Specific Activation of Photosensitizer with Extrinsic Enzyme for Precisive Photodynamic Therapy

Macrophage-engaging peptidic bispecific antibodies (pBsAbs) for immunotherapy via a facile bioconjugation strategy

Bispecific antibodies are artificial molecules that fuse two different antigen-binding sites of monoclonal antibodies into one single entity. They have emerged as a promising next-generation anticancer treatment. Despite the fascinating applications of bispecific antibodies, the design and production of bispecific antibodies remain tedious and challenging, leading to a long R&D process and high production costs. We herein report an unprecedented strategy to cyclise and conjugate tumour-targeting peptides on the surface of a monoclonal antibody to form a novel type of bispecific antibody, namely the peptidic bispecific antibody (pBsAb). Such design combines the merits of highly specific monoclonal antibodies and serum-stable cyclic peptides that endows an additional tumour-targeting ability to the monoclonal antibody for binding with two different antigens. Our results show that the novel pBsAb, which comprises EGFR-binding cyclic peptides and an anti-SIRP-α monoclonal antibody, could serve as a macrophage-engaging bispecific antibody to initiate enhanced macrophage-cancer cell interaction and block the "don't eat me" signal between CD47-SIRP-α, as well as promoting antibody-dependent cellular phagocytosis and 3D cell spheroid infiltration. These findings give rise to a new type of bispecific antibody and a new platform for the rapid generation of new bispecific antibodies for research and potential therapeutic uses.

Imaging and Downstaging Bladder Cancer with the 177Lu-Labeled Bioorthogonal Nanoprobe

Efforts on bladder cancer treatment have been shifting from extensive surgery to organ preservation in the past decade. To this end, we herein develop a multifunctional nanoagent for bladder cancer downstaging and bladder-preserving therapy by integrating mucosa penetration, reduced off-target effects, and internal irradiation therapy into a nanodrug. Specifically, an iron oxide nanoparticle was used as a carrier that was coated with hyaluronic acid (HA) for facilitating mucosa penetration. Dibenzocyclooctyne (DBCO) was introduced into the HA coating layer to react through bioorthogonal reaction with azide as an artificial receptor of bladder cancer cells, to improve the cellular internalization of the nanoprobe labeled with 177Lu. Through magnetic resonance imaging, the targeted imaging of both nonmuscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) was realized after intravesical instillation of the multifunctional probe, both NMIBC and MIBC were found downstaged, and the metastasis was inhibited, which demonstrates the potential of the multifunctional nanoprobe for bladder preservation in bladder cancer treatment.

β-Galactosidase-Triggered Photodynamic Elimination of Senescent Cells with a Boron Dipyrromethene-Based Photosensitizer

Senescence is a cellular response having physiological and reparative functions to preserve tissue homeostasis and suppress tumor growth. However, the accumulation of senescent cells would cause deleterious effects that lead to age-related dysfunctions and cancer progression. Hence, selective detection and elimination of senescent cells are crucial yet remain a challenge. A β-galactosidase (β-gal)-activated boron dipyrromethene (BODIPY)-based photosensitizer (compound 1) is reported here that can selectively detect and eradicate senescent cells. It contains a galactose moiety connected to a pyridinium BODIPY via a self-immolative nitrophenylene linker, of which the photoactivity is effectively quenched. Upon interactions with the senescence-associated β-gal, it undergoes enzymatic hydrolysis followed by self-immolation, leading to the release of an activated BODIPY moiety by which the fluorescence emission and singlet oxygen generation are restored. The ability of 1 to detect and eliminate senescent cells is demonstrated in vitro and in vivo, using SK-Mel-103 tumor-bearing mice treated with senescence-inducing therapy. The results demonstrate that 1 can be selectively activated in senescent cells to trigger a robust senolytic effect upon irradiation. This study breaks new ground in the design and application of new senolytic agents based on photodynamic therapy.

A Novel Boron Dipyrromethene-Erlotinib Conjugate for Precise Photodynamic Therapy against Liver Cancer

Photodynamic Therapy (PDT) is recognized for its exceptional effectiveness as a promising cancer treatment method. However, it is noted that overexposure to the dosage and sunlight in traditional PDT can result in damage to healthy tissues, due to the low tumor selectivity of currently available photosensitizers (PSs). To address this challenge, we introduce herein a new strategy where the small molecule-targeted agent, erlotinib, is integrated into a boron dipyrromethene (BODIPY)-based PS to form conjugate 6 to enhance the precision of PDT. This conjugate demonstrates optical absorption, fluorescence emission, and singlet oxygen generation efficiency comparable to the reference compound 7, which lacks erlotinib. In vitro studies reveal that, after internalization, conjugate 6 predominantly accumulates in the lysosomes of HepG2 cells, exhibiting significant photocytotoxicity with an IC50 value of 3.01 µM. A distinct preference for HepG2 cells over HELF cells is observed with conjugate 6 but not with compound 7. In vivo experiments further confirm that conjugate 6 has a specific affinity for tumor tissues, and the combination treatment of conjugate 6 with laser illumination can effectively eradicate H22 tumors in mice with outstanding biosafety. This study presents a novel and potential PS for achieving precise PDT against cancer.

NQO1-activated multifunctional theranostic probe for imaging-guided mitochondria-targeted photodynamic therapy and boosting immunogenic cell death

NAD(P)H: quinine oxidoreductase (NQO1) is overexpressed in many types of cancer cells, and have been used as a biomarker for cancer diagnosis and targeted therapy. The development of activatable theranostic agents is highly desirable for precise cancer diagnosis and therapy. Herein, a NQO1-activated near-infrared multifunctional theranostic probe I-HCy-Q is successfully developed for imaging guided photodynamic therapy. The NIR fluorescence (λex/em = 685/703 nm) and capacity of reactive oxygen species generation are sensitive controllable by the level of NQO1, the linear detection range of NQO1 and limit of detection are 0.05-1.5 μg/mL and 5.66 ng/mL, respectively. On the one hand, I-HCy-Q can monitor the activity of NQO1 and distinguish the NQO1 positive cancer cells; on the other hand, the capacity of mitochondria-targeted photodynamic therapy makes I-HCy-Q an effective inducer of apoptosis and immunogenic cell death. Attribute to its complementary advantages, I-HCy-Q holds potential for the imaging and treatment of tumors in complex organisms.

Theranostic Fluorescent Probes

The ability to gain spatiotemporal information, and in some cases achieve spatiotemporal control, in the context of drug delivery makes theranostic fluorescent probes an attractive and intensely investigated research topic. This interest is reflected in the steep rise in publications on the topic that have appeared over the past decade. Theranostic fluorescent probes, in their various incarnations, generally comprise a fluorophore linked to a masked drug, in which the drug is released as the result of certain stimuli, with both intrinsic and extrinsic stimuli being reported. This release is then signaled by the emergence of a fluorescent signal. Importantly, the use of appropriate fluorophores has enabled not only this emerging fluorescence as a spatiotemporal marker for drug delivery but also has provided modalities useful in photodynamic, photothermal, and sonodynamic therapeutic applications. In this review we highlight recent work on theranostic fluorescent probes with a particular focus on probes that are activated in tumor microenvironments. We also summarize efforts to develop probes for other applications, such as neurodegenerative diseases and antibacterials. This review celebrates the diversity of designs reported to date, from discrete small-molecule systems to nanomaterials. Our aim is to provide insights into the potential clinical impact of this still-emerging research direction.

Enhancing Fractionated Cancer Therapy: A Triple-Anthracene Photosensitizer Unleashes Long-Persistent Photodynamic and Luminous Efficacy

Conventional photodynamic therapy (PDT) is often limited in treating solid tumors due to hypoxic conditions that impede the generation of reactive oxygen species (ROS), which are critical for therapeutic efficacy. To address this issue, a fractionated PDT protocol has been suggested, wherein light irradiation is administered in stages separated by dark intervals to permit oxygen recovery during these breaks. However, the current photosensitizers used in fractionated PDT are incapable of sustaining ROS production during the dark intervals, leading to suboptimal therapeutic outcomes (Table S1). To circumvent this drawback, we have synthesized a novel photosensitizer based on a triple-anthracene derivative that is designed for prolonged ROS generation, even after the cessation of light exposure. Our study reveals a unique photodynamic action of these derivatives, facilitating the direct and effective disruption of biomolecules and significantly improving the efficacy of fractionated PDT (Table S2). Moreover, the existing photosensitizers lack imaging capabilities for monitoring, which constraints the fine-tuning of irradiation parameters (Table S1). Our triple-anthracene derivative also serves as an afterglow imaging agent, emitting sustained luminescence postirradiation. This imaging function allows for the precise optimization of intervals between PDT sessions and aids in determining the timing for subsequent irradiation, thus enabling meticulous control over therapy parameters. Utilizing our novel triple-anthracene photosensitizer, we have formulated a fractionated PDT regimen that effectively eliminates orthotopic pancreatic tumors. This investigation highlights the promise of employing long-persistent photodynamic activity in advanced fractionated PDT approaches to overcome the current limitations of PDT in solid tumor treatment.

NQO-1 activatable NIR photosensitizer for visualization and selective killing of breast cancer cells

The diagnosis and treatment of breast cancer is of immense importance in improving patient outcomes. The biological marker NAD(P)H:quinone oxidoreductase 1 was utilized to design BrCyS-Q, a near-infrared activatable photosensitizer for breast cancer. BrCyS-Q was successfully employed to diagnose breast cancer cells using fluorescence and photodynamic inhibition. The findings of this research may offer novel insights for the diagnosis and treatment of clinical breast cancer via photodynamic therapy.

Chemical Modification of Cytochrome C for Acid-Responsive Intracellular Apoptotic Protein Delivery for Cancer Eradication

Delivering bioactive proteins into cells without carriers presents significant challenges in biomedical applications due to limited cell membrane permeability and the need for targeted delivery. Here, we introduce a novel carrier-free method that addresses these challenges by chemically modifying proteins with an acid-responsive cell-penetrating peptide (CPP) for selective intracellular delivery within tumours. Cytochrome C, a protein known for inducing apoptosis, served as a model for intracellular delivery of therapeutic proteins for cancer treatment. The CPP was protected with 2,3-dimethyl maleic anhydride (DMA) and chemically conjugated onto the protein surface, creating an acid-responsive protein delivery system. In the acidic tumour microenvironment, DMA deprotects and exposes the positively charged CPP, enabling membrane penetration. Both in vitro and in vivo assays validated the pH-dependent shielding mechanism, demonstrating the modified cytochrome C could induce apoptosis in cancer cells in a pH-selective manner. These findings provide a promising new approach for carrier-free and tumour-targeted intracellular delivery of therapeutic proteins for a wide range of potential applications.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

Fidelity-oriented fluorescence imaging probes for beta-galactosidase: From accurate diagnosis to precise treatment

Beta-galactosidase (β-gal), a typical glycosidase catalyzing the hydrolysis of glycosidic bonds, is regarded as a vital biomarker for cell senescence and cancer occurrence. Given the advantages of high spatiotemporal resolution, high sensitivity, non-invasiveness, and being free of ionizing radiations, fluorescent imaging technology provides an excellent choice for in vivo imaging of β-gal. In this review, we detail the representative biotech advances of fluorescence imaging probes for β-gal bearing diverse fidelity-oriented improvements to elucidate their future potential in preclinical research and clinical application. Next, we propose the comprehensive design strategies of imaging probes for β-gal with respect of high fidelity. Considering the systematic implementation approaches, a range of high-fidelity imaging-guided theragnostic are adopted for the individual β-gal-associated biological scenarios. Finally, current challenges and future trends are proposed to promote the next development of imaging agents for individual and specific application scenarios.

Tumor Stimulus-Activatable Pretheranostic Agent: One Key to Three Locks

The uncontrollable distribution of antitumor agents remains a large obstacle for specific and efficient cancer theranostics; thus, efficient construction of tumor-specific systems is highly desirable. In this work, a general design of tumor stimulus-activatable pretheranostic agents was put forward via a series of structures-tunable triphenylamine derivatives (TPA-2T-FSQ, TPA-2T-BSZ, and TPA-2T-ML) with phenothiazine, benzothiazine, and thiomorpholine as identifying groups of hypochlorite (HClO), respectively. Notably, the sulfur atom in phenothiazine of TPA-2T-FSQ was more easily oxidized to sulfoxide groups by HClO, transforming into an electron acceptor to form an excellent push-pull electronic system, which was beneficial to a large redshift of absorbance and emission wavelengths. Based on this, TPA-2T-FSQ resorted to a key of overexpressed HClO in the tumor to open "three locks", viz, NIR fluorescence, photothermal, and photoacoustic signals for multimodal diagnostic and treatment of the tumor. This study provided an elegant design to adopt tumor stimulus-triggerable pretheranostic for improving theranostic accuracy and efficiency, which was regarded as a promising candidate for precision medicine.

Enzyme and MicroRNA Dual-Regulated Photodynamic Molecular Beacons for Cell-Selective Amplification of Antitumor Efficacy

Photodynamic molecular beacons (PMBs) are highly appealing for activatable photodynamic therapy (PDT), but their applications are hindered by limited therapeutic efficacy. Here, by molecular engineering of enzyme-responsive units in the loop region of DNA-based PMBs, we present for the first time the modular design of an enzyme/microRNA dual-regulated PMB (D-PMB) to achieve cancer-cell-selective amplification of PDT efficacy. In the design, the "inert" photosensitizers in D-PMB could be repeatedly activated in the presence of both tumor-specific enzyme and miRNA, leading to amplified generation of cytotoxic singlet oxygen species and therefore enhanced PDT efficacy in vitro and in vivo. By contrast, low photodynamic activity could be observed in healthy cells, as D-PMB activation has been largely avoided by the dual-regulatable design. This work presents a cooperatively activated PDT strategy, which enables enhanced therapeutic efficacy with improved tumor-specificity and thus conceptualizes an approach to expand the repertoire of designing smart tumor treatment modality.

Rational Design of Mesoporous Coordination Polymer Nanophotosensitizers for Photodynamic Tumor Ablation

Effective clinical practice of precise photodynamic therapy (PDT) is severely impeded by the inherent drawbacks and aggregation propensity of conventional photosensitizers. An all-in-one approach is highly desired to optimize structural features, photophysical properties, and pharmacokinetic behaviors of photosensitizers. Herein, we have fabricated mesoporous boron dipyrromethene-bridged coordination polymer nanophotosensitizers (BCP-NPs) for high-performance PDT via a unique solvent-assisted assembly strategy. Distinctive photophysical and structural characteristics of BCP-NPs confer enhanced photodynamic activities, together with high cellular uptake and ultrahigh stability. Moreover, BCP-NPs showed excellent tumor accumulation and prolonged tumor retention, achieving eradication of the triple-negative breast cancer (TNBC) model under low-power-density LED irradiation. This work has provided a valuable paradigm for the construction of mesoporous photoactive nanomaterials for biophotonic applications.

Esterase-Activated, pH-Responsive, and Genetically Targetable Nano-Prodrug for Cancer Cell Photo-Ablation

Activatable prodrugs have drawn considerable attention for cancer cell ablation owing to their high specificity in drug delivery systems. However, phototheranostic prodrugs with dual organelle-targeting and synergistic effects are still rare due to low intelligence of their structures. Besides, the cell membrane, exocytosis, and diffusional hindrance by the extracellular matrix reduce drug uptake. Moreover, the up-regulation of heat shock protein and short singlet-oxygen lifetime in cancer cells hamper photo-ablation efficacy, especially in the mono-therapeutic model. To overcome those obstacles, we prepare an esterase-activated DM nano-prodrug, which is conjugated by diiodine-substituted fluorogenic malachite green derivative (MG-2I) and phototherapeutic agent DPP-OH via hydrolyzable ester linkage, having pH-responsiveness and genetically targetable activity for dual organelles-targeting to optimize photo-ablation efficacy. The DM nanoparticles (NPs) present improved pH-responsive photothermal/photodynamic property by the protonation of diethylaminophenyl units in acidic environment. More importantly, the MG-2I and DPP-OH moieties can be released from DM nano-prodrug through overexpressed esterase; then specifically target lysosomes and mitochondria in CT-26 Mito-FAP cells. Hence, near-infrared DM NPs can trigger parallel damage in dual-organelles with strong fluorescence and effective phototoxicity, thus inducing serious mitochondrial dysfunction and apoptotic death, showing excellent photo-ablation effect based on esterase-activated, pH-responsive, and genetically targetable activities.

Selective photodynamic eradication of senescent cells with a β-galactosidase-activated photosensitiser

A β-galactosidase-responsive photosensitiser has been designed and synthesised. It contains a galactosyl substrate, a boron dipyrromethene-based photosensitising unit and a black hole quencher 2 connected via an AB₂-type self-immolative linker. This novel photosensitiser can be selectively activated by the senescence-associated β-galactosidase in senescent cells, leading to restoration in fluorescence emission and effective killing of the cells via photodynamic action.

Bioabsorbable nano-micelle hybridized hydrogel scaffold prevents postoperative melanoma recurrence

The residual and scattered small tumor tissue or cells after surgery are the main reason for tumor recurrence. Chemotherapy has a powerful ability to eradicate tumors but always accompanied by serious side effects. In this work, tissue-affinity mercapto gelatin (GelS) and dopamine-modified hyaluronic acid (HAD) were employed to fabricate a hybridized cross-linked hydrogel scaffold (HG) by multiple chemical reactions, which could integrate the doxorubicin (DOX) loaded reduction-responsive nano-micelle (PP/DOX) into this scaffold via click reaction to obtain the bioabsorbable nano-micelle hybridized hydrogel scaffold (HGMP). With the degradation of HGMP, PP/DOX was slowly released and formed targeted PP/DOX with degraded gelatin fragments as target molecules, which increased the intracellular accumulation, and inhibited the aggregation of B16F10 cells in vitro. In mouse models, HGMP absorbed the scattered B16F10 cells and released targeted PP/DOX to suppress tumorigenesis. For another, implantation of HGMP at the surgical site reduced the recurrence rate of postoperative melanoma and inhibited the growth of recurrent tumors. Meanwhile, HGMP significantly relieved the damage of free DOX to hair follicle tissue. This bioabsorbable nano-micelle hybridized hydrogel scaffold provided a valuable strategy for adjuvant therapy after tumor surgery.

Guanidine Additive Enabled Intermolecular ortho-Phthalaldehyde-Amine-Thiol Three-Component Reactions for Modular Constructions

Recently, ortho-phthalaldehyde (OPA) is experiencing a renascence for the modification of proteins and peptides through OPA-amine two-component reactions for bioconjugation and intramolecular OPA-amine-thiol three-component reactions for cyclization. Historically, small thiol molecules were used in large excess to allow for the intermolecular OPA-amine-thiol reaction forming 1-thio-isoindole derivatives. In this study, we discovered that guanidine could serve as an effective additive to switch the intermolecular OPA-amine-thiol three-component reaction to a stoichiometric process and enable the modular construction of peptide-peptide, and peptide-drug conjugate structures. Thus, 12 model peptide-peptide conjugates have been synthesized from unprotected peptides featuring all proteinogenic residues. Besides, 6 peptide-drug conjugates have been prepared in one step, with excellent conversions and isolated yields. In addition, a conjugate product has been further functionalized by utilizing a premodified OPA derivative, demonstrating the versatility and flexibility of this reaction.

Recent Progress in Carrier-Free Nanomedicine for Tumor Phototherapy

Safe and effective strategies are urgently needed to fight against the life-threatening diseases of various cancers. However, traditional therapeutic modalities, such as radiotherapy, chemotherapy and surgery, exhibit suboptimal efficacy for malignant tumors owing to the serious side effects, drug resistance and even relapse. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are emerging therapeutic strategies for localized tumor inhibition, which can produce a large amount of reactive oxygen species (ROS) or elevate the temperature to initiate cell death by non-invasive irradiation. In consideration of the poor bioavailability of phototherapy agents (PTAs), lots of drug delivery systems have been developed to enhance the tumor targeted delivery. Nevertheless, the carriers of drug delivery systems inevitably bring biosafety concerns on account of their metabolism, degradation, and accumulation. Of note, carrier-free nanomedicine attracts great attention for clinical translation with synergistic antitumor effect, which is characterized by high drug loading, simplified synthetic method and good biocompatibility. In this review, the latest advances of phototherapy with various carrier-free nanomedicines are summarized, which may provide a new paradigm for the future development of nanomedicine and tumor precision therapy.

A pH-Responsive Drug Delivery System Based on Conjugated Polymer for Effective Synergistic Chemo-/Photodynamic Therapy

Stimuli-responsive drug release and photodynamic therapy (PDT) have aroused extensive attention for their enormous potential in antitumor treatment. pH-responsive drug delivery systems (PFE-DOX-1 and PFE-DOX-2) based on water-soluble conjugated polymers were constructed in this work for high-performance synergistic chemo-/PDT therapy, in which the anticancer drug doxorubicin (DOX) is covalently attached to the side chains of the conjugated polymers via acid-labile imine and acylhydrazone bonds. Concurrently, the intense fluorescence of poly(fluorene-co-ethynylene) (PFE) is effectively quenched due to the energy/electron transfer (ET) between the PFE-conjugated backbone and DOX. Effective pH-responsive drug release from PFE-DOX-2 is achieved by the cleavage of acylhydrazone linkages in the acidic tumor intracellular microenvironment. Additionally, the drug release process can be monitored by the recovered fluorescence of conjugated polymers. Furthermore, the conjugated polymers can produce reactive oxygen species (ROS) under light irradiation after drug release in an acidic environment, which prevents possible phototoxicity to normal tissues. It is noted that PFE-DOX-2 demonstrates remarkable antitumor cell performance, which is attributed to its efficient cell uptake and powerful synergistic chemo-/PDT therapeutic effectiveness. This report thus provides a promising strategy for in vivo anticancer treatment with the construction of a stimuli-responsive multifunctional drug delivery system.

A tetrazine-responsive isonitrile-caged photosensitiser for site-specific photodynamic therapy

We report herein a versatile and efficient bioorthogonal strategy to actualise targeted delivery and site-specific activation of photosensitisers for precise antitumoural photodynamic therapy. The strategy involved the use of an isonitrile-caged distyryl boron dipyrromethene-based photosensitiser, labelled as NC-DSBDP, of which the photoactivities could be specifically activated upon conversion of the meso ester substituent to carboxylate initiated by the [4 + 1] cycloaddition with a tetrazine derivative. By using two tetrazines conjugated with a galactose moiety or the GE11 peptide, labelled as gal-Tz and GE11-Tz, we could selectively label the cancer cells overexpressed with the asialoglycoprotein receptor and the epidermal growth factor receptor respectively. Upon encountering the internalised NC-DSBDP, these tetrazines triggered the "ester-to-carboxylate" transformation of this compound, activating its fluorescence and reactive oxygen species generation inside the target cells. The bioorthogonal activation was also demonstrated in vivo, leading to effective photo-eradication of the tumour in nude mice.

Different Influences of Biotinylation and PEGylation on Cationic and Anionic Proteins for Spheroid Penetration and Intracellular Uptake to Cancer Cells

To better understand the effects of PEGylation and biotinylation on the delivery efficiency of proteins, the cationic protein lysozyme (LZ) and anionic protein bovine serum albumin (BSA) were chemically conjugated with poly(ethylene glycol) (PEG) and biotin-PEG to primary amine groups of proteins using N-hydroxysuccinimide reactions. Four types of protein conjugates were successfully prepared: PEGylated LZ (PEG-LZ), PEGylated BSA (PEG-BSA), biotin-PEG-conjugated LZ (Bio-PEG-LZ), and biotin-PEG-conjugated BSA (Bio-PEG-BSA). PEG-LZ and Bio-PEG-LZ exhibited a lower intracellular uptake than that of LZ in A549 human lung cancer cells (in a two-dimensional culture). However, Bio-PEG-BSA showed significantly improved intracellular delivery as compared to that of PEG-BSA and BSA, probably because of favorable interactions with cells via biotin receptors. For A549/fibroblast coculture spheroids, PEG-LZ and PEG-BSA exhibited significantly decreased tissue penetration as compared with that of unmodified proteins. However, Bio-PEG-BSA showed tissue penetration comparable to that of unmodified BSA. In addition, citraconlyated LZ (Cit-LZ) showed reduced spheroid penetration as compared to that of LZ, probably owing to a decrease in protein charge. Taken together, chemical conjugation of targeting ligands-PEG to anionic proteins could be a promising strategy to improve intracellular delivery and in vivo activity, whereas modifications of cationic proteins should be more delicately designed.

Aptamer-Gold Nanocage Composite for Photoactivated Immunotherapy

Immune checkpoint blockade (ICB) has been hailed as the hope for conquering cancer as ICB could produce a significant and durable response to tumor cells. However, the high cost and severe side effects of ICB drugs limited their application for further anticancer therapy. Here, we developed a photoactivated immunotherapy nanoplatform (Apt@AuNC). This nanoplatform could target tumor tissues via enhanced penetration retention (EPR) effect and the aptamer (Apt) could be released from Apt@AuNC in tumor sites via illumination. The immune system in the tumor area was then activated after the combination of Apt and PD-1 protein. The heat generated from AuNC was able to continue killing tumor cells. This nanoplatform could not only achieve the precise immunotherapy but also significantly facilitate the anticancer efficacy.

A novel furo[3,2-c]pyridine-based AIE photosensitizer for specific imaging and photodynamic ablation of Gram-positive bacteria

An Rh-catalyzed tandem reaction was performed to construct an AIE-active furo[2,3-c]pyridine-based photosensitizer, named LIQ-TF. LIQ-TF showed near-infrared emission with high quantum yield, and high ¹O₂ and ˙OH generation efficiency, and could be used for specific imaging and photodynamic ablation of Gram-positive bacteria in vitro and in vivo, showing great potential for combating multiple drug-resistant bacteria.

Enzyme activatable photodynamic therapy agents targeting melanoma

A tyrosinase activatable photosensitizer is developed with selective phototoxicity to melanoma cells.