Synthesis of Hollow Biomineralized CaCO3-Polydopamine Nanoparticles for Multimodal Imaging-Guided Cancer Photodynamic Therapy with Reduced Skin Photosensitivity

Accelerated mapping of electronic density of states patterns of metallic nanoparticles via machine-learning

Within first-principles density functional theory (DFT) frameworks, it is challenging to predict the electronic structures of nanoparticles (NPs) accurately but fast. Herein, a machine-learning architecture is proposed to rapidly but reasonably predict electronic density of states (DOS) patterns of metallic NPs via a combination of principal component analysis (PCA) and the crystal graph convolutional neural network (CGCNN). With the PCA, a mathematically high-dimensional DOS image can be converted to a low-dimensional vector. The CGCNN plays a key role in reflecting the effects of local atomic structures on the DOS patterns of NPs with only a few of material features that are easily extracted from a periodic table. The PCA-CGCNN model is applicable for all pure and bimetallic NPs, in which a handful DOS training sets that are easily obtained with the typical DFT method are considered. The PCA-CGCNN model predicts the R2 value to be 0.85 or higher for Au pure NPs and 0.77 or higher for Au@Pt core@shell bimetallic NPs, respectively, in which the values are for the test sets. Although the PCA-CGCNN method showed a small loss of accuracy when compared with DFT calculations, the prediction time takes just ~ 160 s irrespective of the NP size in contrast to DFT method, for example, 13,000 times faster than the DFT method for Pt147. Our approach not only can be immediately applied to predict electronic structures of actual nanometer scaled NPs to be experimentally synthesized, but also be used to explore correlations between atomic structures and other spectrum image data of the materials (e.g., X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy).

Cancer-Cell-Activated in situ Synthesis of Mitochondria-Targeting AIE Photosensitizer for Precise Photodynamic Therapy

Maximization of phototoxic damage on tumor with minimized side effect on normal tissue is essential for effective anticancer photodynamic therapy (PDT). This requires highly cancer-cell-specific or even cancer-cell-organelle-specific synthesis or delivery of efficient photosensitizers (PSs) in vitro and in vivo, which is difficult to achieve. Herein, we report a strategy of cancer-cell-activated PS synthesis, by which an efficient mitochondria-targeting photosensitizer with aggregation-induced-emission (AIE) feature can be selectively synthesized as an efficient image-guided PDT agent inside cancer cells. MOF-199, a Cu^II -based metal-organic framework, was selected as an inert carrier to load the PS precursors for efficient delivery and served as a Cu^I catalyst source for in situ click reaction to form PSs exclusively in cancer cells. The in situ synthesized PS showed mitochondria-targeting capability, allowing potent cancer-cell-specific ablation under light irradiation. The high specificity of PSs produced in cancer cells also makes it safer post-treatment.

A size-tunable nanoplatform: enhanced MMP2-activated chemo-photodynamic immunotherapy based on biodegradable mesoporous silica nanoparticles

Although immunotherapy is emerging as a revolutionary strategy for cancer therapy, its clinical effect is severely impaired by adaptive immune evasion and inefficient activation of antitumor immune response. Photodynamic therapy and chemotherapy have been shown to efficiently enhance the therapeutic effect of PD-L1 immunotherapy via different mechanisms. However, the lack of a precise drug delivery system seriously impedes the clinical application of combination therapy. To address these restrictions, a matrix metalloproteinases-2 (MMP2)-activated shrinkable nanosystem was developed to potentiate the antitumor efficacy of anti-PD-L1 antibody (aPDL1) delivered along with a chemo-photodynamic therapy. The nanosystem maintains its structure to accelerate tumor accumulation and shrinks down to a smaller size to facilitate tumor penetration and cellular uptake upon arriving in the tumor microenvironment. The exposure of aPDL1 on the surface of the biodegradable mesoporous silica cores (bMSNs) blocks the PD-1/PD-L1 interaction between tumor cells and T cells. Meanwhile, photosensitizer chlorin e6 (Ce6) and paclitaxel (PTX) loaded bMSNs effectively enter tumor cells and induce chemo-photodynamic therapy. The nanosystem elicits a chemo-photodynamic-induced immune response and improves the therapeutic effect of PD-L1 blockade mediated by aPDL1. Furthermore, the nanosystem displays a sustained prohibitive effect on tumor metastasis to distant sites. Our work presents a promising strategy for enhancing the efficacy of cancer immunotherapy.

Biomineralized calcium carbonate nanohybrids for mild photothermal heating-enhanced gene therapy

It is of great significance to develop multifunctional gene carriers to achieve treatments with enhanced therapeutic effects in an inflammation-free manner. In this work, assembled micelles of polysaccharide were utilized for the biomineralization of calcium carbonate to produce one-dimensional Alg-CaCO₃ nanoparticles. In order to introduce both functions of mild hyperthermia and gene transfection, polydopamine (PDA) coating was applied to conjugate cationic polymers on the surface of nanoparticles. The resultant ACDP nanohybrids exhibited enhanced performance as gene carriers under near infrared (NIR) light irradiation at a low power density. Meanwhile, the pH-responsive degradation of gene carriers could further promote gene release for better effectiveness. The enhanced gene therapy induces tumor cell apoptosis, which could prevent inflammatory responses. The feasibility of mild hyperthermia-enhanced gene therapy for tumor treatment was investigated in vitro and in vivo. In addition, dual-modal ultrasound (US) and photoacoustic (PA) imaging was also realized to monitor and guide the treatment processes. The current work provides a new avenue for the construction of multifunctional platform to realize cancer therapy with improved therapeutic effectiveness in an inflammation-free manner.

Exploiting a New Approach to Destroy the Barrier of Tumor Microenvironment: Nano-Architecture Delivery Systems

Recent findings suggest that tumor microenvironment (TME) plays an important regulatory role in the occurrence, proliferation, and metastasis of tumors. Different from normal tissue, the condition around tumor significantly altered, including immune infiltration, compact extracellular matrix, new vasculatures, abundant enzyme, acidic pH value, and hypoxia. Increasingly, researchers focused on targeting TME to prevent tumor development and metastasis. With the development of nanotechnology and the deep research on the tumor environment, stimulation-responsive intelligent nanostructures designed based on TME have attracted much attention in the anti-tumor drug delivery system. TME-targeted nano therapeutics can regulate the distribution of drugs in the body, specifically increase the concentration of drugs in the tumor site, so as to enhance the efficacy and reduce adverse reactions, can utilize particular conditions of TME to improve the effect of tumor therapy. This paper summarizes the major components and characteristics of TME, discusses the principles and strategies of relevant nano-architectures targeting TME for the treatment and diagnosis systematically.

Biodegradable MnFe-hydroxide nanocapsules to enable multi-therapeutics delivery and hypoxia-modulated tumor treatment

Developing drug delivery platforms that can modulate a tumor microenvironment and deliver multiple therapeutics to targeted tumors is critical for efficient cancer treatment. Achieving these platforms still remains a great challenge. Herein, biodegradable nanocapsules based on MnFe hydroxides (H-MnFe(OH)x) have been developed as a new type of cargo delivery with high loading capacity and catalytic activity, enabling synergetic therapy with promoted efficacy by relieving hypoxia in tumor tissues. As a proof of concept, a photosensitizer (indocyanine green, ICG) and a chemotherapeutic drug (doxorubicin, DOX) are co-loaded in nanocapsules and selectively released upon degradation of the nanocapsules in the acidic tumor microenvironment, and are promoted by near infrared irradiation. Meanwhile, Mn2+/Fe3+ ions released from the degradation of nanocapsules catalyze the conversion of H2O2 in a tumor microenvironment into oxygen, which modulates tumor hypoxia and dramatically boosts multimodal therapies. Remarkable synergistic anticancer outcomes have been demonstrated both in vitro and in vivo, paving the way towards future multifunctional therapeutic platforms.

Synthetic infrared nano-photosensitizers with hierarchical zoom-in target-delivery functionalities for precision photodynamic therapy

Surgical assailment at the vulnerable subcellular organelles (e.g. mitochondria) by photodynamic therapy (PDT) is perceived as the most devastating approach to eradicate the tumors. Herein, we programmed a novel near-infrared (NIR) PDT construct illustrating appreciable hierarchical zoom-in targeting scenario, namely, primary cell-level targeting to carcinoma post systemic dosage and subcellular level targeting to mitochondria. Pertaining to tumor-targeting function, charge reversal chemistry selectively responsive to acidic tumoral microenvironments (pH 6.8) was implemented as the external corona of PDT constructs. This charge transformative exterior entitled minimal biointerfacial reactions in systemic retention but intimate affinities to cytomembranes selectively in tumoral microenvironments, thereby resulting in preferential uptake by tumors. Furthermore, the proposed PDT constructs were equipped with mitochondria targeting triphenylphosphonium (TPP) motif, which appeared to propel intriguing 88% colocalization with mitochondria. Therefore, overwhelming cytotoxic potencies were accomplished by our carefully engineered photodynamic constructs. Another noteworthy is the photodynamic constructs characterized to be excited at tissue-penetrating NIR (980 nm) based on energy transfer between their internal components of anti-Stoke upconversion nanoparticles (UCN, donor) and photodynamic chlorin e6 (Ce6, acceptor). Therefore, practical applications for photodynamic treatment of intractable solid carcinoma were greatly facilitated and complete tumor eradication was achieved by systemic administration of the ultimate multifunctional NIR photodynamic constructs.

Organic Nanoparticles with Persistent Luminescence for In Vivo Afterglow Imaging-Guided Photodynamic Therapy

Optical imaging-guided photodynamic therapy (PDT), with precise localization and non-invasive treatment of tumors, is an emerging technique with great potential for cancer therapy. However, impaired by tissue auto-fluorescence that causes low signal-to-background ratio (SBR), most fluorescence imaging systems show poor sensitivity to tumors in vivo. In this study, we synthesized organic nanoparticles (ONPs) with persistent luminescence and good biocompatibility for afterglow imaging-guided PDT. The ONPs displayed near-infrared light emission with half-life time at minute level, which offered high SBR and good tissue penetration for in vivo afterglow tumor imaging. Taking advantage of their abundant singlet oxygen generation by NIR laser irradiation guided to the tumor sites, the ONPs also enabled imaging-guided PDT for efficient suppression of tumor growth in mice with minimal damage to major organs.

Activable Multi-Modal Nanoprobes for Imaging Diagnosis and Therapy of Tumors

Malignant tumors have become one of the major causes of human death, but there remains a lack of effective methods for tiny tumor diagnosis, metastasis warning, clinical efficacy prediction, and effective treatment. In this context, localizing tiny tumors via imaging and non-invasively extracting molecular information related to tumor proliferation, invasion, metastasis, and drug resistance from the tumor microenvironment have become the most fundamental tasks faced by cancer researchers. Tumor-associated microenvironmental physiological parameters, such as hypoxia, acidic extracellular pH, protease, reducing conditions, and so forth, have much to do with prognostic indicators for cancer progression, and impact therapeutic administrations. By combining with various novel nanoparticle-based activatable probes, molecular imaging technologies can provide a feasible approach to visualize tumor-associated microenvironment parameters noninvasively and realize accurate treatment of tumors. This review focuses on the recent achievements in the design of “smart” nanomedicine responding to the tumor microenvironment-related features and highlights state-of- the-art technology in tumor imaging diagnosis and therapy.

Phenolic-enabled nanotechnology: versatile particle engineering for biomedicine

Phenolics are ubiquitous in nature and have gained immense research attention because of their unique physiochemical properties and widespread industrial use. In recent decades, their accessibility, versatile reactivity, and relative biocompatibility have catalysed research in phenolic-enabled nanotechnology (PEN) particularly for biomedical applications which have been a major benefactor of this emergence, as largely demonstrated by polydopamine and polyphenols. Therefore, it is imperative to overveiw the fundamental mechanisms and synthetic strategies of PEN for state-of-the-art biomedical applications and provide a timely and comprehensive summary. In this review, we will focus on the principles and strategies involved in PEN and summarize the use of the PEN synthetic toolkit for particle engineering and the bottom-up synthesis of nanohybrid materials. Specifically, we will discuss the attractive forces between phenolics and complementary structural motifs in confined particle systems to synthesize high-quality products with controllable size, shape, composition, as well as surface chemistry and function. Additionally, phenolic's numerous applications in biosensing, bioimaging, and disease treatment will be highlighted. This review aims to provide guidelines for new scientists in the field and serve as an up-to-date compilation of what has been achieved in this area, while offering expert perspectives on PEN's use in translational research.

Organic/inorganic nanohybrids rejuvenate photodynamic cancer therapy

The development of nanotechnology has changed the 100-year-old paradigm of photodynamic therapy (PDT), in which organic/inorganic hybrid nanomaterials have made great contributions. In this review, we first describe the mechanisms of PDT and discuss the limitations of conventional PDT. On this basis, we summarize recent progress in organic/inorganic nanohybrids-based photodynamic agents, highlighting how these nanohybrids can be programmed to overcome challenges in photodynamic cancer therapy.

Tumor microenvironment-activated NIR-II reagents for tumor imaging and therapy

Second near-infrared window (NIR-II, 1000-1700 nm) absorption and fluorescent agents have attracted great attention because they can overcome the penetration limitation of the first near-infrared window (NIR-I, 750-1000 nm). However, these always "on" agents face the severe problem of being susceptible to retention and phagocytosis by the reticuloendothelial system after intravenous administration, which results in signal interference during diagnosis and side effects during treatment. Accordingly, tumor microenvironment-responsive smart agents (smart NIR-II agents), whose imaging and therapeutic functions can only be triggered in tumors, can overcome this limitation. Thus, NIR-II smart agents, which exhibit a combined response to the tumor microenvironment and NIR-II, make full use of the advantages of both triggers and improve the precision diagnosis and effective treatment of cancer. This review summarizes the recent advances in tumor microenvironment-activated NIR-II agents for tumor diagnosis and treatment, including smart NIR-II fluorescence imaging, photoacoustic imaging, photothermal therapy and photodynamic therapy. Finally, the challenges and perspectives of NIR-II smart agents for tumor diagnosis and treatment are proposed.

Single-chain antibody-decorated Au nanocages@liposomal layer nanoprobes for targeted SERS imaging and remote-controlled photothermal therapy of melanoma cancer cells

The development of theranostic platforms combining surface-enhanced Raman spectroscopy (SERS) imaging with NIR-stimulated photothermal therapy (PTT) is of utmost importance for the precise diagnosis and selective treatment of cancers, especially in superficial solid tumors. For this purpose, a versatile theranostic nanoprobe of liposomal layer-coated Au nanocages (AuNCs) was decorated with an anti-MUC18 single-chain antibody (scFv). 4-mercapto benzoic acid (p-MBA)-labeled AuNCs (p-AuNCs) were coated by a liposomal layer (p-AuNCs@lip), followed by conjugating anti-MUC18 scFv via post-insertion method to form immuno-liposomal layer-coated AuNCs (p-AuNCs@scFv-lip). Physicochemical characterizations of the p-AuNCs@scFv-lip were investigated by transmission electron microscopy (TEM) and UV-vis and Raman spectroscopy. Furthermore, the targeting ability and theranostic efficiency of the nanoprobe were evaluated for specific diagnosis and treatment of cancerous melanoma cells by flow cytometry, SERS mapping, and live/dead assay. The formation of lipid layer on p-AuNCs surface was confirmed by TEM imaging. After decorating the liposomal layer with scFv, a relevant red shift was observed in the UV-vis spectrum. Moreover, p-AuNCs@lip presented characteristic peaks in the Raman spectrum, which exhibited only a minor change after scFv conjugation (p-AuNCs@scFv-lip). Interestingly, the cellular uptake of AuNCs@scFv-lip by A375 cell line (MUC18⁺) showed a 24-fold enhancement compared with SKBR3 cells (MUC18^-). AuNCs@scFv-lip specifically identified A375 cells from SKBR cells via SERS mapping and effectively killed A375 cells through the PTT mechanism. Taken together, this theranostic platform can provide a promising tool for both in situ diagnosis and remote-controlled thermal ablation of cancer cells.

Immunomodulatory biomaterials and their application in therapies for chronic inflammation-related diseases

The degree of tissue injuries such as the level of scarring or organ dysfunction, and the immune response against them primarily determine the outcome and speed of healing process. The successful regeneration of functional tissues requires proper modulation of inflammation-producing immune cells and bioactive factors existing in the damaged microenvironment. In the tissue repair and regeneration processes, different types of biomaterials are implanted either alone or by combined with other bioactive factors, which will interact with the immune systems including immune cells, cytokines and chemokines etc. to achieve different results highly depending on this interplay. In this review article, the influences of different types of biomaterials such as nanoparticles, hydrogels and scaffolds on the immune cells and the modification of immune-responsive factors such as reactive oxygen species (ROS), cytokines, chemokines, enzymes, and metalloproteinases in tissue microenvironment are summarized. In addition, the recent advances of immune-responsive biomaterials in therapy of inflammation-associated diseases such as myocardial infarction, spinal cord injury, osteoarthritis, inflammatory bowel disease and diabetic ulcer are discussed.

Dual-Channel Theranostic System for Quantitative Self-Indication and Low-Temperature Synergistic Therapy of Cancer

A conventional theranostic system usually employs a single fluorescence channel to show the pharmacokinetic events, which usually fails to quantitatively reveal the true cumulative drug release and with low accuracy. Herein, indocyanine green (ICG) and chlorins e6 (Ce6) are selected not only as conventional photothermal/photodynamic agents, but also to offer two independent fluorescence channels to cross validate the authenticity of pharmacokinetic events and to quantitatively reveal cumulative drug release in tumor tissues in a "turn on" manner. Employing the Ca²⁺ of amorphous calcium carbonate as a reversible linker, the photosensitivity and fluorescence of Ce6 are physically quenched by ICG during circulation to reduce the side effect of photodynamic therapy (PDT) while being readily restored in tumor tissue to reveal the quantitative drug release. Most importantly, the combination of photothermal therapy (PTT) and PDT allows low-temperature synergistic therapy of cancer through the controlled expression of heat shock protein in cells and mild hyperthermia enhanced reactive oxygen species diffusion/penetration among cells. This work not only develops a facile approach to fabricate a dual-channel theranostic system to precisely indicate the accumulation and quantitative drug release in tumor tissue, but also presents a unique low-temperature synergistic strategy to destroy tumor in an effective and minimally invasive manner.

Internally Responsive Nanomaterials for Activatable Multimodal Imaging of Cancer

Advances in technology and nanomedicine have led to the development of nanoparticles that can be activated for multimodal imaging of cancer, where a stimulus induces a material modification that enhances image contrast. Multimodal imaging using nanomaterials with this capability can combine the advantages and overcome the limitations of any single imaging modality. When designed with stimuli-responsive abilities, the target-to-background ratio of multimodal imaging nanoprobes increases because specific stimuli in the tumor enhance the signal. Several aspects of the tumor microenvironment can be exploited as an internal stimulus response for multimodal imaging applications, such as the pH gradient, redox processes, overproduction of various enzymes, or combinations of these. In this review, design strategies are discussed and an overview of the recent developments of internally responsive multimodal nanomaterials is provided. Properly implementing this approach improves noninvasive cancer diagnosis and staging as well as provides a method to monitor drug delivery and treatment response.

Novel nanomaterial-organism hybrids with biomedical potential

Instinctive hierarchically biomineralized structures of various organisms, such as eggs, algae, and magnetotactic bacteria, afford extra protection and distinct performance, which endow fragile organisms with a tenacious ability to adapt and survive. However, spontaneous formation of hybrid materials is difficult for most organisms in nature. Rapid development of chemistry and materials science successfully obtained the combinations of organisms with nanomaterials by biomimetic mineralization thus demonstrating the reproduction of the structures and functions and generation of novel functions that organisms do not possess. The rational design of biomaterial-organism hybridization can control biological recognition, interactions, and metabolism of the organisms. Thus, nanomaterial-organism hybrids represent a next generation of organism engineering with great potential biomedical applications. This review summarizes recent advances in material-directed organism engineering and is mainly focused on biomimetic mineralization technologies and their outstanding biomedical applications. Three representative types of biomimetic mineralization are systematically introduced, including external mineralization, internal mineralization, and genetic engineering mineralization. The methods involving hybridization of nanomaterials and organisms based on biomimetic mineralization strategies are described. These strategies resulted in applications of various nanomaterial-organism hybrids with multiplex functions in cell engineering, cancer treatment, and vaccine improvement. Unlike classical biological approaches, this material-based bioregulation is universal, effective, and inexpensive. In particular, instead of traditional medical solutions, the integration of nanomaterials and organisms may exploit novel strategies to solve current biomedical problems. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Integrating Near-Infrared Visual Fluorescence with a Photoelectrochemical Sensing System for Dual Readout Detection of Biomolecules

Compared with traditional visible light-driven fluorescence visualization (FV), near-infrared (NIR)-induced FV is an interesting and promising method, while photoelectrochemical (PEC) immunoassay sensing possesses the advantages of high sensitivity, low cost, and simple instrumentation. We combined PEC sensing with NIR-induced FV together and developed a dual readout sensing platform. In this protocol, based on the antibody-analyte (i.e., antigen, DNA, and RNA) reaction and the sandwich-type structure, CuInS₂ microflowers as the matrix provided the original background photocurrent; chlorin e6 (Ce6) was conjugated to antibody-modified upconversion nanoparticles and formed a signal label for the PEC sensing and naked-eye readout. Different from traditional PEC immunosensors, under NIR illumination, the developed dual mode sensing platform could achieve quick qualitative analysis and quantitative analysis. Preliminary application performance of the proposed biosensor in prostate-specific antigen analysis is acceptable, indicating its promising potential in clinical/biological studies.

A review of advanced nanoformulations in phototherapy for cancer therapeutics

Phototherapy has the potential to play a greater role in oncology. Phototherapy converts light energy into either chemical energy or thermal energy, which eventually destroys cancer cells after a series of biological reactions. With nanotechnology applications in cancer therapeutics, it has become possible to prepare smart drug carriers with multifunctional properties at the nanoscale level. These nanocarriers may be able to deliver the drug molecules to the target site more efficiently in the form of nanoparticles. Several intrinsic and extrinsic properties of these nanocarriers help target the tumor cells exclusively, and by utilizing these features, drug molecules can be delivered to the tumor cells specifically, which results in high tumor uptake and better therapeutic effects ultimately. Nanocarriers can also be designed to carry different drugs together to provide a platform for combination therapy like chemo-photodynamic therapy and chemo-photodynamic-photothermal therapy. In combination therapy, co-delivery of all different drugs is crucial to obtain their synergistic effects, and with the help of nanocarriers, it is possible to co-deliver these drugs by loading them together onto the nanocarriers.

Sequential Modulations of Tumor Vasculature and Stromal Barriers Augment the Active Targeting Efficacy of Antibody-Modified Nanophotosensitizer in Desmoplastic Ovarian Carcinoma

Active-targeted nanoparticles are attractive carriers due to their potentials to facilitate specific delivery of drugs into tumor cells while sparing normal cells. However, the therapeutic outcomes of active-targeted nanomedicines are hampered by the multiple physiological barriers in the tumor microenvironment (TME). Herein, an epidermal growth factor receptor-targeted ultra-pH-sensitive nanophotosensitizer is fabricated, and the regulation of the TME to augment the active targeting ability and therapeutic efficacy is pinpointed. The results reveal that tumor vasculature normalization with thalidomide indiscriminately enhance the tumor accumulation of passive and active targeted nanoparticles, both of which are sequestered in the stromal bed of tumor mass. Whereas, photoablation of stromal cells located in perivascular regions significantly improves the accessibility of antibody-modified nanophotosensitizer to receptor-overexpressed cancer cells. After sequential regulation of TME, the antitumor efficacy of antibody-modified nanophotosensitizer is drastically enhanced through synergistic enhancements of tumor accumulation and cancer cell accessibility of active-targeted nanoparticles. The study offers deep insights about the intratumoral barriers that hinder the active-targeted nanoparticles delivery, and provides a basis for developing more effective strategies to accelerate the clinical translation of active-targeted nanomedicines.

Reactive Oxygen Species-Regulating Strategies Based on Nanomaterials for Disease Treatment

Reactive oxygen species (ROS) play an essential role in physiological and pathological processes. Studies on the regulation of ROS for disease treatments have caused wide concern, mainly involving the topics in ROS-regulating therapy such as antioxidant therapy triggered by ROS scavengers and ROS-induced toxic therapy mediated by ROS-elevation agents. Benefiting from the remarkable advances of nanotechnology, a large number of nanomaterials with the ROS-regulating ability are developed to seek new and effective ROS-related nanotherapeutic modalities or nanomedicines. Although considerable achievements have been made in ROS-based nanomedicines for disease treatments, some fundamental but key questions such as the rational design principle for ROS-related nanomaterials are held in low regard. Here, the design principle can serve as the initial framework for scientists and technicians to design and optimize the ROS-regulating nanomedicines, thereby minimizing the gap of nanomedicines for biomedical application during the design stage. Herein, an overview of the current progress of ROS-associated nanomedicines in disease treatments is summarized. And then, by particularly addressing these known strategies in ROS-associated therapy, several fundamental and key principles for the design of ROS-associated nanomedicines are presented. Finally, future perspectives are also discussed in depth for the development of ROS-associated nanomedicines.

A phthalocyanine-based self-assembled nanophotosensitizer for efficient in vivo photodynamic anticancer therapy

To develop highly efficient photosensitizers for photodynamic therapy, herein a zinc(II) phthalocyanine-folate conjugate (PcN-FA) used to construct an activatable nanophotosensitizer (NanoPcN-FA) through a facile self-assembly. The self-assembled nanophotosensitizer (NanoPcN) without folate-modification was used as a negative control. After self-assembly, the photoactivities of NanoPcN-FA was quenched. The in vitro studies showed that NanoPcN-FA could be taken in by folate-receptor (FR)-positive SKOV3 cells and activated in the cells. It also exhibited slightly higher photocytotoxicity against SKOV3 cells than NanoPcN. Moreover, the competitive assay confirmed that the cellular uptake of NanoPcN-FA was through a FR-mediated process. Finally, the in vivo results indicated that NanoPcN-FA could target tumor tissue of S180 rat ascitic tumor-bearing mice due to the folic acid (FA) ligand, leading to a highly efficient antitumor photodynamic efficacy with the tumor inhibition rate of 95%.

Recent Advances in a Polydopamine-Mediated Antimicrobial Adhesion System

The drug resistance developed by bacteria during antibiotic treatment has been a call to action for researchers and scientists across the globe, as bacteria and fungi develop ever increasing resistance to current drugs. Innovative antimicrobial/antibacterial materials and coatings to combat such infections have become a priority, as many infections are caused by indwelling implants (e.g., catheters) as well as improving postsurgical function and outcomes. Pathogenic microorganisms that can exist either in planktonic form or as biofilms in water-carrying pipelines are one of the sources responsible for causing water-borne infections. To combat this, researchers have developed nanotextured surfaces with bactericidal properties mirroring the topographical features of some natural antibacterial materials. Protein-based adhesives, secreted by marine mussels, contain a catecholic amino acid, 3,4-dihydroxyphenylalanine (DOPA), which, in the presence of lysine amino acid, empowers with the ability to anchor them to various surfaces in both wet and saline habitats. Inspired by these features, a novel coating material derived from a catechol derivative, dopamine, known as polydopamine (PDA), has been designed and developed with the ability to adhere to almost all kinds of substrates. Looking at the immense potential of PDA, this review article offers an overview of the recent growth in the field of PDA and its derivatives, especially focusing the promising applications as antibacterial nanocoatings and discussing various antimicrobial mechanisms including reactive oxygen species-mediated antimicrobial properties.

Design and application of inorganic nanoparticles for sonodynamic cancer therapy

This review focus on the recent developments in inorganic nanomaterials for tumor SDT.

Generality of liquid precursor phases in gas diffusion-based calcium carbonate synthesis

We confirm the presence of liquid calcium carbonate precursor species in absence of additives in gas diffusion systems.

The preparation, structure and luminescent properties of Mg–CaCO3:Eu3+ phosphors

Morphology and luminescence properties of Mg–CaCO₃:Eu³⁺ phosphors are found to change with the initial magnesium ion concentration.

Stimuli-responsive polydopamine-based smart materials

This review provides in-depth insight into the structural engineering of PDA-based materials to enhance their responsive feature and the use of them in construction of PDA-based stimuli-responsive smart materials.

Rational design of iridium–porphyrin conjugates for novel synergistic photodynamic and photothermal therapy anticancer agents

Iridium–porphyrin conjugates assembled in nanoparticles are photosensitizers that exhibit excellent photothermal imaging and synergistic PDT and PTT in vivo.

Stimulus-responsive nanocarriers for targeted drug delivery

Cancer is a multifactorial disease that involves unique tumor microenvironment (TEM) and abnormal organs with complex structures.

Highly Penetrable and On-Demand Oxygen Release with Tumor Activity Composite Nanosystem for Photothermal/Photodynamic Synergetic Therapy

A deep penetrating and pH-responsive composite nanosystem was strategically developed to improve the efficacy of synergetic photothermal/photodynamic therapy (PTT/PDT) against hypoxic tumor. The designed nanosystem ([PHC]PP@HA NPs) was constructed by coloading hemoglobin (Hb) and chlorin e6 on polydopamine to build small-sized PHC NPs, which were encapsulated inside the polymer micelles (poly(ethylene glycol)-poly(ethylenimine)) and then capped with functionalized hyaluronic acid. The pH-responsive feature made [PHC]PP@HA NPs retain an initial size of ∼140 nm in blood circulation but rapidly release small PHC NPs (∼10 nm) with a high tumor-penetrating ability in the tumor microenvironment. The in vitro penetration experiment showed that the penetration depth of PHC NPs in the multicellular tumor spheroids exceeded 110 μm. The [PHC]PP@HA NPs exhibited excellent biocompatibility, deep tumor permeability, high photothermal conversion efficiency (47.09%), and low combination index (0.59) under hypoxic conditions. Notably, the nanosystem can freely adjust the release of oxygen and damaging PHC NPs in an on-demand manner on the basis of the feedback of tumor activity. This feedback tumor therapy significantly improved the synergistic effect of PTT/PDT and reduced its toxic side effects. The in vivo antitumor results showed that the tumor inhibition rate of [PHC]PP@HA NPs with an on-demand oxygen supply of Hb was ∼100%, which was much better than those of PTT alone and Hb-free nanoparticles ([PC]PP@HA NPs). Consequently, the [PHC]PP@HA NP-mediated PTT/PDT guided by feedback tumor therapy achieved an efficient tumor ablation with an extremely low tumor recurrence rate (8.3%) 60 d later, indicating the versatile potential of PTT/PDT.

Polydopamine-Based Multifunctional Antitumor Nanoagent for Phototherapy and Photodiagnosis by Regulating Redox Balance

The development of multifunctional nanoagents for the simultaneous achievement of high diagnostic and therapeutic performances is significant for precise cancer treatment. Herein, we report on a polydopamine (PDA)-based multifunctional nanoagent, PML, in which the methylene blue (MB) photosensitizer (PS) and l-arginine (l-Arg) tumor-targeting species are equipped. After selectively accumulating in tumor sites, glutathione (GSH)-responsive PML degradation can controllably release loaded MB to produce singlet oxygen (¹O₂) under near-infrared (NIR) photoirradiation. This GSH-depleted PS release process can not only weaken the body's antioxidant defence ability but also synergistically increase the ¹O₂ concentration. Therefore, GSH depletion-enhanced photodynamic therapy (PDT) efficiency is logically achieved by regulating the intracellular redox balance. In addition, our nanoagent can guide photoacoustic/NIR thermal dual-modal imaging and convert light into heat for cooperative cancer phototherapy because of the inherent photothermal conversion nature of PDA. As a result, excellent in vivo antitumor phototherapy (PDT + PTT) is achieved under the precise guidance of dual-modal imaging. This work not only realizes the integration of cancer diagnosis and treatment through PDA-based nanocarriers but also delivers dimensions in designing the next generation of multifunctional antitumor nanoagents for enhanced phototherapy and photodiagnosis by regulating the redox balance.

Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes

The use of fluorescent probes in a multitude of applications is still an expanding field. This review covers the recent progress made in small molecular, spirocyclic xanthene-based probes containing different heteroatoms (e.g., oxygen, silicon, carbon) in position 10'. After a short introduction, we will focus on applications like the interaction of probes with enzymes and targeted labeling of organelles and proteins, detection of small molecules, as well as their use in therapeutics or diagnostics and super-resolution microscopy. Furthermore, the last part will summarize recent advances in the synthesis and understanding of their structure-behavior relationship including novel computational approaches.

Biomineralization at fluid interfaces

Biomineralization is of paramount importance for life on Earth. The delicate balance of physicochemical interactions at the interface between organic and inorganic matter during all stages of biomineralization resembles an extremely high complexity. The coordination of this sophisticated biological machinery and physicochemical scenarios is certainly a wonderful show of nature. Understanding of the biomineralization processes is still far from complete. The recent advances in biomineralization research from the Colloid and Interface Science perspective are reviewed herein. The synergy between this two fields of research is demonstrated. The unique opportunities offered by purposefully designed fluid interfaces, mainly Langmuir monolayers are presented. Biomedical applications of biomineral-based nanostructures are discussed, showing their improved biocompatibility and on-demand delivery features. A brief guide to the array of state-of-the-art experimental techniques for unraveling the mechanisms of biomineralization using fluid interfaces is included. In summary, the fruitful and exciting crossroad between Colloid and Interface Science with Biomineralization is exhibited.

Smart responsive-calcium carbonate nanoparticles for dual-model cancer imaging and treatment

Contrast-enhanced ultrasound (CEUS) is widely applied in cancer diagnosis clinically. However, the gas-filled contrast agents are unstable in the blood and exhibit shorter imaging time, which limit their clinical use. In this study, a diagnostic nanoparticle system was developed for dual-mode imaging (ultrasound and fluorescence), which after encapsulation with doxorubicin (DOX) demonstrated simultaneous therapeutic function towards cancer treatment. Thus, calcium carbonate (CaCO₃) nanoparticles were encapsulated with doxorubicin (DOX) to obtain CaCO₃-DOX. Under acidic conditions, it produced carbon dioxide (CO₂) to enhance ultrasound imaging and increase the release of DOX. After intravenously injecting CaCO₃-DOX to tumor-bearing mice, in the presence of an ultrasound field, CO₂bubbles were sufficiently generated at the tumor tissues for echogenic reflectivity. Also, the indocyanine green (ICG) was encapsulated into CaCO₃ nanoparticles, to further detect the tumor with fluorescence. The resultant theranostic nanoparticle system exhibited therapeutic efficacy towards tumour-bearing mice. Overall, this investigation provides an attractive strategy for dual-mode cancer diagnostics.

Cell-tailored calcium carbonate particles with different crystal forms from nanoparticle to nano/microsphere

Inspired by biomineralization, the first synthesis of size-tunable calcium carbonates from nanoparticles (YC-CaCO₃ NPs) to nano/microspheres (YC-CaCO₃ N/MSs) with a porous structure was accomplished using a facile method under the mediation of the secretion from yeast cells (YCs). The biomolecules derived from the secretion of YCs were used as conditioning and stabilizing agents to control the biosynthesis of the YC-CaCO₃ materials. The morphology and crystal forms of YC-CaCO₃ materials can be affected by the biomolecules from the secretion of YCs. With increasing concentrations of biomolecules, the morphologies of the obtained CaCO₃ materials changed from nanoparticles to nano/microspheres with a porous structure, while the crystal forms transformed from amorphous to calcite. Functional investigations showed that YC-CaCO₃ NSs with a porous structure effectively acted as anticancer drug carriers with accurate and selective drug release in tumor tissue, which suggests that they have great potential to function as a therapeutic delivery system. These application features are mainly attributed to the satisfactory biocompatibility and biodegradability, high drug-loading capacity, and pH-dependent sustained drug release performance of the porous YC-CaCO₃ NSs. The biomimetic synthesis strategy of YC-CaCO₃ materials mediated by YC secretion not only helps to shed light on the biomineralization mechanism in organisms, but may also lead to a new means of biosynthesizing organic–inorganic nanocomposites.

The synthesis of cell-tailored calcium carbonate with different crystal forms can be controlled from nanoparticle to nano/microsphere by a bio-inspired strategy.

CaCO3-Assisted Preparation of pH-Responsive Immune-Modulating Nanoparticles for Augmented Chemo-Immunotherapy

Due to the negative roles of tumor microenvironment (TME) in compromising therapeutic responses of various cancer therapies, it is expected that modulation of TME may be able to enhance the therapeutic responses during cancer treatment. Herein, we develop a concise strategy to prepare pH-responsive nanoparticles via the CaCO₃-assisted double emulsion method, thereby enabling effective co-encapsulation of both doxorubicin (DOX), an immunogenic cell death (ICD) inducer, and alkylated NLG919 (aNLG919), an inhibitor of indoleamine 2,3-dioxygenase 1 (IDO1). The obtained DOX/aNLG919-loaded CaCO₃ nanoparticles (DNCaNPs) are able to cause effective ICD of cancer cells and at the same time restrict the production of immunosuppressive kynurenine by inhibiting IDO1. Upon intravenous injection, such DNCaNPs show efficient tumor accumulation, improved tumor penetration of therapeutics and neutralization of acidic TME. As a result, those DNCaNPs can elicit effective anti-tumor immune responses featured in increased density of tumor-infiltrating CD8⁺ cytotoxic T cells as well as depletion of immunosuppressive regulatory T cells (Tregs), thus effectively suppressing the growth of subcutaneous CT26 and orthotopic 4T1 tumors on the Balb/c mice through combined chemotherapy & immunotherapy. This study presents a compendious strategy for construction of pH-responsive nanoparticles, endowing significantly enhanced chemo-immunotherapy of cancer by overcoming the immunosuppressive TME.

Modulation of immune responses with nanoparticles and reduction of their immunotoxicity

Particles with a size range of 1-100 nm used in various fields of life sciences are called nanoparticles (NPs). Currently, nanotechnology has a wide range of applications in biomedical research, industries and in almost all types of modern technology. The growing applications of nanotechnology in medicine urge scientists to analyze the impact of NPs on human body tissues and the immune system. Easy surface modifications of the NPs enable the modulation of the immune system either by evading the immune system to prevent allergic reactions or by enhancing the immunogenic response. In this review, we discussed the various possible theories and practical implications reported to date for the applications of nanotechnology in immunostimulation and immunosuppression for favorable immune response, such as vaccine delivery and cancer treatments. In the last part of this paper, we also discussed the biocompatibility and unfavorable immunotoxicity of NPs and methods for lowering their toxicity.

Highly photostable croconium dye-anchored cell membrane vesicle for tumor pH-responsive duplex imaging-guided photothermal therapy

The development of tumor acidic microenvironment-responsive theranostic agents is a research hotspot. Herein, we developed highly photostable amphiphilic croconium dye-anchored red blood cell membrane vesicle (denoted as LET-5) for tumor pH-responsive near-infrared fluorescence (NIRF) and photoacoustic (PA) duplex imaging-guided photothermal therapy. In tumor acidic microenvironment, both NIRF and PA signals of LET-5 were significantly enhanced and the photothermal effect of LET-5 was activated. Notably, cell membrane-based vesicle with enhanced stability and long blood circulation significantly improved the tumor accumulation of croconium dye, thus achieving better therapeutic effect than free croconium dye. These findings provide a promising approach to construct amphiphilic dye-anchored cell membrane vesicle for cancer theranostics.

Stimuli-responsive and cellular targeted nanoplatforms for multimodal therapy of skin cancer

Interdisciplinary applications of nanopharmaceutical sciences have tremendous potential for enhancing pharmacokinetics, efficacy and safety of cancer therapy. The limitations of conventional therapeutic platforms used for skin cancer therapy have been largely overcome by the use of nanoplatforms. This review discusses various nanotechnological approaches experimented for the treatment of skin cancer. The review describes various polymeric, lipidic and inorganic nanoplatforms for efficient therapy of skin cancer. The stimuli-responsive nanoplatforms such as pH-responsive as well as temperature-responsive platforms have also been reviewed. Different strategies for potentiating the nanoparticles application for cancer therapy such as surface engineering, conjugation with drugs, stimulus-responsive and multimodal effect have also been discussed and compared with the available conventional treatments. Although, nanopharmaceuticals face challenges such as toxicity, cost and scale-up, efforts put-in to improve these drawbacks with continuous research would deliver exciting and promising results in coming days.

Colorectal Tumor Microenvironment-Activated Bio-Decomposable and Metabolizable Cu2 O@CaCO3 Nanocomposites for Synergistic Oncotherapy

Rational design of tumor microenvironment (TME)-activated nanocomposites provides an innovative strategy to construct responsive oncotherapy. In colorectal cancer (CRC), the specific physiological features are the overexpressed endogenous H₂ S and slightly acidic microenvironment. Here, a core-shell Cu₂ O@CaCO₃ nanostructure for CRC "turn-on" therapy is reported. With CaCO₃ responsive to pH decomposition and Cu₂ O responsive to H₂ S sulfuration, Cu₂ O@CaCO₃ can be triggered "on" into the therapeutic mode by the colorectal TME. When the CaCO₃ shell decomposes and releases calcium in acidic colorectal TME, the loss of protection from the CaCO₃ shell exposes the Cu₂ O core to be sulfuretted by H₂ S to form metabolizable Cu₃₁ S₁₆ nanocrystals that gain remarkably strong near-infrared absorption. After modifying hyaluronic acid, Cu₂ O@CaCO₃ can achieve synergistic CRC-targeted and TME-triggered photothermal/photodynamic/chemodynamic/calcium-overload-mediated therapy. Moreover, it is found that the generation of hyperthermia and oxidative stress from Cu₂ O@CaCO₃ nanocomposites can efficiently reprogram the macrophages from the M2 phenotype to the M1 phenotype and initiate a vaccine-like immune effect after primary tumor removal, which further induces an immune-favorable TME and intense immune responses for anti-CD47 antibody to simultaneously inhibit CRC distant metastasis and recurrence by immunotherapy.

GSH-Depleted Nanozymes with Hyperthermia-Enhanced Dual Enzyme-Mimic Activities for Tumor Nanocatalytic Therapy

Nanocatalytic therapy, using artificial nanoscale enzyme mimics (nanozymes), is an emerging technology for therapeutic treatment of various malignant tumors. However, the relatively deficient catalytic activity of nanozymes in the tumor microenvironment (TME) restrains their biomedical applications. Here, a versatile and bacteria-like PEG/Ce-Bi@DMSN nanozyme is developed by coating uniform Bi₂ S₃ nanorods (NRs) with dendritic mesoporous silica (Bi₂ S₃ @DMSN) and then decorating ultrasmall ceria nanozymes into the large mesopores of Bi₂ S₃ @DMSN. The nanozymes exhibit dual enzyme-mimic catalytic activities (peroxidase-mimic and catalase-mimic) under acidic conditions that can regulate the TME, that is, simultaneously elevate oxidative stress and relieve hypoxia. In addition, the nanozymes can effectively consume the overexpressed glutathione (GSH) through redox reaction. Photothermal therapy (PTT) is introduced to synergistically improve the dual enzyme-mimicking catalytic activities and depletion of the overexpressed GSH in the tumors by photonic hyperthermia. This is achieved by taking advantage of the desirable light absorbance in the second near-infrared (NIR-II) window of the PEG/Ce-Bi@DMSN nanozymes. Subsequently the reactive oxygen species (ROS)-mediated therapeutic efficiency is significantly improved. Therefore, this study provides a proof of concept of hyperthermia-augmented multi-enzymatic activities of nanozymes for tumor ablation.

Tailored Coupling of Biomineralized CdS Quantum Dots to rGO to Realize Ambient Aqueous Synthesis of a High-Performance Hydrogen Evolution Photocatalyst

Nanocomposite photocatalysts offer a promising route to efficient and clean hydrogen production. However, the multistep, high-temperature, solvent-based syntheses typically utilized to prepare these photocatalysts can limit their scalability and sustainability. Biosynthetic routes to produce functional nanomaterials occur at room temperature and in aqueous conditions, but typically do not produce high-performance materials. We have developed a method to produce a highly efficient hydrogen evolution photocatalyst consisting of CdS quantum dots (QDs) supported on reduced graphene oxide (rGO) via enzyme-based syntheses combined with tuned ligand exchange-mediated self-assembly. All preparation steps are carried out in an aqueous environment at ambient temperature. Size-controlled CdS QDs and rGO are prepared through enzyme-mediated turnover of l-cysteine to HS^- in aqueous solutions of Cd-acetate and graphene oxide, respectively. Exchange of cysteamine for the native l-cysteine ligand capping the CdS QDs drives self-assembly of the now positively charged cysteamine-capped CdS (CdS/CA) onto negatively charged rGO. The use of this short linker molecule additionally enables efficient charge transfer from CdS to rGO, increasing exciton lifetime and, subsequently, photocatalytic activity. The visible-light hydrogen evolution rate of the resulting CdS/CA/rGO photocatalyst is 3300 μmol h^-1 g^-1. This represents, to our knowledge, one of the highest reported rates for a CdS/rGO nanocomposite photocatalyst, irrespective of the synthesis method.

Biodegradable pH-responsive amorphous calcium carbonate nanoparticles as immunoadjuvants for multimodal imaging and enhanced photoimmunotherapy

Development of bioresponsive theranostic nanoparticles to enhance cancer diagnostics and control cancer metastasis is highly desirable. In this study, we developed such a bioresponsive theranostic nanoparticle for synergistic photoimmunotherapy. In particular, these nanoparticles were constructed by embedding indocyanine green (ICG) into Mn2+-doped amorphous calcium carbonate (ACC(Mn)) nanoparticles, followed by loading of the Toll-like-receptor-7 agonist imiquimod (IMQ). The IMQ@ACC(Mn)-ICG/PEG nanoparticles respond to the acidic pH of the tumor microenvironment (TME) and co-deliver ICG and IMQ into the tumor. Selective phototherapy was achieved upon activation using a near-infrared laser. In the presence of IMQ and arising from phototherapeutically treated tumor cells, tumor-associated antigens give rise to a strong antitumor immune response. Reversal of the immunosuppressive TME via H+ scavenging of the tumor through ACC nanoparticles effectively inhibits tumor metastases. Moreover, the combination of ICG and Mn2+ also serves as an advanced contrast agent for cancer multimode imaging. Overall, these bioresponsive nanoparticles provide a promising approach for cancer theranostics with promising potential for future clinical translation.

Dandelion-Inspired Hierarchical Upconversion Nanoplatform for Synergistic Chemo-Photodynamic Therapy In Vitro

Herein, inspired by the structure of a dandelion, we develop a fresh preparation of an upconversion nanoplatform (UCNPs@C₆₀-DOX-FA). The target part folic acid (FA) modified with β-CD-NH₂ can enhance dispersibility and afford the nanoplatform to arrive at the tumor and enter cancer cells easily. After the mouse breast cancer (4T1) cell incubation with the nanoplatform, the abundant glutathione (GSH) in cells cuts the -S-S- bonds like scissors, just as dandelion encountering wind, and the drug doxorubicin (DOX) flows into the nucleus for chemotherapy. Meanwhile, the photodynamic therapy (PDT) effect is enhanced with the decrease content of GSH, which promotes the reactive oxygen species to accumulation. The synergistic chemotherapy and PDT are outstanding in killing 4T1 cells. The rest part UCNPs@C₆₀ possesses excellent biocompatibility and low cytotoxicity. As for cancer diagnosis, UCNPs can be used as a visual imaging agent. Benefited by the delicate structure, all of the functional parts of the nanoplatform go and coordinate well. On account of an FA ligand and the -S-S- bond, the nanoplatform works very well in 4T1 cells while it is able to avoid damage to normal cells since the FA receptors and GSH have overexpression in the 4T1 cells. Thus, this work shows an accessible strategy to design a dandelion-like hierarchical nanoplatform for potential bioimaging-guided synergistic chemo-photodynamic therapy.