Surface receptor‐mediated targeted drug delivery systems for enhanced cancer treatment: A state‐of‐the‐art review

Fabrication of folic acid-conjugated pyrimidine-2(5H)-thione-encapsulated curdlan gum-PEGamine nanoparticles for folate receptor targeting breast cancer cells

In this study 5-((2-((3-methoxy benzylidene)-amino)-phenyl)-diazenyl)-4,6-diphenyl pyrimidine-2(5H)-thione was synthesized. The pharmacological applications of pyrimidine analogs are restricted due to their poor pharmacokinetic properties. As a solution, a microbial exopolysaccharide (curdlan gum) was used to synthesize folic acid-conjugated pyrimidine-2(5H)-thione-encapsulated curdlan gum-PEGamine nanoparticles (FA-Py-CG-PEGamine NPs). The results of physicochemical properties revealed that the fabricated FA-Py-CG-PEGamine NPs were between 100 and 400 nm in size with a majorly spherical shaped, crystalline nature, and the encapsulation efficiency and loading capacity were 79.04 ± 0.79 %, and 8.12 ± 0.39 % respectively. The drug release rate was significantly higher at pH 5.4 (80.14 ± 0.79 %) compared to pH 7.2. The cytotoxic potential of FA-Py-CG-PEGamine NPs against MCF-7 cells potentially reduced the number of cells after 24 h with 42.27 μg × mL-1 as IC50 value. The higher intracellular accumulation of pyrimidine-2(5H)-thione in MCF-7 cells leads to apoptosis, observed by AO/EBr staining and flow cytometry analysis. The highest pyrimidine-2(5H)-thione internalization in MCF-7 cells may be due to folate conjugated on the surface of curdlan gum nanoparticles. Further, internalized pyrimidine-2(5H)-thione increases the intracellular ROS level, leading to apoptosis and inducing the decalin in mitochondrial membrane potential. These outcomes demonstrated that the FA-Py-CG-PEGamine NPs were specificity-targeting folate receptors on the plasma membranes of MCF-7 Cells.

Research Advances of Lipid Nanoparticles in the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a common type of gastrointestinal tract (GIT) cancer and poses an enormous threat to human health. Current strategies for metastatic colorectal cancer (mCRC) therapy primarily focus on chemotherapy, targeted therapy, immunotherapy, and radiotherapy; however, their adverse reactions and drug resistance limit their clinical application. Advances in nanotechnology have rendered lipid nanoparticles (LNPs) a promising nanomaterial-based drug delivery system for CRC therapy. LNPs can adapt to the biological characteristics of CRC by modifying their formulation, enabling the selective delivery of drugs to cancer tissues. They overcome the limitations of traditional therapies, such as poor water solubility, nonspecific biodistribution, and limited bioavailability. Herein, we review the composition and targeting strategies of LNPs for CRC therapy. Subsequently, the applications of these nanoparticles in CRC treatment including drug delivery, thermal therapy, and nucleic acid-based gene therapy are summarized with examples provided. The last section provides a glimpse into the advantages, current limitations, and prospects of LNPs in the treatment of CRC.

Advancements in the Synthesis and Functionalization of Zinc Oxide-Based Nanomaterials for Enhanced Oral Cancer Therapy

The fabrication of zinc oxide-based nanomaterials (including natural and synthetic polymers like sulfated polysaccharide, chitosan, and polymethyl methacrylate) has potential to improve oral cancer treatment strategies. This comprehensive review explores the diverse synthesis methods employed to fabricate zinc oxide nanomaterials tailored for oral cancer applications. Several synthesis processes, particularly sol-gel, hydrothermal, and chemical vapor deposition approaches, are thoroughly studied, highlighting their advantages and limitations. The review also examines how synthesis parameters, such as precursor selection, the reaction temperature, and growth conditions, influence both the physicochemical attributes and biological efficacy of the resulting nanomaterials. Furthermore, recent advancements in surface functionalization and modification strategies targeted at improving the targeting specificity and pharmaceutical effectiveness of zinc oxide-based nanomaterials in oral cancer therapy are elucidated. Additionally, the review provides insights into the existing issues and prospective views in the field, emphasizing the need for further research to optimize synthesis methodologies and elucidate the mechanisms underlying the efficacy of zinc oxide-based nanoparticles in oral cancer therapy.

Preparation of Liposome Gel by Calcium Cross-Linking Induces the Long-Term Release of DOX to Improve the Antitumor Effect

Doxorubicin (DOX) is one of the most commonly used anticancer drugs; however, its clinical application is greatly limited due to its toxicity and chemotherapy resistance. The delivery of DOX by liposomes (Lipos) can improve the blood circulation time in vivo and reduce toxic side effects, but the drug's accumulation in the tumor is often insufficient for effective treatment. In this study, we present a calcium cross-linked liposome gel for the encapsulation of DOX, demonstrating its superior long-term release capabilities compared to conventional Lipos. By leveraging this enhanced long-term release, we can enhance drug accumulation within tumors, ultimately leading to improved antitumor efficacy. Lipos were prepared using the thin-film dispersion method in this study. We utilized the ion-responsiveness of glutathione-gelatin (GSH-GG) to form the gel outside the Lipos and named the nanoparticles coated with GSH-GG on the outside of Lipos as Lipos@GSH-GG. The average size of Lipos@GSH-GG was around 342.9 nm, with a negative charge of -25.6 mV. The in vitro experiments revealed that Lipos@GSH-GG exhibited excellent biocompatibility and slower drug release compared to conventional Lipos. Further analysis of cellular uptake and cytotoxicity demonstrated that Lipos@GSH-GG loading DOX (DOX&Lipos@GSH-GG) exhibited superior long-term release effects and lower toxic side effects compared to Lipos loading DOX (DOX&Lipos). Additionally, the findings regarding the long-term release effect in vivo and the tumor accumulation within tumor-bearing mice of Lipos@GSH-GG suggested that, compared to Lipos, it demonstrated superior long-term release capabilities and achieved greater drug accumulation within tumors. In vivo antitumor efficacy experiments showed that DOX&Lipos@GSH-GG demonstrated superior antitumor efficacy to DOX&Lipos. Our study highlights Lipos@GSH-GG as a promising nanocarrier with the potential to enhance efficacy and safety by means of long-term release effects and may offer an alternative approach for effective antitumor therapy in the future.

Tumor Microenvironment-Regulating Two-Photon Probe Based on Bimetallic Post-Coordinated MOF Facilitating the Dual-Modal and Deep Imaging-Guided Synergistic Therapies

The intricate tumor microenvironment (TME) always brings about unsatisfactory therapeutic effects for treatments, although nanomedicines have been demonstrated to be highly beneficial for synergistic therapies to avoid the side effects caused by the complexity and heterogeneity of cancer. Developing nanotheranostics with the functionalities of both synergistic therapies and TME regulation is a good strategy but is still in its infancy. Herein, an "all-in-one" nanoplatform for integrated diagnosis and treatment, namely, Carrier@ICG@DOX@FA (CIDF), is constructed. Benefiting from the bimetallic coordination of Eu3+-HTHA (4,4,4-trifluoro-1-(9-hexylcarbazol-3-yl)-1,3-butanedione) and Fe3+ with the ligands in UiO-67, CIDF can simultaneously achieve two-photon fluorescence imaging, fluorescent lifetime imaging in deep tumors, and regulation of TME. Owing to its porosity, CIDF can encapsulate indocyanine green as photosensitizers and doxorubicin as chemotherapeutic agent, further realizing light-controlled drug release. Moreover, CIDF exhibited good biocompatibility and tumor targeting by coating with folic-acid-modified polymers. Both in vitro and in vivo experiments demonstrate the excellent therapeutic efficacy of CIDF through dual-modal-imaging-guided synergistic photothermal-, photodynamic-, and chemotherapy. CIDF provides a new paradigm for the construction of TME-regulated synergistic nanotheranostics and realizes the complete elimination of tumors without recurrence.

Clinical immunotherapy in pancreatic cancer

Pancreatic cancer remains a challenging disease with limited treatment options, resulting in high mortality rates. The predominant approach to managing pancreatic cancer patients continues to be systemic cytotoxic chemotherapy. Despite substantial advancements in immunotherapy strategies for various cancers, their clinical utility in pancreatic cancer has proven less effective and durable. Whether administered as monotherapy, employing immune checkpoint inhibitors, tumor vaccines, chimeric antigen receptors T cells, or in combination with conventional chemoradiotherapy, the clinical outcomes remain underwhelming. Extensive preclinical experiments and clinical trials in the realm of pancreatic cancer have provided valuable insights into the complexities of immunotherapy. Chief among the hurdles are the immunosuppressive tumor microenvironment, limited immunogenicity, and the inherent heterogeneity of pancreatic cancer. In this comprehensive review, we provide an overview and critical analysis of current clinical immunotherapy strategies for pancreatic cancer, emphasizing their endeavors to overcome immunotherapy resistance. Particular focus is placed on strategies aimed at reshaping the immunosuppressive microenvironment and enhancing T cell-mediated tumor cell killing. Ultimately, through deeper elucidation of the underlying pathogenic mechanisms of pancreatic cancer and the refinement of therapeutic approaches, we anticipate breakthroughs that will pave the way for more effective treatments in this challenging disease.

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

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

Biotin conjugates in targeted drug delivery: is it mediated by a biotin transporter, a yet to be identified receptor, or (an)other unknown mechanism(s)?

Conjugation of drugs with biotin is a widely studied strategy for targeted drug delivery. The structure-activity relationship (SAR) studies through H3-biotin competition experiments conclude with the presence of a free carboxylic acid being essential for its uptake via the sodium-dependent multivitamin transporter (SMVT, the major biotin transporter). However, biotin conjugation with a payload requires modification of the carboxylic acid to an amide or ester group. Then, there is the question as to how/whether the uptake of biotin conjugates goes through the SMVT. If not, then what is the mechanism? Herein, we present known uptake mechanisms of biotin and its applications reported in the literature. We also critically analyse possible uptake mechanism(s) of biotin conjugates to address the disconnect between the results from SMVT-based SAR and "biotin-facilitated" targeted drug delivery. We believe understanding the uptake mechanism of biotin conjugates is critical for their future applications and further development.

Nanotechnology-Based Strategies in Parasitic Disease Management: From Prevention to Diagnosis and Treatment

Parasitic infections are a major global health issue causing significant mortality and morbidity. Despite substantial advances in the diagnostics and treatment of these diseases, the currently available options fall far short of expectations. From diagnosis and treatment to prevention and control, nanotechnology-based techniques show promise as an alternative approach. Nanoparticles can be designed with specific properties to target parasites and deliver antiparasitic medications and vaccines. Nanoparticles such as liposomes, nanosuspensions, polymer-based nanoparticles, and solid lipid nanoparticles have been shown to overcome limitations such as limited bioavailability, poor cellular permeability, nonspecific distribution, and rapid drug elimination from the body. These nanoparticles also serve as nanobiosensors for the early detection and treatment of these diseases. This review aims to summarize the potential applications of nanoparticles in the prevention, diagnosis, and treatment of parasitic diseases such as leishmaniasis, malaria, and trypanosomiasis. It also discusses the advantages and disadvantages of these applications and their market values and highlights the need for further research in this field.

Glucose-conjugated glutenin nanoparticles for selective targeting and delivery of camptothecin into breast cancer cells

Receptor-mediated drug delivery systems are a promising tool for targeting malignant cells to suppress/inhibit the malignancy without disturbing healthy cells. Protein-based nanocarrier systems possess numerous advantages for the delivery of variety of chemotherapeutics, including therapeutic peptides and genes. In the present work, glucose-conjugated camptothecin-loaded glutenin nanoparticles (Glu-CPT-glutenin NPs) were fabricated to deliver camptothecin to MCF-7 cells via GLUT-1 transporter protein. Initially, Glu-conjugated glutenin polymer was successfully synthesized through reductive amination reaction, and this was confirmed by FTIR and 13C-NMR. Then, camptothecin (CPT) was loaded into Glu-conjugated glutenin polymer forming Glu-CPT-glutenin NPs. The nanoparticles were studied for their drug releasing capacity, morphological shape, size, physical nature, and zeta potential. The fabricated Glu-CPT-glutenin NPs were found to be spherical in shape and amorphous in nature with 200-nm size range and a zeta potential of - 30 mV. Furthermore, MTT assay using Glu-CPT-glutenin NPs confirmed concentration-dependent cytotoxicity against MCF-7 cells after 24-h treatment, and IC50 was found to be 18.23 μg mL-1. In vitro cellular uptake study demonstrated that the Glu-CPT-glutenin NPs had enhanced endocytosis and delivered CPT in MCF-7 cells. A typical apoptotic morphological change of condensed nuclei and distorted membrane bodies was found after treatment with IC50 concentration of NPs. The released CPT from NPs also targeted mitochondria of MCF-7 cells, significantly increasing the level of reactive oxygen species and causing the damage of mitochondrial membrane integrity. These outcomes confirmed that the wheat glutenin can positively serve as a significant delivery vehicle and enhance the anticancer potential of this drug.

Folate receptor targeted NIR cleavable liposomal delivery system augment penetration and therapeutic efficacy in breast cancer

BACKGROUND

Liposomes are predominantly used sorts of nanocarriers for active targeted delivery through surface functionalization using targeting ligand. The folate receptors are overexpressed in various cancers including breast cancer and because of its binding aptitude specifically to folate receptors, folic acid became the attractive ligand.

METHODS

In this research, we have developed a folate and Poly-l-Lysine conjugate and coated this conjugate onto the liposomes. The prepared liposomes were characterized using DLS, FTIR, NMR, SEM, TEM, XRD, AFM, stability and drug release studies. Furthermore, In vitro studies were carried out on FR overexpressed breast cancer cell line.

RESULTS

The FA-LUT-ABC-Lip have diameter of 183 ± 3.17 nm with positive surface charge +33.65 ± 3 mV and the drug release studies confirm the NIR responsive payload cleavage. The coated formulation (in presence of NIR light) effectively reduced the IC₅₀ values and kills breast cancer cells through FR mediated internalization and accelerated drug release. Moreover, LUT Formulation shows anticancer effect due to significant inhibition of cell migration and proliferation by regulating VEGF expression and induced apoptosis through the caspase-3 up-regulation.

CONCLUSION

It is evident from the in vitro studies that the formulation was found to be very effective and can be explored for triggered and targeted delivery of the substances through active targeting.

GENERAL SIGNIFICANCE

Combining receptor mediated drug delivery with triggered release aid in more amounts of drug reaching the target site and achieving enhanced therapeutic activity.

Evolving strategies and application of proteins and peptide therapeutics in cancer treatment

Several proteins and peptides have therapeutic potential and can be used for cancer therapy. By binding to cell surface receptors and other indicators uniquely linked with or overexpressed on tumors compared to healthy tissue, protein biologics enhance the active targeting of cancer cells, as opposed to the passive targeting of cells by conventional small-molecule chemotherapeutics. This study focuses on peptide medications that exist to slow or stop tumor growth and the spread of cancer, demonstrating the therapeutic potential of peptides in cancer treatment. As an alternative to standard chemotherapy, peptides that selectively kill cancer cells while sparing healthy tissue are developing. A mountain of clinical evidence supports the efficacy of peptide-based cancer vaccines. Since a single treatment technique may not be sufficient to produce favourable results in the fight against cancer, combination therapy is emerging as an effective option to generate synergistic benefits. One example of this new area is the use of anticancer peptides in combination with nonpeptidic cytotoxic drugs or the combination of immunotherapy with conventional therapies like radiation and chemotherapy. This review focuses on the different natural and synthetic peptides obtained and researched. Discoveries, manufacture, and modifications of peptide drugs, as well as their contemporary applications, are summarized in this review. We also discuss the benefits and difficulties of potential advances in therapeutic peptides.

Puromycin Prodrug Activation by Thioredoxin Reductase Overcomes Its Promiscuous Cytotoxicity

Overexpression of the selenoprotein thioredoxin reductase (TrxR) has been documented in malignant tissues and is of pathological significance for many types of tumors. The antibiotic puromycin (Puro) is a protein synthesis inhibitor causing premature polypeptide chain termination during translation. The well-defined action mechanism of Puro makes it a useful tool in biomedical studies. However, the nonselective cytotoxicity of Puro limits its therapeutic applications. We report herein the construction and evaluation of two Puro prodrugs, that is, S1-Puro with a five-membered cyclic disulfide trigger and S2-Puro with a linear disulfide trigger. S1-Puro is selectively activated by TrxR and shows the TrxR-dependent cytotoxicity to cancer cells, while S2-Puro is readily activated by thiols. Furthermore, S1-Puro displays higher stability in plasma than S2-Puro. We expect that this prodrug strategy may promote the further development of Puro as a therapeutic agent.

Genetically Encoded Self-Assembling Protein Nanoparticles for the Targeted Delivery In Vitro and In Vivo

Targeted nanoparticles of different origins are considered as new-generation diagnostic and therapeutic tools. However, there are no targeted drug formulations within the composition of nanoparticles approved by the FDA for use in the clinic, which is associated with the insufficient effectiveness of the developed candidates, the difficulties of their biotechnological production, and inadequate batch-to-batch reproducibility. Targeted protein self-assembling nanoparticles circumvent this problem since proteins are encoded in DNA and the final protein product is produced in only one possible way. We believe that the combination of the endless biomedical potential of protein carriers as nanoparticles and the standardized protein purification protocols will make significant progress in "magic bullet" creation possible, bringing modern biomedicine to a new level. In this review, we are focused on the currently existing platforms for targeted self-assembling protein nanoparticles based on transferrin, lactoferrin, casein, lumazine synthase, albumin, ferritin, and encapsulin proteins, as well as on proteins from magnetosomes and virus-like particles. The applications of these self-assembling proteins for targeted delivery in vitro and in vivo are thoroughly discussed, including bioimaging applications and different therapeutic approaches, such as chemotherapy, gene delivery, and photodynamic and photothermal therapy. A critical assessment of these protein platforms' efficacy in biomedicine is provided and possible problems associated with their further development are described.

Light-Triggered Self-Assembly of Peptide Nanoparticles into Nanofibers in Living Cells through Molecular Conformation Changes and H-Bond Interactions

Controlled self-assembly has attracted extensive interest in biological and nanotechnological applications. Enzymatic or biocatalytic triggered self-assembly is widely used for the diagnostic and prognostic marker in different pathologies because of their nanostructures and biological effects. However, it remains a great challenge to control the self-assembly of peptides in living cells with a high degree of spatial and temporal precision. Here we demonstrate a light-triggered platform that enables spatiotemporal control of self-assembly from nanoparticles into nanofibers in living cells through subtle molecular conformational changes and internal H-bonding interactions. The platform contained 3-methylene-2-(quinolin-8-yl) isoindolin-1-one, which acts as the light-controlled unit to disrupt the hydrophilic/lipophilic balance through the change of molecular conformation, and a peptide that can be a faster recombinant to assemble via H-bonding interactions. The process has good biocompatibility because it does not involve waste generation or oxygen consumption; moreover, the assembly rate constant was fast and up to 0.17 min^-1. It is applied to the regulation of molecular assembly in living cells. As such, our findings demonstrate that light-triggered controllable assembly can be applied for initiative regulating cellular behaviors in living systems.

Anticancer therapeutic potential of phosphorylated galactosylated chitosan against N-nitrosodiethyl amine-induced hepatocarcinogenesis

Chitosan is a natural polyfunctional polymer that can be modified to achieve compounds with tailored properties for targeting and treating different cancers. In this study, we report the development and anticancer potential of phosphorylated galactosylated chitosan (PGC). The synthesized compound was characterized by FT-IR, NMR, and mass spectroscopy. The interaction of PGC with asialoglycoprotein receptors (ASGPR) and cellular internalization in HepG2 cells was studied using in silico and uptake studies respectively. PGC was evaluated for its metal chelating, ferric ion reducing, superoxide, and lipid peroxide (LPO) inhibiting potential. Further, anticancer therapeutic potential of PGC was evaluated against N-nitrosodiethylamine (NDEA)-induced hepatocellular carcinoma in a mice model. After development of cancer, PGC was administered to the treatment group (0.5 mg/kg bw, intravenously), once a week for 4 weeks. Characterization studies of PGC revealed successful phosphorylation and galactosylation of chitosan. A strong interaction of PGC with ASGP-receptors was predicted by computational studies and cellular internalization studies demonstrated 98.76 ± 0.53% uptake of PGC in the HepG2 cells. A good metal chelating, ferric ion reducing, and free radical scavenging activity was demonstrated by PGC. The anticancer therapeutic potential of PGC was evident from the observation that PGC treatment increased number of tumor free animals (50%) (6/12) and significantly (p ≤ 0.05) lowered tumor multiplicity as compared to untreated tumor group.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

Boron Nitride Nanoparticles Loaded with a Boron-Based Hybrid as a Promising Drug Carrier System for Alzheimer's Disease Treatment

The search for an innovative and effective drug delivery system that can carry and release targeted drugs with enhanced activity to treat Alzheimer’s disease has received much attention in the last decade. In this study, we first designed a boron-based drug delivery system for effective treatment of AD by integrating the folic acid (FA) functional group into hexagonal boron nitride (hBN) nanoparticles (NPs) through an esterification reaction. The hBN-FA drug carrier system was assembled with a new drug candidate and a novel boron-based hybrid containing an antioxidant as BLA, to constitute a self-assembled AD nano transport system. We performed molecular characterization analyses by using UV-vis spectroscopy, Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS) and Zeta potential investigations. Second, we tested the anti-Alzheimer properties of the carrier system on a differentiated neuroblastoma (SHSY5-Y) cell line, which was exposed to beta-amyloid (1–42) peptides to stimulate an experimental in vitro AD model. Next, we performed cytotoxicity analyses of synthesized molecules on the human dermal fibroblast cell line (HDFa) and the experimental AD model. Cytotoxicity analyses showed that even higher concentrations of the carrier system did not enhance the toxicological outcome in HDFa cells. Drug loading analyses reported that uncoated hBN nano conjugate could not load the BLA, whereas the memantine loading capacity of hBN was 84.3%. On the other hand, memantine and the BLA loading capacity of the hBN-FA construct was found to be 95% and 97.5%, respectively. Finally, we investigated the neuroprotective properties of the nano carrier systems in the experimental AD model. According to the results, 25 µg/mL concentrations of hBN-FA+memantine (94% cell viability) and hBN-FA+BLA (99% cell viability) showed ameliorative properties against beta-amyloid (1–42) peptide toxicity (50% cell viability). These results were generated through the use of flow cytometry, acetylcholinesterase (AChE) and antioxidant assays. In conclusion, the developed drug carrier system for AD treatment showed promising potential for further investigations and enlightened neuroprotective capabilities of boron molecules to treat AD and other neurodegenerative diseases. On the other hand, enzyme activity, systematic toxicity analyses, and animal studies should be performed to understand neuroprotective properties of the designed carrier system comprehensively.

Nanomedicines: A Focus on Nanomaterials as Drug Delivery System with Current Trends and Future Advancement

The rapid advancement of nanomedicine presents novel alternatives that have the potential to transform health care. Targeted drug delivery as well as the synthesis of nanocarriers is a growing discipline that has been intensively researched to reduce the complexity of present medicines in a variety of diseases and to develop new treatment and diagnostic techniques. There are several designed nanomaterials used as a delivery system such as liposomes, micelles, dendrimers, polymers, carbon-based materials, and many other substances, which deliver the drug moiety directly into its targeted body area reducing toxic effect of conventional drug delivery, thus reducing the amount of drug required for therapeutic efficacy and offering many more advantages. Currently, these are used in many applications, including cancer treatment, imaging contrast agents, and biomarker detection and so on. This review provides a comprehensive update in the field of targeted nano-based drug delivery systems, by conducting a thorough examination of the drug synthesis, types, targets, and application of nanomedicines in improving the therapeutic efficiency.

Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment

Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms.

Dynamic covalent chemistry in live cells for organelle targeting and enhanced photodynamic action

Organelle-specific targeting enables increasing the therapeutic index of drugs and localizing probes for better visualization of cellular processes. Current targeting strategies require conjugation of a molecule of interest with organelle-targeting ligands. Here, we propose a concept of dynamic covalent targeting of organelles where the molecule is conjugated with its ligand directly inside live cells through a dynamic covalent bond. For this purpose, we prepared a series of organelle-targeting ligands with a hydrazide residue for reacting with dyes and drugs bearing a ketone group. We show that dynamic hydrazone bond can be formed between these hydrazide ligands and a ketone-functionalized Nile Red dye (NRK) in situ in model lipid membranes or nanoemulsion droplets. Fluorescence imaging in live cells reveals that the targeting hydrazide ligands can induce preferential localization of NRK dye and an anti-cancer drug doxorubicin in plasma membranes, mitochondria and lipid droplets. Thus, with help of the dynamic covalent targeting, it becomes possible to direct a given bioactive molecule to any desired organelle inside the cell without its initial functionalization by the targeting ligand. Localizing the same NRK dye in different organelles by the hydrazide ligands is found to affect drastically its photodynamic activity, with the most pronounced phototoxic effects in mitochondria and plasma membranes. The capacity of this approach to tune biological activity of molecules can improve efficacy of drugs and help to understand better their intracellular mechanisms.

Prodrug based on halloysite delivery systems to improve the antitumor ability of methotrexate in leukemia cell lines

The prodrug approach, as well as the development of specific systems able to deliver a chemotherapeutic agent in the target site, decreasing the side effects often associated with its administration, are still a challenging. In this context, both methotrexate drug molecules (MTX) and biotin ligand moieties, whose receptors are overexpressed on the surface of several cancer cells, were loaded on halloysite nanotubes (HNTs) to develop nanomaterial based on multifunctional and "smart" delivery systems. To highlight the crucial role played by biotin, carrier systems based on HNTs and MTX were also synthetized. In detail, several approaches were envisaged: i) a supramolecular interaction between the clay and the drug; ii) a covalent grafting of the drug onto the HNTs external surface and, iii) a combination of both approaches. The nanomaterials obtained were characterized by thermogravimetric analysis, FT-IR, and UV-vis spectroscopies, DLS and ζ-potential measurements and the morphologies were imaged by HAADF/STEM investigations. Kinetic release experiments at different pH conditions were also performed. Finally, as a proof-of-concept application of our pro-drug delivery systems based on HNTs in cancer therapy, the cytotoxic effects were evaluated on acute myeloid leukemia cell lines, HL60 and its multidrug resistance variant, HL60R. The obtained results showed that both the MTX prodrug system and the biotinylated ones played a crucial role in the biological activity and, they are promising agents for the cancer treatments.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. Reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are currently being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tend to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

PSMA-targeted low-molecular double conjugates for diagnostics and therapy

This review presents data on dual conjugates of therapeutic and diagnostic action for targeted delivery to prostate cancer cells. The works of the last ten years on this topic were analyzed. The mail attention focuses on low-molecular-weight conjugates directed to the prostate-specific membrane antigen (PSMA); the comparison of high and low molecular weight PSMA-targeted conjugates was made. The considered conjugates were divided in the review into two main classes: diagnostic bimodal conjugates (which are containing two fragments for different types of diagnostics), theranostic conjugates (containing both therapeutic and diagnostic agents); also bimodal high molecular weight therapeutic conjugates containing two therapeutic agents are briefly discussed. The data of in vitro and in vivo studies for PSMA-targeted double conjugates available by the beginning of 2021 have been analyzed.

Drug-Free Liposomes Containing Mannosylated Ligand for Liver-Targeting: Synthetic Optimization, Liposomal Preparation, and Bioactivity Evaluation

This research was performed to optimize the enzymatic synthesis of mannosylated ligand with which to prepare mannosy-lated liposomes and investigate their bioactivity. Based on single-factor studies, lipase dose, substrate molar ratio (diester lauric diacid-cholesterol to mannose) and temperature were identified as significant parameters, and optimal reaction conditions were determined through response surface methodology (RSM) with central composite design. The optimum operating parameters, 61.23 mg of lipase, a substrate molar ratio of 5.36, and 56.64 °C temperature offered a predicted yield (71.11%) which was consistent with the actual yield (69.08%). Drug-free mannosylated liposomes were prepared film-dispersion. The characterizations of these liposomes showed that mannosylated liposomes were well-dispersible spherical particles with an average particle size of 142.3 nm, the polydispersity index of 0.16, and a zeta potential of -19.8 mV. Pyrogen examination, hemolytic studies and cytotoxicity assays revealed no substantial safety concern for drug-free mannosylated liposomes. Cellular uptake efficiency of mannosylated liposomes by HepG2 cells was significantly higher than that of unmodified liposomes, demonstrating that mannosylated ligands have a positive effect on liver targeting. Overall, mannosylated liposomes could be active drug delivery system for combatting the therapy of hepatic diseases.

Zwitterion-Based Hydrogen Sulfide Nanomotors Induce Multiple Acidosis in Tumor Cells by Destroying Tumor Metabolic Symbiosis

Destruction of tumor metabolism symbiosis is an attractive cancer treatment method which targets tumor cells with little harm to normal cells. Yet, a single intervention strategy and poor penetration of the drug in tumor tissue result in limited effect. Herein, we propose a zero-waste zwitterion-based hydrogen sulfide (H2 S)-driven nanomotor based on the basic principle of reaction in human body. When loaded with monocarboxylic acid transporter inhibitor α-cyano-4-hydroxycinnamic acid (α-CHCA), the nanomotor can move in tumor microenvironment and induce multiple acidosis of tumor cells and inhibit tumor growth through the synergistic effect of motion effect, driving force H2 S and α-CHCA. Given the good biosafety of the substrate and driving gas of this kind of nanomotor, as well as the limited variety of nanomotors currently available to move in the tumor microenvironment, this kind of nanomotor may provide a competitive candidate for the active drug delivery system of cancer treatment.

Nano Based Approach for the Treatment of Neglected Tropical Diseases

Neglected tropical diseases (NTDs) afflict more than one billion peoples in the world’s poorest countries. The World Health Organization (WHO) has recorded seventeen NTDs in its portfolio, mainly caused by bacterial, protozoal, parasitic, and viral infections. Each of the NTDs has its unique challenges on human health such as interventions for control, prevention, diagnosis, and treatment. Research for the development of new drug molecules against NTDs has not been undertaken by pharmaceutical industries due to high investment and low-returns, which results in limited chemotherapeutics in the market. In addition, conventional chemotherapies for the treatment of NTDs are unsatisfactory due to its low efficacy, increased drug resistance, short half-life, potential or harmful fatal toxic side effects, and drug incompetence to reach the site of parasite infection. In this context, active chemotherapies are considered to be re-formulated by overcoming these toxic side effects via a tissue-specific targeted drug delivery system. This review mainly emphasizes the recent developments of nanomaterial-based drug delivery systems for the effective treatment of NTDs especially sleeping sickness, leishmaniasis, chagas disease, soil-transmitted helminthiasis, african trypanosomiasis and dengue. Nanomaterials based drug delivery systems offer enhanced and effective alternative therapy through the re-formulation approach of conventional drugs into site-specific targeted delivery of drugs.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Molecular Delivery of Cytotoxic Agents via Integrin Activation

Integrins are cell adhesion receptors overexpressed in tumor cells. A direct inhibition of integrins was investigated, but the best inhibitors performed poorly in clinical trials. A gained attention towards these receptors arouse because they could be target for a selective transport of cytotoxic agents. Several active-targeting systems have been developed to use integrins as a selective cell entrance for some antitumor agents. The aim of this review paper is to report on the most recent results on covalent conjugates between integrin ligands and antitumor drugs. Cytotoxic drugs thus conjugated through specific linker to integrin ligands, mainly RGD peptides, demonstrated that the covalent conjugates were more selective against tumor cells and hopefully with fewer side effects than the free drugs.