Shell Cross-Linked Polymeric Micelles as Camptothecin Nanocarriers for Anti-HCV Therapy

Progress in Treatment and Diagnostics of Infectious Disease with Polymers

In this era of advanced technology and innovation, infectious diseases still cause significant morbidity and mortality, which need to be addressed. Despite overwhelming success in the development of vaccines, transmittable diseases such as tuberculosis and AIDS remain unprotected, and the treatment is challenging due to frequent mutations of the pathogens. Formulations of new or existing drugs with polymeric materials have been explored as a promising new approach. Variations in shape, size, surface charge, internal morphology, and functionalization position polymer particles as a revolutionary material in healthcare. Here, an overview is provided of major diseases along with statistics on infection and death rates, focusing on polymer-based treatments and modes of action. Key issues are discussed in this review pertaining to current challenges and future perspectives.

Red blood cell-derived materials for cancer therapy: Construction, distribution, and applications

Cancer has become an increasingly important public health issue owing to its high morbidity and mortality rates. Although traditional treatment methods are relatively effective, they have limitations such as highly toxic side effects, easy drug resistance, and high individual variability. Meanwhile, emerging therapies remain limited, and their actual anti-tumor effects need to be improved. Nanotechnology has received considerable attention for its development and application. In particular, artificial nanocarriers have emerged as a crucial approach for tumor therapy. However, certain deficiencies persist, including immunogenicity, permeability, targeting, and biocompatibility. The application of erythrocyte-derived materials will help overcome the above problems and enhance therapeutic effects. Erythrocyte-derived materials can be acquired via the application of physical and chemical techniques from natural erythrocyte membranes, or through the integration of these membranes with synthetic inner core materials using cell membrane biomimetic technology. Their natural properties such as biocompatibility and long circulation time make them an ideal choice for drug delivery or nanoparticle biocoating. Thus, red blood cell-derived materials are widely used in the field of biomedicine. However, further studies are required to evaluate their efficacy, in vivo metabolism, preparation, design, and clinical translation. Based on the latest research reports, this review summarizes the biology, synthesis, characteristics, and distribution of red blood cell-derived materials. Furthermore, we provide a reference for further research and clinical transformation by comprehensively discussing the applications and technical challenges faced by red blood cell-derived materials in the treatment of malignant tumors.

Medicinal plant molecules against hepatitis C virus: Current status and future prospect

Hepatitis C virus (HCV), a global malady, causes acute and chronic hepatitis leading to permanent liver damage, hepatocellular carcinoma, and death. Modern anti-HCV therapies are efficient, but mostly inaccessible for residents of underdeveloped regions. To innovate more effective treatments at affordable cost, medicinal plant-based products need to be explored. The aim of this article is to review plant constituents in the light of putative anti-HCV mechanisms of action, and discuss existing problems, challenges, and future directions for their potential application in therapeutic settings. One hundred sixty literatures were collected by using appropriate search strings via scientific search engines: Google Scholar, PubMed, ScienceDirect, and Scopus. Bibliography was prepared using Mendeley desktop software. We found a substantial number of plants that were reported to inhibit different stages of HCV life cycle. Traditional medicinal plants such as Phyllanthus amarus Schumach. and Thonn., Eclipta alba (L.) Hassk., and Acacia nilotica (L.) Delile exhibited strong anti-HCV activities. Again, several phytochemicals such as epigallocatechin-3-gallate, honokilol, punicalagin, and quercetin have shown broad-spectrum anti-HCV effect. We have presented promising phytochemicals like silymarin, curcumin, glycyrrhizin, and camptothecin for nanoparticle-based hepatocyte-targeted drug delivery. Nevertheless, only a few animal studies have been performed to validate the anti-HCV effect of these plant products. Again, insufficient clinical evaluation of the safety and effectiveness of herbal medications remain a problem. Selected plants products could be developed as novel therapeutics for HCV patients only after scrupulous evaluation of their safety and efficacy in a clinical set-up.

Nanoscale Interaction Mechanisms of Antiviral Activity

Nanomaterials have now found applications across all segments of society including but not limited to energy, environment, defense, agriculture, purification, food medicine, diagnostics, and others. The pandemic and the vulnerability of humankind to emerging viruses and other infectious diseases has renewed interest in nanoparticles as a potential new class of antivirals. In fact, a growing body of evidence in the literature suggests nanoparticles may have activity against multiple viruses including HIV, HNV, SARS-CoV-2, HBV, HCV, HSV, RSV, and others. The most described antiviral nanoparticles include copper, alloys, and oxides including zinc oxide (ZnO), titanium oxide, iron oxide, and their composites, nitrides, and other ceramic nanoparticles, as well as gold and silver nanoparticles, and sulfated and nonsulfated polysaccharides and other sulfated polymers including galactan, cellulose, polyethylenimine, chitosan/chitin, and others. Nanoparticles, synthesized via the biological or green method, also have great importance and are under major consideration these days, as their method of synthesis is easy, reliable, cost-effective, efficient, and eco-friendly, and is done using easily available sources such as bacteria, actinomycetes, yeast, fungi, algae, herbs, and plants, in comparison to chemically mediated synthesis. Chemical synthesis is highly expensive and involves toxic solvents, high pressure, energy, and high temperature conversion. Examples of biologically synthesized NPs include iron oxide, Cu and CuO NPs, and platinum and palladium NPs. In contrast to traditional medications, nanomedications have multiple advantages: their small size, increased surface to volume ratio, improved pharmacokinetics, improved biodistribution, and targeted delivery. In terms of antiviral activity, nanoscale interactions represent a unique mode of action. As reviewed here their biomedical application as an antiviral has shown four major mechanisms: (1) direct viral interaction prohibiting the virus from infecting the cell, (2) interaction to receptor or cell surface preventing the virus from entering the host cells, (3) preventing the replication of the virus, or (4) other processing mechanisms which inhibit the spread of virus. Here these pharmacologic mechanisms are reviewed and the challenges for technology translation are discussed in more detail.

Nanomedicine based approaches for combating viral infections

Millions of people die each year from viral infections across the globe. There is an urgent need to overcome the existing gap and pitfalls of the current antiviral therapy which include increased dose and dosing frequency, bioavailability challenges, non-specificity, incidences of resistance and so on. These stumbling blocks could be effectively managed by the advent of nanomedicine. Current review emphasizes over an enhanced understanding of how different lipid, polymer and elemental based nanoformulations could be potentially and precisely used to bridle the said drawbacks in antiviral therapy. The dawn of nanotechnology meeting vaccine delivery, role of RNAi therapeutics in antiviral treatment regimen, various regulatory concerns towards clinical translation of nanomedicine along with current trends and implications including unexplored research avenues for advancing the current drug delivery have been discussed in detail.

Combination Chemotherapy with Cisplatin and Chloroquine: Effect of Encapsulation in Micelles Formed by Self-Assembling Hybrid Dendritic-Linear-Dendritic Block Copolymers

Clinical outcomes of conventional drug combinations are not ideal due to high toxicity to healthy tissues. Cisplatin (CDDP) is the standard component for many cancer treatments, yet its principal dose-limiting side effect is nephrotoxicity. Thus, CDDP is commonly used in combination with other drugs, such as the autophagy inhibitor chloroquine (CQ), to enhance tumor cell killing efficacy and prevent the development of chemoresistance. In addition, nanocarrier-based drug delivery systems can overcome chemotherapy limitations, decreasing side effects and increasing tumor accumulation. The aim of this study was to evaluate the toxicity of CQ and CDDP against tumor and non-tumor cells when used in a combined treatment. For this purpose, two types of micelles based on Pluronic^® F127 hybrid dendritic–linear–dendritic block copolymers (HDLDBCs) modified with polyester or poly(esteramide) dendrons derived from 2,2′-bis(hydroxymethyl)propionic acid (HDLDBC-bMPA) or 2,2′-bis(glycyloxymethyl)propionic acid (HDLDBC-bGMPA) were explored as delivery nanocarriers. Our results indicated that the combined treatment with HDLDBC-bMPA(CQ) or HDLDBC-bGMPA(CQ) and CDDP increased cytotoxicity in tumor cells compared to the single treatment with CDDP. Encapsulations demonstrated less short-term cytotoxicity individually or when used in combination compared to the free drugs. However, and more importantly, a low degree of cytotoxicity against non-tumor cells was maintained, even when drugs were given simultaneously.

Janus Dendrimers to Assess the Anti-HCV Activity of Molecules in Cell-Assays

The use of nanocarriers has been revealed as a valid strategy to facilitate drug bioavailability, and this allows for expanding the drug libraries for the treatment of certain diseases such as viral diseases. In the case of Hepatitis C, the compounds iopanoic acid and 3,3',5-triiodothyroacetic acid (or tiratricol) were identified in a primary screening as bioactive allosteric inhibitors of viral NS3 protease, but they did not exhibit accurate activity inhibiting viral replication in cell-based assays. In this work, dendritic nanocarriers are proposed due to their unique properties as drug delivery systems to rescue the bioactivity of these two drugs. Specifically, four different amphiphilic Janus dendrimers synthesized by combining 2,2'-bis(hydroxymethyl)propionic acid (bis-MPA) and 2,2'-bis(glyciloxy)propionic acid (bis-GMPA) functionalized with either hydrophilic or lipophilic moieties at their periphery were used to entrap iopanoic acid and tiratricol. Interestingly, differences were found in the loading efficiencies depending on the dendrimer design, which also led to morphological changes of the resulting dendrimer aggregates. The most remarkable results consist of the increased water solubility of the bioactive compounds within the dendrimers and the improved antiviral activity of some of the dendrimer/drug aggregates, considerably improving antiviral activity in comparison to the free drugs. Moreover, imaging studies have been developed in order to elucidate the mechanism of cellular internalization.

Polymeric micelles for the delivery of poorly soluble drugs: From nanoformulation to clinical approval

Over the last three decades, polymeric micelles have emerged as a highly promising drug delivery platform for therapeutic compounds. Particularly, poorly soluble small molecules with high potency and significant toxicity were encapsulated in polymeric micelles. Polymeric micelles have shown improved pharmacokinetic profiles in preclinical animal models and enhanced efficacy with a superior safety profile for therapeutic drugs. Several polymeric micelle formulations have reached the clinical stage and are either in clinical trials or are approved for human use. This furthers interest in this field and underscores the need for additional learning of how to best design and apply these micellar carriers to improve the clinical outcomes of many drugs. In this review, we provide detailed information on polymeric micelles for the solubilization of poorly soluble small molecules in topics such as the design of block copolymers, experimental and theoretical analysis of drug encapsulation in polymeric micelles, pharmacokinetics of drugs in polymeric micelles, regulatory approval pathways of nanomedicines, and current outcomes from micelle formulations in clinical trials. We aim to describe the latest information on advanced analytical approaches for elucidating molecular interactions within the core of polymeric micelles for effective solubilization as well as for analyzing nanomedicine's pharmacokinetic profiles. Taking into account the considerations described within, academic and industrial researchers can continue to elucidate novel interactions in polymeric micelles and capitalize on their potential as drug delivery vehicles to help improve therapeutic outcomes in systemic delivery.

Advances in Antiviral Material Development

The rise in human pandemics demands prudent approaches in antiviral material development for disease prevention and treatment via effective protective equipment and therapeutic strategy. However, the current state of the antiviral materials research is predominantly aligned towards drug development and its related areas, catering to the field of pharmaceutical technology. This review distinguishes the research advances in terms of innovative materials exhibiting antiviral activities that take advantage of fast-developing nanotechnology and biopolymer technology. Essential concepts of antiviral principles and underlying mechanisms are illustrated, followed with detailed descriptions of novel antiviral materials including inorganic nanomaterials, organic nanomaterials and biopolymers. The biomedical applications of the antiviral materials are also elaborated based on the specific categorization. Challenges and future prospects are discussed to facilitate the research and development of protective solutions and curative treatments.

Micelle carriers based on dendritic macromolecules containing bis-MPA and glycine for antimalarial drug delivery

Biomaterials for antimalarial drug transport still need to be investigated in order to attain nanocarriers that can tackle essential issues related to malaria treatment, e.g. complying with size requirements and targeting specificity for their entry into Plasmodium-infected red blood cells (pRBCs), and limiting premature drug elimination or drug resistance evolution. Two types of dendritic macromolecule that can form vehicles suitable for antimalarial drug transport are herein explored. A new hybrid dendritic-linear-dendritic block copolymer based on Pluronic® F127 and amino terminated 2,2'-bis(glycyloxymethyl)propionic acid dendrons with a poly(ester amide) skeleton (HDLDBC-bGMPA) and an amino terminated dendronized hyperbranched polymer with a polyester skeleton derived from 2,2'-bis(hydroxymethyl)propionic acid (DHP-bMPA) have provided self-assembled and unimolecular micelles. Both types of micelle carrier are biocompatible and exhibit appropriate sizes to enter into pRBCs. Targeting studies have revealed different behaviors for each nanocarrier that may open new perspectives for antimalarial therapeutic approaches. Whereas DHP-bMPA exhibits a clear targeting specificity for pRBCs, HDLDBC-bGMPA is incorporated by all erythrocytes. It has also been observed that DHP-bMPA and HDLDBC-bGMPA incorporate into human umbilical vein endothelial cells with different subcellular localization, i.e. cytosolic and nuclear, respectively. Drug loading capacity and encapsulation efficiencies for the antimalarial compounds chloroquine, primaquine and quinacrine ranging from 30% to 60% have been determined for both carriers. The resulting drug-loaded nanocarriers have been tested for their capacity to inhibit Plasmodium growth in in vitro and in vivo assays.

The synthesis and co-micellization of PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) as shell cross-linked drug carriers with target/redox properties

In order to obtain target/redox shell cross-linked micelles (TCM), copolymers poly(ε-caprolactone)-poly(2-hydroxyethyl methacrylate/methacrylate-alpha lipoic acid) and poly(ε-caprolactone)-poly(2-hydroxyethyl methacrylate/methacrylate-folate, PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) were designed and synthesized. The copolymers PCL-P(HEMA/HEMA-LA) could form reduction-sensitive cross-linked micelles (CM) by using a catalytic amount of DTT. The micelles maintained high stability against dilution but were destroyed in 10 mM dithiothreitol (DTT). The drug loaded content (DLC) of CM was 8.9%, which was almost twice as much as non-cross-linked micelle (NCM). In vitro drug release at pH 7.4 showed that the cumulative release rate of CM in 36 h was less than 30%, while it was about 50% for NCM. When PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) (FA 1%, 3% and 5%) formed target/redox micelles, IC50 of TCM with FA 3% was the lowest (1.4 µg/mL) to Hela cells with excessive expression folate receptors. The cell uptake of TCM by Hela cells is higher than target non-cross-linked micelles (TNCM), while there was not much difference between both micelles uptaken by A549 cells, which are lack of folate receptors. Therefore, the drug carriers of TCM have potential to be explored as shell cross-linked target/redox drug carriers to the cancer cells on the surface with excessive folate receptors.

Cationic poly(ester amide) dendrimers: alluring materials for biomedical applications

Novel cationic poly(ester amide) dendrimers have been synthesized by copper(i) azide-alkyne cycloaddition (CuAAC) of a tripropargylamine core and azide-terminated dendrons, in turn prepared by iterative amide coupling of the new monomer 2,2'-bis(glycyloxymethyl)propionic acid (bis-GMPA). The alternation of ester and amide groups provided a dendritic scaffold that was totally biocompatible and degradable in aqueous media at physiological and acidic pH. The tripodal dendrimers naturally formed rounded aggregates with a drug that exhibited low water solubility, camptothecin, thus improving its cell viability and anti-Hepatitis C virus (anti-HCV) activity. The presence of numerous peripheral cationic groups enabled these dendrimers to form dendriplexes with both pDNA and siRNA and they showed effective in vitro siRNA transfection in tumoral and non-tumoral cell lines.

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.

The role of nanotechnology in the treatment of viral infections

Infectious diseases are the leading cause of mortality worldwide, with viruses in particular making global impact on healthcare and socioeconomic development. In addition, the rapid development of drug resistance to currently available therapies and adverse side effects due to prolonged use is a serious public health concern. The development of novel treatment strategies is therefore required. The interaction of nanostructures with microorganisms is fast-revolutionizing the biomedical field by offering advantages in both diagnostic and therapeutic applications. Nanoparticles offer unique physical properties that have associated benefits for drug delivery. These are predominantly due to the particle size (which affects bioavailability and circulation time), large surface area to volume ratio (enhanced solubility compared to larger particles), tunable surface charge of the particle with the possibility of encapsulation, and large drug payloads that can be accommodated. These properties, which are unlike bulk materials of the same compositions, make nanoparticulate drug delivery systems ideal candidates to explore in order to achieve and/or improve therapeutic effects. This review presents a broad overview of the application of nanosized materials for the treatment of common viral infections.

DNA Transfection to Mesenchymal Stem Cells Using a Novel Type of Pseudodendrimer Based on 2,2-Bis(hydroxymethyl)propionic Acid

In the search for effective vehicles to carry genetic material into cells, we present here new pseudodendrimers that consist of a hyperbranched polyester core surrounded by amino-terminated 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) dendrons. The pseudodendrimers are readily synthesized from commercial hyperbranched bis-MPA polyesters of the second, third, and fourth generations and third-generation bis-MPA dendrons, bearing eight peripheral glycine moieties, coupled by the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). This approach provides globular macromolecular structures bearing 128, 256, and 512 terminal amino groups, and these can complex pDNA. The toxicity of the three pseudodendrimers was studied on two cell lines, mesenchymal stem cells, and HeLa, and it was demonstrated that these compounds do not affect negatively cell viability up to 72 h. The complexation with DNA was investigated in terms of N-to-P ratio and dendriplex stability. The three generations were found to promote internalizing of pDNA into mesenchymal stem cells (MSCs), and their transfection capacity was compared with two nonviral commercial transfection agents, Lipofectamine and TransIT-X2. The highest generations were able to transfect these cells at levels comparable to both commercial reagents.

A shell-crosslinked polymeric micelle system for pH/redox dual stimuli-triggered DOX on-demand release and enhanced antitumor activity

Based on targeted amphiphilic block copolymer N-acetyl glucosamine-poly (styrene-alt-maleic anhydride)₅₈-b-polystyrene₁₃₀ (NAG-P(St-alt-MA)₅₈-b-PSt₁₃₀), a pH/redox dual-triggered shell-crosslinked polymeric micelle system was constructed. The shell-crosslinked micelles (CLM) were prepared by post-crosslinking method to regulate drug release kinetics using cystamine as linkers between carboxy groups of the shell. Compared with non-crosslinked micelles (NCLM), CLM showed spherical shapes with little increased mean diameter of 102.40±0.54nm, low polydispersity index (PDI) of 0.19±0.36, enlarged zeta potential value from -41.46±0.99 to -9.31±0.50mV, indicating the successful modification of disulfide bonds in shell. In vitro drug release study clearly exhibited a pH and redox dual-sensitive drug release profile with significantly accelerated drug release under pH 5.0 and 10mM GSH conditions (46.84% in 96h) without burst release. Both CLM and NCLM showed quite different release profiles between physiological (pH 7.4) and tumoral microenvironment (pH 5.0), effectively avoiding the premature drug leakage and realizing on-demand drug release. The MTT assay implied that CLM presented a time- and concentration-dependent manner to inhibit proliferation of A549 and MCF-7 cells and much lower IC₅₀ values in comparison with that of NCLM after 72h incubation. Both FCM and CLSM results showed that CLM displayed much higher cellular uptake efficiency and anti-tumor activities than NCLM and free DOX. CLM and NCLM could be internalized by energy-dependent endocytosis mechanism due to similar surface properties. Overall, this dual-stimuli triggered micelle system provided a promising tumor-responsive platform for cancer therapy.

Polymeric micelles from block copolymers containing 2,6-diacylaminopyridine units for encapsulation of hydrophobic drugs

New polymers are described that can form micelles in water and can be envisaged as nanocarriers for drug delivery applications.

Crosslinked polymeric self-assemblies as an efficient strategy for photodynamic therapy on a 3D cell culture

Polymeric crosslinked self-assemblies based on poly(ethyleneoxide-b-ε-caprolactone) have been synthesized. They are shown to be more efficient vectors for photodynamic therapy compared to uncrosslinked systems.