Photosensitizer-conjugated magnetic nanoparticles for in vivo simultaneous magnetofluorescent imaging and targeting therapy

Reactive oxygen species-dependent nanomedicine therapeutic modalities for gastric cancer

Reactive oxygen species (ROS) play a double-edged role in gastric cancer (GC). Higher levels of ROS in tumor cells compared to normal cells facilitate tumor progression. Once ROS concentrations rise rapidly to toxic levels, they cause GC cell death, which is instead beneficial for GC treatment. Based on these functions, nano-delivery systems taking the therapeutic advantages of ROS have been widely employed in tumor therapy in recent years, overcoming the drawbacks of conventional drug delivery techniques, such as non-specific systemic effects. In this review, the precise impacts of ROS on GC have been detailed, along with ROS-based nanomedicine therapeutic schemes. These strategies mainly focused on the use of excess ROS in the tumor microenvironment for controlled drug release and a substantial enhancement of ROS concentrations for tumor killing. The challenges and opportunities for the advancement of these anticancer therapies are also emphasized.

Advancing gastric cancer treatment: nanotechnology innovations and future prospects

Gastric cancer (GC) is the fifth most common cancer worldwide, particularly prevalent in Asia, especially in China, where both its incidence and mortality rates are significantly high. Meanwhile, nanotechnology has demonstrated great potential in the treatment of GC. In particular, nanodrug delivery systems have improved therapeutic efficacy and targeting through various functional modifications, such as targeting peptides, tumor microenvironment responsiveness, and instrument-based methods. For instance, silica (SiO2) has excellent biocompatibility and can be used as a drug carrier, with its porous structure enhancing drug loading capacity. Polymer nanoparticles regulate drug release rates and mechanisms by altering material composition and preparation methods. Lipid nanoparticles efficiently encapsulate hydrophilic drugs and promote cellular uptake, while carbon-based nanoparticles can be used in biosensors and drug delivery. Targets such as integrins, HER2 receptors, and the tumor microenvironment have been used to improve drug efficacy in GC treatment. Nanodrug delivery techniques not only enhance drug efficacy and delivery capabilities but also selectively target tumor cells. Currently, there is a lack of systematic summarization and synthesis regarding the relationship between nanodrug delivery systems and GC treatment, which to some extent hinders researchers and clinicians from efficiently searching for and referencing related studies, thereby reducing work efficiency. This study aims to systematically summarize the existing research on the relationship between nanodrug delivery systems and GC treatment, making it easier for professionals to search and reference, and thereby promoting further research on the role of nanodrug delivery systems and their clinical applications in GC. This review discusses the applications of functionalized nanocarriers in the treatment of GC in recent years, including surface modifications with targeted markers, the combination of phototherapy, chemotherapy, and immunotherapy, along with their advantages and challenges. It also examines the future prospects of targeted nanomaterials in GC treatment. The review particularly focuses on the combined application of nanocarriers in multiple treatment modalities, such as phototherapy, chemotherapy, and immunotherapy, demonstrating their potential in multimodal treatments. Furthermore, it thoroughly explores the specific challenges that nanocarriers face in GC treatment, such as biocompatibility, drug release control, and clinical translation issues, while providing a systematic outlook on future developments. Additionally, this study emphasizes the potential value and feasibility of nanocarriers in clinical applications, contrasting with most reviews that focus on basic research. Through these innovations, we offer new perspectives and directions for the development of nanotechnology in the treatment of GC.

Mapping the intellectual structure and emerging trends for the application of nanomaterials in gastric cancer: A bibliometric study

BACKGROUND

Recent reviews have outlined the main nanomaterials used in relation to gastrointestinal tumors and described the basic properties of these materials. However, the research hotspots and trends in the application of nanomaterials in gastric cancer (GC) remain obscure.

AIM

To demonstrate the knowledge structure and evolutionary trends of research into the application of nanomaterials in GC.

METHODS

Publications related to the application of nanomaterials in GC were retrieved from the Web of Science Core Collection for this systematic review and bibliometric study. VOSviewer and CiteSpace were used for bibliometric and visualization analyses.

RESULTS

From 2000 to 2022, the application of nanomaterials in GC developed rapidly. The keyword co-occurrence analysis showed that the related research topics were divided into three clusters: (1) The application of nanomaterials in GC treatment; (2) The application and toxicity of nanomaterials in GC diagnosis; and (3) The effects of nanomaterials on the biological behavior of GC cells. Complexes, silver nanoparticles, and green synthesis are the latest high-frequency keywords that represent promising future research directions.

CONCLUSION

The application of nanomaterials in GC diagnosis and treatment and the mechanisms of their effects on GC cells have been major themes in this field over the past 23 years.

Double-layer hollow mesoporous silica nanoparticles for ultrasound-guided photodynamic treatment

Cervical carcinoma persists as a major global public health burden. While conventional therapeutic modalities inevitably cause ablation of adjacent non-tumorous tissues, photodynamic therapy (PDT) offers a targeted cytotoxic strategy through a photosensitizing agent (PS). However, the hydrophobicity and lack of selective accumulation of promising PS compounds such as zinc(II) phthalocyanine (ZnPc) impedes their clinical translation as standalone agents. The present study sought to incorporate ZnPc within double-layer hollow mesoporous silica nanoparticles (DHMSN) as nanocarriers to enhance aqueous dispersibility and tumor specificity. Owing to their compartmentalized design, the hollow mesoporous silica nanoparticles (HMSN) demonstrated enhanced ultrasonic imaging contrast. Combined with the vaporization of the perfluorocarbon perfluoropentane (PFP), the HMSN-encapsulated ZnPc enabled real-time ultrasound monitoring of PDT treatment.In vivo, the innate thermal energy induced vaporization of the DHMSN-carried PFP to significantly amplify ultrasound signals from the tumor site. Results demonstrated biocompatibility, efficient PFP microbubble generation, and robust photocatalytic activity. Collectively, this investigation establishes ultrasound-guided PDT utilizing multi-layer HMSN as a targeted therapeutic strategy for cervical malignancies with mitigated toxicity.

Nanocarriers address intracellular barriers for efficient drug delivery, overcoming drug resistance, subcellular targeting and controlled release

The cellular barriers are major bottlenecks for bioactive compounds entering into cells to accomplish their biological functions, which limits their biomedical applications. Nanocarriers have demonstrated high potential and benefits for encapsulating bioactive compounds and efficiently delivering them into target cells by overcoming a cascade of intracellular barriers to achieve desirable therapeutic and diagnostic effects. In this review, we introduce the cellular barriers ahead of drug delivery and nanocarriers, as well as summarize recent advances and strategies of nanocarriers for increasing internalization with cells, promoting intracellular trafficking, overcoming drug resistance, targeting subcellular locations and controlled drug release. Lastly, the future perspectives of nanocarriers for intracellular drug delivery are discussed, which mainly focus on potential challenges and future directions. Our review presents an overview of intracellular drug delivery by nanocarriers, which may encourage the future development of nanocarriers for efficient and precision drug delivery into a wide range of cells and subcellular targets.

Recent developments in photodynamic therapy and its application against multidrug resistant cancers

Recently, photodynamic therapy (PDT) has received a lot of attention for its potential use in cancer treatment. It enables the therapy of a multifocal disease with the least amount of tissue damage. The most widely used prodrug is 5-aminolevulinic acid, which undergoes heme pathway conversion to protoporphyrin IX, which acts as a photosensitizer (PS). Additionally, hematoporphyrin, bacteriochlorin, and phthalocyanine are also studied for their therapeutic potential in cancer. Unfortunately, not every patient who receives PDT experiences a full recovery. Resistance to different anticancer treatments is commonly observed. A few of the resistance mechanisms by which cancer cells escape therapeutics are genetic factors, drug-drug interactions, impaired DNA repair pathways, mutations related to inhibition of apoptosis, epigenetic pathways, etc. Recently, much research has been conducted to develop a new generation of PS based on nanomaterials that could be used to overcome cancer cells' multidrug resistance (MDR). Various metal-based, polymeric, lipidic nanoparticles (NPs), dendrimers, etc, have been utilized in the PDT application against cancer. This article discusses the detailed mechanism by which cancer cells evolve towards MDR as well as recent advances in PDT-based NPs for use against multidrug-resistant cancers.

Application of near-infrared fluorescence imaging in theranostics of gastrointestinal tumors

Gastrointestinal cancers have become an important cause of cancer-related death in humans. Improving the early diagnosis rate of gastrointestinal tumors and improving the effect of surgical treatment can significantly improve the survival rate of patients. The conventional diagnostic method is high-definition white-light endoscopy, which often leads to missed diagnosis. For surgical treatment, intraoperative tumor localization and post-operative anastomotic state evaluation play important roles in the effect of surgical treatment. As a new imaging method, near-infrared fluorescence imaging (NIRFI) has its unique advantages in the diagnosis and auxiliary surgical treatment of gastrointestinal tumors due to its high sensitivity and the ability to image deep tissues. In this review, we focus on the latest advances of NIRFI technology applied in early diagnosis of gastrointestinal tumors, identification of tumor margins, identification of lymph nodes, and assessment of anastomotic leakage. In addition, we summarize the advances of NIRFI systems such as macro imaging and micro imaging systems, and also clearly describe the application process of NIRFI from system to clinical application, and look into the prospect of NIRFI applied in the theranostics of gastrointestinal tumors.

A tumor targeted antifouling upconversion nanoplatform for fluorescence imaging and precise photodynamic therapy triggered by NIR laser

Photodynamic therapy (PDT) has been considered as a promising treatment in the biomedical field because of low toxicity to normal tissues and minor trauma area. However, the PDT effect of materials is greatly affected by many factors, such as nonspecific adsorption and poor light penetration, etc. In this work, an intelligent nano platform has been constructed based on upconversion nanoparticles (UCNPs) loaded with a large amount of photosensitizers Ce6, which could specifically light up tumor tissues and stimulate the production of reactive oxygen species (ROS) under 980 nm near-infrared (NIR) irradiation, exhibiting a conspicuous imaging and therapeutic effect of PDT treatment for deep tumors. An excellent anti-fouling performance in complex biological substrate was obtained upon the judicious introduction of anti-fouling peptide, which also contributed to the improved PDT efficiency. In addition, the specificity of nanoplatform to malignant breast cancer cells was realized by modification of polypeptide targeting for HER2. This anti-fouling nanoplatform provided an original paradigm for the development of fluorescence imaging and PDT for deep tumor tissue with high targeting and therapeutic efficacy, promising to be used in the early therapy of malignant breast cancer specifically.

Research trends on nanomaterials in gastric cancer: a bibliometric analysis from 2004 to 2023

BACKGROUND

Gastric cancer is one of the leading causes of cancer-related deaths worldwide. In recent years, an increasing number of studies aimed at designing and developing nanomaterials for use in diagnosing and treating gastric cancer have been conducted. In this study, we aimed to comprehensively assess the current status and trends of the research on the application of nanomaterials in gastric cancer through a bibliometric analysis.

METHODS

Studies focusing on nanomaterials and gastric cancer were retrieved from the Web of Science Core Collection database and relevant articles were selected for inclusion in the study according to the inclusion criteria. Bibliometric and visual analysis of the included publications was performed using VOSviewer and CiteSpace.

RESULTS

A total of 793 studies were included. An increase in annual publications was observed from 2004 to 2023. China, Iran and the USA were the dominant countries in this field, accounting for 66.1%, 11.5% and 7.2% of publications, respectively. Shanghai Jiao Tong University and Cui DX were the most influential institution and author, respectively. The International Journal of Nanomedicine was the most prolific journal; Biomaterials was the most cited and most cocited journal. Nanomaterial-related drug delivery and anticancer mechanisms were found to be the most widely researched aspects, and green synthesis and anticancer mechanisms are recent research hotspots.

CONCLUSION

In this study, we summarized the characteristics of publications and identified the most influential countries, institutions, authors, journals, hot topics and trends regarding the application of nanomaterials in gastric cancer.

Combinations of Photodynamic Therapy with Other Minimally Invasive Therapeutic Technologies against Cancer and Microbial Infections

The rapid rise in research and development following the discovery of photodynamic therapy to establish novel photosensitizers and overcome the limitations of the technology soon after its clinical translation has given rise to a few significant milestones. These include several novel generations of photosensitizers, the widening of the scope of applications, leveraging of the offerings of nanotechnology for greater efficacy, selectivity for the disease over host tissue and cells, the advent of combination therapies with other similarly minimally invasive therapeutic technologies, the use of stimulus-responsive delivery and disease targeting, and greater penetration depth of the activation energy. Brought together, all these milestones have contributed to the significant enhancement of what is still arguably a novel technology. Yet the major applications of photodynamic therapy still remain firmly located in neoplasms, from where most of the new innovations appear to launch to other areas, such as microbial, fungal, viral, acne, wet age-related macular degeneration, atherosclerosis, psoriasis, environmental sanitization, pest control, and dermatology. Three main value propositions of combinations of photodynamic therapy include the synergistic and additive enhancement of efficacy, the relatively low emergence of resistance and its rapid development as a targeted and high-precision therapy. Combinations with established methods such as chemotherapy and radiotherapy and demonstrated applications in mop-up surgery promise to enhance these top three clinical tools. From published in vitro and preclinical studies, clinical trials and applications, and postclinical case studies, seven combinations with photodynamic therapy have become prominent research interests because they are potentially easily applied, showing enhanced efficacy, and are rapidly translating to the clinic. These include combinations with chemotherapy, photothermal therapy, magnetic hyperthermia, cold plasma therapy, sonodynamic therapy, immunotherapy, and radiotherapy. Photochemical internalization is a critical mechanism for some combinations.

Dual-Drug-Loaded Topical Delivery of Photodynamically Active Lipid-Based Formulation for Combination Therapy of Cutaneous Melanoma

Topical administration of anti-cancer drugs along with photodynamically active molecules is a non-invasive approach, which stands to be a promising modality for treating aggressive cutaneous melanomas with the added advantage of high patient compliance. However, the efficiency of delivering drugs topically is limited by several factors, such as penetration of the drug across skin layers at the tumor site and limited light penetrability. In this study, curcumin, an active anti-cancer agent, and chlorin e6, a photoactivable molecule, were encapsulated into lipidic nanoparticles that produced reactive oxygen species (ROS) when activated at 665 nm by near-infrared (NIR) light. The optimized lipidic nanoparticle containing curcumin and chlorin e6 exhibited a particle size of less than 100 nm. The entrapment efficiency for both molecules was found to be 81%. The therapeutic efficacy of the developed formulation was tested on B16F10 and A431 cell lines via cytotoxicity evaluation, combination index, cellular uptake, nuclear staining, DNA fragmentation, ROS generation, apoptosis, and cell cycle assays under NIR irradiation (665 nm). Co-delivering curcumin and chlorin e6 exhibited higher cellular uptake, better cancer growth inhibition, and pronounced apoptotic events compared to the formulation having the free drug alone. The study results depicted that topical application of this ROS-generating dual-drug-loaded lipidic nanoparticles incorporated in SEPINEO gel achieved better permeation (80 ± 2.45%) across the skin, and exhibited the improved skin retention and a synergistic effect as well. The present work introduces photo-triggered ROS-generating dual-drug-based lipidic nanoparticles, which are simple and efficient to develop and exhibit synergistic therapeutic effects against cutaneous melanoma.

BioMOF-Based Anti-Cancer Drug Delivery Systems

A variety of nanomaterials have been developed specifically for biomedical applications, such as drug delivery in cancer treatment. These materials involve both synthetic and natural nanoparticles and nanofibers of varying dimensions. The efficacy of a drug delivery system (DDS) depends on its biocompatibility, intrinsic high surface area, high interconnected porosity, and chemical functionality. Recent advances in metal-organic framework (MOF) nanostructures have led to the achievement of these desirable features. MOFs consist of metal ions and organic linkers that are assembled in different geometries and can be produced in 0, 1, 2, or 3 dimensions. The defining features of MOFs are their outstanding surface area, interconnected porosity, and variable chemical functionality, which enable an endless range of modalities for loading drugs into their hierarchical structures. MOFs, coupled with biocompatibility requisites, are now regarded as highly successful DDSs for the treatment of diverse diseases. This review aims to present the development and applications of DDSs based on chemically-functionalized MOF nanostructures in the context of cancer treatment. A concise overview of the structure, synthesis, and mode of action of MOF-DDS is provided.

Bioimaging Probes Based on Magneto-Fluorescent Nanoparticles

Novel nanomaterials are of interest in biology, medicine, and imaging applications. Multimodal fluorescent-magnetic nanoparticles demand special attention because they have the potential to be employed as diagnostic and medication-delivery tools, which, in turn, might make it easier to diagnose and treat cancer, as well as a wide variety of other disorders. The most recent advancements in the development of magneto-fluorescent nanocomposites and their applications in the biomedical field are the primary focus of this review. We describe the most current developments in synthetic methodologies and methods for the fabrication of magneto-fluorescent nanocomposites. The primary applications of multimodal magneto-fluorescent nanoparticles in biomedicine, including biological imaging, cancer treatment, and drug administration, are covered in this article, and an overview of the future possibilities for these technologies is provided.

Smart Metabolism Nanovalve Reprograms Cancer Energy Homeostasis for Maximizing Photometabolism Therapy

Better understanding of important roles of metabolic reprogramming in therapeutic resistance provides insights into advancing cancer treatment. Herein, we present a photoactive metabolic reprogramming strategy (termed as photometabolism therapy, PMT), in which photoregulation of mitochondria leads to cancer cell metabolic crisis, and consequently overcomes therapeutic resistance while improving treatment efficacy. In specific, a stimuli-responsive metabolism NanoValve is developed for improving cascade cancer therapy through blocking mitochondrial energy supply. NanoValve is composed of an onion-like architecture with a gold nanorod core, a mesoporous silica shell encapsulating photosensitizer chlorin e6 and oxygen-saturated perfluorocarbon, and cationic liposomal coating with MMP2-cleavable polyethylene glycol corona, which together initiate mitochondria-specific PMT. NanoValve selectively responds to tumor-overexpressed MMP2 and achieves size decrease and charge reversal, which consequently enhances tumor penetration, cancer cell uptake, endosome escape, and most critically, mitochondrial accumulation. Importantly, NanoValve-mediated phototherapy can strongly destruct mitochondrial energy metabolism, thereby minimizing therapy resistance. Particularly, perfluorocarbon supplies oxygen to further overcome the tumor hypoxia-associated therapeutic barrier and maximizes synergistic anticancer effects. In vivo studies show that NanoValve can effectively eliminate tumors without side effects, thereby dramatically prolonging the survival of tumor-bearing mice. Thus, NanoValve provides a modular PMT approach and has the potential of advancing the treatment of malignancy.

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (¹O₂) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.

Enhanced Photodynamic Therapy: A Review of Combined Energy Sources

Photodynamic therapy (PDT) has been used in recent years as a non-invasive treatment for cancer, due to the side effects of traditional treatments such as surgery, radiotherapy, and chemotherapy. This therapeutic technique requires a photosensitizer, light energy, and oxygen to produce reactive oxygen species (ROS) which mediate cellular toxicity. PDT is a useful non-invasive therapy for cancer treatment, but it has some limitations that need to be overcome, such as low-light-penetration depths, non-targeting photosensitizers, and tumor hypoxia. This review focuses on the latest innovative strategies based on the synergistic use of other energy sources, such as non-visible radiation of the electromagnetic spectrum (microwaves, infrared, and X-rays), ultrasound, and electric/magnetic fields, to overcome PDT limitations and enhance the therapeutic effect of PDT. The main principles, mechanisms, and crucial elements of PDT are also addressed.

A Nanomedicine Structure-Activity Framework for Research, Development, and Regulation of Future Cancer Therapies

Despite their clinical success in drug delivery applications, the potential of theranostic nanomedicines is hampered by mechanistic uncertainty and a lack of science-informed regulatory guidance. Both the therapeutic efficacy and the toxicity of nanoformulations are tightly controlled by the complex interplay of the nanoparticle's physicochemical properties and the individual patient/tumor biology; however, it can be difficult to correlate such information with observed outcomes. Additionally, as nanomedicine research attempts to gradually move away from large-scale animal testing, the need for computer-assisted solutions for evaluation will increase. Such models will depend on a clear understanding of structure-activity relationships. This review provides a comprehensive overview of the field of cancer nanomedicine and provides a knowledge framework and foundational interaction maps that can facilitate future research, assessments, and regulation. By forming three complementary maps profiling nanobio interactions and pathways at different levels of biological complexity, a clear picture of a nanoparticle's journey through the body and the therapeutic and adverse consequences of each potential interaction are presented.

Modified hollow mesoporous silica nanoparticles as immune adjuvant-nanocarriers for photodynamically enhanced cancer immunotherapy

Nanomedicine has demonstrated great potential in enhancing cancer immunotherapy. However, nanoparticle (NP)-based immunotherapy still has limitations in inducing effective antitumor responses and inhibiting tumor metastasis. Herein, polyethylenimine (PEI) hybrid thin shell hollow mesoporous silica NPs (THMSNs) were applied as adjuvant-nanocarriers and encapsulated with very small dose of photosensitizer chlorine e6 (Ce6) to realize the synergy of photodynamic therapy (PDT)/immunotherapy. Through PEI etching, the obtained Ce6@THMSNs exhibited enhanced cellular internalization and endosome/lysosome escape, which further improved the PDT efficacy of Ce6@THMSNs in destroying tumor cells. After PDT treatment, the released tumor-associated antigens with the help of THMSNs as adjuvants promoted dendritic cells maturation, which further boosted CD8⁺ cytotoxic T lymphocytes activation and triggered antitumor immune responses. The in vivo experiments demonstrated the significant potency of Ce6@THMSNs-based PDT in obliterating primary tumors and inducing persistent tumor-specific immune responses, thus preventing distant metastasis. Therefore, we offer a THMSNs-mediated and PDT-triggered nanotherapeutic system with immunogenic property, which can elicit robust antitumor immunity and is promising for future clinical development of immunotherapy.

Porphyrin-Based Nanoparticles: A Promising Phototherapy Platform

Phototherapy, including photodynamic therapy and photothermal therapy, is an emerging form of non-invasive treatment. The combination of imaging technology and phototherapy is becoming an attractive development in the treatment of cancer, as it allows for highly effective therapeutic results through image-guided phototherapy. Porphyrins have attracted significant interest in the treatment and diagnosis of cancer due to their excellent phototherapeutic effects in phototherapy and their remarkable imaging capabilities in fluorescence imaging, magnetic resonance imaging and photoacoustic imaging. However, porphyrins suffer from poor water solubility, low near-infrared absorption and insufficient tumor accumulation. The development of nanotechnology provides an effective way to improve the bioavailability, phototherapeutic effect and imaging capability of porphyrins. This review highlights the research results of porphyrin-based small molecule nanoparticles in phototherapy and image-guided phototherapy in the last decade and discusses the challenges and directions for the development of porphyrin-based small molecule nanoparticles in phototherapy.

Designing the Surface Chemistry of Inorganic Nanocrystals for Cancer Imaging and Therapy

Inorganic nanocrystals, such as gold, iron oxide and semiconductor quantum dots, offer promising prospects for cancer diagnostics, imaging and therapy, due to their specific plasmonic, magnetic or fluorescent properties. The organic coating, or surface ligands, of these nanoparticles ensures their colloidal stability in complex biological fluids and enables their functionalization with targeting functions. It also controls the interactions of the nanoparticle with biomolecules in their environment. It therefore plays a crucial role in determining nanoparticle biodistribution and, ultimately, the imaging or therapeutic efficiency. This review summarizes the various strategies used to develop optimal surface chemistries for the in vivo preclinical and clinical application of inorganic nanocrystals. It discusses the current understanding of the influence of the nanoparticle surface chemistry on its colloidal stability, interaction with proteins, biodistribution and tumor uptake, and the requirements to develop an optimal surface chemistry.

New Generation of Photosensitizers Based on Inorganic Nanomaterials

Advance of nanomaterials and nanotechnology has offered new possibilities for photodynamic therapy (PDT). Large amount of different kinds of sensitizers and targeting moieties can now be loaded in nanometer's volume, which not only results in the improvement of the efficacy of PDT, but also enables the control of image-guided PDT with unprecedented precision and variation. This chapter shall overview the recently most studied inorganic nanomaterials for PDT.

Multifunctional Iron Oxide Magnetic Nanoparticles for Biomedical Applications: A Review

Due to their good magnetic properties, excellent biocompatibility, and low price, magnetic iron oxide nanoparticles (IONPs) are the most commonly used magnetic nanomaterials and have been extensively explored in biomedical applications. Although magnetic IONPs can be used for a variety of applications in biomedicine, most practical applications require IONP-based platforms that can perform several tasks in parallel. Thus, appropriate engineering and integration of magnetic IONPs with different classes of organic and inorganic materials can produce multifunctional nanoplatforms that can perform several functions simultaneously, allowing their application in a broad spectrum of biomedical fields. This review article summarizes the fabrication of current composite nanoplatforms based on integration of magnetic IONPs with organic dyes, biomolecules (e.g., lipids, DNAs, aptamers, and antibodies), quantum dots, noble metal NPs, and stimuli-responsive polymers. We also highlight the recent technological advances achieved from such integrated multifunctional platforms and their potential use in biomedical applications, including dual-mode imaging for biomolecule detection, targeted drug delivery, photodynamic therapy, chemotherapy, and magnetic hyperthermia therapy.

Recent development for biomedical applications of magnetic nanoparticles

In recent decades, the use of engineered nanoparticles has been increasing in various sectors, including biomedicine, diagnosis, water treatment, and environmental remediation leading to significant public concerns. Among these nanoparticles, magnetic nanoparticles (MNPs) have gained many attentions in medicine, pharmacology, drug delivery system, molecular imaging, and bio-sensing due to their various properties. In addition, various studies have reviewed MNPs main applications in the biomedical engineering area with intense progress and recent achievements. Nanoparticles, especially the magnetic nanoparticles, have recently been confirmed with excellent antiviral activity against different viruses, including SARS-CoV-2(Covid-19) and their recent development against Covid-19 also has also been discussed. This review aims to highlight the recent development of the magnetic nanoparticles and their biomedical applications such as diagnosis of diseases, molecular imaging, hyperthermia, bio-sensing, gene therapy, drug delivery and the diagnosis of Covid-19.

Recent Advances in Photosensitizers as Multifunctional Theranostic Agents for Imaging-Guided Photodynamic Therapy of Cancer

In recent years tremendous effort has been invested in the field of cancer diagnosis and treatment with an overall goal of improving cancer management, therapeutic outcome, patient survival, and quality of life. Photodynamic Therapy (PDT), which works on the principle of light-induced activation of photosensitizers (PS) leading to Reactive Oxygen Species (ROS) mediated cancer cell killing has received increased attention as a promising alternative to overcome several limitations of conventional cancer therapies. Compared to conventional therapies, PDT offers the advantages of selectivity, minimal invasiveness, localized treatment, and spatio-temporal control which minimizes the overall therapeutic side effects and can be repeated as needed without interfering with other treatments and inducing treatment resistance. Overall PDT efficacy requires proper planning of various parameters like localization and concentration of PS at the tumor site, light dose, oxygen concentration and heterogeneity of the tumor microenvironment, which can be achieved with advanced imaging techniques. Consequently, there has been tremendous interest in the rationale design of PS formulations to exploit their theranostic potential to unleash the imperative contribution of medical imaging in the context of successful PDT outcomes. Further, recent advances in PS formulations as activatable phototheranostic agents have shown promising potential for finely controlled imaging-guided PDT due to their propensity to specifically turning on diagnostic signals simultaneously with photodynamic effects in response to the tumor-specific stimuli. In this review, we have summarized the recent progress in the development of PS-based multifunctional theranostic agents for biomedical applications in multimodal imaging combined with PDT. We also present the role of different imaging modalities; magnetic resonance, optical, nuclear, acoustic, and photoacoustic in improving the pre-and post-PDT effects. We anticipate that the information presented in this review will encourage future development and design of PSs for improved image-guided PDT for cancer treatment.

A hybrid nanozymes in situ oxygen supply synergistic photothermal/chemotherapy of cancer management

Hypoxia in the solid tumor microenvironment (TME) can easily induce tumor recurrence, metastasis, and drug resistance. The use of man-made nanozymes is considered to be an effective strategy for regulating hypoxia in the TME. Herein, Ru@MnO2 nanozymes were constructed via an in situ reduction method, and they showed excellent photothermal conversion efficiency and catalytic activity. The anti-tumor drug DOX with fluorescence was loaded on the Ru@MnO2 nanozymes, and an erythrocyte membrane was further coated on the surface of the Ru@MnO2 nanozymes to construct nanozymes with on-demand release abilities. The erythrocyte membrane (RBCm) enhances the biocompatibility of the Ru@MnO2 nanozymes and prolongs their circulation time in the blood. Ru@MnO2 nanozymes can catalyze endogenous H2O2 to produce O2 to relieve hypoxia in the TME to enhance the efficacy of the photothermal therapy/chemotherapy of cancer. In vitro studies confirmed that the Ru@MnO2 nanozymes showed good tumor penetration abilities and a synergistic anti-tumor effect. Importantly, both in vivo and in vitro studies have confirmed that the oxygen supply in situ enhanced the efficacy of the PTT/chemotherapy of cancer. Accordingly, this study demonstrated that Ru@MnO2 nanozymes can be used as an effective integrated system allowing catalysis, photothermal therapy, and chemotherapy for cancer management.

Periodic Mesoporous Ionosilica Nanoparticles for Green Light Photodynamic Therapy and Photochemical Internalization of siRNA

We report periodic mesoporous ionosilica nanoparticles (PMINPs) as versatile nano-objects for imaging, photodynamic therapy (PDT), and efficient adsorption and delivery of small interfering RNA (siRNA) into breast cancer cells. In order to endow these nanoparticles with PDT and siRNA photochemical internalization (PCI) properties, a porphyrin derivative was integrated into the ionosilica framework. For this purpose, we synthesized PMINPs via hydrolysis-cocondensation procedures from oligosilylated ammonium and porphyrin precursors. The formation of these nano-objects was proved by transmission electron microscopy. The formed nanoparticles were then thoroughly characterized via solid-state NMR, nitrogen sorption, dynamic light scattering, and UV-vis and fluorescence spectroscopies. Our results indicate the formation of highly porous nanorods with a length of 108 ± 9 nm and a width of 54 ± 4 nm. A significant PDT effect of type I mechanism (95 ± 2.8% of cell death) was observed upon green light irradiation in nanoparticle-treated breast cancer cells, while the blue light irradiation caused a significant phototoxic effect in non-treated cells. Furthermore, PMINPs formed stable complexes with siRNA (up to 24 h), which were efficiently internalized into the cells after 4 h of incubation mostly with the energy-dependent endocytosis process. The PCI effect was obvious with green light irradiation and successfully led to 83 ± 1.1% silencing of the luciferase gene in luciferase-expressing breast cancer cells, while no gene silencing effect was observed with blue light irradiation. The present work highlights the high potential of porphyrin-doped PMINPs as multifunctional nanocarriers for nucleic acids, such as siRNA, with a triple ability to perform imaging, PDT, and PCI.

Dual-Stimuli-Responsive Nanotheranostics for Dual-Targeting Photothermal-Enhanced Chemotherapy of Tumor

Stimuli-responsive nanotheranostics have been widely explored for precision medicine. Here, we developed a pH/light dual-stimuli-responsive nanotheranostic agent for biological/physical dual-targeting photothermal-enhanced chemotherapy of U87MG tumor. This nanotheranostic agent was composed of the RGD (Arg-Gly-Asp) peptide, melanin-coated magnetic nanoparticles (MMNs), doxorubicin (DOX), and indocyanine green (ICG), denoted as RMDI. The tumor accumulation of RMDI was simultaneously improved through biological active targeting by RGD and physical magnetic targeting by an external magnetic field at tumor tissues, which was proven by in vivo photoacoustic/magnetic resonance/fluorescence (PA/MR/FL) trimodal imaging. Under dual stimuli of the tumor acidic microenvironment and laser irradiation, both DOX and ICG were released in a controlled fashion, demonstrating impressive therapeutic outcomes against U87MG tumor both in vitro and in vivo, respectively. Owing to the synergistic photothermal/chemotherapy, the dual-stimuli-responsive and dual-targeting nanotheranostic agent completely ablated U87MG tumor in vivo without any tumor recurrence and biotoxicity. This nanotheranostic agent exhibited great potential in multimodal imaging-guided synergistic therapy of cancer.

Light-Interacting iron-based nanomaterials for localized cancer detection and treatment

To improve the prognosis of cancer patients, methods of local cancer detection and treatment could be implemented. For that, iron-based nanomaterials (IBN) are particularly well-suited due to their biocompatibility and the various ways in which they can specifically target a tumor, i.e. through passive, active or magnetic targeting. Furthermore, when it is needed, IBN can be associated with well-known fluorescent compounds, such as dyes, clinically approved ICG, fluorescent proteins, or quantum dots. They may also be excited and detected using well-established optical methods, relying on scattering or fluorescent mechanisms, depending on whether IBN are associated with a fluorescent compound or not. Systems combining IBN with optical methods are diverse, thus enabling tumor detection in various ways. In addition, these systems provide a wealth of information, which is inaccessible with more standard diagnostic tools, such as single tumor cell detection, in particular by combining IBN with near-field scanning optical microscopy, dark-field microscopy, confocal microscopy or super-resolution microscopy, or the highlighting of certain dynamic phenomena such as the diffusion of a fluorescent compound in an organism, e.g. using fluorescence lifetime imaging, fluorescence resonance energy transfer, fluorescence anisotropy, or fluorescence tomography. Furthermore, they can in some cases be complemented by a therapeutic approach to destroy tumors, e.g. when the fluorescent compound is a drug, or when a technique such as photo-thermal or photodynamic therapy is employed. This review brings forward the idea that iron-based nanomaterials may be associated with various optical techniques to form a commercially available toolbox, which can serve to locally detect or treat cancer with a better efficacy than more standard medical approaches. STATEMENT OF SIGNIFICANCE: New tools should be developed to improve cancer treatment outcome. For that, two closely-related aspects deserve to be considered, i.e. early tumor detection and local tumor treatment. Here, I present various types of iron-based nanomaterials, which can achieve this double objective when they interact with a beam of light under specific and accurately chosen conditions. Indeed, these materials are biocompatible and can be used/combined with most standard microscopic/optical methods. Thus, these systems enable on the one hand tumor cell detection with a high sensitivity, i.e. down to single tumor cell level, and on the other hand tumor destruction through various mechanisms in a controlled and localized manner by deciding whether or not to apply a beam of light and by having these nanomaterials specifically target tumor cells.

A novel strategy for tumor therapy: targeted, PAA-functionalized nano-hydroxyapatite nanomedicine

The rapid development of nanotechnology has provided new strategies for the treatment of tumors. Nano-scale hydroxyapatite (HAP), as the main component of hard tissues in humans and vertebrates, have been found to specifically inhibit tumor cells. However, achieving controllable synthesis of HAP and endowing it with cancer cell-targeting properties remain enormous challenges. To solve this problem, we developed polyacrylic acid-coordinated hydroxyapatite nanoparticles (HAP-PAA) and further chemically grafted them with folic acid (HAP-PAA-FA) for cancer treatment in this study. The nucleation sites and steric hindrance provided by the PAA greatly inhibited the agglomeration of the nanoparticles, and at the same time, the excess functional groups further modified the surface of nanoparticles to achieve targeting efficiency. The spherical, low-crystallinity HAP-PAA nanoparticles exhibited good tumor cell lethality. After grafting the nanoparticles with folic acid for molecular targeting, their cellular uptake and specific killing ability of tumor cells were further enhanced. The HAP-PAA-FA nanoparticle system exerted a regulatory effect on the tumor microenvironment and had good biological safety. All the above results indicate that this research will broaden the application of hydroxyapatite in tumor treatment.

Functional Transdermal Nanoethosomes Enhance Photodynamic Therapy of Hypertrophic Scars via Self-Generating Oxygen

Photodynamic therapy (PDT) is a new therapeutic strategy for hypertrophic scars (HSs), and nanoethosomes (ES) have attracted considerable attention as an efficient transdermal delivery system for PDT of HSs (HS-PDT). However, the delivery of photosensitizers and the hypoxic microenvironment of HSs limit HS-PDT efficacy. Consequently, functional transdermal ES (A/A-ES) that are loaded with the photosensitizer, 5-aminolevulinic acid (ALA), and immobilized nanoenzyme Au nanoclusters (ANCs) within the ES surface have been developed that exhibit superior co-delivery characteristics and produce catalase that enhances HS-PDT efficacy. The unique structure of A/A-ES enables them to co-deliver ALA and ANCs into the HS tissue and to efficiently decompose the endogenous hydrogen peroxide in the HS to generate oxygen. The findings from in vitro and in vivo experiments demonstrated that A/A-ES efficiently co-delivered ALA and ANCs into the HS tissue and that they improved the hypoxic microenvironment of the HS. Systematic assessments reveal that A/A-ES enhance HS-PDT efficacy and that they are highly effective at improving the morphology and promoting HS fibroblast apoptosis and the rearrangement of collagen. These works give rise to an effective treatment option for HSs that integrates the transdermal co-delivery of ALA and nanoenzymes, thereby enabling them to exert their respective beneficial effects, and they highlight the enhancement of HS-PDT efficacy via self-generating oxygen.

Downregulation of Rac1/PAK1/LIMK1/cofilin signaling pathway in colon cancer SW620 cells treated with Chlorin e6 photodynamic therapy

BACKGROUND

Colorectal cancer is one of the most common gastrointestinal malignancies. Photodynamic therapy (PDT) is a novel and non-invasive treatment for tumors as PDT features small trauma, good applicability, andaccurate targeting. PDT may also be a potential treatment for colon cancer as itmay may induce suppressive effects on metastatic potential.. However, the molecular mechanism of the Chlorin e6 Photodynamic therapy (Ce6-PDT) inhibiting the migration of human colon cancer SW620 cells remains unclear.

METHODS

Scratch wound healing assay, scanning electron microscope, MTT, immunofluorescence and laser confocal technique were used to investigate the suppressive effects of Ce6-PDT on the SW620 cells migration, pseudopodia, viability and the actin cytoskeleton. The effect of Ce6-PDT on actin-Filaments and signaling molecules of the Rac1/PAK1/LIMK1/cofilin signaling pathway in SW620 cells were examined by western blot analysis. RNA interference (RNAi) technology was used to establish siRNA-Rac1/SW620 cells. The combined effects of Ce6-PDT and RNAi on colon cancer SW620 cells was investigated by the same technology and methods mentioned above to clarify the signal transduction effect of Rac1/PAK1/LIMK1/cofilin signaling pathway in Ce6-PDT caused inhibition of SW620 cell migration.

RESULTS

The healing and migration rate of the SW620 cells was significantly reduced and the cell pseudopodia were reduced or disappeared by Ce6-PDT. The Immunofluorescence and western blot analysis results showed that Ce6-PDT destroy microfilament's original structure and significantly downregulated F-actin protein expression. The Rac1/PAK1/LIMK1/cofilin signaling pathway was downregulated by Ce6-PDT. Furthermore, the RNAi significantly strengthened the effect of Ce6-PDT on colon cancer SW620 cells migration.

CONCLUSIONS

Actin cytoskeleton and protrusions of SW620 cells correlate with its migration ability. Ce6-PDT suppresses SW620 cells migration by downregulating the Rac1/PAK1/LIMK1/cofilin signaling pathway, and its suppressive effect was enhanced by knocking down Rac1 gene expression.

Conjugated Photosensitizers for Imaging and PDT in Cancer Research

Early cancer detection and perfect understanding of the disease are imperative toward efficient treatments. It is straightforward that, for choosing a specific cancer treatment methodology, diagnostic agents undertake a critical role. Imaging is an extremely intriguing tool since it assumes a follow up to treatments to survey the accomplishment of the treatment and to recognize any conceivable repeating injuries. It also permits analysis of the disease, as well as to pursue treatment and monitor the possible changes that happen on the tumor. Likewise, it allows screening the adequacy of treatment and visualizing the state of the tumor. Additionally, when the treatment is finished, observing the patient is imperative to evaluate the treatment methodology and adjust the treatment if necessary. The goal of this review is to present an overview of conjugated photosensitizers for imaging and therapy.

Synthesis and toxicity assessment of Fe3O4 NPs grafted by ∼ NH2-Schiff base as anticancer drug: modeling and proposed molecular mechanism through docking and molecular dynamic simulation

Superparamagnetic iron oxide nanoparticles have been synthesized using chain length of (3-aminopropyl) triethoxysilane for cancer therapy. First, we have developed a layer by layer functionalized with grafting 2,4-toluene diisocyanate as a bi-functional covalent linker onto a nano-Fe₃O₄ support. Then, they were characterized by Fourier transform infrared, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and VSM techniques. Finally, all nanoparticles with positive or negative surface charges were tested against K562 (myelogenous leukemia cancer) cell lines to demonstrate their therapeutic efficacy by MTT assay test. We found that the higher toxicity of Fe₃O₄@SiO₂@APTS ∼ Schiff base-Cu(II) (IC₅₀: 1000 μg/mL) is due to their stronger in situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. For first time, the molecular dynamic simulations of all compounds were carried out afterwards optimizing using MM+, Semi-empirical (AM1) and Ab-initio (STO-3G), Forcite Gemo Opt, Forcite Dynamics, Forcite Energy and CASTEP in Materials studio 2017. The energy (eV), space group, lattice parameters (Å), unit cell parameters (Å), and electron density of the predicted structures were taken from the CASTEP module of Materials Studio. The docking methods were used to predict the DNA binding affinity, ribonucleotide reductase, and topoisomerase II.

Synergistic transdermal delivery of nanoethosomes embedded in hyaluronic acid nanogels for enhancing photodynamic therapy

Photodynamic therapy (PDT) is a new therapeutic strategy for hypertrophic scars (HS), but it is limited by low drug utilization. Transdermal delivery based on nanoethosomes (ES) has attracted considerable attention as a potential clinical strategy in PDT treating HS. However, free ES are unsatisfactory due to their instability and non-targeting, which causes non-effective delivery and low drug utilization. Herein, 5-aminolevulinic acid (ALA)-loaded ES (ES-ALA) embedded in hyaluronic acid (HA) meshes (HA/ES-ALA), a novel synergistic transdermal delivery nanogel, are developed for enhancing PDT of HS. HA/ES-ALA has a unique structure and property to protect unilaminar ES-ALA with HA meshes and actively target hypertrophic scar fibroblasts (HSFs) with HA receptors. Both in vitro and in vivo experiments demonstrate that HA/ES-ALA has a remarkable transdermal delivery ability with penetrating channels and a membrane-fusion mechanism. Meanwhile, the synergistic delivery mechanism is visually characterized as three stages: synergistic penetration, targeting aggregation and transmembrane delivery. With the synergistic effect, HA/ES-ALA can realize a targeted transdermal delivery, and significantly improve ALA utilization and enhance PDT efficacy. The results demonstrate an effective transdermal delivery route to enhance therapy for HS as well as other skin diseases.

In vivo and in vitro biocompatibility study of MnFe2O4 and Cr2Fe6O12 as photosensitizer for photodynamic therapy and drug delivery of anti-cancer drugs

In The present project, a variety of MnFe₂O₄ (Mn) and Cr₂Fe₆O₁₂ (Cr)-based nanocarriers (NCs) were synthesized as photosensitizer and NCs for delivery of chemotherapeutic curcumin (CUR) and provide a new structure for Photodynamic Therapy (PDT). For determining efficiency of NCs release study, MTT assay, lethal dose test and hemolysis assay were carried out. The release study showed the release of CUR from NCs was pH-dependent, but, every NCs had its own behavior for releasing the drug. The data acquired from the release study showed the CUR release from Mn can reach to over 90% at acidic media instead of 41% at neutral media. However, the CUR released from Cr were approximately equal as Cr had equal zeta potential at both media. Hemolysis activity and lethal dose test displayed the cytotoxicity of NCs was neglectable at both in vitro and in vivo study. Also, the results of anti-cancer activity assay (MTT assay) showed that both of Cr and Mn NCs are suitable systems for PDT. Therefore, the results demonstrated that Mn is suitable NCs for PDT and anticancer drugs delivery of therapeutic drugs.

Polydopamine Coated PB-MnO2 Nanoparticles as an Oxygen Generator Nanosystem for Imaging-Guided Single-NIR-Laser Triggered Synergistic Photodynamic/Photothermal Therapy

Exploring a combined phototherapeutic strategy to overcome the limitations of a single mode therapy and inducing high anticancer efficiency is highly promising for precision cancer nanomedicine. However, a single-wavelength laser activates dual photothermal/photodynamic therapy (PTT/PDT) treatment is still a formidable challenge. Herein, we strategically design and fabricate a multifunctional theranostic nanosystem based on chlorin e6-functionalized polydopamine (PDA) coated prussian blue/manganese dioxide nanoparticles (PB-MnO₂@PDA-Ce6 NPs). Interestingly, the obtained PB-MnO₂@PDA NPs not only offer an effective delivery system for Ce6 but also provide strong optical absorption in the near-infrared range, endowing high antitumor efficacy of PTT. More importantly, the as-prepared PB-MnO₂@PDA-Ce6 nanoagents exhibit an effective oxygen generation, superior reactive oxygen species (ROS), and outstanding photothermal conversion ability to greatly improve PTT and PDT treatments. As a result, both in vitro and in vivo treatments guided by MR imaging on liver cancer cells reveal the complete cell/tumor eradication under a single wavelength of 660 nm laser irradiation, implying the simultaneous synergistic PDT/PTT effects triggered by PB-MnO₂@PDA-Ce6 nanoplatform, which are much higher than individual treatment. Taken together, our phototherapeutic nanoagents exhibit an excellent therapeutic performance, which may act as a nanoplatform to find safe and clinically translatable routes to accelerate cancer therapeutics.

Nanoparticles in Gastrooncology

BACKGROUND

Gastrointestinal malignancies have the greatest incidence and cancer-associated death rates worldwide. Routine therapeutic modalities include surgery, chemotherapy and radiation but they often fail to reach the goal of cancer-free survival.

SUMMARY

In the light of this urgent medical need for the treatment of GI tumors, nanotech-nology-based approaches, i.e. nanomedicine, promise new therapeutic options. Using nanoparticles instead of classically designed drugs, targeting anticancer agents directly to the tumor site may revolutionize both diagnostic and therapeutic tools thereby facilitating the identification and elimination of malignant cells. Importantly, diagnostic insight and therapeutic effects can be achieved simultaneously through the same nanoparticle. Additionally, a nanoparticle may be loaded with more than one agent, thereby further increasing the value and power of the nanotechnology approach in oncologic therapeutic concepts. Although most insight into mechanisms of nanomedicine has been gained from in vitro and preclinical in vivo models, few clinical trials have been conducted, and nanomedicine-based concepts are already part of standard treatment algorithms. However, despite substantial progress it remains a challenge to design nanoparticles that feature all desirable characteristics at the same time.

KEY MESSAGES

This review seeks to provide substantial insight into the current status of nanomedicine-based approaches employed for diagnostic and/or therapeutic purposes in the field of gastrointestinal cancers by highlighting achievements and pointing out unresolved issues that need to be further addressed by future research attempts.

Stimuli-responsive nanocarriers for drug delivery, tumor imaging, therapy and theranostics

In recent years, much progress has been motivated in stimuli-responsive nanocarriers, which could response to the intrinsic physicochemical and pathological factors in diseased regions to increase the specificity of drug delivery. Currently, numerous nanocarriers have been engineered with physicochemical changes in responding to external stimuli, such as ultrasound, thermal, light and magnetic field, as well as internal stimuli, including pH, redox potential, hypoxia and enzyme, etc. Nanocarriers could respond to stimuli in tumor microenvironments or inside cancer cells for on-demanded drug delivery and accumulation, controlled drug release, activation of bioactive compounds, probes and targeting ligands, as well as size, charge and conformation conversion, etc., leading to sensing and signaling, overcoming multidrug resistance, accurate diagnosis and precision therapy. This review has summarized the general strategies of developing stimuli-responsive nanocarriers and recent advances, presented their applications in drug delivery, tumor imaging, therapy and theranostics, illustrated the progress of clinical translation and made prospects.

Magnetic Targeting of mTHPC To Improve the Selectivity and Efficiency of Photodynamic Therapy

Photodynamic therapy (PDT) is a promising recognized treatment for cancer. To date, PDT drugs are injected systemically, and the tumor area is irradiated to induce cell death. Current clinical protocols have several drawbacks, including limited accessibility to solid tumors and insufficient selectivity of drugs. Herein, we propose an alternative approach to improve PDT effectiveness by magnetic targeting of responsive carriers conjugated to the PDT drug. We coordinatively attached a meso-tetrahydroxyphenylchlorin (mTHPC) photosensitizer to Ce-doped-γ-Fe₂O₃ maghemite nanoparticles (MNPs). These MNPs are superparamagnetic and biocompatible, and the resulting mTHPC-MNPs nanocomposites are stable in aqueous suspensions. MDA-MB231 (human breast cancer) cells incubated with the mTHPC-MNPs showed high uptake and high death rates in cell population after PDT. The exposure to external magnetic forces during the incubation period directed the nanocomposites to selected sites enhancing drug accumulation that was double that of cells with no magnetic exposure. Next, breast cancer tumors were induced subcutaneously in mice and treated magnetically. In vivo results showed accelerated drug accumulation in tumors of mice injected with mTHPC-MNP nanocomposites, compared to the free drug. PDT irradiation led to a decrease in tumor size of both groups, whereas treatment with the focused magnetic nanocomposites led to significant tumor regression. Our results demonstrate a method to improve the current PDT treatments by applying magnetic forces to effectively direct the drug to cancerous tissue. This approach leads to a highly localized and effective PDT process, opening new directions for clinical PDT protocols.

Novel Oxygen-Deficient Zirconia (ZrO2-x) for Fluorescence/Photoacoustic Imaging-Guided Photothermal/Photodynamic Therapy for Cancer

Theranostic nanoplatforms that integrate therapy and diagnosis in a single composite have become increasingly attractive in the field of precise and efficient tumor treatment. Herein, a novel oxygen-deficient zirconia (ZrO_2-x) nanosystem based on the conjugation of thiol-polyethylene glycol-amine (SH-PEG-NH₂) and chlorin e6 (Ce6) was elaborately designed and established for efficacious photothermal/photodynamic therapy (PTT/PDT) and fluorescence/photoacoustic (FL/PA) bimodal imaging for the first time. The crystalline-disordered, PEGylated ZrO_2-x nanoparticles (ZP NPs) displayed strong optical absorption in the near-infrared (NIR) window and were featured with significant photothermal conversion capacity. The ZP NPs were further covalently conjugated with Ce6 to form ZrO_2-x@PEG/Ce6 (ZPC) NPs, which displayed a long circulatory half-life, efficient tumor accumulation, and outstanding FL/PA imaging performance. Moreover, the nanocomposites effectively generated cytotoxic intracellular reactive oxygen species (ROS) responsive to laser activation. Both cell studies and animal experiments explicitly demonstrated that ZPC NPs mediated remarkable tumor ablation with minimal systemic toxicity thanks to their tumor-specific PTT/PDT effect. Collectively, these findings may open up new avenues to broaden the application of oxygen-deficient ZrO_2-x nanostructures as high-performance photothermal agents in tumor theranostics through rational design and accurate control of their physiochemical properties.

Janus Nanobullets Combine Photodynamic Therapy and Magnetic Hyperthermia to Potentiate Synergetic Anti-Metastatic Immunotherapy

Photodynamic therapy (PDT) is clinically promising in destructing primary tumors but ineffective against distant metastases. This study reports the use of immunogenic nanoparticles mediated combination of PDT and magnetic hyperthermia to synergistically augment the anti-metastatic efficacy of immunotherapy. Janus nanobullets integrating chlorine e6 (Ce6) loaded, disulfide-bridged mesoporous organosilica bodies with magnetic heads (M-MONs@Ce6) are tailored for redox/pH-triggered photosensitizer release accompanying their matrix degradation. Cancer cell membrane cloaking enables favorable tumor-targeted accumulation and prolonged blood circulation time of M-MONs@Ce6. The combination of PDT and magnetic hyperthermia has a strong synergy anticancer activity and simultaneously elicits a sequence of immunogenic cell death, resulting in synergistically tumor-specific immune responses. When combined with anti-CTLA-4 antibody, the biomimetic and biodegradable nanoparticle enables the notable eradication of primary and deeply metastatic tumors with low systematic toxicity, thus potentially advancing the development of combined hyperthermia, PDT, and checkpoint blockade immunotherapy to combat cancer metastasis.

Effects of gold nanoprism-assisted human PD-L1 siRNA on both gene down-regulation and photothermal therapy on lung cancer

Gold nanoprisms (GNPs) have been broadly studied for the potential applications in both imaging and treatment on tumors due to their special characteristics. Herein we reported that a new nanoplatform GNPs@PSS/PDADMAC-siRNA (GNPs-siRNA) was designed and fabricated by sequentially coating the GNPs with poly (sodium 4-styrenesulfonate) (PSS) and poly (-diallyldimethylammonium chloride) (PDADMAC) to carry small interfering RNA (siRNA). Human program death-ligand 1 (PD-L1) was recently known to be crucial for cancer cell survival through the intrinsic signaling activities, besides serving as an important checkpoint gene in immune system. We successfully attached the human PD-L1 siRNA to the surface of GNPs@PSS/PDADMAC to obtain the GNPs-hPD-L1 siRNA nanoplatform. Real Time Cellular Analysis (RTCA) assay demonstrated that GNPs-hPD-L1 siRNA exhibited remarkable capacity to inhibit the proliferation of human lung cancer cells. Subsequent in vitro and in vivo experiments verified that the GNPs-hPD-L1 siRNA not only functioned as a carrier for siRNA delivery to down-regulate the hPD-L1 expression, but also served for photoacoustic (PA) imaging and photothermal agents for photothermal therapy (PTT) in both human lung cancer cells and human lung cancer cells-derived tumors. Our findings could be expected to provide an innovative direction for future clinical transformation application. STATEMENT OF SIGNIFICANCE: To our knowledge, this is the first paper related to the hPD-L1 siRNA delivery combined with the gold nanoparticles, especially the gold nanoprisms. The as-prepared GNPs-hPD-L1 siRNA nanoplatform not only functioned as a carrier for siRNA delivery to down-regulate the PD-L1 expression, but also acted as photothermal agents for theranostic effects in both human lung cancer cells and human lung cancer cells-derived tumors. The as-prepared GNPs-hPD-L1 siRNA nanoplatform could knock down human PD-L1 gene expression, which caused the inhibition on proliferation of human lung cancer cell in vitro or in vivo. The as-prepared GNPs-hPD-L1 siRNA nanoplatform possessed excellent photoacoustic imaging ability and photothermal therapy effects.

Optical-Based (Bio) Sensing Systems Using Magnetic Nanoparticles

In recent years, various reports related to sensing application research have suggested that combining the synergistic impacts of optical, electrical or magnetic properties in a single technique can lead to a new multitasking platform. Owing to their unique features of the magnetic moment, biocompatibility, ease of surface modification, chemical stability, high surface area, high mass transference, magnetic nanoparticles have found a wide range of applications in various fields, especially in sensing systems. The present review is comprehensive information about magnetic nanoparticles utilized in the optical sensing platform, broadly categorized into four types: surface plasmon resonance (SPR), surface-enhanced Raman spectroscopy (SERS), fluorescence spectroscopy and near-infrared spectroscopy and imaging (NIRS) that are commonly used in various (bio) analytical applications. The review also includes some conclusions on the state of the art in this field and future aspects.

Multimodal Composite Iron Oxide Nanoparticles for Biomedical Applications

Background

Iron oxide nanoparticles (IONPs) are excellent candidates for biomedical imaging because of unique characteristics like enhanced colloidal stability and excellent in vivo biocompatibility. Over the last decade, material scientists have developed IONPs with better imaging and enhanced optical absorbance properties by tuning their sizes, shape, phases, and surface characterizations. Since IONPs could be detected with magnetic resonance imaging, various attempts have been made to combine other imaging modalities, thereby creating a high-resolution imaging platform. Composite IONPs (CIONPs) comprising IONP cores with polymeric or inorganic coatings have recently been documented as a promising modality for therapeutic applications.

Methods

In this review, we provide an overview of the recent advances in CIONPs for multimodal imaging and focus on the therapeutic applications of CIONPs.

Result

CIONPs with phototherapeutics, IONP-based nanoparticles are used for theranostic application via imaging guided photothermal therapy.

Conclusion

CIONP-based nanoparticles are known for theranostic application, longstanding effects of composite NPs in in vivo systems should also be studied. Once such issues are fixed, multifunctional CIONP-based applications can be extended for theranostics of diverse medical diseases in the future.

O2-Cu/ZIF-8@Ce6/ZIF-8@F127 Composite as a Tumor Microenvironment-Responsive Nanoplatform with Enhanced Photo-/Chemodynamic Antitumor Efficacy

Hypoxia and overexpression of glutathione (GSH) are typical characteristics of the tumor microenvironment, which severely hinders cancer treatments. Here, we design a novel biodegradable therapeutic system, O₂-Cu/ZIF-8@Ce6/ZIF-8@F127 (OCZCF), to simultaneously achieve GSH depletion and O₂-enhanced combination therapy. Notably, the doped Cu²⁺ doubles the O₂ storage capacity of the ZIF-8 matrix, which makes OCZCF an excellent pH-sensitive O₂ reservoir for conquering tumor hypoxia, enhancing the photodynamic therapy (PDT) efficiency of chlorin e6 (Ce6) under 650 nm laser irradiation. Moreover, the released Cu²⁺ can act as a smart reactive oxygen species protector by consuming intracellular GSH. The byproduct Cu⁺ will undergo highly efficient Fenton-like reaction to achieve chemodynamic therapy (CDT) in the presence of abundant H₂O₂. The accompanying O₂ will further alleviate hypoxia. The in vitro and in vivo experimental data indicate that OCZCF could cause remarkable tumor inhibition through enhanced synergetic PDT and CDT, which may open up a new path for cancer therapy.