Redox dual-stimuli responsive drug delivery systems for improving tumor-targeting ability and reducing adverse side effects

Metal organic framework-based variable-size nanoparticles for tumor microenvironment-responsive drug delivery

Nanoparticles (NPs) have been designed for the treatment of tumors increasingly. However, the drawbacks of single-size NPs are still worth noting, as their circulation and metabolism in the blood are negatively correlated with their accumulation at the tumor site. If the size of single-size NPs is too small, it will be quickly cleared in the blood circulation, while, the size is too large, the distribution of NPs in the tumor site will be reduced, and the widespread distribution of NPs throughout the body will cause systemic toxicity. Therefore, a class of variable-size NPs with metal organic frameworks (MOFs) as the main carrier, and size conversion in compliance with the characteristics of the tumor microenvironment (TME), was designed. MOF-based variable-size NPs can simultaneously extend the time of blood circulation and metabolism, then enhance the targeting ability of the tumor site. In this review, MOF NPs are categorized and exemplified from a new perspective of NP size variation; the advantages, mechanisms, and significance of MOF-based variable-size NPs were summarized, and the potential and challenges in delivering anti-tumor drugs and multimodal combination therapy were discussed.

Engineering dynamic covalent bond-based nanosystems for delivery of antimicrobials against bacterial infections

Nanodrug delivery systems (NDDS) continue to be explored as novel strategies enhance therapy outcomes and combat microbial resistance. The need for the formulation of smart drug delivery systems for targeting infection sites calls for the engineering of responsive chemical designs such as dynamic covalent bonds (DCBs). Stimuli response due to DCBs incorporated into nanosystems are emerging as an alternative way to target infection sites, thus enhancing the delivery of antibacterial agents. This leads to the eradication of bacterial infections and the reduction of antimicrobial resistance. Incorporating DCBs on the backbone of the nanoparticles endows the systems with several properties, including self-healing, controlled disassembly, and stimuli responsiveness, which are beneficial in the delivery and release of the antimicrobial at the infection site. This review provides a comprehensive and current overview of conventional DCBs-based nanosystems, stimuli-responsive DCBs-based nanosystems, and targeted DCBs-based nanosystems that have been reported in the literature for antibacterial delivery. The review emphasizes the DCBs used in their design, the nanomaterials constructed, the drug release-triggering stimuli, and the antibacterial efficacy of the reported DCBs-based nanosystems. Additionally, the review underlines future strategies that can be used to improve the potential of DCBs-based nanosystems to treat bacterial infections and overcome antibacterial resistance.

Artificial viruses: A nanotechnology based approach

OBJECTIVES

The main objective of this work was to review and summarise the detailed literature available on viral nanoparticle and the strategies utilised for their manufacture along with their applications as therapeutic agents.

DATA ACQUISITION

The reported literature related to development and application of virus nanoparticles have been collected from electronic data bases like ScienceDirect, google scholar, PubMed by using key words like "viral nanoparticles", "targeted drug delivery" and "vaccines" and related combinations.

RESULT

From the detailed literature survey, virus nanoparticles were identified as carriers for the targeted delivery. Due to the presence of nanostructures in virus nanoparticles, these protect the drugs from the degradation in the gastrointestinal tract and in case of the delivery of gene medicine, they carry the nucleic acids to the target/susceptible host cells. Thus, artificial viruses are utilised for targeted delivery to specific organ in biomedical and biotechnological areas.

CONCLUSION

Thus, virus nanoparticles can be considered as viable option as drug/gene carrier in various healthcare sectors especially drug delivery and vaccine and can be explored further in future for the development of better drug delivery techniques.

Biomedical Trends in Stimuli-Responsive Hydrogels with Emphasis on Chitosan-Based Formulations

Biomedicine is constantly evolving to ensure a significant and positive impact on healthcare, which has resulted in innovative and distinct requisites such as hydrogels. Chitosan-based formulations stand out for their versatile utilization in drug encapsulation, transport, and controlled release, which is complemented by their biocompatibility, biodegradability, and non-immunogenic nature. Stimuli-responsive hydrogels, also known as smart hydrogels, have strictly regulated release patterns since they respond and adapt based on various external stimuli. Moreover, they can imitate the intrinsic tissues' mechanical, biological, and physicochemical properties. These characteristics allow stimuli-responsive hydrogels to provide cutting-edge, effective, and safe treatment. Constant progress in the field necessitates an up-to-date summary of current trends and breakthroughs in the biomedical application of stimuli-responsive chitosan-based hydrogels, which was the aim of this review. General data about hydrogels sensitive to ions, pH, redox potential, light, electric field, temperature, and magnetic field are recapitulated. Additionally, formulations responsive to multiple stimuli are mentioned. Focusing on chitosan-based smart hydrogels, their multifaceted utilization was thoroughly described. The vast application spectrum encompasses neurological disorders, tumors, wound healing, and dermal infections. Available data on smart chitosan hydrogels strongly support the idea that current approaches and developing novel solutions are worth improving. The present paper constitutes a valuable resource for researchers and practitioners in the currently evolving field.

A review on advancements in the application of starch-based nanomaterials in biomedicine: Precision drug delivery and cancer therapy

The burgeoning field of starch-based nanomaterials in biomedical applications has perceived notable progressions, with a particular emphasis on their pivotal role in precision drug delivery and the inhibition of tumor growth. The complicated challenges in current biomedical research require innovative approaches for improved therapeutic outcomes, prompting an exploration into the possible of starch-based nanomaterials. The conceptualization of this review emerged from recognizing the need for a comprehensive examination of the structural attributes, versatile properties, and mechanisms underlying the efficiency of starch-based nanomaterials in inhibiting tumor growth and enabling targeted drug delivery. This review delineates the substantial growth in utilizing starch-based nanomaterials, elucidating their small size, high surface-volume ratio, and biocompatibility, predominantly emphasizing their possible to actively recognize cancer cells, deliver anticancer drugs, and combat tumors efficiently. The investigation of these nanomaterials encompasses to improving biocompatibility and targeting specific tissues, thereby contributing to the evolving landscape of precision medicine. The review accomplishes by highlighting the auspicious strategies and modern developments in the field, envisioning a future where starch-based nanomaterials play a transformative role in molecular nanomaterials, evolving biomedical sciences. The translation of these advancements into clinical applications holds the potential to revolutionize targeted drug delivery and expand therapeutic outcomes in the realm of precision medicine.

Evolution of Hybrid Hydrogels: Next-Generation Biomaterials for Drug Delivery and Tissue Engineering

Hydrogels, being hydrophilic polymer networks capable of absorbing and retaining aqueous fluids, hold significant promise in biomedical applications owing to their high water content, permeability, and structural similarity to the extracellular matrix. Recent chemical advancements have bolstered their versatility, facilitating the integration of the molecules guiding cellular activities and enabling their controlled activation under time constraints. However, conventional synthetic hydrogels suffer from inherent weaknesses such as heterogeneity and network imperfections, which adversely affect their mechanical properties, diffusion rates, and biological activity. In response to these challenges, hybrid hydrogels have emerged, aiming to enhance their strength, drug release efficiency, and therapeutic effectiveness. These hybrid hydrogels, featuring improved formulations, are tailored for controlled drug release and tissue regeneration across both soft and hard tissues. The scientific community has increasingly recognized the versatile characteristics of hybrid hydrogels, particularly in the biomedical sector. This comprehensive review delves into recent advancements in hybrid hydrogel systems, covering the diverse types, modification strategies, and the integration of nano/microstructures. The discussion includes innovative fabrication techniques such as click reactions, 3D printing, and photopatterning alongside the elucidation of the release mechanisms of bioactive molecules. By addressing challenges, the review underscores diverse biomedical applications and envisages a promising future for hybrid hydrogels across various domains in the biomedical field.

Photoinduced Electron Transfer-Based Glutathione-Sensing Theranostic Nanoprodrug with Self-Tracking and Real-Time Drug Release Monitoring for Cancer Treatment

The rapid development of nanomedicine has considerably advanced precision therapy for cancer treatment. Superior to traditional chemotherapy, emerging theranostic nanoprodrugs can effectively realize inherent self-tracking, targeted drug delivery, stimuli-triggered drug release, and reduced systemic toxicity of chemotherapeutic drugs. However, theranostic nanoprodrugs with real-time drug release monitoring have remained rare so far. In this work, we developed a new glutathione-responsive theranostic nanoprodrug with a high drug-loading content of 59.4 wt % and an average nanoscale size of 46 nm, consisting of the anticancer drug paclitaxel and a fluorescent imaging probe with a high fluorescence quantum yield, which are linked by a disulfide-based glutathione-sensitive self-immolating linker. The strong fluorescence emission of the fluorophore enables efficacious self-tracking and sensitive fluorescence "ON-OFF" glutathione sensing. Upon encountering high-level glutathione in cancer cells, the disulfide bond is cleaved, and the resulting linker halves spontaneously collapse into cyclic small molecules at the same pace, leading to the simultaneous release of the therapeutic drug and the fluorescence-OFF imaging probe. Thereby, the drug release process is efficiently monitored by the fluorescence change in the nanoprodrug. The nanoprodrugs exerted high cytotoxicity toward various cancer cells, especially for A549 and HEK-293 cells, in which the nanoprodrugs generated better therapeutic effects than free paclitaxel. Our work demonstrated a new modality of smart theranostic nanoprodrugs for precise cancer therapy.

Tumor Microenvironment-Responsive Drug Delivery Based on Polymeric Micelles for Precision Cancer Therapy: Strategies and Prospects

In clinical practice, drug therapy for cancer is still limited by its inefficiency and high toxicity. For precision therapy, various drug delivery systems, including polymeric micelles self-assembled from amphiphilic polymeric materials, have been developed to achieve tumor-targeting drug delivery. Considering the characteristics of the pathophysiological environment at the drug target site, the design, synthesis, or modification of environmentally responsive polymeric materials has become a crucial strategy for drug-targeted delivery. In comparison to the normal physiological environment, tumors possess a unique microenvironment, characterized by a low pH, high reactive oxygen species concentration, hypoxia, and distinct enzyme systems, providing various stimuli for the environmentally responsive design of polymeric micelles. Polymeric micelles with tumor microenvironment (TME)-responsive characteristics have shown significant improvement in precision therapy for cancer treatment. This review mainly outlines the most promising strategies available for exploiting the tumor microenvironment to construct internal stimulus-responsive drug delivery micelles that target tumors and achieve enhanced antitumor efficacy. In addition, the prospects of TME-responsive polymeric micelles for gene therapy and immunotherapy, the most popular current cancer treatments, are also discussed. TME-responsive drug delivery via polymeric micelles will be an efficient and robust approach for developing clinical cancer therapies in the future.

A multimodal therapy for infected diabetic wounds based on glucose-responsive nanocomposite-integrated microneedles

Diabetic wounds in a state of high glucose are refractory to treatment and healing, especially if they are infected with bacteria. Herein, a novel nanocomposite (CIP/GOx@ZIF-8) was synthesized by loading ciprofloxacin hydrochloride (CIP) and glucose oxidase (GOx) into zeolitic imidazole framework-8 (ZIF-8) that exhibited good glucose sensitivity and catalytic activity. The high glucose in diabetic wounds could be decomposed into hydrogen peroxide (H2O2) and gluconic acid via the catalysis of GOx, which further destroyed CIP/GOx@ZIF-8 to release Zn2+ and cargos. The combination of glucose starvation, Zn2+, H2O2 and CIP could elevate the antibacterial effect and reduce bacterial resistance. Subsequently, the nanocomposite was fabricated into dissolving microneedles (CIP/GOx@ZIF-8 MNs) using polyvinylpyrrolidone (PVP). The microneedles exhibited good mechanical strength, puncture performance, dissolving performance, glucose responsiveness, antibacterial performance and biocompatibility. For in vivo wound healing, CIP/GOx@ZIF-8 MNs with good biosafety facilitated neovascularization and collagen deposition as well as reduced inflammation, and the wounds were almost healed after treatment. This multimodal therapeutic strategy is created to provide a unique treatment for infected diabetic wounds.

Paclitaxel-loaded ROS-responsive nanoparticles for head and neck cancer therapy

High intracellular reactive oxygen species (ROS) level is characteristic of cancer cells and could act as a target for the efficient targeted drug delivery for cancer treatment. Consequently, biomaterials that react to excessive levels of ROS are essential for biomedical applications. In this study, a novel ROS-responsive polymer based on D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) and poly (β-thioester) (TPGS-PBTE) was synthesized for targeted delivery of the first-line antineoplastic drug, paclitaxel (PTX). The resultant TPGS-PBTE NPs showed good ROS-responsive capability in size change and drug release. Compared to PTX, PTX-loaded nanoparticles (PTX@TPGS-PBTE NPs) showed enhanced cytotoxicity and higher level of apoptosis toward squamous cell carcinoma (SCC-7) cells. Tumor-targeted delivery of the NPs was also observed, especially after being modified with a tumor-targeting peptide, cRGD. Enhanced tumor growth inhibition was also observed in head and neck cancer SCC-7 murine models. In summary, PTX@TPGS-PBTE NPs can achieve good therapeutic effects of PTX against head and neck cancer both in vitro and in vivo, especially when modified by cRGD for active targeting, which enriched the application of ROS responsive system utilized in the delivery of anticancer drugs.

Smart nanoparticles for cancer therapy

Smart nanoparticles, which can respond to biological cues or be guided by them, are emerging as a promising drug delivery platform for precise cancer treatment. The field of oncology, nanotechnology, and biomedicine has witnessed rapid progress, leading to innovative developments in smart nanoparticles for safer and more effective cancer therapy. In this review, we will highlight recent advancements in smart nanoparticles, including polymeric nanoparticles, dendrimers, micelles, liposomes, protein nanoparticles, cell membrane nanoparticles, mesoporous silica nanoparticles, gold nanoparticles, iron oxide nanoparticles, quantum dots, carbon nanotubes, black phosphorus, MOF nanoparticles, and others. We will focus on their classification, structures, synthesis, and intelligent features. These smart nanoparticles possess the ability to respond to various external and internal stimuli, such as enzymes, pH, temperature, optics, and magnetism, making them intelligent systems. Additionally, this review will explore the latest studies on tumor targeting by functionalizing the surfaces of smart nanoparticles with tumor-specific ligands like antibodies, peptides, transferrin, and folic acid. We will also summarize different types of drug delivery options, including small molecules, peptides, proteins, nucleic acids, and even living cells, for their potential use in cancer therapy. While the potential of smart nanoparticles is promising, we will also acknowledge the challenges and clinical prospects associated with their use. Finally, we will propose a blueprint that involves the use of artificial intelligence-powered nanoparticles in cancer treatment applications. By harnessing the potential of smart nanoparticles, this review aims to usher in a new era of precise and personalized cancer therapy, providing patients with individualized treatment options.

Advances in the stimuli-responsive mesoporous silica nanoparticles as drug delivery system nanotechnology for controlled release and cancer therapy

Mesoporous silica nanoparticles (MSN) have attracted widespread attention in the field of drug delivery and biomedicine due to their unique structure and physicochemical properties. However, MSN still have shortcomings, such as premature drug release, poorly controlled release ability and poor targeting. Therefore, in order to reduce the damage of anti-cancer drugs to normal cells, improve their utilization rate and realize their selective release in tumor cells, "gated" stimuli-responsive mesoporous silicon nanomaterials as antitumor drug delivery carriers have attracted widespread interest among researchers. The "gated" stimuli-responsive nanovalves drug delivery system can only be removed under certain specific stimuli, which makes the drug maintain "zero release" before reaching the lesion site and achieve drug accumulation in tumor cells, effectively reducing the toxic and side effects on normal cells or tissues, and greatly exerting the efficacy of anti-cancer drugs. Therefore, the construction of stimuli-responsive nano-drug delivery systems have great application potential and significance in cancer treatment and controlled release of anti-cancer drugs. This review article emphasizes the research progress of the "gated" stimuli-responsive MSN (e.g. pH, redox potential, enzyme, temperature and light) or controlled drug release and cancer treatment since 2019.

Recent advances in nanomedicine preparative methods and their therapeutic potential for colorectal cancer: a critical review

Colorectal cancer (CRC) is a prevalent malignancy that affects a large percentage of the global population. The conventional treatments for CRC have a number of limitations. Nanoparticles have emerged as a promising cancer treatment method due to their ability to directly target cancer cells and regulate drug release, thereby enhancing therapeutic efficacy and minimizing side effects. This compilation examines the use of nanoparticles as drug delivery systems for CRC treatment. Different nanomaterials can be used to administer anticancer drugs, including polymeric nanoparticles, gold nanoparticles, liposomes, and solid lipid nanoparticles. In addition, we discuss recent developments in nanoparticle preparation techniques, such as solvent evaporation, salting-out, ion gelation, and nanoprecipitation. These methods have demonstrated high efficacy in penetrating epithelial cells, a prerequisite for effective drug delivery. This article focuses on the various targeting mechanisms utilized by CRC-targeted nanoparticles and their recent advancements in this field. In addition, the review offers descriptive information regarding numerous nano-preparative procedures for colorectal cancer treatments. We also discuss the outlook for innovative therapeutic techniques in the management of CRC, including the potential application of nanoparticles for targeted drug delivery. The review concludes with a discussion of current nanotechnology patents and clinical studies used to target and diagnose CRC. The results of this investigation suggest that nanoparticles have great potential as a method of drug delivery for the treatment of colorectal cancer.

A mitochondria-targeting self-assembled carrier-free lonidamine nanodrug for redox-activated drug release to enhance cancer chemotherapy

Mitochondria play a vital role in maintaining cellular homeostasis. In recent years, studies have found that mitochondria have an important role in the occurrence and development of tumors, and targeting mitochondria has become a new strategy for tumor treatment. Lonidamine (LND), as a hexokinase inhibitor, can block the energy supply and destroy mitochondria. However, poor water solubility and low mitochondrial selectivity limit its clinical application. To overcome these obstacles, we report redox-activated self-assembled carrier-free nanoparticles (Cy-TK-LND NPs) based on a small molecule prodrug, in which photosensitizer IR780 (Cy) which targets mitochondria is conjugated to LND via a sensitive thioketal (TK) linker. Intracellular oxidative stress induced by laser radiation leads to the responsive cleavage of Cy-TK-LND NPs, facilitating the release of free LND into mitochondria. Subsequently, LND damages mitochondria, triggering the apoptosis pathway. The results show the effective killing effect of Cy-TK-LND NPs on cancer cells in vitro and in vivo. The IC50 value of irradiated Cy-TK-LND NPs is 5-fold lower than that of free LND. Moreover, tumor tissue section staining results demonstrate that irradiated Cy-TK-LND NPs induce necrosis and apoptosis of tumor cells, upregulate cytochrome C and pro-apoptotic Bax, and downregulate anti-apoptotic Bcl-2. Generally, Cy-TK-LND NPs exhibit efficient mitochondria-targeted delivery to improve the medicinal availability of LND. Accordingly, such a carrier-free prodrug-based nanomedicine holds promise as an effective cancer chemotherapy strategy.

Nanostructured steady-state nanocarriers for nutrients preservation and delivery

Food bioactives possess specific physiological benefits of preventing certain diet-related chronic diseases or maintain human health. However, the limitations of the bioactives are their poor stability, lower water solubility and unacceptable bioaccessibility. Structure damage or degradation is often found for the bioactives under certain environmental conditions like high temperature, strong light, extreme pH or high oxygen concentration during food processing, packaging, storage and absorption. Nanostructured steady-state nanocarriers have shown great potential in overcoming the drawbacks for food bioactives. Various delivery systems including solid form delivery system, liquid form delivery system and encapsulation technology have been developed. The embedded food nutrients can largely decrease the loss and degradation during food processing, packaging and storage. The design and application of stimulus and targeted delivery systems can improve the stability, bioavailability and efficacy of the food bioactives upon oral consumption due to enzymatic degradation in the gastrointestinal tract. The food nutrients encapsulated in the smart delivery system can be well protected against degradation during oral administration, thus improving the bioavailability and releazing controlled or targeted release for food nutrients. The encapsulated food bioactives show great potential in nutrition therapy for sub-health status and disease. Much effort is required to design and prepare more biocompatible nanostructured steady-state nanocarriers using food-grade protein or polysaccharides as wall materials, which can be used in food industry and maintain the human health.

Utilization of Functionalized Metal–Organic Framework Nanoparticle as Targeted Drug Delivery System for Cancer Therapy

Cancer is a multifaceted disease that results from the complex interaction between genetic and environmental factors. Cancer is a mortal disease with the biggest clinical, societal, and economic burden. Research on better methods of the detection, diagnosis, and treatment of cancer is crucial. Recent advancements in material science have led to the development of metal–organic frameworks, also known as MOFs. MOFs have recently been established as promising and adaptable delivery platforms and target vehicles for cancer therapy. These MOFs have been constructed in a fashion that offers them the capability of drug release that is stimuli-responsive. This feature has the potential to be exploited for cancer therapy that is externally led. This review presents an in-depth summary of the research that has been conducted to date in the field of MOF-based nanoplatforms for cancer therapeutics.

pH and GSH dual-responsive drug-controlled nanomicelles for breast cancer treatment

We developed a pH/glutathione (GSH) dual-responsive smart nano-drug delivery system to achieve targeted release of a chemotherapeutic drug at breast tumor site. Doxorubicin (DOX) was linked to polyethylene glycol (PEG) through cis-aconitic anhydride (CA) and disulfide bonds (SS) to obtain the PEG-SS-CA-DOX prodrug, which spontaneously assembled into nanomicelles with a particle size of 48 ± 0.45 nm. PEG-SS-CA-DOX micelles achieved an efficient and rapid release of DOX under dual stimulation by weak acidic pH and high GSH content of tumors, with the release amount reaching 88.0% within 48 h. Cellular uptake experiments demonstrated that PEG-SS-CA-DOX micelles could efficiently transport DOX into cells and rapidly release it in the tumor microenvironment. In addition,in vivoantitumor experiments showed that PEG-SS-CA-DOX had a high inhibition rate of 70% against 4T1 breast cancer cells along with good biosafety. In conclusion, dual-responsive smart nanomicelles can achieve tumor-targeted drug delivery and specific drug release, thus improving therapeutic efficacy of drugs.

Gold Nanoparticles as Drug Carriers: The Role of Silica and PEG as Surface Coatings in Optimizing Drug Loading

The use of gold nanoparticles as drug delivery systems has received increasing attention due to their unique properties, such as their high stability and biocompatibility. However, gold nanoparticles have a high affinity for proteins, which can result in their rapid clearance from the body and limited drug loading capabilities. To address these limitations, we coated the gold nanoparticles with silica and PEG, which are known to improve the stability of nanoparticles. The synthesis of the nanoparticles was carried out using a reduction method. The nanoparticles' size, morphology, and drug loading capacity were also studied. The SEM images showed a spherical and homogeneous morphology; they also showed that the coatings increased the average size of the nanoparticles. The results of this study provide insight into the potential of gold nanoparticles coated with silica and PEG as drug delivery systems. We used ibuprofen as a model drug and found that the highest drug load occurred in PEG-coated nanoparticles and then in silica-coated nanoparticles, while the uncoated nanoparticles had a lower drug loading capacity. The coatings were found to significantly improve the stability and drug load properties of the nanoparticles, making them promising candidates for further development as targeted and controlled release drug delivery systems.

Responsive Nanostructure for Targeted Drug Delivery

Currently, intelligent, responsive biomaterials have been widely explored, considering the fact that responsive biomaterials provide controlled and predictable results in various biomedical systems. Responsive nanostructures undergo reversible or irreversible changes in the presence of a stimulus, and that stimuli can be temperature, a magnetic field, ultrasound, pH, humidity, pressure, light, electric field, etc. Different types of stimuli being used in drug delivery shall be explained here. Recent research progress in the design, development and applications of biomaterials comprising responsive nanostructures is also described here. More emphasis will be given on the various nanostructures explored for the smart stimuli responsive drug delivery at the target site such as wound healing, cancer therapy, inflammation, and pain management in order to achieve the improved efficacy and sustainability with the lowest side effects. However, it is still a big challenge to develop well-defined responsive nanostructures with ordered output; thus, challenges faced during the design and development of these nanostructures shall also be included in this article. Clinical perspectives and applicability of the responsive nanostructures in the targeted drug delivery shall be discussed here.

Naphthyl-Poly(S-((2-carboxyethyl)thio)-l-cysteine) Peptide Amphiphiles with Different Degrees of Polymerization: Synthesis, Self-Assembly, pH/Reduction-Triggered Drug Release, and Cytotoxicity

Four peptide amphiphiles (PA1-4) with different degrees of polymerization (DP = 40, 15, 10, and 6) were synthesized by Fuchs-Farthing and ring-opening polymerization followed by post-polymerization modification, as fully characterized by ¹H NMR, FT-IR, gel permeation chromatography, and circular dichroism (CD) spectroscopy. It was found that PAs could self-assemble to form regular spherical micelles in low-concentration (about 1 mg/mL) aqueous solution, which had different contents of secondary structures and mainly adopted random coil conformations. The water solubility of PAs increases with the increase of DP, the polypeptide chain stretches randomly in water, the β-sheets decrease, and the random coil conformations dominate. When the pH of PA solution decreases or increases, intramolecular hydrogen bonds break, and molecular chains stretch, leading to a decrease of α-helix, turn conformations, and an increase of β-sheets. Meanwhile, the particle size of micelles increases. At around 0.4 mg/mL, the hemolysis ability of PA2 is negligible at pH 7.4 and 6.5 and about 33% at pH 5.5. Cisplatin (CDDP) was linked to micelles by coordination bonds to explore their potential as drug carriers, exhibiting controlled pH and reduction in dual drug release effects. MTT assay showed that the HeLa cell viability was 78% when cultured in the 13.5 μg/mL PA2 blank micelles for 2 days, while the cell viability was 60% in the CDDP-loaded micelles. Furthermore, a high concentration of PA2 (about 100 mg/mL) could self-assemble into a fibrous hydrogel at pH 5.5, which self-healed 2 h after incision and self-degraded 71% within 14 days. The CDDP-loaded fiber hydrogel exhibited a sustained release effect similar to the CDDP-loaded micelles. The cytotoxicity of CDDP-loaded fibers at 48 h was detected to be the same as that of the same amount of CDDP, and the cell viability was 7%. Therefore, we provide a new strategy for the synthesis of amphiphilic peptides with potential applications in nano-drug carriers and cancer therapy.

Use of stimulatory responsive soft nanoparticles for intracellular drug delivery

Drug delivery has made tremendous advances in the last decade. Targeted therapies are increasingly common, with intracellular delivery highly impactful and sought after. Intracellular drug delivery systems have limitations due to imprecise and non-targeted release profiles. One way this can be addressed is through using stimuli-responsive soft nanoparticles, which contain materials with an organic backbone such as lipids and polymers. The choice of biomaterial is essential for soft nanoparticles to be responsive to internal or external stimuli. The nanoparticle must retain its integrity and payload in non-targeted physiological conditions while responding to particular intracellular environments where payload release is desired. Multiple internal and external factors could stimulate the intracellular release of drugs from nanoparticles. Internal stimuli include pH, oxidation, and enzymes, while external stimuli include ultrasound, light, electricity, and magnetic fields. Stimulatory responsive soft nanoparticulate systems specifically utilized to modulate intracellular delivery of drugs are explored in this review.

Promising Role of Polylactic Acid as an Ingenious Biomaterial in Scaffolds, Drug Delivery, Tissue Engineering, and Medical Implants: Research Developments, and Prospective Applications

In the present scenario, the research is now being focused on the naturally occurring polymers that can gradually replace the existing synthetic polymers for the development of bio composites having applications in medical surgeries and human implants. With promising mechanical properties and bio compatibility with human tissues, poly lactic acid (PLA) is now being viewed as a future bio material. In order to examine the applicability of PLA in human implants, the current article sheds light on the synthesis of PLA and its various copolymers used to alter its physical and mechanical properties. In the latter half, various processes used for the fabrication of biomaterials are discussed in detail. Finally, biomaterials that are currently in use in the field of biomedical (Scaffolding, drug delivery, tissue engineering, medical implants, derma, cosmetics, medical surgeries, and human implants) are represented with respective advantages in the sphere of biomaterials.

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.

Role of Iron Oxide (Fe2O3) Nanocomposites in Advanced Biomedical Applications: A State-of-the-Art Review

Nanomaterials have demonstrated a wide range of applications and recently, novel biomedical studies are devoted to improving the functionality and effectivity of traditional and unmodified systems, either drug carriers and common scaffolds for tissue engineering or advanced hydrogels for wound healing purposes. In this regard, metal oxide nanoparticles show great potential as versatile tools in biomedical science. In particular, iron oxide nanoparticles with different shape and sizes hold outstanding physiochemical characteristics, such as high specific area and porous structure that make them idoneous nanomaterials to be used in diverse aspects of medicine and biological systems. Moreover, due to the high thermal stability and mechanical strength of Fe₂O₃, they have been combined with several polymers and employed for various nano-treatments for specific human diseases. This review is focused on summarizing the applications of Fe₂O₃-based nanocomposites in the biomedical field, including nanocarriers for drug delivery, tissue engineering, and wound healing. Additionally, their structure, magnetic properties, biocompatibility, and toxicity will be discussed.

Recent advances in redox-responsive nanoparticles for combined cancer therapy

The combination of multiple therapeutic modalities has attracted increasing attention as it can achieve better therapeutic effects through different treatment mechanisms. However, traditional small molecule agents are non-specific to the tumor tissue, which leads to off-target toxic effects for healthy tissues. To solve this problem, a number of stimuli-responsive nanoscale drug-delivery systems have been developed. Among these stimuli, a high concentration of reactive oxygen species (ROS) and glutathione (GSH) are characteristic of the tumor microenvironment (TME), which can distinguish it from normal tissue. In this review, we summarize the redox-responsive nanoparticles (NPs) reported in the past three years classified by different functional groups, including GSH-responsive disulfide, ditelluride, and multivalent metal ions, ROS-responsive thioketal, arylboronic ester, aminoacrylate, and bilirubin as well as GSH/ROS dual-responsive diselenide and dicarbonyl thioethers. The prospects and challenges of redox-responsive NPs are also discussed.

Stimuli-responsive nanoassemblies for targeted delivery against tumor and its microenvironment

Despite the emergence of various cancer treatments, such as surgery, chemotherapy, radiotherapy, and immunotherapy, their use remains restricted owing to their limited tumor elimination efficacy and side effects. The use of nanoassemblies as delivery systems in nanomedicine for tumor diagnosis and therapy is flourishing. These nanoassemblies can be designed to have various shapes, sizes, and surface charges to meet the requirements of different applications. It is crucial for nanoassemblies to have enhanced delivery of payloads while inducing minimal to no toxicity to healthy tissues. In this review, stimuli-responsive nanoassemblies capable of combating the tumor microenvironment (TME) are discussed. First, various TME characteristics, such as hypoxia, oxidoreduction, adenosine triphosphate (ATP) elevation, and acidic TME, are described. Subsequently, the unique characteristics of the vascular and stromal TME are differentiated, and multiple barriers that have to be overcome are discussed. Furthermore, strategies to overcome these barriers for successful drug delivery to the targeted site are reviewed and summarized. In conclusion, the possible challenges and prospects of using these nanoassemblies for tumor-targeted delivery are discussed. This review aims at inspiring researchers to develop stimuli-responsive nanoassemblies for tumor-targeted delivery for clinical applications.

Stimuli-Responsive Miktoarm Polymer-Based Formulations for Fisetin Delivery and Regulatory Effects in Hyperactive Human Microglia

Branched star polymers offer exciting opportunities in enhancing the efficacy of nanocarriers in delivering biologically active lipophilic agents. We demonstrate that the star polymeric architecture can be leveraged to yield soft nanoparticles of vesicular morphology with precisely located stimuli-sensitive chemical entities. Amphiphilic stars of AB₂ (A = PEG, B = PCL) composition with/without oxidative stress or reduction responsive units at the core junction of A and B arms, are constructed using synthetic articulation. Fisetin, a natural flavonoid with remarkable anti-inflammatory and antioxidant properties, but of limited clinical value due to its poor aqueous solubility, was physically encapsulated into miktoarm star-derived aqueous polymersomes. We evaluated polymersomes and fisetin separately, and in combination, in human microglia (HMC3), to show if (i) polymersomes are toxic; (ii) fisetin reduces the abundance of reactive oxygen species (ROS); and (iii) fisetin modulates the activation of ERK1/2. These signaling molecules and pathways are implicated in inflammatory processes and cell survival. Fisetin, both incorporated and non-incorporated into polymersomes, reduced ROS and ERK1/2 phosphorylation in lipopolysaccharide-treated human microglia, normalizing excessive oxidative stress and ERK-mediated signaling. This article is protected by copyright. All rights reserved.

Release of bioactive compounds from delivery systems by stimuli-responsive approaches; triggering factors, mechanisms, and applications

Recent advances in emerging nanocarriers and stimuli-responsive (SR) delivery systems have brought about a revolution in the food and pharmaceutical industries. SR carriers are able to release the encapsulated bioactive compounds (bioactives) upon an external trigger. The potential of releasing the loaded bioactives in site-specific is of great importance for the pharmaceutical industry and medicine that can deliver the cargo in an appropriate condition. For the food industry, release of encapsulated bioactives is considerably important in processing or storage of food products and can be used in their formulation or packaging. There are various stimuli to control the favorite release of bioactives. In this review, we will shed light on the effect of different stimuli such as temperature, humidity, pH, light, enzymatic hydrolysis, redox, and also multiple stimuli on the release of encapsulated cargo and their potential applications in the food and pharmaceutical industries. An overview of cargo release mechanisms is also discussed. Furthermore, various alternatives to manipulate the controlled release of bioactives from carriers and the perspective of more progress in these SR carriers are highlighted.

Application of curcumin nanoformulations in Alzheimer's disease: prevention, diagnosis and treatment

Objectives: Alzheimer's disease (AD) is a serious neurodegenerative disease. Although many therapeutic strategies have been studied, their clinical applications are immature. Moreover, these methods can only alleviate symptoms rather than cure it, posing a challenge to brain health in older adults worldwide. Curcumin (CUR) is a very promising natural compound for nerve protection and treatment. It can prevent and treat AD, and on the other hand, its fluorescence properties can be used in the diagnosis of AD. However, CUR is characterized by very low water solubility, fluid instability, rapid metabolism, low bioavailability and difficulty in penetrating the biological barriers, which limit its application. Nanocarriers are a potential material to improve the biocompatibility of CUR and its ability to cross biological barriers. Therefore, delivering CUR by nanocarriers is an effective method to achieve better efficacy. Methods: In this review, the preventive, therapeutic and diagnostic effects of CUR nanoformulations on AD, as well as various patents, clinical trials and experimental research progress in this field are discussed. The aim is to provide detailed reference and practical suggestions for future research. Results: CUR has a variety of pharmacological activities in the prevention and treatment of AD, and its nanoformulation can effectively improve solubility, bioavailability and the ability to penetrate the blood-brain barrier. Significant benefits have been observed in the current study. Discussion: CUR formulations have a good prospect in the prevention, diagnosis and treatment of AD, but the safety and principle of its administration need more detailed study in the future.

Liposome-Loaded Targeted Theranostic Fluorescent Nano-Probes for Diagnosis and Treatment of Cervix Carcinoma

Near-infrared fluorescence imaging, with its high sensitivity, non-invasiveness, and superior real-time feedback properties, has become a powerful skill for accurate diagnosis in the clinic. Nanoparticle-assisted chemotherapy is an effective cure for cancer. Specifically, the combination of near-infrared fluorescence imaging with chemotherapy represents a promising method for precise diagnosis and treatment of cervical cancer. To realize this approach, it is necessary to design and synthesize therapeutic nano-probes with detection abilities. In this work, an organic NIRF emissive heptamethine cyanine dye, IR783, was utilized and encapsulated in biocompatible drug-carrier liposomes). Then, the anticancer drug doxorubicin was loaded, to form LP-IR783-DOX nanoparticles. The LP-IR783-DOX nanoparticles had spherical shapes and were smoothly dispersed in aqueous solutions. Favorable absorption (a peak of 800 nm) and fluorescence (a peak of 896 nm) features were obtained from LP-IR783-DOX nanoparticles in the near-infrared region. Moreover, the specific detection abilities of nanoparticles were confirmed in different cell lines, and nanoparticles exhibited strong detection abilities in human cervix carcinoma cells in particular. To analyze the chemotherapeutic properties of LP-IR783-DOX nanoparticles, live HeLa cells were studied in detail, and the application of these NPs resulted in a chemotherapeutic efficiency of 56.75% based on fluorescein isothiocyanate staining and flow cytometry. The results indicate that nanoparticles have great potential for theranostic application of fluorescence imaging and chemotherapy in cases of cervical cancer.

How Advancing are Mesoporous Silica Nanoparticles? A Comprehensive Review of the Literature

The application of mesoporous silica nanoparticles (MSNs) is ubiquitous in various sciences. MSNs possess unique features, including the diversity in manufacturing by different synthesis methods and from different sources, structure controllability, pore design capabilities, pore size tunability, nanoparticle size distribution adjustment, and the ability to create diverse functional groups on their surface. These characteristics have led to various types of MSNs as a unique system for drug delivery. In this review, first, the synthesis of MSNs by different methods via using different sources were studied. Then, the parameters affecting their physicochemical properties and functionalization have been discussed. Finally, the last decade’s novel strategies, including surface functionalization, drug delivery, and cancer treatment, based on the MSNs in drug delivery and cancer therapy have been addressed.

Theranostic applications of stimulus-responsive systems based on Fe2O3

According to the interaction of nanoparticles with biological systems, enthusiasm for nanotechnology in biomedical applications has been developed in the past decades. Fe2O3 nanoparticles, as the most stable iron oxide, have special merits that make them useful widely for detecting diseases, therapy, drug delivery, and monitoring the therapeutic process. This review presents the fabrication methods of Fe2O3-based materials and their photocatalytic and magnetic properties. Then, we highlight the application of Fe2O3-based nanoparticles in diagnosis and imaging, different therapy methods, and finally, stimulus-responsive systems, such as pH-responsive, magnetic-responsive, redox-responsive, and enzyme-responsive, with an emphasis on cancer treatment. In addition, the potential of Fe2O3 to combine diagnosis and therapy within a single particle called theranostic agent will be discussed.

Synergic Antitumor Effect of Photodynamic Therapy and Chemotherapy Mediated by Nano Drug Delivery Systems

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various benefits from using these nanocarriers including enhanced water solubility, stability, longer circulation times, and higher accumulation of therapeutic agents/photosensitizers at tumor sites. This review also describes novel approaches from different research groups that utilize various targeting strategies to increase treatment efficacy through simultaneous photodynamic therapy and chemotherapy.

Dimension switchable auto-fluorescent peptide-based 1D and 2D nano-assemblies and their self-influence on intracellular fate and drug delivery

The production of dynamic, environment-responsive shape-tunable biomaterials marks a significant step forward in the construction of synthetic materials that can easily rival their natural counterparts. Significant progress has been made in the self-assembly of bio-materials. However, the self-assembly of a peptide into morphologically distinct auto-fluorescent nanostructures, without the incorporation of any external moiety is still in its infancy. Hence, in this study, we have developed peptide-based self-assembled auto-fluorescent nanostructures that can shuttle between 1D and 2D morphologies. Different morphological nanostructures are well known to have varied cellular internalization efficiencies. Taking advantage of our morphologically different particles emanating from the same peptide monomer, we further explored the intracellular fate of our nanostructures. We observed that the nanostructures' cellular internalization is a complex process that gets influenced by particle morphology and this might further affect their intracellular drug delivery potential. Overall, this study provides initial cues for the preparation of environment-responsive shape-shifting peptide-nano assemblies. Efforts have also been made to understand their shape driven cellular uptake behaviour, along with establishing them as nanocarriers for the cellular delivery of therapeutic molecules.

Vitamin-H Channeled Self-Therapeutic P-gp Inhibitor Curcumin-Derived Nanomicelles for Targeting the Tumor Milieu by pH- and Enzyme-Triggered Hierarchical Disassembly

An effective nanocarrier-mediated drug delivery to cancer cells primarily faces limitations like the presence of successive drug delivery barriers, insufficient circulation time, drug leakage, and decreased tumor penetration capacity. With the aim of addressing this paradox, a self-therapeutic, curcumin-derived copolymer was synthesized by conjugation with PEGylated biotin via enzyme- and acid-labile ester and acetal linkages. This copolymer is a prodrug of curcumin and self-assembles into ∼150-200 nm-sized nanomicelles; it is capable of encapsulating doxorubicin (DOX) and hence can be designated as self-therapeutic. pH- and enzyme-responsive linkages in the polymer skeleton assist in its hierarchical disassembly only in the tumor microenvironment. Further, the conjugation of biotin and poly(ethylene glycol) (PEG) imparts features of tumor specificity and improved circulation times to the nanocarrier. The dynamic light scattering (DLS) analysis supports this claim and demonstrates rapid swelling and disruption of micelles under acidic pH. UV-vis spectroscopy provided evidence of an accelerated acetal degradation at pH 4.0 and 5.0. The in vitro release studies revealed a controlled release of DOX under acidic conditions and curcumin release in response to the enzyme. The value of the combination index calculated on HepG2 cells was found to be <1, and hence, the drug pair curcumin and DOX acts synergistically for tumor regression. To prove the efficiency of acid-labile linkages and the prodrug strategy for effective cancer therapy, curcumin-derived polymers devoid of sensitive linkages were also prepared. The prodrug stimuli-responsive nanomicelles showed enhanced cell cytotoxicity and tumor penetration capability on HepG2 cells as well as drug-resistant MCF-7 cell lines and no effect on normal NIH/3T3 fibroblasts as compared to the nonresponsive micelles. The results were also supported by in vivo evidence on a hepatocellular carcinoma (HCC)-induced nude mice model. An evident decrease in MMP-2, MMP-9, and α-fetoprotein (AFP), the biomarkers specific to tumor progression, was observed along with metastasis upon treatment with the drug-loaded dual-responsive nanomicelles. These observations corroborated with the SGOT and SGPT data as well as the histoarchitecture of the liver tissue in mice.

Engineered Aptamer-Organic Amphiphile Self-Assemblies for Biomedical Applications: Progress and Challenges

Currently, nucleic acid aptamers are exploited as robust targeting ligands in the biomedical field, due to their specific molecular recognition, little immunogenicity, low cost, ect. Thanks to the facile chemical modification and high hydrophilicity, aptamers can be site-specifically linked with hydrophobic moieties to prepare aptamer-organic amphiphiles (AOAs), which spontaneously assemble into aptamer-organic amphiphile self-assemblies (AOASs). These polyvalent self-assemblies feature with enhanced target-binding ability, increased resistance to nuclease, and efficient cargo-loading, making them powerful platforms for bioapplications, including targeted drug delivery, cell-based cancer therapy, biosensing, and bioimaging. Besides, the morphology of AOASs can be elaborately manipulated for smarter biomedical functions, by regulating the hydrophilicity/hydrophobicity ratio of AOAs. Benefiting from the boom in DNA synthesis technology and nanotechnology, various types of AOASs, including aptamer-polymer amphiphile self-assemblies, aptamer-lipid amphiphile self-assemblies, aptamer-cell self-assemblies, ect, have been constructed with great biomedical potential. Particularly, stimuli-responsive AOASs with transformable structure can realize site-specific drug release, enhanced tumor penetration, and specific target molecule detection. Herein, the general synthesis methods of oligonucleotide-organic amphiphiles are firstly summarized. Then recent progress in different types of AOASs for bioapplications and strategies for morphology control are systematically reviewed. The present challenges and future perspectives of this field are also discussed.

Advanced Nanoengineering Approach for Target-Specific, Spatiotemporal, and Ratiometric Delivery of Gemcitabine-Cisplatin Combination for Improved Therapeutic Outcome in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an intractable malignancy with a dismal survival rate. Recent combination therapies have had a major impact on the improvement of PDAC prognosis. Nevertheless, clinically used combination regimens such as FOLFIRINOX and gemcitabine (Gem)/nab-paclitaxel still face major challenges due to lack of the safe and ratiometric delivery of multiple drugs. Here, a rationally designed mesoporous silica nanoparticle (MSN)-based platform is reported for the target-specific, spatiotemporal, ratiometric, and safe co-delivery of Gem and cisplatin (cisPt). It is shown that systemic administration of the nanoparticles results in synergistic therapeutic outcome in a syngeneic and clinically relevant genetically engineered PDAC mouse model that has rarely been used for the therapeutic evaluation of nanomedicine. This synergism is associated with a strategic engineering approach, in which nanoparticles provide redox-responsive controlled delivery and in situ differential release of Gem/cisPt drugs with the goal of overcoming resistance to Pt-based drugs. The platform is also rendered with additional tumor-specificity via a novel tumor-associated mucin1 (tMUC1)-specific antibody, TAB004. Overall, the platform suppresses tumor growth and eliminates the off-target toxicities of a highly toxic chemotherapy combination.

Small-Molecule Prodrug Nanoassemblies: An Emerging Nanoplatform for Anticancer Drug Delivery

The antitumor efficiency and clinical translation of traditional nanomedicines is mainly restricted by low drug loading, complex preparation technology, and potential toxicity caused by the overused carrier materials. In recent decades, small-molecule prodrug nanoassemblies (SMP-NAs), which are formed by the self-assembly of prodrugs themselves, have been widely investigated with distinct advantages of ultrahigh drug-loading and negligible excipients-trigged adverse reaction. Benefited from the simple preparation process, SMP-NAs are widely used for chemotherapy, phototherapy, immunotherapy, and tumor diagnosis. In addition, combination therapy based on the accurate co-delivery behavior of SMP-NAs can effectively address the challenges of tumor heterogeneity and multidrug resistance. Recent trends in SMP-NAs are outlined, and the corresponding self-assembly mechanisms are discussed in detail. Besides, the smart stimuli-responsive SMP-NAs and the combination therapy based on SMP-NAs are summarized, with special emphasis on the structure-function relationships. Finally, the outlooks and potential challenges of SMP-NAs in cancer therapy are highlighted.

Bifunctional lipids in tumor vaccines: An outstanding delivery carrier and promising immune stimulator

Cancer is still a major threat for human life, and the cancer immunotherapy can be more optimized to prolong life. However, the effect of immunotherapy is not encouraging. In order to achieve outstanding immune effect, it is necessary to strengthen antigens uptake of antigen presenting cells. Adjuvants were added to vaccines to achieve this purpose, which could be divided into two types: as an immunostimulatory molecule, the innate immunities of the body were triggered; or as a delivery carrier, and antigens were cross-delivery through the "cytoplasmic pathway" and released at a specific location. This paper reviewed the relevant research status of tumor vaccine immune adjuvants in recent years. Among the review, the function, combination strategies and derivatives of lipid A were discussed in detail. In addition, some suggestions on the existing problems and research direction of lipids as tumor vaccine adjuvants were put forward.

Redox-responsive glycosylated combretastatin A-4 derivative as novel tubulin polymerization inhibitor for glioma and drug delivery

Combretastatin A-4 (CA4), a tubulin inhibitor, binds to the colchicine site of tubulin, inhibits tubulin polymerization, and leads to the apoptosis of tumor cells. However, the poor hydrophilicity and blood-brain barrier (BBB) penetration ability of CA4 hampers its application in the treatment of glioma. In this study, a novel combretastatin A-4 derivative (CA4D) was designed and developed, which was further conjugated with glucose via disulfide-bond-bridged (CA4D-SS-Glu) to enhance the BBB penetration capacity. The obtained CA4D-SS-Glu conjugate displayed a suitable water partition coefficient and the superior ability across BBB in vitro and in vivo. In addition, the CA4D-SS-Glu exhibited rapid redox-responsive drug release in the presence of glutathione, enhanced in vitro cytotoxicity, and cell apoptosis. Our data further confirmed that CA4D-SS-Glu inhibited proliferation, and restrained migration via affecting microtubule stabilization. Additionally, the conjugate also showed the highest antiproliferative and antitumor action on glioma in vivo as compared to CA4D and CA4. Taken together, the novel CA4D-SS-Glu conjugate possess improved physicochemical property and BBB penetration ability, reduction triggered release of CA4D, and efficient antiproliferative activity. These results provided a novel and effective entry to the treatment of glioma.

Nano-Drug Design Based on the Physiological Properties of Glutathione

Glutathione (GSH) is involved in and regulates important physiological functions of the body as an essential antioxidant. GSH plays an important role in anti-oxidation, detoxification, anti-aging, enhancing immunity and anti-tumor activity. Herein, based on the physiological properties of GSH in different diseases, mainly including the strong reducibility of GSH, high GSH content in tumor cells, and the NADPH depletion when GSSH is reduced to GSH, we extensively report the design principles, effect, and potential problems of various nano-drugs in diabetes, cancer, nervous system diseases, fluorescent probes, imaging, and food. These studies make full use of the physiological and pathological value of GSH and develop excellent design methods of nano-drugs related to GSH, which shows important scientific significance and prominent application value for the related diseases research that GSH participates in or responds to.

Potential therapies and diagnosis based on Golgi-targeted nano drug delivery systems

With the rapid development of nanotechnology, organelle-targeted nano drug delivery systems (NDDSs) have emerged as a potential method which can transport drugs specifically to the subcellular compartments like nucleus, mitochondrion, lysosome, endoplasmic reticulum (ER) and Golgi apparatus (GA). GA not only plays a key role in receiving, modifying, packaging and transporting proteins and lipids, but also contributes to a set of cellular processes. Golgi-targeted NDDSs can alter the morphology of GA and will become a promising strategy with high specificity, low-dose administration and decreased occurrence of side effects. In this review, Golgi-targeted NDDSs and their applications in disease therapies and diagnosis such as cancer, metastasis, fibrosis and neurological diseases are introduced. Meanwhile, modifications of NDDSs to achieve targeting strategies, Golgi-disturbing agents to change the morphology of GA, special endocytosis to achieve endosomal/lysosomal escape strategies are also involved.

Recent developments in selenium-containing polymeric micelles: prospective stimuli, drug-release behaviors, and intrinsic anticancer activity

Selenium is capable of forming a dynamic covalent bond with itself and other elements and can undergo metathesis and regeneration reactions under optimum conditions. Its dynamic nature endows selenium-containing polymers with striking sensitivity towards some environmental alterations. In the past decade, several selenium-containing polymers were synthesized and used for the preparation of oxidation-, reduction-, and radiation-responsive nanocarriers. Recently, thioredoxin reductase, sonication, and osmotic pressure triggered the cleavage of Se-Se bonds and swelling or disassembly of nanostructures. Moreover, some selenium-containing nanocarriers form oxidation products such as seleninic acids and acrylates with inherent anticancer activities. Thus, selenium-containing polymers hold promise for the fabrication of ultrasensitive and multifunctional nanocarriers of radiotherapeutic, chemotherapeutic, and immunotherapeutic significance. Herein, we discuss the most recent developments in selenium-containing polymeric micelles in light of their architecture, multiple stimuli-responsive properties, emerging immunomodulatory activities, and future perspectives in the delivery and controlled release of anticancer agents.

Protease-triggered bioresponsive drug delivery for the targeted theranostics of malignancy

Proteases have a fundamental role in maintaining physiological homeostasis, but their dysregulation results in severe activity imbalance and pathological conditions, including cancer onset, progression, invasion, and metastasis. This striking importance plus superior biological recognition and catalytic performance of proteases, combining with the excellent physicochemical characteristics of nanomaterials, results in enzyme-activated nano-drug delivery systems (nanoDDS) that perform theranostic functions in highly specific response to the tumor phenotype stimulus. In the tutorial review, the key advances of protease-responsive nanoDDS in the specific diagnosis and targeted treatment for malignancies are emphatically classified according to the effector biomolecule types, on the premise of summarizing the structure and function of each protease. Subsequently, the incomplete matching and recognition between enzyme and substrate, structural design complexity, volume production, and toxicological issues related to the nanocomposites are highlighted to clarify the direction of efforts in nanotheranostics. This will facilitate the promotion of nanotechnology in the management of malignant tumors.