicles that have emerged as important mediators of intercellular communication and play significant roles in various diseases. However, their applications are rigorously restricted by the limited secretion competence of cells. Therefore, strategies to enhance the production and functions of exosomes are warranted. Studies have shown that nanomaterials can significantly enhance the effects of cells and exosomes in intercellular communication; however, how palladium nanoparticles (PdNPs) enhance exosome release in human leukemia monocytic cells (THP-1) remains unclear. Therefore, this study aimed to address the effect of PdNPs on exosome biogenesis and release in THP-1 cells.

Methods

Exosomes were isolated by ultracentrifugation and ExoQuick^TM and characterized by dynamic light scattering, nanoparticle tracking analysis system, scanning electron microscopy, transmission electron microscopy, EXOCET^TM assay, and fluorescence polarization. The expression levels of exosome markers were analyzed via quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay.

Results

PdNP treatment enhanced the biogenesis and release of exosomes by inducing oxidative stress, endoplasmic reticulum stress, apoptosis, and immunomodulation. The exosomes were spherical in shape and had an average diameter of 50–80 nm. Exosome production was confirmed via total protein concentration, exosome counts, acetylcholinesterase activity, and neutral sphingomyelinase activity. The expression levels of TSG101, CD9, CD63, and CD81 were significantly higher in PdNP-treated cells than in control cells. Further, cytokine and chemokine levels were significantly higher in exosomes isolated from PdNP-treated THP-1 cells than in those isolated from control cells. THP-1 cells pre-treated with N-acetylcysteine or GW4869 showed significant decreases in PdNP-induced exosome biogenesis and release.

Conclusion

To our knowledge, this is the first study showing that PdNPs stimulate exosome biogenesis and release and simultaneously increase the levels of cytokines and chemokines by modulating various physiological processes. Our findings suggest a reasonable approach to improve the production of exosomes for various therapeutic applications.

Controllable Synthesis of Bimetallic Nanostructures Using Biogenic Reagents: A Green Perspective

Bimetallic nanostructures are emerging as a significant class of metal nanomaterials due to their exceptional properties that are useful in various areas of science and technology. When used for catalysis and sensing applications, bimetallic nanostructures have been noted to exhibit better performance relative to their monometallic counterparts owing to synergistic effects. Furthermore, their dual metal composition and configuration can be modulated to achieve optimal activity for the desired functions. However, as with other nanostructured metals, bimetallic nanostructures are usually prepared through wet chemical routes that involve the use of harsh reducing agents and hazardous stabilizing agents. In response to intensifying concerns over the toxicity of chemicals used in nanomaterial synthesis, the scientific community has increasingly turned its attention toward environmentally and biologically compatible reagents that can enable green and sustainable nanofabrication processes. This article aims to provide an evaluation of the green synthetic methods of constructing bimetallic nanostructures, with emphasis on the use of biogenic resources (e.g., plant extracts, DNA, proteins) as safe and practical reagents. Special attention is devoted to biogenic synthetic protocols that demonstrate controllable nanoscale features, such as size, composition, morphology, and configuration. The potential use of these biogenically prepared bimetallic nanostructures as catalysts and sensors is also discussed. It is hoped that this article will serve as a valuable reference on bimetallic nanostructures and will help fuel new ideas for the development of more eco-friendly strategies for the controllable synthesis of various types of nanostructured bimetallic systems.

M. M. de Almeida J, Pastoriza-Santos I, C. C. Coelho L. Advances in Plasmonic Sensing at the NIR-A Review

Surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR) are among the most common and powerful label-free refractive index-based biosensing techniques available nowadays. Focusing on LSPR sensors, their performance is highly dependent on the size, shape, and nature of the nanomaterial employed. Indeed, the tailoring of those parameters allows the development of LSPR sensors with a tunable wavelength range between the ultra-violet (UV) and near infra-red (NIR). Furthermore, dealing with LSPR along optical fiber technology, with their low attenuation coefficients at NIR, allow for the possibility to create ultra-sensitive and long-range sensing networks to be deployed in a variety of both biological and chemical sensors. This work provides a detailed review of the key science underpinning such systems as well as recent progress in the development of several LSPR-based biosensors in the NIR wavelengths, including an overview of the LSPR phenomena along recent developments in the field of nanomaterials and nanostructure development towards NIR sensing. The review ends with a consideration of key advances in terms of nanostructure characteristics for LSPR sensing and prospects for future research and advances in this field.

Noble Metal Nanomaterials for NIR-Triggered Photothermal Therapy in Cancer

It is of great significance to develop anticancer therapeutic agents or technologies with high degree of specificity and patient compliance, while low toxicity. The emerging photothermal therapy (PTT) has become a new and powerful therapeutic technology due to its noninvasiveness, high specificity, low side effects to normal tissues and strong anticancer efficacy. Noble metal nanomaterials possess strong surface plasmon resonance (SPR) effect and synthetic tunability, which make them facile and effective PTT agents with superior optical and photothermal characteristics, such as high absorption cross-section, incomparable optical-thermal conversion efficiency in the near infrared (NIR) region, as well as the potential of bioimaging. By incorporating with various functional reagents such as antibodies, peptides, biocompatible polymers, chemo-drug and immune factors, noble metal nanomaterials have presented strong potential in multifunctional cancer therapy. Herein, the recent development regarding the application of noble metal nanomaterials for NIR-triggered PTT in cancer treatment is summarized. A variety of studies with good therapeutic effects against cancer from impressive photothermal efficacy of noble metal nanomaterials are concluded. Intelligent nanoplatforms through ingenious fabrication showing potential of multifunctional PTT, combined with chemo-therapy, immunotherapy, photodynamic therapy (PDT), as well as simultaneous imaging modality are also demonstrated.

Laser-induced optothermal response of gold nanoparticles: From a physical viewpoint to cancer treatment application

Gold nanoparticles (GNPs)-based photothermal therapy (PTT) is a promising minimally invasive thermal therapy for the treatment of focal malignancies. Although GNPs-based PTT has been known for over two decades and GNPs possess unique properties as therapeutic agents, the delivery of a safe and effective therapy is still an open question. This review aims at providing relevant and recent information on the usage of GNPs in combination with the laser to treat cancers, pointing out the practical aspects that bear on the therapy outcome. Emphasis is given to the assessment of the GNPs' properties and the physical mechanisms underlying the laser-induced heat generation in GNPs-loaded tissues. The main techniques available for temperature measurement and the current theoretical simulation approaches predicting the therapeutic outcome are reviewed. Topical challenges in delivering safe thermal dosage are also presented with the aim to discuss the state-of-the-art and the future perspective in the field of GNPs-mediated PTT.

Enriching the branching of Au@PdAu core–shell nanocrystals using a syringe pump: kinetics control meets lattice mismatch

Gold@palladium–gold nanocrystals with a tunable branched shape are prepared via seeded growth, where the use of a syringe pump allows the manipulation over reaction kinetics as coupled by surface diffusion and strain caused by lattice mismatch.

Tumor size-dependent abscopal effect of polydopamine-coated all-in-one nanoparticles for immunochemo-photothermal therapy of early- and late-stage metastatic cancer

Metastatic cancer is a persistent clinical enigma, which requires combination of several treatment modules. Here, we developed an all-in-one nanomedicine strategy to systemically co-deliver photosensitive, chemotherapeutic, and immunomodulating agents for effective immunochemo-photothermal therapy (PTT) to inhibit both primary tumor and distal metastatic tumor. Two types of polydopamine (dp)-coated nanoparticles (NPs) (N/PGEM/dp-5 and N/PGEM/dp-16) co-loaded with gemcitabine (GEM) and NLG919, a potent indoleamine-2, 3-dioxygenase (IDO) inhibitor, were prepared. N/PGEM/dp-16 NPs with a thicker dp coating layer showed higher photothermal conversion ability, more favorable biodistribution profile and better tumor inhibition effect compared to N/PGEM/dp-5 NPs with a thinner coating layer. Combination with laser irradiation further enhanced the tumor inhibition effect of N/PGEM/dp-16 NPs. In an "early metastatic" pancreatic cancer PANC02 model with small distal tumors, introduction of NLG and dp coating improved the inhibition effect on both primary and distal tumors. Compared to N/PGEM/dp-16, N/PGEM/dp-16 plus laser irradiation further enhanced the inhibition effect on primary tumor, but didn't improve the abscopal antitumor effect. When the initial volume of distal tumor was sufficiently large in a "late metastasis" model, a more dramatic abscopal antitumor effect was achieved, resulting in a significant growth inhibition of both primary tumor and the unirradiated distal tumor. Furthermore, laser irradiation can amplify the immunochemo-NPs-mediated innate and adaptive immune responses in both tumors. This work demonstrated a distal tumor-size dependent abscopal effect, and provided a perspective for future design of more effective immunochemo-PTT nano-formulations for early- and late-stage metastatic tumors.

Progress of Cancer Nanotechnology as Diagnostics, Therapeutics, and Theranostics Nanomedicine: Preclinical Promise and Translational Challenges

Early detection, right therapeutic intervention, and simultaneous effectiveness mapping are considered the critical factors in successful cancer therapy. Nevertheless, these factors experience the limitations of conventional cancer diagnostics and therapeutics delivery approaches. Along with providing the targeted therapeutics delivery, advances in nanomedicines have allowed the combination of therapy and diagnostics in a single system (called cancer theranostics). This paper discusses the progress in the pre-clinical and clinical development of therapeutics, diagnostics, and theranostics cancer nanomedicines. It has been well evident that compared to the overabundance of works that claimed success in pre-clinical studies, merely 15 and around 75 cancer nanomedicines are approved, and currently under clinical trials, respectively. Thus, we also brief the critical bottlenecks in the successful clinical translation of cancer nanomedicines.

Light: A Magical Tool for Controlled Drug Delivery

Light is a particularly appealing tool for on-demand drug delivery due to its noninvasive nature, ease of application and exquisite temporal and spatial control. Great progress has been achieved in the development of novel light-driven drug delivery strategies with both breadth and depth. Light-controlled drug delivery platforms can be generally categorized into three groups: photochemical, photothermal, and photoisomerization-mediated therapies. Various advanced materials, such as metal nanoparticles, metal sulfides and oxides, metal-organic frameworks, carbon nanomaterials, upconversion nanoparticles, semiconductor nanoparticles, stimuli-responsive micelles, polymer- and liposome-based nanoparticles have been applied for light-stimulated drug delivery. In view of the increasing interest in on-demand targeted drug delivery, we review the development of light-responsive systems with a focus on recent advances, key limitations, and future directions.

Therapeutic nanodendrites: current applications and prospects

Multidisciplinary efforts in the field of nanomedicine for cancer therapy to provide solutions to common limitations of traditional drug administration such as poor bioaccumulation, hydrophobicity, and nonspecific biodistribution and targeting have registered very promising progress thus far. Currently, a new class of metal nanostructures possessing a unique dendritic-shaped morphology has been designed for improved therapeutic efficiency. Branched metal nanoparticles or metal nanodendrites are credited to present promising characteristics for biomedical applications owing to their unique physicochemical, optical, and electronic properties. Nanodendrites can enhance the loading efficiency of bioactive molecules due to their three-dimensional (3D) high surface area and can selectively deliver their cargo to tumor cells using their stimuli-responsive properties. With the ability to accumulate sufficiently within cells, nanodendrites can overcome the detection and clearance by glycoproteins. Moreover, active targeting ligands such as antibodies and proteins can as well be attached to these therapeutic nanodendrites to enhance specific tumor targeting, thereby presenting a multifunctional nanoplatform with tunable strategies. This mini-review focuses on recent developments in the understanding of metallic nanodendrite synthesis, formation mechanism, and their therapeutic capabilities for next-generation cancer therapy. Finally, the challenges and future opportunities of these fascinating materials to facilitate extensive research endeavors towards the design and application were discussed.

2D AuPd alloy nanosheets: one-step synthesis as imaging-guided photonic nano-antibiotics

The complicated synthesis and undesirable biocompatibility of nanomaterials hinder the synergistic photothermal/photodynamic therapy for bacterial infections. Herein, we develop a one-step preparation method of 2D AuPd alloy nanosheets as imaging-guided photonic nano-antibiotics. 2D AuPd alloy nanosheets with an extremely small thickness (∼1.5 nm) exhibit prominent photothermal effects (η = 76.6%), excellent ROS generation, strong photoacoustic signals and desirable biocompatibility. AuPd nanosheets can eliminate 100% of representative Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) when irradiated using an 808 nm laser at 1 W cm^-2 for 5 minutes. After being modified with a bacterial targeting peptide, under the guidance of photoacoustic imaging, AuPd nanosheets achieve promising synergistic photothermal/photodynamic therapeutic efficacy in treating Staphylococcus aureus infected mice. This work expands the biomedical application of 2D noble metal nanomaterials to the field of photonic nano-antibiotics.

Persistent luminescence-polypyrrole nanocomposite for dual-modal imaging and photothermal therapy of mammary cancer

Multifunctional nanocomposites that possess imaging and high-performance therapeutic features are experiencing a surge in interest in the precision clinical anticancer treatment. In this work, we reported the fabrication and bio-application of a novel persistent luminescence-polypyrrole nanocomposite (LPLNP@SPP) for photoacoustic/persistent luminescence (PA/PL) dual-modal imaging guided photothermal therapy (PTT). The construction of LPLNP@SPP avoids the PL quenching of LPLNP-OH by the polypyrrole-coating, and thus enables the combination of PL and PTT. The LPLNP@SPP shows excellent biocompatibility, long lasting near-infrared (NIR) PL emitting without in situ excitation and high-contrast PA signals. Meanwhile, this nanocomposite exhibits strong NIR absorbance and exceptional photothermal conversion capability, which provides notable potential for imaging-guided antitumor therapy. Thus, our work highlights the dual-functional core-shell LPLNP@SPP as a feasible theranostic nanoplatform for cancer diagnosis and therapy.

Nanoparticles-encapsulated polymeric microneedles for transdermal drug delivery

Polymeric microneedles (MNs) have been leveraged as a novel transdermal drug delivery platform for effective drug permeation, which were widely used in the treatment of various diseases. However, issues including limited loading capacity of hydrophobic drugs, uncontrollable drug release rates, and monotonic therapeutic strategy hamper the further application of polymeric MNs. As a recent emerging research topic, drawing inspiration from the ways that nanomedicine integrated with MNs have opened new avenues for disease therapy. In this review, we examined the recent studies employing nanoparticles (NPs)-encapsulated polymeric MNs (NPs@MNs) for transdermal delivery of various therapeutic cargos, particularly focused on the application of NPs@MNs for diabetes therapy, infectious disease therapy, cancer therapy, and other dermatological disease therapy. We also provided an overview of the clinical potential and future translation of NPs@MNs.

Melatonin Enhances Palladium-Nanoparticle-Induced Cytotoxicity and Apoptosis in Human Lung Epithelial Adenocarcinoma Cells A549 and H1229

Palladium nanoparticles (PdNPs) are increasingly being used in medical and biological applications due to their unique physical and chemical properties. Recent evidence suggests that these nanoparticles can act as both a pro-oxidant and as an antioxidant. Melatonin (MLT), which also shows pro- and antioxidant properties, can enhance the efficacy of chemotherapeutic agents when combined with anticancer drugs. Nevertheless, studies regarding the molecular mechanisms underlying the anticancer effects of PdNPs and MLT in cancer cells are still lacking. Therefore, we aimed to investigate the potential toxicological and molecular mechanisms of PdNPs, MLT, and the combination of PdNPs with MLT in A549 lung epithelial adenocarcinoma cells. We evaluated cell viability, cell proliferation, cytotoxicity, oxidative stress, mitochondrial dysfunction, and apoptosis in cells treated with different concentrations of PdNPs and MLT. PdNPs and MLT induced cytotoxicity, which was confirmed by leakage of lactate dehydrogenase, increased intracellular protease, and reduced membrane integrity. Oxidative stress increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), nitric oxide (NO), protein carbonyl content (PCC), lipid hydroperoxide (LHP), and 8-isoprostane. Combining PdNPs with MLT elevated the levels of mitochondrial dysfunction by decreasing mitochondrial membrane potential (MMP), ATP content, mitochondrial number, and expression levels of the main regulators of mitochondrial biogenesis. Additionally, PdNPs and MLT induced apoptosis and oxidative DNA damage due to accumulation of 4-hydroxynonenal (HNE), 8-oxo-2'-deoxyguanosine (8-OhdG), and 8-hydroxyguanosine (8-OHG). Finally, PdNPs and MLT increased mitochondrially mediated stress and apoptosis, which was confirmed by the increased expression levels of apoptotic genes. To our knowledge, this is the first study demonstrating the effects of combining PdNPs and MLT in human lung cancer cells. These findings provide valuable insights into the molecular mechanisms involved in PdNP- and MLT-induced toxicity, and it may be that this combination therapy could be a potential effective therapeutic approach. This combination effect provides information to support the clinical evaluation of PdNPs and MLT as a suitable agents for lung cancer treatment, and the combined effect provides therapeutic value, as non-toxic concentrations of PdNPs and MLT are more effective, better tolerated, and show less adverse effects. Finally, this study suggests that MLT could be used as a supplement in nano-mediated combination therapies used to treat lung cancer.

Pd@Au Bimetallic Nanoplates Decorated Mesoporous MnO2 for Synergistic Nucleus-Targeted NIR-II Photothermal and Hypoxia-Relieved Photodynamic Therapy

Bimetallic nanoparticles have received considerable attention owing to synergistic effect and their multifunctionality. Herein, new multifunctional Pd@Au bimetallic nanoplates decorated hollow mesoporous MnO₂ nanoplates (H-MnO₂ ) are demonstrated for achieving not only nucleus-targeted NIR-II photothermal therapy (PTT), but also tumor microenvironment (TME) hypoxia relief enhanced photodynamic therapy (PDT). The Pd@Au nanoplates present a photothermal conversion efficiency (PTCE) as high as 56.9%, superior to those PTAs activated in the NIR-II region such as Cu₉ S₅ nanoparticles (37%), Cu₃ BiS₃ nanorods (40.7%), and Au/Cu_{2- x} S nanocrystals (43.2%). They further functionalize with transactivator of transcription (TAT) moiety for cell nuclear-targeting and biodegradable hollow mesoporous MnO₂ (≈100 nm) loaded with photosensitizer Ce6 (TAT-Pd@Au/Ce6/PAH/H-MnO₂ ) to construct a hierarchical targeting nanoplatform. The as-made TAT-Pd@Au/Ce6/PAH/H-MnO₂ demonstrates good premature renal clearance escape ability and increased tumor tissue accumulation. It can be degraded in acidic TME and generate O₂ by reacting to endogenous H₂ O₂ to relieve the hypoxia for enhanced PDT, while the released small TAT-Pd@Au nanoplates can effectively enter into the nucleus to mediate PTT. As a result, a remarkable therapeutic effect is achieved owing to the synergistic PTT/PDT therapy. This hierarchical targeting, TME-responsive, cytoplasm hypoxia relief PDT, and nuclear NIR-II PTT synergistic therapy can pave a new avenue for nanomaterials-based cancer therapy.

Bimetallic nanodots for tri-modal CT/MRI/PA imaging and hypoxia-resistant thermoradiotherapy in the NIR-II biological windows

Hypoxic tumor microenvironment leads to resistance or failure of radiotherapy (RT). As a non-invasive therapy, photothermal therapy (PTT) can improve the tumor hypoxic microenvironment in addition to directly killing tumor cells. PTT combined with RT (thermoradiotherapy) becomes an emerging treatment. Multi-functional nanoparticles used for hypoxia-resistant thermoradiotherapy in the second near-infrared (NIR-II) biological windows (1000-1700 nm) are urgently needed to be developed. Here, a facil method synthesis of ultra-small cysteamine (Cys)-coated FePd bimetallic nanodots (NDs) is reported. These NDs can not only produce effective hyperthermia (35.4%) when irradiated in the NIR-II region (1064 nm) but also have an enhanced radiation effect due to i) Hypoxic improvement in tumor tissues by photothermal treatment in the NIR-II Biological Windows can greatly enhance the sensitivity of tumor cells to radiotherapy ii) The ability of NDs to deposit radiation energy in tumors has further enhanced the sensitivity of tumor cells to radiotherapy. Meanwhile, NDs was a contrast agent for tri-modal imaging including computed tomography (CT)/magnetic resonance imaging (MRI)/photoacoustic imaging (PAI) in vitro and in vivo. Both in vitro and in vivo tests demonstrated good biocompatibility and excellent stability of NDs, indicating great potential for clinical applications.

Advances in the Application of Magnetic Nanoparticles for Sensing

Magnetic nanoparticles (MNPs) are of high significance in sensing as they provide viable solutions to the enduring challenges related to lower detection limits and nonspecific effects. The rapid expansion in the applications of MNPs creates a need to overview the current state of the field of MNPs for sensing applications. In this review, the trends and concepts in the literature are critically appraised in terms of the opportunities and limitations of MNPs used for the most advanced sensing applications. The latest progress in MNP sensor technologies is overviewed with a focus on MNP structures and properties, as well as the strategies of incorporating these MNPs into devices. By looking at recent synthetic advancements, and the key challenges that face nanoparticle-based sensors, this review aims to outline how to design, synthesize, and use MNPs to make the most effective and sensitive sensors.

Near-Infrared Light-Triggered Porous AuPd Alloy Nanoparticles To Produce Mild Localized Heat To Accelerate Bone Regeneration

The treatment of massive bone defects is still a significant challenge for orthopedists. Here we have engineered synthetic porous AuPd alloy nanoparticles (pAuPds) as a hyperthermia agent for in situ bone regeneration through photothermal therapy (PTT). After being swallowed by cells, pAuPds produced a mild localized heat (MLH) (40-43 °C) under the irradiation of a near-infrared laser, which can greatly accelerate cell proliferation and bone regeneration. Almost 97% of the cranial defect area (8 mm in diameter) was covered by the newly formed bone after 6 weeks of PTT. RNA sequencing analysis was used to obtain insight into the molecular mechanism of the MLH on cell proliferation and bone formation. These results demonstrated that the Wnt signaling pathway was involved in the MLH. This Letter provides a unique strategy with mild heat stimulation and high efficiency for in situ bone regeneration.

Selective Separation of Pd(II) on Pyridine-Functionalized Graphene Oxide Prepared by Radiation-Induced Simultaneous Grafting Polymerization and Reduction

The recovery of precious metals like palladium (Pd) from secondary resources has enormous economic benefits and is in favor of resource reuse. In this work, we prepared a high efficiency pyridine-functionalized reduced graphene oxide (rGO) adsorbent for selective separation of Pd(II) from simulated electronic waste leachate, by one-pot γ-ray radiation-induced simultaneous grafting polymerization (RIGP) of 4-vinylpyridine (4VP) from graphene oxide (GO) and reduction of GO. The poly(4-vinylpyridine)-grafted reduced graphene oxide (rGO-g-P4VP) exhibits fast adsorption kinetics and high maximum adsorption capacity. The adsorption capacity is 105 mg g^-1 in the first minute and reaches equilibrium within 120 min. The adsorption process follows the Langmuir model, from which the maximum adsorption capacity of Pd(II) is estimated to be 177 mg g^-1. We also proved that the adsorption mechanism of Pd(II) on rGO-g-P4VP involves both ion exchange and coordination adsorption by XPS analysis. Most importantly, the loss of oxygen-containing groups due to reduction of GO not only facilitates the separation of adsorbent from aqueous solution but also reduces the electrostatic repulsion toward Pd(II)Cl₄^2- in hydrochloric acid solution, leading to a higher adsorption selectivity of Pd(II) over some common metal cations in electronic waste including Fe(III), Cu(II), and Al(III) compared with poly(4-vinylpyridine)-grafted graphene oxide (GO-g-P4VP) prepared by atom transfer radical polymerization. Other precious metals like Pt(IV) and Au(III) can also be recovered easily and selectively by rGO-g-P4VP. This work demonstrates that rGO-g-P4VP prepared by the facile RIGP is a promising adsorbent for recovery of precious metals from secondary resources like electronic waste leachate.

Hypoxia-Irrelevant Photonic Thermodynamic Cancer Nanomedicine

The hypoxic tumor microenvironment severely lowers the therapeutic efficacy of oxygen-dependent anticancer modalities because tumor hypoxia hinders the generation of toxic reactive oxygen species. Here we report a thermodynamic cancer-therapeutic modality that employs oxygen-irrelevant free radicals generated from thermo-labile initiators for inducing cancer cell death. A free radical nanogenerator was engineered via direct growth of mesoporous silica layer onto the surface of two-dimensional Nb₂C MXene nanosheets toward multifunctionality, where the mesopore provided the reservoirs for initiators and the MXene core acted as the photonic-thermal trigger at the near-infrared-II biowindow (NIR-II). Upon illumination by a 1064 nm NIR-II laser, the photothermal-conversion effect of Nb₂C MXene induced the fast release and quick decomposition of the encapsulated initiators (AIPH) to produce free radicals, which promoted cancer cell apoptosis in both normoxic and hypoxic microenvironment. Systematic in vitro and in vivo evaluations have demonstrated the synergistic-therapeutic outcome of this intriguing photonic nanoplatform-enabled thermodynamic cancer therapy for completely eradicating the 4T1 tumors without recurrence by NIR-II laser irradiation. This work pioneers the thermodynamic therapy for oxygen-independent cancer treatment by photonic triggering at the NIR-II biowindow.

Facet-regulated adhesion of double-stranded DNA on palladium surfaces

A better understanding of interactions between metal-nanomaterial surfaces and biomolecules such as DNAs is critical for their biomedical applications. Here we investigated double-stranded DNA (dsDNA) adhering to palladium (Pd) nanosheets with two different exposed facets, {100} and {111}, using a combined computational and experimental approach. Different dsDNA binding modes on the two surfaces were observed, with a surprising "upright" conformation on Pd(100) and a "flat" conformation on Pd(111). Molecular dynamics simulations showed a stronger binding of the dsDNA on Pd(111) than Pd(100), which resulted in significant conformational changes and hydrogen bond breakage in the dsDNA on Pd(111). Further analyses revealed that the different binding strengths were caused by the number and arrangement of water molecules in the first solvation shell (FSS) of the two Pd surfaces. The water hydrogen bond network in the FSS of Pd(100) is compact and resists the embedding of dsDNA, while it is less compact on Pd(111), which allows penetration of dsDNA and its direct contact with Pd(111) surface atoms, thereby exhibiting stronger binding. Further free energy calculations with umbrella sampling supported these observations. Finally, these computational predictions on the adsorption capacity of dsDNA on Pd surfaces were confirmed by gel electrophoresis experiments.

Transferrin-conjugated pH-sensitive platform for effective delivery of porous palladium nanoparticles and paclitaxel in cancer treatment

Porous palladium (Pd) nanoparticles have garnered great research attention due to their potential anticancer activity and photothermal effect. In this study, a transferrin-conjugated pH-sensitive platform (Tf-PPP), comprising porous Pd nanoparticles (PdNPs) and paclitaxel (PTX), was successfully developed for combined chemo-phototherapy. Tf-PPPs have a small size of 164.6 ± 8.7 nm, PDI of 0.278 ± 0.029, and negative charge (-13.2 ± 1.8 mV). Poly(acrylic acid)-poly(ethylene oxide) (PAA-PEO), a pH sensitive polymer, was used to achieve pH-dependent drug release from nanoparticles. Transferrin (Tf) conjugated on the surface of nanoplatforms could enhance the cellular uptake and prolong nanoparticle accumulation in the tumor site. The combination of phototherapy induced by PdNPs and chemotherapeutic agent (PTX) could exhibit synergistic anticancer activities. Consistent findings were observed in both in vitro experiments including cytotoxicity, live/dead assay, and assessment of apoptotic protein levels, and in vivo antitumor study in MCF-7 tumor-bearing mice, with results decreasing in the following order: Tf-PPPs + NIR > Tf-PPPs > PPPs + NIR > PPPs > PTX > PdNPs. These findings suggest that the administration of Tf-PPPs, followed by NIR irradiation could be a promising strategy in the treatment of cancer.

Flower-like gold nanoparticles for enhanced photothermal anticancer therapy by the delivery of pooled siRNA to inhibit heat shock stress response

Surface modified gold nanoflowers were employed as synergistic therapeutics for photothermal ablation and gene silencing.

Photothermal effect of Ag nanoparticles deposited over poly(amidoamine) grafted carbon nanotubes

This paper illustrates the potential of Ag nanoparticles based nanocomposites to use as effective agents in photothermal therapy apart from their traditional employment as antimicrobial materials. Herein an Near- Infrared active photothermal agent was fabricated by deposition of Ag nanoparticles over aromatic poly(amidoamine) grafted carbon nanotubes. Thus prepared CNTs-PAMAM-Ag possessed strong photothermal effect under exposure to 980 nm laser system and prominent photothermal stability. The photothermal conversion efficiency of CNTs-PAMAM-Ag was found to be higher than readily used Au and CuS based photothermal agents. The photothermal effect of CNTs-PAMAM-Ag was substantial in presence of 980 nm laser compared to 808 nm laser and a linear dependence of photothermal effect on its concentration was identified. The maximum temperature attained by CNTs-PAMAM-Ag during assessment of its photothermal effect was about 66.0 °C, which is significantly higher than the survival temperature level of cancer cells. So CNTs-PAMAM-Ag could be a promising photothermal agent to apply in future photothermal hyperthermia therapy to treat cancer. Moreover CNTs-PAMAM-Ag can synchronous trigger by a single wavelength (980 nm) laser system, so it could simplify the future therapeutic process.

Membrane heat shock protein 70: a theranostic target for cancer therapy

Members of the 70 kDa stress protein family are found in nearly all subcellular compartments of nucleated cells where they fulfil a number of chaperoning functions. Heat shock protein 70 (HSP70), also termed HSPA1A, the major stress-inducible member of this family is overexpressed in a large variety of different tumour types. Apart from its intracellular localization, a tumour-selective HSP70 membrane expression has been determined. A membrane HSP70–positive tumour phenotype is associated with aggressiveness and therapy resistance, but also serves as a recognition structure for targeted therapies. Furthermore, membrane-bound and extracellularly residing HSP70 derived from tumour cells play pivotal roles in eliciting anti-tumour immune responses. Herein, we want to shed light on the multiplicity of different activities of HSP70, depending on its intracellular, membrane and extracellular localization with the goal to use membrane HSP70 as a target for novel therapies including nanoparticle-based approaches for the treatment of cancer.

This article is part of the theme issue ‘Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective’.