Polymer therapeutics as nanomedicines: new perspectives

Preparation of novel sulfated polysaccharide-carboxymethyl-5-fluorouracil-folic acid conjugates for targeted anticancer drug delivery

GFP1, a sulfated polysaccharide extracted from Grateloupia filicina, exhibits remarkable immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), GFP1 was employed as a macromolecular carrier to synthesize of GFP1-C-5-FU by reacting with carboxymethyl-5-fluorouracil (C-5-FU). Subsequently, this new compound was reacted with folic acid (FA) through an ester bond, forming novel conjugates named GFP1-C-5-FU-FA. Nuclear magnetic resonance analysis confirmed the formation of GFP1-C-5-FU-FA. In vitro drug release studies revealed that the cumulative release rate of C-5-FU reached 46.9 % in phosphate buffer (pH 7.4) after 96 h, a rate significantly higher than that of the control groups, indicating the controlled drug release behavior of GFP1-C-5-FU-FA. Additionally, in vitro anticancer assays demonstrated the potent anticancer activity of GFP1-C-5-FU-FA conjugates, as evidenced by the reduced viability of HeLa and AGS cancer cells, along with increased levels of apoptosis and cellular uptake. Western blot analysis indicated that the GFP1-C-5-FU-FA conjugate effectively enhanced phosphorylation in cancer cells through the NF-kB and MAPK pathways, thereby promoting apoptosis. These findings highlight the potential of folate-targeted conjugates in efficiently treating HeLa and AGS cancer cells in vitro and lay a robust theoretical groundwork for future in vivo anti-cancer research involving these cells.

Computational Frontiers in Aptamer-Based Nanomedicine for Precision Therapeutics: A Comprehensive Review

In the rapidly evolving landscape of nanomedicine, aptamers have emerged as powerful molecular tools, demonstrating immense potential in targeted therapeutics, diagnostics, and drug delivery systems. This paper explores the computational features of aptamers in nanomedicine, highlighting their advantages over antibodies, including selectivity, low immunogenicity, and a simple production process. A comprehensive overview of the aptamer development process, specifically the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) process, sheds light on the intricate methodologies behind aptamer selection. The historical evolution of aptamers and their diverse applications in nanomedicine are discussed, emphasizing their pivotal role in targeted drug delivery, precision medicine and therapeutics. Furthermore, we explore the integration of artificial intelligence (AI), machine learning (ML), Internet of Things (IoT), Internet of Medical Things (IoMT), and nanotechnology in aptameric development, illustrating how these cutting-edge technologies are revolutionizing the selection and optimization of aptamers for tailored biomedical applications. This paper also discusses challenges in computational methods for advancing aptamers, including reliable prediction models, extensive data analysis, and multiomics data incorporation. It also addresses ethical concerns and restrictions related to AI and IoT use in aptamer research. The paper examines progress in computer simulations for nanomedicine. By elucidating the importance of aptamers, understanding their superiority over antibodies, and exploring the historical context and challenges, this review serves as a valuable resource for researchers and practitioners aiming to harness the full potential of aptamers in the rapidly evolving field of nanomedicine.

Polyethylene Glycol-Based Polymer-Drug Conjugates: Novel Design and Synthesis Strategies for Enhanced Therapeutic Efficacy and Targeted Drug Delivery

Due to their potential to enhance therapeutic results and enable targeted drug administration, polymer-drug conjugates that use polyethylene glycol (PEG) as both the polymer and the linker for drug conjugation have attracted much research. This study seeks to investigate recent developments in the design and synthesis of PEG-based polymer-drug conjugates, emphasizing fresh ideas that fill in existing knowledge gaps and satisfy the increasing need for more potent drug delivery methods. Through an extensive review of the existing literature, this study identifies key challenges and proposes innovative strategies for future investigations. The paper presents a comprehensive framework for designing and synthesizing PEG-based polymer-drug conjugates, including rational molecular design, linker selection, conjugation methods, and characterization techniques. To further emphasize the importance and adaptability of PEG-based polymer-drug conjugates, prospective applications are highlighted, including cancer treatment, infectious disorders, and chronic ailments.

Prodrug-based nanomedicines for rheumatoid arthritis

Most antirheumatic drugs with high toxicity exhibit a narrow therapeutic window due to their nonspecific distribution in the body, leading to undesirable side effects and reduced patient compliance. To in response to these challenges, prodrug-based nanoparticulate drug delivery systems (PNDDS), which combines prodrug strategy and nanotechnology into a single system, resulting their many advantages, including stability for prodrug structure, the higher drug loading capacity of the system, improving the target activity and bioavailability, and reducing their untoward effects. PNDDS have gained attention as a method for relieving arthralgia syndrome of rheumatoid arthritis in recent years. This article systematically reviews prodrug-based nanocarriers for rheumatism treatment, including Nano systems based on prodrug-encapsulated nanomedicines and conjugate-based nanomedicines. It provides a new direction for the clinical treatment of rheumatoid arthritis.

A comprehensive review on nanocomposite biomaterials based on gelatin for bone tissue engineering

The creation of a suitable scaffold is a crucial step in the process of bone tissue engineering (BTE). The scaffold, acting as an artificial extracellular matrix, plays a significant role in determining the fate of cells by affecting their proliferation and differentiation in BTE. Therefore, careful consideration should be given to the fabrication approach and materials used for scaffold preparation. Natural polypeptides such as gelatin and collagen have been widely used for this purpose. The unique properties of nanoparticles, which vary depending on their size, charge, and physicochemical properties, have demonstrated potential in solving various challenges encountered in BTE. Therefore, nanocomposite biomaterials consisting of polymers and nanoparticles have been extensively used for BTE. Gelatin has also been utilized in combination with other nanomaterials to apply for this purpose. Composites of gelatin with various types of nanoparticles are particularly promising for creating scaffolds with superior biological and physicochemical properties. This review explores the use of nanocomposite biomaterials based on gelatin and various types of nanoparticles together for applications in bone tissue engineering.

High Affinity and FAP-Targeted Radiotracers: A Potential Design Strategy to Improve the Pharmacokinetics and Tumor Uptake for FAP Inhibitors

Fibroblast activation protein (FAP) is overexpressed in cancer-associated fibroblasts, making it an attractive target for both imaging and therapy of malignancy. This study presents a range of novel FAP inhibitors derived from amino derivatives of UAMC1110, incorporating polyethylene glycol and bulky groups containing bifunctional DOTA chelators. The compounds labeled with gallium-68 were developed and characterized to study biodistribution properties and tumor-targeting performance in nude mice bearing U87MG tumor xenografts. Several tracers of interest were screened due to the advantages in imaging and tumor-specific uptake. Positron emission tomography scans revealed that polyethylene glycol-modified ⁶⁸Ga-3-3 had a rapid penetration within the neoplastic tissue and excellent tumor-to-background contrast. In a comparative biodistribution study, naphthalene-modified ⁶⁸Ga-6-3 exhibited more significant tumor uptake (∼50% ID/g, 1 h p.i.) than ⁶⁸Ga-3-3 and 10-fold higher than ⁶⁸Ga-FAPI-04 under the same conditions. Remarkably, ⁶⁸Ga-8-1, combining the two structural design strategies, obtains superior imaging performance.

A novel sulfated mannan-carboxymethyl-5-fluorouracil-folic acid conjugates for targeted anticancer drug delivery

CFP₂ is a sulfated polysaccharide isolated from Codium fragile that shows excellent immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), CFP₂ was used as a macromolecular carrier to react with carboxymethyl-5-fluorouracil (C-5-FU) to form CFP₂-C-5-FU, which further reacted with folic acid (FA) via an ester bond to form novel conjugates (CFP₂-C-5-FU-FA). CFP₂-C-5-FU-FA was confirmed by nuclear magnetic resonance (NMR) analysis. In vitro drug release results showed that the cumulative release rate of C-5-FU was 49.9% in phosphate buffer (pH 7.4) after 96 h, which was much higher than that of the other groups, indicating that CFP2-C-5-FU-FA showed controlled drug release behavior. CFP₂-C-5-FU-FA also exhibited enhanced apoptosis and cellular uptake in vitro. Further, intravenous administration of CFP₂-C-5-FU-FA in an HCT-116 cell-bearing xenograft mouse showed that the conjugates were safe and effective drug delivery systems. These results suggest that folate-targeted conjugates can be used effectively for efficient chemotherapy of colorectal cancer.

Nano Strategies for Artemisinin Derivatives to Enhance Reverse Efficiency of Multidrug Resistance in Breast Cancer

Artemisinin (ART) has been found to exert anti-tumor activity by regulating the cell cycle, inducing apoptosis, inhibiting angiogenesis and tumor invasion and metastasis. Its derivatives (ARTs) can regulate the expression of drug-resistant proteins and reverse the multidrug resistance (MDR) of tumor cells by inhibiting intracellular drug efflux, inducing apoptosis and autophagy of tumor cells, thus enhancing the sensitivity of tumor cells to chemotherapy and radiotherapy. Recent studies have shown that nanodrugs play an important role in the diagnosis and treatment of cancer, which can effectively solve the shortcomings of poor hydrophilicity and low bioavailability of ARTs in the human body, prolong the in vivo circulation time, improve the targeting of drugs (including tumor tissues or specific organelles), and control the release of drugs in target tissues, thereby reducing the side effect. This review systematically summarized the latest research progress of nano-strategies of ARTs to enhance the efficiency of MDR reversal in breast cancer (BC) from the following two aspects: (1) Chemicals encapsulated in nanomaterials based on innovative anti-proliferation mechanism: non-ABC transporter receptor candidate related to ferroptosis (dihydroartemisinin/DHA analogs). (2) Combination therapy strategy of nanomedicine (drug-drug combination therapy, drug-gene combination, and chemical-physical therapy). Self-assembled nano-delivery systems enhance therapeutic efficacy through increased drug loading, rapid reactive release, optimized delivery sequence, and realization of cascade-increasing effects. New nanotechnology methods must be designed for specific delivery routines to achieve targeting administration and overcome MDR without affecting normal cells. The significance of this review is to expect that ART and ARTs can be widely used in clinical practice. In the future, nanotechnology can help people to treat multidrug resistance of breast cancer more accurately and efficiently.

Could the Lung Be a Gateway for Amphotericin B to Attack the Army of Fungi?

Fungal diseases are a significant cause of morbidity and mortality worldwide, primarily affecting immunocompromised patients. Aspergillus, Pneumocystis, and Cryptococcus are opportunistic fungi and may cause severe lung disease. They can develop mechanisms to evade the host immune system and colonize or cause lung disease. Current fungal infection treatments constitute a few classes of antifungal drugs with significant fungi resistance development. Amphotericin B (AmB) has a broad-spectrum antifungal effect with a low incidence of resistance. However, AmB is a highly lipophilic antifungal with low solubility and permeability and is unstable in light, heat, and oxygen. Due to the difficulty of achieving adequate concentrations of AmB in the lung by intravenous administration and seeking to minimize adverse effects, nebulized AmB has been used. The pulmonary pathway has advantages such as its rapid onset of action, low metabolic activity at the site of action, ability to avoid first-pass hepatic metabolism, lower risk of adverse effects, and thin thickness of the alveolar epithelium. This paper presented different strategies for pulmonary AmB delivery, detailing the potential of nanoformulation and hoping to foster research in the field. Our finds indicate that despite an optimistic scenario for the pulmonary formulation of AmB based on the encouraging results discussed here, there is still no product registration on the FDA nor any clinical trial undergoing ClinicalTrial.gov.

Multifunctional Therapeutic Approach of Nanomedicines against Inflammation in Cancer and Aging

Cancer is a fatal disorder that affects people across the globe, yet existing therapeutics are ineffective. The development of submicrometer transport for optimizing the biodistribution of systemically provided medications is the focus of nanomedicine. Nanoparticle- (NP-) based treatments may enable the development of novel therapeutic approaches to combat this deadly disorder. In multifunctional, multimodal imaging, and drug delivery carriers, NPs generally play a major role. They have emerged as potential strategies for the invention of innovative therapeutic procedures in the last decade. The exponential growth of nanotechnologies in recent years has increased public awareness of the application of these innovative therapeutic approaches. Many tumor-targeted nanomedicines have been studied in cancer therapy, and there is clear evidence for a significant improvement in the therapeutic index of antineoplastic drugs. Age-related factors such as metabolic and physiological alterations in old age and inadequate animal models are currently understudied in nanomedicine and pharmacology. This review highlighted the most important targeting approaches, as well as public awareness, therapeutic advancements, and future prospects in age-related metabolic variations, and tumor-targeted nanomedicine studies.

Applications of nanomaterials in tissue engineering

Recent advancement in nanotechnology has brought prominent benefits in tissue engineering, which has been used to repair or reconstruct damaged tissues or organs and design smart drug delivery systems. With numerous applications of nanomaterials in tissue engineering, it is vital to choose appropriate nanomaterials for different tissue engineering applications because of the tissue heterogeneity. Indeed, the use of nanomaterials in tissue engineering is directly determined by the choice. In this review, we mainly introduced the use of nanomaterials in tissue engineering. First, the basic characteristics, preparation and characterization methods of the types of nanomaterials are introduced briefly, followed by a detailed description of the application and research progress of nanomaterials in tissue engineering and drug delivery. Finally, the existing challenges and prospects for future applications of nanomaterials in tissue engineering are discussed.

Scientific description about the types, synthesis, functionalization, characterization application, challenges and prospects of nanomaterials in tissue engineering.

Strategies for the design of nanoparticles: starting with long-circulating nanoparticles, from lab to clinic

Short half-life is one of the main causes of drug attrition in clinical development, which also leads to the failure of many leading compounds and hits to become drug candidates. Nowadays, nanomaterials have been applied to drug development to address this problem. In fact, the clinical application of nanoparticles (NPs) is severely limited due to their rapid elimination by the reticuloendothelial system (RES) in vivo. In this paper, we aim to summarize representative strategies on prolonging the circulation time for bridging the gap between excellent pharmaceutics and proper half-life and encourage clinical translation.

The Tumor Proteolytic Landscape: A Challenging Frontier in Cancer Diagnosis and Therapy

In recent decades, dysregulation of proteases and atypical proteolysis have become increasingly recognized as important hallmarks of cancer, driving community-wide efforts to explore the proteolytic landscape of oncologic disease. With more than 100 proteases currently associated with different aspects of cancer development and progression, there is a clear impetus to harness their potential in the context of oncology. Advances in the protease field have yielded technologies enabling sensitive protease detection in various settings, paving the way towards diagnostic profiling of disease-related protease activity patterns. Methods including activity-based probes and substrates, antibodies, and various nanosystems that generate reporter signals, i.e., for PET or MRI, after interaction with the target protease have shown potential for clinical translation. Nevertheless, these technologies are costly, not easily multiplexed, and require advanced imaging technologies. While the current clinical applications of protease-responsive technologies in oncologic settings are still limited, emerging technologies and protease sensors are poised to enable comprehensive exploration of the tumor proteolytic landscape as a diagnostic and therapeutic frontier. This review aims to give an overview of the most relevant classes of proteases as indicators for tumor diagnosis, current approaches to detect and monitor their activity in vivo, and associated therapeutic applications.

Drug delivery nanosystems targeted to hepatic ischemia and reperfusion injury

Hepatic ischemia and reperfusion injury (IRI) is an acute inflammatory process that results from surgical interventions, such as liver resection surgery or transplantation, or hemorrhagic shock. This pathology has become a severe clinical issue, due to the increasing incidence of hepatic cancer and the high number of liver transplants. So far, an effective treatment has not been implemented in the clinic. Despite its importance, hepatic IRI has not attracted much interest as an inflammatory disease, and only a few reviews addressed it from a therapeutic perspective with drug delivery nanosystems. In the last decades, drug delivery nanosystems have proved to be a major asset in therapy because of their ability to optimize drug delivery, either by passive or active targeting. Passive targeting is achieved through the enhanced permeability and retention (EPR) effect, a main feature in inflammation that allows the accumulation of the nanocarriers in inflammation sites, enabling a higher efficacy of treatment than conventional therapies. These systems also can be actively targeted to specific compounds, such as inflammatory markers and overexpressed receptors in immune system intermediaries, allowing an even more specialized therapy that have already showed encouraging results. In this manuscript, we review drug delivery nanosystems designed for hepatic IRI treatment, addressing their current state in clinical trials, discussing the main hurdles that hinder their successful translation to the market and providing some suggestions that could potentially advance their clinical translation.

Gene Therapy for Drug-Resistant Glioblastoma via Lipid-Polymer Hybrid Nanoparticles Combined with Focused Ultrasound

BACKGROUND

Therapy for glioblastoma (GBM) has always been very challenging, not only because of the presence of the blood-brain barrier (BBB) but also due to susceptibility to drug resistance. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) has revolutionized gene editing technology and is capable of treating a variety of genetic diseases, including human tumors, but there is a lack of safe and effective targeting delivery systems in vivo, especially in the central nervous system (CNS).

METHODS

Lipid-polymer hybrid nanoparticles (LPHNs-cRGD) were constructed for efficient and targeting delivery of CRISPR/Cas9 plasmids targeting O6-methylguanine-DNA methyltransferase (MGMT), a drug-resistance gene to temozolomide (TMZ). Focused ultrasound (FUS)-microbubbles (MBs) were used to non-invasively and locally open the BBB to further facilitate gene delivery into glioblastoma in vivo. The gene editing efficiency and drug sensitivity changes were evaluated both in vitro and in vivo.

RESULTS

The gene-loaded LPHNs-cRGD were successfully synthesized and could protect pCas9/MGMT from enzyme degradation. LPHNs-cRGD could target GBM cells and mediate the transfection of pCas9/MGMT to downregulate the expression of MGMT, resulting in an increased sensitivity of GBM cells to TMZ. MBs-LPHNs-cRGD complexes could safely and locally increase the permeability of the BBB with FUS irradiation in vivo and facilitated the accumulation of nanoparticles at the tumor region in orthotopic tumor-bearing mice. Furthermore, the FUS-assisted MBs-LPHNspCas9/MGMT-cRGD enhanced the therapeutic effects of TMZ in glioblastoma, inhibited tumor growth, and prolonged survival of tumor-bearing mice, with a high level of biosafety.

CONCLUSION

In this work, we constructed LPHNs-cRGD for targeting delivery of the CRISPR/Cas9 system, in combination with FUS-MBs to open the BBB. The MBs-LPHNs-cRGD delivery system could be a potential alternative for efficient targeting gene delivery for the treatment of glioblastoma.

Hydroxyethylcellulose as a methotrexate carrier in anticancer therapy

Clinical and experimental cancer therapy is multifaceted; one such facet is the use of drug carriers. Drug carriers are various nano- and macromolecules, e.g., oligosaccharides, proteins, and liposomes. The present study aimed to verify the suitability of cellulose as a carrier for methotrexate (MTX). Hydroxyethylcellulose, with a molecular weight of 90 kDa and soluble in water, was used. Methotrexate was linked to cellulose by methyl ester bonds. A conjugate containing on average 9.5 molecules of MTX per molecule of cellulose was developed. Gel filtration HPLC analysis showed that the conjugate contained approximately 2% free drug. Dynamic light scattering analysis showed an increase in the polydispersity of the conjugate. The degradation of the conjugate in phosphate buffer and plasma followed first-order kinetics. The conjugate showed the lowest stability (half-life 154 h) in plasma. The conjugate showed 10-fold lower cytotoxicity to the 4 T1 mammary tumour cell line than the free drug. In the in vivo experiment to treat orthotopically implanted mammary tumours, the conjugate and the free drug, both applied intravenously, showed maximum inhibition of tumour growth of 48.4% and 11.2%, respectively. In conclusion, cellulose, which is a non-biodegradable chain glucose polymer, can be successfully used as a drug carrier, which opens up new research perspectives.

Crosslinked polymer nanocapsules for therapeutic, diagnostic, and theranostic applications

Crosslinked polymer nanocapsules (CPNCs) are hollowed nanoparticles with network-like polymeric shells stabilized by primary bonds. CPNCs have drawn broad and significant interests as nanocarriers for biomedical applications in recent years. As compared with conventional polymeric nanoparticles systems without cavity and/or crosslinking architectures, CPNCs possess significant biomedical relevant advantages, including (a) superior structural stability against environmental conditions, (b) high loading capacity and ability for region-specific loading of multiple cargos, (c) tuneable cargo release rate via crosslinking density, and (d) high specific surface area to facilitate surface adsorption, modification, and interactions. With appropriate base polymers and crosslinkages, CPNCs can be biocompatible and biodegradable. While CPNC-based biomedical nanoplatforms can possess relatively stable physicochemical properties owing to their crosslinked architectures, various biomedically relevant stimuli-responsivities can be incorporated with them through specific structural designs. CPNCs have been studied for the delivery of small molecule drugs, genes, proteins, and other therapeutic agents. They have also been investigated as diagnostic platforms for magnetic resonance imaging, ultrasound imaging, and optical imaging. Moreover, CPNCs have been utilized to carry both therapeutics and bioimaging agents for theranostic applications. This article reviews the therapeutic, diagnostic and theranostic applications of CPNCs, as well as the preparation of these CPNCs, reported in the past decade. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Implantable Materials and Surgical Technologies > Nanomaterials and Implants Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Recent Advances and Impact of Chemotherapeutic and Antiangiogenic Nanoformulations for Combination Cancer Therapy

Traditional chemotherapy, along with antiangiogenesis drugs (combination cancer therapy), has shown reduced tumor recurrence and improved antitumor effects, as tumor growth and metastasis are often dependent on tumor vascularization. However, the effect of combination chemotherapy, including synergism and additive and even antagonism effects, depends on drug combinations in an optimized ratio. Hence, nanoformulations are ideal, demonstrating a great potential for the combination therapy of chemo-antiangiogenesis for cancer. The rationale for designing various nanocarriers for combination therapy is derived from organic (polymer, lipid), inorganic, or hybrid materials. In particular, hybrid nanocarriers that consist of more than one material construct provide flexibility for different modes of entrapment within the same carrier—e.g., physical adsorption, encapsulation, and chemical conjugation strategies. These multifunctional nanocarriers can thus be used to co-deliver chemo- and antiangiogenesis drugs with tunable drug release at target sites. Hence, this review attempts to survey the most recent advances in nanoformulations and their impact on cancer treatment in a combined regimen—i.e., conventional cytotoxic and antiangiogenesis agents. The mechanisms and site-specific co-delivery strategies are also discussed herein, along with future prospects.

Recent Advances on Cellulose-Based Nano-Drug Delivery Systems: Design of Prodrugs and Nanoparticles

BACKGROUND

Cellulose being the first abundant biopolymers in nature has many fascinating properties, including low-cost, good biodegradability, and excellent biocompatibility, which made cellulose a real potential material to create nano-drug delivery systems (nano-DDS). This review aims to present and discuss some remarkable recent advances on the drug delivery applications of cellulosebased prodrugs and nanoparticles.

METHODS

By searching the research literatures over last decade, a variety featured studies on cellulosebased nano-DDS were summarized and divided into prodrugs, prodrug nanoparticles, solid or derivative nanopartilces, amphiphilic copolymer nanoparticles, and polyelectrolyte complex nanoparticles. Various methods employed for the functionalization, pharmacodynamic actions and applications were described and discussed.

RESULTS

Many types of cellulose-based nano-DDS can ensure efficient encapsulation of various drugs and then overcome the free drug molecule shortcomings. Among all the method described, cellulosebased amphiphilic nanoparticles are most frequently used. These formulations have the higher drug loading capability, a simple and flexible way to achieve multi-functional. Apart from hydrophilic or hydrophobic modification, cellulose or its derivatives can form nanoparticles with different small molecules and macromolecules, leading to a large spectrum of cellulose-based nano-DDS and providing some unexpected advantages.

CONCLUSION

Thorough physicochemical characterization and profound understanding of interactions of the cellulose-based nano-DDS with cells and tissues is indispensable. Moreover, studies toward technics parameter optimization and scale up from the laboratory to production level should be undertaken. The development of intravenous and orally applicable cellulose-based nano-DDS will be an important research area, and these systems will have more commercial status in the market.

Co-delivery of therapeutic protein and catalase-mimic nanoparticle using a biocompatible nanocarrier for enhanced therapeutic effect

Therapeutic proteins are indispensable in the treatment of various human diseases. Despite the many benefits of therapeutic proteins, they also exhibit diverse side effects. Therefore, reducing unwanted side effects of therapeutic proteins as well as enhancing their therapeutic efficacy are very important in developing therapeutic proteins. Urate oxidase (UOX) is a therapeutic enzyme that catalyzes the conversion of uric acid (UA) into a soluble metabolite, and it is used clinically for the treatment of hyperuricemia. Since UA degradation by UOX generates H₂O₂ (a cytotoxic side product), UOX was co-delivered with catalase-mimic nanoparticles (AuNPs) using biocompatible pluronic-based nanocarriers (NCs) to effectively reduce H₂O₂-associated toxicity in cultured cells and to enhance UA degradation efficiency in vivo. Simple temperature-dependent size changes of NCs allowed co-encapsulation of both UOX and AuNPs at a high loading efficiency without compromising critical properties, resulting in efficient modulation of a mixing ratio of UOX and AuNPs encapsulated in NCs. Co-localizing UOX and AuNPs in the NCs led to enhanced UA degradation and H₂O₂ removal in vitro, leading to a great reduction in H₂O₂-associated cytotoxicity compared with UOX alone or a free mixture of UOX and AuNPs. Furthermore, we demonstrated that co-delivery of UOX and AuNPs using NCs significantly improves in vivo UA degradation compared to simple co-injection of free UOX and AuNPs. More broadly, we showed that biocompatible pluronic-based nanocarriers can be used to deliver a target therapeutic protein along with its toxicity-eliminating agent in order to reduce side effects and enhance efficacy.

Multivalent Inhibitors of Channel-Forming Bacterial Toxins

Rational design of multivalent molecules represents a remarkable modern tool to transform weak non-covalent interactions into strong binding by creating multiple finely-tuned points of contact between multivalent ligands and their supposed multivalent targets. Here, we describe several prominent examples where the multivalent blockers were investigated for their ability to directly obstruct oligomeric channel-forming bacterial exotoxins, such as the pore-forming bacterial toxins and B component of the binary bacterial toxins. We address problems related to the blocker/target symmetry match and nature of the functional groups, as well as chemistry and length of the linkers connecting the functional groups to their multivalent scaffolds. Using the anthrax toxin and AB5 toxin case studies, we briefly review how the oligomeric toxin components can be successfully disabled by the multivalent non-channel-blocking inhibitors, which are based on a variety of multivalent scaffolds.

Stimuli-Responsive Phosphorus-Based Polymers

This microreview details recent developments in stimuli-responsive polymers with phosphorus in the main-chain, in particular polyphosphazenes and polyphosphoesters. The presence of phosphorus in the polymers endows unique properties onto the macromolecules, which can be utilized for the preparation of materials capable of physically responding to specific stimuli. Achieving the desired responsiveness has been much facilitated by recent developments in synthetic polymer chemistry, in particular controlled synthesis and backbone functionalization phosphorus-based polymers, in order to achieve the required properties and hence responsiveness of the materials. The development of phosphorus-based polymers which respond to the most important stimuli are discussed, namely, pH, oxidation, reduction, temperature and biological triggers. The polymers are placed in the context not just of each other but also with reference to state-of-the-art organic polymers.

Can low concentrations of metal oxide and Ag loaded metal oxide nanoparticles pose a risk to stream plant litter microbial decomposers?

Nanoparticles (NPs) continue to be extensively produced by many industries, which ultimately leads to its release into the aquatic environment. It is crucial to estimate the impact of low concentrations of NPs which are environmentally relevant. Litter decomposition is a key ecological process in forested streams; microbes like fungi and bacteria are recognised to play a vital role in litter decomposition. In this study, zinc oxide (ZnO), titanium dioxide (TiO₂), silver loaded ZnO (Ag/ZnO) and silver loaded TiO₂ (Ag/TiO₂) NPs were synthesized, and impacts of low concentrations (0, 2.5, 25, 50 μM) on leaf litter decomposition, fungal sporulation and bacterial growth were assessed. Fungal assemblages consisting of Articulospora tetracladia, Neonectria lugdunensis, Tricladium splendens and Varicosporium elodeae were used to study litter decomposition in microcosms exposed to NPs for 21 days. Two freshwater bacterial species belonging to the family Enterobacteriaceae were used to assess growth after 12 h of exposure to NPs. Types and concentrations of NPs affected litter decomposition and sporulation but not growth of bacteria. Leaf mass loss was significantly different between all concentrations but not between 25 and 50 μM. Fungal sporulation was significantly different among all concentrations of NPs. Fungal sporulation decreased with increase in concentration of NPs whereas a particular trend was not observed with mass loss except for Ag/ZnO. A 50 μM of Ag/ZnO had the highest impact on litter decomposition while 50 μM of ZnO on sporulation. The impact of Ag loaded metal oxides were not strikingly different from those of bare metal oxides except for the more pronounced impact on the mass loss accomplished by Ag/ZnO than by ZnO. Overall our study highlights that very low concentrations of NPs in freshwaters can impact freshwater ecosystem functioning.

A novel nanoformulation of α-eleostearic acid restores molecular pathogenesis of hypersensitivity

AIM

The present work provides first-time empirical and molecular interaction evidence to establish the higher biofunctionality of a therapeutic lipid, α-eleostearic acid (ESA), encapsulated in a novel and thoroughly characterized biocompatible nanoemulsion (NE) system (particle size <200 nm).

MATERIALS & METHODS

A novel methodology was employed to fabricate novel formulations of ESA. Molecular biological tools and assays were used to arrive at definite conclusions.

RESULTS

The proinflammatory profile was found to be significantly mitigated in the hypersensitized rats administered with the ESA-NE formulation more emphatically as compared with ESA-conventional emulsion in both in vivo and ex vivo models.

CONCLUSION

The novel ESA-NE formulation shows a lot of palpable promise for clinical applications.

Nanomedicines for Malaria Chemotherapy: Encapsulation vs. Polymer Therapeutics

Malaria is one of the oldest infectious diseases that afflict humans and its history extends back for millennia. It was once prevalent throughout the globe but today it is mainly endemic to tropical regions like sub-Saharan Africa and South-east Asia. Ironically, treatment for malaria has existed for centuries yet it still exerts an enormous death toll. This contradiction is attributed in part to the rapid development of resistance by the malaria parasite to chemotherapeutic drugs. In turn, resistance has been fuelled by poor patient compliance to the relatively toxic antimalarial drugs. While drug toxicity and poor pharmacological potentials have been addressed or ameliorated with various nanomedicine drug delivery systems in diseases like cancer, no clinically significant success story has been reported for malaria. There have been several reviews on the application of nanomedicine technologies, especially drug encapsulation, to malaria treatment. Here we extend the scope of the collation of the nanomedicine research literature to polymer therapeutics technology. We first discuss the history of the disease and how a flurry of scientific breakthroughs in the latter part of the nineteenth century provided scientific understanding of the disease. This is followed by a review of the disease biology and the major antimalarial chemotherapy. The achievements of nanomedicine in cancer and other infectious diseases are discussed to draw parallels with malaria. A review of the current state of the research into malaria nanomedicines, both encapsulation and polymer therapeutics polymer-drug conjugation technologies, is covered and we conclude with a consideration of the opportunities and challenges offered by both technologies.

Particle-Stabilized Fluid-Fluid Interfaces: The Impact of Core Composition on Interfacial Structure

The encapsulation of small molecule drugs in nanomaterials has become an increasingly popular approach to the delivery of therapeutics. The use of emulsions as templates for the synthesis of drug impregnated nanomaterials is an exciting area of research, and a great deal of progress has been made in understanding the interfacial chemistry that is critical to controlling the physicochemical properties of both the encapsulated material and the templated material. For example, control of the interfacial tension between an oil and aqueous phase is a fundamental concern when designing drug delivery vehicles that are stabilized by particulate surfactants at the fluid interface. Particles in general are capable of self-assembly at a fluid interface, with a preference for one or the other of the phases, and much work has focussed on modification of the particle properties to optimize formation and stability of the emulsion. An issue arises however when a model, single oil system is translated into more complex, real-world scenarios, which are often multi-component, with the incorporation of charged active ingredients and other excipients. The result is potentially a huge change in the properties of the dispersed phase which can lead to a failure in the capability of particles to continue to stabilize the interface. In this mini-review, we will focus on two encapsulation strategies based on the selective deposition of particles or proteins on a fluid-fluid interface: virus-like particles and polymer microcapsules formed from particle-stabilized emulsion templates. The similarity between these colloidal systems lies in the fact that particulate entities are used to stabilize fluid cores. We will focus on those studies that have described the effect of subtle changes in core composition on the self-assembly of particles at the fluid-fluid interface and how this influences the resulting capsule structure.

Promising nanotherapy in treating leishmaniasis

Leishmaniases are infectious diseases caused by an intracellular protozoan in humans by 20 different species of Leishmania among more than 53 species. There are at least twelve million cases of infections worldwide and three hundred and fifty million people are at risk in at least 98 developing countries in Africa, South-East Asia, and the Americas. Only Brazil presented high burden for both visceral leishmaniasis (VL) and cutaneous (CL). Chemotherapy is the main means of dealing with this infection. Nevertheless, only a few effective drugs are available, and each has a particular disadvantage; toxicity and long-term regimens compromise most chemotherapeutic options, which decreases patient compliance and adherence to the treatment and consequently the emergence of drug-resistant strains. Nano drug delivery systems (NanoDDS) can direct antileishmanial drug substances for intracellular localization in macrophage-rich organs such as bone marrow, liver, and spleen. This strategy can improve the therapeutic efficacy and reduce the toxic effects of several antileishmanial drug substances. This review is an effort to comprehensively compile recent findings, with the aim of advancing understanding of the importance of nanotechnology for treating leishmaniases.

Preparation and Characterization of Electrostatically Crosslinked Polymer⁻Liposomes in Anticancer Therapy

pH-sensitive polymer⁻liposomes can rapidly release their payloads. However, it is difficult to simultaneously achieve stability and pH-responsiveness in the polymer⁻liposomes. In this study, stable and pH-sensitive crosslinked polymer⁻liposomes were fabricated through electrostatic interactions. The pH-sensitive copolymer methoxy poly(ethylene glycol)-block-poly(methacrylic acid)-cholesterol (mPEG-b-P(MAAc)-chol) and crosslinking reagent poly(ethylene glycol) with end-capped with lysine (PEG-Lys2) were synthesized and characterized. At physiological conditions, the pH-sensitive copolymers were anionic and interacted electrostatically with the cationic crosslinker PEG-Lys2, forming the electrostatically-crosslinked polymer⁻liposomes and stabilizing the liposomal structure. At pH 5.0, the carboxylic groups in mPEG-b-P(MAAc)-chol were neutralized, and the liposomal structure was destroyed. The particle size of the crosslinked polymer⁻liposomes was approximately 140 nm and the polymer⁻liposomes were loaded with the anticancer drug doxorubicin. At pH 7.4, the crosslinked polymer⁻liposomes exhibited good stability with steady particle size and low drug leakage, even in the presence of fetal bovine serum. At pH 5.0, the architecture of the crosslinked polymer⁻liposomes was damaged following rapid drug release, as observed by using transmission electron microscopy and their apparent size variation. The crosslinked polymer⁻liposomes were pH-sensitive within the endosome and in the human breast cancer cells MDA-MB-231, as determined by using confocal laser scanning microscopy. The intracellular drug release profiles indicated cytotoxicity in cancer cells. These results indicated that the highly-stable and pH-sensitive electrostatically-crosslinked polymer⁻liposomes offered a potent drug-delivery system for use in anticancer therapies.

Polymeric therapeutic delivery systems for the treatment of infectious diseases

Infectious diseases caused by germs, parasites, fungi, virus and bacteria are one of the leading causes of death worldwide. Polymeric therapeutics are nanomedicines that offer several advantages making them useful for the treatment of infectious diseases such as targeted drug release mechanism, ability to maintain the drug concentration within a therapeutic window for a desired duration, biocompatibility with low immunogenicity and reduced drug toxicity resulting in enhanced therapeutic efficacy of the incorporated drug. Although polymeric therapeutics have been evaluated for the treatment of infectious diseases in vitro and in vivo with improved therapeutic efficacy, most treatments for infectious disease have not been evaluated using polymeric therapeutics. This review will focus on the applications of polymeric therapeutics for the treatment of infectious diseases (preclinical studies and clinical trials), with particular focus on parasitic and viral infections.

Molecular Consortia-Various Structural and Synthetic Concepts for More Effective Therapeutics Synthesis

The design and discovery of novel drug candidates are the initial and most probably the crucial steps in the drug development process. One of the tasks of medicinal chemistry is to produce new molecules that have a desired biological effect. However, even today the search for new pharmaceuticals is a very complicated process that is hard to rationalize. Literature provides many scientific reports on future prospects of design of potentially useful drugs. Many trends have been proposed for the design of new drugs containing different structures (dimers, heterodimers, heteromers, adducts, associates, complexes, biooligomers, dendrimers, dual-, bivalent-, multifunction drugs and codrugs, identical or non-identical twin drugs, mixed or combo drugs, supramolecular particles and various nanoindividuals. Recently much attention has been paid to different strategies of molecular hybridization. In this paper, various molecular combinations were described e.g., drug–drug or drug-non-drug combinations which are expressed in a schematic multi-factor form called a molecular matrix, consisting of four factors: association mode, connection method, and the number of elements and linkers. One of the most popular trends is to create small–small molecule combinations such as different hybrids, codrugs, drug–drug conjugates (DDCs) and small-large molecule combinations such as antibody-drug conjugates (ADCs), polymer-drug conjugates (PDCs) or different prodrugs and macromolecular therapeutics. A review of the structural possibilities of active framework combinations indicates that a wide range of potentially effective novel-type compounds can be formed. What is particularly important is that new therapeutics can be obtained in fast, efficient, and selective methods using current trends in chemical synthesis and the design of drugs such as the “Lego” concept or rational green approach.

Magnetic iron oxide nanoparticles as drug carriers: clinical relevance

Significant preclinical and clinical research has explored the use of magnetic iron oxide nanoparticles (MNPs) for medical theranostics. Herein, we provide an overview of the optimal ‘design-to-perform’ MNPs used in cancer therapeutics, specifically focusing on magnetic hyperthermia, magnetic drug targeting, and targeting delivery. An account of the progress made in the clinic using MNPs is then analyzed. We place special emphasis on past and present magnetic nanoformulations used in clinical settings or yet to be clinically approved. Regrettably, as of now, no MNP drug delivery system is employed in the clinic. Thus, identifying current limitations, misconceptions and challenges will definitely impact the clinical success of MNP delivery theranostic systems and their promising future potential in medicine.

New utilization of Polygonum multiflorum polysaccharide as macromolecular carrier of 5-fluorouracil for controlled release and immunoprotection

WPMP-2 is an acid polysaccharide isolated from Polygonum multiflorum, which demonstrated excellent immunomodulatory activity. In order to reduce immunosuppression of 5-fluorouracil (5-Fu), WPMP-2 was utilized as a macromolecular carrier to conjugate the 5-Fu derivatives 5-fluorouracil-1-acetic acid (5-FUAC) through ester bond. The conjugate showed controlled drug release behaviour in vitro at 37°C in phosphate buffer (pH7.4), and only 5-FUAC was detected in the media. The cytotoxicity test in vitro showed that the conjugate exhibited different cytotoxicity to HepG-2 and HT-29 cells. In addition, immunization study in vivo illustrated that the conjugate displayed immunoprotective effect by mitigating inhibition and damage effects of 5-Fu on secretion of cytokines, proliferation of splenocytes, and phagocytosis of peritoneal macrophages. It was indicated that the conjugation of 5-Fu and WPMP-2 could be a potential double effective drug delivery system.

Site-Specific DBCO Modification of DEC205 Antibody for Polymer Conjugation

The design of multifunctional polymer-based vectors, forming pDNA vaccines, offers great potential in cancer immune therapy. The transfection of dendritic immune cells (DCs) with tumour antigen-encoding pDNA leads to an activation of the immune system to combat tumour cells. In this work, we investigated the chemical attachment of DEC205 antibodies (aDEC205) as DC-targeting structures to polyplexes of P(Lys)-b-P(HPMA). The conjugation of a synthetic block copolymer and a biomacromolecule with various functionalities (aDEC205) requires bioorthogonal techniques to avoid side reactions. Click chemistry and in particular the strain-promoted alkyne-azide cycloaddition (SPAAC) can provide the required bioorthogonality. With regard to a SPAAC of both components, we firstly synthesized two different azide-containing block copolymers, P(Lys)-b-P(HPMA)-N₃(stat) and P(Lys)-b-P(HPMA)-N₃(end), for pDNA complexation. In addition, the site-specific incorporation of ring-strained dibenzocyclooctyne (DBCO) moieties to the DEC205 antibody was achieved by an enzymatic strategy using bacterial transglutaminase (BTG). The chemical accessibility of DBCO molecules within aDEC205 as well as the accessibility of azide-functionalities on the polyplex' surface were investigated by various SPAAC experiments and characterized by fluorescence correlation spectroscopy (FCS).

A New Co-P Nanocomposite with Ultrahigh Relaxivity for In Vivo Magnetic Resonance Imaging-Guided Tumor Eradication by Chemo/Photothermal Synergistic Therapy

Design of new nanoagents that intrinsically have both diagnostic imaging and therapeutic capabilities is highly desirable for personalized medicine. In this work, a novel nanotheranostic agent is fabricated based on polydopamine (PDA)-functionalized Co-P nanocomposites (Co-P@PDA) for magnetic resonance imaging (MRI)-guided combined photothermal therapy and chemotherapy. The ultrahigh relaxivity of 224.61 mm^-1 s^-1 can enable Co-P@PDA to be applied as an excellent contrast agent for MRI in vitro and in vivo, providing essential and comprehensive information for tumor clinical diagnosis. Moreover, Co-P@PDA exhibit excellent photothermal performance owing to the strong near-infrared (NIR) absorbance of both Co-P nanocomposite and PDA. Highly effective ablation of tumors is achieved in a murine tumor model because the NIR laser not only induces photothermal effects but also triggers the chemotherapeutic drug on-demand release, which endows the Co-P@PDA with high curative effects but little toxicity and few side effects. These findings demonstrate that Co-P@PDA are promising agents for highly effective and precise antitumor treatment and warrant exploration as novel theranostic nanoagents with good potential for future clinical translation.

Construction of a hypoxia responsive upconversion nanosensor for tumor imaging by fluorescence resonance energy transfer from carbon dots to ruthenium complex

Hypoxia responsive upconversion nano-aggregates are synthesized which can be excited by NIR light to give oxygen dependent phosphorescence emission via the FRET process.

Potential applications and human biosafety of nanomaterials used in nanomedicine

With the rapid development of nanotechnology, potential applications of nanomaterials in medicine have been widely researched in recent years. Nanomaterials themselves can be used as image agents or therapeutic drugs, and for drug and gene delivery, biological devices, nanoelectronic biosensors or molecular nanotechnology. As the composition, morphology, chemical properties, implant sites as well as potential applications become more and more complex, human biosafety of nanomaterials for clinical use has become a major concern. If nanoparticles accumulate in the human body or interact with the body molecules or chemical components, health risks may also occur. Accordingly, the unique chemical and physical properties, potential applications in medical fields, as well as human biosafety in clinical trials are reviewed in this study. Finally, this article tries to give some suggestions for future work in nanomedicine research. Copyright © 2017 John Wiley & Sons, Ltd.

Inhibit or Evade Multidrug Resistance P-Glycoprotein in Cancer Treatment

Multidrug resistance (MDR) is a major cause of failure in cancer chemotherapy. P-glycoprotein (P-gp), a promiscuous drug efflux pump, has been extensively studied for its association with MDR due to overexpression in cancer cells. Several P-gp inhibitors or modulators have been investigated in clinical trials in hope of circumventing MDR, with only limited success. Alternative strategies are actively pursued, such as the modification of existing drugs, development of new drugs, or combination of novel drug delivery agents to evade P-gp-dependent efflux. Despite the importance and numerous studies, these efforts have mostly been undertaken without a priori knowledge of how drugs interact with P-gp at the molecular level. This review highlights and discusses progress toward and challenges impeding drug development for inhibiting or evading P-gp in the context of our improved understanding of the structural basis and mechanism of P-gp-mediated MDR.

A pH-sensitive Macromolecular Prodrug as TLR7/8 Targeting Immune Response Modifier

The chemical synthesis and biological activity of novel functionalized imidazoquinoline derivatives (ImQ) to generate Toll-like receptor (TLR) 7/8 specific prodrugs are presented. In vivo activity of ImQs to induce inflammation was confirmed in zebrafish larvae. After covalent ligation to fully biodegradable polyphosphazenes (ImQ-polymer), the macromolecular prodrugs were designed to undergo intracellular pH-sensitive release of ImQs to induce inflammation through binding to endosomal TLR7/8 (danger signal). We showed ImQ dissociation from prodrugs at a pH 5 pointing towards endosomal prodrug degradability. ImQ-polymers strongly activated ovalbumin-specific T cells in murine splenocytes as shown by increased proliferation and expression of the IL-2 receptor (CD25) on CD8+ T cells accompanied by strong IFN-γ release. ImQ prodrugs presented here are suggested to form the basis of novel nanovaccines, for example, for intravenous or intratumoral cancer immunotherapeutic applications to trigger physiological antitumor immune responses.

Polymer therapeutics at a crossroads? Finding the path for improved translation in the twenty-first century

Despite the relatively small early investment, first generation 'polymer therapeutics' have been remarkably successful with more than 25 products licenced for human use as polymeric drugs, sequestrants, conjugates, and as an imaging agent. Many exhibit both clinical and commercial success with new concepts already in clinical trials. Nevertheless after four decades of evolution, this field is arriving at an important crossroads. Over the last decade, the landscape has changed rapidly. There are an increasing number of failed clinical trials, the number of 'copy' and 'generic' products is growing (danger of ignoring the biological rationale for design and suppression of innovation), potential drawbacks of PEG are becoming more evident, and the 'nanomedicine' boom has brought danger of loss of scientific focus/hype. Grasping opportunities provided by advances in understanding of the patho-physiology and molecular basis of diseases, new polymer/conjugate synthetic and analytical methods, as well as the large database of clinical experience will surely ensure a successful future for innovative polymer therapeutics. Progress will, however, be in jeopardy if polymer safety is overlooked in respect of the specific route of administration/clinical use, poorly characterised materials/formulations are used to define biological or early clinical properties, and if clinical trial protocols fail to select patients most likely to benefit from these macromolecular therapeutics. Opportunities to improve clinical trial design for polymer-anticancer drug conjugates are discussed. This short personal perspective summarises some of the important challenges facing polymer therapeutics in R&D today, and future opportunities to improve successful translation.