Protein@Inorganic Nanodumpling System for High-Loading Protein Delivery with Activatable Fluorescence and Magnetic Resonance Bimodal Imaging Capabilities

Construction of Smart DNA-Based Drug Delivery Systems for Cancer Therapy

Due to the disadvantages of poor targeting, slow action, and low effectiveness of current commonly used cancer treatments, including surgery, chemotherapy, and radiotherapy, researchers have turned to DNA as a biomaterial for constructing drug delivery nanocarriers. DNA is favored for its biocompatibility and programmability. In order to overcome the limitations associated with traditional drug delivery systems (DDSs), researchers have developed smart-responsive DNA DDSs that can control drug release in response to specific physical or chemical stimuli at targeted sites. In this review, a summary of multiple targeted ligand structures is provided, various shapes of stable DNA nanomaterials, and different stimuli-responsive drug release strategies in DNA DDSs. Specifically, targeted cell recognition, in vivo stable transport, and controlled drug release of smart DDSs are focused. Finally, the further development prospects and challenges of clinical application of DNA nanomaterials in the field of smart drug delivery are discussed. The objective of this review is to enhance researchers' comprehension regarding the potential application of DNA nanomaterials in precision drug delivery, with the aim of expediting the clinical implementation of intelligent DDSs.

Histidine-Rich Protein Accelerates the Biomineralization of Zeolitic Imidazolate Frameworks for In Vivo Protein Delivery

Biomineralization of metal-organic frameworks (MOFs) provides a powerful approach for intracellular protein delivery, enabling the study of biological function and therapeutic potential of proteins. However, the potency of this approach is largely challenged by the low efficiency of current strategies for interfacing proteins with MOFs for biomineralization and intracellular delivery. Here, we report a versatile and convenient biomineralization strategy for the rapid encapsulation and enhanced delivery of proteins using MOFs, accelerated by histidine-rich proteins. We demonstrate that the histidine-rich green fluorescent protein (H39GFP) can accelerate the biomineralization of MOFs by promoting the coordination between proteins and metal ions, leading to enhanced protein delivery efficiency up to 15-fold. Moreover, we show that the delivery of H39GFP-fused cytotoxic ribonuclease and bacterial-derived RAS protease can effectively inhibit tumor cell growth. The strategy of promoting the biomineralization of MOFs via histidine-rich proteins for enhanced intracellular delivery could be expanded to other biomacromolecules, advancing their therapeutic potential and the biomedical scope of MOFs.

pH-responsive organic/inorganic hybrid nanocolloids for transcellular delivery of ribonucleolytic payloads toward targeted anti-glioma therapy

Proteins have been appreciated to be a superlative modality of therapeutics in view of their direct roles in regulating diverse sets of biological events, nonetheless, the clinical applications of the proteinic therapeutics have been strictly limited to act on the cell surface receptors owing to their inherent cell-impermeable character of the proteins. To this obstacle, we contrived carboxylation reaction upon the proteins (RNase A) into the overall negatively charged pro-RNase, followed by elaboration of intelligent pH-responsive pro-RNase delivery nanocolloids based on co-precipitation of pro-RNase and Arg-Gly-Asp (RGD)-functionalized poly(ethylene glycol) (PEG)-block-polyanion with aids of inorganic calcium phosphate (CaP). The resulting nanocolloids appeared to actively accumulate into glioma due to the specific binding affinities of RGD and glioma-enriched α_Vβ₃ and α_Vβ₅ integrins. Furthermore, the pH responsiveness to the acidic endolysosomal microenvironment of all compositions of nanocolloids (including: decarboxylation of pro-RNase composition to restore the native RNase A, ionization of CaP composition to elicit osmotic pressure, and charge reversal of PEG-block-polyanion into membrane-disruptive polycation) could stimulate not only efficient endolysosomal escape for translocation into the cytosol but also structural disassembly for ready liberation of the RNase A payloads, eventually exerting non-specific RNA degradation for apoptosis of the affected cells. Systemic dosage of the proposed nanocolloids demonstrated potent anti-tumor efficacies towards xenograft glioma due to massive RNA degradation. Therefore, our proposed RNase A prodrug nanocolloids could represent as a versatile platform for engineering transcellular protein delivery systems, which are expected to spur thriving emergence of a spectrum of proteins in precision intervention of intractable diseases.

Histidine-based coordinative polymers for efficient intracellular protein delivery via enhanced protein binding, cellular uptake, and endosomal escape

Polymers are one of the most promising protein delivery carriers; however, their applications are hindered by low delivery efficacy owing to their undesirable performance in protein binding, cellular uptake and endosomal escape. Here, we designed a series of histidine-based coordinative polymers for efficient intracellular protein delivery. Coordination of metal ions such as Ni²⁺, Zn²⁺, and Cu²⁺ with histidine residues on a polymer greatly improved its performance in protein binding, complex stability, cellular uptake and endosomal escape, therefore achieving highly improved protein delivery efficacy. Among the coordinative polymers, the Zn²⁺-coordinated one exhibited the highest cellular uptake, while the Cu²⁺-coordinated one exhibited the highest endosomal escape. The Ni²⁺-coordinated polymer formed large-sized aggregates with cargo proteins and showed insufficient protein release after endocytosis. The results obtained in this study provided new insight into the development of coordinative polymer-based protein delivery systems.

MnO2@Au nanostructures supported colorimetric biosensing with duplex-specific nuclease-assisted DNA structural transition

Manganese dioxide (MnO₂) nanosheets are regarded as a new class of two-dimensional nanomaterials with several attractive properties with enormous progress in biomedical fields. Gold nanoparticles (AuNPs) are also important biocompatible nanomaterials with unusual optical properties. Hetero-nanostructure of MnO₂ and AuNPs with the medium of DNA is an interesting topic. In this work, the protection of the hetero-nanostructure from salt-induced aggregation is systematically investigated including the effects of sequence length, reagents concentrations, incubation time and temperature. The MnO₂@Au nanostructures are thus applied for the analysis of miRNA. Duplex-specific nuclease (DSN) catalyzed digestion, hybridization chain reaction (HCR) and catalytic hairpin assembly (CHA) are utilized for signal amplification. By finally analyzing the optical responses of the nanocomponents, highly sensitive analysis of target miRNA can be achieved. Excellent analytical performances are attributed to the unique features of MnO₂@Au nanostructures and signal amplification designs. They are promising basis for the construction of novel biosensors for clinical applications.

Immunomodulatory activity of manganese dioxide nanoparticles: Promising for novel vaccines and immunotherapeutics

Manganese (Mn), a nutrient inorganic trace element, is necessary for a variety of physiological processes of animal body due to their important roles in oxidative regulation effects and other aspects of activities. Moreover, manganese ion (Mn²⁺) has widely reported to be crucial for the regulations of different immunological responses, thus showing promising application as potential adjuvants and immunotherapeutics. Taking the advantages of Mn-based biological and immunological activities, Manganese dioxide nanoparticles (MnO₂ NPs) are a new type of inorganic nanomaterials with numerous advantages, including simple preparation, low cost, environmental friendliness, low toxicity, biodegradable metabolism and high bioavailability. MnO₂ NPs, as a kind of drug carrier, have also shown the ability to catalyze hydrogen peroxide (H₂O₂) to produce oxygen (O₂) under acidic conditions, which can enhance the efficacy of radiotherapy, chemotherapy and other therapeutics for tumor treatment by remodeling the tumor microenvironment. More importantly, MnO₂ NPs also play important roles in immune regulations both in innate and adaptive immunity. In this review, we summarize the biological activities of Manganese, followed by the introduction for the biological and medical functions and mechanisms of MnO₂ NPs. What's more, we emphatically discussed the immunological regulation effects and mechanisms of MnO₂ NPs, as well as their potentials to serve as adjuvants and immunomodulators, which might benefit the development of novel vaccines and immunotherapies for more effective disease control.

Self-activated arsenic manganite nanohybrids for visible and synergistic thermo/immuno-arsenotherapy

Arsenotherapy has been clinically exploited to treat a few types of solid tumors despite of acute promyelocytic leukemia using arsenic trioxide (ATO), however, its efficacy is hampered by inadequate delivery of ATO into solid tumors owing to the absence of efficient and biodegradable vehicles. Precise spatiotemporal control of subcellular ATO delivery for potent arsenotherapy thus remains challengeable. Herein, we report the self-activated arsenic manganite nanohybrids for high-contrast magnetic resonance imaging (MRI) and arsenotherapeutic synergy on triple-negative breast cancer (TNBC). The nanohybrids, composed of arsenic‑manganese-co-biomineralized nanoparticles inside albumin nanocages (As/Mn-NHs), switch signal-silent background to high proton relaxivity, and simultaneously afford remarkable subcellular ATO level in acidic and glutathione environments, together with reduced ATO resistance against tumor cells. Then, the nanohybrids enable in vivo high-contrast T₁-weighted MRI signals in various tumor models for delineating tumor boundary, and simultaneously yield efficient arsenotherapeutic efficacy through multiple apoptotic pathways for potently suppressing subcutaneous and orthotopic breast models. As/Mn-NHs exhibited the maximum tumor-to-normal tissue (T/N) contrast ratio of 205% and tumor growth inhibition rate of 88% at subcutaneous 4T1 tumors. These nanohybrids further yield preferable synergistic antitumor efficacy against both primary and metastatic breast tumors upon combination with concurrent thermotherapy. More importantly, As/Mn-NHs considerably induce immunogenic cell death (ICD) effect to activate the immunogenically "cold" tumor microenvironment into "hot" one, thus synergizing with immune checkpoint blockade to yield the strongest tumor inhibition and negligible metastatic foci in the lung. Our study offers the insight into clinically potential arsenotherapeutic nanomedicine for potent therapy against solid tumors.

Charge-Reversible Pro-Ribonuclease Enveloped in Virus-like Synthetic Nanocapsules for Systemic Treatment of Intractable Glioma

We have tailored multifaceted chemistries into the manufacture of artificial virus-like delivery vehicles mimicking viral "intelligent" transportation pathways through sequential biological barriers; these vehicles can acquire the ability to dynamically "program transfer" to their target sites. To accomplish this, we created anionic pro-proteins, which facilitate charge reversal when subject to acidic endosomal pH; in this way, carboxylation reactions are performed on proteins with amine-reactive cis-aconitic anhydride. Electrostatic associations then initiate the envelopment of these pro-proteins into multilayered nanoarchitectural vehicles composed of multiple-segmental block copolycationic cyclic Arg-Gly-Asp (RGD)-poly(ethylene glycol)(PEG)-GPLGVRG-polylysine(thiol). Therefore, upon the pro-proteins' initial binding to the tumors via the protruding RGD ligands, the bio-inert PEG surroundings are detached through the enzymolysis of the intermediate GPLGVRG linkage by tumor-enriched matrix metalloproteinases, unveiling the cationic polylysine palisade and imparting intimate affinities to the anionic cytomembranes of the targeted tumors. Essentially, through their active endocytosis into the subcellular endosomal compartments, the pro-proteins are made capable of retrieving the original amine groups through a charge reversal decarboxylation process, consequently eliciting augmented charge densities (charge nonstoichiometric protein@polylysine(disulfide)) to disrupt the anionic endosomal membranes to facilitate translocation into the cytosol. Eventually, the active protein payloads can be liberated from nonstoichiometric protein@polylysine(thiol) by the disassembly of polylysine palisade upon the cleavage of disulfide crosslinking in response to the very high level of glutathione in the cytosol, thereby contributing toward extreme cytotoxic potency. Hence, our elaborated virus-mimicking platform has demonstrated potent antitumor efficacy through the systemic administration of ribonucleases, which will consequently lead to an innovative new therapeutic method by which proteins could reach intracellular targets.

Embedding Proteins within Spatially Controlled Hierarchical Nanoarchitectures for Ultrasensitive Immunoassay

Modulating the precise self-assembly of functional biomacromolecules is a critical challenge in biotechnology. Herein, functional biomacromolecule-assembled hierarchical hybrid nanoarchitectures in a spatially controlled fashion are synthesized, achieving the biorecognition behavior and signal amplification in the immunoassay simultaneously. Biomacromolecules with sequential assembly on the scaffold through the biomineralization process show significantly enhanced stability, bioactivity, and utilization efficiency, allowing tuning of their functions by modifying their size and composition. The hierarchically hybrid nanoarchitectures show great potential in construction of ultrasensitive immunoassay platforms, achieving a three order-of-magnitude increase in sensitivity. Notably, the well-designed HRP@Ab₂ nanoarchitectures allow for optical immunoassays with a detection range from picogram mL^-1 to microgram mL^-1 on demand, providing great promise for quantitative analysis of both low-abundance and high-residue targets for biomedical applications.

Bi-Functional Gold Nanorod-Protein Conjugates with Biomimetic BSA@Folic Acid Corona for Improved Tumor Targeting and Intracellular Delivery of Therapeutic Proteins in Colon Cancer 3D Spheroids

Gold nanorods (AuNRs) remain well-developed inorganic nanocarriers of small molecules for a plethora of biomedical and therapeutic applications. However, the delivery of therapeutic proteins using AuNRs with high protein loading capacity (LC), serum stability, excellent target specificity, and minimal off-target protein release is not known. Herein, we report two bi-functional AuNR-protein nanoconjugates, AuNR@EGFP-BSA_FA and AuNR@RNaseA-BSA_FA, supramolecularly coated with folic acid-modified BSA (BSA_FA) acting as biomimetic protein corona to demonstrate targeted cytosolic delivery of enhanced green fluorescent protein (EGFP) and therapeutic ribonuclease A enzyme (RNase A) in their functional forms. AuNR@EGFP-BSA_FA and AuNR@RNaseA-BSA_FA exhibit high LCs of ∼42 and ∼54%, respectively, increased colloidal stability, and rapid protein release in the presence of biological thiols. As a nanocarrier, AuNR@EGFP-BSA_FA and AuNR@RNaseA-BSA_FA show resistance to corona formation in high-serum media even after 24 h, guaranteeing a greater circulation lifetime. Folate receptor-targeting BSA_FA on the AuNR surface facilitates the receptor-mediated internalization, followed by the release of EGFP and RNase A in HT29 cells. The green fluorescence dispersed throughout the cell's cytoplasm indicates successful cytosolic delivery of EGFP by AuNR@EGFP-BSA_FA. AuNR@RNaseA-BSA_FA-mediated therapeutic RNase A delivery in multicellular 3D spheroids of HT29 cells exhibits a radical reduction in the cellular RNA fluorescence intensity to 38%, signifying RNA degradation and subsequent cell death. The versatile nanoformulation strategy in terms of the anisotropic particle morphology, protein type, and ability for targeted delivery in the functional form makes the present AuNR-protein nanoconjugates a promising platform for potential application in cancer management.

Janus Magnetic Nanoplatform for Magnetically Targeted and Protein/Hyperthermia Combination Therapies of Breast Cancer

Protein therapeutics have been considered a promising strategy for cancer treatment due to their highly specific bioactivity and few side effects. Unfortunately, the low physiological stability and poor membrane permeability of most protein drugs greatly limit their clinical application. Furthermore, single-modality protein therapeutics show insufficient efficacy. To address these issues, Janus magnetic mesoporous silica nanoparticles (Janus MSNNPs) were developed to preload ribonuclease A (RNaseA) to simultaneously realize the magnetically enhanced delivery of protein drugs and magnetic hyperthermia-enhanced protein therapy. Janus MSNNPs showed a high RNaseA loading ability and pH-responsive drug release behavior. Furthermore, an external magnetic field could remarkably enhance the therapeutic effect of RNaseA-loaded Janus MSNNPs due to the improved intracellular internalization of RNaseA. Importantly, Janus MSNNPs possessed an outstanding magnetic hyperthermia conversion efficiency, which could generate hyperthermia under an alternating magnetic field, effectively supplementing protein therapy by a combined effect. In vitro and in vivo experiments confirmed the high anticancer outcome and low side effects of this intriguing strategy for breast cancer based on Janus MSNNPs. Hence, Janus MSNNPs might be an effective and safe nanoplatform for magnetically combined protein therapy.

In vivo targeted delivery of antibodies into cancer cells with pH-responsive cell-penetrating poly(disulfide)s

Cell-penetrating poly(disulfide)s (CPDs) are promising vehicles for cytosolic delivery of proteins. However, currently available arginine-rich CPD has rarely been reported for systemic delivery due to its "always" positive charge. Herein, we developed pH-responsive CPDIMD that executes tumor targeting delivery via protonation of imidazole groups within the acidic tumor microenvironment.

Hydroxyapatite-binding albumin nanoclusters for enhancing bone tumor chemotherapy

Hydroxyapatite-binding albumin nanoclusters (NCs) were developed for improving the anticancer agent accumulation in bone tumors. Human serum albumin (HSA) was decorated with alendronate (AD), and doxorubicin (DOX)-loaded NCs (HSA-AD/DOX) were fabricated via the ball-milling technology, an innovative nano-fabrication method by which more than 90% of the secondary structures of albumin can be preserved. The targeting ability of NCs was confirmed using a novel in vitro bone cancer model, wherein hydroxyapatite and collagen, the major components of the bone matrix representing the highly mineralized bone tumor microenvironment, were co-cultured with HOS/MNNG, a human osteosarcoma cell line. The binding affinity of HSA-AD/DOX to hydroxyapatite was evaluated based on the DOX binding efficiency. HSA-AD/DOX showed a 5.04-fold higher affinity than HSA/DOX. The enhanced distribution of HSA-AD/DOX to bone tumors was verified using a newly developed mouse model bearing HOS/MNNG tumors with hydroxyapatite beads. HSA-AD/DOX led to a 52.0% increase in tumor accumulation compared to that of the unmodified HSA/DOX. This is mainly due to the hydroxyapatite-binding affinity of the AD moiety, which is supported by histological analyses performed on the dissected tumors. Furthermore, HSA-AD/DOX changed the protein expression patterns of the tumors, implying the enhanced apoptotic process. Overall, the targeting ability of HSA-AD/DOX are effectively translated into improved therapeutic efficacy in bone tumor-xenografted mice, suggesting that the developed NCs are a promising delivery system for bone tumor treatment.

“Spear and Shield in One” Nanochaperone Enables Protein to Navigate Multiple Biological Barriers for Enhanced Tumor Synergistic Therapy

Protein therapeutics have been viewed as powerful candidates for cancer treatment by virtue of highly specific bioactivity and minimized adverse effects. However, the intracellular delivery of protein drugs remains enormously...

Discovery of a highly selective and ultra-sensitive colorimetric fluorescent probe for malononitrile and its applications in living cells and zebrafish

A selective and ultra-sensitive colorimetric fluorescent probe was discovered to detect malononitrile in living cells and zebrafish.

Co-Delivery of Paclitaxel and shMCL-1 by Folic Acid-Modified Nonviral Vector to Overcome Cancer Chemotherapy Resistance

Acquired chemoresistance presents a major clinical impediment, which is an urgent problem to be solved. Interestingly, myeloma cell leukemia-1 (MCL-1) and folate receptor expression levels are higher in chemotherapy-resistant patients than in pretreatment patients. In this study, a multifunctional folic acid (FA)-targeting core-shell structure is presented for simultaneous delivery of shMCL-1 and paclitaxel (PTX). The transfection efficiency of shMCL-1 with the FA-targeting delivery system is higher than with a nontargeting delivery system in Skov3 and A2780T cells. The FA-targeting system significantly inhibits cell growth, blocks cell cycles, and promotes apoptosis of cancer cells in vitro. The mechanisms involved in inhibiting growth are related to Bcl-2/Bax and cdc2/Cyclin B1 pathways. An analysis of RNA sequencing suggests that shMCL-1 reverses chemoresistance through regulating genes such as regulator of chromosome condensation 2 (RCC2). The synergetic effect of shMCL-1 and PTX effectively inhibits tumor growth in both PTX-resistant and normal cancer models by inducing tumor apoptosis, inhibiting proliferation, and limiting tumor angiogenesis. The study results indicate that a FA-targeting delivery system combining shMCL-1 with PTX can simultaneously target tumor sites and restore the sensitivity of chemotherapy-resistant cancer to PTX. These findings have important implications for patients with normal or PTX-resistant cancer.

Tetraphenylethylene-Featured Fluorescent Supramolecular Nanoparticles for Intracellular Trafficking of Protein Delivery and Neuroprotection

The delivery of protein into mammalian cells enables the dissection and manipulation of biological processes; however, this potency is challenged by the lack of an efficient protein delivery tool and a means to monitor its intracellular trafficking. Herein, we report that the hierarchical self-assembly of tetraphenylethylene (TPE)-featured metal-organic cages (MOCs) and β-cyclodextrin-conjugated polyethylenimine can generate fluorescent supramolecular nanoparticles (FSNPs) to deliver protein into neural cells, a cell line that is hard to transfect using conventional strategy. Further, the aggregation-induced emission (AIE) of TPE enabled the fluorescent monitoring of cytosolic protein release. It is found that FSNPs can deliver and release protein into cytosol for subcellular targeting as fast as 18 h post-delivery. Moreover, the delivery of molecular chaperone DJ-1 using FSNPs activates MAPK/ERK signaling of neural cells to protect cells from oxidative stress.

An efficient photochemotherapy nanoplatform based on the endogenous biosynthesis of photosensitizer in macrophage-derived extracellular vesicles

Extracellular vesicles (EVs) have been emerged as versatile drug delivery vehicles due to their outstanding biocompatibility and long-term circulation, yet are constrained with low targeting property and inefficient loading capacity from post-synthetic passive EVs encapsulation. Herein, we report a simple and feasible in situ biosynthetic approach to encapsulate tumor-targeting folate (FA)-modified EVs with intracellularly produced protoporphyrin X (PpIX) and doxorubicin (DOX). As compared with the traditional directly drug-incubated or drug-electroporated EVs, these biosynthesized EVs revealed high drug-loading efficiency with minimized structural and functional perturbations. Our multifunctional EVs revealed the enhanced accumulation and penetration into deep tumor parenchyma, as well as the strengthened immune response to ablate orthotopic and metastatic tumors, thus realizing the more reliable photochemotherapy. As an intelligent multi-mode therapeutic system, our biosynthetic EVs could be engineered with more therapeutic agents and show great promise for biomedicine applications.

Multimodules integrated functional DNA nanomaterials for intelligent drug delivery

Deoxyribonucleic acid (DNA) has been an emerging building block to construct functional biomaterials. Due to their programmable sequences and rich responsiveness, DNA has attracted rising attention in the construction of intelligent nanomaterials with predicable nanostructure and adjustable functions, which has shown great potential in drug delivery. On the one hand, the DNA sequences with molecule recognition, responsiveness, and therapeutic efficacy can be easily integrated to the framework of DNA nanomaterials by sequence designing; on the other hand, the rich chemical groups on DNA molecules provide binding points for other functional units. In this review, we divided the functionalization modules in the construction of DNA nanomaterials into three types, including targeting modules, responsive modules, and therapeutic modules. Based on these modules, five DNA kinds of representative nanomaterials applied in drug delivery were introduced, including DNA nanogel, DNA origami, DNA framework, DNA nanoflower, and DNA hybrid nanosphere. Finally, we discussed the challenges in the transition of DNA materials to clinical applications. We expect that this review can help readers to obtain a deeper understanding of DNA materials, and further promote the development of these intelligent materials to real world's application. This article is categorized under: Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Metal-Coordinated Supramolecular Self-Assemblies for Cancer Theranostics

Metal-coordinated supramolecular nanoassemblies have recently attracted extensive attention as materials for cancer theranostics. Owing to their unique physicochemical properties, metal-coordinated supramolecular self-assemblies can bridge the boundary between traditional inorganic and organic materials. By tailoring the structural components of the metal ions and binding ligands, numerous multifunctional theranostic nanomedicines can be constructed. Metal-coordinated supramolecular nanoassemblies can modulate the tumor microenvironment (TME), thus facilitating the development of TME-responsive nanomedicines. More importantly, TME-responsive organic-inorganic hybrid nanomaterials can be constructed in vivo by exploiting the metal-coordinated self-assembly of a variety of functional ligands, which is a promising strategy for enhancing the tumor accumulation of theranostic molecules. In this review, recent advancements in the design and fabrication of metal-coordinated supramolecular nanomedicines for cancer theranostics are highlighted. These supramolecular compounds are classified according to the order in which the coordinated metal ions appear in the periodic table. Furthermore, the prospects and challenges of metal-coordinated supramolecular self-assemblies for both technical advances and clinical translation are discussed. In particular, the superiority of TME-responsive nanomedicines for in vivo coordinated self-assembly is elaborated, with an emphasis on strategies that enhance the accumulation of functional components in tumors for an ideal theranostic outcome.

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.

Biomineralization: An Opportunity and Challenge of Nanoparticle Drug Delivery Systems for Cancer Therapy

Biomineralization is a common process in organisms to produce hard biomaterials by combining inorganic ions with biomacromolecules. Multifunctional nanoplatforms are developed based on the mechanism of biomineralization in many biomedical applications. In the past few years, biomineralization-based nanoparticle drug delivery systems for the cancer treatment have gained a lot of research attention due to the advantages including simple preparation, good biocompatibility, degradability, easy modification, versatility, and targeting. In this review, the research trends of biomineralization-based nanoparticle drug delivery systems and their applications in cancer therapy are summarized. This work aims to promote future researches on cancer therapy based on biomineralization. Rational design of nanoparticle drug delivery systems can overcome the bottleneck in the clinical transformation of nanomaterials. At the same time, biomineralization has also provided new research ideas for cancer treatment, i.e., targeted therapy, which has significantly better performance.

Polyphenol-Based Nanoparticles for Intracellular Protein Delivery via Competing Supramolecular Interactions

Intracellular delivery of proteins is a promising strategy for regulating cellular behavior and therefore has attracted interest for biomedical applications. Despite the emergence of various nanoparticle-based intracellular delivery approaches, it remains challenging to engineer a versatile delivery system capable of responding to various physiological triggers without the need for complex chemical synthesis of the delivery system. Herein, we develop a template-mediated supramolecular assembly strategy to synthesize protein-polyphenol nanoparticles (NPs) capable of endosomal escape and subsequent protein release in the cytosol. These NPs are stable in serum and undergo surface charge reversal from negative to positive in acidic environments, leading to spontaneous endosomal escape. In the cytosol, endogenous small peptides and amino acids with relatively high charge densities, such as glutathione, trigger NP disassembly through competitive supramolecular interactions, thereby releasing functional bioactive proteins, as validated using cytochrome C and β-galactosidase. The versatility of the present strategy in terms of nanoparticle size, protein type, and functional protein delivery makes this a promising platform for potential application in the field of protein therapeutics.

Nanostructured manganese dioxide for anticancer applications: preparation, diagnosis, and therapy

Nanostructured manganese dioxide (MnO₂) has attracted extensive attention in the field of anticancer applications. As we all know, the tumor microenvironment is usually characterized by a high glutathione (GSH) concentration, overproduced hydrogen peroxide (H₂O₂), acidity, and hypoxia, which affect the efficacy of many traditional treatments such as chemotherapy, radiotherapy, and surgery. Fortunately, as one kind of redox-active nanomaterial, nanostructured MnO₂ has many excellent properties such as strong oxidation ability, excellent catalytic activity, and good biodegradability. It can be used effectively in diagnosis and treatment when it reacts with some harmful substances in the tumor site. It can not only enhance the therapeutic effect but also adjust the tumor microenvironment. Therefore, it is necessary to present the recent achievements and progression of nanostructured MnO₂ for anticancer applications, including preparation methods, diagnosis, and treatment. Special attention was paid to photodynamic therapy (PDT), bioimaging and cancer diagnosis (BCD), and drug delivery systems (DDS). This review is expected to provide helpful guidance on further research of nanostructured MnO₂ for anticancer applications.

Construction of three-dimensional interleaved protein hetero-superlattices in solution by cooperative electrostatic and aromatic stacking interactions

HYPOTHESIS

Hierarchical assembly of naturally occurring assemblies is accurate and responsible for performing various cellular functions. However, Nature's wisdom in navigating the assembly process to desired protein assemblies by the cooperation of multiple noncovalent interactions has been underexploited for protein superstructures constructions. Owing to the chemical diversity of noncovalent interactions, it should be possible to fabricate protein assemblies with novel properties in high efficiency through the cooperation of different noncovalent interaction.

EXPERIMENTS

Both charged residues and aromatic residues are introduced on the exterior surface of ferritin centered at their symmetry axes, mixing of complementary variants forms ordered assemblies through the cooperation of two kinds of chemical-diverse noncovalent interactions. The assemblies were further characterized in terms of their assembly behavior, structure, size, assembly kinetics, properties and stabilities.

FINDINGS

We utilized both electrostatic and π-π stacking interactions between complementary nanocages to cooperatively trigger the self-assembly into predesigned interleaved hetero-superlattices which exhibit high electrolyte stability and thermal stability. The size of the hetero-superlattices can be well controlled with ranges from nanometers to micrometers in solution in response to external stimuli such as pH and salt concentration. The hetero-superlattice may have the potential applications in hybrid bio-templating, light-harvesting and compartmentalized encapsulation.