A mitochondria-targeting heptamethine cyanine-chlorambucil formulated polymeric nanoparticle to potentiate native tumor chemotherapeutic efficacy.

Chlorambucil (Cbl) is a DNA alkylating drug in the nitrogen mustard family, but the clinical applications of nitrogen mustard antitumor drugs are frequently limited by their poor aqueous solubility, poor cellular uptake, lack of targeting, and severe side effects. Additionally, mitochondria are the energy factories for cells, and tumor cells are more susceptible to mitochondrial dysfunction than some healthy cells, thus making mitochondria an important target for tumor therapy. As a proof-of-concept, direct delivery of Cbl to tumor cells' mitochondria will probably bring about new opportunities for the nitrogen mustard family. Furthermore, IR775 chloride is a small-molecule lipophilic cationic heptamethine cyanine dye with potential advantages of mitochondria targeting, near-infrared (NIR) fluorescence imaging, and preferential internalization towards tumor cells. Here, an amphiphilic drug conjugate was facilely prepared by covalently coupling chlorambucil with IR775 chloride and further self-assembly to form a carrier-free self-delivery theranostic system, in which the two components are both functional units aimed at theranostic improvement. The theranostic IR775-Cbl potentiated typical "1 + 1 > 2" tumor inhibition through specific accumulation in mitochondria, which triggered a remarkable decrease in mitochondrial membrane potential and ATP generation. In vivo biodistribution and kinetic monitoring were achieved by real-time NIR fluorescence imaging to observe its transport inside a living body. Current facile mitochondria-targeting modification with clinically applied drugs was promising for endowing traditional drugs with targeting, imaging, and improved potency in disease theranostics.

Programmable Photoswitchable Microcapsules Enable Precise and Tailored Drug Delivery from Microfluidics.

The development of precision personalized medicine poses a significant need for the next generation of advanced diagnostic and therapeutic technologies, and one of the key challenges is the development of highly time-, space-, and dose-controllable drug delivery systems that respond to the complex physiopathology of patient populations. In response to this challenge, an increasing number of stimuli-responsive smart materials are integrated into biomaterial systems for precise targeted drug delivery. Among them, responsive microcapsules prepared by droplet microfluidics have received much attention. In this study, we present a UV-visible light cycling mediated photoswitchable microcapsule (PMC) with dynamic permeability-switching capability for precise and tailored drug release. The PMCs were fabricated using a programmable pulsed aerodynamic printing (PPAP) technique, encapsulating an aqueous core containing magnetic nanoparticles and the drug doxorubicin (DOX) within a poly(lactic-co-glycolic acid) (PLGA) composite shell modified by PEG-b-PSPA. Selective irradiation of PMCs with ultraviolet (UV) or visible light (Vis) allows for high-precision time-, space-, and dose-controlled release of the therapeutic agent. An experimentally validated theoretical model was developed to describe the drug release pattern, holding promise for future customized programmable drug release applications. The therapeutic efficacy and value of patternable cancer cell treatment activated by UV radiation is demonstrated by our experimental results. After in vitro transcatheter arterial chemoembolization (TACE), PMCs can be removed by external magnetic fields to mitigate potential side effects. Our findings demonstrate that PMCs have the potential to integrate embolization, on-demand drug delivery, magnetic actuation, and imaging properties, highlighting their immense potential for tailored drug delivery and embolic therapy.

Self-Amplified Cascade Degradation and Oxidative Stress Via Rational pH Regulation of Oxidation-Responsive Poly(ferrocene) Aggregates.

Precise activation of polymer nanoparticles at lesion sites is crucial to achieve favorable therapeutic efficacy. However, conventional endogenous stimuli-responsive polymer nanoparticles probably suffer from few triggers to stimulate the polymer degradation and subsequent functions. Here, we describe oxidation-responsive poly(ferrocene) amphiphiles containing phenylboronic acid ester and ferrocene as the repeating backbone units. Upon triggering by hydrogen peroxide inside the tumor cells, the phenylboronic acid ester bonds are broken and poly(ferrocene) units are degraded to afford free ferrocene and noticeable hydroxide ions. The released hydroxide ions can immediately improve the pH value within the poly(ferrocene) aggregates, and the degradation rate of the phenylboronic acid ester backbone is further promoted by the upregulated pH; thereupon, the accelerated degradation can release much more additional hydroxide ions to improve the pH, thus achieving a positive self-amplified cascade degradation of poly(ferrocene) aggregates accompanied by oxidative stress boosting and efficient cargo release. Specifically, the poly(ferrocene) aggregates can be degraded up to ∼90% within 12 h when triggered by H2O2, while ferrocene-free control nanoparticles are degraded by only 30% within 12 days. In addition, the maleimide moieties tethered in the hydrophilic corona can capture blood albumin to form an albumin-rich protein corona and significantly improve favorable tumor accumulation. The current oxidation-responsive poly(ferrocene) amphiphiles can efficiently inhibit tumors in vitro and in vivo. This work provides a proof-of-concept paradigm for self-amplified polymer degradation and concurrent oxidative stress, which is promising in actively regulated precision medicine.

Self-Immolative Amphiphilic Poly(ferrocenes) for Synergistic Amplification of Oxidative Stress in Tumor Therapy.

Amphiphilic self-immolative polymers (SIPs) can achieve complete degradation solely through one triggerable event, which potentially optimize the blood clearance and uncontrollable/inert degradability for therapeutic nanoparticles. Herein, we report self-immolative amphiphilic poly(ferrocenes), BPnbs -Fc, composed by self-immolative backbone and aminoferrocene (AFc) side chains as well as end-capping poly(ethylene glycol) monomethyl ether. Upon triggering by tumor acidic milieu, the BPnbs -Fc nanoparticles readily degrade to release azaquinone methide (AQM) moieties, which can rapidly deplete intracellular glutathione (GSH) to cascade release AFc. Furthermore, both AFc and its product Fe2+ can catalyze intracellular hydrogen peroxide (H2 O2 ) into highly reactive hydroxyl radicals (⋅OH), thus amplifying the oxidative stress of tumor cells. Rational synergy of GSH depletion and ⋅OH burst can efficiently inhibit tumor growth by the SIPs in vitro and in vivo. This work provides an elegant design to adopt innate tumor milieu-triggerable SIPs degradation to boost cellular oxidative stress, which is a promising candidate for precision medicine.

A Native Drug-Free Macromolecular Therapeutic to Trigger Mutual Reinforcing of Endoplasmic Reticulum Stress and Mitochondrial Dysfunction for Cancer Treatment.

Drug-free macromolecular therapeutics are promising alternatives to traditional drugs. Nanomedicines with multiple organelles targeting can potentially increase the efficacy. Herein, a drug-free macromolecular therapeutic was designed to formulate endoplasmic reticulum (ER) and mitochondria dual-targeting nanoparticles (EMT-NPs), which can synergistically elicit ER stress and mitochondrial dysfunction. In vitro experiments indicated that EMT-NPs could effectively enter ER and mitochondria at an approximate ratio of 2 to 3. Subsequently, EMT-NPs could upregulate ER stress-related protein expression (IRE1α, CHOP), boosting calcium ion (Ca2+) efflux and activating the caspase-12 signaling cascade in cancer cells. In addition, EMT-NPs induced direct oxidative stress in mitochondria; some mitochondrial-related apoptotic events such as decreased mitochondrial membrane potential (MMP), upregulation of Bax, cytochrome c release, and caspase-3 activation were also observed for tumor cells upon incubation with EMT-NPs. Furthermore, the leaked Ca2+ from ER could induce mitochondrial Ca2+ overloading to further augment cancer cell apoptosis. In brief, mitochondrial and ER signaling networks collaborated well to promote cancer cell death. Extended photoacoustic and fluorescence imaging served well for the treatment of in vivo patient-derived xenografts cancer model. This drug-free macromolecular strategy with multiple subcellular targeting provides a potential paradigm for cancer theranostics in precision nanomedicine.

Discovery of 1-hydroxy-2-methylquinolin-4(1H)-one derivatives as new cytochrome bd oxidase inhibitors for tuberculosis therapy.

The cytochrome bcc-aa3 oxidase (Cyt-bcc) of Mycobacterium tuberculosis (Mtb) is a promising anti-tuberculosis target. However, when Cyt-bcc is inhibited, cytochrome bd terminal oxidase (Cyt-bd) can still maintain the activity of the respiratory chain and drive ATP synthesis. Through virtual screening and biological validation, we discovered two FDA-approved drugs, ivacaftor and roquinimex, exhibited moderate binding affinity to Cyt-bd. Structural modifications of them led to 1-hydroxy-2-methylquinolin-4(1H)-one derivatives as potent new Cyt-bd inhibitors. Compound 8d binds to Cyt-bd with a Kd value of 4.17 µM and inhibits the growth of the Cyt-bcc knock-out strain (ΔqcrCAB, Cyt-bd+) with a MIC value of 6.25 µM. The combination of 8d with the Cyt-bcc inhibitor Q203 completely inhibited oxygen consumption of the wild-type strain and the inverted-membrane vesicles expressing M. tuberculosis Cyt-bd (ΔcydAB::MtbCydAB+). Our study provides a promising starting point for the development of novel dual chemotherapies for tuberculosis.

Pulsed Laser Excited Photoacoustic Effect for Disease Diagnosis and Therapy.

Pulsed laser can excite light absorber to generate photoacoustic (PA) effect, that is, when the absorber is irradiated with pulsed laser, the absorbed light energy is converted into local heat to cause rapid thermoelastic expansion and generate acoustic wave. The generated PA signal has been widely employed for the diagnosis of many diseases with superb contrast, high penetrability and sensitivity. In addition, with the increase of pulsed laser energy, the resulting PA shockwave and cavitation can promote efficient drug release at lesion sites to potentiate the resulting therapeutic efficacy. Furthermore, the PA shockwave/cavitation can mechanically inhibit disease and produce reactive species. In this Concept article, the principle and research status of pulsed laser excited disease theranostics are briefly summarized, extra suggestions are proposed to inspire extensive PA probes and photodynamic materials as well as novel methodologies.

Efficient Transient Expression of Plasmid DNA Using Poly (2-(N,N-Dimethylamino) Ethyl Methacrylate) in Plant Cells.

Nanomaterials have been widely studied for their potential to become the new generation of nanocarriers in gene transfection, yet it remains still difficult to apply them efficiently and succinctly to plant cells. Poly (2-(N,N-dimethylamino) ethyl methacrylate) (PDMAEMA), which possesses temperature and pH dual-sensitivity, has largely been applied in animal cells, but it is rarely involved in plant cells. As a proof of concept, PDMAEMA as a gene carrier is incubated with plasmid GFP (pGFP) to explore its transfection ability in plants, and cationic polymer polyethylenimine (PEI) is used as a control. pGFP was efficiently condensed into the nanostructure by electrostatic interactions at an N/P (amino group from cationic polymers/phosphate group from plasmid DNA (pDNA)) ratio of 15; after complexation into nanocarriers, pGFP was protected from endonuclease degradation according to the DNase I digestion assay. After incubation with protoplasts and leaves, GFP was observed with confocal microscopy in plant cells. Western blot experiments confirmed GFP expression at the protein level. Toxicity assay showed PDMAEMA had a lower toxicity than PEI. These results showed that transient expression of pGFP was readily achieved in Arabidopsis thaliana and Nicotiana benthamiana. Notably, PDMAEMA showed lower cytotoxicity than PEI upon incubation with Nicotiana benthamiana leaves. PDMAEMA exhibited great potency for DNA delivery in plant cells. This work provides us with new ideas of more concise and more effective methods for plant transformation.

Rationally Driven Drug Nonradiative Decay via a Label-Free Polyprodrug Strategy to Renew Tumor Cascade Photothermal-Chemotherapy.

Drugs are frequently used for only chemotherapy that ignores their photophysical properties that potentially endow them with other therapeutic potency. Additionally, current photothermal-chemotherapy replies on the codelivery of drugs and photothermal agents, but their spatiotemporal delivery and precise release is unsatisfactory. Herein, label-free doxorubicin (DOX) polyprodrug nanoparticles (DPNs) are formulated from disulfide bonds-tethered DOX polyprodrug amphiphiles (PDMA-b-PDOXM). Benefiting from boosted nonradiative decay of high-density DOX, significant fluorescence quenching and photothermal effects are observed for DPNs without common photothermal agents. Upon cellular uptake and laser irradiation, the heat can promote lysosomal escape of DPNs into reductive cytosol, whereupon free DOX is released to activate chemotherapy and fluorescence, achieving rational cascade photothermal-chemotherapy. The current label-free polyprodrug strategy can make full use of drugs; it provides an alternative insight to extend the therapeutic domain of drugs.

Fast Broad-Spectrum Staining and Photodynamic Inhibition of Pathogenic Microorganisms by a Water-Soluble Aggregation-Induced Emission Photosensitizer.

Pathogenic microorganisms pose great challenges to public health, which is constantly urgent to develop extra strategies for the fast staining and efficient treatments. In addition, once bacteria form stubborn biofilm, extracellular polymeric substance (EPS) within biofilm can act as protective barriers to prevent external damage and inward diffusion of traditional antibiotics, which makes it frequently develop drug-resistant ones and even hard to treat. Therefore, it is imperative to develop more efficient methods for the imaging/detection and efficient inhibition of pathogenic microorganisms. Here, a water-soluble aggregation-induced emission (AIE)-active photosensitizer TPA-PyOH was employed for fast imaging and photodynamic treatment of several typical pathogens, such as S. aureus, methicillin-resistant Staphylococcus aureus, L. monocytogenes, C. albicans, and E. coli. TPA-PyOH was non-fluorescent in water, upon incubation with pathogen, positively charged TPA-PyOH rapidly adhered to pathogenic membrane, thus the molecular motion of TPA-PyOH was restricted to exhibit AIE-active fluorescence for turn-on imaging with minimal background. Upon further white light irradiation, efficient reactive oxygen species (ROS) was in-situ generated to damage the membrane and inhibit the pathogen eventually. Furthermore, S. aureus biofilm could be suppressed in vitro. Thus, water-soluble TPA-PyOH was a potent AIE-active photosensitizer for fast fluorescent imaging with minimal background and photodynamic inhibition of pathogenic microorganisms.

Photoacoustic Cavitation-Ignited Reactive Oxygen Species to Amplify Peroxynitrite Burst by Photosensitization-Free Polymeric Nanocapsules.

Photoacoustic (PA) technology can transform light energy into acoustic wave, which can be used for either imaging or therapy that depends on the power density of pulsed laser. Here, we report photosensitizer-free polymeric nanocapsules loaded with nitric oxide (NO) donors, namely NO-NCPs, formulated from NIR light-absorbable amphiphilic polymers and a NO-releasing donor, DETA NONOate. Controlled NO release and nanocapsule dissociation are achieved in acidic lysosomes of cancer cells. More importantly, upon pulsed laser irradiation, the PA cavitation can excite water to generate significant reactive oxygen species (ROS) such as superoxide radical (O2.- ), which further spontaneously reacts with the in situ released NO to burst highly cytotoxic peroxynitrite (ONOO- ) in cancer cells. The resultant ONOO- generation greatly promotes mitochondrial damage and DNA fragmentation to initiate programmed cancer cell death. Apart from PA imaging, PA cavitation can intrinsically amplify reactive species via photosensitization-free materials for promising disease theranostics.

Dual-Responsive Polyprodrug Nanoparticles with Cascade-Enhanced Magnetic Resonance Signals for Deep-Penetration Drug Release in Tumor Therapy.

Smart transformable nanocarriers are promising to treat deep-seated diseases but require adaptable diagnostic/imaging potency to reflect the morphology change and therapeutic feedback, yet their design and synthesis remains challenging. Herein, stimuli-responsive polyprodrug nanoparticles (SPNs) are formulated from the co-assembly of negatively charged corona and positively charged polyprodrug cores, exhibiting high loading content of camptothecin (CPT, ∼28.6 wt %) tethered via disulfide linkages in the core. SPNs are sequentially sensitive to tumor acidic condition and elevated reductive milieu in the cytosol for deep-penetration drug delivery. Upon accumulation at acidic tumor sites, SPNs dissociate to release smaller positively charged polyprodrug nanoparticles, which efficiently enter deep-seated tumor cells to trigger high-dosage parent CPT release in the reductive cytosolic milieu. Meanwhile, the polyprodrug cores of SPNs labeled with DTPA(Gd), a magnetic resonance imaging contrast agent, can trace the cascade degradation and biodistribution of SPNs as well as the resulting intracellular CPT release. The longitudinal relaxivity of SPNs increases stepwise in the above two processes. The size-switchable polyprodrug nanoparticles exhibit remarkable tumor penetration and noteworthy tumor inhibition in vitro and in vivo, which are promising for endogenously activated precision diagnostics and therapy.

Rational collaborative ablation of bacterial biofilms ignited by physical cavitation and concurrent deep antibiotic release.

Bacteria biofilm has extracellular polymeric substances to protect bacteria from external threats, which is a stubborn problem for human health. Herein, a kind of gasifiable nanodroplet is fabricated to ablate Staphylococcus aureus (S. aureus) biofilm. Upon NIR pulsed laser irradiation, the nanodroplets can gasify to generate destructive gas shockwave, which further potentiates initial acoustic cavitation effect, thus synergistically disrupting the protective biofilm and killing resident bacteria. More importantly, the gasification can further promote antibiotic release in deep biofilm for residual bacteria eradication. The nanodroplets not only exhibit deep biofilm penetration capacity and high potency to ablate biofilms, but also good biocompatibility without detectable side effects. In vivo mouse implant model indicates that the nanodroplets can accumulate at the S. aureus infected implant sites. Upon pulsed laser treatment, the nanodroplets efficiently eradicate bacteria biofilm in implanted catheter by synergistic contribution of gas shockwave-enhanced cavitation and deep antibiotic release. Current phase changeable nanodroplets with synergistic physical and chemical therapeutic modalities are promising to combat complex bacterial biofilms with drug resistance, which provides an alternative visual angle for biofilm inhibition in biomedicine.

In vivo photothermal inhibition of methicillin-resistant Staphylococcus aureus infection by in situ templated formulation of pathogen-targeting phototheranostics.

Bacterial infection has caused a serious threat to human public health. Methicillin-resistant Staphylococcus aureus (MRSA) is a representative drug-resistant bacterium, which is difficult to eradicate completely, resulting in high infection probability with severe mortality. Herein, pathogen-targeting phototheranostic nanoparticles, Van-OA@PPy, are developed for efficient elimination of MRSA infection. Van-OA@PPy nanoparticles are fabricated from the in situ templated formation of polypyrrole (PPy) in the presence of ferric ions (Fe3+) and a polymer template, hydrophilic poly(2-hydroxyethyl methacrylate-co-N,N-dimethyl acrylamide), P(HEMA-co-DMA). PPy nanoparticles are further coated with vancomycin conjugated oleic acid (Van-OA) to afford the resultant pathogen-targeting Van-OA@PPy. A high photothermal conversion efficiency of ∼49.4% is achieved. MRSA can be efficiently killed due to sufficient nanoparticle adhesion and fusion with MRSA, followed by photothermal therapy upon irradiation with an 808 nm laser. Remarkable membrane damage of MRSA is observed, which contributes greatly to the inhibition of MRSA infection. Furthermore, the nanoparticles have high stability and good biocompatibility without causing any detectable side effects. On the other hand, residual Fe3+ and PPy moieties in Van-OA@PPy endow the nanoparticles with magnetic resonance (MR) imaging and photoacoustic (PA) imaging potency, respectively. The current strategy has the potential to inspire further advances in precise diagnosis and efficient elimination of MRSA infection in biomedicine.

Cytosolic NQO1 Enzyme-Activated Near-Infrared Fluorescence Imaging and Photodynamic Therapy with Polymeric Vesicles.

The utilization of enzymes as a triggering module could endow responsive polymeric nanostructures with selectivity in a site-specific manner. On the basis of the fact that endogenous NAD(P)H:quinone oxidoreductase isozyme 1 (NQO1) is overexpressed in many types of tumors, we report on the fabrication of photosensitizer-conjugated polymeric vesicles, exhibiting synergistic NQO1-triggered turn-on of both near-infrared (NIR) fluorescence emission and a photodynamic therapy (PDT) module. For vesicles self-assembled from amphiphilic block copolymers containing quinone trimethyl lock-capped self-immolative side linkages and quinone-bridged photosensitizers (coumarin and Nile blue) in the hydrophobic block, both fluorescence emission and PDT potency are initially in the "off" state due to "double quenching" effects, that is, dye-aggregation-caused quenching and quinone-rendered PET (photoinduced electron transfer) quenching. After internalization into NQO1-positive vesicles, the cytosolic NQO1 enzyme triggers self-immolative cleavage of quinone linkages and fluorogenic release of conjugated photosensitizers, leading to NIR fluorescence emission turn-on and activated PDT. This process is accompanied by the transformation of vesicles into cross-linked micelles with hydrophilic cores and smaller sizes and triggered dual drug release, which could be directly monitored by enhanced magnetic resonance (MR) imaging for vesicles conjugated with a DOTA(Gd) complex in the hydrophobic bilayer. We further demonstrate that the above strategy could be successfully applied for activated NIR fluorescence imaging and tissue-specific PDT under both cellular and in vivo conditions.

Highly efficient singlet oxygen generation, two-photon photodynamic therapy and melanoma ablation by rationally designed mitochondria-specific near-infrared AIEgens.

Photosensitizers (PSs) with multiple characteristics, including efficient singlet oxygen (1O2) generation, cancer cell-selective accumulation and subsequent mitochondrial localization as well as near-infrared (NIR) excitation and bright NIR emission, are promising candidates for imaging-guided photodynamic therapy (PDT) but rarely concerned. Herein, a simple rational strategy, namely modulation of donor-acceptor (D-A) strength, for molecular engineering of mitochondria-targeting aggregation-induced emission (AIE) PSs with desirable characteristics including highly improved 1O2 generation efficiency, NIR emission (736 nm), high specificity to mitochondria, good biocompatibility, high brightness and superior photostability is demonstrated. Impressively, upon light irradiation, the optimal NIR AIE PS (DCQu) can generate 1O2 with efficiency much higher than those of commercially available PSs. The excellent two-photon absorption properties of DCQu allow two-photon fluorescence imaging of mitochondria and subsequent two-photon excited PDT. DCQu can selectively differentiate cancer cells from normal cells without the aid of extra targeting ligands. Upon ultralow-power light irradiation at 4.2 mW cm-2, in situ mitochondrial photodynamic activation to specifically damage cancer cells and efficient in vivo melanoma ablation are demonstrated, suggesting superior potency of the AIE PS in imaging-guided PDT with minimal side effects, which is promising for future precision medicine.

Fast surface immobilization of native proteins through catalyst-free amino-yne click bioconjugation.

Surface immobilization provides a useful platform for biosensing, drug screening, tissue engineering and other chemical and biological applications. However, some of the used reactions are inefficient and/or complicated, limiting their applications in immobilization. Herein, we use a spontaneous and catalyst-free amino-yne click bioconjugation to generate activated ethynyl group functionalized surfaces for fast immobilization of native proteins and cells. Biomolecules, such as bovine serum albumin (BSA), human IgG and a peptide of C(RGDfK), could be covalently immobilized on the surfaces in as short as 30 min. Notably, the bioactivity of the anchored biomolecules remains intact, which is verified by efficiently capturing target antibodies and cells from the bulk solutions. This strategy represents an alternative for highly efficient surface biofunctionalization.

Small-Molecule CSF1R Inhibitors as Anticancer Agents.

Persuasive evidence has been presented linking the infiltration of Tumor-Associated Macrophages (TAMs) with the driving force of tumorigenesis and in the suppression of antitumor immunity. In this context CSF1R, the cellular receptor for Colony Stimulating Factor-1 (CSF1) and Interleukin 34 (IL-34), occupies a central role in manipulating the behavior of TAMs and the dysregulation of CSF1R signaling has been implicated in cancer progression and immunosuppression in many specific cancers. Consequently, CSF1R kinase has been a target of great interest in cancer treatment and significant research efforts have focused on the development of smallmolecule CSF1R inhibitors. In this review, we highlight current progress on the development of these small molecule CSF1R inhibitors as anticancer agents. Special attention is paid to the compounds available in advanced clinical trials.

Author Correction: Mitochondria-specific drug release and reactive oxygen species burst induced by polyprodrug nanoreactors can enhance chemotherapy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.