Autonomous Feedback-Driven Engineered DNAzyme-Coated Trojan Horse-like Nanocapsules for On-Demand CRISPR/Cas9 Delivery

Manipulating the expression of cellular genes through efficient CRISPR/Cas9 delivery is rapidly evolving into a desirable tumor therapeutics. The exposure of CRISPR/Cas9 to a complex external environment poses challenges for conventional delivery carriers in achieving responsive and accurate release. Here, we report a Trojan horse-like nanocapsule for the on-demand delivery of CRISPR/Cas9 in a microRNA-responsive manner, enabling precise tumor therapy. The nanocapsule comprises a nanoassembled, engineered DNAzyme shell encasing a Cas9/sgRNA complex core. The DNAzyme, functioning as a catalytic unit, undergoes a conformational change in the presence of tumor-associated microRNA, followed by activating a positive feedback-driven autonomous catabolic cycle of the nanocapsule shell. This catabolic cycle is accomplished through chain reactions of DNAzyme "cleavage-hybridization-cleavage", which ensures sensitivity in microRNA recognition and effective release of Cas9/sgRNA. Utilizing this Trojan horse-like nanocapsule, as low as 1.7 pM microRNA-21 can trigger the on-demand release of Cas9/sgRNA, enabling the specific editing of the protumorigenic microRNA coding gene. The resulting upregulation of tumor suppressor genes induces apoptosis in tumor cells, leading to significant inhibition of tumor growth by up to 75.94%. The Trojan horse-like nanocapsule, with superior programmability and biocompatibility, is anticipated to serve as a promising carrier for tailoring responsive gene editing systems, achieving enhanced antitumor specificity and efficacy.

Bio-functionalized nanocolloids of ZnS quantum dot/amine-rich polypeptides for bioimaging cancer cells with antibacterial activity: "seeing is believing"

Among almost 200 types of cancers, glioma is considered one of the most common forms of malignant tumors located in the central nervous system (CNS). Glioblastoma (GBM), one of the deadliest types of brain cancer, remains one of the challenges faced by oncologists. Thus, smartly designed nanomaterials biofunctionalized with polypeptides can offer disruptive strategies relying on the earliest possible diagnosis ("seeing is believing") combined with more efficient therapies for fighting cancer cells. To worsen this scenario, bacteria infections very often pose a serious challenge to cancer-immunodeficient patients under chemotherapy. Thus, in this research, we report for the first time the design and synthesis of novel nanoconjugates composed of photoluminescent ZnS quantum dots (ZnS QDs), which were directly surface biofunctionalized with epsilon-poly-l-lysine (εPL), acting as an amine-rich cell-penetrating peptide (CPP) and antimicrobial peptide agent (AMP). These nanoconjugates (named ZnS@CPP-AMP) were produced through a one-step facile, eco-friendly, and biocompatible colloidal aqueous process to be applied as a proof of concept as nanoprobes for bioimaging GBM cancer cells (U87-MG) associated with synergic antibacterial activity. They were characterized regarding their physicochemical and optical properties associated with the biological activity. The results demonstrated that chemically stable aqueous colloidal nanoconjugates were effectively formed, resembling core-shell (inorganic, ZnS, organic, εPL) nanostructures with positively surface-charged features due to the cationic nature of the amine-rich polypeptide. More importantly, they demonstrated photoluminescent activity, cytocompatibility in vitro, and no significant intracellular reactive oxygen species (ROS) generation. These ZnS@CPP-AMP nanocolloids behaved as fluorescent nanoprobes for bioimaging GBM cancer cells, where the polycationic nature of the εPL biomolecule may have enhanced the cellular uptake. Additionally, they displayed mild antibacterial growth inhibition due to electrostatic interactions with bacterial membranes. Thus, it can be envisioned that these novel photoluminescent colloidal nanoconjugates offer novel nanoplatforms that can be specifically targeted with biomolecules for bioimaging to diagnose highly lethal cancers, such as GBM, and as an adjuvant in antibacterial therapy.

One-Step Fabrication of Coconut-Like Capsules via Competitive Reactions at an All-Aqueous Interface for Enzyme Immobilization

A concept of interfacial competitive reaction between biomineralization and alginate gelation at an all-aqueous single-emulsion droplet interface to prepare robust coconut-like capsules (inner hard wall and outer soft wall) is developed. The concept is further applied for enzyme immobilization with high encapsulation efficiency, enzyme loading, mass transfer coefficient, and recyclability. The thickness and swelling properties of the shell are simply tunable by a competitive reaction. Our platform may open a green, facile, and efficient way to prepare organic-inorganic hybrid sustainable materials with tailored compositions and structures.

Real-time SERS monitoring anticancer drug release along with SERS/MR imaging for pH-sensitive chemo-phototherapy

In situ and real-time monitoring of responsive drug release is critical for the assessment of pharmacodynamics in chemotherapy. In this study, a novel pH-responsive nanosystem is proposed for real-time monitoring of drug release and chemo-phototherapy by surface-enhanced Raman spectroscopy (SERS). The Fe3O4@Au@Ag nanoparticles (NPs) deposited graphene oxide (GO) nanocomposites with a high SERS activity and stability are synthesized and labeled with a Raman reporter 4-mercaptophenylboronic acid (4-MPBA) to form SERS probes (GO-Fe3O4@Au@Ag-MPBA). Furthermore, doxorubicin (DOX) is attached to SERS probes through a pH-responsive linker boronic ester (GO-Fe3O4@Au@Ag-MPBA-DOX), accompanying the 4-MPBA signal change in SERS. After the entry into tumor, the breakage of boronic ester in the acidic environment gives rise to the release of DOX and the recovery of 4-MPBA SERS signal. Thus, the DOX dynamic release can be monitored by the real-time changes of 4-MPBA SERS spectra. Additionally, the strong T2 magnetic resonance (MR) signal and NIR photothermal transduction efficiency of the nanocomposites make it available for MR imaging and photothermal therapy (PTT). Altogether, this GO-Fe3O4@Au@Ag-MPBA-DOX can simultaneously fulfill the synergistic combination of cancer cell targeting, pH-sensitive drug release, SERS-traceable detection and MR imaging, endowing it great potential for SERS/MR imaging-guided efficient chemo-phototherapy on cancer treatment.

Bioengineered Carboxymethylcellulose-Peptide Hybrid Nanozyme Cascade for Targeted Intracellular Biocatalytic-Magnetothermal Therapy of Brain Cancer Cells

Glioblastoma remains the most lethal form of brain cancer, where hybrid nanomaterials biofunctionalized with polysaccharide peptides offer disruptive strategies relying on passive/active targeting and multimodal therapy for killing cancer cells. Thus, in this research, we report for the first time the rational design and synthesis of novel hybrid colloidal nanostructures composed of gold nanoparticles stabilized by trisodium citrate (AuNP@TSC) as the oxidase-like nanozyme, coupled with cobalt-doped superparamagnetic iron oxide nanoparticles stabilized by carboxymethylcellulose ligands (Co-MION@CMC) as the peroxidase-like nanozyme. They formed inorganic-inorganic dual-nanozyme systems functionalized by a carboxymethylcellulose biopolymer organic shell, which can trigger a biocatalytic cascade reaction in the cancer tumor microenvironment for the combination of magnetothermal-chemodynamic therapy. These nanoassemblies were produced through a green aqueous process under mild conditions and chemically biofunctionalized with integrin-targeting peptide (iRDG), creating bioengineered nanocarriers. The results demonstrated that the oxidase-like nanozyme (AuNP) was produced with a crystalline face-centered cubic nanostructure, spherical morphology (diameter = 16 ± 3 nm), zeta potential (ZP) of -50 ± 5 mV, and hydrodynamic diameter (DH) of 15 ± 1 nm. The peroxide-like nanostructure (POD, Co-MION@CMC) contained an inorganic crystalline core of magnetite and had a uniform spherical shape (2R = 7 ± 1 nm) which, summed to the contribution of the CMC shell, rendered a hydrodynamic diameter of 45 ± 4 nm and a negative surface charge (ZP = -41 ± 5 mV). Upon coupling both nanozymes, water-dispersible colloidal supramolecular vesicle-like organic-inorganic nanostructures were produced (AuNP//Co-MION@CMC, ZP = -45 ± 4 mV and DH = 28 ± 3 nm). They confirmed dual-nanozyme cascade biocatalytic activity targeted by polymer-peptide conjugates (AuNP//Co-MION@CMC_iRGD, ZP = -29 ± 3 mV and DH = 60 ± 4 nm) to kill brain cancer cells (i.e., bioenergy "starvation" by glucose deprivation and oxidative stress through reactive oxygen species generation), which was boosted by the magneto-hyperthermotherapy effect when submitted to the alternating magnetic field (i.e., induced local thermal stress by "nanoheaters"). This groundwork offers a wide avenue of opportunities to develop innovative theranostic nanoplatforms with multiple integrated functionalities for fighting cancer and reducing the harsh side effects of conventional chemotherapy.

Hybrid Alginate-Brushite Beads Easily Catalyze the Knoevenagel Condensation On-Water

An innovative hybrid organic-inorganic material composed of alginate-brushite xerogel beads was successfully applied for the catalysis of the Knoevenagel condensation. The catalyst was derived from phosphated alginate xerogel microspheres formed from the ionotropic gelling effect of phosphated alginate. To this end, alginate was phosphated by the addition of diammonium hydrogen phosphate in a 1% w/w alginate gel. The phosphated alginate was subsequently precipitated by chelation of Ca²⁺ cations, generating a phosphated alginate hydrogel microsphere, which was washed and dried, forming hybrid organic-inorganic xerogel beads as a crystalline phosphate-rich mineral fraction covered by alginate. X-ray diffraction analysis revealed that the crystalline inorganic matrix of the material was composed predominantly of brushite. SEM analysis revealed plate-like, ribbon-like, or needle-like morphologies in the hybrid alginate-brushite beads. The hybrid material was tested as a catalyst for Knoevenagel condensation, which was performed ″on-water″ under mild conditions with aromatic aldehydes and activated methylene compounds, giving high yields (up to 97%). The reaction rate and product yield increased together with the reaction temperature for all reagents. The recyclable solid catalyst was effective for three runs, revealing the potential of the innovative hybrid catalyst as an eco-friendly heterogeneous catalyst.

Carboxymethylcellulose biofunctionalized ternary quantum dots for subcellular-targeted brain cancer nanotheranostics

Among the most lethal forms of cancer, malignant brain tumors persist as one of the greatest challenges faced by oncologists, where nanotechnology-driven theranostics can play a critical role in developing novel polymer-based supramolecular nanoarchitectures with multifunctional and multi-modal characteristics to fight cancer. However, it is virtually a consensus that, besides the complexity of active delivering anticancer drugs by the nanocarriers to the tumor site, the current evaluation methods primarily relying on in vitro assays and in vivo animal models have been accounted for the low translational effectiveness to clinical applications. In this view, the chick chorioallantoic membrane (CAM) assay has been increasingly recognized as one of the best preclinical models to study the effects of anticancer drugs on the tumor microenvironment (TME). Thus, in this study, we designed, characterized, and developed novel hybrid nanostructures encompassing chemically functionalized carboxymethylcellulose (CMC) with mitochondria-targeting pro-apoptotic peptide (KLA) and cell-penetrating moiety (cysteine, CYS) with fluorescent inorganic semiconductor (Ag-In-S, AIS) for simultaneously bioimaging and inducing glioblastoma cancer cell (U-87 MG, GBM) death. The results demonstrated that the CMC-peptide macromolecules produced supramolecular vesicle-like nanostructures with aqueous colloidal stability suitable as nanocarriers for passive and active targeting of cancer tumors. The optical properties and physicochemical features of the nanoconjugates confirmed their suitability as photoluminescent nanoprobes for cell bioimaging and intracellular tracking. Moreover, the results in vitro demonstrated a notable killing activity towards GBM cells of cysteine-bearing CMC conjugates coupled with pro-apoptotic KLA peptides. More importantly, compared to doxorubicin (DOX), a model anticancer drug in chemotherapy that is highly toxic, these innovative nanohybrids nanoconjugates displayed higher lethality against U-87 MG cancer cells. In vivo CAM assays validated these findings where the nanohybrids demonstrated a significant reduction of GBM tumor progression (41% area) and evidenced an antiangiogenic activity. These results pave the way for developing polymer-based hybrid nanoarchitectonics applied as targeted multifunctional theranostics for simultaneous imaging and therapy against glioblastoma while possibly reducing the systemic toxicity and side-effects of conventional anticancer chemotherapeutic agents.

In-situ synthesis of metal nanoparticle embedded soft hybrid materials via eco-benign approach

The unique optical and electronic properties of metal nanoparticles and tunable properties of the organic templates encourage the scientific community to generate metal nanoparticle embedded soft hybrid materials for various novel utilities. Here, we discuss the in-situ synthesis of metal nanoparticle embedded soft hybrid materials via eco-benign approach which exclude the use of toxic reducing/capping agents or toxic reaction media. In this protocol, the gel matrix composed of benign organic templates act as reducing as well as stabilizing agent for the in-situ generation and stabilization of metal nanoparticles. As the incorporation of metal salts (as nanoparticle precursor) in the gel medium is required in this process, in most of the cases aqueous media were used for the generation of metal nanoparticle embedded soft hybrid materials. This discussion includes interesting findings from our laboratory where hybrid gel matrix composed of renewable chemicals was utilized for the in-situ synthesis of palladium nanoparticle embedded soft trihybrid material. The hybrid gel matrix rich in polyphenols/flavonoids was exploited to generate palladium nanoparticle embedded trihybrid gel through in-situ reduction of doped Pd (II) salts to stable PdNPs. The xerogel of this trihybrid material was utilized as recyclable heterogeneous catalyst for C-C coupling reaction in air under phosphene free condition and reduction reaction.

Visual naked-eye detection of SARS-CoV-2 RNA based on covalent organic framework capsules

The ongoing outbreak of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted that new diagnosis technologies are crucial for controlling the spread of the disease. Especially in the resources-limit region, conveniently operated detection methods such as "naked-eye" detection are urgently required that no instrument is needed. Herein, we have designed a novel and facile strategy to fabricate covalent organic framework (COF) capsules, which can be utilized to establish a new colorimetric assay for naked-eye detection of SARS-CoV-2 RNA. Specifically, we employ the digestible ZIF-90 as the sacrificial template to prepare the hollow COF capsules for horseradish peroxidase (HRP) encapsulation. The fabricated COF capsules can provide an appropriate microenvironment for the enzyme molecules, which may improve the conformational freedom of enzymes, enhance the mass transfer, and endow the enzyme with high environmental resistance. With such design, the proposed assay exhibits outstanding analytical performance for the detection of SARS-CoV-2 RNA in the linear range from 5 pM to 50 nM with a detection limit of 0.28 pM which can go parallel to qTR-PCR analysis. Our method also possesses excellent selectivity and reproducibility. Moreover, this method can also be served to analyze the clinical samples, and can successfully differentiate COVID-19 patients from healthy people, suggesting the promising potential in clinical diagnosis.

Microfluidic technologies for nanoparticle formation

Functional nanoparticles (NPs) hold immense promise in diverse fields due to their unique biological, chemical, and physical properties associated with size or morphology. Microfluidic technologies featuring precise fluid manipulation have become versatile toolkits for manufacturing NPs in a highly controlled manner with low batch-to-batch variability. In this review, we present the fundamentals of microfluidic fabrication strategies, including mixing-, droplet-, and multiple field-based microfluidic methods. We highlight the formation of functional NPs using these microfluidic reactors, with an emphasis on lipid NPs, polymer NPs, lipid-polymer hybrid NPs, supramolecular NPs, metal and metal-oxide NPs, metal-organic framework NPs, covalent organic framework NPs, quantum dots, perovskite nanocrystals, biomimetic NPs, etc. we discuss future directions in microfluidic fabrication for accelerated development of functional NPs, such as device parallelization for large-scale NP production, highly efficient optimization of NP formulations, and AI-guided design of multi-step microfluidic reactors.

Dopamine-Mediated Biomineralization of Calcium Phosphate as a Strategy to Facilely Synthesize Functionalized Hybrids

Organic-inorganic hybrid materials have been considered to be promising carriers or immobilization matrixes for biomolecules due to their high efficiency and significantly enhanced activities and stabilities of biomolecules. Here, the well-defined dopamine/calcium phosphate organic-inorganic hybrids (DACaPMFs) are fabricated via one-pot dopamine-mediated biomineralization, and their structure and properties are also characterized. Direct stochastic optical reconstruction microscopy (dSTORM) is first used to probe the distribution of organic components in these hybrids. Combined with spectroscopic data, the direct observation of dopamine in the hybrids helps to understand the formation of a physical chemistry mechanism of the biomineralization. The obtained DACaPMFs with multiple-level pores allow the loading of doxorubicin with a high loading efficiency and a pH-responsive property. Furthermore, thrombin is entrapped by the hybrids to prove the controlled release. It is expected that such organic-inorganic hybrid materials may hold great promise for application in drug delivery as well as scaffold materials in bone tissue engineering and hemostatic material.

Liquid Nanoparticles: Manipulating the Nucleation and Growth of Nanoscale Droplets

By manipulating the nucleation and growth of solid materials, the synthesis of various sophisticated nanostructures has been achieved. Similar methodology, if applied to liquids, could enable the mass-production and control of ultra-small droplets at the scale of nanoparticles (10^-18  L or below). It would be highly desirable since droplets play a fundamental role in numerous applications. Here we present a general strategy to synthesize and manipulate nanoscale droplets, similar to what has been done to solid nanoparticles in classic solution-synthesis. It was achieved by a solute-induced phase separation which initiates the nucleation of droplets from a homogeneous solution. These liquid nanoparticles have great potentials to be manipulated like their solid counterparts, borrowing from the vast methodologies of nanoparticle synthesis, such as burst nucleation, seeded growth, and co-precipitation. Liquid nanoparticles also serve as a general synthetic platform, to fabricate nanoreactors, drug-loaded carriers, and other hollow nanostructures with a variety of shell materials.

Single and Bilayer Polyacrylamide Hydrogel-Based Microcapsules for the Triggered Release of Loads, Logic Gate Operations, and Intercommunication between Microcapsules

A method to assemble loaded stimuli-responsive DNA-polyacrylamide hydrogel-stabilized microcapsules is presented. The method involves coating substrate-loaded CaCO₃ microparticles, functionalized with nucleic acid promoter units, and cross-linking DNA-modified polyacrylamide chains on the microcapsules, using the hybridization chain reaction (HCR) to yield the DNA-cross-linked hydrogel coating. Dissolution of the CaCO₃ particles generated the substrate-loaded hydrogel-protected microcapsules. The microcapsule-hydrogel shells include engineered stimuli-responsive oligonucleotide cross-linkers that control the stiffness of the hydrogel shells, allowing the triggered release of the loads. One approach includes the incorporation of cofactor-dependent DNAzyme units into the cross-linked hydrogel layers (cofactor = Mg²⁺ ions, Zn²⁺ ions, or histidine) as stimuli-responsive units. Cleavage of the cross-linking DNAzyme substrates by the respective cofactors yields hydrogel coatings with a reduced stiffness and higher porosity that allow the release of the loads. A further approach involved the application of the HCR process to assemble the bilayer hydrogel microcapsules that are unlocked by two cooperative triggers. Bilayer microcapsules consisting of a K⁺ ions-stabilized G-quadruplex/18-crown-6-ether (CE) responsive layer and a Mg²⁺ ion DNAzyme-responsive layers are presented. Unlocking and locking of the G-quadruplex cross-linked layer by 18-crown-6-ether and K⁺ ions, respectively, in the presence of Mg²⁺ ions allow the switchable controlled release of the load. In addition, the intercommunication of two kinds of stimuli-responsive bilayer hydrogel microcapsules carrying two different loads (tetramethylrhodamine-dextran, TMR-D, and CdSe/ZnS quantum dots) is demonstrated. The intercommunication process involves the stimuli-triggered generation of "information transfer" strands from one microcapsule to another that activate the release of the loads.

Thermoplasmonic-Triggered Release of Loads from DNA-Modified Hydrogel Microcapsules Functionalized with Au Nanoparticles or Au Nanorods

Microcapsules consisting of hydrogel shells cross-linked by glucosamine-boronate ester complexes and duplex nucleic acids, loaded with dyes or drugs and functionalized with Au nanoparticles (Au NPs) or Au nanorods (Au NRs), are developed. Irradiation of Au NPs or Au NRs results in the thermoplasmonic heating of the microcapsules, and the dissociation of the nucleic acid cross-linkers. The separation of duplex nucleic acid cross-linkers leads to low-stiffness hydrogel shells, allowing the release of loads. Switching off the light-induced plasmonic heating results in the regeneration of stiff hydrogel shells protecting the microcapsules, leading to the blockage of release processes. The thermoplasmonic release of tetramethylrhodamine-dextran, Texas Red-dextran, doxorubicin-dextran (DOX-D), or camptothecin-carboxymethylcellulose (CPT-CMC) from the microcapsules is introduced. By loading the microcapsules with two different drugs (DOX-D and CPT-CMC), the light-controlled dose release is demonstrated. Cellular experiments show efficient permeation of Au NPs/DOX-D or Au NRs/DOX-D microcapsules into MDA-MB-231 cancer cells and inefficient uptake by MCF-10A epithelial breast cells. Cytotoxicity experiments reveal selective thermoplasmon-induced cytotoxicity of the microcapsules toward MDA-MB-231 cancer cells as compared to MCF-10A cells. Also, selective cytotoxicity towards MDA-MB-231 cancer cells upon irradiation of the Au NPs- and Au NRs-functionalized microcapsules at λ = 532 or 910 nm is demonstrated.

Self-healing biomaterials: The next generation is nano

The U.S. Agency for Healthcare Research and Quality estimates that there are over 1 million total hip and total knee replacements each year in the U.S. alone. Twenty five percent of those implants will experience aseptic loosening, and bone cement failure is an important part of this. Bone cements are based on poly(methyl methacrylate) (PMMA) systems that are strong but brittle polymers. PMMA-based materials are also essential to modern dental fillings, and likewise, the failure rates are high with lifetimes of 3-10 years. These brittle polymers are an obvious target for self-healing systems which could reduce revision surgeries and visits to dentist. Self-healing polymers have been described in the literature since 1996 and examples from Roman times are known, but their application in medicine has been challenging. This review looks at the development of self-healing biomaterials for these applications and the challenges that lie between development and the clinic. Many of the most promising formulations involve introducing nanoscale components which offer substantial potential benefits over their microscale counterparts especially in composite systems. There is substantial promise for translation, but issues with toxicity, robustness, and reproducibility of these materials in the complex environment of the body must be addressed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

Triggered Release of Loads from Microcapsule-in-Microcapsule Hydrogel Microcarriers: En-Route to an "Artificial Pancreas"

A method to assemble stimuli-responsive nucleic acid-based hydrogel-stabilized microcapsule-in-microcapsule systems is introduced. An inner aqueous compartment stabilized by a stimuli-responsive hydrogel-layer (∼150 nm) provides the inner microcapsule (diameter ∼2.5 μm). The inner microcapsule is separated from an outer aqueous compartment stabilized by an outer stimuli-responsive hydrogel layer (thickness of ∼150 nm) that yields the microcapsule-in-microcapsule system. Different loads, e.g., tetramethyl rhodamine-dextran (TMR-D) and CdSe/ZnS quantum dots (QDs), are loaded in the inner and outer aqueous compartments. The hydrogel layers exist in a higher stiffness state that prevents inter-reservoir or leakage of the loads from the respective aqueous compartments. Subjecting the inner hydrogel layer to Zn2+-ions and/or the outer hydrogel layer to acidic pH or crown ether leads to the triggered separation of the bridging units associated with the respective hydrogel layers. This results in the hydrogel layers of lower stiffness allowing either the mixing of the loads occupying the two aqueous compartments, the guided release of the load from the outer aqueous compartment, or the release of the loads from the two aqueous compartments. In addition, a pH-responsive microcapsule-in-microcapsule system is loaded with glucose oxidase (GOx) in the inner aqueous compartment and insulin in the outer aqueous compartment. Glucose permeates across the two hydrogel layers resulting in the GOx catalyzed aerobic oxidation of glucose to gluconic acid. The acidification of the microcapsule-in-microcapsule system leads to the triggered unlocking of the outer, pH-responsive hydrogel layer and to the release of insulin. The pH-stimulated release of insulin is controlled by the concentration of glucose. While at normal glucose levels, the release of insulin is practically prohibited, the dose-controlled release of insulin in the entire diabetic range  is demonstrated. Also, switchable ON/OFF release of insulin is achieved highlighting an autonomous glucose-responsive microdevice operating as an "artificial pancreas" for the release of insulin.

Design of Multifunctional Fluorescent Hybrid Materials Based on SiO2 Materials and Core-Shell Fe3 O4 @SiO2 Nanoparticles for Metal Ion Sensing

Hybrid fluorescent materials constructed from organic chelating fluorescent probes and inorganic solid supports by covalent interactions are a special type of hybrid sensing platform that has gained much interest in the context of metal ion sensing applications owing to their excellent advantages, recyclability, and solubility/dispersibility in particular, as compared with single organic fluorescent molecules. In recent decades, SiO₂ materials and core-shell Fe₃ O₄ @SiO₂ nanoparticles have become important inorganic solid materials and have been used as inorganic solid supports to hybridize with organic fluorescent receptors, resulting in multifunctional fluorescent hybrid systems for potential applications in sensing and related research fields. Therefore, recent progress in various fluorescent-group-functionalized SiO₂ materials is reviewed, with a focus on mesoporous silica nanoparticles and core-shell Fe₃ O₄ @SiO₂ nanoparticles, as interesting fluorescent organic-inorganic hybrid materials for sensing applications toward essential and toxic metal ions. Selective examples of other types of silica/silicon materials, such as periodic mesoporous organosilicas, solid SiO₂ nanoparticles, fibrous silica spheres, silica nanowires, silica nanotubes, and silica hollow microspheres, are also mentioned. Finally, relevant perspectives of metal-ion-sensing-oriented silica-fluorescent probe hybrid materials are provided.

Dual-functional supramolecular nanohybrids of quantum dot/biopolymer/chemotherapeutic drug for bioimaging and killing brain cancer cells in vitro

Glioblastoma (GBM) is the utmost aggressive and lethal primary brain cancer, which has a poor prognosis and remains virtually incurable. Nanomedicine with emerging disruptive nanotechnology alternatives, including designed supramolecular nanohybrids has excellent potential as multimodal tools against cancer by combining nanomaterials, biomacromolecules, and drugs. Thus, we developed and constructed for the first time quantum dot-biopolymer-drug nanohybrids based on host-guest chemistry for simultaneous bioimaging, targeting, and anti-cancer drug delivery against GBM cells in vitro. ZnS fluorescent quantum dots (ZnS-QDs) were produced using chemically modified polysaccharide, carboxymethylcellulose (CMC), as water-soluble capping ligand and biofunctional layer via a facile one-step eco-friendly aqueous colloidal process at room temperature and physiological pH. These hybrid inorganic-organic nanocolloids (ZnS@CMC) were electrostatically conjugated with doxorubicin (DOX) anti-cancer drug forming innovative supramolecular complexes (ZnS@CMC-DOX) for amalgamating bioimaging and killing cancer cells. These nanoconjugates were characterized regarding their optical and physicochemical properties combined with morphological and structural features. The cytocompatibility was evaluated by MTT assay using healthy and GBM cells. The results showed that ultra-small ZnS-QDs were expertly produced uniform nanocolloids (average size = 3.6 nm). They demonstrated photoluminescence emission within the visible range of spectra. The cell viability results in vitro showed no cytotoxicity of ZnS@CMC nanohybrids towards both cell types. In summary, the novelty of this research relies on using a nanotheranostic strategy for developing ZnS@CMC-DOX nanohybrids with supramolecular vesicle-like structures. They behaved simultaneously as active fluorescent nanoprobes and nanocarriers with modulated drug release for bioimaging and killing malignant glioma cells proving the high potential for applications in cancer nanomedicine.

Blue- and green-emitting hydrophobic carbon dots: preparation, optical transition, and carbon dot-loading

In the past decade, hydrophobic fluorescent carbon dots (OCDs) have received little attention, and its potential application and light transition mechanism is seldom explored. Here we report a novel one-step approach for synthesizing blue- and green-emitting hydrophobic fluorescent carbon dots (OCD_b and OCD_g) by calcinating with the uses of citric acid and hexadecylamine as initial reactants. The optimal conditions for preparing OCD_b and OCD_g were obtained by using the Taguchi L25 (3⁵) orthogonal array. The highest quantum yield and product yield of OCDs reached 80.2% and 57.1%, respectively, larger than those from most of all the known reports. The fluorescent stability of OCD_b and OCD_g was excellent under UV irradiation (30 W) for days. The luminescent color of OCDs showed a great dependence on reaction conditions. It is easier to get OCD_g via a reaction kept at a high temperature for a long time. The optical transition mechanism was studied for the two kinds of color OCDs, and therefore proposed in combination with their optical properties and surface groups. The reason for light transition is probably related to an appropriate critical ratio and surface density of the C=O and N-H bond in the surface structure of the product. For the OCD_g, the concentration matching ratio of N-H and C=O bonds in the surface structure of the green-emitting product is approximately between d/2 and 3d/2, where d is a fixed constant. Lower than or higher than this critical ratio range, the product emits blue light. Based on their high fluorescence quantum efficiency and the advantages mentioned above, these OCDs were then respectively used for preparing hydrophobic fluorescent carbon dot-loading liposomes and acrylate films, both exhibiting a perfect performance with no fluorescence quenching.

Organic/inorganic nanohybrids as multifunctional gene delivery systems

In this review, we summarize the rational design and versatile application of organic/inorganic hybrid gene carriers as multifunctional delivery systems. Organic/inorganic nanohybrids with both organic and inorganic components in one nanoparticle have attracted intense attention because of their favorable properties. Particularly, nanohybrids comprising cationic polymers and inorganic nanoparticles are considered to be promising candidates as multifunctional gene delivery systems. In this review, we begin with an introduction of gene delivery and gene carriers to demonstrate the incentive for fabricating nanohybrids as multifunctional carriers. Next, the construction strategies and morphology effects of organic/inorganic hybrid gene carriers are summarized and discussed. Both sections provide valuable information for the design and synthesis of hybrid gene carriers with superior properties. Finally, an overview is provided of the application of nanohybrids as multifunctional gene carriers. Diverse therapies and versatile imaging-guided therapies have been achieved via the rational design of nanohybrids. In addition to a simple combination of the functions of organic and inorganic components, the performances arising from the synergistic effects of both components are considered to be more intriguing. In summary, this review might offer guidance for the understanding of organic/inorganic nanohybrids as multifunctional gene delivery systems.

MOF-Based Nanotubes to Hollow Nanospheres through Protein-Induced Soft-Templating Pathways

A controllable and facile strategy is established for constructing metal-organic frameworks-based (MOF-based) hollow composites via a protein-induced soft-templating pathway. Using metal-sodium deoxycholate hydrogel as soft-template, nanotubes are gained while the protein is absent. With the presence of protein, hollow nanospheres structure are prepared by changing the amount of protein. To verify the universality of the proposed pathway, two kinds of proteins (Burkholderia cepacia lipase and penicillin G acylase) and three kinds of MOF (ZIF-8, ZIF-67, and Fe-MOF) are adopted as model proteins and materials, and the obtained protein-containing composites (named protein@H-MOF) possess high bioactivity and stability. This proposed strategy provides a facile method for preparing MOF-based composites under mild conditions, facilitating the applications of MOF in the fields of biocatalyst construction, biomolecule encapsulation, and drug delivery.

Preparation of Prussian Blue Containing Polymeric Nanocapsule via Interfacial Confined Coordination in Crosslinked Inverse Miniemulsion

This work presents a simple and facile strategy for the creation of Prussian blue containing polymeric nanocapsules. An crosslinked inverse miniemulsion with a formula of water/ K₄Fe(CN)₆/1,2-bis-(-2-iodoethyl) ethane(BIEE)/ toluene/ PDMAEMA-b-PS stabilizer mixture was prepared as soft template firstly. A crosslinking nanocapsule structure with K₄Fe(CN)₆ in water core could be achieved by a crosslinking reaction between PDMAEMA-b-PS stabilizers and BIEE. Upon the following addition of FeCl₃ ether solution into the oil phase of this inverse miniemulsion, a coordination reaction between two iron salts occurred immediately to form a Prussian blue complex. Due to the solubility limitation of FeCl₃ in the oil phase of the miniemulsion, forcing the coordination reaction of K₄Fe(CN)₆ and FeCl₃ mainly occurred at the oil-water interface of the nanocapsules, resulting in a soft polymer/Prussian blue(PB) hybrid nanocapsule.

Nano-, micro-, and macroscale drug delivery systems for cancer immunotherapy

Immunotherapy is moving to the frontier of cancer treatment. Drug delivery systems (DDSs) have greatly advanced the development of cancer immunotherapeutic regimen and combination treatment. DDSs can spatiotemporally present tumor antigens, drugs, immunostimulatory molecules, or adjuvants, thus enabling the modulation of immune cells including dendritic cells (DCs) or T-cells directly in vivo and thereby provoking robust antitumor immune responses. Cancer vaccines, immune checkpoint blockade, and adoptive cell transfer have shown promising therapeutic efficiency in clinic, and the incorporation of DDSs may further increase antitumor efficiency while decreasing adverse side effects. This review focuses on the use of nano-, micro-, and macroscale DDSs for co-delivery of different immunostimulatory factors to reprogram the immune system to combat cancer. Regarding to nanoparticle-based DDSs, we emphasize the nanoparticle-based tumor immune environment modulation or as an addition to gene therapy, photodynamic therapy, or photothermal therapy. For microparticle or capsule-based DDSs, an overview of the carrier type, fabrication approach, and co-delivery of tumor vaccines and adjuvants is introduced. Finally, macroscale DDSs including hydrogels and scaffolds are also included and their role in personalized vaccine delivery and adoptive cell transfer therapy are described. Perspective and clinical translation of DDS-based cancer immunotherapy is also discussed. We believe that DDSs hold great potential in advancing the fundamental research and clinical translation of cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Immunotherapy is moving to the frontier of cancer treatment. Drug delivery systems (DDSs) have greatly advanced the development of cancer immunotherapeutic regimen and combination treatment. In this comprehensive review, we focus on the use of nano-, micro-, and macroscale DDSs for the co-delivery of different immunostimulatory factors to reprogram the immune system to combat cancer. We also propose the perspective on the development of next-generation DDS-based cancer immunotherapy. This review indicates that DDSs can augment the antitumor T-cell immunity and hold great potential in advancing the fundamental research and clinical translation of cancer immunotherapy by simultaneously delivering dual or multiple immunostimulatory drugs.

Microfluidic preparation of monodisperse polymeric microspheres coated with silica nanoparticles

The synthesis of organic-inorganic hybrid particles with highly controlled particle sizes in the micrometer range is a major challenge in many areas of research. Conventional methods are limited for nanometer-scale fabrication because of the difficulty in controlling the size. In this study, we present a microfluidic method for the preparation of organic-inorganic hybrid microparticles with poly (1,10-decanediol dimethacrylate-co-trimethoxysillyl propyl methacrylate) (P (DDMA-co-TPM)) as the core and silica nanoparticles as the shell. In this approach, the droplet-based microfluidic method combined with in situ photopolymerization produces highly monodisperse organic microparticles of P (DDMA-co-TPM) in a simple manner, and the silica nanoparticles gradually grow on the surface of the microparticles prepared via hydrolysis and condensation of tetraethoxysilane (TEOS) in a basic ammonium hydroxide medium without additional surface treatment. This approach leads to a reduction in the number of processes and allows drastically improved size uniformity compared to conventional methods. The morphology, composition, and structure of the hybrid microparticles are analyzed by SEM, TEM, FT-IR, EDS, and XPS, respectively. The results indicate the inorganic shell of the hybrid particles consists of SiO2 nanoparticles of approximately 60 nm. Finally, we experimentally describe the formation mechanism of a silica-coating layer on the organic surface of polymeric core particles.

Advances in Magnetic Nanoparticles for Biomedical Applications

Magnetic nanoparticles (NPs) are emerging as an important class of biomedical functional nanomaterials in areas such as hyperthermia, drug release, tissue engineering, theranostic, and lab-on-a-chip, due to their exclusive chemical and physical properties. Although some works can be found reviewing the main application of magnetic NPs in the area of biomedical engineering, recent and intense progress on magnetic nanoparticle research, from synthesis to surface functionalization strategies, demands for a work that includes, summarizes, and debates current directions and ongoing advancements in this research field. Thus, the present work addresses the structure, synthesis, properties, and the incorporation of magnetic NPs in nanocomposites, highlighting the most relevant effects of the synthesis on the magnetic and structural properties of the magnetic NPs and how these effects limit their utilization in the biomedical area. Furthermore, this review next focuses on the application of magnetic NPs on the biomedical field. Finally, a discussion of the main challenges and an outlook of the future developments in the use of magnetic NPs for advanced biomedical applications are critically provided.

Design and Construction of Hybrid Microcapsules with Higher-Order Structure and Multiple Functions

The construction of inorganic-protein hybrid microcapsules by using bovine serum albumin, metal ion clusters, and poly (N-isopropylacrylamide) nanoconjugates as building blocks is presented. These microcapsules have robust membranes, which can keep their spherical morphology. They support interfacial catalytic activity by the ion clusters on their surface, and can be used as a platform to immobilize enzyme on the interface of oil/water to increase the diversity and efficiency of catalysis. These microcapsules also act as a container to make materials away from bacteria when existing silver clusters on the membrane. The obtained results highlight the construction of these microcompartments. These novel microcompartments can provide some new opportunities in bottom-up synthetic biology, bioinspired microstorage/ microreactor, and drug/gene delivery in the future.

POSS-enhanced thermosensitive hybrid hydrogels for cell adhesion and detachment

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)-based substrates have presented great promise in cell sheet engineering. However, non-functionalized PNIPAM cannot be well applied for cell cultivation, due to the low cell adhesion. Herein, to enhance PNIPAM-based substrates and to promote cell proliferation and detachment, a polyhedral oligomeric silsesquioxane (POSS) nanoscale inorganic enhanced agent has been introduced into PNIPAM matrices to construct POSS-containing hybrid hydrogels. The hydrogels were facilely prepared using POSS as a cross-linker via one-pot crosslinking reaction under UV irradiation. The swelling behavior, thermal stability and the mechanical properties of POSS–PNIPAM hybrid hydrogels have been evaluated and they are all dependent on the content of POSS. The in vitro experiment confirms that human amniotic mesenchymal stem cells (hAMSCs) exhibit clearly enhanced adhesion and proliferation on the substrates of POSS–PNIPAM hybrid hydrogels in comparison to the pure PNIPAM hydrogel without POSS. Based on the thermal-responsiveness of PNIPAM, the proliferated cells are easily released without damage from the surface of hybrid hydrogels. Therefore, POSS-enhanced PNIPAM hybrid hydrogels provide a unique approach for harvesting anchorage dependent stem cells.

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)-based substrates have presented great promise in cell sheet engineering.

Preparation and application of flavor and fragrance capsules

The preparation methods and applications of flavor and fragrance capsules based on polymeric, inorganic and polymeric–inorganic wall materials are summarized.

Pollen-like ZIF-8 colloidosomesviaemulsion templating and etching

We report a one-pot emulsion-templating and post-synthetic etching strategy for the preparation of hierarchically structured ZIF-8 microcapsules.

Janus Reactors with Highly Efficient Enzymatic CO2 Nanocascade at Air-Liquid Interface

Though enzymatic cascade reactors have been the subject of intense research over the past few years, their application is still limited by the complicated fabrication protocols, unsatisfactory stability and lack of effective reactor designs. In addition, the spatial positioning of the cascade reactor has so far not been investigated, which is of significant importance for biphase catalytic reaction systems. Inspired by the Janus properties of the lipid cellular membrane, here we show a highly efficient Janus gas-liquid reactor for CO₂ hydration and conversion. Within the Janus reactor, nanocascades containing the nanoscale compartmentalized carbonic anhydrase and formic dehydrogenase were positioned at a well-defined gas-liquid interface, with a high substrate concentration gradient. The Janus reactor exhibited 2.5 times higher CO₂ hydration efficiency compared with the conventional gas-liquid contactor with pristine membranes, and the formic acid conversion rate can reach approximately 90%. Through this work, we provide evidence that the spatial arrangement of the nanocascade is also crucial to efficient reactions, and the Janus reactor can be a promising candidate for the biphase catalytic reactions in environmental, biological and energy aspects.