RBC Membrane Camouflaged Semiconducting Polymer Nanoparticles for Near-Infrared Photoacoustic Imaging and Photothermal Therapy

Biomimetic Ghost Nanomedicine-Based Optotheranostics for Cancer

Theranostic medicine combines diagnostics and therapeutics, focusing on solid tumors at minimal doses. Optically activated photosensitizers are significant examples owing to their photophysical and chemical properties. Several optotheranostics have been tested that convert light to imaging signals, therapeutic radicals, and heat. Upon light exposure, conjugated photosensitizers kill tumor cells by producing reactive oxygen species and heat or by releasing cancer antigens. Despite clinical trials, these molecularly conjugated photosensitizers require protection from their surroundings and a localized direction for site-specific delivery during blood circulation. Therefore, cell membrane biomimetic ghosts have been proposed for precise and safe delivery of these optically active large molecules, which are clinically relevant because of their biocompatibility, long circulation time, bypass of immune cell recognition, and targeting ability. This review focuses on the role of biomimetic nanoparticles in the treatment and diagnosis of tumors through light-mediated diagnostics and therapy, providing insights into their preclinical and clinical status.

Biomimetic MicroRNAs-Selenium-Nanocomposites for Targeted and Combined Hyperlipidemia Therapy

Hyperlipidemia is considered as a high-risk factor for leading to coronary heart disease. MicroRNA-148a-3p (miR-148a-3p) inhibitor is a potential therapeutic target to bind low-density lipoprotein cholesterol receptors (LDLR) for decreasing the levels of low-density lipoprotein cholesterol in plasma. However, the therapeutic effects are not ideal in the clinical translation of nucleic acids treatment, owing to the short circulation time in vivo. Therefore, a platelet membrane (PM) cloaks Se nanoparticles (SeNPs) delivery system with chitosan (CS) modifies and miR-148a-3p inhibitors encapsulated is designed (PM/CS-SeNPs/miR). The PM/CS-SeNPs/miR shows a uniform shell-core structure with a particle size of ≈90 nm. Co-delivering miR-148a-3p inhibitors and Se effectively alleviate hyperlipidemia via LDLR pathway and Toll-Like Receptor 4 (TLR-4)/NF-κB signaling pathway, respectively. Furthermore, coated by PM, PM/CS-SeNPs/miR successfully prolong circulation time to 48 h in vivo and quickly target to liver with no toxicity. This dual combination therapy with miRNAs and Se based on nanoparticles targeted delivery presents a high-performance strategy for precise hyperlipidemia treatment.

Bufotalin-loaded biomimetic Prussian blue nanoparticles for colorectal cancer chemo-photothermal ferroptosis therapy

Purpose: We constructed biomimetic nanoparticles with biocompatible, tumor-targeting, laser-responsive properties for ferroptosis-induced colorectal cancer chemo-photothermal therapy, with the aim to realize double-hit ferroptosis treatment for colorectal cancer. Methods: The nanoparticles were prepared by first loading the chemotherapy drug bufotalin (CS-5) with Prussian blue (PB), then combining a hybridized erythrocyte-tumor membrane (M) with PB@CS-5 to produce PB@CS-5@M. The chemo-photothermal therapy efficiency of PB@CS-5@M was tested by in vitro and in vivo experiments. Results and conclusion: The combined PB and CS-5 act as promising ferroptosis inducers to enhance ferroptosis efficacy. The hyperthermia induced by laser stimulation can trigger PB to release CS-5 and iron and ferrous ions, which further promotes ferroptosis.

Recent advances of polymeric nanoplatforms for cancer treatment: smart delivery systems (SDS), nanotheranostics and multidrug resistance (MDR) inhibition

Nanotheranostics is a promising field that combines the benefits of diagnostic and treatment into a single nano-platform that not only administers treatment but also allows for real-time monitoring of therapeutic response, decreasing the possibility of under/over-drug dosing. Furthermore, developing smart delivery systems (SDSs) for cancer theranostics that can take advantage of various tumour microenvironment (TME) conditions (such as deformed tumour vasculature, various over-expressed receptor proteins, reduced pH, oxidative stress, and resulting elevated glutathione levels) can aid in achieving improved pharmacokinetics, higher tumour accumulation, enhanced antitumour efficacy, and/or decreased side effects and multidrug resistance (MDR) inhibition. Polymeric nanoparticles (PNPs) are being widely investigated in this regard due to their unique features such as small size, passive/active targeting possibility, better pharmaceutical kinetics and biological distribution, decreased adverse reactions of the established drugs, inherent inhibitory properties to MDR efflux pump proteins, as well as the feasibility of delivering numerous therapeutic substances in just one design. Hence in this review, we have primarily discussed PNPs based targeted and/or controlled SDSs in which we have elaborated upon different TME mediated nanotheranostic platforms (NTPs) including active/passive/magnetic targeting platforms along with pH/ROS/redox-responsive platforms. Besides, we have elucidated different imaging guided cancer therapeutic platforms based on four major cancer imaging techniques i.e., fluorescence/photo-acoustic/radionuclide/magnetic resonance imaging, Furthermore, we have deliberated some of the most recently developed PNPs based multimodal NTPs (by combining two or more imaging or therapy techniques on a single nanoplatform) in cancer theranostics. Moreover, we have provided a brief update on PNPs based NTP which are recently developed to overcome MDR for effective cancer treatment. Additionally, we have briefly discussed about the tissue biodistribution/tumour targeting efficiency of these nanoplatforms along with recent preclinical/clinical studies. Finally, we have elaborated on various limitations associated with PNPs based nanoplatforms.

A Stable Open-Shell Conjugated Diradical Polymer with Ultra-High Photothermal Conversion Efficiency for NIR-II Photo-Immunotherapy of Metastatic Tumor

Massive efforts have been concentrated on the advance of eminent near-infrared (NIR) photothermal materials (PTMs) in the NIR-II window (1000-1700 nm), especially organic PTMs because of their intrinsic biological safety compared with inorganic PTMs. However, so far, only a few NIR-II-responsive organic PTMs was explored, and their photothermal conversion efficiencies (PCEs) still remain relatively low. Herein, donor-acceptor conjugated diradical polymers with open-shell characteristics are explored for synergistically photothermal immunotherapy of metastatic tumors in the NIR-II window. By employing side-chain regulation, the conjugated diradical polymer TTB-2 with obvious NIR-II absorption was developed, and its nanoparticles realize a record-breaking PCE of 87.7% upon NIR-II light illustration. In vitro and in vivo experiments demonstrate that TTB-2 nanoparticles show good tumor photoablation with navigation of photoacoustic imaging in the NIR-II window, without any side-effect. Moreover, by combining with PD-1 antibody, the pulmonary metastasis of breast cancer is high-effectively prevented by the efficient photo-immunity effect. Thus, this study explores superior PTMs for cancer metastasis theranostics in the NIR-II window, offering a new horizon in developing radical-characteristic NIR-II photothermal materials.

Combination cancer imaging and phototherapy mediated by membrane-wrapped nanoparticles

Cancer is a devastating health problem with inadequate treatment options. Many conventional treatments for solid-tumor cancers lack tumor specificity, which results in low efficacy and off-target damage to healthy tissues. Nanoparticle (NP)-mediated photothermal therapy (PTT) is a promising minimally invasive treatment for solid-tumor cancers that has entered clinical trials. Traditionally, NPs used for PTT are coated with passivating agents and/or targeting ligands, but alternative coatings are being explored to enhance tumor specific delivery. In particular, cell-derived membranes have emerged as promising coatings that improve the biointerfacing of photoactive NPs, which reduces their immune recognition, prolongs their systemic circulation and increases their tumor accumulation, allowing for more effective PTT. To maximize treatment success, membrane-wrapped nanoparticles (MWNPs) that enable dual tumor imaging and PTT are being explored. These multifunctional theranostic NPs can be used to enhance tumor detection and/or ensure a sufficient quantity of NPs that have arrived in the tumor prior to laser irradiation. This review summarizes the current state-of-the-art in engineering MWNPs for combination cancer imaging and PTT and discusses considerations for the path toward clinical translation.

Photothermal Therapy Mediated Hybrid Membrane Derived Nano-formulation for Enhanced Cancer Therapy

Emodin is applied as an antitumor drug in many tumor therapies. However, its pharmacology performances are limited due to its low solubility. Herein, we fused erythrocyte and macrophage to form a hybrid membrane (EMHM) and encapsulated emodin to form hybrid membrane-coated nanoparticles. We employed glycyrrhizin to increase the solubility of emodin first and prepared the hybrid membrane nanoparticle-coated emodin and glycyrrhizin (EG@EMHM NPs) which exhibited an average particle size of 170 ± 20 nm and encapsulation efficiency of 98.13 ± 0.67%. The half-inhibitory concentrations (IC50) of EG@EMHM NPs were 1.166 μg/mL, which is half of the free emodin. Based on the photosensitivity of emodin, the reactive oxygen species (ROS) results disclosed that ROS levels of the photodynamic therapy (PDT) section were higher than the normal section (P < 0.05). Compared to the normal section, PDT-mediated EG@EMHM NPs could induce an early stage of apoptosis of B16. The western blot and flow cytometry results verified that PDT-mediated EG@EMHM NPs can significantly improve the solubility of emodin and perform a remarkably antitumor effect on melanoma via BAX and BCL-2 pathway. The application of the combined chemical and PDT therapy could provide an improving target therapy for cutaneous melanoma and also may offer an idea for other insoluble components sources of traditional Chinese medicine. Schematic of EG@EMHM NPs formulation.

Near-infrared absorbing semiconducting polymer nanomedicines for cancer therapy

As a new type of organic optical nanomaterials, semiconducting polymer nanoparticles (SPNs) have the advantages of good optical characteristics and photostability, low toxicity concerns, and relatively simple preparation processes. Particularly, near-infrared (NIR) absorbing SPNs have shown a great promise in biomedicine. In addition to acting as nanoprobes for molecular imaging, these SPNs can produce local heat and reactive oxygen species with the stimulation of NIR light, allowing photothermal therapy (PTT) and photodynamic therapy (PDT), respectively. Herein, we summarize the recent development of SPN-based nanomedicines for cancer therapy. The rational designs of SPNs for enhanced PTT, PDT, or combinational PTT/PDT to achieve effective ablation of tumor tissues are highlighted. Via loading/conjugating SPNs with other therapeutic elements (such as chemotherapeutic drugs and immunotherapeutic agents), phototherapy-combined chemotherapy or immunotherapy can be realized, which is then discussed. In especial, the constructions of SPN-based nanomedicines for NIR photoactivatable chemotherapy and immunotherapy are introduced with representative examples. Finally, we discuss the current challenges and key concerns of SPNs for their biomedical applications and give an outlook for their future clinical translation. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Regulating the microenvironment with nanomaterials: Potential strategies to ameliorate COVID-19

COVID-19, caused by SARS-CoV-2, has resulted in serious economic and health burdens. Current treatments remain inadequate to extinguish the epidemic, and efficient therapeutic approaches for COVID-19 are urgently being sought. Interestingly, accumulating evidence suggests that microenvironmental disorder plays an important role in the progression of COVID-19 in patients. In addition, recent advances in nanomaterial technologies provide promising opportunities for alleviating the altered homeostasis induced by a viral infection, providing new insight into COVID-19 treatment. Most literature reviews focus only on certain aspects of microenvironment alterations and fail to provide a comprehensive overview of the changes in homeostasis in COVID-19 patients. To fill this gap, this review systematically discusses alterations of homeostasis in COVID-19 patients and potential mechanisms. Next, advances in nanotechnology-based strategies for promoting homeostasis restoration are summarized. Finally, we discuss the challenges and prospects of using nanomaterials for COVID-19 management. This review provides a new strategy and insights into treating COVID-19 and other diseases associated with microenvironment disorders.

Nanotechnology-based cell-mediated delivery systems for cancer therapy and diagnosis

The global prevalence of cancer is increasing, necessitating new additions to traditional treatments and diagnoses to address shortcomings such as ineffectiveness, complications, and high cost. In this context, nano and microparticulate carriers stand out due to their unique properties such as controlled release, higher bioavailability, and lower toxicity. Despite their popularity, they face several challenges including rapid liver uptake, low chemical stability in blood circulation, immunogenicity concerns, and acute adverse effects. Cell-mediated delivery systems are important topics to research because of their biocompatibility, biodegradability, prolonged delivery, high loading capacity, and targeted drug delivery capabilities. To date, a variety of cells including blood, immune, cancer, and stem cells, sperm, and bacteria have been combined with nanoparticles to develop efficient targeted cancer delivery or diagnosis systems. The review paper aimed to provide an overview of the potential applications of cell-based delivery systems in cancer therapy and diagnosis.

Cell surface-nanoengineering for cancer targeting immunoregulation and precise immunotherapy

Living cells have become ideal therapeutic agents for cancer treatment owing to their innate activities, such as efficient tumor targeting and delivery, easy engineering, immunomodulatory properties, and fewer adverse effects. However, cell agents are often fragile to rigorous tumor microenvironment (TME) and limited by inadequate therapeutic responses, leading to unwanted treatment efficacy. Cell nanomodification, particularly the cell surface-nanoengineering has emerged as reliable and efficient strategy that not only combines cell activity properties with nanomaterials but also endows them with extra novel functions, enabling to achieve remarkable treatment results. In this review, we systematically introduce two major strategies have been adopted to develop cell surface engineering with nanomaterials, mainly including living cell nano-backpacks and cell membrane-mimicking nanoparticles (NPs). Based on various functional NPs and cell types, we focus on reviewing the cell-surface nanoengineering for targeted drug delivery, immune microenvironment regulation, and precisely antitumor therapy. The advances and challenges of cell surface-nanoengineered antitumor agents for cancer therapy applications are further discussed in future clinical practice. This review provides an overview of the advances in cell surface-engineering for targeting immunoregulation and treatment and could contribute to the future of advanced cell-based antitumor therapeutic applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Cells at the Nanoscale.

Development of novel polymeric nanoagents and their potential in cancer diagnosis and therapy runing title: Polymeric nanoagents for cancer theranostics

Cancer has been one of the leading factors of death around the world. Cancer patients usually have low 5-year survival rates and poor life quality requiring substantial improvement. In clinic, the presenting diagnostic strategies lack sensitivity with only a small proportion of patients can be accurately identified. For diagnosed patients, most of them are at the advanced stages thus being delayed to receive treatment. Therefore, it is eager to investigate and develop highly effective and accurate techniques for cancer early diagnosis and individualized therapy. Various nanoplatforms are emerging as imaging agents and drug carriers for cancer theranostics recently. Novel polymeric nanoagents, as a potent exemplar, have extraordinary merits, such as good stability, high biosafety and high drug loading efficacy, showing the great prospect for cancer early diagnosis and precise treatment. Herein, we review the recent advances in novel polymeric nanoagents and elucidate their synthesis procedures. We further introduce the applications of novel polymeric nanoagents in cancer diagnosis, treatment, and theranostics, as well as associated challenges and prospects in this field.

Red blood cell membrane nanoparticles for tumor phototherapy

Non-invasive phototherapy includes photodynamic therapy (PDT) and photothermal therapy (PTT), and has garnered special interest in anti-tumor therapy. However, traditional photosensitizers or photothermal agents are faced with major challenges, including easy recognition by immune system, rapid clearance from blood circulation, and low accumulation in target sites. Combining the characteristics of natural cell membrane with the characteristics of photosensitizer or photothermal agent is an important technology to achieve the ideal therapeutic effect of cancer. Red cell membrane (RBMs) coated can disguise phototherapy agents as endogenous substances, thus constructing a new nano bionic therapeutic platform, resisting blood clearance and prolonging circulation time. At present, a variety of phototherapy agents based on Nano-RBMs have been isolated or designed. In this review, firstly, the basic principles of Nano-RBMs and phototherapy are expounded respectively. Then, the latest progress of Nano-RBMs for PDT, PTT and PDT/PTT applications in recent five years has been introduced respectively. Finally, the problems and challenges of Nano-RBMs in the field of phototherapy are put forward.

Targeted Delivery of PD-L1-Derived Phosphorylation-Mimicking Peptides by Engineered Biomimetic Nanovesicles to Enhance Osteosarcoma Treatment

Osteosarcoma is a rare malignant bone-originating tumor that usually occurs in young people. Programmed cell death 1 ligand 1 (PD-L1), an immune checkpoint protein, is highly expressed in osteosarcoma tissues. Several recent studies have indicated that the tumor-related role of PD-L1 in tumors, especially non-plasma membrane (NPM)-localized PD-L1, is not limited to immune regulation in osteosarcoma. Here, mass spectrometry analysis is combined with RNA-seq examination to identify the intracellular binding partners of PD-L1 and elucidate the underlying mechanism of its action. It is found that the NPM-localized PD-L1 interacted with Insulin-like growth factor binding protein-3 (IGFBP3) to promote osteosarcoma tumor growth by activating mTOR signaling. This interaction is enforced after phosphoglyceratekinase1 (PGK1)-mediated PD-L1 phosphorylation. Based on these findings, a phosphorylation-mimicking peptide is designed from PD-L1 and it is encapsulated with a Cyclic RGD (cRGD)-modified red blood cell membrane (RBCM) vesicle (Peptide@cRGD-M). The Peptide@cRGD-M precisely delivers the PD-L1-derived phosphorylation-mimicking peptide into osteosarcoma lesions and significantly promotes its therapeutic effect on the tumor. Therefore, this investigation not only highlights the function of NPM-localized PD-L1, but also uses an engineering approach to synthesize a small molecular peptide capable of inhibiting osteosarcoma growth.

Soft nano and microstructures for the photomodulation of cellular signaling and behavior

Photoresponsive soft materials are everywhere in the nature, from human's retina tissues to plants, and have been the inspiration for engineers in the development of modern biomedical materials. Light as an external stimulus is particularly attractive because it is relatively cheap, noninvasive to superficial biological tissues, can be delivered contactless and offers high spatiotemporal control. In the biomedical field, soft materials that respond to long wavelength or that incorporate a photon upconversion mechanism are desired to overcome the limited UV-visible light penetration into biological tissues. Upon light exposure, photosensitive soft materials respond through mechanisms of isomerization, crosslinking or cleavage, hyperthermia, photoreactions, electrical current generation, among others. In this review, we discuss the most recent applications of photosensitive soft materials in the modulation of cellular behavior, for tissue engineering and regenerative medicine, in drug delivery and for phototherapies.

Photoacoustic Imaging Probes for Theranostic Applications

Photoacoustic imaging (PAI), an emerging biomedical imaging technology, capitalizes on a wide range of endogenous chromophores and exogenous contrast agents to offer detailed information related to the functional and molecular content of diseased biological tissues. Compared with traditional imaging technologies, PAI offers outstanding advantages, such as a higher spatial resolution, deeper penetrability in biological tissues, and improved imaging contrast. Based on nanomaterials and small molecular organic dyes, a huge number of contrast agents have recently been developed as PAI probes for disease diagnosis and treatment. Herein, we report the recent advances in the development of nanomaterials and organic dye-based PAI probes. The current challenges in the field and future research directions for the designing and fabrication of PAI probes are proposed.

Design principles of bioinspired interfaces for biomedical applications in therapeutics and imaging

In the past two decades, we have witnessed rapid developments in nanotechnology, especially in biomedical applications such as drug delivery, biosensing, and bioimaging. The most commonly used nanomaterials in biomedical applications are nanoparticles, which serve as carriers for various therapeutic and contrast reagents. Since nanomaterials are in direct contact with biological samples, biocompatibility is one of the most important issues for the fabrication and synthesis of nanomaterials for biomedical applications. To achieve specific recognition of biomolecules for targeted delivery and biomolecular sensing, it is common practice to engineer the surfaces of nanomaterials with recognition moieties. This mini-review summarizes different approaches for engineering the interfaces of nanomaterials to improve their biocompatibility and specific recognition properties. We also focus on design strategies that mimic biological systems such as cell membranes of red blood cells, leukocytes, platelets, cancer cells, and bacteria.

Hybrid Membrane-Derived Nanoparticles for Isoliquiritin Enhanced Glioma Therapy

Due to the obstruction and heterogeneity of the blood-brain barrier, the clinical treatment of glioma has been extremely difficult. Isoliquiritigenin (ISL) exhibits antitumor effects, but its low solubility and bioavailability limit its application potential. Herein, we established a nanoscale hybrid membrane-derived system composed of erythrocytes and tumor cells. By encapsulating ISL in hybrid membrane nanoparticles, ISL is expected to be enhanced for the targeting and long-circulation in gliomas therapy. We fused erythrocytes with human glioma cells U251 and extracted the fusion membrane via hypotension, termed as hybrid membrane (HM). HM-camouflaged ISL nanoparticles (ISL@HM NPs) were prepared and featured with FT-IR, SEM, TEM, and DLS particle analysis. As the results concluded, the ISL active pharmaceutical ingredients (APIs) were successfully encapsulated with HM membranes, and the NPs loading efficiency was 38.9 ± 2.99% under maximum entrapment efficiency. By comparing the IC50 of free ISL and NPs, we verified that the solubility and antitumor effect of NPs was markedly enhanced. We also investigated the mechanism of the antitumor effect of ISL@HM NPs, which revealed a marked inhibition of tumor cell proliferation and promotion of senescence and apoptosis of tumor cells of the formulation. In addition, the FSC and WB results examined the effects of different concentrations of ISL@HM NPs on tumor cell disruption and apoptotic protein expression. Finally, it can be concluded that hybridized membrane-derived nanoparticles could prominently increase the solubility of insoluble materials (as ISL), and also enhance its targeting and antitumor effect.

Membrane-wrapped nanoparticles for photothermal cancer therapy

Cancer is a global health problem that needs effective treatment strategies. Conventional treatments for solid-tumor cancers are unsatisfactory because they cause unintended harm to healthy tissues and are susceptible to cancer cell resistance. Nanoparticle-mediated photothermal therapy is a minimally invasive treatment for solid-tumor cancers that has immense promise as a standalone therapy or adjuvant to other treatments like chemotherapy, immunotherapy, or radiotherapy. To maximize the success of photothermal therapy, light-responsive nanoparticles can be camouflaged with cell membranes to endow them with unique biointerfacing capabilities that reduce opsonization, prolong systemic circulation, and improve tumor delivery through enhanced passive accumulation or homotypic targeting. This ensures a sufficient dose of photoresponsive nanoparticles arrives at tumor sites to enable their complete thermal ablation. This review summarizes the state-of-the-art in cell membrane camouflaged nanoparticles for photothermal cancer therapy and provides insights to the path forward for clinical translation.

Nanobots-based advancement in targeted drug delivery and imaging: An update

Manipulation and targeted navigation of nanobots in complex biological conditions can be achieved by chemical reactions, by applying external forces, and via motile cells. Several studies have applied fuel-based and fuel-free propulsion mechanisms for nanobots movements in environmental sciences and robotics. However, their applications in biomedical sciences are still in the budding phase. Therefore, the current review introduces the fundamentals of different propulsion strategies based on the advantageous features of applied nanomaterials or cellular components. Furthermore, the recent developments reported in various literatures on next-generation nanobots, such as Xenobots with applications of in-vitro and in-vivo drug delivery and imaging were also explored in detail. The challenges and the future prospects are also highlighted with corresponding advantages and limitations of nanobots in biomedical applications. This review concludes that with ever booming research enthusiasm in this field and increasing multidisciplinary cooperation, micro-/nanorobots with intelligence and multifunctions will emerge in the near future, which would have a profound impact on the treatment of diseases.

Looking deep inside tissue with photoacoustic molecular probes: a review

Significance

Deep tissue noninvasive high-resolution imaging with light is challenging due to the high degree of light absorption and scattering in biological tissue. Photoacoustic imaging (PAI) can overcome some of the challenges of pure optical or ultrasound imaging to provide high-resolution deep tissue imaging. However, label-free PAI signals from light absorbing chromophores within the tissue are nonspecific. The use of exogeneous contrast agents (probes) not only enhances the imaging contrast (and imaging depth) but also increases the specificity of PAI by binding only to targeted molecules and often providing signals distinct from the background.

Aim

We aim to review the current development and future progression of photoacoustic molecular probes/contrast agents.

Approach

First, PAI and the need for using contrast agents are briefly introduced. Then, the recent development of contrast agents in terms of materials used to construct them is discussed. Then, various probes are discussed based on targeting mechanisms, in vivo molecular imaging applications, multimodal uses, and use in theranostic applications.

Results

Material combinations are being used to develop highly specific contrast agents. In addition to passive accumulation, probes utilizing activation mechanisms show promise for greater controllability. Several probes also enable concurrent multimodal use with fluorescence, ultrasound, Raman, magnetic resonance imaging, and computed tomography. Finally, targeted probes are also shown to aid localized and molecularly specific photo-induced therapy.

Conclusions

The development of contrast agents provides a promising prospect for increased contrast, higher imaging depth, and molecularly specific information. Of note are agents that allow for controlled activation, explore other optical windows, and enable multimodal use to overcome some of the shortcomings of label-free PAI.

Gold-seaurchin based immunomodulator enabling photothermal intervention and αCD16 transfection to boost NK cell adoptive immunotherapy

Despite huge potentials of NK cells in adoptive cell therapy (ACT), formidable physical barriers of the tumor tissue and deficiency of recognizing signals on tumor cells severely prevent NK cell infiltrating, activating and killing performances. Herein, a nano-immunomodulator AuNSP@αCD16 (CD16 antibody encoding plasmid) is explored to remodel the tumor microenvironment (TME) for improving the antitumor effects of adoptive NK cells. The as-prepared AuNSP, with a seaurchin-like gold core and a cationic polymer shell, exhibited a high gene transfection efficiency and a stable NIR-II photothermal capacity. The AuNSP could trigger mild photothermal intervention to partly destroy tumors and collapse the dense physical barriers, making a permeable TME for NK cell infiltration. What's more, the AuNSP could achieve αCD16 gene transfection to modify tumor surface with CD16 antibody, marking a unique structure on tumor cells for NK cell recognition and then lead to strong NK cell activation by CD16-mediated antibody-dependent cellular cytotoxicity (ADCC). As expected, the designed AuNSP@αCD16 induced an immune-favorable TME for NK cell performing killing functions against solid tumors, increasing the release of cytolytic granules and proinflammatory cytokines, which ultimately achieved a robustly boosted NK cell-based immunotherapy. Hence, the AuNSP@αCD16-mediated TME reconstituting strategy provides a substantial perspective for NK-based ACT on solid tumors. STATEMENT OF SIGNIFICANCE: In adoptive cell therapy (ACT), natural killer (NK) cells exhibit greater off-the-shelf utility and improved safety comparing with T cells, but the efficacy of NK cell therapy is severely compromised by formidable physical barriers of the tumor tissue and deficiency of NK cell recognizing signals on tumor cells. Herein, a nano-immunomodulator AuNSP@αCD16, with the abilities of inducing mild photothermal intervention and modifying the tumor cell surface with αCD16, is explored to reconstruct an infiltration-favorable and activation-facilitating tumor microenvironment for NK cells to perform killing functions. Such a simple and safe strategy is believed as a very promising candidate for future NK-based ACT.

Long circulation and tumor-targeting biomimetic nanoparticles for efficient chemo/photothermal synergistic therapy

Photothermal therapy combined with chemotherapy based on nanomedicine has been considered a promising strategy for improving therapeutic efficacy in a tumor. However, nanomedicine can be easily cleared by the immune system without specific surface engineering modifications, thus affecting the ultimate efficacy. Herein, multifunctional biomimetic nanoparticles (Bio-RBCm@PDA@MSN-DOX) with enhanced long circulation and targeting ability are constructed by coating large pore-sized mesoporous silica (MSN) with polydopamine (PDA) layers in a biotin modified red blood cell membrane (Bio-RBCm) for efficient chemo/photothermal synergistic therapy. It is demonstrated that Bio-RBCm@PDA@MSN-DOX presents high photothermal conversion efficiency (40.17%) and enhanced capability to accelerate the release of the anticancer drug (doxorubicin, DOX), thus showing a good synergistic therapeutic effect in cell experiments. More importantly, with the assistance of the biotin and RBC membrane, Bio-RBCm@PDA@MSN-DOX can successfully evade immune clearance and effectively target transport to HeLa tumor sites, finally accomplishing up to 98.95% tumor inhibition with negligible side effects to normal tissues. This multilayer structure presents a valuable model for future therapeutic applications with safe and effective tumor chemotherapy and photothermal therapy.

Nanoplatform Self-Assembly from Small Molecules of Porphyrin Derivatives for NIR-II Fluorescence Imaging Guided Photothermal-Immunotherapy

Combinatorial photothermal and immunotherapy have demonstrated great potential to remove primary tumors, suppress metastases, and prevent tumor recurrence. However, this strategy still confronts patients with many limitations, such as complex components, sophisticated construction, and inadequate therapeutic efficacy. In this work, small molecules of porphyrin derivatives (PPor) which can self-assemble into monodispersed nanoparticles without supplement of any other ingredients or surfactants are developed. The formed PPor nanoparticles (PPor NPs) exhibit highly photothermal conversion efficiency of 70% and NIR-II luminous abilities originate from the strong intramolecular charge transfer (ICT) effect of D-A structure under 808 nm laser irradiation, thus achieving NIR-II fluorescence imaging guided photothermal therapy (PTT) against primary tumors with a high cure rate. More importantly, tumor-associated antigens (TAAs), together with damage-associated molecular patterns (DAMPs) released from PTT-treated cancer cells, are proved to elicit immune responses to some degree. After combination with programmed cell death-1 (PD-1) antibodies, a robust systematic antitumor immunity is generated to restrain both primary and abscopal tumors growth, prolong survival, and prevent pulmonary metastasis on an aggressive 4T1 murine breast tumor model. Thus, this study provides a promising therapeutic paradigm with porphyrin derivatives nano-assembly as phototheranostic agents for the treatment of aggressive tumors with high efficiency.

Nanomaterials in cancer: Reviewing the combination of hyperthermia and triggered chemotherapy

Nanoparticle mediated hyperthermia has been explored as a method to increase cancer treatment efficacy by heating tumours inside-out. With that purpose, nanoparticles have been designed and their properties tailored to respond to external stimuli and convert the supplied energy into heat, therefore inducing damage to tumour cells. Moreover, the combination of hyperthermia with chemotherapy has been described as a more effective strategy due to the synergy between the high temperature and the drug's effects, also associated with a remote controlled and on-demand drug release. In this review, the methods behind nanoparticle mediated hyperthermia, namely material design, external stimuli response and energy conversion will be discussed and critically analysed. We will address the most relevant studies on hyperthermia and temperature triggered drug release for cancer treatment. Finally, the advantages, difficulties and challenges of this therapeutic strategy will be discussed, while giving insight for future developments.

Remodeling Tumor-Associated Neutrophils to Enhance Dendritic Cell-Based HCC Neoantigen Nano-Vaccine Efficiency

Hepatocellular carcinoma (HCC) commonly emerges in an immunologically "cold" state, thereafter protects it away from cytolytic attack by tumor-infiltrating lymphocytes, resulting in poor response to immunotherapy. Herein, an acidic/photo-sensitive dendritic cell (DCs)-based neoantigen nano-vaccine has been explored to convert tumor immune "cold" state into "hot", and remodel tumor-associated neutrophils to potentiate anticancer immune response for enhancing immunotherapy efficiency. The nano-vaccine is constructed by SiPCCl₂ -hybridized mesoporous silica with coordination of Fe(III)-captopril, and coating with exfoliated membrane of matured DCs by H22-specific neoantigen stimulation. The nano-vaccines actively target H22 tumors and induce immunological cell death to boost tumor-associated antigen release by the generation of excess ¹ O₂ through photodynamic therapy, which act as in situ tumor vaccination to strengthen antitumor T-cell response against primary H22 tumor growth. Interestingly, the nano-vaccines are also home to lymph nodes to directly induce the activation and proliferation of neoantigen-specific T cells to suppress the primary/distal tumor growth. Moreover, the acidic-triggered captopril release in tumor microenvironment can polarize the protumoral N2 phenotype neutrophils to antitumor N1 phenotype for improving the immune effects to achieve complete tumor regression (83%) in H22-bearing mice and prolong the survival time. This work provides an alternative approach for developing novel HCC immunotherapy strategies.

Cell Membrane-Cloaked Nanotherapeutics for Targeted Drug Delivery

Cell membrane cloaking technique is bioinspired nanotechnology that takes advantage of naturally derived design cues for surface modification of nanoparticles. Unlike modification with synthetic materials, cell membranes can replicate complex physicochemical properties and biomimetic functions of the parent cell source. This technique indeed has the potential to greatly augment existing nanotherapeutic platforms. Here, we provide a comprehensive overview of engineered cell membrane-based nanotherapeutics for targeted drug delivery and biomedical applications and discuss the challenges and opportunities of cell membrane cloaking techniques for clinical translation.

Red Blood Cell-Mimic Nanocatalyst Triggering Radical Storm to Augment Cancer Immunotherapy

Red blood cells (RBCs) have recently emerged as promosing candidates for cancer treatment in terms of relieving tumor hypoxia and inducing oxidative damage against cancer cells, but they are still far from satisfactory due to their limited oxygen transport and reactive oxygen species generation rate in tumor tissue. Herein, artificial RBCs (designated FTP@RBCM) with radical storm production ability were developed for oncotherapy through multidimensional reactivity pathways of Fe-protoporphyrin-based hybrid metal-organic frameworks (FTPs, as the core), including photodynamic/chemodynamic-like, catalase-like and glutathione peroxidase-like activities. Meanwhile, owing to the advantages of long circulation abilities of RBCs provided by their cell membranes (RBCMs), FTP with a surface coated with RBCMs (FTP@RBCM) could enormously accumulate at tumor site to achieve remarkably enhanced therapeutic efficiency. Intriguingly, this ROS-mediated dynamic therapy was demonstrated to induce acute local inflammation and high immunogenic cancer death, which evoked a systemic antitumor immune response when combined with the newly identified T cell immunoglobulin and mucin-containing molecule 3 (Tim-3) checkpoint blockade, leading to not only effective elimination of primary tumors but also an abscopal effect of growth suppression of distant tumors. Therefore, such RBC-mimic nanocatalysts with multidimensional catalytic capacities might provide a promising new insight into synergistic cancer treatment.

Engineered Red Blood Cell Biomimetic Nanovesicle with Oxygen Self-Supply for Near-Infrared-II Fluorescence-Guided Synergetic Chemo-Photodynamic Therapy against Hypoxic Tumors

The low bioavailability of photosensitizers (PSs) and the hypoxia nature of tumors often limit the efficacy of current photodynamic therapy (PDT). Therefore, improving the utilization of three essential components (PS, light, and O2) in tumors will enhance PDT efficacy substantially. Herein, we have developed a red blood cell (RBC) biomimetic theranostic nanovesicle (named SPN-Hb@RBCM) with improved photostability, accumulation of PSs, and oxygen self-supply ability to enhance PDT efficacy upon near-infrared (NIR) laser irradiation. Such a biomimetic nanovesicle was prepared by a red blood cell membrane (RBCM)-camouflaged hemoglobin (Hb)-linked semiconducting polymer nanoparticle (SPN-Hb). The RBCM coating enables the long-term circulation of SPN-Hb due to the membrane-mediated immune evasion, allowing for more effective PS accumulation in tumors. Under 808 nm laser irradiation, the photostable SPN can serve as both a photodynamic and a second-near-infrared-window (NIR-II) fluorescence imaging agent; meanwhile, the conjugated Hb can be used as an oxygen carrier to relieve tumor hypoxia for enhancing PDT efficacy. In addition, Hb can also react with the tumor microenvironment overproduced H2O2 to generate cytotoxic hydroxyl radicals (•OHs) for chemodynamic therapy (CDT), which further achieve synergistic effects for PDT. Thus, this study proposed a promising biomimetic theranostic nanoagent for enhancing tumor oxygenation and NIR-II fluorescence-guided synergetic CDT/PDT against hypoxic tumors.

Erythrocyte membrane-camouflaged nanoworms with on-demand antibiotic release for eradicating biofilms using near-infrared irradiation

The increase in the number of resistant bacteria caused by the abuse of antibiotics and the emergence of biofilms significantly reduce the effectiveness of antibiotics. Bacterial infections are detrimental to our life and health. To reduce the abuse of antibiotics and treat biofilm-related bacterial infections, a biomimetic nano-antibacterial system, RBCM-NW-G namely, that controls the release of antibiotics through near infrared was prepared. The hollow porous structure and the high surface activity of nanoworms are used to realize antibiotic loading, and then, biomimetics are applied with red blood cell membranes (RBCM). RBCM-NW-G, which retains the performance of RBCM, shows enhanced permeability and retention effects. Fluorescence imaging in mice showed the effective accumulation of RBCM-NW-G at the site of infection. In addition, the biomimetic nanoparticles showed a longer blood circulation time and good biocompatibility. Anti-biofilm test results showed damage to biofilms due to a photothermal effect and a highly efficient antibacterial performance under the synergy of the photothermal effect, silver iron, and antibiotics. Finally, by constructing a mouse infection model, the great potential of RBCM-NW-G in the treatment of in vivo infections was confirmed.

Synthesized nanoparticles, biomimetic nanoparticles and extracellular vesicles for treatment of autoimmune disease: Comparison and prospect

An emerging strategy is needed to treat autoimmune diseases, many of which are chronic with no definitive cure. Current treatments only alleviate symptoms and have many side effects affecting patient quality of life. Recently, nanoparticle drug delivery systems, an emerging method in medicine, has been used to target cells or organs, without damaging normal tissue. This approach has led to fewer side effects, along with a strong immunosuppressive capacity. Therefore, a nanotechnology approach may help to improve the treatment of autoimmune diseases. In this review, we separated nanoparticles into three categories: synthesized nanoparticles, biomimetic nanoparticles, and extracellular vesicles. This review firstly compares the typical mechanism of action of these three nanoparticle categories respectively in terms of active targeting, camouflage effect, and similarity to parent cells. Then their immunomodulation properties are discussed. Finally, the challenges faced by all these nanoparticles are described.

Recent Progress on NIR-II Photothermal Therapy

Photothermal therapy is a very promising treatment method in the field of cancer therapy. The photothermal nanomaterials in near-infrared region (NIR-I, 750-900 nm) attracts extensive attention in recent years because of the good biological penetration of NIR light. However, the penetration depth is still not enough for solid tumors due to high tissue scattering. The light in the second near-infrared region (NIR-II, 1000-1700 nm) allows deeper tissue penetration, higher upper limit of radiation and greater tissue tolerance than that in the NIR-I, and it shows greater application potential in photothermal conversion. This review summarizes the photothermal properties of Au nanomaterials, two-dimensional materials, metal oxide sulfides and polymers in the NIR-II and their application prospects in photothermal therapy. It will arouse the interest of scientists in the field of cancer treatment as well as nanomedicine.

The Fate of Nanoparticles In Vivo and the Strategy of Designing Stealth Nanoparticle for Drug Delivery

Nano-drug delivery systems (Nano-DDS) offer powerful advantages in drug delivery and targeted therapy for diseases. Compared to the traditional drug formulations, Nano-DDS can increase solubility, biocompatibility, and reduce off-targeted side effects of free drugs. However, they still have some disadvantages that pose a limitation in reaching their full potential in clinical use. Protein adsorption in blood, activation of the complement system, and subsequent sequestration by the mononuclear phagocyte system (MPS) consequently result in nanoparticles (NPs) to be rapidly cleared from circulation. Therefore, NPs have low drug delivery efficiency. So, it is important to develop stealth NPs for reducing bio-nano interaction. In this review, we first conclude the interaction between NPs and biological environments, such as blood proteins and MPS, and factors influencing each other. Next, we will summarize the new strategies to reduce NPs protein adsorption and uptake by the MPS based on current knowledge of the bio-nano interaction. Further directions will also be highlighted for the development of biomimetic stealth nano-delivery systems by combining targeted strategies for a better therapeutic effect.

Erythrocyte membrane bioengineered nanoprobes via indocyanine green-directed assembly for single NIR laser-induced efficient photodynamic/photothermal theranostics

Traditional combinational photodynamic therapy (PDT) and photothermal therapy (PTT) were limited in clinical therapy of cancer due to exceptionally low drug payload and activation by light with separate wavelengths. We have accidentally discovered that zinc phthalocyanine (ZNPC, a typical hydrophobic photosensitizer) and indocyanine green (ICG, a clinically approved fluorescence probe) could be co-assembled into carrier-free nanodrugs (almost 100 wt%) for single NIR laser-induced efficient PDT/PTT. Interestingly, ICG could act as "transformers" for modulating the geometric shape of ZNPC/ICG co-assembling structures from needle-like/spindle-like structure via cubic structure finally to spherical structure. Unfortunately, the nanodrugs suffered from rapid immune clearance. The ZNPC-ICG nanoprobes were further embedded into the erythrocyte membrane (RBC)-camouflaged framework. The designed ZNPC-ICG@RBC could be efficiently accumulated within the tumor sites (continue for ~60 h) and rapidly internalized into cancer cells upon laser irradiation rather than macrophage RAW264.7 cells. Compared with the free ZnPC or ICG, the biomimetic ZNPC-ICG@RBC nanoprobes exhibited amplified therapeutic effects by simultaneously producing ROS and hyperthermia, thereby synergistically improving antitumor efficiency and eliminating the tumors without any regrowth under the guidance of fluorescence imaging. The co-delivery of ZnPC and ICG via a biomimetic carrier-free system might be a promising strategy for bimodal phototherapy of cancer.

Intravital NIR-II three-dimensional photoacoustic imaging of biomineralized copper sulfide nanoprobes

Photoacoustic (PA) imaging with functional nanoprobes in the second near-infrared region (NIR-II, 1000-1700 nm) has aroused much interest due to its deep tissue penetration and high maximum laser permissible exposure. However, most NIR-II PA imaging is performed using the two-dimensional (2D) imaging modality, which impedes the comprehension of the in vivo biodistribution, angiography and molecular-targeted performance of NIR-II nanoprobes (NPs). Herein, we report the systematic monitoring of biomineralized copper sulfide (CuS) NPs, typical NIR-II NPs, in mouse models by employing NIR-II three-dimensional (3D) PA imaging. The advanced imaging modality provides dynamic information about the 3D biodistribution and metabolic pathway of CuS NPs. We also achieved contrast-enhanced 3D PA imaging of abdominal and cerebral vessels at a high signal-to-background ratio. Moreover, the tumor-targeted CuS NPs conjugated with the bombesin peptide endowed NIR-II 3D PA with superior performance in imaging orthotopic tumors both deep in the prostate and in the brain beneath the intact scalp and skull. Our results highlight the potential of NIR-II 3D PA imaging for the evaluation of the in vivo behavior of NPs, thus providing a promising strategy for screening NPs in clinical translational studies.

Active-Targeting NIR-II Phototheranostics in Multiple Tumor Models Using Platelet-Camouflaged Nanoprobes

Cancer phototheranostics in the second near-infrared window (NIR-II, 1000-1700 nm) has recently attracted much attention owing to its high efficacy and good safety compared with that in the first near-infrared window (NIR-I, 650-950 nm). However, the lack of theranostic nanoagents with active-targeting features limits its further application in cancer precision therapies. Herein, we constructed platelet-camouflaged nanoprobes with active-targeting characteristics for NIR-II cancer phototheranostics. The as-prepared biomimetic nanoprobes can not only escape phagocytosis by macrophages but also specifically bind to CD44 on the surface of most cancer cells. We evaluated the active-targeting performance of biomimetic nanoprobes in pancreatic cancer, breast cancer, and glioma mouse models and achieved NIR-II photoacoustic imaging with a high signal-to-background ratio and photothermal treatment with excellent tumor growth inhibition. Our results show the great potential of platelet-camouflaged nanoprobes with NIR-II active-targeting features for cancer precision diagnosis and efficient therapies.

A thieno-isoindigo derivative-based conjugated polymer nanoparticle for photothermal therapy in the NIR-II bio-window

Photothermal therapy (PTT), a powerful tool for non-invasive cancer treatment, has been recognized as an alternative strategy for cancer therapy in the clinic, and it is promoted by optical absorbing agents (photothermal agents) that can intensively convert near-infrared (NIR) light into thermal energy for cancer ablation. Conjugated polymer nanoparticles (CPNs) have recently attracted extensive attention owing to their excellent photothermal properties. However, the absorption of typical CPNs is mostly located in the traditional near-infrared region (NIR-I, 700-900 nm), which suffers from low tissue penetration, so the penetration depth is still limited and severely restricts their further applications. Compared with the NIR-I light, the second near-infrared window light (NIR-II, 1000-1700 nm) could efficiently enhance the tissue penetration depth, however, CPNs which absorb NIR-II region light are still especially limited and need further exploration. Here, a thieno-isoindigo derivative-based Donor-Acceptor (D-A) polymer (BTPBFDTS), which exhibited excellent absorption characteristics from the NIR-I to NIR-II window, was prepared. After formation of nanoparticles and surface functionalization, the prepared nanoparticles (NPsBTPBFDTS@HA NPs) exhibited obvious targeting ability, high photothermal conversion efficiency and photoacoustic imaging effects under 1064 nm irradiation. Both in vitro and in vivo studies demonstrate that our obtained NPsBTPBFDTS@HA nanoparticles possess excellent PTT efficacy including extremely high cancer cell killing ability and admirable tumor elimination efficiency. Hence, this work developed a promising photothermal conversion agent based on CPNs for cancer ablation.