Rational Design of Polymeric Nanoparticles with Tailorable Biomedical Functions for Cancer Therapy

The Discovery of Novel Antimicrobial Agents through the Application of Isocyanide-Based Multicomponent Reactions

Multicomponent reactions (MCR) have been used to synthesize a wide range of analogs from several classes of heterocyclic compounds, with multifaceted medicinal uses. The synthesis of highly functionalized molecules in a single pot is a unique property of MCR, allowing researchers to quickly assemble libraries of compounds of biological interest and uncover novel leads as possible therapeutic agents. Isocyanide-based multicomponent reactions have proven to be extremely effective at swiftly specifying members of compound libraries, particularly in the discovery of drugs. The understanding of structure-activity correlations that drive the development of new goods and technology requires structural variety in these libraries. In today's world, antibiotic resistance is a major ongoing problem that poses risks to public health. The implementation of isocyanide-based multicomponent reactions upholds a significant potential in this regard. By utilizing such reactions, new antimicrobial compounds can be discovered and subsequently used to fight against such concerns. This study discusses the recent developments in antimicrobial medication discovery using isocyanide-based multicomponent reactions (IMCRs). Furthermore, the article emphasizes the potential of IMCRs (Isocyanide-based multicomponent based reactions) in the near future.

Exploring BODIPY derivatives as photosensitizers for antibacterial photodynamic therapy

There is urgently needed to develop efficient and safe antimicrobials to replace traditional antibiotics for fighting drug-resistant bacteria. Antimicrobial photodynamic therapy (aPDT), which is a promising antimicrobial strategy that can minimize antibiotic resistance and reduce systemic side effects. Boron-dipyrromethene (BODIPY) is a type of fascinating photosensitizers (PSs) for improving aPDT due to the tunable structures and photophysical features. Herein, six kinds of BODIPY derivatives (BDP1-BDP6) modified with different atoms or groups such as iodine atoms, thiophene, cyano, phenyl, aldehyde and nitro groups were synthesized and their photophysical behaviors were characterized. The results indicated that BDP3, which had 2, 6-diiodo and 8-phenyl substitution, was the best PS candidate with the highest reactive oxygen species (ROS) generation efficacy. BDP3 and BDP5 could rapidly kill Staphylococcus aureus (S. aureus) with the minimum inhibitory concentration (MIC) of 10 nM upon illumination. They also possessed excellent biofilm inhibition ability against S. aureus and could efficaciously restrain the formation of bacterial biofilm. The results of Live/Dead staining assay and scanning electron microscopy (SEM) demonstrated that BDP3 destroyed the cell membrane structure of bacteria by generating ROS, which ultimately led to bacterial lysis and death. Finally, the biosafety evaluation toward the mouse fibroblasts (L929 cells) suggested BDP3 had good cytocompatibility. This work exhibits the great potential of rational designs of PS for aPDT applications.

Nanoparticle Systems for Cancer Phototherapy: An Overview

Photodynamic therapy (PDT) and photothermal therapy (PTT) are photo-mediated treatments with different mechanisms of action that can be addressed for cancer treatment. Both phototherapies are highly successful and barely or non-invasive types of treatment that have gained attention in the past few years. The death of cancer cells because of the application of these therapies is caused by the formation of reactive oxygen species, that leads to oxidative stress for the case of photodynamic therapy and the generation of heat for the case of photothermal therapies. The advancement of nanotechnology allowed significant benefit to these therapies using nanoparticles, allowing both tuning of the process and an increase of effectiveness. The encapsulation of drugs, development of the most different organic and inorganic nanoparticles as well as the possibility of surfaces' functionalization are some strategies used to combine phototherapy and nanotechnology, with the aim of an effective treatment with minimal side effects. This article presents an overview on the use of nanostructures in association with phototherapy, in the view of cancer treatment.

Synthesis and Self-Assembly of Thermoresponsive Biohybrid Graft Copolymers Based on a Combination of Passerini Multicomponent Reaction and Molecular Recognition

Amphiphilic graft copolymers exhibit fascinating self-assembly behaviors. Their molecular architectures significantly affect the morphology and functionality of the self-assemblies. Considering the potential application of amphiphilic graft copolymers in the fabrication of nanocarriers, it is essential to synthesize well-defined graft copolymers with desired functional groups. Herein, the Passerini reaction and molecular recognition are introduced to the synthesis of functional thermoresponsive graft copolymers. A bifunctional monomer 2-((adamantan-1-yl)amino)-1-(4-((2-bromo-2-methylpropanoyl)oxy)phenyl)-2-oxoethyl methacrylate (ABMA) with a bromo group for atom transfer radical polymerization (ATRP) and an adamantyl group for molecular recognition is synthesized through the Passerini reaction. The graft copolymers are prepared by reversible addition-fragmentation transfer (RAFT) copolymerization of ABMA and oligo(ethylene glycol) methyl ether methacrylate (OEGMA) followed by RAFT end group removal and ATRP of di(ethylene glycol)methyl ether methacrylate (DEGMA) initiated by the ABMA units. The graft copolymer P(OEGMA-co-ABMA)-g-PDEGMA can be functionalized with β-cyclodextrin modified peptides, affording a thermoresponsive biohybrid graft copolymer. At a temperature above its lower critical solution temperature, the biohybrid graft copolymer self-assembles into peptide-modified polymersomes.

A pseudohomogeneous nanocarrier based on carbon quantum dots decorated with arginine as an efficient gene delivery vehicle

A pseudohomogeneous carrier as an emerging term refers to subnanometric carbon-based vehicle with a high ability to interact with genetic materials to form stable carboplex and successfully transfer them into the cell which will result in inhibiting or expressing of therapeutic genes. Chitosan is a non-toxic polyaminosaccharide used as a precursor in the presence of citric acid to produce carbon quantum dots (CQDs), which decorated with arginine as a surface passivation agent with high amine density in hydrothermal methodology. The Arginine-CQDs are comprehensively characterized by Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), Atomic force microscopy (AFM), field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray (EDX) mapping, fluorescence, High-resolution transmission electron microscopy (HR-TEM), zeta potential and X-ray powder diffraction (XRD). In this regard, for the first time, carboplex are formed by electrostatic conjugating of Arginine-CQDs with DNA to protect it from enzymatic degradation. Moreover, the carboplex, like the chitosan precursor, has not shown toxicity against AGS cell line. Interestingly, the Arginine-CQDs have exhibited an excellent ability to overcome cell barriers to deliver into cells compared to chitosan at the same weight ratio. The Arginine-CQDs/pEGFP (W/W) nanocomplex, not only lead to transfection with a relatively higher efficiency than PEI polymer, which is the "golden standard", but carboplex also demonstrates no significant toxicity. Indeed, the EGFP expression level has reached to 2.4 ± 0.2 via Arginine-CQDs carboplex at W/W 50 weight ratio. To the best of our knowledge, this is the first report includes chitosan-based CQDs functionalized by arginine which is applied to serve as a pseudohomogeneous vehicle for gene transfection.

Tailoring nanoparticles based on boron dipyrromethene for cancer imaging and therapy

Boron dipyrromethene (BODIPY), as a traditional fluorescent dye, has drawn increasing attention because of its excellent photophysical properties like adjustable spectra and outstanding photostability. BODIPY dyes could be assembled into nanoparticles for cancer imaging and therapy via rational design. In this review, the bio-applications of BODIPY-containing nanoparticles are introduced in detail, such as cellular imaging, near-infrared fluorescence imaging, computed tomography imaging, photoacoustic imaging, phototherapy, and theranostics. The construction strategies of BODIPY-containing nanoparticles are emphasized so the review has three sections-self-assembly of small molecules, chemical conjugation with hydrophilic compounds, and physical encapsulation. This review not only summarizes various and colorific bio-applications of BODIPY-containing nanoparticles, but also provides reasonable design methods of BODIPY-containing nanoparticles for cancer theranostics. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Engineering pH-Responsive BODIPY Nanoparticles for Tumor Selective Multimodal Imaging and Phototherapy

It is a challenge to develop multifunctional theranostic agents in one molecule, which simultaneously possesses tumor imaging ability with a high signal-to-noise ratio and excellent therapeutic activity. In this work, we synthesized and screened a series of BODIPY (BDP) with various absorption and fluorescence. The interplay of the molecular structure, pH-sensitive absorption and emission, and photodynamic and photothermal activities was well studied in detail. Photoinduced electron transfer, intramolecular charge transfer, and heavy atom effect were leveraged to engineer BDP with tumor imaging and therapeutic functions. The BDP nanoparticle formulations possessed multifunctional biological features, including selective treatment of cancer cells, near-infrared fluorescence, photoacoustic and computed tomography imaging, and photodynamic and photothermal therapy, as validated by cellular and animal experiments. These results not only give a new horizon to multifunctional BDP for biological applications but also show a new way to design the organic dye for tumor imaging and phototherapy.

Self-assembling poly(ethylene glycol)-block-polylactide-cabazitaxel conjugate nanoparticles for anticancer therapy with high efficacy and low in vivo toxicity

Traditional approaches used for transforming hydrophobic anticancer drugs into therapeutically available nanoparticles heavily rely on the noncovalent formulation of drugs within amphiphilic copolymers. However, these nanotherapies have not yet shown the expected favorable clinical outcomes in cancer patients, presumably due to their insufficient stability. To solve this dilemma, we conceive a new class of nanotherapies assembled with polymeric prodrugs that maintain pharmacological activity while substantially alleviate the drug toxicity in animals. By exploiting methoxypoly(ethylene glycol)-block-poly(D, L-lactic acid) (mPEG-PLA) as a promoiety, cabazitaxel is tethered to the terminus of the PLA fragment via a hydrolysable ester linkage. These conjugates recapitulate the self-assembly to produce colloidal stable nanotherapies. In a xenograft model of prostate cancer, this nanotherapy shows a durable inhibition of tumor progression upon the administration of a tolerable dose. Our results suggest that a hydrophobic and highly toxic drug can be rationally converted into a pharmacologically efficient and self-deliverable nanotherapy.

Optically Active Nanomaterials for Bioimaging and Targeted Therapy

Non-invasive tracking for monitoring the selective delivery and transplantation of biotargeted agents in vivo has been employed as one of the most effective tools in the field of nanomedicine. Different nanoprobes have been developed and applied to bioimaging tissues and the treatment of diseases ranging from inflammatory and cardiovascular diseases to cancer. Herein, we will review the recent advances in the development of optics-responsive nanomaterials, including organic and inorganic nanoparticles, for multimodal bioimaging and targeted therapy. The main focus is placed on nanoprobe fabrication, mechanistic illustrations, and diagnostic, or therapeutical applications. These nanomedicine strategies have promoted a better understanding of the biological events underlying diverse disease etiologies, thereby facilitating diagnosis, illness evaluation, therapeutic effect, and drug discovery.

Self-destructive PEG–BODIPY nanomaterials for photodynamic and photothermal therapy

Amphiphilic photosensitizers are made from boron dipyrromethene and poly(ethylene glycol) by using a thioketal linker, which is reactive oxygen species-responsive for photodynamic and photothermal therapy.

Reduction-sensitive polymeric nanomedicines: An emerging multifunctional platform for targeted cancer therapy

The development of smart delivery systems that are robust in circulation and quickly release drugs following selective internalization into target cancer cells is a key to precision cancer therapy. Interestingly, reduction-sensitive polymeric nanomedicines showing high plasma stability and triggered cytoplasmic drug release behavior have recently emerged as one of the most exciting platforms for targeted delivery of various anticancer drugs including small chemical drugs, proteins, and nucleic acids. In vivo studies in varying tumor models reveal that these reduction-sensitive multifunctional nanomedicines outperform the currently used clinical formulations and reduction-insensitive counterparts, bringing about not only significantly enhanced tumor selectivity, accumulation and inhibition efficacy but also markedly reduced systemic toxicity and improved therapeutic index. In this review, we will highlight the cutting-edge advancement with a focus on in vivo performances as well as future perspectives on reduction-sensitive polymeric nanomedicines for targeted cancer therapy.

The Effect of Molecular Structure on Cytotoxicity and Antitumor Activity of PEGylated Nanomedicines

Fundamental studies on the cellular uptake and drug release of PEGylated nanomedicines are beneficial to understand their fate in vivo and construct ideal nanoparticle formulations. In this work, the detailed metabolic process of PEGylated doxorubicin (Dox) nanomedicines were investigated via confocal laser scanning microscopy (CLSM), flow cytometry (FCM), cytotoxicity test, fluorescence imaging in vivo (FLIV) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Among them, only LC-MS/MS could accurately determine the content of PEGylated Dox and Dox in vitro and in vivo. To the best of our knowledge, this was the first time the PEGylated Dox and released Dox were simultaneously quantified. The interplay of molecular structures, cellular uptake, drug release, and antitumor effect was well characterized. PEG with high molecular weight impeded the cellular uptake of nanoparticles, and the acid-labile hydrazone bond between Dox and PEG promoted Dox release significantly. Cellular uptake and drug release play decisive roles in cytotoxicity and antitumor effect, as evidenced by LC-MS/MS. We emphasized that LC-MS/MS would be a practicable method to quantify PEGylated drugs without complex tags, which could be more in-depth to understand the interaction between PEGylated nanomedicines and their antitumor efficacy.

Constructing reduction-sensitive PEGylated NIRF mesoporous silica nanoparticles via a one-pot Passerini reaction for photothermal/chemo-therapy

For the first time, we have obtained a multifunctional nanoplatform (MSN-BDP-PEG) containing disulfide bonds, BODIPY 5 and PEG-CHO via a one-pot Passerini reaction for chemotherapy, phototherapy and NIRF imaging.