Chiral Core–Shell Upconversion Nanoparticle@MOF Nanoassemblies for Quantification and Bioimaging of Reactive Oxygen Species in Vivo

Electrochemiluminescence sensor based on upconversion nanoparticles and Zr-based porphyrinic metal-organic frameworks with recognition sites for mercaptan detection

In light of the critical necessity for precise detection of mercaptan in gasoline, due to its potential to induce metal corrosion and catalyst poisoning, this study investigates a novel methodology that employs resonance energy transfer (RET) between upconversion nanoparticles (UCNPs) and zirconium-based porphyrinic metal-organic frameworks (MOFs) to develop a highly sensitive and selective electrochemiluminescence (ECL) sensor. The NaYF4: Yb3+, Er3+@NaYF4@MOFs nanocomposite has been thoroughly characterized and exhibits enhanced ECL emission. This enhancement is attributed to the efficient RET between the UV-vis absorption of the Zr-based porphyrinic MOFs and the upconversion luminescence emission of the UCNPs. Upon interaction with mercaptan, the ECL signal experiences a significant decrease due to the interaction between mercaptan and Zr-based porphyrinic MOFs, leading to the quenching of the ECL signal. This phenomenon facilitates the sensitive detection of mercaptan within a linear range of 0.5 mg/L to 200 mg/L, with a low detection limit of 0.054 mg/L. The sensor demonstrates high selectivity and excellent stability, making it a promising tool for the quality control and environmental monitoring of mercaptan in gasoline.

Water-Stable MIL-MOFs Developed Through a Novel Sacrifice-Protection Strategy Inspired by Butterfly Wings' Scales for Long-Term Turn-On Fluorescence Sensing of H2S

Metal-organic frameworks, which are the desired candidates for biosensing application due to their tunable properties, are significantly hindered by their rapid degradation in aqueous solutions, as well as the loss of their inherent fluorescence. Most studies aim to improve the hydrophobicity of materials by modifying their contact angle, thereby enhancing water stability. However, water droplets poorly adhere to the surface of hydrophobic materials, limiting their application for direct contact and detection in aqueous environments. Drawing inspiration from the sacrificial protection mechanism of butterfly wings used to evade predation and entanglement, a universal approach is successfully developed to protect water-sensitive MIL-MOFs from water molecule attack while preserving good hydrophilicity. Using the organic ligand 2,2'-bipyridine-5,5'-dicarboxylic acid (bpydc) as sacrificial protection scales, the MIL-125-NH2-bpydc demonstrated broad pH structural stability (pH 2-12) and fluorescence stability increased by 10.17 time in aqueous solutions, achieving the highest performance in MILMOFs. The MIL-125-NH2-bpydc is biocompatible enabling it to perform long-term fluorescence imaging in living cells and zebrafish, further detecting hydrogen sulfide (H2S) in the aqueous and biological systems via turn-on fluorescence emission. This study offers a novel and universal sacrifice-protection strategy for the design and development of the luminescent biocompatible MOFs tailored for biosensing applications.

Biologically logic-gated Trojan-horse strategy for personalized triple-negative breast cancer precise therapy by selective ferroptosis and STING pathway provoking

Amidst the therapeutic quandaries associated with triple-negative breast cancer (TNBC), an aggressive malignancy distinguished by its immune resistance and limited treatment avenues, the urgent need for innovative solutions is underscored. To conquer the dilemma, we present a groundbreaking approach that ingeniously employs DNA-fragments-containing exosomes (DNA-Exo) and the concept of "biological logic-gates" to achieve precise homing and controlled selective activation of ferroptosis and stimulator interferon genes (STING) pathways. Leveraging insights from our previous research, a nano-Trojan-horse, Fe0@HMON@DNA-Exo, is engineered via in situ Fe0 synthesis within the glutathione (GSH)-responsiveness degradable hollow mesoporous organosilica nanoparticles (HMON) and subsequently enveloped in DNA-Exo derived from 7-ethyl-10-hydroxycamptothecin (SN38)-treated 4T1 cells. Emphasizing the precision of our approach, the DNA-Exo ensures specific 'homing' to TNBC cells, rendering a targeted delivery mechanism. Concurrently, the concept of "biological logic-gates" is employed to dictate a meticulous and selective activation of STING in antigen-presenting cells (APCs) under OR logic-gating with robust immune response and Fe0-based ferroptosis in TNBC cells under AND logic-gating with reactive oxygen species (ROS) storm generation. In essence, our strategy exhibits great potential in transforming the "immunologically cold" nature of TNBC, enabling precise control over cellular responses, illuminating a promising therapeutic paradigm that is comprehensive and productive in pursuing precision oncology and paving the way for personalized TNBC therapies.

Laser-assisted thermoelectric-enhanced hydrogen peroxide biosensors based on Ag2Se nanofilms for sensitive detection of bacterial pathogens

Thermoelectric (TE) materials can convert the heat produced during biochemical reactions into electrical signals, enabling the self-powered detection of biomarkers. In this work, we design and fabricate a simple Ag2Se nanofilm-based TE biosensor to precisely quantify hydrogen peroxide (H2O2) levels in liquid samples. A chemical reaction involving horseradish peroxidase, ABTS and H2O2 in the specimens produces a photothermal agent-ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) free radical, which triggers the heat fluctuations at the TE sensor through the photo-thermal effect, eventually enabling the sensing of H2O2. Consequently, the constructed sensor can achieve a detection limit of 0.26 μM by a three-leg TE device design. Further investigations suggest that the application of our TE sensor can be extended in testing H2O2 in beverages (including milk, soda water, and lemonade) and evaluating the load of bacterial pathogens relevant to dental diseases and infections including Streptococcus sanguinis and Methicillin-resistant Staphylococcus aureus with high analytical accuracy. This strategy utilizes the combination of high thermoelectric performance with chemical reactions to realize a straightforward and accurate biomarker detection method, making it suitable for applications in medical diagnostics, personalized health monitoring, and the food industry.

Chiral Inorganic Nanomaterial-Based Diagnosis and Treatments for Neurodegenerative Diseases

Chiral nanomaterials are widely investigated over recent decades due to their biocompatibility and unique chiral effects. These key properties have significantly promoted the rapid development of chiral nanomaterials in bioengineering and medicine. In this review, the basic principles of constructing chiral nanomaterials along with the latest progress in research are comprehensively summarized. Then, the application of chiral nanomaterials for the diagnosis of neurodegenerative diseases (NDDs) is systematically described. In addition, the significant potential and broad prospects of chiral nanomaterials in the treatment of NDDs are highlighted from several aspects, including the disaggregation of neurofibrils, the scavenging of reactive oxygen species, regulation of the microbial-gut-brain axis, the elimination of senescent cells, and the promotion of directed differentiation in neural stem cells. Finally, a perspective of the challenges and future development of chiral nanomaterials for the treatment of NDDs is provided.

Intensive and Persistent Chemiluminescence from Orderly Arranged Ligands within Metal-Organic Frameworks for Inflammation Imaging

Chemiluminescence offers ultrasensitive imaging for the diagnosis of a variety of diseases by removing the interference from excitation light sources. Here, we prepared two chemiluminescent metal-organic frameworks (Mn-ADA and Zn-ADA) by using (2E,2'E)-3,3'-(anthracene-9,10-diyl)diacrylic acid (ADA) as a ligand. In Mn-ADA and Zn-ADA, the Mn atoms and Zn atoms are six-coordinated and eight-coordinated, respectively, and their frameworks are different in spatial structure. Due to the orderly arrangement of the fluorescence ligands and one-dimensional channel control of the diffusion of the reactant, Mn-ADA exhibits superstrong intensity and persistent chemiluminescence compared to ADA. The intensity of Mn-ADA is 43 times higher, and the lifetime is two times longer than that of ADA. Furthermore, different coordination also causes the chemiluminescence intensity of Mn-ADA to be stronger than that of Zn-ADA. It is established that Mn-ADA can detect H2O2 and image inflammation in mice without the excitation light. This methodology demonstrates the potential of metal-organic frameworks (MOFs) to enhance chemiluminescence and offers a new avenue for the development of MOF materials intended for biomedical application.

Single-Cell Multi-omics Assessment of Spinal Cord Injury Blocking via Cerium-doped Upconversion Antioxidant Nanoenzymes

Spinal cord injury (SCI) impairs the central nervous system and induces the myelin-sheath-deterioration because of reactive oxygen species (ROS), further hindering the recovery of function. Herein, the simultaneously emergency treatment and dynamic luminescence severity assessment (SETLSA) strategy is designed for SCI based on cerium (Ce)-doped upconversion antioxidant nanoenzymes (Ce@UCNP-BCH). Ce@UCNP-BCH can not only efficiently eliminate the SCI localized ROS, but dynamically monitor the oxidative state in the SCI repair process using a ratiometric luminescence signal. Moreover, the classic basso mouse scale score and immunofluorescence analysis together exhibit that Ce@UCNP-BCH effectively facilitates the regeneration of spinal cord including myelin sheath, and promotes the functional recovery of SCI mice. Particularly, the study combines snATAC-eq and snRNA-seq to reveal the heterogeneity of spinal cord tissue following Ce@UCNP-BCH treatment. The findings reveal a significant increase in myelinating oligodendrocytes, as well as higher expression of myelination-related genes, and the study also reveals the gene regulatory dynamics of remyelination after treatment. Besides, the ETLSA strategy synergistically boosts ROS consumption through the superoxide dismutase (SOD)-related pathways after SOD-siRNA treatment. In conclusion, this SETLSA strategy with simultaneously blocking and dynamic monitoring oxidative stress has enriched the toolkit for promoting SCI repair.

Metal-organic framework-based hybrids with photon upconversion

Upconversion materials (UCMs) featuring an anti-Stokes type emission establish them as an important category of photoluminescent materials. Metal-organic frameworks (MOFs) are rapidly gaining prominence as a class of versatile materials with favourable physical and chemical properties, including high porosity, controllable pore size, flexible design, and diverse functional sites. To endow MOFs with upconversion capability and improve the properties and performance of UCMs, the hybrids integrating UCMs and MOFs are proven to be successful. This review focuses on the research advancements of upconverting MOF-based hybrids, encompassing classifications, luminescence mechanisms, designs, properties, and applications in energy, catalysis, and biomedical fields. The analyses on the functions of upconversion and MOFs, as well as the advantages and disadvantages of various upconverting MOF-based hybrids, are included. Future research directions spanning from properties and performance to applications are explored. This review will be valuable in highlighting the research accomplishments, inspiring more ideas, facilitating deeper investigations in diverse avenues, and further advancing the research field.

Upconversion nanoparticles-CuMnO2 nanoassemblies for NIR-excited imaging of reactive oxygen species in vivo

Here, we designed a ratiometric luminescent nanoprobe based on lanthanide-doped upconversion nanoparticles-CuMnO2 nanoassemblies for rapid and sensitive detection of reactive oxygen species (ROS) levels in living cells and mouse. CuMnO2 nanosheets exhibit a wide absorption range of 300-700 nm, overlapping with the visible-light emission of upconversion nanoparticles (UCNPs), resulting in a significant upconversion luminescence quenching. In an acidic environment, H2O2 can promote the redox reaction of CuMnO2, leading to its dissociation from the surface of UCNPs and the restoration of upconversion luminescence. The variation in luminescence intensity ratio (UCL475/UCL450) were monitored to detect ROS levels. The H2O2 nanoprobe exhibited a linear response in the range of 0.314-10 μM with a detection limit of 11.3 nM. The biological tests proved the excellent biocompatibility and low toxicity of obtained UCNPs-CuMnO2 nanoassemblies. This ratiometric luminescent nanoprobe was successfully applied for the detection of exogenous and endogenous ROS in live cells as well as in vivo ROS quantitation. The dual transition metal ions endow this probe efficient catalytic decomposition capabilities, and this sensing strategy broadens the application of UCNPs-based nanomaterials in the field of biological analysis and diagnosis.

Upconversion Nanoparticle-Anchored Metal-Organic Framework Nanostructures for Remote-Controlled Cancer Optogenetic Therapy

Optogenetics, a revolutionary technique utilizing light-sensitive proteins to control cellular functions with high spatiotemporal precision, presents a promising avenue for disease treatment; however, its application in cancer therapy remains constrained by limited research. Herein, we introduce a pioneering strategy for remote-controlled optogenetic cancer therapy, synergistically merging optogenetics with ion therapy, which incorporates ion self-supply, in situ ion channel construction, and near-infrared (NIR) light-activated ion therapy, facilitating remote and noninvasive manipulation of cellular activities in deep tissues and living animals. We report the facile synthesis of water-dispersible upconversion nanoparticle (UCNP)-metal-organic framework (MOF) nanohybrids capable of effectively delivering plasmid DNA to cancer cells, thereby enabling the in situ expression of photoactivatable cation channels. The pH-responsive MOF components serve as a reservoir for metal cations, which are released in the acidic microenvironment of tumors, while the UCNP components function as remote-controlled transducers, converting near-infrared (NIR) light into visible light to activate the cation channels and allowing the cancer influx of released metal cations for ion therapy. The proposed remote-controlled cancer optogenetic therapy demonstrates its effectiveness across multiple tumor models, including subcutaneous colon tumors, subcutaneous breast tumors, and orthotopic breast tumors. This study represents a significant step toward the realization of optogenetics in clinics, with substantial potential for advancing cancer therapy.

The oxygen puzzle in FLASH radiotherapy: A comprehensive review and experimental outlook

FLASH radiotherapy is attracting increasing interest because it maintains tumor control while inflicting less damage to normal tissues compared to conventional radiotherapy. This sparing effect, the so-called FLASH effect, is achieved when radiation is delivered at ultra-high dose rates (≥40 Gy/s). Although the FLASH effect has already been demonstrated in several preclinical models, a complete mechanistic description explaining why tumors and normal tissues respond differently is still missing. None of the current hypotheses fully explains the experimental evidence. A common point between many of these is the role of oxygen, which is described as a major factor, either through transient hypoxia in the form of dissolved molecules, or reactive oxygen species (ROS). Therefore, this review focuses on both forms of this molecule, retracing old and more recent theories, while proposing new mechanisms that could provide a complete description of the FLASH effect based on preclinical and experimental evidence. In addition, this manuscript describes a set of experiments designed to provide the FLASH community with new tools for exploring the post-irradiation fate of ROS and their potential biological implications.

A Two-Photon-Active Zr-Based Metal-Organic Framework-Based Orthogonal Nanoprobe for Recognition of Cellular Senescence

A luminescent nanoprobe capable of orthogonal sensing of two independent events is highly significant for unbiased disease-related detection such as the detection of senescent cells. Moreover, it is invaluable that the nanoprobe possesses a two-photon excitable characteristic that is highly suitable for imaging living cells and tissues. Herein, we present a two-photon-excitable multiluminescent orthogonal-sensing nanoprobe (OS nanoprobe) capable of detecting both pH elevation and β-galactosidase (β-gal) overexpression in senescent cells. In the design, Zr-based dual-emissive metal-organic frameworks prepared from two mixed amino linkers, referred to as NH2-MU, were used as the component for the ratiometric sensing of pH; additionally, fluorogenic resorufin-β-d-galactopyranoside, linked to the NH2-MU framework, enables β-gal detection. In the OS nanoprobe, the signals for pH and β-gal sensing remain independent while maintaining high colocalization. The two-photon excitable organic linkers of NH2-MU impart the OS nanoprobe with a bioimaging capability, allowing for the differentiation of senescent human foreskin fibroblast (HFF) cells from younger HFF cells or LacZ positive cells with the 800 nm laser excitation. This study marks the first instance of achieving the multiplexed orthogonal fluorescent sensing of cellular senescence using a two-photon excitation strategy, suggesting the potential of using versatile metal-organic framework (MOFs)-based fluorophores to realize the orthogonal multiplexing of disease-related biomarkers through multiphoton excitation.

Bilayer MOF nanomachine for precision breast cancer cell fluorescent imaging and therapy

A bilayer MOF reporter (ZIF-67@FAM-mRNA@ZIF-8) was synthesized, and the ZIF-67 was used as a carrier and fluorescent quencher to connect the FAM reporter through electrostatic adsorption and coordination effect. The ZIF-8 covering the outer layer can improve the stability of the probe and cell permeability, which helps the FAM reporter effectively release. After entering the cancer cells, the acidic environment in the cells induced the decomposition of ZIF-8. The excess ATP in the tumor cells competitively binds ZIF-67, causing the FAM reporter to shed and restore fluorescence. The shed FAM reporter was specifically bound to the overexpressed miRNA-21 in breast cancer cells to achieve fluorescence imaging and therapy of breast cancer. The results of specific imaging and apoptosis experiments of breast cancer cells indicate that bilayer MOF nanomachine provides an effective nanotherapy platform for accurate fluorescence imaging.

Enhanced Enantioselective Discrimination Regulated by Achiral Ligands in Chiral Metal-Organic Frameworks

Enantioselective recognition is a fundamental property of chiral linkers in chiral metal-organic frameworks (CMOFs). However, clarifying the efficient enantioselective discrimination tailored by achiral linkers remains challenging to explain the chiral recognition mechanism and efficiency. Here, two CMOFs ([Zn2(l-Phe)2(bpa)2]n and [Zn2(l-Phe)2(bpe)2]n) with the completely different enantioselective recognition are synthesized from different nonchiral ligands and the same chiral ligands. The enantioselective recognition of CMOF is undoubtedly related to l-Phe, which differs in the hydrogen bonding to the Trp enantiomer. However, the electrochemical signals are weak and undifferentiated. [Zn2(l-Phe)2(bpe)2]n produces a flattened coplanar conformation with the -C═C- tether in the achiral ligand. The flattened achiral bpee ligand and its surrounding chiral phenylalanine molecules interact through multiple π-π stacking and hydrogen bonding, which together create a chiral sensor that facilitates the recognition of l-Trp. However, [Zn2(l-Phe)2(bpa)2]n produces a stepped conformation due to the -C-C- tether in the achiral ligand; despite the recognition effect of bpea, the recognition is unsatisfactory. Therefore, the chiral recognition of the two CMOFs stems from the synergistic effect between chiral and achiral ligands. This work shows that nonchiral ligands are also crucial in determining enantiomeric discrimination and opens up a new avenue for designing chiral materials.

Upconversion-based chiral nanoprobe for highly selective dual-mode sensing and bioimaging of hydrogen sulfide in vitro and in vivo

Chiral assemblies have become one of the most active research areas due to their versatility, playing an increasingly important role in bio-detection, imaging and therapy. In this work, chiral UCNPs/CuxOS@ZIF nanoprobes are prepared by encapsulating upconversion nanoparticles (UCNPs) and CuxOS nanoparticles (NPs) into zeolitic imidazolate framework-8 (ZIF-8). The novel excited-state energy distribution-modulated upconversion nanostructure (NaYbF4@NaYF4: Yb, Er) is selected as the fluorescence source and energy donor for highly efficient fluorescence resonance energy transfer (FRET). CuxOS NP is employed as chiral source and energy acceptor to quench upconversion luminescence (UCL) and provide circular dichroism (CD) signal. Utilizing the natural adsorption and sorting advantages of ZIF-8, the designed nanoprobe can isolate the influence of other common disruptors, thus achieve ultra-sensitive and highly selective UCL/CD dual-mode quantification of H2S in aqueous solution and in living cells. Notably, the nanoprobe is also capable of in vivo intra-tumoral H2S tracking. Our work highlights the multifunctional properties of chiral nanocomposites in sensing and opens a new vision and idea for the preparation and application of chiral nanomaterials in biomedical and biological analysis.

Chirality-Dependent Reprogramming of Macrophages

The chirality of materials directly influences their transport and biological effects in physiological conditions. However, the impact of chiral materials on cellular metabolic reprogramming remains incompletely elucidated. In this study, we have synthesized chiral gold particles through a light-driven particle growth approach and demonstrated that d-Au particles exhibited superior macrophage activation ability compared to l-Au particles. An inflammatory creatine-phosphocreatine shunt was induced following d-Au stimulation. This shunt, facilitated by the upregulated expression of creatine kinase muscle-type (CKM), also resulted in a reduction in cytosolic levels of creatine. Pharmacological inhibition and genetic ablation of CKM further suppressed the secretion of pro-inflammatory cytokines, without compromising mitochondrial respiration. Moreover, the activation of macrophages induced by d-Au was mediated through the activation of the NF-κB and NLRP3 inflammasome pathways. Inhibition of CKM expression not only decreased the secretion of CXCL2 but also attenuated IL-1β by suppressing the NLRP3 inflammasome pathways. Our investigation into the metabolic reprogramming mechanism of chiral materials on macrophage activation is pivotal for the application of chiral-based anticancer therapies.

MRI-Guided Tumor Therapy Based on Synergy of Ferroptosis, Immunosuppression Reversal and Disulfidptosis

Triple negative breast cancer (TNBC) cells have a high demand for oxygen and glucose to fuel their growth and spread, shaping the tumor microenvironment (TME) that can lead to a weakened immune system by hypoxia and increased risk of metastasis. To disrupt this vicious circle and improve cancer therapeutic efficacy, a strategy is proposed with the synergy of ferroptosis, immunosuppression reversal and disulfidptosis. An intelligent nanomedicine GOx-IA@HMON@IO is successfully developed to realize this strategy. The Fe release behaviors indicate the glutathione (GSH)-responsive degradation of HMON. The results of titanium sulfate assay, electron spin resonance (ESR) spectra, 5,5'-Dithiobis-(2-nitrobenzoic acid (DTNB) assay and T1-weighted magnetic resonance imaging (MRI) demonstrate the mechanism of the intelligent iron atom (IA)-based cascade reactions for GOx-IA@HMON@IO, generating robust reactive oxygen species (ROS). The results on cells and mice reinforce the synergistic mechanisms of ferroptosis, immunosuppression reversal and disulfidptosis triggered by the GOx-IA@HMON@IO with the following steps: 1) GSH peroxidase 4 (GPX4) depletion by disulfidptosis; 2) IA-based cascade reactions; 3) tumor hypoxia reversal; 4) immunosuppression reversal; 5) GPX4 depletion by immunotherapy. Based on the synergistic mechanisms of ferroptosis, immunosuppression reversal and disulfidptosis, the intelligent nanomedicine GOx-IA@HMON@IO can be used for MRI-guided tumor therapy with excellent biocompatibility and safety.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)-Sensitive Triggers

Reactive oxygen species (ROS) are critical for cellular signaling. Various pathophysiological conditions are also associated with elevated levels of ROS. Hence, ROS-sensitive triggers have been extensively used for selective payload delivery. Such applications are predicated on two key functions: (1) a sufficient magnitude of concentration difference for the interested ROS between normal tissue/cells and intended sites and (2) appropriate reaction kinetics to ensure a sufficient level of selectivity for payload release. Further, ROS refers to a group of species with varying reactivity, which should not be viewed as a uniform group. In this review, we critically analyze data on the concentrations of different ROS species under various pathophysiological conditions and examine how reaction kinetics affect the success of ROS-sensitive linker chemistry. Further, we discuss different ROS linker chemistry in the context of their applications in drug delivery and imaging. This review brings new insights into research in ROS-triggered delivery, highlights factors to consider in maximizing the chance for success and discusses pitfalls to avoid.

Heteroepitaxial Growth to Construct Hexagonal/Hexagonal β-NaYF4:Yb,Tm/Cs4PbBr6 Multi-Code Emitting Core/Shell Nanocrystals

Synthesis of upconversion nanoparticles (UCNPs)-metal halide perovskites (MHPs) heterostructure is garnered immense attentions due to their unparalleled photophysical properties. However, the obvious difference in their structural forms makes it a huge challenge. Herein, hexagonal β-NaYF4 and hexagonal Cs4PbBr6 are filtrated to construct the UCNP/MHP heterostructural luminescent material. The similarity in their crystal structures facilitate the heteroepitaxial growth of Cs4PbBr6 on the surface of β-NaYF4 NPs, leading to the formation of high-quality β-NaYF4:Yb,Tm/Cs4PbBr6 core/shell nanocrystals (NCs). Interestingly, this heterostructure endows the core/shell NCs with typically narrow-band green emission centered at 524 nm under 980 nm excitation, which should be attributed to the Förster resonance energy transfer (FRET) from Tm3+ to Cs4PbBr6. It is noteworthy that the FRET efficiency of β-NaYF4:Yb,Tm/Cs4PbBr6 core/shell NCs (58.33%) is much higher than that of the physically mixed sample (1.84%). In addition, the reduced defect density, lattice anchoring effect, as well as diluted ionic bonding proportion induced by the core/shell structure further increase the excellent water-resistance and thermal cycling stability of Cs4PbBr6. These findings open up a new way to construct UCNP/MHP heterostructure with better multi-code luminescence performance and stability and promote its wide optoelectronic applications.

Modulation by Co (II) Ion of Optical Activities of L/D-glutathione (GSH)-modified Chiral Copper Nanoclusters for Sensitive Adenosine Triphosphate Detection

Chiral nanoscale enantiomers exhibit different biological effects in living systems. However, their chirality effect on the detection sensitivity for chiral biological targets still needs to be explored. Here, we discovered that Co2+ can modulate the luminescence performance of L/D-glutathione (GSH)-modified copper nanoclusters (L/D-Cu NCs) and induce strong chiroptical activities as the asymmetric factor was enhanced 223-fold with their distribution regulating from the ultraviolet to visible region. One Co2+ coordinated with two GSH molecules that modified on the surface of Cu NCs in the way of CoN2O2. On this basis, dual-modal chiral and luminescent signals of Co2+ coordinated L/D-Cu NCs (L/D-Co-Cu NCs) were used to detect the chiral adenosine triphosphate (ATP) based on the competitive interaction between surficial GSH and ATP molecules with Co2+. The limits of detection of ATP obtained with fluorescence and circular dichroism intensity were 9.15 μM and 15.75 nM for L-Co-Cu NCs, and 5.35 μM and 4.69 nM for D-Co-Cu NCs. This demonstrated that selecting suitable chiral configurations of nanoprobes effectively enhances detection sensitivity. This study presents not only a novel method to modulate and enhance the chiroptical activity of nanomaterials but also a unique perspective of chirality effects on the detection performances for bio-targets.

Aggregation-Enabled Electrochemistry in Confined Nanopore Capable of Complementary Faradaic and Non-Faradaic Detection

Electrochemistry that empowers innovative nanoscopic analysis has long been pursued. Here, the concept of aggregation-enabled electrochemistry (AEE) in a confined nanopore is proposed and devised by reactive oxygen species (ROS)-responsive aggregation of CdS quantum dots (QDs) within a functional nanopipette. Complementary Faradaic and non-Faradaic operations of the CdS QDs aggregate could be conducted to simultaneously induce the signal-on of the photocurrents and the signal-off of the ionic signals. Such a rationale permits the cross-checking of the mutually corroborated signals and thus delivers more reliable results for single-cell ROS analysis. Combined with the rich biomatter-light interplay, the concept of AEE can be extended to other stimuli-responsive aggregations for electrochemical innovations.

Tri-mode Responses to Reactive Oxygen Species In Vivo by Chiral Vanadium-Based Nanoparticles

Reactive oxygen species (ROS) are closely associated with the redox balance of the physiological environment, and monitoring ROS can aid in the early diagnosis of many diseases, including cancer. In this study, chiral vanadium trioxide/vanadium nitride (V2O3/VN) nanoparticles (NPs) modified with an organic dye (cyanine 3 [Cy3]) were prepared for ROS sensing. Chiral V2O3/VN NPs were prepared with the "ligand-induced chirality" strategy and showed a g-factor of up to 0.12 at a wavelength of 512 nm. To the best of our knowledge, this g-factor is the highest value of all chiral ceramic nanomaterials. The very high g-factor of the nanoprobe confers very high sensitivity, because the higher g-factor, the higher sensitivity. In the presence of ROS, V3+ in the chiral V2O3/VN nanoprobe undergoes a redox reaction to form V2O5, reducing the circular dichroism and absorbance signals, whereas the fluorescence signal of Cy3 is restored. With this nanoprobe, the limits of detection for the circular dichroic and fluorescence signals in living cells are 0.0045 nmol/106 and 0.018 nmol/106 cells, respectively. This chiral nanoprobe can also monitor ROS levels in vivo by fluorescence. This strategy provides an innovative approach to the detection of ROS and is expected to promote the wider application of chiral nanomaterials for biosensing.

Zeolitic Imidazolate-Framework-Engineered Heterointerface Catalysis for the Construction of Plant-Wearable Sensors

Plant-wearable sensors provide real-time information that enables pesticide inputs to be finely tuned and play critical roles in precision agriculture. However, tracking pesticide information in living plants remains a formidable challenge owing to inadequate shape adaptabilities and low in-field sensor sensitivities. In this study, plant-wearable hydrogel discs are designed by embedding a dual-shelled upconversion-nanoparticles@zeolitic-imidazolate-framework@polydopamine (UCNPs@ZIF@PDA) composite in double-network hydrogels to deliver on-site pesticide-residue information. Benefiting from the enzyme-mimetic catalytic activity of ZIFs and enzyme triggered-responsive property of PDA shell, the hydrogel discs are endowed with high sensing sensitivity toward 2,4-dichlorophenoxyacetic acid pesticide at the nanogram per milliliter level via boosting fluorescence quenching efficiency. Notably, hydrogel discs mounted on tomato plants exhibit sufficient adaptability to profile dynamic pesticide degradation when used in conjunction with an ImageJ processing algorithm, which is practically applicable. Such hydrogel discs form a noninvasive and low-cost toolkit for the on-site acquisition of pesticide information, thereby contributing to the precise management of the health status of a plant and the judicious development of precision agriculture.

Application of metal–organic frameworks in stomatology

Metal–organic frameworks (MOFs), a new class of porous organic–organic hybrid materials controlled by self-assembly of metal atoms and organic pillars, are attracting considerable interest because of their specific properties. More recently, the advantages of different types of nanoscale metal–organic frameworks for the use of MOF nanoparticles in stomatology have been reported in the literature. This article covers the treatment of oral cancer, surface modification of implants, antibacterial dressings, and treatment of periodontitis and periodontal regeneration. It presents recent applications, future challenges, and prospects for MOFs in stomatology in four areas. It provides an overview of recent advances in the design and application of MOFs in stomatology from their intrinsic properties to different syntheses and their use as smart drug delivery systems or a combination of these.

Colloidal Chiral Carbon Dots: An Emerging System for Chiroptical Applications

Chiral CDots (c-CDots) not only inherit those merits from CDots but also exhibit chiral effects in optical, electric, and bio-properties. Therefore, c-CDots have received significant interest from a wide range of research communities including chemistry, physics, biology, and device engineers. They have already made decent progress in terms of synthesis, together with the exploration of their optical properties and applications. In this review, the chiroptical properties and chirality origin in extinction circular dichroism (ECD) and circularly polarized luminescence (CPL) of c-CDots is briefly discussed. Then, the synthetic strategies of c-CDots is summarized, including one-pot synthesis, post-functionalization of CDots with chiral ligands, and assembly of CDots into chiral architectures with soft chiral templates. Afterward, the chiral effects on the applications of c-CDots are elaborated. Research domains such as drug delivery, bio- or chemical sensing, regulation of enzyme-like catalysis, and others are covered. Finally, the perspective on the challenges associated with the synthetic strategies, understanding the origin of chirality, and potential applications is provided. This review not only discusses the latest developments of c-CDots but also helps toward a better understanding of the structure-property relationship along with their respective applications.

Chiral MoSe2 Nanoparticles for Ultrasensitive Monitoring of Reactive Oxygen Species In Vivo

Reactive oxygen species (ROS) are involved in neurodegenerative diseases, cancer, and acute hepatitis, and quantification of ROS is critical for the early diagnosis of these diseases. In this work, a novel probe is developed, based on chiral molybdenum diselenide (MoSe2 ) nanoparticles (NPs) modified by the fluorescent molecule, cyanine 3 (Cy3). Chiral MoSe2 NPs show intensive circular dichroism (CD) signals at 390 and 550 nm, whereas the fluorescence of Cy3 at 560 nm is quenched by MoSe2 NPs. In the presence of ROS, the probe reacts with the ROS and then oxidates rapidly, resulting in decreased CD signals and the recovery of the fluorescence. Using this strategy, the limit of detection values of CD and fluorescent signals in living cells are 0.0093 nmol/106 cells and 0.024 nmol/106 cells, respectively. The high selectivity and sensitivity to ROS in complex biological environments is attributed to the Mo4+ and Se2- oxidation reactions on the surface of the NPs. Furthermore, chiral MoSe2 NPs are able to monitor the levels of ROS in vivo by the fluorescence. Collectively, this strategy offers a new approach for ROS detection and has the potential to inspire others to explore chiral nanomaterials as biosensors to investigate biological events.

Rational designed Fe-ZIFs@CoP nanoplatforms for photothermal-enhanced ROS-mediated tumor therapy

Metal-organic frameworks (MOFs), with biocompatible and bio-friendly properties, exhibit intriguing potential for the drug delivery system and imaging-guided synergistic cancer theranostics. Even though tremendous attention has been attracted on MOFs-based therapeutics, which play a crucial role in therapeutic drugs, gene, and biomedical agents delivery of cancer therapy, they are often explored as simple nanocarriers without further "intelligent" functions. Herein, Fe-doped MOFs with CoP nanoparticles loading were rationally designed and synthesized for photothermal enhanced reactive oxygen species (ROS)-mediated treatment. Fe-ZIFs@CoP could generate efficient ROS through the Fenton reaction while depleting glutathione for amplifying oxidative stress. Particularly, due to the photothermal effect of Fe-ZIFs@CoP, the hyperthermia generated by as-synthesized Fe-ZIFs@CoP facilitated the advanced performance of the Fenton effect for a high amount of ROS generation. The promising "all-in-one" synergistic MOFs platform herein reported provides some prospects for future directions in this area.

Microfluidic chip and chiroptical gold nanoparticle-based colorimetric sensor for enantioselective detection of L-tryptophan

Herein, we introduce a novel integrated system that merges an enantio-discriminative bio-MOF-packed centrifugal microfluidic chip made from PDMS with a user-friendly on-site colorimetric sensor. This innovative approach enables the precise enantioselective recognition of L-tryptophane (L-Trp). This chiral recognition probe was successfully synthesized through meticulous control of nano-ovals-shaped gold nanoparticles morphology and surface passivation. The operational factor of this methodology was optimized to ensure simplicity, practicality, and efficiency. This optimization led to reduced reagent consumption and instantaneous analytical feedback. The integrated system was effectively applied for enantioselective separation and quantification of L-Trp across an extensive linear range of 50 μM-1.5 mM, impressive limit of detection as low as 15 μM. It is noteworthy that this integrated system demonstrated desirable selectivity even in the presence of similar biomolecules, showcasing its robust performance and rapid detection capability. Further extended the application of this strategy to exceptional performance across enantioselective sensing of L-Trp in various sample matrices, comprising bovine serum albumin, bovine milk, blood plasma and urine samples. This integrated microfluidic sample pretreatment, chiroptical sensing, and on-site signal recording with a smartphone hold tremendous potential for widespread implementation, practical applications engaging healthcare and environmental, food safety, and point-of-needs analysis, facilitating successive solution mixing and colorimetric detection.

Ligand induced chirality in In2S3 nanoparticles

Chiral inorganic nanostructures have attracted a lot of attention over the last few years. Here we report the first observation of chirality in indium sulfide nanoparticles, which have been produced by a co-precipitation reaction in the presence of cysteine as a chiral agent. The process resulted in the production of spherical nanoparticles with an average diameter of around 3.6 nm. Circular dichroism spectroscopy of the nanoparticles showed an intense chiroptical signal corresponding to the indium sulfide excitonic transition, confirming the successful transfer of chirality to the In2S3 inorganic matrix. Nuclear magnetic resonance analysis of a colloidal solution of the nanoparticles demonstrated critical evidence of chemisorption of the chiral ligand on the surface of the nanoparticles and revealed a characteristic fast chemical exchange between the ligand chemisorbed on the surface of the nanoparticles and the free ligand in solution. Finally, the effect of the chiral ligand's structure on the transfer of chirality was investigated, with consideration of other amino acid ligands, and the critical role of the thiolate group in the optimisation of the chiral transfer was observed. This research is expected to stimulate further development and applications of new chiral semiconductor nanomaterials.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

A STING pathway-activatable contrast agent for MRI-guided tumor immunoferroptosis synergistic therapy

The immunotherapy efficiency of stimulator of interferon genes (STING)-activatable drugs (e.g., 7-ethyl-10-hydroxycamptothecin, SN38) is limited by their non-specificity to tumor cells and the slow excretion of the DNA-containing exosomes from the treated cancer cells. The efficacy of tumor ferroptosis therapy is always limited by the elimination of lipid peroxides (LPO) by the pathways of glutathione peroxidase 4 (GPX4), dihydroorotate dehydrogenase (DHODH) and ferroptosis suppressor protein 1(FSP1). To solve these problems, in this study, we developed a STING pathway-activatable contrast agent (i.e., FeGd-HN@TA-Fe2+-SN38 nanoparticles) for magnetic resonance imaging (MRI)-guided tumor immunoferroptosis synergistic therapy. The remarkable in vivo MRI performance of FeGd-HN@TA-Fe2+-SN38 is attributed to its high accumulation at tumor location, the high relaxivities of FeGd-HN core, and the pH-sensitive TA-Fe2+-SN38 layer. The effectiveness and biosafety of the immunoferroptosis synergistic therapy induced by FeGd-HN@TA-Fe2+-SN38 are demonstrated by the in vivo investigations on the 4T1 tumor-bearing mice. The mechanisms of in vivo immunoferroptosis synergistic therapy by FeGd-HN@TA-Fe2+-SN38 are demonstrated by measurements of in vivo ROS, LPO, GPX4 and SLC7A11 levels, the intratumor matured DCs and CD8+ T cells, the protein expresion of STING and IRF-3, and the secretion of IFN-β and IFN-γ.

NIR-switchable local hydrogen generation by tandem bimetallic MOFs nanocomposites for enhanced chemodynamic therapy

The inadequate quantity of hydrogen peroxide (H2O2) in cancer cells promptly results in the constrained success of chemodynamic therapy (CDT). Significant efforts made throughout the years; nevertheless, researchers are still facing the great challenge of designing a CDT agent and securing H2O2 supply within the tumor cell. In this study, taking advantage of H2O2 level maintenance mechanism in cancer cells, a nanozyme-based bimetallic metal-organic frameworks (MOFs) tandem reactor is fabricated to elevate intracellular H2O2 levels, thereby enhancing CDT. In addition, under near-infrared excitation, the upconversion nanoparticles (UCNPs) loaded into the MOFs can perform photocatalysis and generate hydrogen, which increases cellular susceptibility to radicals induced from H2O2, inhibits cancer cell energy, causes DNA damages and induces tumor cell apoptosis, thus improving CDT therapeutic efficacy synergistically. The proposed nanozyme-based bimetallic MOFs-mediated CDT and UCNPs-mediated hydrogen therapy act as combined therapy with high efficacy and low toxicity.

Chiral probes for biosensing

Chiral inorganic nanomaterials have emerged as a highly promising area of research in nanoscience due to their exceptional light-matter interaction and vast potential applications in chiral sensing, asymmetric catalysis, enantiomer separation, and negative-index materials. We present an overview of the latest advances in chiral inorganic nanomaterials including chiral individual nanoparticles, chiral assemblies, and chiral film-based sensors over the past ten years. Additionally, we discuss the challenges and future perspectives for developing chiral nanomaterials in biosensing applications.

DNA Nanoribbon-Assisted Intracellular Biosynthesis of Fluorescent Gold Nanoclusters for Cancer Cell Imaging

Metal nanoclusters (NCs) have emerged as a promising class of fluorescent probes for cellular imaging due to their high resistance to photobleaching and low toxicity. Nevertheless, their widespread use in clinical diagnosis is limited by their unstable intracellular fluorescence. In this study, we develop an intracellularly biosynthesized fluorescent probe, DNA nanoribbon-gold NCs (DNR/AuNCs), for long-term cellular tracking. Our results show that DNR/AuNCs exhibit a 4-fold enhancement of intracellular fluorescence intensity compared to free AuNCs. We also investigated the mechanism underlying the fluorescence enhancement of AuNCs by DNRs. Our findings suggest that the higher synthesis efficiency and stability of AuNCs in the lysosome may contribute to their fluorescence enhancement, which enables long-term (up to 15 days) fluorescence imaging of cancer cells (enhancement of ∼60 times compared to free AuNCs). Furthermore, we observe similar results with other metal NCs, confirming the generality of the DNR-assisted biosynthesis approach for preparing highly bright and stable fluorescent metal NCs for cancer cell imaging.

Engineered rare-earth nanomaterials for fluorescence imaging and therapy

Early diagnosis and treatment are of great significance for hindering the progression of brain disease. The limited effects of available treatments and poor prognosis are currently the most pressing problems faced by clinicians and their patients. Therefore, developing new diagnosis and treatment programs for brain diseases is urgently needed. Near-infrared (NIR)-light-responsive, lanthanide-doped upconversion nanoparticles (UCNPs) provide great advantages both in diagnosis and therapy. Hence, we synthesised nanoparticles comprised of a UCNPs core with surface functionalization. UCNPs@Au was used for NIR fluorescence imaging in the brain and inhibiting the growth of mouse glioma 261 (GL261) cells depending on photothermal properties. In addition, a UCNPs core and a mesoporous silica layer as the outer shell with a tannic acid-Al3+ ions (TA-Al) complex as a "gatekeeper" were used for pH-triggered doxorubicin/small interfering ribonucleic acid delivery in vitro. Based on our preliminary results, we expect to develop more multifunctional nanoscale diagnostic and therapeutic agents based on UCNPs for the diagnosis and treatment of brain diseases, including Alzheimer's disease, Parkinson's disease, and brain tumours.

Chiral Materials: Progress, Applications, and Prospects

Chirality is a universal phenomenon in molecular and biological systems, denoting an asymmetric configurational property where an object cannot be superimposed onto its mirror image by any kind of translation or rotation, which is ubiquitous on the scale from neutrinos to spiral galaxies. Chirality plays a very important role in the life system. Many biological molecules in the life body show chirality, such as the "codebook" of the earth's biological diversity-DNA, nucleic acid, etc. Intriguingly, living organisms hierarchically consist of homochiral building blocks, for example, l-amino acids and d-sugars with unknown reason. When molecules with chirality interact with these chiral factors, only one conformation favors the positive development of life, that is, the chiral host environment can only selectively interact with chiral molecules of one of the conformations. The differences in chiral interactions are often manifested by chiral recognition, mutual matching, and interactions with chiral molecules, which means that the stereoselectivity of chiral molecules can produce changes in pharmacodynamics and pathology. Here, the latest investigations are summarized including the construction and applications of chiral materials based on natural small molecules as chiral source, natural biomacromolecules as chiral sources, and the material synthesized by design as a chiral source.

Why Ligand Doping Increases the Fluorescence of an Anthracene-Based Metal-Organic Framework

Metal-organic frameworks (MOFs) built from fluorescent ligands frequently exhibit enhanced fluorescence when doped with inert ligands. This study focuses on a MOF of the UiO-68 structure, which is built from a fluorescent dibenzoate-anthracene ligand doped with a dibenzoate-benzene ligand. Our investigation aims to understand the mechanism behind the doping-enhanced emission of this MOF. We rule out several possible mechanisms, including exciton coupling, electron transfer between ligand and metal center, and ligand intersystem crossing induced by the metal center. Inhibition of the interligand charge transfer is considered a possible way to enhance emission. Furthermore, we propose that the conformational change of the anthracene-based ligand in the MOF cavity is also a way for enhancement. Our molecular dynamics simulations of the MOF structure filled with solvents reveal that the steric crowding in the cavity induces a conformational change at different doping levels, affecting the rate of intersystem crossing of the ligand.

Surface ligand-assisted synthesis and biomedical applications of metal-organic framework nanocomposites

Metal-organic framework (MOF) nanocomposites have recently gained intensive attention for biosensing and disease therapy applications owing to their outstanding physiochemical properties. However, the direct growth of MOF nanocomposites is usually hindered by the mismatched lattice in the interface between the MOF and other nanocomponents. Surface ligands, molecules with surfactant-like properties, are demonstrated to exhibit the robust capability to modify the interfacial properties of nanomaterials and can be utilized as a powerful strategy for the synthesis of MOF nanocomposites. Besides this, surface ligands also exhibit significant functions in the morphological control and functionalization of MOF nanocomposites, thus greatly enhancing their performance in biomedical applications. In this review, the surface ligand-assisted synthesis and biomedical applications of MOF nanocomposites are comprehensively reviewed. Firstly, the synthesis of MOF nanocomposites is discussed according to the diverse roles of surface ligands. Then, MOF nanocomposites with different properties are listed with their applications in biosensing and disease therapy. Finally, current challenges and further directions of MOF nanocomposites are presented to motivate the development of MOF nanocomposites with elaborate structures, enriched functions, and excellent application prospects.

Upconversion nanoparticles anchored MnO2 nanosheets for luminescence "turn on" detecting hydrogen peroxide

The sensitively and reliably detecting hydrogen peroxide (H₂O₂) is of significant for biology and environment protection fields. Herein, we reported a high sensitive H₂O₂ nanoprobe based on upconversion nanoparticles (UCNPs) anchored MnO₂ nanosheets. In which, DNA modified NaYF₄@NaYF₄:Yb,Tm core-shell nanoparticles were anchored onto the MnO₂ nanosheets surface via π-π stacking. Owing to the luminescence resonance energy transfer, the blue luminescence of UCNPs was effectively quenched by MnO₂ nanosheets, then the luminescence could be restored by adding H₂O₂ for reducing MnO₂ to Mn²⁺, and achieving a H₂O₂ concentration-dependent luminescence change, the detection limit could reach to 0.23 nM (S/N = 3). The proposed method could detect H₂O₂ in serum, lake water and real samples. Thus, a desired upconversion luminescence sensing strategy for detection H₂O₂ in life and environmental analysis was successfully constructed. It may be provide a potential tool in disease diagnosis and environmental monitoring fields.

Strong fluorescence-detected two-photon circular dichroism of chiral gold nanoclusters

Progress in syntheses and understanding of the intriguing properties of chiral noble metal nanoclusters sparks interest to extend investigations of their chiroptical response to the nonlinear optics regime. We present a quantitative determination of two-photon circular dichroism of chiral gold nanoclusters with ATT and L- or D-Arg ligands (ATT = 6-aza-2-thiotymine and Arg = arginine). Introduction of arginine ligands enables the formation of two enantiomers of the nanoclusters, with strong chiroptical effects in both linear and nonlinear regime. We present two-photon absorption and luminescent properties measured in a wide range of wavelengths, with the two-photon absorption cross section reaching 1743 GM and two-photon brightness ∼1102 GM at 825 nm. We report strong, 245-fold enhancement of the two-photon circular dichroism of nanoclusters with respect to the one-photon absorption counterpart - the dissymmetry factor. The presence of multiple advantages of nanoclusters: high fluorescence quantum yield, strong nonlinear optical properties and well-controlled chirality is a powerful combination for applications of such clusters in multiphoton microscopy.

Understanding FRET in Upconversion Nanoparticle Nucleic Acid Biosensors

Upconversion nanoparticles (UCNPs) have been frequently applied in Förster resonance energy transfer (FRET) bioanalysis. However, the understanding of how surface coatings, bioconjugation, and dye-surface distance influence FRET biosensing performance has not significantly advanced. Here, we investigated UCNP-to-dye FRET DNA-hybridization assays in H₂O and D₂O using ∼24 nm large NaYF₄:Yb³⁺,Er³⁺ UCNPs coated with thin layers of silica (SiO₂) or poly(acrylic acid) (PAA). FRET resulted in strong distance-dependent PL intensity changes. However, the PL decay times were not significantly altered because of continuous Yb³⁺-to-Er³⁺ energy migration during Er³⁺-to-dye FRET. Direct bioconjugation of DNA to the thin PAA coating combined with the closest possible dye-surface distance resulted in optimal FRET performance with minor influence from competitive quenching by H₂O. The better comprehension of UCNP-to-dye FRET was successfully translated into a microRNA (miR-20a) FRET assay with a limit of detection of 100 fmol in a 80 μL sample volume.

DUCNP@Mn-MOF/FOE as a Highly Selective and Bioavailable Drug Delivery System for Synergistic Combination Cancer Therapy

Heterostructures comprising lanthanide-doped upconversion nanoparticles (DUCNPs) and metal-organic frameworks (MOFs) are emerging as promising nanosystems for integrating medical diagnosis and treatment. Here, the DUCNP@Mn-MOF nanocarrier was developed, which showed good efficiency for loading and delivering a cytotoxic antitumor agent (3-F-10-OH-evodiamine, FOE). The combined advantages of the pH-responsive and peroxidase-like properties of Mn-MOF and the unique optical features of DUCNPs granted the DUCNP@Mn-MOF/FOE system synergistic chemodynamic and chemotherapeutic effects. The DUCNP@Mn-MOF nanocarrier effectively overcame the intrinsic limitations of FOE, such as its unfavorable physicochemical properties and limited in vivo potency. This complexed nanosystem was responsive to the tumor microenvironment and showed excellent tumor targeting capability. Thus, DUCNP@Mn-MOF/FOE exhibited highly selective and bioavailable drug delivery properties and is promising for cancer therapy. In a mouse breast cancer model, DUCNP@Mn-MOF/FOE inhibited tumor growth without significant toxicity. Therefore, the proposed nanosystem represents a promising theragnostic platform for multimodal combination diagnosis and therapy of tumors.

Circularly Polarized Light-Enabled Chiral Nanomaterials: From Fabrication to Application

For decades, chiral nanomaterials have been extensively studied because of their extraordinary properties. Chiral nanostructures have attracted a lot of interest because of their potential applications including biosensing, asymmetric catalysis, optical devices, and negative index materials. Circularly polarized light (CPL) is the most attractive source for chirality owing to its high availability, and now it has been used as a chiral source for the preparation of chiral matter. In this review, the recent progress in the field of CPL-enabled chiral nanomaterials is summarized. Firstly, the recent advancements in the fabrication of chiral materials using circularly polarized light are described, focusing on the unique strategies. Secondly, an overview of the potential applications of chiral nanomaterials driven by CPL is provided, with a particular emphasis on biosensing, catalysis, and phototherapy. Finally, a perspective on the challenges in the field of CPL-enabled chiral nanomaterials is given.

Metal-Organic Frameworks-Based Optical Nanosensors for Analytical and Bioanalytical Applications

Metal-organic frameworks (MOFs)-based optical nanoprobes for luminescence and surface-enhanced Raman spectroscopy (SERS) applications have been receiving tremendous attention. Every element in the MOF structure, including the metal nodes, the organic linkers, and the guest molecules, can be used as a source to build single/multi-emission signals for the intended analytical purposes. For SERS applications, the MOF can not only be used directly as a SERS substrate, but can also improve the stability and reproducibility of the metal-based substrates. Additionally, the porosity and large specific surface area give MOF a sieving effect and target molecule enrichment ability, both of which are helpful for improving detection selectivity and sensitivity. This mini-review summarizes the advances of MOF-based optical detection methods, including luminescence and SERS, and also provides perspectives on future efforts.

LnNP@ZIF8 Smart System for In Situ NIR-II Ratiometric Imaging-Based Tumor Drug Resistance Evaluation

Just-in-time evaluation of drug resistance in situ will greatly facilitate the achievement of precision cancer therapy. The rapid elevation of reactive oxygen species (ROS) is the key to chemotherapy. Hence, suppressed ROS production is an important marker for chemotherapy drug resistance. Herein, a NIR-II emission smart nanoprobe (LnNP@ZIF8, consisting of a lanthanide-doped nanoparticle (LnNP) core and metal-organic framework shell (ZIF8)) is constructed for drug delivery and in vivo NIR-II ratiometric imaging of ROS for tumor drug resistance evaluation. The drug-loaded nanoprobes release therapeutic substances for chemotherapy in the acidic tumor tissue. As the level of ROS increases, the LnNPs shows responsively descending fluorescence intensity at 1550 nm excited by 980 nm (F1550, 980Ex), while the fluorescence of the LnNPs at 1060 nm excited by 808 nm (F1060, 808Ex) is stable. Due to the ratiometric F1550, 980Ex/F1060, 808Ex value exhibiting a linear relationship with ROS concentration, NIR-II imaging results of ROS change based on this ratio can be an important basis for determining tumor drug resistance. As the chemotherapy and resistance evaluation are explored continuously in situ, the ratiometric imaging identifies drug resistance successfully within 24 h, which can greatly improve the timeliness of accurate treatment.

Recent Advances of Anticancer Studies Based on Nano-Fluorescent Metal-Organic Frameworks

Nano-fluorescent metal-organic frameworks (NF-MOFs), a kind of newly emerged nano-scaled platform, can provide visual, rapid, and highly sensitive optical imaging of cancer lesions both in vitro and in vivo. Meanwhile, the excellent porosity, structural tunability, and chemical modifiability also enable NF-MOFs to achieve simultaneous loading of targeted molecules and therapeutic agents. These NF-MOFs not only possess excellent targeted imaging ability, but also can guide the carried cargos to perform precise therapy, drawing considerable attention in current framework of anticancer drug design. In this review, we outline the fluorescence types and response mechanisms of NF-MOFs, and highlight their applications in cancer diagnosis and therapy in recent years. Based on this panorama, we also discuss current issues and future trends of NF-MOFs in biomedical fields, attempting to clarify the potential value of fluorescence imaging guided anticancer investigations.

The Challenges of O2 Detection in Biological Fluids: Classical Methods and Translation to Clinical Applications

Dissolved oxygen (DO) is deeply involved in preserving the life of cellular tissues and human beings due to its key role in cellular metabolism: its alterations may reflect important pathophysiological conditions. DO levels are measured to identify pathological conditions, explain pathophysiological mechanisms, and monitor the efficacy of therapeutic approaches. This is particularly relevant when the measurements are performed in vivo but also in contexts where a variety of biological and synthetic media are used, such as ex vivo organ perfusion. A reliable measurement of medium oxygenation ensures a high-quality process. It is crucial to provide a high-accuracy, real-time method for DO quantification, which could be robust towards different medium compositions and temperatures. In fact, biological fluids and synthetic clinical fluids represent a challenging environment where DO interacts with various compounds and can change continuously and dynamically, and further precaution is needed to obtain reliable results. This study aims to present and discuss the main oxygen detection and quantification methods, focusing on the technical needs for their translation to clinical practice. Firstly, we resumed all the main methodologies and advancements concerning dissolved oxygen determination. After identifying the main groups of all the available techniques for DO sensing based on their mechanisms and applicability, we focused on transferring the most promising approaches to a clinical in vivo/ex vivo setting.

ROS generation strategy based on biomimetic nanosheets by self-assembly of nanozymes

Reactive oxygen species (ROS) play an important role in physiology and have been applied in tumor therapy. However, insufficient endogenous H₂O₂ and hypoxia in cancer cells can lead to limited ROS production and poor therapeutic efficacy. Herein, we develop a biomimetic nanosheet material based on the self-assembly of nanozymes that could supply H₂O₂ under acidic conditions and catalyze a cascade of intracellular biochemical reactions to produce ROS under both normoxic and hypoxic conditions without any external stimuli. In this system, the copper peroxide nanosheets (CPNS), which are pH-responsive, were prepared through coordination of H₂O₂ to Cu²⁺ and then modified using ultrafine Pt NPs to form CPNS@Pt. The CPNS could decompose under acidic conditions, allowing the simultaneous release of Fenton catalytic Cu²⁺ and H₂O₂ accompanied by a Fenton-type reaction between them. On the other hand, Pt NPs were also released. The released Pt NPs behave as an oxidase mimic and catalase mimic. In this way, the well-defined CPNS@Pt can not only relieve hypoxic conditions but also generate ROS to induce cell apoptosis, thereby paving the way for the development of a nanozyme with multienzyme activity as a therapeutic strategy.