Nanoscaled poly(L-glutamic acid)/doxorubicin-amphiphile complex as pH-responsive drug delivery system for effective treatment of nonsmall cell lung cancer

Dual-molecular targeting nanomedicine upregulates synergistic therapeutic efficacy in preclinical hepatoma models

Advanced hepatocellular carcinoma (HCC) is one of the most challenging cancers because of its heterogeneous and aggressive nature, precluding the use of curative treatments. Sorafenib (SOR) is the first approved molecular targeting agent against the mitogen-activated protein kinase (MAPK) pathway for the noncurative therapy of advanced HCC; yet, any clinically meaningful benefits from the treatment remain modest, and are accompanied by significant side effects. Here, we hypothesized that using a nanomedicine platform to co-deliver SOR with another molecular targeting drug, metformin (MET), could tackle these issues. A micelle self-assembled with amphiphilic polypeptide methoxy poly(ethylene glycol)-block-poly(L-phenylalanine-co-l-glutamic acid) (mPEG-b-P(LP-co-LG)) (PM) was therefore designed for combinational delivery of two molecular targeted drugs, SOR and MET, to hepatomas. Compared with free drugs, the proposed, dual drug-loaded micelle (PM/SOR+MET) enhanced the drugs' half-life in the bloodstream and drug accumulation at the tumor site, thereby inhibiting tumor growth effectively in the preclinical subcutaneous, orthotopic and patient-derived xenograft hepatoma models without causing significant systemic and organ toxicity. Collectively, these findings demonstrate an effective dual-targeting nanomedicine strategy for treating advanced HCC, which may have a translational potential for cancer therapeutics. STATEMENT OF SIGNIFICANCE: Treatment of advanced hepatocellular carcinoma (HCC) remains a formidable challenge due to its aggressive nature and the limitations inherent to current therapies. Despite advancements in molecular targeted therapies, such as Sorafenib (SOR), their modest clinical benefits coupled with significant adverse effects underscore the urgent need for more efficacious and less toxic treatment modalities. Our research presents a new nanomedicine platform that synergistically combines SOR with metformin within a specialized diblock polypeptide micelle, aiming to enhance therapeutic efficacy while reducing systemic toxicity. This innovative approach not only exhibits marked antitumor efficacy across multiple HCC models but also significantly reduces the toxicity associated with current treatments. Our dual-molecular targeting approach unveils a promising nanomedicine strategy for the molecular treatment of advanced HCC, potentially offering more effective and safer treatment alternatives with significant translational potential.

Heteroatom Doping Promoted Ultrabright and Ultrastable Photoluminescence of Water-Soluble Au/Ag Nanoclusters for Visual and Efficient Drug Delivery to Cancer Cells

Photoluminescence (PL) metal nanoclusters (NCs) have attracted extensive attention due to their excellent physicochemical properties, good biocompatibility, and broad application prospects. However, developing water-soluble PL metal NCs with a high quantum yield (QY) and high stability for visual drug delivery remains a great challenge. Herein, we have synthesized ultrabright l-Arg-ATT-Au/Ag NCs (Au/Ag NCs) with a PL QY as high as 73% and excellent photostability by heteroatom doping and surface rigidization in aqueous solution. The as-prepared Au/Ag NCs can maintain a high QY of over 61% in a wide pH range and various ionic environments as well as a respectable resistance to photobleaching. The results from structure characterization and steady-state and time-resolved spectroscopic analysis reveal that Ag doping into Au NCs not only effectively modifies the electronic structure and photostability but also significantly regulates the interfacial dynamics of the excited states and enhances the PL QY of Au/Ag NCs. Studies in vitro indicate Au/Ag NCs have a high loading capacity and pH-triggered release ability of doxorubicin (DOX) that can be visualized from the quenching and recovery of PL intensity and lifetime. Imaging-guided experiments in cancer cells show that DOX of Au/Ag NCs-DOX agents can be efficiently delivered and released in the nucleus with preferential accumulation in the nucleolus, facilitating deep insight into the drug action sites and pharmacological mechanisms. Moreover, the evaluation of anticancer activity in vivo reveals an outstanding suppression rate of 90.2% for mice tumors. These findings demonstrate Au/Ag NCs to be a superior platform for bioimaging and visual drug delivery in biomedical applications.

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

Facile Synthesis of High Molecular Weight Poly(ethylene glycol)-b-poly(amino acid)s by Relay Polymerization

Poly(amino acid)s (PAAs) are one kind of favorable biopolymer that can be used as a drug or gene carrier. However, conventional ring-opening polymerization of PAAs is slow and needs a strict anhydrous environment with an anhydrous reagent as well as the product without enough high molecular weight (Mn), which limits the expanding of PAAs' application. Herein, we took BLG-NCA as the monomer to quickly synthesize one kind of high Mn amphiphilic copolymer, poly(ethylene glycol)-b-poly(γ-benzyl-l-glutamic acid) (PEG-PBLG), by relay polymerization with a simple one-pot method within 3 h in mild conditions (open air, moisture insensitive). In the polymerization process, ring-opening polymerization-induced self-assembly in sodium bicarbonate aqueous solution first occurred to obtain low Mn PEG-PBLG seeds without purification. Then γ-benzyl-l-glutamate N-carboxyanhydride (BLG-NCA) dichloromethane solution was added into PEG-PBLG seeds directly and stirred vigorously to form am emulsion; during this process, the amphiphilic PEG-PBLG seeds will anchor on the interface of DCM and water to ensure the concentration of α-helix rigid PBLG in DCM to maintain the following relay polymerization. Then, high Mn PEG-PBLG was obtained in mild conditions in one pot. We found that the α-helix rigid structure was essential for relay polymerization by studying the synthetic speed of amphiphilic copolymer with different secondary structures. MOE simulation results showed that PBLG and BLG-NCA tended to form a double hydrogen bond, which was beneficial to relay polymerization because of higher local concentrations that can produce more double hydrogen bonds. Our strategy can quickly obtain high Mn PEG-PBLG (224.9 KDa) within 3 h from PEG-NH2 and BLG-NCA in one pot and did not need an extra initiator. After deprotection, the poly(ethylene glycol)-b-poly(l-glutamate acid) (PEG-PGA) with high Mn as a second product can be used as an excellent antitumor drug carrier. The high Mn PEG-PGA can achieve an encapsulation rate of 86.7% and a drug loading rate of 47.3%, which is twice that of the low Mn PEG-PGA. As a result, the synthesis of PEG-PBLG by relay polymerization simplified the process of PEG-PAA polymerization and increased the Mn. In addition, this method opened a way to obtain other kinds of high Mn PEG-PBLG values in the future.

Poly(Glutamic Acid)-Engineered Nanoplatforms for Enhanced Cancer Phototherapy

Phototherapies, including photothermal therapy and photodynamic therapy, have gained booming development over the past several decades for their attractive non-invasiveness nature, negligible adverse effects, minimal systemic toxicity, and high spatial selectivity. Phototherapy usually requires three components: light irradiation, photosensitizers, and molecular oxygen. Photosensitizers can convert light energy into heat or reactive oxygen species, which can be used in the tumor-killing process. The direct application of photosensitizers in tumor therapy is restricted by their poor water solubility, fast clearance, severe toxicity, and low cellular uptake. The encapsulation of photosensitizers into nanostructures is an attractive strategy to overcome these critical limitations. Poly(glutamic acid) (PGA) is a kind of poly(amino acid)s containing the repeating units of glutamic acid. PGA has superiority for cancer treatment because of its good biocompatibility, low immunogenicity, and modulated pH responsiveness. The hydrophilicity nature of PGA allows the physical entrapment of photosensitizers and anticancer drugs via the construction of amphiphilic polymers. Moreover, the pendent carboxyl groups of PGA enable chemical conjugation with therapeutic agents. In this mini-review, we highlight the stateof- the-art design and fabrication of PGA-based nanoplatforms for phototherapy. We also discuss the potential challenges and future perspectives of phototherapy, and clinical translation of PGA-based nanomedicines.

Tranexamic acid (class I drug) reduced and capped gold nanoparticles as a potential hemostatic agent with enhanced performance

External hemostatic agents play a crucial role in stabilizing an impaired process during pathological conditions. The idea is to stabilize thein vivosystem as soon as possible. This study uses a class I hemostatic drug tranexamic acid as a reducing and capping agent for synthesizing the gold nanoparticles (Tr-AuNPs). Being the synthetic analogue of lysine and a biologically inspired alkylamine molecule, the chemistry can be fine-tuned for stable material that can simultaneously target the intrinsic and extrinsic hemostatic pathway, making it promising for hemostatic applications. The Tr-AuNPs of hydrodynamic diameter ∼46 nm were synthesized and evaluated physio-chemically using various analytical techniques wherein they showed hemocompatibility and increased thrombus weight compared to the native drug. The decrease in prothrombin time (PT) and international normalized ratio supported by the dynamic thromboelastography (TEG) study indicates the prepared nano-conjugate's potential in reducing time for attaining hemostasis as compared to the native tranexamic acid drug. At a 9μg ml-1concentration, Tr-AuNPs had a procoagulant effect, shown by decreased reaction time (R) and coagulation time (K) with improvedαangle and MA. There was a significant increase in the rate of coagulationin vivoby Tr-AuNPs, i.e. (52 s) compared to the native tranexamic acid (360 s). Radiolabelling studies ascertained thein vivobiocompatibility (non-invasive distribution, residence, clearance, and stability) of the Tr-AuNPs. The short-term toxicity studies were conducted to establish a proof of concept for the biomedical application of the material. The results highlighted the use of biologically alkyl amine molecules as capping and reducing agents for the synthesis of nanoparticles, which have shown a synergistic effect on the coagulation cascade while holding the potential for also acting as potential theranostic agents.

Inflammation-responsive drug delivery nanosystems for treatment of bacterial-induced sepsis

Sepsis, a complication of dysregulated host immune systemic response to an infection, is life threatening and causes multiple organ injuries. Sepsis is recognized by WHO as a big contributor to global morbidity and mortality. The heterogeneity in sepsis pathophysiology, antimicrobial resistance threat, the slowdown in the development of antimicrobials, and limitations of conventional dosage forms jeopardize the treatment of sepsis. Drug delivery nanosystems are promising tools to overcome some of these challenges. Among the drug delivery nanosystems, inflammation-responsive nanosystems have attracted considerable interest in sepsis treatment due to their ability to respond to specific stimuli in the sepsis microenvironment to release their payload in a precise, targeted, controlled, and rapid manner compared to non-responsive nanosystems. These nanosystems posit superior therapeutic potential to enhance sepsis treatment. This review critically evaluates the recent advances in the design of drug delivery nanosystems that are inflammation responsive and their potential in enhancing sepsis treatment. The sepsis microenvironment's unique features, such as acidic pH, upregulated receptors, overexpressed enzymes, and enhanced oxidative stress, that form the basis for their design have been adequately discussed. These inflammation-responsive nanosystems have been organized into five classes namely: Receptor-targeted nanosystems, pH-responsive nanosystems, redox-responsive nanosystems, enzyme-responsive nanosystems, and multi-responsive nanosystems. Studies under each class have been thematically grouped and discussed with an emphasis on the polymers used in their design, nanocarriers, key characterization, loaded actives, and key findings on drug release and therapeutic efficacy. Further, this information is concisely summarized into tables and supplemented by inserted figures. Additionally, this review adeptly points out the strengths and limitations of the studies and identifies research avenues that need to be explored. Finally, the challenges and future perspectives on these nanosystems have been thoughtfully highlighted.

An Fc Binding Peptide-Based Facile and Versatile Build Platform for Multispecific Antibodies

Multispecific antibodies (MsAbs) maintain the specificity of versatile antibodies while simultaneously addressing different epitopes for a cumulative, collaborative effect. They could be an alternative treatment to chimeric antigen receptor-T cell therapy by helping to redirect T cells to tumors in vivo. However, one major limitation of their development is their relatively complex production process, which involves performance of a massive screen with low yield, inconsistent quality, and nonnegligible impurities. Here, a poly(l-glutamic acid)-conjugated multiple Fc binding peptide-based synthesis nanoplatform was proposed, in which MsAbs were constructed by mixing the desired monoclonal antibodies (mAbs) with polymeric Fc binding peptides in aqueous solution without purification. To determine its efficacy, a dual immune checkpoint-based PD1/OX40 bispecific antibody and PDL1/CD3e/4-1BB trispecific antibody-based T cell engager were generated to trigger antitumor CD8⁺ T responses in mice, showing superior tumor suppression over free mixed mAbs. In this study, a facile, versatile build platform for MsAbs was established.

Hydrophobic Modification of Poly(γ-glutamic acid) by Grafting 4-Phenyl-butyl Side Groups for the Encapsulation and Release of Doxorubicin

The delivery of drugs is a great challenge, since most of active pharmaceutical ingredients developed today are hydrophobic and poorly water soluble. From this perspective, drug encapsulation on biodegradable and biocompatible polymers can surpass this problem. Poly(γ-glutamic acid) (PGGA), a bioedible and biocompatible polymer has been chosen for this purpose. Carboxylic side groups of PGGA have been partially esterified with 4-phenyl-butyl bromide, producing a series of aliphatic-aromatic ester derivatives with different hydrophilic-lipophilic balances. Using nanoprecipitation or emulsion/evaporation methods, these copolymers were self-assembled in a water solution, forming nanoparticles with average diameters between 89 and 374 nm and zeta potential values between -13.1 and -49.5 mV. The hydrophobic core containing 4-phenyl-butyl side groups was used for the encapsulation of an anticancer drug, such as Doxorubicin (DOX). The highest encapsulation efficiency was reached for a copolymer derived from PGGA, with a 46 mol% degree of esterification. Drug release studies carried out for 5 days at different pHs (4.2 and 7.4) indicated that DOX was released faster at pH 4.2, revealing the potential of these nanoparticles as chemotherapy agents.

Bio-Inspired Drug Delivery Systems: From Synthetic Polypeptide Vesicles to Outer Membrane Vesicles

Nanomedicine is a broad field that focuses on the development of nanocarriers to deliver specific drugs to targeted sites. A synthetic polypeptide is a kind of biomaterial composed of repeating amino acid units that are linked by peptide bonds. The multiplied amphiphilicity segment of the polypeptide could assemble to form polypeptide vesicles (PVs) under suitable conditions. Different from polypeptide vesicles, outer membrane vesicles (OMVs) are spherical buds of the outer membrane filled with periplasmic content, which commonly originate from Gram-negative bacteria. Owing to their biodegradability and excellent biocompatibility, both PVs and OMVs have been utilized as carriers in delivering drugs. In this review, we discuss the recent drug delivery research based on PVs and OMVs. These related topics are presented: (1) a brief introduction to the production methods for PVs and OMVs; (2) a thorough explanation of PV- and OMV-related applications in drug delivery including the vesicle design and biological assessment; (3) finally, we conclude with a discussion on perspectives and future challenges related to the drug delivery systems of PVs and OMVs.

Strong Anionic/Charge-Neutral Block Copolymers from Cu(0)-Mediated Reversible Deactivation Radical Polymerization

Despite recent developments in controlled polymerization techniques, the straightforward synthesis of block copolymers that feature both strong anionic and charge-neutral segments remains a difficult endeavor. In particular, solubility issues may arise during the direct synthesis of strong amphiphiles and typical postpolymerization deprotection often requires harsh conditions. To overcome these challenges, we employed Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-RDRP) on a hydrophobic isobutoxy-protected 3-sulfopropyl acrylate. Cu(0)-RDRP enables the rapid synthesis of the polymer, reaching high conversions and low dispersities while using a single solvent system and low amounts of copper species. These macromolecules are straightforward to characterize and can subsequently be deprotected in a mild yet highly efficient fashion to expose their strongly charged nature. Furthermore, a protected sulfonate segment could be grown from a variety of charge-neutral macroinitiators to produce, after the use of the same deprotection chemistry, a library of amphiphilic, double-hydrophilic as well as thermoresponsive block copolymers (BCPs). The ability of these various BCPs to self-assemble in aqueous media was further studied by dynamic light scattering, ζ-potential measurements as well as atomic force and electron microscopy.

Diselenide-crosslinked carboxymethyl chitosan nanoparticles for doxorubicin delivery: Preparation and in vivo evaluation

In this paper, we report a simple approach to fabricate diselenide-crosslinked carboxymethyl chitosan nanoparticles (DSe-CMC NPs) for doxorubicin (DOX) delivery, with disulfide analogs (DS-CMC NPs) as control. DS-CMC NPs and DSe-CMC NPs featured a spherical morphology and narrow size distribution with the average size about 200 nm. Carboxymethyl chitosan (CMC) as the starting material not only improved the biocompatibility of the nanocarriers but also enhanced physiological stability. Due to electrostatic interactions between DOX and CMC, the nanoparticles had high drug encapsulation efficiency (∼25 %). The nanoparticles disintegration and drug release were accelerated by the cleavage of diselenide bonds through oxidation by H₂O₂ or reduction by GSH. In vitro cell experiments revealed that DOX-loaded DSe-CMC NPs possessed the highest drug accumulation and cytotoxicity in tumor cells. Moreover, DOX-loaded DSe-CMC NPs performed the enhanced growth inhibition in vivo than that of DS-CMC NPs. Thus, the diselenide-crosslinked nanoparticles possess great potentials for DOX delivery.

Facile synthesis of chitosan-based nanogels through photo-crosslinking for doxorubicin delivery

Chitosan-based nanogels are effective carriers for drug delivery due to their biocompatibility and biodegradability. However, the chemically cross-linked nanogels usually require complicated procedures or tough conditions. Herein, we report a simple approach to generate chitosan-based nanogels by photo-crosslinking of poor solvent-induced nanoaggregates without requiring any emulsifying agent, catalyst, or external crosslinker. O-nitrobenzyl alcohol-modified carboxymethyl chitosan was synthesized and self-crosslinked into the nanogels in a mixed solution of ethanol and water under 365 nm light irradiation due to UV-induced primary amine and o-nitrobenzyl alcohol cyclization. The nanogels (CMC-NBA NPs) and lactobionic acid-decorated nanogels (LACMC-NBA NPs) displayed a uniform diameter (~200 nm) and excellent stability under physiological conditions. Notably, the nanogels exhibited a high loading content (~28 %) due to π-π stacking and electrostatic interactions between doxorubicin (DOX) and the carriers. These DOX-loaded nanogels showed rapid drug release under slightly acidic conditions. The cell and animal experiments confirmed that LACMC-NBA NPs increased cellular uptake, improved cytotoxicity in tumor cells, and enhanced growth inhibition in vivo than CMC-NBA NPs. Thus, these photo-crosslinked nanogels possess great potential for DOX delivery.

Synthesis of manganese-incorporated polycaplactone-poly (glyceryl methacrylate) theranostic smart hybrid polymersomes for efficient colon adenocarcinoma treatment

In the current study, a multifunctional nanoscale vesicular system (polymersome) with the ability to accumulate in the site of action, control drug release and integrate diagnostic and therapeutic functions was developed. The theranostic polymersome was engineered as a promising dual-functional nanoplatform, which can be used for tumor therapy and magnetic resonance imaging (MRI). In this regard, the amphiphilic diblock copolymer of poly(ε-caprolactone)-block-poly(glyceryl methacrylate)[(PCL-b-PGMA)] was synthesized by combined ring-opening polymerization (ROP), and reversible addition-fragmentation chain-transfer (RAFT) polymerization techniques followed by hydrolysis of the pendant oxiran rings to hydroxyl groups. Because of the amphiphilic properties and desirable hydrophobic/hydrophilic balance of the synthesized copolymer, it could self-assemble to form a polymersomal structure in an aqueous environment (with diameters about 100 - 145 nm). The hydrophilic anticancer drug, doxorubicin (DOX) and hydrophobic paramagnetic Mn (phenanthroline)₂ complex, being well-represented on T1-weighted magnetic resonance imaging (MRI), were encapsulated in the hydrophilic core (33%±2.3 efficiency) and hydrophobic bilayer membrane (100 %efficient) of a polymersome system, respectively to provide PCL-PGMA@Mn(phen)₂/DOX NPs. It was found that adding aptamer AS1411 to NPs surfaces enhanced their specificity and selectivity towards colorectal cancer cells expressing nucleolin (HT29 and C26). In vivo evaluation after intravenous administration of the prepared platform was performed using subcutaneous C26 tumor-bearing Balb/C mice. The obtained results demonstrated that the prepared targeted platform provided a reduced systemic toxicity in terms of body weight loss and mortality while showing efficient tumor regression. Furthermore, the prepared theranostic platform afforded MRI imaging capability for tumor monitoring. It could be concluded that the biocompatible PCL-PGMA magnetic DOX-loaded polymersomes could serve as a versatile multifunctional system for simultaneous tumor imaging and therapy.

Hybrid Arborescent Polypeptide-Based Unimolecular Micelles: Synthesis, Characterization, and Drug Encapsulation

This paper reports novel hybrid arborescent polypeptides based on poly(γ-benzyl l-glutamate)-co-poly(γ-tert-butyl l-glutamate)-g-polysarcosine [P(BG-co-Glu(OtBu))-g-PSar]. The synthesis is launched by ring-opening polymerization (ROP) of N-carboxyanhydride of γ-benzyl l-glutamate (BG-NCA) and γ-tert-butyl l-glutamate (Glu(OtBu)-NCA) to synthesize a random copolymer P(BG-co-Glu(OtBu)) serving as a precursor for the arborescent system, followed by deprotection of the tert-butyl (tBu) groups to afford free COOH moieties serving as coupling sites. Two copolymerization reactions were carried out to afford the side chains. One type of side chain was a random copolymer P(BG-co-Glu(OtBu)), while the other type was a triblock copolymer PGlu(OtBu)-b-PBG-b-PGlu(OtBu). The peptide coupling reactions were conducted between the COOH moieties on the precursor and the terminus amine on the chain end of the P(BG-co-Glu(OtBu)) random copolymer or the PGlu(OtBu)-b-PBG-b-PGlu(OtBu) triblock copolymer to obtain G0 polymers. Afterward, hydrolyzing the tBu moieties of the G0 substrates yielded randomly functionalized G0 and end-functionalized G0. Randomly functionalized G0 was used as a substrate for the next generation G1 (randomly functionalized and end-functionalized G1 after deprotection) or coated with polysarcosine (PSar) to gain G0-g-PSar. The G0 substrate prepared with the triblock copolymer PGlu(OtBu)-b-PBG-b-PGlu(OtBu) was only grafted with PSar after deprotection, resulting in G0-eg-PSar. Depending on the functionality mode of the G1 substrate, the PSar coating yielded two different graft polymers, G1-g-PSar and G1-eg-PSar, for randomly functionalized and end-functionalized G1, respectively. The PSar hydrophilic shell was decorated with the sequence of (arginine, glycine, and aspartic acid) tripeptides (RGD) as a targeting ligand to improve the potentiality of the arborescent unimolecular micelles as drug carriers. Preparative size exclusion chromatography (SEC) was used to fractionate these complex macromolecular architectures. Nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR), Raman spectroscopy, and SEC were used for molecular characterization of all intermediate and final products and dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) for micellar characterization. A comparison between randomly grafted (g) and end-grafted (eg) unimolecular micelles demonstrates that the former has an undefined core-shell structure, unlike its end-grafted analog. In addition, this study has proved that decoration of the shell with RGD contributed to avoiding micelle aggregation but limited chemotherapy agent encapsulation. However, more than their naked analog, the sustained release was noticeable in decorated micelles. Doxorubicin was utilized as a chemotherapy model, and loading was achieved successfully by physical entrapment.

Recent Advances in Poly(α-L-glutamic acid)-Based Nanomaterials for Drug Delivery

Poly(α-L-glutamic acid) (PGA) is a class of synthetic polypeptides composed of the monomeric unit α-L-glutamic acid. Owing to their biocompatibility, biodegradability, and non-immunogenicity, PGA-based nanomaterials have been elaborately designed for drug delivery systems. Relevant studies including the latest research results on PGA-based nanomaterials for drug delivery have been discussed in this work. The following related topics are summarized as: (1) a brief description of the synthetic strategies of PGAs; (2) an elaborated presentation of the evolving applications of PGA in the areas of drug delivery, including the rational design, precise fabrication, and biological evaluation; (3) a profound discussion on the further development of PGA-based nanomaterials in drug delivery. In summary, the unique structures and superior properties enables PGA-based nanomaterials to represent as an enormous potential in biomaterials-related drug delivery areas.

Recent Advances in Microbial Synthesis of Poly-γ-Glutamic Acid: A Review

Poly-γ-glutamic acid (γ-PGA) is a natural, safe, non-immunogenic, biodegradable, and environmentally friendly glutamic biopolymer. γ-PGA has been regarded as a promising bio-based materials in the food field, medical field, even in environmental engineering field, and other industrial fields. Microbial synthesis is an economical and effective way to synthesize γ-PGA. Bacillus species are the most widely studied producing strains. γ-PGA biosynthesis involves metabolic pathway of racemization, polymerization, transfer, and catabolism. Although microbial synthesis of γ-PGA has already been used extensively, productivity and yield remain the major constraints for its industrial application. Metabolic regulation is an attempt to solve the above bottleneck problems and meet the demands of commercialization. Therefore, it is important to understand critical factors that influence γ-PGA microbial synthesis in depth. This review focuses on production strains, biosynthetic pathway, and metabolic regulation. Moreover, it systematically summarizes the functional properties, purification procedure, and industrial application of γ-PGA.

RETRACTED: mPEG-b-P(Glu-co-Phe) nanoparticles increase gastric retention time and gastric ulcer treatment efficacy of 20(S)-ginsenoside Rg3

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). On behalf of all authors, the corresponding author, Jiannan Li, is retracting the above article. The authors informed the journal that they mistakenly provided inappropriate H&E and EGFR immunohistochemical images for the Rg3-NPs group in Fig. 9 of the published article. The results in Fig. 9D cannot be reproduced as originally published. Importantly, in the present version, Rg3-NPs groups do not show an EGFR promotion effect compared to Rg3 and Cimetidine groups. Therefore, their final results and conclusions are not supported. The authors sincerely apologise to the editors and journal readership for these oversights and inconvenience that this may have caused.

The challenges of controlling polymer synthesis at the molecular and macromolecular level

In this Perspective, we outline advances and challenges in controlling the structure of polymers at various size regimes in the context of structural features such as molecular weight distribution, end groups, architecture, composition and sequence.

Enhanced Doxorubicin Delivery in Folate-Overexpressed Breast Cancer Cells Using Mesoporous Carbon Nanospheres

Nanoparticle-based drug delivery reveals the safety and effectiveness and avoids premature drug release from the nanocarrier. These nanoparticles improve the bioavailability and stability of the drug against chemical and enzymatic degradation and facilitate targeted drug delivery. Herein, targeted folic acid-conjugated oxidized mesoporous carbon nanospheres (Ox-MPCNPs) were successfully fabricated and developed as antitumoral doxorubicin delivery for targeted breast cancer therapy. Fourier transform infrared spectroscopy studies confirmed that the doxorubicin was successfully bound on the Ox-MPCNP through hydrogen bonding and π-π interactions. X-ray diffraction studies showed that the synthesized doxorubicin-loaded Ox-MPCNP is semi-crystalline. The surface morphology of the synthesized doxorubicin-loaded Ox-MPCNP (DOX/Ox-MPCNP-Cys-PAsp-FA) was studied by scanning electron microscopy and high-resolution transmission electron microscopy, which demonstrates a sphere-shaped morphology. The cytotoxic effects of DOX/Ox-MPCNP-Cys-PAsp-FA were studied in MCF-7 breast cancer cells using the CytoTox96 assay kit. The study confirmed the cytotoxic effects of the synthesized nanospheres in vitro. Moreover, DOX/Ox-MPCNP-Cys-PAsp-FA-treated cells displayed efficient cell apoptosis and cell death in flow cytometry analysis. The mitochondrial fragmentation and nucleus damages were further confirmed by fluorescence microscopy. Thus, the approach used to construct the DOX/Ox-MPCNP-Cys-PAsp-FA carrier provides excellent opportunities for the targeted treatment of breast cancer.

Zinc ions coordinated carboxymethyl chitosan-hyaluronic acid microgel for pulmonary drug delivery

Microgel affords a porous and swollen microstructure for the establishment of pulmonary delivery system with sustained released properties. Here, we report a microgel (with the diameter around 4 μm) prepared with a precipitation method, synthesized by coordinating Zn²⁺ to the Schiff base cross-linked carboxymethyl chitosan and glycol split hyaluronate. The microgel has shown well swollen and pH sensitive behaviors, high safety and biocompatibility in vitro. Besides, the biomaterial could escape from macrophage phagocytosis, a key factor contribute to quick drug clearance in the lung after co-incubated with RAW 264.7 cells. In consist with this, the bovine serum albumin loaded in the microgel showed sustained release behavior in 24 h in vitro; meanwhile, the drug had a retention time up to 36 h in the lung and followed by clearance in ICR mice through pulmonary administration. Thus, our microgel platform provides a promising candidate for pulmonary drug delivery systems with controlled release rate.

Co-delivery of gemcitabine and cisplatin via Poly (L-glutamic acid)-g-methoxy poly (ethylene glycol) micelle to improve the in vivo stability and antitumor effect

PURPOSE

The intention of the study was to co-delivery gemcitabine and cisplatin with totally different nature by prodrug and micelle strategy to improve its in vivo stability and antitumor effect.

METHODS

A prodrug of gemcitabine (mPEG-PLG-GEM) was synthesized through the covalent conjugation between the primary amino group of gemcitabine and the carboxylic group of poly (L-glutamic acid)-g-methoxy poly (ethylene glycol) (mPEG-PLG). It was prepared into micelles by a solvent diffusion method, and then combined with cisplatin through chelation to prepare gemcitabine and cisplatin co-loaded mPEG-PLG micelles (mPEG-PLG-GEM@CDDP micelles).

RESULTS

Gemcitabine and cisplatin in each micelle group were released more slowly than in solutions. In addition, pharmacokinetics behaviors of them were improved after encapsulated in prodrug micelles. T_1/2z of gemcitabine and cisplatin encapsulated in micelles were prolonged to 6.357 h (mPEG-PLG-GEM), 10.490 h (mPEG-PLG@CDDP), 5.463 h and 12.540 h (mPEG-PLG-GEM@CDDP) compared with GEM@CDDP solutions (T_1/2z = 1.445 h and 7.740 h). The ratio of synergy between gemcitabine and cisplatin (3:1 ~ 1:1(n/n)) was guaranteed in the systemic circulation, thus improving its antitumor effect. The results of biochemical analysis showed that GEM@CDDP-Sol was more toxic to kidneys and marrow compared with mPEG-PLG-GEM@CDDP micelles.

CONCLUSIONS

By prodrug strategy, gemcitabine and cisplatin with totally different nature were prepared into micelles and obtained a better pharmacokinetic behavior. And the dual drug delivery system performed a better in vivo stability and antitumor effect compared with each single drug delivery system in the experiment. Scheme. Schematic of mPEG-PLG-GEM@CDDP micelles' formation and action process.

Development of an Integrated High Serum Stability Zwitterionic Polypeptide-Based Nanodrug with Both Rapid Internalization and Endocellular Drug Releasing for Efficient Targeted Chemotherapy

Chemotherapeutic nanodrugs have to penetrate through many biological barriers before reaching the tumor cells. Thus, high stability of the nanocarrier before reaching tumor cells and fast release of the carried drugs in targeted tumor cells are required. In this work, inspired by the intrinsic zwitterionic surface property, mainly formed by glutamic acid and lysine residues, of the plasma protein surface, the zwitterionic poly(glutamyl lysine-co-aspartic acid-co-cysteine) peptide (P(EK-D-C)) was synthesized for conjugating n-mercaptoalkanoic acid (MA) with different chain lengths on cysteine residues through a disulfide linkage to load hydrophobic doxorubicin (DOX). The results showed that the slightly negative-biased zwitterionic nanodrugs were very stable in both resistance to nonspecific plasma protein adsorption and prevention of premature DOX release at physiological pH 7.4 due to the zwitterionic polypeptide shell and the sharp contrast in polarity between the shell and DOX-loaded core, while they can quickly release the loaded DOX through responding to both low pH values in the endosome/lysosome and high glutathione concentrations in the tumor cell cytoplasm. Furthermore, the enhanced internalization of these nanodrugs led to about 60% higher in vitro cytotoxicity against MCF-7 cells at pH 6.7 than at pH 7.4, whereas the in vitro cytotoxicity of DOX·HCl at pH 6.7 was only 75% of the value at pH 7.4. In vivo results revealed that the stable nanodrugs conjugated with the long hydrophobic 12-mercaptododecanoic acid had higher tumor inhibition rate and lower systematic toxicity on MCF-7 tumor-bearing mice than the less stable nanodrugs conjugated with the short 8-mercaptooctaoic acid and were significantly superior to DOX·HCl. These results indicate that the combination of high stability in circulation and fast release in tumor cells of nanodrugs can enhance high efficacy targeted chemotherapy. This pH/redox-sensitive zwitterionic polypeptide nanocarrier might provide an excellent vehicle for solid tumor treatment.

Dynamic self-assembly of mannosylated-calix[4]arene into micelles for the delivery of hydrophobic drugs

Carbohydrate-lectin interactions and glycol-molecule-driven self-assembly are powerful yet challenging strategies to create supramolecular nanostructures for biomedical applications. Herein, we develop a modular approach of micellization with a small molecular mannosylated-calix[4]arene synthetic core, CA₄-Man3, to generate nano-micelles, CA₄-Man3-NPs, which can target cancer cell surface receptors and facilitate the delivery of hydrophobic cargo. The oligomeric nature of the calix[4]arene enables the dynamic self-assembly of calix[4]arene (CA₄), where an amphiphile, functionalized with mannose units (CA-glycoconjugates) in the upper rim and alkylated lower rim, afforded the CA₄-Man3-NPs in a controllable manner. The presence of thiourea units between calixarene and tri-mannose moiety facilitated the formation of a stable core with bidentate hydrogen bonds, which in turn promoted mannose receptor targeted uptake and helped in the intracellular pH-responsive release of antineoplastic doxorubicin (Dox). Physiochemical features including the stability of the nanomicelle could circumvent the undesirable leakage of the cargoes, ensuring maximum therapeutic output with minimum off-targeted toxicity. Most importantly, surface-enhanced Raman scattering (SERS) was utilized for the first time to evaluate the critical micelle concentration during the formation, cellular uptake and intracellular drug release. The present study not only provides an architectural design of a new class of organic small molecular nanomicelles but also unveils a robust self-assembly approach that paves the way for the delivery of a wide range of hydrophobic chemotherapeutic drugs.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

Tumor Microenvironment-Responsive Polypeptide Nanogels for Controlled Antitumor Drug Delivery

Tumor microenvironment-responsive polypeptide nanogels belong to a biomaterial with excellent biocompatibility, easily adjustable performance, biodegradability, and non-toxic properties. They are developed for selective delivery of antitumor drugs into target organs to promote tumor cell uptake, which has become an effective measure of tumor treatment. Endogenous (such as reduction, reactive oxygen species, pH, and enzyme) and exogenous (such as light and temperature) responsive nanogels can release drugs in response to tumor tissues or cells to improve drug distribution and reduce drug side effects. This article systematically introduces the research progress in tumor microenvironment-responsive polypeptide nanogels to deliver antitumor drugs and provides a reference for the development of antitumor nanoformulations.

Stimuli-responsive polypeptides for controlled drug delivery

Controlled drug delivery systems, which could release loaded therapeutics upon physicochemical changes imposed by physiological triggers in the desired zone and during the required period of time, offer numerous advantages over traditional drug carriers including enhanced therapeutic effects and reduced toxicity. A polypeptide is a biocompatible and biodegradable polymer, which can be conveniently endowed with stimuli-responsiveness by introducing natural amino acid residues with innate stimuli-responsive characteristics or introducing responsive moieties to its side chains using simple conjugating methods, rendering it an ideal biomedical material for controlled drug delivery. This feature article summarizes our recent work and other relevant studies on the development of polypeptide-based drug delivery systems that respond to single or multiple physiological stimuli (e.g., pH, redox potential, glucose, and hypoxia) for controlled drug delivery applications. The material designs, synthetic strategies, loading and controlled-release mechanisms of drugs, and biomedical applications of these stimuli-responsive polypeptides-based drug delivery systems are elaborated. Finally, the challenges and opportunities in this field are briefly discussed.

Bio-Nanocarriers for Lung Cancer Management: Befriending the Barriers

Lung cancer is a complex thoracic malignancy developing consequential to aberrations in a myriad of molecular and biomolecular signaling pathways. It is one of the most lethal forms of cancers accounting to almost 1.8 million new annual incidences, bearing overall mortality to incidence ratio of 0.87. The dismal prognostic scenario at advanced stages of the disease and metastatic/resistant tumor cell populations stresses the requisite of advanced translational interdisciplinary interventions such as bionanotechnology. This review article deliberates insights and apprehensions on the recent prologue of nanobioengineering and bionanotechnology as an approach for the clinical management of lung cancer. The role of nanobioengineered (bio-nano) tools like bio-nanocarriers and nanobiodevices in secondary prophylaxis, diagnosis, therapeutics, and theranostics for lung cancer management has been discussed. Bioengineered, bioinspired, and biomimetic bio-nanotools of considerate translational value have been reviewed. Perspectives on existent oncostrategies, their critical comparison with bio-nanocarriers, and issues hampering their clinical bench side to bed transformation have also been summarized.

Polypeptide-based drug delivery systems for programmed release

Recent years have seen increasing interests in the use of ring-opening polymerization of α-amino acid N-carboxyanhydrides (NCAs) to prepare synthetic polypeptides, a class of biocompatible and versatile materials, for various biomedical applications. Because of their rich side-chain functionalities, diverse hydrophilicity/hydrophobicity profiles, and the capability of forming stable secondary structures, polypeptides can assemble into a variety of well-organized nano-structures that have unique advantages in drug delivery and controlled release. Herein, we review the design and use of polypeptide-based drug delivery system derived from NCA chemistry, and discuss the future perspectives of this exciting and important biomaterial area that may potentially change the landscape of next-generation therapeutics and diagnosis. Given the high significance of precise control over release for polypeptide-based systems, we specifically focus on the versatile designs of drug delivery systems capable of programmed release, through the changes in the chemical and physical properties controlled by the built-in molecular structures of polypeptides.

PEG-polyaminoacid based micelles for controlled release of doxorubicin: Rational design, safety and efficacy study

A library of amphiphilic monomethoxypolyethylene glycol (mPEG) terminating polyaminoacid co-polymers able to self-assemble into colloidal systems was screened for the delivery and controlled release of doxorubicin (Doxo). mPEG-Glu/Leu random co-polymers were generated by Ring Opening Polymerization from 5 kDa mPEG-NH₂ macroinitiator using 16:0:1, 8:8:1, 6:10:1, 4:12:1 γ-benzyl glutamic acid carboxy anhydride monomer/leucine N-carboxy anhydride monomer/PEG molar ratios. Glutamic acid was selected for chemical conjugation of Doxo, while leucine units were introduced in the composition of the polyaminoacid block as spacer between adjacent glutamic repeating units to minimize the steric hindrance that could impede the Doxo conjugation and to promote the polymer self-assembly by virtue of the aminoacid hydrophobicity. The benzyl ester protecting the γ-carboxyl group of glutamic acid was quantitatively displaced with hydrazine to yield mPEG_5kDa-b-(hydGlu_m-r-Leu_n). Doxo was conjugated to the diblock co-polymers through pH-sensitive hydrazone bond. The Doxo derivatized co-polymers obtained with a 16:0:1, 8:8:1, 6:10:1 Glu/Leu/PEG ratios self-assembled into 30-40 nm spherical nanoparticles with neutral zeta-potential and CMC in the range of 4-7 μM. At pH 5.5, mimicking endosome environment, the carriers containing leucine showed a faster Doxo release than at pH 7.4, mimicking the blood conditions. Doxo-loaded colloidal formulations showed a dose dependent cytotoxicity on two cancer cell lines, CT26 murine colorectal carcinoma and 4T1 murine mammary carcinoma with IC₅₀ slightly higher than those of free Doxo. The carrier assembled with the polymer containing 6:10:1 hydGlu/Leu/PEG molar ratio {mPEG_5kDa-b-[(Doxo-hydGlu)₆-r-Leu₁₀]} was selected for subsequent in vitro and in vivo investigations. Confocal imaging on CT26 cell line showed that intracellular fate of the carrier involves a lysosomal trafficking pathway. The intratumor or intravenous injection to CT26 and 4T1 subcutaneous tumor bearing mice yielded higher antitumor activity compared to free Doxo. Furthermore, mPEG_5kDa-b-[(Doxo-hydGlu)₆-r-Leu₁₀] displayed a better safety profile when compared to commercially available Caelyx®.

PEGylated N-(2 hydroxypropyl) methacrylamide polymeric micelles as nanocarriers for the delivery of doxorubicin in breast cancer

In the present study, polymeric micelles constituted of N-(2-hydroxypropyl)methacrylamide (HPMA) and methoxypoly(ethylene glycol) (mPEG)-based copolymer, mPEG-b-HPMA was studied for the delivery of an anticancer drug, doxorubicin (DOX) by physically loading the drug into its core. A series of mPEG-b-HPMA copolymers of different molecular weights (MWs, ∼4000-25,000 Da) by using various initiator: monomer feed ratios (1:25/75/125/175) were synthesized by radical polymerization technique. The DOX-loaded micelles were prepared at different drug to polymer ratios by thin film hydration method. Block copolymers were structurally characterized by gel permeation chromatography (GPC), ¹H-NMR spectroscopy, fourier transform infrared spectroscopy (FTIR), and critical micelles concentration studies. The DLS and SEM studies indicated that the micelles were spherical with diameters ∼20-100 nm. The DOX-loaded mPEG-b-HPMA micelles, P6-M1, prepared by the polymer synthesized using initiator: monomer feed ratios of 1:175 and at polymer to drug ratios of 10:1 exhibited low particle sizes (∼46.8 nm), highest drug loading and encapsulation efficiencies (5.6 %, and 63.3 %, respectively) compared to the other tested formulations. Confocal microscopy study indicated that the P6-M1 was taken up by breast cancer cell lines, 4T1, MCF-7, and MDA-MB-231in a time-dependent manner. P6-M1 displayed lower half maximal inhibitory concentration (IC₅₀) compared to free drug in all tested treatment durations compared to free DOX. P6-M1 was safe in hemolysis studies with sustained DOX residence in circulation compared to free DOX. The results indicated that mPEG-b-HPMA could be utilized to load DOX effectively, and the optimized nano-micelles, P6-M1 could serve as a promising nanomedicine to treat breast cancer.

Thermo- and ROS-Responsive Self-Assembled Polymer Nanoparticle Tracers for 19F MRI Theranostics

Fluorine-19 magnetic resonance imaging (¹⁹F MRI) enables detailed in vivo tracking of fluorine-containing tracers and is therefore becoming a particularly useful tool in noninvasive medical imaging. In previous studies, we introduced biocompatible polymers based on the hydrophilic monomer N-(2-hydroxypropyl)methacrylamide (HPMA) and the thermoresponsive monomer N-(2,2-difluoroethyl)acrylamide (DFEA). These polymers have abundant magnetically equivalent fluorine atoms and advantageous properties as ¹⁹F MRI tracers. Furthermore, in this pilot study, we modified these polymers by introducing a redox-responsive monomer. As a result, our polymers changed their physicochemical properties once exposed to an oxidative environment. Reactive oxygen species (ROS)-responsive polymers were prepared by incorporating small amounts (0.9-4.5 mol %) of the N-[2-(ferrocenylcarboxamido)ethyl]acrylamide (FcCEA) monomer, which is hydrophobic and diamagnetic in the reduced electroneutral (Fe(II), ferrocene) state but hydrophilic and paramagnetic in the oxidized (Fe(III), ferrocenium cation) state. This property can be useful for theranostic purposes (therapy and diagnostic purposes), especially, in terms of ROS-responsive drug-delivery systems. In the reduced state, these nanoparticles remain self-assembled with the encapsulated drug but release the drug upon oxidation in ROS-rich tumors or inflamed tissues.

pH-Responsive Amphiphilic Polyether Micelles with Superior Stability for Smart Drug Delivery

Despite widespread interest in the amphiphilic polymeric micelles for drug delivery systems, it is highly desirable to achieve high loading capacity and high efficiency to reduce the side effects of therapeutic agents while maximizing their efficacy. Here, we present a novel hydrophobic epoxide monomer, cyclohexyloxy ethyl glycidyl ether (CHGE), containing an acetal group as a pH-responsive cleavable linkage. A series of its homopolymers, poly(cyclohexyloxy ethyl glycidyl ether)s (PCHGEs), and block copolymers, poly(ethylene glycol)-block-poly(cyclohexyloxy ethyl glycidyl ether)s (mPEG-b-PCHGE), were synthesized via anionic ring-opening polymerization in a controlled manner. Subsequently, the self-assembled polymeric micelles of mPEG-b-PCHGE demonstrated high loading capacity, excellent stability in biological media, tunable release efficiency, and high cell viability. Importantly, quantum mechanical calculations performed by considering prolonged hydrolysis of the acetal group in CHGE indicated that the CHGE monomer had higher hydrophobicity than three other functional epoxide monomer analogues developed. Furthermore, the preferential cellular uptake and in vivo therapeutic efficacy confirmed the enhanced stability and the pH-responsive degradation of the amphiphilic block copolymer micelles. This study provides a new platform for the development of versatile smart polymeric drug delivery systems with high loading efficiency and tailorable release profiles.

Engineering of a dual-modal phototherapeutic nanoplatform for single NIR laser-triggered tumor therapy

Theranostic nanoplatforms integrating simultaneously photodynamic therapy (PDT) and photothermal therapy (PTT) exhibit intrinsic advantages in tumor therapy due to distinct mechanisms of action. However, it is challenging to achieve PDT and PTT under single near-infrared (NIR) laser irradiation with a nanoplatform utilizing conventional organic photodynamic agent and inorganic photothermal agent owing to the difference in inherent excitation wavelengths. Particularly, the single NIR light (660 nm)-triggered PTT and PDT nanoplatform, constructed from chlorin e6 (Ce6) and copper sulfide (CuS) nanoparticles (NPs), has never been reported. Herein, we, for the first time, designed and established a dual-modal phototherapeutic nanoplatform that achieved both PTT and PDT under single NIR laser (660 nm) irradiation for Ce6 and CuS NPs with the strategy of core-shell structured CuS@Carbon integrated with Ce6. Introducing of carbon shell not only endows small CuS NPs with excellent tumor accumulation, but also significantly strengthens the photothermal performance of CuS NPs, realizing efficient photothermal performance under 660 nm laser irradiation. Moreover, Ce6 in carbon shell endowed the nanoplatform with photodynamic effect under 660 nm laser irradiation. The as-prepared Ce6/CuS@Carbon nanoplatform thus achieved dual-modal phototherapy under single NIR laser irradiation, significantly inhibiting tumor growth with minimal adverse effects and superior biosafety.

Dermal delivery and follicular targeting of adapalene using PAMAM dendrimers

Acne is a chronic dermatological disease of pilosebaceous units existing in the form of hair follicles (HFs) and accompanying sebaceous glands. In topical acne treatment, localisation of drug substance at the target site, in pilosebaceous units, especially in HFs is essential. The aims of this study were to develop and optimise adapalene (ADA)-loaded PAMAM dendrimer-based nanocarriers for topical acne treatment and to prepare gel formulations of the selected nanocarriers and to characterise their rheological properties and spreadability. ADA accumulation in HFs and in the skin from PAMAM dendrimers' aqueous colloidal formulations and their gel formulations were quantitatively determined using punch biopsy technique. Follicular targeting efficiency from PAMAM dendrimers and their gel formulation was compared with the commercial gel product, Differin^® Gel. The localisation of fluorescently labelled PAMAM dendrimers was visualised using a confocal microscope, which confirmed a successful delivery of the carrier system to the HFs. It was also quantified that PAMAM dendrimers improved follicular localisation and skin deposition of ADA. PAMAM dendrimers' gel formulation including lower ADA doses compared with the commercial product exhibited efficient performance in terms of drug accumulation in HFs. In vitro cell viability studies showed the relative safety of G2-PAMAM dendrimers which could be considered to possibly be well tolerated by the skin. Overall, PAMAM dendrimers' potential to selectively target drugs to the site of action, reduce dose administrated, therefore minimise side effects and provide efficiency in topical treatment of dermatological diseases such as acne was shown.

Polyglutamic acid-based crosslinked doxorubicin nanogels as an anti-metastatic treatment for triple negative breast cancer

Treatment of triple negative breast cancer (TNBC)-associated metastasis represents an unmet clinical need, and we lack effective therapeutics for a disease that exhibits high relapse rates and associates with poor patient outcomes. Advanced nanosized drug delivery systems may enhance the efficacy of first-line chemotherapeutics by altering drug pharmacokinetics and enhancing tumor/metastasis targeting to significantly improve efficacy and safety. Herein, we propose the application of injectable poly-amino acid-based nanogels (NGs) as a versatile hydrophilic drug delivery platform for the treatment of TNBC lung metastasis. We prepared biocompatible and biodegradable cross-linked NGs from polyglutamic acid (PGA) loaded with the chemotherapeutic agent doxorubicin (DOX). Our optimized synthetic procedures generated NGs of ~100 nm in size and 25 wt% drug loading content that became rapidly internalized in TNBC cell lines and displayed IC50 values comparable to the free form of DOX. Importantly, PGA-DOX NGs significantly inhibited lung metastases and almost completely suppressed lymph node metastases in a spontaneously metastatic orthotopic mouse TNBC model. Overall, our newly developed PGA-DOX NGs represent a potentially effective therapeutic strategy for the treatment of TNBC metastases.

Lipidome-based Targeting of STAT3-driven Breast Cancer Cells Using Poly-l-glutamic Acid-coated Layer-by-Layer Nanoparticles

The oncogenic transcription factor STAT3 is aberrantly activated in 70% of breast cancers, including nearly all triple-negative breast cancers (TNBCs). Because STAT3 is difficult to target directly, we considered whether metabolic changes driven by activated STAT3 could provide a therapeutic opportunity. We found that STAT3 prominently modulated several lipid classes, with most profound effects on N-acyl taurine and arachidonic acid, both of which are involved in plasma membrane remodeling. To exploit these metabolic changes therapeutically, we screened a library of layer-by-layer (LbL) nanoparticles (NPs) differing in the surface layer that modulates interactivity with the cell membrane. We found that poly-l-glutamic acid (PLE)-coated NPs bind to STAT3-transformed breast cancer cells with 50% greater efficiency than to nontransformed cells, and the heightened PLE-NP binding to TNBC cells was attenuated by STAT3 inhibition. This effect was also observed in densely packed three-dimensional breast cancer organoids. As STAT3-transformed cells show greater resistance to cytotoxic agents, we evaluated whether enhanced targeted delivery via PLE-NPs would provide a therapeutic advantage. We found that cisplatin-loaded PLE-NPs induced apoptosis of STAT3-driven cells at lower doses compared with both unencapsulated cisplatin and cisplatin-loaded nontargeted NPs. In addition, because radiation is commonly used in breast cancer treatment, and may alter cellular lipid distribution, we analyzed its effect on PLE-NP-cell binding. Irradiation of cells enhanced the STAT3-targeting properties of PLE-NPs in a dose-dependent manner, suggesting potential synergies between these therapeutic modalities. These findings suggest that cellular lipid changes driven by activated STAT3 may be exploited therapeutically using unique LbL NPs.

Magnetic particle targeting for diagnosis and therapy of lung cancers

Over the past decade, the growing interest in targeted lung cancer therapy has guided researchers toward the cutting edge of controlled drug delivery, particularly magnetic particle targeting. Targeting of tissues by magnetic particles has tackled several limitations of traditional drug delivery methods for both cancer detection (e.g., using magnetic resonance imaging) and therapy. Delivery of magnetic particles offers the key advantage of high efficiency in the local deposition of drugs in the target tissue with the least harmful effect on other healthy tissues. This review first overviews clinical aspects of lung morphology and pathogenesis as well as clinical features of lung cancer. It is followed by reviewing the advances in using magnetic particles for diagnosis and therapy of lung cancers: (i) a combination of magnetic particle targeting with MRI imaging for diagnosis and screening of lung cancers, (ii) magnetic drug targeting (MDT) through either intravenous injection and pulmonary delivery for lung cancer therapy, and (iii) computational simulations that models new and effective approaches for magnetic particle drug delivery to the lung, all supporting improved lung cancer treatment. The review further discusses future opportunities to improve the clinical performance of MDT for diagnosis and treatment of lung cancer and highlights clinical therapy application of the MDT as a new horizon to cure with minimal side effects a wide variety of lung diseases and possibly other acute respiratory syndromes (COVID-19, MERS, and SARS).