Design of Smart Size-, Surface-, and Shape-Switching Nanoparticles to Improve Therapeutic Efficacy

Towards a switchable nanoparticle behavior using inverse electron-demand Diels-Alder chemistry and ectoenzyme-based ligand activation

Nanoparticles (NPs) as drug delivery platforms encounter numerous obstacles on their journey from administration to the target site. Often, diametrically opposing particle properties are desirable to overcome biological and physical barriers. Therefore, stimuli-responsive NPs have been developed to allow for specific particle adaptation. In this work, it was demonstrated that NPs can be rendered switchable with respect to their interaction with a receptor through an external chemical stimulus. A combination of the inverse electron-demand Diels-Alder (iEDDA) reaction for subsequent NP functionalization and ectoenzyme-based ligand activation allowed for specific particle tailoring. Building on this, a two-step process for target cell recognition was developed. First, NPs were functionalized with Angiotensin-I (Ang-I) as inactive ligand using iEDDA chemistry. At the target site, the ligand was enzymatically processed to Angiotensin-ll (Ang-II) by cellular ectoenzymes. Ang-ll binds as active ligand to the angiotensin ll type 1 (AT1) receptor on the target cell surface. This enzymatic activation aims to minimize the biological effect of the ligand prior to particle binding, while the NP target cell specificity is increased by a two-step recognition with enzymatic processing and receptor binding.

"All-in-One" MnO2@PtAuRu Nanoreactor for Self-Replenishing and Cascade Catalytic Therapy of Cancer

Limited by the insufficient catalytic substrates such as H2O2 and O2 in the tumor microenvironment (TME), the continual propelling of nanozymes catalysis therapy of cancer remains a challenge. Here, an all-in-one MnO2@PtAuRu nanoreactor is constructed for self-propelled and cascade catalytic therapy of tumors. The MnO2@PtAuRu is constructed by using hollow MnO2 (≈150 nm) as the core-carrier and ultrasmall PtAuRu nanoclusters (≈2 nm) anchoring on the surface MnO2. According to the glucose oxidase (GOD)/catalase (CAT)/peroxidase (POD) mimic multienzyme activity of PtAuRu nanoclusters, cascaded nanocatalytic reactions can be self-replenishing to persistently produce •OH for superior chemodynamic therapy (CDT). Additionally, the MnO2 carrier can protect the ultrasmall PtAuRu nanoclusters during the circulation and the overexpressed glutathione (GSH) in the tumor can also be degraded by the MnO2 to synergy the CDT. The MnO2@PtAuRu displays obvious photothermal properties which further enhance the cascade catalytic ability and synergistic therapeutic effect. Therefore, this all-in-one nanozyme provides a promising strategy for the rational design of self-replenishment and self-replenishing cascade catalytic therapy of cancer.

Microenvironment Self-Adaptive Nanomedicine Promotes Spinal Cord Repair by Suppressing Inflammation Cascade and Neural Apoptosis

Despite various biomaterial-based strategies are tried in spinal cord injury (SCI), developing safe and effective microinvasive pharmacotherapy strategies is still an unmet clinical need. Stimuli-responsive nanomedicine has emerged as a promising non-invasion technology, which enhances drug delivery and promotes functional recovery following SCI. Considering the multiple progressive pathological events and the blood spinal cord barrier (BSCB) associating SCI, a microenvironment self-adaptive nanoparticle (custom-designed with rabies virus glycoprotein 29-RVG29 and hyaluronic acid-HA, RHNP) capable of consistently crossing the BSCB and selectively targeting inflammatory cells and neural cells based on different stages of SCI are developed. The data indicated that RHNP can effectively traverse the BSCB through RVG29, and adaptively modulate cellular internalization by selectively exposing either HA or RVG29 through diselenide bonds, depending on pathological reactive oxygen species (ROS) signals. Furthermore, curcumin is loaded into RHNP (RHNP-Cur) to improve motor function and coordination of hind-limbs in a traumatic SCI mouse model. This study finds that RHNP-Cur exhibited inhibitory effects on the inflammatory cascade originating from M1 microglia/macrophages and neurotoxic astrocytes, and protected neural cells from inflammation-induced apoptosis during nerve regeneration. Collectively, the work provides a microenvironment self-adaptive nanomedicine which enables efficient microinvasive treatment of SCI.

Nanomaterial-assisted delivery of CpG oligodeoxynucleotides for boosting cancer immunotherapy

Cancer immunotherapy aims to improve immunity to not only eliminate the primary tumor but also inhibit metastasis and recurrence. It is considered an extremely promising therapeutic approach that breaks free from the traditional paradigm of oncological treatment. As the medical community learns more about the immune system's mechanisms that "turn off the brake" and "step on the throttle", there is increasingly successful research on immunomodulators. However, there are still more restrictions than countermeasures with immunotherapy related to immunomodulators, such as low responsiveness and immune-related adverse events that cause multiple adverse reactions. Therefore, medical experts and materials scientists attempted to the efficacy of immunomodulatory treatments through various methods, especially nanomaterial-assisted strategies. CpG oligodeoxynucleotides (CpG) not only act as an adjuvant to promote immune responses, but also induce autophagy. In this review, the enhancement of immunotherapy using nanomaterial-based CpG formulations is systematically elaborated, with a focus on the delivery, protection, synergistic promotion of CpG efficacy by nanomaterials, and selection of the timing of treatment. In addition, we also discuss and prospect the existing problems and future directions of research on nanomaterials in auxiliary CpG therapy.

Endocytosis: the match point of nanoparticle-based cancer therapy

Nanomedicine has inspired a ground-breaking strategy for cancer therapy. By intelligently assembling diverse moieties to form nanoparticles, numerous functionalities such as controlled release, synergistic efficiency, and in situ killing can be achieved. The emerging nanoparticles have been designed with elevated targeting efficiency as targeting cancer cells is the primary requirement for nanoparticles. However, effective targeting does not guarantee therapeutic effects as endocytosis is a prerequisite for nanoparticles to exert effects. The recent decade has witnessed the rapid development of endocytosis-oriented nanoparticles, and this review subtly analyzes, categorizes, and exemplifies these nanoparticles according to their biological internalization patterns, and the correlation between the endocytosis mechanism and the property of nanoparticles is bridged. Based on the interdisciplinary vision, the present challenges and future perspectives of nanoparticle design for successful endocytosis are discussed, highlighting the potential strategies for the future development of endocytosis-oriented nanoparticles, thus facilitating the endocytosis-oriented strategy from bench to bedside. The undeniable fact is that endocytosis-oriented nanoparticles will definitely bring new blood to the next generation of advanced cancer therapies.

Black phosphorus for bone regeneration: Mechanisms involved and influencing factors

BP has shown good potential for promoting bone regeneration. However, the understanding of the mechanisms of BP-enhanced bone regeneration is still limited. This review first summarizes the recent advances in applications of BP in bone regeneration. We further highlight the possibility that BP enhances bone regeneration by regulating the behavior of mesenchymal stem cells (MSCs), osteoblasts, vascular endothelial cells (VECs), and macrophages, mainly through the regulation of cytoskeletal remodeling, energy metabolism, oxidation resistance and surface adsorption properties, etc. In addition, moderating the physicochemical properties of BP (i.e., shape, size, and surface charge) can alter the effects of BP on bone regeneration. This review reveals the underlying mechanisms of BP-enhanced bone regeneration and provides strategies for further material design of BP-based materials for bone regeneration.

Impact of inorganic/organic nanomaterials on the immune system for disease treatment

The study of nanomaterials' nature, function, and biocompatibility highlights their potential in drug delivery, imaging, diagnostics, and therapeutics. Advancements in nanotechnology have fostered the development and application of diverse nanomaterials. These materials facilitate drug delivery and influence the immune system directly. Yet, understanding of their impact on the immune system is incomplete, underscoring the need to select materials to achieve desired outcomes carefully. In this review, we outline and summarize the distinctive characteristics and effector functions of inorganic nanomaterials and organic materials in inducing immune responses. We highlight the role and advantages of nanomaterial-induced immune responses in the treatment of immune-related diseases. Finally, we briefly discuss the current challenges and future opportunities for disease treatment and clinical translation of these nanomaterials.

Supramolecularly-Cross-Linked Nanogel Assemblies for On-Demand, Ultrasound-Triggered Chemotherapy

Stimulating the release of small nanoparticles (NPs) from a larger NP via the application of an exogenous stimulus offers the potential to address the different size requirements for circulation versus penetration that hinder chemotherapeutic drug delivery. Herein, we report a size-switching nanoassembly-based drug delivery system comprised of ultrasmall starch nanoparticles (SNPs, ∼20-50 nm major size fraction) encapsulated in a poly(oligo(ethylene glycol) methyl ether methacrylate) nanogel (POEGMA, ∼150 nm major size fraction) cross-linked via supramolecular PEG/α-cyclodextrin (α-CD) interactions. Upon heating the nanogel using a non-invasive, high-intensity focused ultrasound (HIFU) trigger, the thermoresponsive POEGMA-CD nanoassemblies are locally de-cross-linked, inducing in situ release of the highly penetrative drug-loaded SNPs. HIFU triggering increased the release of nanoassembly-loaded DOX from 17 to 37% after 3 h, a result correlated with significantly more effective tumor killing relative to nanoassemblies in the absence of HIFU or drug alone. Furthermore, 1.5× more total fluorescence was observed inside a tumor spheroid when nanoassemblies prepared with fluorophore-labeled SNPs were triggered with HIFU relative to the absence of HIFU. We anticipate this strategy holds promise for delivering tunable doses of chemotherapeutic drugs both at and within a tumor site using a non-invasive triggering approach.

Targeting pentamidine towards CD44-overexpressing cells using hyaluronated lipid-polymer hybrid nanoparticles

Biodegradable nanocarriers possess enormous potential for use as drug delivery systems that can accomplish controlled and targeted drug release, and a wide range of nanosystems have been reported for the treatment and/or diagnosis of various diseases and disorders. Of the various nanocarriers currently available, liposomes and polymer nanoparticles have been extensively studied and some formulations have already reached the market. However, a combination of properties to create a single hybrid system can give these carriers significant advantages, such as improvement in encapsulation efficacy, higher stability, and active targeting towards specific cells or tissues, over lipid or polymer-based platforms. To this aim, this work presents the formulation of poly(lactic-co-glycolic) acid (PLGA) nanoparticles in the presence of a hyaluronic acid (HA)-phospholipid conjugate (HA-DPPE), which was used to anchor HA onto the nanoparticle surface and therefore create an actively targeted hybrid nanosystem. Furthermore, ionic interactions have been proposed for drug encapsulation, leading us to select the free base form of pentamidine (PTM-B) as the model drug. We herein report the preparation of hybrid nanocarriers that were loaded via ion-pairing between the negatively charged PLGA and HA and the positively charged PTM-B, demonstrating an improved loading capacity compared to PLGA-based nanoparticles. The nanocarriers displayed a size of below 150 nm, a negative zeta potential of -35 mV, a core-shell internal arrangement and high encapsulation efficiency (90%). Finally, the ability to be taken up and exert preferential and receptor-mediated cytotoxicity on cancer cells that overexpress the HA specific receptor (CD44) has been evaluated. Competition assays supported the hypothesis that PLGA/HA-DPPE nanoparticles deliver their cargo within cells in a CD44-dependent manner.

Exploring non-cytotoxic, antioxidant, and anti-inflammatory properties of selenium nanoparticles synthesized from Gymnema sylvestre and Cinnamon cassia extracts for herbal nanomedicine

The increasing need for pharmaceutical agents that possess attributes such as safety, cost-effectiveness, environmental sustainability, and absence of side effects has driven the advancement of nanomedicine research, which lies at the convergence of nanotechnology and medicine.

AIMS AND OBJECTIVES

The study aimed to synthesize non-toxic selenium nanoparticles (SeNPs) using Gymnema sylvestre (G. sylvestre) and Cinnamon cassia (C. cassia) extracts. It also sought to develop and evaluate versatile nanomedicine formulations i.e. selenium nanoparticles of G. sylvestre and C. cassia (SeNPs), drug (lupeol) loaded SeNPs (DLSeNPs), drug-loaded and coated (PEG) SeNPs (DLCSeNPs) without side effects.

METHODS

The SeNPs formulations were hydrothermally synthesized, loaded with lupeol to improve efficacy, coated with polyethylene glycol (PEG) for targeted delivery, and characterized using UV-Vis spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), zeta potential analysis, size distribution analysis, and X-ray diffraction (XRD). Hemolytic cytotoxicity, 2,2-Diphenyl-1-picrylhydzayl (DPPH), total Reducing power, and total antioxidant capacity (TAC) antioxidant assays, carrageenan-induced paw edema, and histological studies were used to estimate the acute anti-inflammatory activity of the synthesized SeNPs.

RESULTS

The final form of PEGylated and drug (lupeol)-loaded selenium nanoparticles (DLCSeNPs) exhibited an average particle size ranging from 100 to 500 nm as evidenced by SEM, and Zeta potential results. These nanoparticles demonstrated no cytotoxic effects and displayed remarkable antioxidant (IC50 values 19.29) and anti-inflammatory capabilities. These results were fed into Graph-pad Prism 5 software and analyzed by one-way ANOVA, followed by Tukey's post hoc test (p < 0.001). All nano-formulations exhibited significant overall antioxidant activity, with IC50 values ≤ 386 (p < 0.05) as analyzed by ANOVA. The study's results suggest that G. sylvestre outperformed C. cassia in terms of reducing 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical, potassium ferricyanide, and ammonium molybdate in respective antioxidant assays. As far as anti-inflammatory activities are concerned drug (lupeol)-loaded and PEG-coated G. sylvestre SeNPs exhibited the highest anti-inflammatory potential from all other nano-formulations including drug (lupeol)-loaded and PEG-coated C. cassia SeNPs, as exhibited to reduce the release of pro-inflammatory signals i.e. cytokines and NF-kB, making them innovative anti-inflammatory nanomedicine.

CONCLUSION

The study synthesized lupeol-loaded and PEG-coated SeNPs, showcasing the potential for biocompatible, cost-effective anti-inflammatory nanomedicines. G. Sylvester's superior antioxidant and anti-inflammatory performance than Cinnamon cassia emphasizes medicinal plant versatility.

Development of a Specific Aptamer-Modified Nano-System to Treat Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a prevalent gastrointestinal cancer characterized by high mortality and an unfavorable prognosis. While combination therapies involving surgery, chemotherapy, and radiation therapy are advancing, targeted therapy for ESCC remains underdeveloped. As a result, the overall five-year survival rate for ESCC is still below 20%. Herein, ESCC-specific DNA aptamers and an innovative aptamer-modified nano-system is introduced for targeted drug and gene delivery to effectively inhibit ESCC. The EA1 ssDNA aptamer, which binds robustly to ESCC cells with high specificity and affinity, is identified using cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX). An EA1-modified nano-system is developed using a natural egg yolk lipid nanovector (EA1-EYLNs-PTX/siEFNA1) that concurrently loads paclitaxel (PTX) and a small interfering RNA of Ephrin A1 (EFNA1). This combination counters ESCC's proliferation, migration, invasion, and lung metastasis. Notably, EFNA1 is overexpressed in ESCC tumors with lung metastasis and has an inverse correlation with ESCC patient prognosis. The EA1-EYLNs-PTX/siEFNA1 nano-system offers effective drug delivery and tumor targeting, resulting in significantly improved therapeutic efficacy against ESCC tumors. These insights suggest that aptamer-modified nano-systems can deliver drugs and genes with superior tumor-targeting, potentially revolutionizing targeted therapy in ESCC.

Autologous patient-derived exhausted nano T-cells exploit tumor immune evasion to engage an effective cancer therapy

BACKGROUND

Active targeting by surface-modified nanoplatforms enables a more precise and elevated accumulation of nanoparticles within the tumor, thereby enhancing drug delivery and efficacy for a successful cancer treatment. However, surface functionalization involves complex procedures that increase costs and timelines, presenting challenges for clinical implementation. Biomimetic nanoparticles (BNPs) have emerged as unique drug delivery platforms that overcome the limitations of actively targeted nanoparticles. Nevertheless, BNPs coated with unmodified cells show reduced functionalities such as specific tumor targeting, decreasing the therapeutic efficacy. Those challenges can be overcome by engineering non-patient-derived cells for BNP coating, but these are complex and cost-effective approaches that hinder their wider clinical application. Here we present an immune-driven strategy to improve nanotherapeutic delivery to tumors. Our unique perspective harnesses T-cell exhaustion and tumor immune evasion to develop a groundbreaking new class of BNPs crafted from exhausted T-cells (NExT) of triple-negative breast cancer (TNBC) patients by specific culture methods without sophisticated engineering.

METHODS

NExT were generated by coating PLGA (poly(lactic-co-glycolic acid)) nanoparticles with TNBC-derived T-cells exhausted in vitro by acute activation. Physicochemical characterization of NExT was made by dynamic light scattering, electrophoretic light scattering and transmission electron microscopy, and preservation and orientation of immune checkpoint receptors by flow cytometry. The efficacy of chemotherapy-loaded NExT was assessed in TNBC cell lines in vitro. In vivo toxicity was made in CD1 mice. Biodistribution and therapeutic activity of NExT were determined in cell-line- and autologous patient-derived xenografts in immunodeficient mice.

RESULTS

We report a cost-effective approach with a good performance that provides NExT naturally endowed with immune checkpoint receptors (PD1, LAG3, TIM3), augmenting specific tumor targeting by engaging cognate ligands, enhancing the therapeutic efficacy of chemotherapy, and disrupting the PD1/PDL1 axis in an immunotherapy-like way. Autologous patient-derived NExT revealed exceptional intratumor accumulation, heightened chemotherapeutic index and efficiency, and targeted the tumor stroma in a PDL1+ patient-derived xenograft model of triple-negative breast cancer.

CONCLUSIONS

These advantages underline the potential of autologous patient-derived NExT to revolutionize tailored adoptive cancer nanotherapy and chemoimmunotherapy, which endorses their widespread clinical application of autologous patient-derived NExT.

Aerosol inhalation of inflammatory cells-targeted dendrimer-dexamethasone conjugate for efficient allergic asthma therapy

Allergic asthma (AA) is a common breathing disorder clinically characterized by the high occurrence of acute and continuous inflammation. However, the current treatment options for AA are lacking in effectiveness and diversity. In this study, we determined that the cell membrane receptor of gamma-glutamyl transferase (GGT) was highly overexpressed on the inflammatory cells that infiltrate the pulmonary tissues in AA cases. Therefore, we developed a GGT-specific dendrimer-dexamethasone conjugate (GSHDDC) that could be administered via aerosol inhalation to treat AA in a rapid and sustained manner. The GSHDDC was fabricated by the covalent attachment of 6-hydroxyhexyl acrylate-modified dexamethasone to polyamidoamine dendrimers via a carbonic ester linkage and the amino Michael addition, followed by the surface modification of the dendrimers with the GGT substrate of glutathione. After aerosol inhalation by the AA mice, the small particle-sized GSHDDC could easily diffuse into pulmonary alveoli and touch with the inflammatory cells via the glutathione ligand/GGT receptor-mediated recognition. The overexpressed GGT on the surface of inflammatory cells then triggers the gamma-glutamyl transfer reactions of glutathione to generate positively charged primary amines, thereby inducing rapid cationization-mediated cellular endocytosis into the inflammatory cells. The dexamethasone was gradually released by the intracellular enzyme hydrolysis, enabling sustained anti-inflammatory effects (e.g., reducing eosinophil infiltration, decreasing the levels of inflammatory factors) in the ovalbumin-induced AA mice. This study demonstrates the effectiveness of an inhalational and active inflammatory cells-targeted dendrimer-dexamethasone conjugate for efficient AA therapy.

Effects of miR-214 on adenosine A2A receptor and carboxymethyl chitosan nanoparticles on the function of keloid fibroblasts and their mechanisms

This work prepared and investigated the impact of carboxymethyl chitosan nanoparticles (MC-NPs) on the proliferative capability of keloid fibroblasts (KFBs) while analyzing the mechanistic roles of miR-214 and adenosine A2A receptor (A2AR) in fibroblasts within hypertrophic scars. MC-NPs were synthesized through ion cross-linking, were characterized using transmission electron microscopy (TEM) and laser particle size scattering. The influence of MC-NPs on the proliferation capacity of KFBs was assessed using the MTT method. Changes in the expression levels of miR-214 and A2AR in KFBs, normal skin fibroblasts (NFBs), hypertrophic scar tissue, and normal skin tissue were analyzed. KFBs were categorized into anti-miR-214, anti-miR-NC, miR-214 mimics, miR-NC, si-A2AR, si-con, anti-miR-214+ si-con, and anti-miR-214+ si-A2AR groups. Bioinformatics target prediction was conducted to explore the interaction between miR-214 and A2AR. Real-time quantitative PCR and immunoblotting (WB) were employed to detect the expression levels of miR-214, A2AR, apoptotic protein Bax, and TGF-β in different cells. Cell counting kit-8 (CCK8) and flow cytometry were employed to assess cell proliferation activity and apoptosis. The results indicated that MC-NPs exhibited spherical particles with an average diameter of 236.47 ± 4.98 nm. The cell OD value in the MC-NPs group was lower than that in KFBs (P < 0.05). The mRNA levels of miR-214 in KFBs and hypertrophic scar tissue were lower than those in NFBs and normal tissue (P < 0.001), while the mRNA and protein levels of A2AR were significantly elevated (P < 0.05). Compared to the control group and anti-miR-NC, the anti-miR-214 group showed significantly increased cell OD values and Bcl-2 protein expression (P < 0.001), decreased levels of apoptotic gene Bax protein, TGF-β gene mRNA, and protein expression (P < 0.001). Continuous complementary binding sites were identified between miR-214 and A2AR. Compared to the control group, the si-A2AR group exhibited a significant decrease in A2AR gene mRNA and protein expression levels (P < 0.001), reduced cell viability (P < 0.001), increased apoptosis rate (P < 0.001), and a significant elevation in TGF-β protein expression (P < 0.001). miR-214 targetedly regulated the expression of A2AR, inducing changes in TGF-β content, promoting the proliferation of keloid fibroblasts, and inhibiting cell apoptosis.

Recent advances in nano/micro systems for improved circulation stability, enhanced tumor targeting, penetration, and intracellular drug delivery: a review

In recent years, nanoparticles (NPs) have been extensively developed as drug carriers to overcome the limitations of cancer therapeutics. However, there are several biological barriers to nanomedicines, which include the lack of stability in circulation, limited target specificity, low penetration into tumors and insufficient cellular uptake, restricting the active targeting toward tumors of nanomedicines. To address these challenges, a variety of promising strategies were developed recently, as they can be designed to improve NP accumulation and penetration in tumor tissues, circulation stability, tumor targeting, and intracellular uptake. In this Review, we summarized nanomaterials developed in recent three years that could be utilized to improve drug delivery for cancer treatments.

Charge-Reversible Nanoparticles: Advanced Delivery Systems for Therapy and Diagnosis

The past two decades have witnessed a rapid progress in the development of surface charge-reversible nanoparticles (NPs) for drug delivery and diagnosis. These NPs are able to elegantly address the polycation dilemma. Converting their surface charge from negative/neutral to positive at the target site, they can substantially improve delivery of drugs and diagnostic agents. By specific stimuli like a shift in pH and redox potential, enzymes, or exogenous stimuli such as light or heat, charge reversal of NP surface can be achieved at the target site. The activated positive surface charge enhances the adhesion of NPs to target cells and facilitates cellular uptake, endosomal escape, and mitochondrial targeting. Because of these properties, the efficacy of incorporated drugs as well as the sensitivity of diagnostic agents can be essentially enhanced. Furthermore, charge-reversible NPs are shown to overcome the biofilm formed by pathogenic bacteria and to shuttle antibiotics directly to the cell membrane of these microorganisms. In this review, the up-to-date design of charge-reversible NPs and their emerging applications in drug delivery and diagnosis are highlighted.

Advances in tumor immunomodulation based on nanodrug delivery systems

Immunotherapy is a therapeutic approach that employs immunological principles and techniques to enhance and amplify the body's immune response, thereby eradicating tumor cells. Immunotherapy has demonstrated effective antitumor effects on a variety of malignant tumors. However, when applied to humans, many immunotherapy drugs fail to target lesions with precision, leading to an array of adverse immune-related reactions that profoundly limit the clinical application of immunotherapy. Nanodrug delivery systems enable the precise delivery of immunotherapeutic drugs to targeted tissues or specific immune cells, enhancing the immune antitumor effect while reducing the number of adverse reactions. A nanodrug delivery system provides a feasible strategy for activating the antitumor immune response by the following mechanisms: 1) increased targeting and uptake of vaccines by DCs, which enhances the efficacy of the immune response; 2) increased tumor cell immunogenicity; 3) regulation of TAMs and other cells by, for example, regulating the polarization of TAMs and interfering with TAN formation, and ECM remodeling by CAFs; and 4) interference with tumor immune escape signaling pathways, namely, the PD-1/PD-L1, FGL1/LAG-3 and IDO signaling pathways. This paper reviews the progress of nanodrug delivery system research with respect to tumor immunotherapy based on tumor immunomodulation over the last few years, discussing the promising future of these delivery systems under this domain.

Selective organ targeting nanoparticles: from design to clinical translation

Targeting nanoparticle is a very promising therapeutic approach that can precisely target specific sites to treat diseases. Research on nanoscale drug delivery systems has made great progress in the past few years, making targeting nanoparticles a promising prospect. However, selective targeting nanoparticles designed for specific organs still face several challenges, one of which is the unknown fate of nanoparticles in vivo. This review starts with the in vivo journey of nanoparticles and describes the biological barriers and some targeting strategies for nanoparticles to target specific organs. Then, through the collection of literature in recent years, the design of selective targeting nanoparticles for various organs is illustrated, which provides a reference strategy for people to study the design of selective organ targeting nanoparticles. Ultimately, the prospect and challenge of selective organ targeting nanoparticles are discussed by collecting the data of clinical trials and marketed drugs.

Nanoparticles with transformable physicochemical properties for overcoming biological barriers

In recent years, tremendous progress has been made in the development of nanomedicines for advanced therapeutics, yet their unsatisfactory targeting ability hinders the further application of nanomedicines. Nanomaterials undergo a series of processes, from intravenous injection to precise delivery at target sites. Each process faces different or even contradictory requirements for nanoparticles to pass through biological barriers. To overcome biological barriers, researchers have been developing nanomedicines with transformable physicochemical properties in recent years. Physicochemical transformability enables nanomedicines to responsively switch their physicochemical properties, including size, shape, surface charge, etc., thus enabling them to cross a series of biological barriers and achieve maximum delivery efficiency. In this review, we summarize recent developments in nanomedicines with transformable physicochemical properties. First, the biological dilemmas faced by nanomedicines are analyzed. Furthermore, the design and synthesis of nanomaterials with transformable physicochemical properties in terms of size, charge, and shape are summarized. Other switchable physicochemical parameters such as mobility, roughness and mechanical properties, which have been sought after most recently, are also discussed. Finally, the prospects and challenges for nanomedicines with transformable physicochemical properties are highlighted.

Nanomedicine in cancer therapy

Cancer remains a highly lethal disease in the world. Currently, either conventional cancer therapies or modern immunotherapies are non-tumor-targeted therapeutic approaches that cannot accurately distinguish malignant cells from healthy ones, giving rise to multiple undesired side effects. Recent advances in nanotechnology, accompanied by our growing understanding of cancer biology and nano-bio interactions, have led to the development of a series of nanocarriers, which aim to improve the therapeutic efficacy while reducing off-target toxicity of the encapsulated anticancer agents through tumor tissue-, cell-, or organelle-specific targeting. However, the vast majority of nanocarriers do not possess hierarchical targeting capability, and their therapeutic indices are often compromised by either poor tumor accumulation, inefficient cellular internalization, or inaccurate subcellular localization. This Review outlines current and prospective strategies in the design of tumor tissue-, cell-, and organelle-targeted cancer nanomedicines, and highlights the latest progress in hierarchical targeting technologies that can dynamically integrate these three different stages of static tumor targeting to maximize therapeutic outcomes. Finally, we briefly discuss the current challenges and future opportunities for the clinical translation of cancer nanomedicines.

In Vivo NIR-II Fluorescence Lifetime Imaging of Whole-Body Vascular Using High Quantum Yield Lanthanide-Doped Nanoparticles

Second near infrared (NIR-II, 1000-1700 nm) fluorescence lifetime imaging is a powerful tool for biosensing, anti-counterfeiting, and multiplex imaging. However, the low photoluminescence quantum yield (PLQY) of fluorescence probes in NIR-II region limits its data collecting efficiency and accuracy, especially in multiplex molecular imaging in vivo. To solve this problem, lanthanide-doped nanoparticles (NPs) β-NaErF4 : 2%Ce@NaYbF4 @NaYF4 with high PLQY and tunable PL lifetime through multi-ion doping and core-shell structural design, are presented. The obtained internal PLQY can reach up to 50.1% in cyclohexane and 9.2% in water under excitation at 980 nm. Inspired by the above results, a fast NIR-II fluorescence lifetime imaging of whole-body vascular in mice is successfully performed by using the homebuilt fluorescence lifetime imaging system, which reveals a murine abdominal capillary network with low background. A further demonstration of fluorescence lifetime multiplex imaging is carried out in molecular imaging of atherosclerosis cells and different organs in vivo through NPs conjugating with specific peptides and different injection modalities, respectively. These results demonstrate that the high PLQY NPs combined with the homebuilt fluorescence lifetime imaging system can realize a fast and high signal-to-noise fluorescence lifetime imaging; thus, opening a road for multiplex molecular imaging of atherosclerosis.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Ligand Chemistry in Antitumor Theranostic Nanoparticles

Theranostic nanoparticles' potential in tumor treatment has been widely acknowledged thanks to their capability of integrating multifaceted functionalities into a single nanosystem. Theranostic nanoparticles are typically equipped with an inorganic core with exploitable physical properties for imaging and therapeutic functions, bioinert coatings for improved biocompatibility and immunological stealth, controlled drug-loading-release modules, and the ability to recognize specific cell type for uptake. Integrating multiple functionalities in a single nanosized construct require sophisticated molecular design and precise execution of assembly procedures. Underlying the multifunctionality of theranostic nanoparticles, ligand chemistry plays a decisive role in translating theoretical designs into fully functionalized theranostic nanoparticles. The ligand hierarchy in theranostic nanoparticles is usually threefold. As they serve to passivate the nanoparticle's surface, capping ligands form the first layer directly interfacing with the crystalline lattice of the inorganic core. The size and shape of nanoparticles are largely determined by the molecular property of capping ligands so that they have profound influences on the nanoparticles' surface chemistry and physical properties. Capping ligands are mostly chemically inert, which necessitates the presence of additional ligands for drug loading and tumor targeting. The second layer is commonly utilized for drug loading. Therapeutic drugs can either be covalently conjugated onto the capping layer or noncovalently loaded onto nanoparticles via drug-loading ligands. Drug-loading ligands need to be equally versatile in properties to accommodate the diversity of drugs. Biodegradable moieties are often incorporated into drug-loading ligands to enable smart drug release. With the aid of targeting ligands which usually stand the tallest on the nanoparticle surface to seek and bind to their corresponding receptors on the target, theranostic nanoparticles can preferentially accumulate at the tumor site to attain a higher precision and quantity for drug delivery. In this Account, the properties and utilities of representative capping ligands, drug-loading ligands, and targeting ligands are reviewed. Since these types of ligands are often assembled in close vicinity to each other, it is essential for them to be chemically compatible and able to function in tandem with each other. Relevant conjugation strategies and critical factors with a significant impact on ligands' performance on nanoparticles are discussed. Representative theranostic nanoparticles are presented to showcase how different types of ligands function synergistically from a single nanosystem. Finally, the technological outlook of evolving ligand chemistry on theranostic nanoparticles is provided.

Nanomaterials for Periodontal Tissue Regeneration: Progress, Challenges and Future Perspectives

Bioactive nanomaterials are increasingly being applied in oral health research. Specifically, they have shown great potential for periodontal tissue regeneration and have substantially improved oral health in translational and clinical applications. However, their limitations and side effects still need to be explored and elucidated. This article aims to review the recent advancements in nanomaterials applied for periodontal tissue regeneration and to discuss future research directions in this field, especially focusing on research using nanomaterials to improve oral health. The biomimetic and physiochemical properties of nanomaterials such as metals and polymer composites are described in detail, including their effects on the regeneration of alveolar bone, periodontal ligament, cementum and gingiva. Finally, the biomedical safety issues of their application as regenerative materials are updated, with a discussion about their complications and future perspectives. Although the applications of bioactive nanomaterials in the oral cavity are still at an initial stage, and pose numerous challenges, recent research suggests that they are a promising alternative in periodontal tissue regeneration.

Disulfide-Cross-Linked Nanogel-Based Nanoassemblies for Chemotherapeutic Drug Delivery

Although nanoparticle-based chemotherapeutic strategies have gained in popularity, the efficacy of such therapies is still limited in part due to the different nanoparticle sizes needed to best accommodate different parts of the drug delivery pathway. Herein, we describe a nanogel-based nanoassembly based on the entrapment of ultrasmall starch nanoparticles (size 10-40 nm) within disulfide-crosslinked chondroitin sulfate-based nanogels (size 150-250 nm) to address this challenge. Upon exposure of the nanoassembly to the reductive tumor microenvironment, the chondroitin sulfate-based nanogel can degrade to release the doxorubicin-loaded starch nanoparticles in the tumor to facilitate improved intratumoral penetration. CT26 colon carcinoma spheroids could be efficiently penetrated by the nanoassembly (resulting in 1 order of magnitude higher DOX-derived fluorescence inside the spheroid relative to free DOX), while in vivo experiments showed that doxorubicin-loaded nanoassemblies reduced tumor sizes by 6× relative to saline controls and 2× relative to free DOX after 21 days. Together, these data suggest that nanogel-based nanoassemblies are a viable option for improving the efficacy and safety of nanoparticle-based drug delivery vehicles treating cancer.

Smart anti-vascular nanoagent induces positive feedback loop for self-augmented tumor accumulation

How to achieve efficient drug accumulation in the tumor with low vascular density is a great challenge but the key to push the limit of anti-vascular therapeutic efficacy. Herein, we report a charge-reversible nanoparticles of gambogenic acid (CRNP-GNA) that would induce the positive feedback loop between increased tumor vascular permeability and improved drug accumulation. This positive feedback loop would remarkably improve tumor vascular permeability for efficient drug accumulation through few residue vessels. As compared to its charge-irreversible analogue in the latter injections, the accumulation in tumor and vascular permeability and retention indexes (VPRI) in CRNP-GNA group respectively boosted from nearly equal to 8.32 and 60 times, while its tumorous microvessel density decreased from nearly equal to only 7%. The self-augmented accumulation consequently amplified the antitumor efficacy via multiple pathways of anti-angiogenesis, vascular disruption and pro-apoptosis, where 5 out of 6 tumors in animal models were completely cured by CRNP-GNA. This work confirms that the underlying positive feedback loop for anti-vascular therapy could be induced by charge-reversible drug delivery nanosystem to achieve efficient and self-augmented drug accumulation even in the tumor with few vessels. It provides a novel strategy to conquer the dilemma between anti-vascular efficacy and drug accumulation.

Dual size/charge-switchable and multi-responsive gelatin-based nanocluster for targeted anti-tumor therapy

Biopolymers with excellent biocompatibility and biodegradability show great potential for designing drug nanocarriers, while it's difficult to fabricate smart vehicles with multiple switching (size, surface, shape) based on biopolymers alone. Here, we report a dual size/charge-switchable and multi-responsive doxorubicin-loaded gelatin-based nanocluster (DOX-icluster) for improved tumor penetration and targeted anti-tumor therapy. The DOX-icluster was electrostatically assembled from folic acid and dimethylmaleic anhydride modified gelatin (FA-GelDMA) and small-sized DOX-loaded NH₂ modified hollow mesoporous organosilicon nanoparticles (DOX-HMON-NH₂). DOX-icluster had an initial size of about 199 nm at neutral pH. After accumulation in tumor tissue, the DMA bond of FA-GelDMA was cleaved and gelatin was degraded by matrix metalloproteinase (MMP-2), thus 48 nm and positively charged DOX-HMON-NH₂ was released to facilitate penetration and cell internalization. DOX-HMON-NH₂ was further degraded by intracellular glutathione (GSH) with releasing 48.1 % of DOX. The cellular uptake results indicated that the fabricated icluster promoted the uptake of DOX by 4T1 cells. With enhanced penetration efficacy, the tumor spheroids volume treated with DOX-icluster was reduced to 15.1 % on day 7. This cytocompatible multi-responsive gelatin-based icluster with size-shrinking and charge-reversible characteristics may be used as a significant drug carrier for tumor therapy.

Biomaterial-based platforms for modulating immune components against cancer and cancer stem cells

Immunotherapy involves the therapeutic alteration of the patient's immune system to identify, target, and eliminate cancer cells. Dendritic cells, macrophages, myeloid-derived suppressor cells, and regulatory T cells make up the tumor microenvironment. In cancer, these immune components (in association with some non-immune cell populations like cancer-associated fibroblasts) are directly altered at a cellular level. By dominating immune cells with molecular cross-talk, cancer cells can proliferate unchecked. Current clinical immunotherapy strategies are limited to conventional adoptive cell therapy or immune checkpoint blockade. Targeting and modulating key immune components presents an effective opportunity. Immunostimulatory drugs are a research hotspot, but their poor pharmacokinetics, low tumor accumulation, and non-specific systemic toxicity limit their use. This review describes the cutting-edge research undertaken in the field of nanotechnology and material science to develop biomaterials-based platforms as effective immunotherapeutics. Various biomaterial types (polymer-based, lipid-based, carbon-based, cell-derived, etc.) and functionalization methodologies for modulating tumor-associated immune/non-immune cells are explored. Additionally, emphasis has been laid on discussing how these platforms can be used against cancer stem cells, a fundamental contributor to chemoresistance, tumor relapse/metastasis, and failure of immunotherapy. Overall, this comprehensive review strives to provide up-to-date information to an audience working at the juncture of biomaterials and cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Cancer immunotherapy possesses incredible potential and has successfully transitioned into a clinically lucrative alternative to conventional anti-cancer therapies. With new immunotherapeutics getting rapid clinical approval, fundamental problems associated with the dynamic nature of the immune system (like limited clinical response rates and autoimmunity-related adverse effects) have remained unanswered. In this context, treatment approaches that focus on modulating the compromised immune components within the tumor microenvironment have garnered significant attention amongst the scientific community. This review aims to provide a critical discussion on how various biomaterials (polymer-based, lipid-based, carbon-based, cell-derived, etc.) can be employed along with immunostimulatory agents to design innovative platforms for selective immunotherapy directed against cancer and cancer stem cells.

Enhancing Methotrexate Delivery in the Brain by Mesoporous Silica Nanoparticles Functionalized with Cell-Penetrating Peptide using in Vivo and ex Vivo Monitoring

The blood-brain barrier (BBB) acts as a physical/biochemical barrier that protects brain parenchyma from potential hazards exerted by different xenobiotics found in the systemic circulation. This barrier is created by "a lipophilic gate" as well as a series of highly organized influx/efflux mechanisms. The BBB bottleneck adversely affects the efficacy of chemotherapeutic agents in treating different CNS malignancies such as glioblastoma, an aggressive type of cancer affecting the brain. In the present study, mesoporous silica nanoparticles (MSNs) were conjugated with the transactivator of transcription (TAT) peptide, a cell-penetrating peptide, to produce MSN-NH-TAT with the aim of improving methotrexate (MTX) penetration into the brain. The TAT-modified nanosystem was characterized by Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and N₂ adsorption-desorption analysis. In vitro hemolysis and cell viability studies confirmed the biocompatibility of the MSN-based nanocarriers. In addition, in vivo studies showed that the MTX-loaded MSN-NH-TAT improved brain-to-plasma concentration ratio, brain uptake clearance, and the drug's blood terminal half-life, compared with the use of free MTX. Taken together, the results of the present study indicate that MSN functionalization with TAT is crucial for delivery of MTX into the brain. The present nanosystem represents a promising alternative drug carrier to deliver MTX into the brain via overcoming the BBB.

A sequentially responsive cascade nanoplatform for increasing chemo-chemodynamic therapy

Poly(lactide-co-glycolide) (PLGA) is promising carrier material for drugs delivery in cancer therapy. However, the slow degradation and lack of targeting have greatly limited the clinical effectiveness of PLGA-based nanomedicines. Herein, we fabricated a hybrid nanosystem (3 P @ He/Pt-NPs) comprising of acid-sensitive polymer (mPOE-PLGA), active-targeting polymer (PBA-PLGA) and therapeutic agents (hemin+cisplatin) to combat these problems. In neutral environment, PEGylation can effectively improve the blood stability and circulation time of hybrid nanosystem. After reaching tumor regions, this nanosystem efficiently increased cellular uptake by dePEGylation and PBA-mediated active-targeting. Furthermore, encapsulated hemin could catalyze the oxygen bubbles generation, which remarkably increasing the drugs release rate. Subsequently, hybrid particles produced a higher cell-killing effect to lung cancer cells (A549) by the combination therapy (chemotherapy and chemodynamic therapy (CDT)). Importantly, cisplatin further amplified CDT effect by inducing H₂O₂ regeneration owing to the cascade enzymatic reactions, while hemin decreased intracellular glutathione (GSH) level, resulting in a low detoxification effect to cisplatin. Thus, hybrid particles could efficiently inhibit drug-resistant tumor growth and the inhibition rate reached 83.2%. Overall, this hybrid polymer nanosystem improve the drawbacks of PLGA-based nanocarriers, and can realize a cascading enhanced tumor treatment.

All-in-one CoFe2O4@Tf nanoagent with GSH depletion and tumor-targeted ability for mutually enhanced chemodynamic/photothermal synergistic therapy

In the complex and severe tumor microenvironment, the antitumor efficiency of nanomedicines is significantly limited by their low-efficacy monotherapy, non-tumor targeting, and systemic toxicity. Herein, to achieve tumor-targeted and enhanced chemodynamic/photothermal therapy (CDT/PTT), we fabricated an "all-in-one" biocompatible transferrin-loaded cobalt ferrate nanoparticle (CoFe₂O₄@Tf (CFOT)) with multiple functions by a simple solvothermal method and the following transferrin (Tf) functionalization. Upon exposure to 808 nm laser irradiation, CFOT, as a novel photothermal agent, exhibited outstanding phototherapeutic activity because of its excellent photothermal conversion efficiency (η = 46.5%) for high-performance PTT. Moreover, CFOT with multiple redox pairs could efficiently convert endogenous H₂O₂ to hazardous hydroxyl radicals (˙OH) via Fenton reactions while scavenging overexpressed GSH in the tumor microenvironment to realize self-reinforcing CDT. Importantly, CFOT undergoes a promoted Fenton-type reaction upon increasing the temperature under a photothermal effect and could augment PTT by high-level ˙OH, exhibiting a considerably enhanced synergistic therapeutic effect. In vitro and in vivo experimental results demonstrated that CFOT has good potential as an "all-in-one" nanoagent to combine photothermal, chemodynamic, and tumor targeting for efficient tumor elimination.

Hypoxia-responsive Immunostimulatory Nanomedicines Synergize with Checkpoint Blockade Immunotherapy for Potentiating Cancer Immunotherapy

Inducing cell death while simultaneously enhancing antitumor immune responses is a promising therapeutic approach for multiple cancers. Celastrol (Cel) and 7-ethyl-10-hydroxycamptothecin (SN38) have contrasting physicochemical properties, but strong synergy in immunogenic cell death induction and anticancer activity. Herein, a hypoxia-sensitive nanosystem (CS@TAP) was designed to demonstrate effective immunotherapy for colorectal cancer by systemic delivery of an immunostimulatory chemotherapy combination. Furthermore, the combination of CS@TAP with anti-PD-L1 mAb (αPD-L1) exhibited a significant therapeutic benefit of delaying tumor growth and increased local doses of immunogenic signaling and T-cell infiltration, ultimately extending survival. We conclude that CS@TAP is an effective inducer of immunogenic cell death (ICD) in cancer immunotherapy. Therefore, this study provides an encouraging strategy to synergistically induce immunogenic cell death to enhance tumor cytotoxic T lymphocytes (CTLs) infiltration for anticancer immunotherapy.

Hypoxia-responsive Immunostimulatory Nanomedicines Synergize with Checkpoint Blockade Immunotherapy for Potentiating Cancer Immunotherapy

Inducing cell death while simultaneously enhancing antitumor immune responses is a promising therapeutic approach for multiple cancers. Celastrol (Cel) and 7-ethyl-10-hydroxycamptothecin (SN38) have contrasting physicochemical properties, but strong synergy in immunogenic cell death induction and anticancer activity. Herein, a hypoxia-sensitive nanosystem (CS@TAP) was designed to demonstrate effective immunotherapy for colorectal cancer by systemic delivery of an immunostimulatory chemotherapy combination. Furthermore, the combination of CS@TAP with anti-PD-L1 mAb (αPD-L1) exhibited a significant therapeutic benefit of delaying tumor growth and increased local doses of immunogenic signaling and T-cell infiltration, ultimately extending survival. We conclude that CS@TAP is an effective inducer of immunogenic cell death (ICD) in cancer immunotherapy. Therefore, this study provides an encouraging strategy to synergistically induce immunogenic cell death to enhance tumor cytotoxic T lymphocytes (CTLs) infiltration for anticancer immunotherapy.

Responsive shape-shifting nanoarchitectonics and its application in tumor diagnosis and therapy

Nanodrug delivery system has a great application in the treatment of solid tumors by virtue of EPR effect, though its success in clinics is still limited by its poor extravasation, small intratumoral accumulation, and weak tumor penetration. The shape of nanoparticles (NPs) greatly affects their circulation time, flow behavior, intratumoral amassing, cell internalization as well as tumor tissue penetration. Generally, short nanorods and 100-200 nm spherical nanocarriers possess nice circulation behaviors, nanorods and nanofibers with a large aspect ratio (AR) cumulate well at tumor sites, and tiny nanospheres/disks (< 50 nm) and short nanorods with a low AR achieve a favorable tumor tissue penetration. The AR and surface evenness of NPs also tune their cell contact, cell ingestion, and drug accumulation at tumor sites. Therefore, adopting stimulus-responsive shape-switching (namely, shape-shifting nanoarchitectonics) can not only ensure a good circulation and extravasation for NPs, but also and more importantly, promote their amassing, retention, and penetration in tumor tissues to maximize therapeutic efficacy. Here we review the recently developed shape-switching nanoarchitectonics of antitumoral NPs based on stimulus-responsiveness, demonstrate how successful they are in tumor shrinking and elimination, and provide new ideas for the optimization of anticancer nanotherapeutics.

"Targeting Design" of Nanoparticles in Tumor Therapy

Tumor-targeted therapy based on nanoparticles is a popular research direction in the biomedical field. After decades of research and development, both the passive targeting ability of the inherent properties of NPs and the active targeting based on ligand receptor interaction have gained deeper understanding. Unfortunately, most targeted delivery strategies are still in the preclinical trial stage, so it is necessary to further study the biological fate of particles in vivo and the interaction mechanism with tumors. This article reviews different targeted delivery strategies based on NPs, and focuses on the physical and chemical properties of NPs (size, morphology, surface and intrinsic properties), ligands (binding number/force, activity and species) and receptors (endocytosis, distribution and recycling) and other factors that affect particle targeting. The limitations and solutions of these factors are further discussed, and a variety of new targeting schemes are introduced, hoping to provide guidance for future targeting design and achieve the purpose of rapid transformation of targeted particles into clinical application.

Biomedical polymers: synthesis, properties, and applications

Biomedical polymers have been extensively developed for promising applications in a lot of biomedical fields, such as therapeutic medicine delivery, disease detection and diagnosis, biosensing, regenerative medicine, and disease treatment. In this review, we summarize the most recent advances in the synthesis and application of biomedical polymers, and discuss the comprehensive understanding of their property-function relationship for corresponding biomedical applications. In particular, a few burgeoning bioactive polymers, such as peptide/biomembrane/microorganism/cell-based biomedical polymers, are also introduced and highlighted as the emerging biomaterials for cancer precision therapy. Furthermore, the foreseeable challenges and outlook of the development of more efficient, healthier and safer biomedical polymers are discussed. We wish this systemic and comprehensive review on highlighting frontier progress of biomedical polymers could inspire and promote new breakthrough in fundamental research and clinical translation.

Using the Intranasal Route to Administer Drugs to Treat Neurological and Psychiatric Illnesses: Rationale, Successes, and Future Needs

While the intranasal administration of drugs to the brain has been gaining both research attention and regulatory success over the past several years, key fundamental and translational challenges remain to fully leveraging the promise of this drug delivery pathway for improving the treatment of various neurological and psychiatric illnesses. In response, this review highlights the current state of understanding of the nose-to-brain drug delivery pathway and how both biological and clinical barriers to drug transport using the pathway can been addressed, as illustrated by demonstrations of how currently approved intranasal sprays leverage these pathways to enable the design of successful therapies. Moving forward, aiming to better exploit the understanding of this fundamental pathway, we also outline the development of nanoparticle systems that show improvement in delivering approved drugs to the brain and how engineered nanoparticle formulations could aid in breakthroughs in terms of delivering emerging drugs and therapeutics while avoiding systemic adverse effects.