Endogenous and Exogenous Stimuli-Responsive Drug Delivery Systems for Programmed Site-Specific Release

Treatment avenues for age-related macular degeneration: Breakthroughs and bottlenecks

Age-related macular degeneration (AMD) is a significant factor contributing to serious vision loss in adults above 50. The presence of posterior segment barriers serves as chief roadblocks in the delivery of drugs to treat AMD. The conventional treatment strategies use is limited due to its off-targeted distribution in the eye, shorter drug residence, poor penetration and bioavailability, fatal side effects, etc. The above-mentioned downside necessitates drug delivery using some cutting-edge technology including diverse nanoparticulate systems and microneedles (MNs) which provide the best therapeutic delivery alternative to treat AMD efficiently. Furthermore, cutting-edge treatment modalities including gene therapy and stem cell therapy can control AMD effectively by reducing the boundaries of conventional therapies with a single dose. This review discusses AMD overview, conventional therapies for AMD and their restrictions, repurposed therapeutics and their anti-AMD activity through different mechanisms, and diverse barriers in drug delivery for AMD. Various nanoparticulate-based approaches including polymeric NPs, lipidic NPs, exosomes, active targeted NPs, stimuli-sensitive NPs, cell membrane-coated NPs, inorganic NPs, and MNs are explained. Gene therapy, stem cell therapy, and therapies in clinical trials to treat AMD are also discussed. Further, bottlenecks of cutting-edge (nanoparticulate) technology-based drug delivery are briefed. In a nutshell, cutting-edge technology-based therapies can be an effective way to treat AMD.

Designing Dual-Responsive Drug Delivery Systems: The Role of Phase Change Materials and Metal-Organic Frameworks

Stimuli-responsive drug delivery systems (DDSs) offer precise control over drug release, enhancing therapeutic efficacy and minimizing side effects. This review focuses on DDSs that leverage the unique capabilities of phase change materials (PCMs) and metal-organic frameworks (MOFs) to achieve controlled drug release in response to pH and temperature changes. Specifically, this review highlights the use of a combination of lauric and stearic acids as PCMs that melt slightly above body temperature, providing a thermally responsive mechanism for drug release. Additionally, this review delves into the properties of zeolitic imidazolate framework-8 (ZIF-8), a stable MOF under physiological conditions that decomposes in acidic environments, thus offering pH-sensitive drug release capabilities. The integration of these materials enables the fabrication of complex structures that encapsulate drugs within ZIF-8 or are enveloped by PCM layers, ensuring that drug release is tightly controlled by either temperature or pH levels, or both. This review provides comprehensive insights into the core design principles, material selections, and potential biomedical applications of dual-stimuli responsive DDSs, highlighting the future directions and challenges in this innovative field.

Nano-based drug delivery systems in hepatocellular carcinoma

The high recurrence rate of hepatocellular carcinoma (HCC) and poor prognosis after medical treatment reflects the necessity to improve the current chemotherapy protocols, particularly drug delivery methods. Development of targeted and efficient drug delivery systems (DDSs), in all active, passive and stimuli-responsive forms for selective delivery of therapeutic drugs to the tumour site has been extended to improve efficacy and reduce the severe side effects. Recent advances in nanotechnology offer promising breakthroughs in the diagnosis, treatment and monitoring of cancer cells. In this review, the specific design of DDSs based on the different nano-particles and their surface engineering is discussed. In addition, the innovative clinical studies in which nano-based DDS was used in the treatment of HCC were highlighted.

Stimuli-sensitive polymer prodrug nanocarriers by reversible-deactivation radical polymerization

Polymer prodrugs are based on the covalent linkage of therapeutic molecules to a polymer structure which avoids the problems and limitations commonly encountered with traditional drug-loaded nanocarriers in which drugs are just physically entrapped (e.g., burst release, poor drug loadings). In the past few years, reversible-deactivation radical polymerization (RDRP) techniques have been extensively used to design tailor-made polymer prodrug nanocarriers. This synthesis strategy has received a lot of attention due to the possibility of fine tuning their structural parameters (e.g., polymer nature and macromolecular characteristics, linker nature, physico-chemical properties, functionalization, etc.), to achieve optimized drug delivery and therapeutic efficacy. In particular, adjusting the nature of the drug-polymer linker has enabled the easy synthesis of stimuli-responsive polymer prodrugs for efficient spatiotemporal drug release. In this context, this review article will give an overview of the different stimuli-sensitive polymer prodrug structures designed by RDRP techniques, with a strong focus on the synthesis strategies, the macromolecular architectures and in particular the drug-polymer linker, which governs the drug release kinetics and eventually the therapeutic effect. Their biological evaluations will also be discussed.

MOFs for next-generation cancer therapeutics through a biophysical approach-a review

Metal-organic frameworks (MOFs) have emerged as promising nanocarriers for cancer treatment due to their unique properties. Featuring high porosity, extensive surface area, chemical stability, and good biocompatibility, MOFs are ideal for efficient drug delivery, targeted therapy, and controlled release. They can be designed to target specific cellular organelles to disrupt metabolic processes in cancer cells. Additionally, functionalization with enzymes mimics their catalytic activity, enhancing photodynamic therapy and overcoming apoptosis resistance in cancer cells. The controllable and regular structure of MOFs, along with their tumor microenvironment responsiveness, make them promising nanocarriers for anticancer drugs. These carriers can effectively deliver a wide range of drugs with improved bioavailability, controlled release rate, and targeted delivery efficiency compared to alternatives. In this article, we review both experimental and computational studies focusing on the interaction between MOFs and drug, explicating the release mechanisms and stability in physiological conditions. Notably, we explore the relationship between MOF structure and its ability to damage cancer cells, elucidating why MOFs are excellent candidates for bio-applicability. By understanding the problem and exploring potential solutions, this review provides insights into the future directions for harnessing the full potential of MOFs, ultimately leading to improved therapeutic outcomes in cancer treatment.

Nano-Proteolysis Targeting Chimeras (Nano-PROTACs) in Cancer Therapy

Proteolysis-targeting chimeras (PROTACs) are heterobifunctional molecules that have the capability to induce specific protein degradation. While playing a revolutionary role in effectively degrading the protein of interest (POI), PROTACs encounter certain limitations that impede their clinical translation. These limitations encompass off-target effects, inadequate cell membrane permeability, and the hook effect. The advent of nanotechnology presents a promising avenue to surmount the challenges associated with conventional PROTACs. The utilization of nano-proteolysis targeting chimeras (nano-PROTACs) holds the potential to enhance specific tissue accumulation, augment membrane permeability, and enable controlled release. Consequently, this approach has the capacity to significantly enhance the controllable degradation of target proteins. Additionally, they enable a synergistic effect by combining with other therapeutic strategies. This review comprehensively summarizes the structural basis, advantages, and limitations of PROTACs. Furthermore, it highlights the latest advancements in nanosystems engineered for delivering PROTACs, as well as the development of nano-sized PROTACs employing nanocarriers as linkers. Moreover, it delves into the underlying principles of nanotechnology tailored specifically for PROTACs, alongside the current prospects of clinical research. In conclusion, the integration of nanotechnology into PROTACs harbors vast potential in enhancing the anti-tumor treatment response and expediting clinical translation.

Suitably Incorporated Hydrophobic, Redox-Active Drug in Poly Lactic Acid-Graphene Nanoplatelet Composite Generates 3D-Printed Medicinal Patch for Electrostimulatory Therapeutics

Polymer carbon composites have been reported for improved mechanical, thermal and electrical properties to provide reduced side effect by 3D printing personalized biomedical drug delivery devices. But control on homogeneity in loading and release of dopants like carbon allotropes and drugs, respectively, in the bulk and on the surface has always been a challenge. Herein, we are reporting a methodological cascade to achieve a model, customizable, 3D printed, homogeneously layered and electrically stimulatory, PLA-Graphene nanoplatelet (hl-PLGR) based drug delivery device, called 3D-est-MediPatch. The medicinal patch has been prepared by 3D-printing a Nic-hl-PLGR composite obtained by incorporating a redox active model drug, niclosamide (Nic) in hl-PLGR. The composite of Nic-hl-PLGR was characterized in three sequentially complex forms─composite film, hot melt extruded (HME) filament, and 3D printed (3DP) patches to understand the effect of filament extrusion and 3D-printing processes on Nic-hl-PLGR composite and overall drug incorporation efficiency and control. The incorporation of graphene was found to improve the homogeneity of the drug, and the hot melt extrusion improved the dispersion of drug and graphene fillers in the composite. The electroresponsive drug release from the Nic-hl-PLGR composite was found to be controllably accelerated compared to the drug release by diffusion, in simulated buffer condition. The released drug concentration was found to reach within the IC50 range for malignant melanoma cell (A375) and showed in vitro selectively, with reduced effects in noncancerous, fibroblast cells (NIH3T3). Further, the feasibility of application for this system was assessed in generating personalized 3D-est-MediPatch for skin, liver and spleen tissues in ex-vivo scenario. It showed excellent feasibility and efficacy of the 3D-est-MediPatch in controlled and personalized release of drugs during electrostimulation. Thus, a model platform, 3D-est-MediPatch, could be achieved by suitably incorporating a hydrophobic, redox-active drug (niclosamide) in poly lactic acid-graphene nanoplatelet composite for electrostimulatory therapeutics with reduced side effects.

Harnessing the Power of Stimuli-Responsive Nanoparticles as an Effective Therapeutic Drug Delivery System

The quest for effective and reliable methods of delivering medications, with the aim of improving delivery of therapeutic agent to the intended location, has presented a demanding yet captivating field in biomedical research. The concept of smart drug delivery systems is an evolving therapeutic approach, serving as a model for directing drugs to specific targets or sites. These systems have been developed to specifically target and regulate the administration of therapeutic substances in a diverse array of chronic conditions, including periodontitis, diabetes, cardiac diseases, inflammatory bowel diseases, rheumatoid arthritis, and different cancers. Nevertheless, numerous comprehensive clinical trials are still required to ascertain both the immediate and enduring impacts of such nanosystems on human subjects. This review delves into the benefits of different drug delivery vehicles, aiming to enhance comprehension of their applicability in addressing present medical requirements. Additionally, it touches upon the current applications of these stimuli-reactive nanosystems in biomedicine and outlines future development prospects.

Tumor Microenvironment-Responsive Polymer-Based RNA Delivery Systems for Cancer Treatment

Ribonucleic acid (RNA) therapeutics offer a broad prospect in cancer treatment. However, their successful application requires overcoming various physiological barriers to effectively deliver RNAs to the target sites. Currently, a number of RNA delivery systems based on polymeric nanoparticles are developed to overcome these barriers in RNA delivery. This work provides an overview of the existing RNA therapeutics for cancer gene therapy, and particularly summarizes those that are entering the clinical phase. This work then discusses the core features and latest research developments of tumor microenvironment-responsive polymer-based RNA delivery carriers which are designed based on the pathological characteristics of the tumor microenvironment. Finally, this work also proposes opportunities for the transformation of RNA therapies into cancer immunotherapy methods in clinical applications.

Self-Assembly of Peptides as an Alluring Approach toward Cancer Treatment and Imaging

Cancer is a severe threat to humans, as it is the second leading cause of death after cardiovascular diseases and still poses the biggest challenge in the world of medicine. Due to its higher mortality rates and resistance, it requires a more focused and productive approach to provide the solution for it. Many therapies promising to deliver favorable results, such as chemotherapy and radiotherapy, have come up with more negatives than positives. Therefore, a new class of medicinal solutions and a more targeted approach is of the essence. This review highlights the alluring properties, configurations, and self-assembly of peptide molecules which benefit the traditional approach toward cancer therapy while sparing the healthy cells in the process. As targeted drug delivery systems, self-assembled peptides offer a wide spectrum of conjugation, biocompatibility, degradability-controlled responsiveness, and biomedical applications, including cancer treatment and cancer imaging.

Design and applications of polymer-like peptides in biomedical nanogels

INTRODUCTION

Polymer nanogels are among the most promising nanoplatforms for use in biomedical applications. The substantial interest for these drug carriers is to enhance the transportation of bioactive substances, reduce the side effects, and achieve optimal action on the curative sites by targeting delivery and triggering the release of the drugs in a controlled and continuous mode.

AREA COVERED

The review discusses the opportunities, applications, and challenges of synthetic polypeptide nanogels in biomedicine, with an emphasis on the recent progress in cancer therapy. It is evidenced by the development of polypeptide nanogels for better controlled drug delivery and release, in complex in vivo microenvironments in biomedical applications.

EXPERT OPINION

Polypeptide nanogels can be developed by choosing the amino acids from the peptide structure that are suitable for the type of application. Using a stimulus - sensitive peptide nanogel, it is possible to obtain the appropriate transport and release of the drug, as well as to achieve desirable therapeutic effects, including safety, specificity, and efficiency. The final system represents an innovative way for local and sustained drug delivery at a specific site of the body.

Cuproptosis: Advances in Stimulus-Responsive Nanomaterials for Cancer Therapy

Cuproptosis, a recently identified non-apoptotic programmed cell death modality, attracts considerable attention in the realm of cancer therapeutics owing to its unique cellular demise mechanisms. Since its initial report in 2022, strategies inducing or amplifying cuproptosis for cancer treatment emerge. The engineering of nano-systems to elicit cuproptosis effectively circumvents constraints associated with conventional small-molecule pharmaceutical interventions, presenting novel prospects for oncological therapy. Stimulus-responsive nanomaterials, leveraging their distinctive spatiotemporal control attributes, are investigated for their role in modulating the induction or augmentation of cuproptosis. In this comprehensive review, the physiological characteristics of cuproptosis, encompassing facets such as copper overload and depletion, coupled with regulatory factors intrinsic to cuproptosis, are expounded upon. Subsequently, design methodologies for stimulus-responsive induction or enhancement of cuproptosis, employing stimuli such as light, ultrasound, X-ray, and the tumor microenvironment, are systematically delineated. This review encompasses intricacies in nanomaterial design, insights into the therapeutic processes, and the associated advantages. Finally, challenges inherent in stimulus-responsive induction/enhancement of cuproptosis are deliberated upon and prospective insights into the future trajectory of copper-mediated cancer therapy are provided.

Smart Nanocarriers for the Treatment of Retinal Diseases

Retinal diseases, such as age-related macular degeneration, diabetic retinopathy, and retinoblastoma, stand as the leading causes of irreversible vision impairment and blindness worldwide. Effectively administering drugs for retinal diseases poses a formidable challenge due to the presence of complex ocular barriers and elimination mechanisms. Over time, various approaches have been developed to fabricate drug delivery systems for improving retinal therapy including virus vectors, lipid nanoparticles, and polymers. However, conventional nanocarriers encounter issues related to the controllability, efficiency, and safety in the retina. Therefore, the development of smart nanocarriers for effective or more invasive long-term treatment remains a desirable goal. Recently, approaches have surfaced for the intelligent design of nanocarriers, leveraging specific responses to external or internal triggers and enabling multiple functions for retinal therapy such as topical administration, prolonged drug release, and site-specific drug delivery. This Review provides an overview of prevalent retinal pathologies and related pharmacotherapies to enhance the understanding of retinal diseases. It also surveys recent developments and strategies employed in the intelligent design of nanocarriers for retinal disease. Finally, the challenges of smart nanocarriers in potential clinical retinal therapeutic applications are discussed to inspire the next generation of smart nanocarriers.

Radiotherapy activates picolinium prodrugs in tumours

Radiotherapy-induced prodrug activation provides an ideal solution to reduce the systemic toxicity of chemotherapy in cancer therapy, but the scope of the radiation-activated protecting groups is limited. Here we present that the well-established photoinduced electron transfer chemistry may pave the way for developing versatile radiation-removable protecting groups. Using a functional reporter assay, N-alkyl-4-picolinium (NAP) was identified as a caging group that efficiently responds to radiation by releasing a client molecule. When evaluated in a competition experiment, the NAP moiety is more efficient than other radiation-removable protecting groups discovered so far. Leveraging this property, we developed a NAP-derived carbamate linker that releases fluorophores and toxins on radiation, which we incorporated into antibody-drug conjugates (ADCs). These designed ADCs were active in living cells and tumour-bearing mice, highlighting the potential to use such a radiation-removable protecting group for the development of next-generation ADCs with improved stability and therapeutic effects.

Modular Fabrication of Bioorthogonal Nanozymes for Biomedical Applications

The incorporation of transition metal catalysts (TMCs) into nanoscaffolds generates nanocatalysts that replicate key aspects of enzymatic behavior. The TMCs can access bioorthogonal chemistry unavailable to living systems. These bioorthogonal nanozymes can be employed as in situ "factories" for generating bioactive molecules where needed. The generation of effective bioorthogonal nanozymes requires co-engineering of the TMC and the nanometric scaffold. This review presents an overview of recent advances in the field of bioorthogonal nanozymes, focusing on modular design aspects of both nanomaterial and catalyst and how they synergistically work together for in situ uncaging of imaging and therapeutic agents.

ortho-Boronic Acid Carbonyl Compounds and Their Applications in Chemical Biology

Iminoboronates and diazaborines are related classes of compounds that feature an imine ortho to an arylboronic acid (iminoboronate) or a hydrazone that cyclizes with an ortho arylboronic acid (diazaborine). Rather than acting as independent chemical motifs, the arylboronic acid impacts the rate of imine/hydrazone formation, hydrolysis, and exchange with competing nucleophiles. Increasing evidence has shown that the imine/hydrazone functionality also impacts arylboronic acid reactivity toward diols and reactive oxygen and nitrogen species (ROS/RNS). Untangling the communication between C=N linked functionalities and arylboronic acids has revealed a powerful and tunable motif for bioconjugation chemistries and other applications in chemical biology. Here, we survey the applications of iminoboronates and diazaborines in these fields with an eye toward understanding their utility as a function of neighboring group effects.

Light-Responsive and Dual-Targeting Liposomes: From Mechanisms to Targeting Strategies

In recent years, nanocarriers have played an ever-increasing role in clinical and biomedical applications owing to their unique physicochemical properties and surface functionalities. Lately, much effort has been directed towards the development of smart, stimuli-responsive nanocarriers that are capable of releasing their cargos in response to specific stimuli. These intelligent-responsive nanocarriers can be further surface-functionalized so as to achieve active tumor targeting in a sequential manner, which can be simply modulated by the stimuli. By applying this methodological approach, these intelligent-responsive nanocarriers can be directed to different target-specific organs, tissues, or cells and exhibit on-demand controlled drug release that may enhance therapeutic effectiveness and reduce systemic toxicity. Light, an external stimulus, is one of the most promising triggers for use in nanomedicine to stimulate on-demand drug release from nanocarriers. Light-triggered drug release can be achieved through light irradiation at different wavelengths, either in the UV, visible, or even NIR region, depending on the photophysical properties of the photo-responsive molecule embedded in the nanocarrier system, the structural characteristics, and the material composition of the nanocarrier system. In this review, we highlighted the emerging functional role of light in nanocarriers, with an emphasis on light-responsive liposomes and dual-targeted stimuli-responsive liposomes. Moreover, we provided the most up-to-date photo-triggered targeting strategies and mechanisms of light-triggered drug release from liposomes and NIR-responsive nanocarriers. Lastly, we addressed the current challenges, advances, and future perspectives for the deployment of light-responsive liposomes in targeted drug delivery and therapy.

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.

Electroactive Polymers for On-Demand Drug Release

Conductive materials have played a significant role in advancing society into the digital era. Such materials are able to harness the power of electricity and are used to control many aspects of daily life. Conductive polymers (CPs) are an emerging group of polymers that possess metal-like conductivity yet retain desirable polymeric features, such as processability, mechanical properties, and biodegradability. Upon receiving an electrical stimulus, CPs can be tailored to achieve a number of responses, such as harvesting energy and stimulating tissue growth. The recent FDA approval of a CP-based material for a medical device has invigorated their research in healthcare. In drug delivery, CPs can act as electrical switches, drug release is achieved at a flick of a switch, thereby providing unprecedented control over drug release. In this review, recent developments in CP as electroactive polymers for voltage-stimuli responsive drug delivery systems are evaluated. The review demonstrates the distinct drug release profiles achieved by electroactive formulations, and both the precision and ease of stimuli response. This level of dynamism promises to yield "smart medicines" and warrants further research. The review concludes by providing an outlook on electroactive formulations in drug delivery and highlighting their integral roles in healthcare IoT.

The Chimera of TPGS and Nanoscale Lipid Carriers as Lymphatic Drug Delivery Vehicles to Fight Metastatic Cancers

The lymphatic system (LS) plays a crucial role in fluid balance, transportation of macromolecules, and immune response. Moreover, LS is a channel for microbial invasion and cancer metastasis. Particularly, solid tumors, including lung, breast, melanoma, and prostate cancers, are metastasized across highways of LS. Subsequently, the fabrication of chimeric lymphatic drug delivery systems (LDDS) is a promising strategy to fight cancer metastasis and control microbial pandemics. In this regard, LDDS, in terms of PEG-nanoscaled lipid carriers, elicited a revolution during the COVID-19 pandemic as cargoes for mRNA vaccines. The drug delivered by the lymphatic pathway escapes first-pass metabolism and enhances the drug's bioavailability. Ample approaches, including synthesis of prodrugs, trigging of chylomicron biosynthesis, and fabrication of nanocarriers, facilitate lymphatic drug delivery. Specifically, nanoscales lipid cargoes have the propensity to lymphatic trafficking. Interestingly, TPGSengineered nanoscale lipid cargoes enhance lymphatic trafficking, increase tissue permeation, and, specifically, uptake. Moreover, they overcome biological barriers, control biodistribution, and enhance organelles localization. Most anticancer agents are non-specific, have low bioavailability, and induced drug resistance. Therefore, TPGS-engineered nanoscale lipid chimeras improve the therapeutic impact of anticancer agents. This review highlights lymphatic cancer metastasis, nanoscales lipid cargoes as LDDS, and their influence on lymphatic trafficking, besides the methods of LDD studies.

Bioresponsive drug delivery systems

In this review, we highlight the potential of stimuli-responsive drug delivery systems (DDSs) to revolutionize healthcare. Through examining pH, temperature, enzyme, and redox responsiveness, the presented case studies highlight the precision and enhanced therapeutic outcomes achievable with these innovative systems. Challenges, such as complex design and bio-based material optimization, underscore the complete journey from bench to bedside. Clinical strides in magnetically and temperature-responsive systems hint at a promising future for healthcare. However, overcoming issues of stability, durability, penetration depth, sensitivity, and active targeting is crucial. The future envisions theranostic systems, amalgamating targeted therapy and diagnosis, for personalized healthcare. Bio-based materials emerge as pivotal, offering a nuanced approach to complex diseases, such as cancer and diabetes, reshaping the healthcare landscape.

One-Pot Synthesis of Affordable Redox-Responsive Drug Delivery System Based on Trithiocyanuric Acid Nanoparticles

Redox-responsive drug delivery systems present a promising avenue for drug delivery due to their ability to leverage the unique redox environment within tumor cells. In this work, we describe a facile and cost-effective one-pot synthesis method for a redox-responsive delivery system based on novel trithiocyanuric acid (TTCA) nanoparticles (NPs). We conduct a thorough investigation of the impact of various synthesis parameters on the morphology, stability, and loading capacity of these NPs. The great drug delivery potential of the system is further demonstrated in vitro and in vivo by using doxorubicin as a model drug. The developed TTCA-PEG NPs show great drug delivery efficiency with minimal toxicity on their own both in vivo and in vitro. The simplicity of this synthesis, along with the promising characteristics of TTCA-PEG NPs, paves the way for new opportunities in the further development of redox-responsive drug delivery systems based on TTCA.

Stimuli-Responsive Polymer-Based Nanosystems for Cancer Theranostics

Stimuli-responsive polymers can respond to internal stimuli, such as reactive oxygen species (ROS), glutathione (GSH), and pH, biological stimuli, such as enzymes, and external stimuli, such as lasers and ultrasound, etc., by changing their hydrophobicity/hydrophilicity, degradability, ionizability, etc., and thus have been widely used in biomedical applications. Due to the characteristics of the tumor microenvironment (TME), stimuli-responsive polymers that cater specifically to the TME have been extensively used to prepare smart nanovehicles for the targeted delivery of therapeutic and diagnostic agents to tumor tissues. Compared to conventional drug delivery nanosystems, TME-responsive nanosystems have many advantages, such as high sensitivity, broad applicability among different tumors, functional versatility, and improved biosafety. In recent years, a great deal of research has been devoted to engineering efficient stimuli-responsive polymeric nanosystems, and significant improvement has been made to both cancer diagnosis and therapy. In this review, we summarize some recent research advances involving the use of stimuli-responsive polymer nanocarriers in drug delivery, tumor imaging, therapy, and theranostics. Various chemical stimuli will be described in the context of stimuli-responsive nanosystems. Accordingly, the functional chemical groups responsible for the responsiveness and the strategies to incorporate these groups into the polymer will be discussed in detail. With the research on this topic expending at a fast pace, some innovative concepts, such as sequential and cascade drug release, NIR-II imaging, and multifunctional formulations, have emerged as popular strategies for enhanced performance, which will also be included here with up-to-date illustrations. We hope that this review will offer valuable insights for the selection and optimization of stimuli-responsive polymers to help accelerate their future applications in cancer diagnosis and treatment.

The potential role of synovial cells in the progression and treatment of osteoarthritis

Osteoarthritis (OA), the commonest arthritis, is characterized by the progressive destruction of cartilage, leading to disability. The Current early clinical treatment strategy for OA often centers on anti-inflammatory or analgesia medication, weight loss, improved muscular function and articular cartilage repair. Although these treatments can relieve symptoms, OA tends to be progressive, and most patients require arthroplasty at the terminal stages of OA. Recent studies have shown a close correlation between joint pain, inflammation, cartilage destruction and synovial cells. Consequently, understanding the potential mechanisms associated with the action of synovial cells in OA could be beneficial for the clinical management of OA. Therefore, this review comprehensively describes the biological functions of synovial cells, the synovium, together with the pathological changes of synovial cells in OA, and the interaction between the cartilage and synovium, which is lacking in the present literature. Additionally, therapeutic approaches based on synovial cells for OA treatment are further discussed from a clinical perspective, highlighting a new direction in the treatment of OA.

Nanomaterial-based ophthalmic drug delivery

The low bioavailability and side effects of conventional drugs for eye disease necessitate the development of efficient drug delivery systems. Accompanying the developments of nanofabrication techniques, nanomaterials have been recognized as promising tools to overcome these challenges due to their flexible and programmable properties. Given the advances achieved in material science, a broad spectrum of functional nanomaterials capable of overcoming various ocular anterior and posterior segment barriers have been explored to satisfy the demands for ocular drug delivery. In this review, we first highlight the unique functions of nanomaterials suitable for carrying and transporting ocular drugs. Then, various functionalization strategies are emphasized to endow nanomaterials with superior performance in enhanced ophthalmic drug delivery. The rational design of several affecting factors is essential for ideal nanomaterial candidates and is depicted as well. Lastly, we introduce the current applications of nanomaterial-based delivery systems in the therapy of different ocular anterior and posterior segment diseases. The limitations of these delivery systems as well as potential solutions are also discussed. This work will inspire innovative design thinking for the development of nanotechnology-mediated strategies for advanced drug delivery and treatment toward ocular diseases.

Exosomes as a Nano-Carrier for Chemotherapeutics: A New Era of Oncology

Despite the considerable advancements in oncology, cancer remains one of the leading causes of death worldwide. Drug resistance mechanisms acquired by cancer cells and inefficient drug delivery limit the therapeutic efficacy of available chemotherapeutics drugs. However, studies have demonstrated that nano-drug carriers (NDCs) can overcome these limitations. In this sense, exosomes emerge as potential candidates for NDCs. This is because exosomes have better organotropism, homing capacity, cellular uptake, and cargo release ability than synthetic NDCs. In addition, exosomes can serve as NDCs for both hydrophilic and hydrophobic chemotherapeutic drugs. Thus, this review aimed to summarize the latest advances in cell-free therapy, describing how the exosomes can contribute to each step of the carcinogenesis process and discussing how these nanosized vesicles could be explored as nano-drug carriers for chemotherapeutics.

Spatiotemporally controlled drug delivery via photothermally driven conformational change of self-integrated plasmonic hybrid nanogels

BACKGROUND

Spatiotemporal regulation is one of the major considerations for developing a controlled and targeted drug delivery system to treat diseases efficiently. Light-responsive plasmonic nanostructures take advantage due to their tunable optical and photothermal properties by changing size, shape, and spatial arrangement.

RESULTS

In this study, self-integrated plasmonic hybrid nanogels (PHNs) are developed for spatiotemporally controllable drug delivery through light-driven conformational change and photothermally-boosted endosomal escape. PHNs are easily synthesized through the simultaneous integration of gold nanoparticles (GNPs), thermo-responsive poly (N-isopropyl acrylamide), and linker molecules during polymerization. Wave-optic simulations reveal that the size of the PHNs and the density of the integrated GNPs are crucial factors in modulating photothermal conversion. Several linkers with varying molecular weights are inserted for the optimal PHNs, and the alginate-linked PHN (A-PHN) achieves more than twofold enhanced heat conversion compared with others. Since light-mediated conformational changes occur transiently, drug delivery is achieved in a spatiotemporally controlled manner. Furthermore, light-induced heat generation from cellular internalized A-PHNs enables pinpoint cytosolic delivery through the endosomal rupture. Finally, the deeper penetration for the enhanced delivery efficiency by A-PHNs is validated using multicellular spheroid.

CONCLUSION

This study offers a strategy for synthesizing light-responsive nanocarriers and an in-depth understanding of light-modulated site-specific drug delivery.

Current advances in nanodrug delivery systems for malaria prevention and treatment

Malaria is a life-threatening, blood-borne disease with over two hundred million cases throughout the world and is more prevalent in Sub-Saharan Africa than anywhere else in the world. Over the years, several treatment agents have been developed for malaria; however, most of these active pharmaceutical ingredients exhibit poor aqueous solubility and low bioavailability and may result in drug-resistant parasites, thus increasing malaria cases and eventually, deaths. Factors such as these in therapeutics have led to a better appreciation of nanomaterials. The ability of nanomaterials to function as drug carriers with a high loading capacity and targeted drug delivery, good biocompatibility, and low toxicity renders them an appealing alternative to conventional therapy. Nanomaterials such as dendrimers and liposomes have been demonstrated to be capable of enhancing the efficacy of antimalarial drugs. This review discusses the recent development of nanomaterials and their benefits in drug delivery for the potential treatment of malaria.

Bacterial Membrane Vesicles as Smart Drug Delivery and Carrier Systems: A New Nanosystems Tool for Current Anticancer and Antimicrobial Therapy

Bacterial membrane vesicles (BMVs) are known to be critical communication tools in several pathophysiological processes between bacteria and host cells. Given this situation, BMVs for transporting and delivering exogenous therapeutic cargoes have been inspiring as promising platforms for developing smart drug delivery systems (SDDSs). In the first section of this review paper, starting with an introduction to pharmaceutical technology and nanotechnology, we delve into the design and classification of SDDSs. We discuss the characteristics of BMVs including their size, shape, charge, effective production and purification techniques, and the different methods used for cargo loading and drug encapsulation. We also shed light on the drug release mechanism, the design of BMVs as smart carriers, and recent remarkable findings on the potential of BMVs for anticancer and antimicrobial therapy. Furthermore, this review covers the safety of BMVs and the challenges that need to be overcome for clinical use. Finally, we discuss the recent advancements and prospects for BMVs as SDDSs and highlight their potential in revolutionizing the fields of nanomedicine and drug delivery. In conclusion, this review paper aims to provide a comprehensive overview of the state-of-the-art field of BMVs as SDDSs, encompassing their design, composition, fabrication, purification, and characterization, as well as the various strategies used for targeted delivery. Considering this information, the aim of this review is to provide researchers in the field with a comprehensive understanding of the current state of BMVs as SDDSs, enabling them to identify critical gaps and formulate new hypotheses to accelerate the progress of the field.

Stimuli-Responsive Nanotherapeutics for Treatment and Diagnosis of Stroke

Stroke is the second most common medical emergency and constitutes a significant cause of global morbidity. The conventional stroke treatment strategies, including thrombolysis, antiplatelet therapy, endovascular thrombectomy, neuroprotection, neurogenesis, reducing neuroinflammation, oxidative stress, excitotoxicity, hemostatic treatment, do not provide efficient relief to the patients due to lack of appropriate delivery systems, large doses, systemic toxicity. In this context, guiding the nanoparticles toward the ischemic tissues by making them stimuli-responsive can be a turning point in managing stroke. Hence, in this review, we first outline the basics of stroke, including its pathophysiology, factors affecting its development, current treatment therapies, and their limitations. Further, we have discussed stimuli-responsive nanotherapeutics used for diagnosing and treating stroke with challenges ahead for the safe use of nanotherapeutics.

Nanocarriers overcoming biological barriers induced by multidrug resistance of chemotherapeutics in 2D and 3D cancer models

Multidrug resistance (MDR) is currently a big challenge in cancer therapy and limits its success in several patients. Tumors use the MDR mechanisms to colonize the host and reduce the efficacy of chemotherapeutics that are injected as single agents or combinations. MDR mechanisms are responsible for inactivation of drugs and formbiological barriers in cancer like the drug efflux pumps, aberrant extracellular matrix, hypoxic areas, altered cell death mechanisms, etc. Nanocarriers have some potential to overcome these barriers and improve the efficacy of chemotherapeutics. In fact, they are versatile and can deliver natural and synthetic biomolecules, as well as RNAi/DNAi, thus providing a controlled release of drugs and a synergistic effect in tumor tissues. Biocompatible and safe multifunctional biopolymers, with or without specific targeting molecules, modify the surface and interface properties of nanocarriers. These modifications affect the interaction of nanocarriers with cellular models as well as the selection of suitable models for in vitro experiments. MDR cancer cells, and particularly their 2D and 3D models, in combination with anatomical and physiological structures of tumor tissues, can boost the design and preparation of nanomedicines for anticancer therapy. 2D and 3D cancer cell cultures are suitable models to study the interaction, internalization, and efficacy of nanocarriers, the mechanisms of MDR in cancer cells and tissues, and they are used to tailor a personalized medicine and improve the efficacy of anticancer treatment in patients. The description of molecular mechanisms and physio-pathological pathways of these models further allow the design of nanomedicine that can efficiently overcome biological barriers involved in MDR and test the activity of nanocarriers in 2D and 3D models of MDR cancer cells.

Rational Understanding of Loading and Release of Doxorubicin by UV-Light- and pH-Responsive Poly(NIPAM-co-SPMA) Micelle-like Aggregates

A deep understanding of the interactions between micelle-like aggregates and antineoplastic drugs is paramount to control their adequate delivery. Herein, Poly(NIPAM-co-SPMA) copolymer nanocarriers were synthesized according to our previous published methodology, and the loading and release of poorly and highly water-soluble doxorubicin forms (Dox and Dox-HCl, respectively) were evaluated upon UV light irradiation and pH-variation stimuli. Capillary electrophoresis (CE) coupled to a fluorescence detector (LIF) allowed us to specifically characterize these systems and deeply study the loading and release processes. For this purpose, varying concentrations of doxorubicin were tested, and the loading/release rates were indirectly quantified thanks to the "free" doxorubicin concentration in solution. This study highlighted that Dox loading (9.4 μg/mg) was more effective than Dox-HCl loading (5.5 μg/mg). In contrast, 68 and 74% of Dox-HCl were respectively released after 2 min upon pH variation (from 7.4 to 6.0) and combined UV + pH 6.0 stimuli, while only 27% of Dox was invariably released upon application of the same stimuli. These results are coherent with the characteristics of both DoxHCl and Dox: Electrostatic interactions between Dox-HCl and the micelle-membrane structure (NIPAM) seemed predominant, while hydrophobic interactions were expected between Dox and the SP moieties at the inner part of the micelle-like aggregate, leading to different behaviors in both loading and release of the two doxorubicin forms. For doxorubicin loading concentrations higher than 3 μM, the electrophoretic profiles presented an additional peak. Thanks to CE characterizations, this peak was attributed to the formation of a complex formed between the nonaggregated copolymer and the doxorubicin molecules. This report therefore undergoes deep characterization of the dynamic formation of different micelle/drug complexes involved in the global drug-delivery behavior and therefore contributes to the development of more effective stimuli-responsive nanocarriers.

pH-Responsive and Mucoadhesive Nanoparticles for Enhanced Oral Insulin Delivery: The Effect of Hyaluronic Acid with Different Molecular Weights

Drug degradation at low pH and rapid clearance from intestinal absorption sites are the main factors limiting the development of oral macromolecular delivery systems. Based on the pH responsiveness and mucosal adhesion of hyaluronic acid (HA) and poly[2-(dimethylamino)ethyl methacrylate] (PDM), we prepared three HA–PDM nano-delivery systems loaded with insulin (INS) using three different molecular weights (MW) of HA (L, M, H), respectively. The three types of nanoparticles (L/H/M-HA–PDM–INS) had uniform particle sizes and negatively charged surfaces. The optimal drug loadings of the L-HA–PDM–INS, M-HA–PDM–INS, H-HA–PDM–INS were 8.69 ± 0.94%, 9.11 ± 1.03%, and 10.61 ± 1.16% (w/w), respectively. The structural characteristics of HA–PDM–INS were determined using FT-IR, and the effect of the MW of HA on the properties of HA–PDM–INS was investigated. The release of INS from H-HA–PDM–INS was 22.01 ± 3.84% at pH 1.2 and 63.23 ± 4.10% at pH 7.4. The protective ability of HA–PDM–INS with different MW against INS was verified by circular dichroism spectroscopy and protease resistance experiments. H-HA–PDM–INS retained 45.67 ± 5.03% INS at pH 1.2 at 2 h. The biocompatibility of HA–PDM–INS, regardless of the MW of HA, was demonstrated using CCK-8 and live–dead cell staining. Compared with the INS solution, the transport efficiencies of L-HA–PDM–INS, M-HA–PDM–INS, and H-HA–PDM–INS increased 4.16, 3.81, and 3.10 times, respectively. In vivo pharmacodynamic and pharmacokinetic studies were performed in diabetic rats following oral administration. H-HA–PDM–INS exhibited an effective hypoglycemic effect over a long period, with relative bioavailability of 14.62%. In conclusion, these simple, environmentally friendly, pH-responsive, and mucoadhesive nanoparticles have the potential for industrial development. This study provides preliminary data support for oral INS delivery.

Graphene-based nanomaterials for stimuli-sensitive controlled delivery of therapeutic molecules

Stimuli-responsive drug delivery has attracted tremendous attention in the past decades. It provides a spatial- and temporal-controlled release in response to different triggers, thus enabling highly efficient drug delivery and minimizing drug side effects. Graphene-based nanomaterials have been broadly explored, and they show great potential in smart drug delivery due to their stimuli-responsive behavior and high loading capacity for an extended range of drug molecules. These characteristics are a result of high surface area, mechanical stability and chemical stability, and excellent optical, electrical, and thermal properties. Their great and infinite functionalization potential also allows them to be integrated into several types of polymers, macromolecules, or other nanoparticles, leading to the fabrication of novel nanocarriers with enhanced biocompatibility and trigger-sensitive properties. Thus, numerous studies have been dedicated to graphene modification and functionalization. In the current review, we introduce graphene derivatives and different graphene-based nanomaterials utilized in drug delivery and discuss the most important advances in their functionalization and modification. Also, their potential and progress in an intelligent drug release in response to different types of stimuli either endogenous (pH, redox conditions, and reactive oxygen species (ROS)) or exogenous (temperature, near-infrared (NIR) radiation, and electric field) will be debated.

Cyclodextrins as eminent constituents in nanoarchitectonics for drug delivery systems

Cyclodextrins have been widely employed for drug delivery systems (DDSs) in which drugs are selectively delivered to a target site in the body. Recent interest has been focused on the construction of cyclodextrin-based nanoarchitectures that show sophisticated DDS functions. These nanoarchitectures are precisely fabricated based on three important features of cyclodextrins, namely (1) the preorganized three-dimensional molecular structure of nanometer size, (2) the easy chemical modification to introduce functional groups, and (3) the formation of dynamic inclusion complexes with various guests in water. With the use of photoirradiation, drugs are released from cyclodextrin-based nanoarchitectures at designated timing. Alternatively, therapeutic nucleic acids are stably protected in the nanoarchitectures and delivered to the target site. The efficient delivery of the CRISPR-Cas9 system for gene editing was also successful. Even more complicated nanoarchitectures can be designed for sophisticated DDSs. Cyclodextrin-based nanoarchitectures are highly promising for future applications in medicine, pharmaceutics, and other relevant fields.

Ferroptosis: challenges and opportunities for nanomaterials in cancer therapy

Ferroptosis, a completely new form of regulated cell death, is mainly caused by an imbalance between oxidative damage and reductive protection and has shown great anti-cancer potential. However, existing small-molecule ferroptosis inducers have various limitations, such as poor water solubility, drug resistance and low targeting ability, hindering their clinical applications. Nanotechnology provides new opportunities for ferroptosis-driven tumor therapy. Especially, stimuli-responsive nanomaterials stand out among others and have been widely researched because of their unique spatiotemporal control advantages. Therefore, it's necessary to summarize the application of those stimuli-responsive nanomaterials in ferroptosis. Here, we describe the physiological feature of ferroptosis and illustrate the current challenges to induce ferroptosis for cancer therapy. Then, nanomaterials that induce ferroptosis are classified and elaborated according to the external and internal stimuli. Finally, the future perspectives in the field are proposed. We hope this review facilitates paving the way for the design of intelligent nano-ferroptosis inducers.

Recent Advances in Targeted Nanocarriers for the Management of Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a life-threatening form of breast cancer which has been found to account for 15% of all the subtypes of breast cancer. Currently available treatments are significantly less effective in TNBC management because of several factors such as poor bioavailability, low specificity, multidrug resistance, poor cellular uptake, and unwanted side effects being the major ones. As a rapidly growing field, nano-therapeutics offers promising alternatives for breast cancer treatment. This platform provides a suitable pathway for crossing biological barriers and allowing sustained systemic circulation time and an improved pharmacokinetic profile of the drug. Apart from this, it also provides an optimized target-specific drug delivery system and improves drug accumulation in tumor cells. This review provides insights into the molecular mechanisms associated with the pathogenesis of TNBC, along with summarizing the conventional therapy and recent advances of different nano-carriers for the management of TNBC.

Recent Advances in Mesoporous Silica Nanoparticle-Mediated Drug Delivery for Breast Cancer Treatment

Breast cancer (BC) currently occupies the second rank in cancer-related global female deaths. Although consistent awareness and improved diagnosis have reduced mortality in recent years, late diagnosis and resistant response still limit the therapeutic efficacy of chemotherapeutic drugs (CDs), leading to relapse with consequent invasion and metastasis. Treatment with CDs is indeed well-versed but it is badly curtailed with accompanying side effects and inadequacies of site-specific drug delivery. As a result, drug carriers ensuring stealth delivery and sustained drug release with improved pharmacokinetics and biodistribution are urgently needed. Core-shell mesoporous silica nanoparticles (MSNPs) have recently been a cornerstone in this context, attributed to their high surface area, low density, robust functionalization, high drug loading capacity, size-shape-controlled functioning, and homogeneous shell architecture, enabling stealth drug delivery. Recent interest in using MSNPs as drug delivery vehicles has been due to their functionalization and size-shape-driven versatilities. With such insights, this article focuses on the preparation methods and drug delivery mechanisms of MSNPs, before discussing their emerging utility in BC treatment. The information compiled herein could consolidate the database for using inorganic nanoparticles (NPs) as BC drug delivery vehicles in terms of design, application and resolving post-therapy complications.

Concomitant delivery of doxorubicin and cisplatin through liposome-based thermosensitive nanoparticles: perspective in the treatment of cancer in animal models

The temperature sensitive liposomal formulations are a promising tool to improve the therapeutic index of the drugs with minimal toxicity. The aim of this study was to investigate the potential of concomitant delivery of cisplatin (Cis) and doxorubicin (Dox) containing thermosensitive liposomes (TSLs) with mild hyperthermia against cancer in vitro and in vivo. The polyethylene glycol coated DPPC/DSPC, thermosensitive and DSPC, non-thermosensitive liposomes incorporating Cis and Dox were prepared and characterized. A conventional Differential Scanning Calorimetry (DSC) technique and Fourier Transform Infrared Spectroscopy (FT-IR) were applied to study drug-phospholipid interaction and compatibility. The chemotherapeutic efficacy of these formulations was evaluated in benzo[a]pyrene (BaP) induced fibrosarcoma under hyperthermic condition. The size diameter of prepared thermosensitive liposomes was measured to be 120 ± 10 nm. The DSC data exhibited the changes in the curves of DSPC + Dox and DSPC + Cis while comparing the pure DSPC and drugs. However, the FITR showed same spectrum of phospholipids and drugs individually and in the mixture as well. The data showed higher efficacy of Cis-Dox-TSL as 84% inhibition in tumor growth was recorded in this group of animals in hyperthermic condition. The Kaplan-Meir curve revealed, 100% and 80% survival of the animals in the groups treated with Cis-Dox-TSL under hyperthermia and Cis-Dox-NTSL without hyperthermia, respectively. However, Cis-TSL as well as Dox-TSL exhibited 50% survival, while only 20% survival was recorded in the groups of animals treated with Dox-NTSL and Cis-NTSL. The flow cytometry analysis revealed that Cis-Dox-NTSL augments the induction of apoptosis in the tumor cells which was recorded as 18%. As expected, Cis-Dox-TSL showed great potential as 39% of cells were measured as apoptotic cells, significantly very high in comparison to Cis-Dox-NTSL, Dox-TSL and Cis-TSL as well. The apoptotic analysis of the cells by flow cytometry clearly indicated the effect of hyperthermia during the treatment while Cis-Dox-TSL formulation was administered. Finally, the immunohistochemical analysis of the tumor tissues by confocal microscopy exhibited several fold increases in the expression of pAkt in the animals treated with vehicles in Sham-NTSL as well as Sham-TSL. However, Cis-Dox-TSL showed great reduction in the expression of Akt, as it declined by 11-fold. The results of the present study directed the role of concomitant delivery doxorubicin and cisplatin containing thermosensitive liposomes under hyperthermic conditions for the development of a novel therapeutic strategy for the treatment of cancer.

Stimuli-responsive and biomimetic delivery systems for sepsis and related complications

Sepsis, a consequence of an imbalanced immune response to infection, is currently one of the leading causes of death globally. Despite advances in the discoveries of potential targets and nanotechnology, sepsis still lacks effective drug delivery systems for optimal treatment. Stimuli-responsive and biomimetic nano delivery systems, specifically, are emerging as advanced bio-inspired nanocarriers for enhancing the treatment of sepsis. Herein, we present a critical review of different stimuli-responsive systems, including pH-; enzyme-; ROS- and toxin-responsive nanocarriers, reported in the delivery of therapeutics for sepsis. Biomimetic nanocarriers, utilizing natural pathways in the inflammatory cascade to optimize sepsis therapy, are also reviewed, in addition to smart, multifunctional vehicles. The review highlights the nanomaterials designed for constructing these systems; their physicochemical properties; the mechanisms of drug release; and their potential for enhancing the therapeutic efficacy of their cargo. Current challenges are identified and future avenues for research into the optimization of bio-inspired nano delivery systems for sepsis are also proposed. This review confirms the potential of stimuli-responsive and biomimetic nanocarriers for enhanced therapy against sepsis and related complications.

Photonic and magnetic materials for on-demand local drug delivery

Nanomedicine has been considered a promising tool for biomedical research and clinical practice in the 21st century because of the great impact nanomaterials could have on human health. The generation of new smart nanomaterials, which enable time- and space-controlled drug delivery, improve the limitations of conventional treatments, such as non-specific targeting, poor biodistribution and permeability. These smart nanomaterials can respond to internal biological stimuli (pH, enzyme expression and redox potential) and/or external stimuli (such as temperature, ultrasound, magnetic field and light) to further the precision of therapies. To this end, photonic and magnetic nanoparticles, such as gold, silver and iron oxide, have been used to increase sensitivity and responsiveness to external stimuli. In this review, we aim to report the main and most recent systems that involve photonic or magnetic nanomaterials for external stimulus-responsive drug release. The uniqueness of this review lies in highlighting the versatility of integrating these materials within different carriers. This leads to enhanced performance in terms of in vitro and in vivo efficacy, stability and toxicity. We also point out the current regulatory challenges for the translation of these systems from the bench to the bedside, as well as the yet unresolved matter regarding the standardization of these materials.

Recent Advances in Stimuli-Responsive Doxorubicin Delivery Systems for Liver Cancer Therapy

Doxorubicin (DOX) is one of the most commonly used drugs in liver cancer. Unfortunately, the traditional chemotherapy with DOX presents many limitations, such as a systematic release of DOX, affecting both tumor tissue and healthy tissue, leading to the apparition of many side effects, multidrug resistance (MDR), and poor water solubility. Furthermore, drug delivery systems' responsiveness has been intensively studied according to the influence of different internal and external stimuli on the efficiency of therapeutic drugs. In this review, we discuss both internal stimuli-responsive drug-delivery systems, such as redox, pH and temperature variation, and external stimuli-responsive drug-delivery systems, such as the application of magnetic, photo-thermal, and electrical stimuli, for the controlled release of Doxorubicin in liver cancer therapy, along with the future perspectives of these smart delivery systems in liver cancer therapy.

New anti-cancer explorations based on metal ions

Due to the urgent demand for more anti-cancer methods, the new applications of metal ions in cancer have attracted increasing attention. Especially the three kinds of the new mode of cell death, including ferroptosis, calcicoptosis, and cuproptosis, are of great concern. Meanwhile, many metal ions have been found to induce cell death through different approaches, such as interfering with osmotic pressure, triggering biocatalysis, activating immune pathways, and generating the prooxidant effect. Therefore, varieties of new strategies based on the above approaches have been studied and applied for anti-cancer applications. Moreover, many contrast agents based on metal ions have gradually become the core components of the bioimaging technologies, such as MRI, CT, and fluorescence imaging, which exhibit guiding significance for cancer diagnosis. Besides, the new nano-theranostic platforms based on metal ions have experimentally shown efficient response to endogenous and exogenous stimuli, which realizes simultaneous cancer therapy and diagnosis through a more controlled nano-system. However, most metal-based agents have still been in the early stages, and controlled clinical trials are necessary to confirm or not the current expectations. This article will focus on these new explorations based on metal ions, hoping to provide some theoretical support for more anti-cancer ideas.

Smart and Multi-Functional Magnetic Nanoparticles for Cancer Treatment Applications: Clinical Challenges and Future Prospects

Iron oxide nanoparticle (IONPs) have become a subject of interest in various biomedical fields due to their magnetism and biocompatibility. They can be utilized as heat mediators in magnetic hyperthermia (MHT) or as contrast media in magnetic resonance imaging (MRI), and ultrasound (US). In addition, their high drug-loading capacity enabled them to be therapeutic agent transporters for malignancy treatment. Hence, smartening them allows for an intelligent controlled drug release (CDR) and targeted drug delivery (TDD). Smart magnetic nanoparticles (SMNPs) can overcome the impediments faced by classical chemo-treatment strategies, since they can be navigated and release drug via external or internal stimuli. Recently, they have been synchronized with other modalities, e.g., MRI, MHT, US, and for dual/multimodal theranostic applications in a single platform. Herein, we provide an overview of the attributes of MNPs for cancer theranostic application, fabrication procedures, surface coatings, targeting approaches, and recent advancement of SMNPs. Even though MNPs feature numerous privileges over chemotherapy agents, obstacles remain in clinical usage. This review in particular covers the clinical predicaments faced by SMNPs and future research scopes in the field of SMNPs for cancer theranostics.

A Review of Multifunction Smart Nanoparticle based Drug Delivery Systems

Cancer nano-therapeutics are rapidly evolving and are often used to overcome a number of concerns with traditional drug delivery methods, including non-specific drug targeting and distribution, low oral bioavailability, and poor hydrophilicity. Modern nano-based targeting techniques have been developed as a result of advances in nano vehicle engineering and materials science, which may bring people with cancer a new hope. Clinical trials have been authorized for a number of medicinal nanocarriers. Nanocarriers with the best feasible size and surface attributes have been developed to optimize biodistribution and increase blood circulation duration. Nanotherapeutics can carry preloaded active medicine towards cancerous cells by preferentially leveraging the specific physiopathology of malignancies. In contrast to passive targeting, active targeting strategies involving antigens or ligands, developed against specific tumor sites, boost the selectivity of these curative nanovehicles. Another barrier that nanoparticles may resolve or lessen is drug resistance. Multifunctional and complex nanoparticles are currently being explored and are predicted to usher in a new era of nanoparticles that will allow for more individualized and customized cancer therapy. The potential prospects and opportunities of stimuli-triggered nanosystems in therapeutic trials are also explored in this review.

Strategies and progresses for enhancing targeted antibiotic delivery

Antibiotic resistance is a global health issue and a potential risk for society. Antibiotics administered through conventional formulations are devoid of targeting effect and often spread to various undesired body sites, leading to sub-lethal concentrations at the site of action and thus resulting in emergence of resistance, as well as side effects. Moreover, we have a very slim antibiotic pipeline. Drug-delivery systems have been designed to control the rate, time, and site of drug release, and innovative approaches for antibiotic delivery provide a glint of hope for addressing these issues. This review elaborates different delivery strategies and approaches employed to overcome the limitations of conventional antibiotic therapy. These include antibiotic conjugates, prodrugs, and nanocarriers for local and targeted antibiotic release. In addition, a wide range of stimuli-responsive nanocarriers and biological carriers for targeted antibiotic delivery are discussed. The potential advantages and limitations of targeted antibiotic delivery strategies are described along with possible solutions to avoid these limitations. A number of antibiotics successfully delivered through these approaches with attained outcomes and potentials are reviewed.

Multifunctional stimuli-responsive hybrid nanogels for cancer therapy: Current status and challenges

With cancer research shifting focus to achieving multifunctionality in cancer treatment strategies, hybrid nanogels are making a rapid rise to the spotlight as novel, multifunctional, stimuli-responsive, and biocompatible cancer therapeutic strategies. They can possess cancer cell-specific cytotoxic effects themselves, carry drugs or enzymes that can produce cytotoxic effects, improve imaging modalities, and target tumor cells over normal cells. Hybrid nanogels bring together a wide range of desirable properties for cancer treatment such as stimuli-responsiveness, efficient loading and protection of molecules such as drugs or enzymes, and effective crossing of cellular barriers among other properties. Despite their promising abilities, hybrid nanogels are still far from being used in the clinic, and their available data remains relatively limited. However, many studies can be done to facilitate this clinical transition. This review is critically summarizing and analyzing the recent information and progress on the use of hybrid nanogels particularly inorganic nanoparticle-based and organic nanoparticle-based hybrid nanogels in the field of oncology and future directions to aid in transferring those results to the clinic. This work concludes that the future of hybrid nanogels is greatly impacted by therapeutic and non-therapeutic factors. Therapeutic factors include the lack of hemocompatibility studies, acute and chronic toxicological studies, and information on agglomeration capability and extent, tumor heterogeneity, interaction with proteins in physiological fluids, endocytosis-exocytosis, and toxicity of the nanogels' breakdown products. Non-therapeutic factors include the lack of clear regulatory guidelines and standardized assays, limitations of animal models, and difficulties associated with good manufacture practices (GMP).