Engineered Microrobots for Targeted Delivery of Bacterial Outer Membrane Vesicles (OMV) in Thrombus Therapy.

In the realm of thrombosis treatment, bioengineered outer membrane vesicles (OMVs) offer a novel and promising approach, as they have rich content of bacterial-derived components. This study centers on OMVs derived from Escherichia coli BL21 cells, innovatively engineered to encapsulate the staphylokinase-hirudin fusion protein (SFH). SFH synergizes the properties of staphylokinase (SAK) and hirudin (HV) to enhance thrombolytic efficiency while reducing the risks associated with re-embolization and bleeding. Building on this foundation, this study introduces two cutting-edge microrobotic platforms: SFH-OMV@H for venous thromboembolism (VTE) treatment, and SFH-OMV@MΦ, designed specifically for cerebral venous sinus thrombosis (CVST) therapy. These platforms have demonstrated significant efficacy in dissolving thrombi, with SFH-OMV@H showcasing precise vascular navigation and SFH-OMV@MΦ effectively targeting cerebral thrombi. The study shows that the integration of these bioengineered OMVs and microrobotic systems marks a significant advancement in thrombosis treatment, underlining their potential to revolutionize personalized medical approaches to complex health conditions.

Drug-drug conjugates self-assembled nanomedicines triggered photo-/immuno- therapy for synergistic cancer treatments.

Although immunotherapies have made progress in cancer treatment, their clinical response rates vary widely and are typically low due to sparse immune cell infiltration (immune "cold") and suppressive tumor immune microenvironment (TIME). A simple yet effective approach that integrates a variety of immune-stimulating and TIME-modulating functions could potentially address this clinical challenge. Herein, we conjugate two small molecules, including a photosensitizer (pyropheophorbide-a, PA) and a Toll-like receptor 7/8 agonist (resiquimod, R848), into prodrug (PA-R848) that self-assembles into PA-R848 esterase responsive nanoparticles (PARE NPs) with 100% drug composition and synergistic photo-/immune- therapeutic effects. In PARE NPs, PA exhibits strong phototherapeutic effects which ablate the primary tumor directly and elicits immunogenic cell death (ICD) to promote the immune response. R848 effectively polarizes the M2-type tumor-associated macrophage (TAM) to M1-type TAM, consequently reversing the "cold" and suppressive TIME when working together with phototherapy. The PARE NPs can efficiently pare down the tumor development by two synergisms, including i) synergistic immunotherapy between ICD and TAM polarization; ii) and the antitumor effects between phototherapy and immunotherapy. On a head-neck squamous cell carcinoma mouse model, PARE NPs combined with PD-1 antibody eliminate primary tumors, and significantly inhibit the progress of distant tumors thanks to the robust antitumor immunity enhanced by the PARE NPs.

A pH-Driven Small-Molecule Nanotransformer Hijacks Lysosomes and Overcomes Autophagy-Induced Resistance in Cancer.

Smart conversion of supramolecular structures in vivo is an attractive strategy in cancer nanomedicine, which is usually achieved via specific peptide sequences. Here we developed a lysosomal targeting small-molecule conjugate, PBC, which self-assembles into nanoparticles at physiological pH and smartly converts to nanofibrils in lysosomes of tumor cells. Such a transformation mechanically leads to lysosomal dysfunction, autophagy inhibition, and unusual cytoplasmic vacuolation, thus granting PBC a unique anticancer activity as a monotherapy. Importantly, the photo-activated PBC elicits significant phototoxicity to lysosomes and shows enormous advantages in overcoming autophagy-caused treatment resistance frequently occurring in conventional phototherapy. This improved phototherapy achieves a complete cure of oral cancer xenografts upon limited administration. Our work provides a new paradigm for the construction of nonpeptide nanotransformers with biomedical activities.

A mitochondria-targeting lipid-small molecule hybrid nanoparticle for imaging and therapy in an orthotopic glioma model.

Hybrid lipid‒nanoparticle complexes have shown attractive characteristics as drug carriers due to their integrated advantages from liposomes and nanoparticles. Here we developed a kind of lipid-small molecule hybrid nanoparticles (LPHNPs) for imaging and treatment in an orthotopic glioma model. LPHNPs were prepared by engineering the co-assembly of lipids and an amphiphilic pheophorbide a‒quinolinium conjugate (PQC), a mitochondria-targeting small molecule. Compared with the pure nanofiber self-assembled by PQC, LPHNPs not only preserve the comparable antiproliferative potency, but also possess a spherical nanostructure that allows the PQC molecules to be administrated through intravenous injection. Also, this co-assembly remarkably improved the drug-loading capacity and formulation stability against the physical encapsulation using conventional liposomes. By integrating the advantages from liposome and PQC molecule, LPHNPs have minimal system toxicity, enhanced potency of photodynamic therapy (PDT) and visualization capacities of drug biodistribution and tumor imaging. The hybrid nanoparticle demonstrates excellent curative effects to significantly prolong the survival of mice with the orthotopic glioma. The unique co-assembly of lipid and small molecule provides new potential for constructing new liposome-derived nanoformulations and improving cancer treatment.

Single Small Molecule-Assembled Mitochondria Targeting Nanofibers for Enhanced Photodynamic Cancer Therapy in Vivo.

Photodynamic therapy (PDT) has emerged as an attractive alternative in cancer therapy, but its therapeutic effects are limited by the nonselective subcellular localization and poor intratumoral retention of small-molecule photosensitizes. Here a fiber-forming nanophotosensitizer (PQC NF) that is composed of mitochondria targeting small molecules of amphiphilicity is reported. Harnessing the specific mitochondria targeting, the light-activated PQC NFs produce approximately 110-fold higher amount of reactive oxygen species (ROS) in cells than free photosensitizers and can dramatically induce mitochondrial disruption to trigger intense apoptosis, showing 20-50 times better in vitro anticancer potency than traditional photosensitizers. As fiber-shaped nanomaterials, PQC NFs also demonstrated a long-term retention in tumor sites, solving the challenge of rapid clearance of small-molecule photosensitizers from tumors. With these advantages, PQC NFs achieve a 100% complete cure rate in both subcutaneous and orthotopic oral cancer models with the administration of only a single dose. This type of single small molecule-assembled mitochondria targeting nanofibers offer an advantageous strategy to improve the in vivo therapeutic effects of conventional PDT.

Reducing background absorbance via a double-lock strategy for detection of alkaline phosphatase and α-fetoprotein.

Lowering the background signal for more sensitive analysis of determinands is as important as amplifying the target signal. The photoinduced oxidase of fluorescein has been reported, which can catalyze the oxidization of common substrates in a few minutes. As a metaphor for locks and keys, we designed double locks confining the activity of fluorescein to reduce the background absorbance during colorimetric detection. The first lock inhibits the main activity of fluorescein by phosphating. The second lock almost completely deactivates fluorescein by forming coordination nanoparticles (CNPs) via the self-assembly of cerium chloride and fluorescein diphosphate (FDP). The Ce-FDP CNPs are characterized by scanning electron microscope (SEM), dynamic light scattering (DLS), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectrum (EDS), which show electrostatic formation and amorphous character in the morphology. Alkaline phosphatase (ALP), the key to release fluorescein, can destroy Ce-FDP CNPs along with decomposing FDP by degrading phosphate groups. Therefore, a novel colorimetric strategy for sensitive detection of ALP is established. The detection of α-fetoprotein (AFP) is further succeeded by labeling AFP antibody with ALP. By dramatically reducing the background absorbance, the detection limits of ALP and AFP are as low as 0.014 mU/mL and 0.023 ng/mL, respectively. This convenient, brief, sensitive assay provides a promising prospect for clinical diagnosis. Graphical abstract.

A signal amplification strategy for prostate specific antigen detection via releasing oxidase-mimics from coordination nanoparticles by alkaline phosphatase.

A novel signal amplification method for prostate specific antigen (PSA) is developed by freeing fluorescein with photoinduced oxidase-like activity from coordination nanoparticles (CNPs) in the presence of alkaline phosphatase (ALP). CNPs loaded with fluorescein (F@CNPs) are obtained in aqueous solution by self-assembly using Tb3+ as metal ion, guanosine monophosphate (5'-GMP) as ligand, and fluorescein as signal molecule. The F@CNPs display outstanding properties of simple synthesis, low cost, good water solubility, negligible leakage and satisfactory load capacity. Fluorescein is quantitatively encapsulated in CNPs with a binding ratio of 92.72%. Meanwhile, ALP can specifically hydrolyze the phosphate group of 5'-GMP ligand, triggering the destruction of F@CNPs and leakage of fluorescein. Fluorescein, a photoinduced oxidase mimic, can catalyze the oxidation of non-fluorescent Amplex UltraRed (AUR) into fluorescent resorufin under LED lamp. This strategy exhibits good sensitivity for ALP detection. In addition, a new immunoassay for PSA is validated by labelling ALP on PSA antibody. The low detection limit of 0.04 ng mL-1 in detecting PSA is appropriate for PSA detection in real samples. Therefore, the work not only establishes a new strategy for ALP and PSA determination, but also provides a new conception for putting photoinduced oxidase-like fluorescein in practical application.

A siramesine-loaded metal organic framework nanoplatform for overcoming multidrug resistance with efficient cancer cell targeting.

Cancer is the leading cause of death and the most important obstacle to increasing life expectancy. With the sophisticated design and research of anticancer drugs, multidrug resistance to chemotherapy has become more and more common. After the emergence of multidrug resistance, the development of a new drug is beset with difficulties. The repurposing of non-anticancer drugs is thus a timely strategy for cancer therapy. Here, we highlight the potential of repurposing siramesine, a central nervous system drug for antitumor research and we construct a metal organic framework-based nanoplatform for effective intracellular accumulation and pH-response siramesine release. The released drug induces lysosome membrane permeabilization, leading to lysosomal cathepsins leakage and then results in cell apoptosis. Due to the modification of folic acids, the constructed drug delivery nanosystem shows good biocompatibility and efficient cancer cell targeting. Importantly, the drug delivery system shows enhanced anticancer efficacy in vitro, which not only effectively kills cancer cells but also kills multidrug resistant cells. Thus, the drug delivery nanosystem constructed in this study is thought to become a promising anticancer agent for cancer therapy and even overcoming multidrug resistance, which provides good prospects for biomedical applications.

Cetyltrimethylammonium chloride-loaded mesoporous silica nanoparticles as a mitochondrion-targeting agent for tumor therapy.

Mitochondria play an important role in supplying cellular energy, cell signaling and governing cell death. In addition, mitochondria have also been proved to be essential for tumor generation and development. Thus, mitochondrion-targeting therapeutics and treatments have emerged as promising strategies against cancer. However, the lack of mitochondrion-targeting agents has limited their application. To this end, we report cetyltrimethylammonium chloride-loaded mesoporous silica nanoparticles conjugated with human serum albumin (CTAC@MSNs-HSA) as a mitochondrion-targeting agent for anticancer treatment. As the structure-directing agent in the synthesis of MSNs, CTAC is stored within MSNs. Due to their desirable size and HSA receptor-mediated transcytosis, CTAC@MSNs-HSA show great cellular uptake and enhanced accumulation in the cytoplasm. Positively charged CTAC could actively target mitochondria by interacting with the negatively charged mitochondria membrane, and then lead to the dysfunction of mitochondria by decreasing mitochondrial potential and intracellular ATP levels, resulting in the necrosis and apoptosis of MCF-7 cells. Therefore, significant antitumor activity is observed by in vitro studies. Moreover, in vivo studies confirm that the CTAC@MSNs-HSA are able to induce cancer cell death and efficiently inhibit tumor growth. These results demonstrate the potential of CTAC@MSNs-HSA in cancer therapeutics as well as providing insights into mitochondrion-targeting treatment.

New optical method for the determination of ß-galactosidase and α-fetoprotein based on oxidase-like activity of fluorescein.

Fluorescein has been found as an efficient visible-light-induced oxidase mimic and its catalytic performance is group-dependent. Herein, a facile colorimetric strategy for ß-galactosidase (ß-gal) was developed using fluorescein di ß-D-galactopyranoside (FDG) as a probe based on the analyte induced change in oxidase mimicking activity of fluorescein derivatives. FDG doesn't possess any visible-light-induced oxidase activity and can generate fluorescein and fluorescein mono ß-D-galactopyranoside (FMG) in the presence of ß-gal. The in situ generated fluorescein and FMG possess high oxidase-like activities under visible-light illumination and could catalyze the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB) upon short irradiation by light-emitting diode (LED) lamp. Thus, the ß-gal activity can be selectively detected in linear range from 0.10 to 12.9 µg mL-1 with a limit of detection (LOD) of 0.04 µg mL-1. We further integrated with the visual detection of α-fetoprotein antigen (AFP) based on the corresponding colorimetric signal induced by ß-gal-linked colorimetric immunoassay, a LOD of 0.08 ng mL-1 could be achieved. Significantly, our proposed assay provides a facile sensing platform based on the change in enzyme mimicking activity induced by analytes. In addition, this optical method works without complex synthesis procedure and efficiently avoids participation of unstable H2O2 as an oxidant. Therefore, the present work not only shows the excellent assay performance in ß-gal and tumor biomarker detection, but also opens up a new avenue for its application in practical optical sensing.

Combination of 3-methyladenine therapy and Asn-Gly-Arg (NGR)-modified mesoporous silica nanoparticles loaded with temozolomide for glioma therapy in vitro.

Mesoporous silica nanoparticles (MSNPs) of a small diameter were loaded with the anticancer drug temozolomide (TMZ), coated with polydopamine (PDA), and conjugated with Asn-Gly-Arg (NGR) for use in the treatment of glioma. The accumulation of NGR-MSNPs in C6 cells was shown to be higher than that of unmodified MSNPs. Anticancer drugs can cause autophagy in tumor cells, whereas autophagy inhibitors can block this reaction and enhance the therapeutic effect of the drugs. In this study, we demonstrated that MSNP-TMZ-PDA-NGR had stronger autophagy- and apoptosis-inducing effects in C6 cells than TMZ alone, and its anticancer effect was further enhanced when combined with autophagy inhibition. These results demonstrate that the combination of targeting vehicles and autophagy inhibitors may have research value in the treatment of gliomas.

Quantum dots-based sandwich immunoassay for sensitive detection of Alzheimer's disease-related Aß1-42.

Amyloid-beta peptide 1-42 (Aß1-42) is known as a component of amyloid plaques in association with Alzheimer's disease. Herein, we developed a reliable and remarkably sensitive sandwich immunoassay to detect the Aß1-42 using quantum dots (QDs) as fluorescent label. In the presence of Aß1-42, the biotinylated Anti-beta Amyloid 1-16 (N-Ab) recognized the target and formed C-Ab-Aß1-42-N-Ab sandwich immunocomplexes. Then Streptavidin-QDs conjugated to biotinylated N-Ab and the concentration of Aß1-42 was determined by detecting the fluorescence intensity in the supernatant. This method is faster and more efficient than the previous approach we reported. It also has reasonable sensitivity and selectivity. Under the optimized conditions, the linear range is 5.0 to 100 pM (0.023-0.45 ng/mL) and the detection limit is 1.7 pM (7.6 pg/ mL). In addition, this method has been successfully applied to detect the Aß1-42 in human cerebrospinal fluid sample.

Hollow carbon dots labeled with FITC or TRITC for use in fluorescent cellular imaging.

Hollow carbon dots (HCDs) were prepared by a solvothermal method and conjugated to either tetramethyl rhodamine isothiocyanate (TRITC) or fluorescein-5-isothiocyanate (FITC). This resulted in HCDs with bright red or green fluorescence, with excitation/emission peaks at 550/580 and 491/520 nm, respectively. The nanocomposites are well water-soluble, remarkably photostable and biocompatible. In addition, the fluorescence of the composites is more stable in a reactive oxygen environment than the free dyes. Confocal images indicate that the nanoparticles quickly enter A549 cells and mainly accumulate in the cytoplasm. The wavelength of functionalized HCDs can be regulating via coupling the HCDs to different dyes. These results demonstrate that these composite materials can be very promising reagents for biological labeling and imaging. Graphical abstract Schematic of the preparation of hollow carbon dots conjugated to tetramethyl rhodamine isothiocyanate (RHCDs) by solvothermal method. The material is water-soluble, remarkably photostable and biocompatible. It was applied to cellular labeling and imaging.

Targeted H+-Triggered Bubble-Generating Nanosystems for Effective Therapy in Cancer Cells.

A novel targeting drug delivery system for cancer therapy based on H+-triggered bubble-generating nanosystems (BGNSs) was engineered. First, hollow mesoporous silica nanoparticles (HMSNs) were used to load doxorubicin (DOX). Then, the obtained drug-loaded HMSNs were treated with NaHCO3 to prepare the BGNSs. The BGNSs were coated with polydopamine (pDA), and finally, folic acids (FA) were anchored on the nanosystems to obtain the desired nanoscale drug delivery system (BGNSs@pDA-FA). BGNSs@pDA-FA was effectively internalized by cancer cells through folate receptor-mediated endocytosis and generated CO2 bubbles under the acidic environment of the lysosomes, thus enhancing lysosomal membrane permeability (LMP) to release caspase-3 into the cytoplasm, resulting in cancer cell death via an apoptosis-like pathway. Notably, we demonstrated that the BGNSs@pDA-FA exhibited a significant simultaneous synergetic cytotoxicity against MCF-7 cells and remarkably overcame the multidrug resistance (MDR) of MCF-7/ADR cells. Moreover, compared to free DOX and a nanosystem without FA modification (BGNSs), the BGNSs@pDA-FA induced relatively minor side effects in the MCF-10A cells. Therefore, the results showed that BGNSs@pDA-FA, as a targeted drug delivery system, have a good probability of overcoming the MDR of tumor cells with minor side effects on normal cells.