Natural-Origin Hypocrellin-HSA Assembly for Highly Efficient NIR Light-Responsive Phototheranostics against Hypoxic Tumors

A glutathione responsive photosensitizer based on hypocrellin B for photodynamic therapy

As a typical natural photosensitizer, hypocrellin B (HB) offers the advantages of high molar extinction coefficient, high phototoxicity, low dark toxicity, and fast metabolism in vivo. However, the lack of tumor specificity hinders its clinical applications. Herein, we designed and synthesized a glutathione (GSH) responsive photosensitizer based on HB. The 7 - nitro - 2,1,3 - benzoxadiazole (NBD) covalently connected to HB not only served as a fluorescence quenching group but also as a GSH activating group. The photosensitizer HB-NBD showed almost no fluorescence and singlet oxygen generation as a result of the photoinduced electron transfer between HB and NBD. The designed photosensitizer HB-NBD can be activated by GSH in solutions and cancer cells, and then obtain recuperative fluorescence and photosensitive activity.

Molecular Nanoarchitectonics of Natural Photosensitizers and Their Derivatives Nanostructures for Improved Photodynamic Therapy

Natural photosensitizers (PSs) and their derivatives have drawn ever-increasing attention in photodynamic therapy (PDT) for their wild range of sources, desirable biocompatibility, and good photosensitivity. Nevertheless, many factors such as poor solubility, high body clearance rate, limited tumor targeting ability, and short excitation wavelengths severely hinder their applications in efficient PDT. In recent years, fabricating nanostructures by utilizing molecular assembly technique is proposed to solve these problems. This technique is easy to put into effect, and the assembled nanostructures could improve the physical properties of the PSs so as to meet the requirement of PDT. In this concept, we focus on the construction of natural PSs and their derivatives nanostructures through molecular assembly technique to enhance PDT efficacy (Figure 1). Furthermore, current challenges and future perspectives of natural PSs and their derivatives for efficient PDT are discussed.

The future of plant based green carbon dots as cancer Nanomedicine: From current progress to future Perspectives and beyond

BACKGROUND

The emergence of carbon dots (CDs) as anticancer agents had sparked a transformation in cancer research and treatment strategies. These fluorescent CDs, initially introduced in the early 2000 s, possess exceptional biocompatibility, tunable fluorescence, and surface modification capabilities, positioning them as promising tools in biomedical applications.

AIM OF REVIEW

The review encapsulates the transformative trajectory of green CDs as future anticancer nanomedicine, poised to redefine the strategies employed in the ongoing fight against cancer.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The versatility of CDs was rooted in their various synthesis approaches and sustainable strategies, enabling their adaptability for diverse therapeutic uses. In vitro studies had showcased CDs' selective cytotoxicity against cancer cells while sparing healthy counterparts, forming the basis for targeted therapeutic potential. This selectivity had been attributed to the reactive oxygen species (ROS) generation, which opened avenues for targeted interventions. The role of CDs in combination therapies, synergizing with chemotherapy, radiotherapy, and targeted approaches was then investigated to heighten their anticancer efficacy. Notably, in vivo studies highlight CDs' remarkable biocompatibility and minimal side effects, endorsing their translational promise. Integration with conventional cancer treatments such as chemotherapy, radiotherapy, and immunotherapy amplified the versatility and effectiveness of CDs. The exploration of CDs' applications in photo-induced treatments further solidified their significance, positioning them as photosensitizers (PS) in photodynamic therapy (PDT) and photothermal agents (PA) in photothermal therapy (PTT). In PDT, CDs triggered the generation of ROS upon light exposure, facilitating cancer cell elimination, while in PTT, they induced localized hyperthermia within cancer cells, enhancing therapeutic outcomes. In vitro and in vivo investigations validated CDs' efficacy in PDT and PTT, affirming their potential for integration into combination therapies. Looking ahead, the future of CDs in anticancer treatment encompasses bioavailability, biocompatibility, synergistic treatments, tumor targeting, artificial intelligence (AI) and robotics integration, personalized medicine, and clinical translation. This transformative odyssey of CDs as future anticancer agents is poised to redefine the paradigm of cancer treatment strategies.

NIR-II xanthene dyes with structure-inherent bacterial targeting for efficient photothermal and broad-spectrum antibacterial therapy

Development of novel broad-spectrum sterilization is an efficient strategy that can overcome drug resistance and avoid antibiotics abuse toward bacterial-infected diseases. Photothermal therapy (PTT) in the second near-infrared (NIR-II) therapeutic window with an increased tissue penetration and elevated maximal permissible exposure has attracted considerable attention in antibacterial applications. However, the lack of bacterial-targeted photothermal agents limits their further development. Herein, we developed three xanthene derivatives (CNs) with intense light harvesting ability around 1180 nm. Their bulky planar conformations facilitated the formation of H-aggregates with outstanding photothermal conversion ability and good photostability in the NIR-II therapeutic bio window. By manipulating side chains of CNs, their liposomes exhibited different surface charges, ranging from negative to positive. Remarkably, the intermolecular hydrogen bonding of CN3 dimer drived the positively charged xanthene skeleton exposed to the periphery, which endowed it natural bacterial targeting potency. Therefore, CN3 possessed a good NIR-II photothermal and broad-spectrum sterilization against Gram-positive and Gram-negative bacteria. The photothermal antibacterial activities for S. aureus and E. coli were 99.4% and 99.2%, respectively, promoting significant wound healing in bacteria-infected mice with superior biocompatibility. This structure-inherent bacterial targeting strategy as a proof-of-concept shows an efficient broad-spectrum bacterial inactivation, indicating more encouraging NIR-II photothermal antibacterial therapy. STATEMENT OF SIGNIFICANCE: Photothermal therapy (PTT) in the second near-infrared region (NIR-II, 1000-1700 nm) enables the treatment of deep inflammation more satisfactory due to higher tissue penetration depth. In this work, three new NIR-II xanthene derivatives (CNs) with intense light harvesting ability around 1180 nm were developed. CNs showed typical H-aggregated performance with bulky planar conformations and outstanding photothermal conversion ability. Density functional theory calculations revealed that the intermolecular hydrogen bonding of CN3 dimer drived the exposure of positively charged xanthene skeleton to periphery of dimer. Therefore, CN3 NPs possessed natural bacterial targeting potency and excellent NIR-II photothermal and broad-spectrum sterilization, and so as to significantly promote the wound healing of Gram-positive / negative bacteria infected mice.

Recent Advances of Photoactive Near-Infrared Carbon Dots in Cancer Photodynamic Therapy

Photodynamic therapy (PDT) is a treatment that employs exogenously produced reactive oxygen species (ROS) to kill cancer cells. ROS are generated from the interaction of excited-state photosensitizers (PSs) or photosensitizing agents with molecular oxygen. Novel PSs with high ROS generation efficiency is essential and highly required for cancer photodynamic therapy. Carbon dots (CDs), the rising star of carbon-based nanomaterial family, have shown great potential in cancer PDT benefiting from their excellent photoactivity, luminescence properties, low price, and biocompatibility. In recent years, photoactive near-infrared CDs (PNCDs) have attracted increasing interest in this field due to their deep therapeutic tissue penetration, superior imaging performance, excellent photoactivity, and photostability. In this review, we review recent progress in the designs, fabrication, and applications of PNCDs in cancer PDT. We also provide insights of future directions in accelerating the clinical progress of PNCDs.

Structural modification of NIR-II fluorophores for angiography beyond 1300 nm: Expanding the xanthene universe

Fluorescence bioimaging via the second near-infrared (NIR-II) window can provide precise images with a low background signal due to attenuated absorption and scattering in biological tissues. However, it is challenging to realize organic fluorophores' absorption/emission wavelength beyond 1300 nm depending on their intrinsic emission of monomers. Reducing parasitic aggregation caused quenching (ACQ) effect is expected as an efficient strategy to achieve fluorescence bioimaging in an ideal region. Herein, two NIR-II xanthene fluorophores (CM1 and CM2) with different side chains on identical skeletons were synthesized. Besides, their corresponding assemblies (CM1 NPs and CM2 NPs) were subsequently prepared, which exhibited distinct spectroscopic properties. Notably, CM2 NPs exhibited a significantly reduced ACQ effect with maximal absorption/emission extended to 1235/1250 nm. Molecular dynamics simulations revealed that intermolecular hydrogen bond, π-π interaction, and CH-π interaction of CM2 were essential for the reduced ACQ effect. In vivo hindlimb angiography showed that CM2 NPs could distinguish the neighboring artery and vein in high resolution. Besides, CM2 NPs could achieve angiography beyond 1300 nm and even resolve capillaries as small as 0.23 mm. This study provides a new strategy for reducing the ACQ effect by controlling different side chains of NIR-II xanthene dyes for angiography beyond 1300 nm.

Recent Developments in Heteroatom/Metal-Doped Carbon Dot-Based Image-Guided Photodynamic Therapy for Cancer

Carbon nanodots (CNDs) are advanced nanomaterials with a size of 2-10 nm and are considered zero-dimensional carbonaceous materials. CNDs have received great attention in the area of cancer theranostics. The majority of review articles have shown the improvement of CNDs for use in cancer therapy and bioimaging applications. However, there is a minimal number of consolidated studies on the currently developed doped CNDs that are used in various ways in cancer therapies. Hence, in this review, we discuss the current developments in different types of heteroatom elements/metal ion-doped CNDs along with their preparations, physicochemical and biological properties, multimodal-imaging, and emerging applications in image-guided photodynamic therapies for cancer.

Contrasting regulation of live Bacillus cereus No.1 and its volatiles on Shiraia perylenequinone production

BACKGROUND

Fungal perylenequinones (PQs) are a class of photoactivated polyketide mycotoxins produced by plant-associated fungi. Hypocrellins, the effective anticancer photodynamic therapy (PDT) agents are main bioactive PQs isolated from a bambusicolous Shiraia fruiting bodies. We found previously that bacterial communities inhabiting fungal fruiting bodies are diverse, but with unknown functions. Bacillus is the most dominant genus inside Shiraia fruiting body. To understand the regulation role of the dominant Bacillus isolates on host fungus, we continued our work on co-culture of the dominant bacterium B. cereus No.1 with host fungus Shiraia sp. S9 to elucidate bacterial regulation on fungal hypocrellin production.

RESULTS

Results from "donut" plate tests indicated that the bacterial culture could promote significantly fungal PQ production including hypocrellin A (HA), HC and elsinochrome A-C through bacterial volatiles. After analysis by gas chromatograph/mass spectrometer and confirmation with commercial pure compounds, the volatiles produced by the bacterium were characterized. The eliciting roles of bacterial volatile organic compounds (VOCs) on HA production via transcriptional regulation of host Shiraia fungus were confirmed. In the established submerged bacterial volatile co-culture, bacterial volatiles could not only promote HA production in the mycelium culture, but also facilitate the release of HA into the medium. The total production of HA was reached to 225.9 mg/L, about 1.87 times that of the fungal mono-culture. In contrast, the live bacterium suppressed markedly fungal PQ production in both confrontation plates and mycelium cultures by direct contact. The live bacterium not only down-regulated the transcript levels of HA biosynthetic genes, but also degraded extracellular HA quickly to its reductive product.

CONCLUSION

Our results indicated that bacterial volatile release could be a long-distance signal to elicit fungal PQ production. Biodegradation and inhibition by direct contact on fungal PQs were induced by the dominate Bacillus to protect themselves in the fruiting bodies. This is the first report on the regulation of Bacillus volatiles on fungal PQ production. These findings could be helpful for both understanding the intimate fungal-bacterial interactions in a fruiting body and establishing novel cultures for the enhanced production of bioactive PQs.

Rapid Degradation of Rhodamine B through Visible-Photocatalytic Advanced Oxidation Using Self-Degradable Natural Perylene Quinone Derivatives-Hypocrellins

Hypocrellins (HYPs) are natural perylene quinone derivatives from Ascomycota fungi. Based on the excellent photosensitization properties of HYPs, this work proposed a photocatalytic advanced oxidation process (PAOP) that uses HYPs to degrade rhodamine B (RhB) as a model organic pollutant. A synergistic activity of HYPs and H2O2 (0.18 mM of HYPs, 0.33% w/v of H2O2) was suggested, resulting in a yield of 82.4% for RhB degradation after 60 min under visible light irradiation at 470−475 nm. The principle of pseudo-first-order kinetics was used to describe the decomposition reaction with a calculated constant (k) of 0.02899 min−1 (R2 = 0.983). Light-induced self-degradation of HYPs could be activated under alkaline (pH > 7) conditions, promising HYPs as an advanced property to alleviate the current dilemma of secondary pollution by synthetic photocatalysts in the remediation of emerging organic pollutants.

New Xanthene Dyes with NIR-II Emission Beyond 1200 nm for Efficient Tumor Angiography and Photothermal Therapy

Fluorescence (FL) bioimaging in the second near-infrared window (NIR-II, 1000-1700 nm) provides improved imaging quality and high resolution for diagnosis of deep-seated tumors. However, integrating FL bioimaging and photothermal therapy (PTT) in a single photoactive molecule exhibits a great challenge because a dramatic increase of PTT in the NIR-II window benefitting from the nonradiative decay will sacrifice the fluorescence brightness that is unfavorable for FL bioimaging. Therefore, balancing the radiative decay and nonradiative decay is an effective and rational design strategy. Herein, four NIR-II xanthene dyes (CL1-CL4) are synthesized with maximal emission beyond 1200 nm under 1064 nm excitation. CL4 exhibits the largest fluorescence quantum yield and a significant fluorescence enhancement after complexation with fetal bovine serum (FBS). As-prepared CL4/FBS has a maximal emission of 1235 nm and a high photothermal conversion efficiency of 36% under 1064 nm excitation. Bright and refined tumor vessels with a fine resolution of 0.23 mm can be clearly distinguished by CL4/FBS. In vivo studies show that a balanced utilization of fluorescence and photothermy in the NIR-II window is successfully achieved with superior biocompatibility. This efficient strategy provides promising avenue for precise theranostics of deep tumors.

Application of metalloporphyrin sensitizers for the treatment or diagnosis of tumors

At present, metalloporphyrin compounds demonstrate three main uses as anticancer sensitizers: (1) photosensitizers, (2) photothermal conversion agents, and (3) ultrasound sensitizers. Developing efficient sensitizers for cancer with excellent controllability and biocompatibility is an important goal of oncology medicine. Because of the different structural diversity of anticancer sensitizers, such sensitizers are used for treating cancers by employing a variety of tumor treatment methods such as mature photodynamic therapy, commonly used clinically photothermal therapy and promising sonodynamic therapy. Among the many sensitizers, metalloporphyrin-complex sensitizers attract wide attention due to their excellent performance in tumor treatment and diagnosis. This review briefly describes some metalloporphyrin anticancer drugs and diagnostic agents related to photodynamic, photothermal and sonodynamic therapy, and discusses the roles of metal atoms in these drugs.

Nanotechnology-based combinatorial phototherapy for enhanced cancer treatment

Nanotechnology-based phototherapy has attracted enormous attention to cancer treatment owning to its non-invasiveness, high controllability and accuracy. Given the fast development of anti-tumor strategies, we summarize various examples of multifunctional nanosystems to highlight the recent advances in nanotechnology-based combinatorial phototherapy towards improving cancer treatment. The limitations of the monotherapeutic approach and the superiority of the photo-involved combinatorial strategies are discussed in each part. The future breakthroughs and clinical perspectives of combinatorial phototherapy are also outlooked. Our perspectives may inspire researchers to develop more effective phototherapy-based cancer-treating approaches.

Cell membrane camouflaged biomimetic nanoparticles: Focusing on tumor theranostics

Nanoparticles (NPs) modified by cell membranes represent an emerging biomimetic platform that can mimic the innate biological functions resulting from the various cell membranes in biological systems. researchers focus on constructing the cell membrane camouflaged NPs using a wide variety of cells, such as red blood cell membranes (RBC), macrophages and cancer cells. Cell membrane camouflaged NPs (CMNPs) inherit the composition of cell membranes, including specific receptors, antigens, proteins, for target delivering to the tumor, escaping immune from clearance, and prolonging the blood circulation time, etc. Combining cell membrane-derived biological functions and the NP cores acted cargo carriers to encapsulate the imaging agents, CMNPs are widely developed to apply in tumor imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), fluorescence imaging (FL) and photoacoustic imaging (PA). Herein, in this review, we systematically summarize the superior functions of various CMNPs in tumor imaging, especially highlighting the advanced applications in different imaging techniques, which is to provide the theoretical supports for the development of precise guided imaging and tumor treatment.

A novel hypocrellin-based assembly for sonodynamic therapy against glioblastoma

The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM.

Amphiphilic Diketopyrrolopyrrole Derivatives for Efficient Near-Infrared Fluorescence Imaging and Photothermal Therapy

The design and synthesis of single-molecule amphiphilic and multifunctional phototherapeutic agents are important to cancer diagnosis and therapy. In this work, we developed three amphiphilic diketopyrrolopyrrole derivatives (TPADPP, DTPADPP, and TPADDPP) with different donor-acceptor structures and poly(ethylene glycol) side chains. The corresponding nanoparticles (NPs) were obtained via a self-assembly from three amphiphilic DPP derivatives and used as smart phototherapeutic agents for tumor diagnosis and treatment. The three amphiphilic DPP NPs exhibited near-infrared (NIR) emissions and good biocompatibility. Thus, they could be used as fluorescence (FL) imaging agents for guided therapy. DTPADPP NPs and TPADDPP NPs also displayed excellent photothermal performance and high accumulation in the tumor. Owing to these beneficial features, the DTPADPP NPs and TPADDPP NPs synthesized herein are suitable for NIR FL imaging and effective photothermal therapy against the tumor in vivo.

Biodegradable Hypocrellin B nanoparticles coated with neutrophil membranes for hepatocellular carcinoma photodynamics therapy effectively via JUNB/ROS signaling

Hepatocellular carcinoma (HCC) is an inflammation-induced and chemotherapy-resistant common liver cancer, and a major cause of death. Some natural products have been found to be used as photosensitizers in photodynamic therapy of HCC. Due to its specific molecular structure diversities and biological activities, current status of HCC treatment with nature production remains unsatisfactory, owing largely to the toxicity, side effect and inefficiency to drug targeting. Herein, we show a nanoparticle-based broad-spectrum anti-inflammatory strategy that naïve neutrophil membrane-coated PLGA nanoparticles (NM-HB NPs) were constructed for synchronous nearinfrared fluorescence (NIR FL) imaging and photodynamic therapy (PDT) for HCC. Moreover, NM-HB NPs inhibited the expression of JUNB and promoted the ROS production. JUNB depletion enhanced the anti-HCC effect of NM-HB NPs. Importantly, it was shown that NM-HB NPs are well targeted to the tumor site and overcomes the blood circulation and immune elimination in vivo and vitro. In a mouse model of HCC, the neutrophil membrane-coated nanoparticles (NM-HB NPs) show significant therapeutic efficacy by PDT and suppressing tumor tissue increase. All results demonstrated that NM coated HB NPs representing a viable and effective treatment option for HCC.

Dual-light triggered metabolizable nano-micelles for selective tumor-targeted photodynamic/hyperthermia therapy

Phototherapy, including photodynamic and photothermal therapies, is a non-invasive photo-triggered tumor treatment. Combination therapy and new synergistic therapeutic reagents may hold promise for improving these treatments. Herein, we report an amphiphilic iridium-based photosensitizer (C14-IP2000) loaded with a hydrophobic photo-thermal drug (ZnPc) to form nano-micelles (ZNPs) for dual-light triggered tumor phototherapy. The C14-IP2000 was contained within ZNPs consisting of an iridium complex core decorated with hydrophilic polyethylene glycol chains to extend the time in blood circulation, and two hydrophobic carbon chains to enhance the loading capacity and the hydrophobic interaction with the loaded reagent. The designed ZNPs showed effective blood circulation, passive tumor targeting ability, remarkable photodynamic conversion ability, and good photothermal conversion capability, and therefore may be used for combined tumor ablation. Our results demonstrated that the amphipathic bionic structure of ZNPs not only enables self-assembled reagent fabrication with prolonged circulation time and favorable metabolic characteristics for tumor combination therapy, but also provides a nanostructure strategy for the modification of functionalized reagents.

Albumin-based fluorescence resonance energy transfer nanoprobes for multileveled tumor tissue imaging and dye release imaging

Tumor tissue imaging and drug release imaging are both crucial for tumor imaging and image-guided drug delivery. It is urgent to develop a multileveled tumor imaging platform to realize the multiple imaging applications. In this work, we synthesized an albumin-based fluorescence resonance energy transfer (FRET) probe Cy5/7@HSA NPs containing two near-infrared cyanine dyes (CyBI5 and CyBI7) with high FRET efficiency (97 %). Excellent brightness and efficient FRET inside Cy5/7@HSA NPs enabled high-sensitive cell imaging and tumor imaging. This unique nanoprobe imaged 4T1 tumor-bearing mice with high sensitivity (TBR = 5.2) at 24 h post-injection and the dyes penetrated the tumor interior around 4 h post-injection. The release of dyes from nanoprobes was also tracked. This result shows the strong potential of this albumin-based FRET nanoprobe as multileveled tumor imaging platform for in vivo tumor imaging, drug delivery and image-guided surgery.

Serum protein-based nanoparticles for cancer diagnosis and treatment

Serum protein as naturally essential biomacromolecules has recently emerged as a versatile carrier for diagnostic and therapeutic drug delivery for cancer nanomedicine with superior biocompatibility, improved pharmacokinetics and enhanced targeting capacity. A variety of serum proteins have been utilized for drug delivery, mainly including albumin, ferritin/apoferritin, transferrin, low-density lipoprotein, high-density lipoprotein and hemoglobin. As evidenced by the success of paclitaxel-bound albumin nanoparticles (Abraxane^TM), serum protein-based nanoparticles have gained attractive attentions for precise biological design and potential clinical application. In this review, we summarize the general design strategies, targeting mechanisms and recent development of serum protein-based nanoparticles in the field of cancer nanomedicine. Moreover, we also concisely specify the current challenges to be addressed for a bright future of serum protein-based nanomedicines.

Near-Infrared Hypocrellin Derivatives for Synergistic Photodynamic and Photothermal Therapy

Hypocrellin B (HB) derived from naturally produced hypocrellins has attracted considerable attention in photodynamic therapy (PDT) because of its excellent photosensitive properties. However, the weak absorption within a "phototherapy window" (600-900 nm) and poor water solubility of HB have limited its clinical application. In this study, two HB derivatives (i. e., HE and HF) were designed and synthesized for the first time by introducing two different substituent groups into the HB structure. The obtained derivatives showed a broad absorption band covering the near-infrared (NIR) region, NIR emission (peaked at 805 nm), and singlet oxygen quantum yields of 0.27/0.31. HE-PEG-NPs were also prepared using 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-mPEG2000) to achieve excellent dispersion in water and further explored their practical applications. HE-PEG-NPs not only retained their ¹ O₂ -generating ability, but also exhibited a photothermal conversion efficiency of 25.9%. In vitro and in vivo therapeutic results revealed that the synergetic effect of HE-PEG-NPs on PDT and photothermal therapy (PTT) could achieve a good performance. Therefore, HE-PEG-NPs could be regarded as a promising phototheranostic agent.

Highly swelling pH-responsive microgels for dual mode near infra-red fluorescence reporting and imaging

Near infra-red (NIR) fluorescence is a desirable property for probe particles because such deeply penetrating light enables remote reporting of the local environment in complex surroundings and imaging. Here, two NIR non-radiative energy transfer (NRET) fluorophores (Cy5 and Cy5.5) are coupled to preformed pH-responsive poly(ethylacrylate-methacrylic acid-divinylbenzene) microgel particles (PEA-MAA-5/5.5 MGs) to obtain new NIR fluorescent probes that are cytocompatible and swell strongly. NIR ratiometric photoluminescence (PL) intensity analysis enables reporting of pH-triggered PEA-MAA-5/5.5 MG particle swelling ratios over a very wide range (from 1-90). The dispersions have greatly improved colloidal stability compared to a reference temperature-responsive NIR MG based on poly(N-isopropylacrylamide) (PNP-5/5.5). We also show that the wavelength of maximum PL intensity (λ _max) is a second PL parameter that enables remote reporting of swelling for both PEA-MAA-5/5.5 and PNP-5/5.5 MGs. After internalization the PEA-MAA-5/5.5 MGs are successfully imaged in stem cells using NIR light. They are also imaged after subcutaneous injection into model tissue using NIR light. The new NIR PEA-MAA-5/5.5 MGs have excellent potential for reporting their swelling states (and any changes) within physiological settings as well as very high ionic strength environments (e.g., waste water).

Hypocrellin-Based Multifunctional Phototheranostic Agent for NIR-Triggered Targeted Chemo/Photodynamic/Photothermal Synergistic Therapy against Glioblastoma

A huge challenge exists in the diagnosis and treatment of malignant glioblastoma (GBM) due to the presence of the blood-brain barrier (BBB). Herein, a multifunctional phototheranostic agent is designed on the basis of an octadecane-modified temozolomide (TMZ-C18) for chemotherapy, a dicysteamine-modified hypocrellin derivative (DCHB) as a natural-origin photosensitizer with a singlet oxygen (¹O₂) quantum yield of 0.51, and a cyclic peptide (cRGD) as a targeting unit against glioblastoma. Co-encapsulated DCHB and TMZ-C18 assembly with cRGD decoration, referred to as DTRGD NPs, shows a wide absorption at the NIR region peaked at 703 nm, an NIR emission peak at 720 nm, good photostability, high photothermal conversion efficiency (33%), and effective degradation of TMZ-C18. More importantly, DTRGD NPs can efficiently break through the blood-brain barrier and enrich in the orthotopic glioblastoma. The treatment of subcutaneous U87MG tumor beard mice demonstrates that DTRGD NPs present remarkable anticancer efficiency and the targeted chemo/photodynamic/photothermal synergistic therapy can be achieved with almost no toxicity. This multifunctional phototheranostic agent shows great potential for the diagnosis and treatment of glioblastoma.