Methods for CRISPR-Cas as Ribonucleoprotein Complex Delivery In Vivo

The efficient delivery of CRISPR-Cas components is still a key and unsolved problem. CRISPR-Cas delivery in the form of a Cas protein+sgRNA (ribonucleoprotein complex, RNP complex), has proven to be extremely effective, since it allows to increase on-target activity, while reducing nonspecific activity. The key point for in vivo genome editing is the direct delivery of artificial nucleases and donor DNA molecules into the somatic cells of an adult organism. At the same time, control of the dose of artificial nucleases is impossible, which affects the efficiency of genome editing in the affected cells. Poor delivery efficiency and low editing efficacy reduce the overall potency of the in vivo genome editing process. Here we review how this problem is currently being solved in scientific works and what types of in vivo delivery methods of Cas9/sgRNA RNPs have been developed.

Dendrimer-based drug delivery systems: history, challenges, and latest developments

Since the first dendrimer was reported in 1978 by Fritz Vögtle, dendrimer research has grown exponentially, from synthesis to application in the past four decades. The distinct structure characteristics of dendrimers include nanoscopic size, multi-functionalized surface, high branching, cavernous interior, and so on, making dendrimers themselves ideal drug delivery vehicles. This mini review article provides a brief overview of dendrimer’s history and properties and the latest developments of dendrimers as drug delivery systems. This review focuses on the latest progress in the applications of dendrimers as drug and gene carriers, including 1) active drug release strategies to dissociate drug/gene from dendrimer in response to stimuli; 2) size-adaptive and charge reversal dendrimer delivery systems that can better take advantage of the size and surface properties of dendrimer; 3) bulk and micro/nano dendrimer gel delivery systems. The recent advances in dendrimer formulations may lead to the generation of new drug and gene products and enable the development of novel combination therapies.

pH-Regulated Single and Double Charge Inversions on PEI-Coated Surfaces

The pH-regulated charge inversions on polyethylenimine (PEI)-coated surfaces are indispensable to their applications in biomaterials and nanomaterials. Various PEI-coated surfaces, where single charge inversion happens, have been extensively investigated, while the surfaces where double charge inversion appears are less reported. Here, using a molecular theory, we systematically study the pH-regulated charge density of PEI-coated surfaces. The results suggest whether single or double charge inversion happens depends on PEI affinity to the surface and the bare surface charge density. The region of double charge inversion is much smaller than that of single charge inversion, revealing the reason why double charge inversion is less observed in experiments. Besides, the charge inversions are significantly influenced by the solution condition. The present work provides a useful guideline to the selection of the coated materials and the parameters of PEI solution in the design of PEI-coated surfaces aiming to promote their applications in multifunctional nanomaterials.

Construction of Intelligent Responsive Drug Delivery System and Multi-Mode Imaging Based on Gold Nanodots

Cancer remains a formidable global problem with a high mortality rate. There are many effective anti-cancer drugs in clinical use, among which paclitaxel (PTX) has good effects on non-small cell lung cancer, ovarian cancer and breast cancer. However, when applied to the clinic, PTX still has many limitations, such as poor water solubility, drug resistance and large side effects on healthy tissues. We constructed an Au nanodots-paclitaxel-polylysine (AuNDs-PTX-PLL) core-shell nano-system of integrated diagnosis and treatment to achieve intelligent responsive drug delivery. On the one hand, the problem of poor water-solubility and the drug resistance of PTX are solved. On the other hand, the nano-system has an excellent intelligent response effect. Drugs can only be released in the weakly acidic environment of the tumor, which reduces the damage and side effects to normal tissues. Moreover, the nano-system can be used for real-time tracking and auxiliary diagnosis for the tumor through the multi-mode imaging mode, such as fluorescence, photoacoustic and computed tomography to achieve accurate visualization. The photothermal effect of AuNDs is beneficial to promote the release of drugs. The nano-system integrates multi-mode imaging, chemotherapy, intelligent drug release in tumor weakly acidic environment, and has excellent practical application prospect in tumor diagnosis and treatment. This article is protected by copyright. All rights reserved.

Degradable Bactericide Constructed Using a Charge-Reversal Surfactant against Plant Pathogenic Bacteria

Plant bacterial diseases are serious problems in agriculture, posing threats to global food security and the agricultural economy. Here, a degradable agricultural bactericide AMC-10 constructed using a charge-reversal surfactant, from being positively charged to negatively charged, was designed and synthesized. AMC-10 possessed high bactericidal activity toward plant pathogenic bacteria, consequently being able to inhibit the corresponding plant bacterial diseases. After degradation by water, the hydrolyzed products were nontoxic to bacteria and human cells. Such a degradable bactericide provides new ideas for the design of environmentally friendly agricultural bactericides. It is anticipated that degradable bactericides such as AMC-10 can be applied in the prevention and control of plant bacterial diseases, being less likely to produce toxicity or drug resistance.

Surface-modified polymeric nanoparticles for drug delivery to cancer cells

INTRODUCTION

The utilization of polymeric nanoparticles, as drug payloads, has been extensively prevailed in cancer therapy. However, the precise distribution of these nanocarriers is restrained by various physiological and cellular obstacles. Nanoparticles must avoid nonspecific interactions with healthy cells and in vivo compartments to circumvent these barriers. Since in vivo interactions of nanoparticles are mainly dependent on surface properties of nanoparticles, efficient control on surface constituents is necessary for the determination of nanoparticles' fate in the body.

AREAS COVERED

In this review, the surface-modified polymeric nanoparticles and their utilization in cancer treatment were elaborated. First, the interaction of nanoparticles with numerous in vivo barriers was highlighted. Second, different strategies to overcome these obstacles were described. Third, some inspiring examples of surface-modified nanoparticles were presented. Later, fabrication and characterization methods of surface-modified nanoparticles were discussed. Finally, the applications of these nanoparticles in different routes of treatments were explored.

EXPERT OPINION

Surface modification of anticancer drug-loaded polymeric nanoparticles can enhance the efficacy, selective targeting, and biodistribution of the anticancer drug at the tumor site.

Fabrication of egg shell-like nanovesicles from a thiocoumarin-based ε-amino ester: a potential carrier

A thiocoumarin-based ε-amino ester has been designed and synthesized and used to fabricate egg shell-like nanovesicles for sustained release of sulfamethoxazole antibiotic.

Facile Assembly of Large-Area 2D Microgel Colloidal Crystals Using Charge-Reversible Substrates

2D colloidal crystals (CCs) have important applications; however, the fabrication of large-area, high-quality 2D CCs is still far from being trivial, and the fabrication of 2D microgel CCs is even harder. Here, we have demonstrated that they can be facilely fabricated using charge-reversible substrates. The charge-reversible substrates were prepared by modification with amino groups. The amino groups were then protected by amidation with 2,2-dimethylsuccinic anhydride. At acidic pH, the surface charge of the modified substrate will change from negative to positive as a result of the hydrolysis of the amide bonds and the regeneration of the amino groups. 2D microgel CCs can be simply fabricated by applying a concentrated microgel dispersion on the modified substrate. The negatively charged surface of the substrate allows the negatively charged microgel spheres, especially those close to the substrate, to self-assemble into 3D CCs. With the gradual hydrolysis of the amide bonds and the charge reversal of the substrate, the first 111 plane of the 3D assembly is fixed in situ on the substrate. The resulting 2D CC has a high degree of ordering because of the high quality of the parent 3D microgel CC. Because large-area 3D microgel CCs can be facilely fabricated, this method allows for the fabrication of 2D CCs of any size. Nonplanar substrates can also be used. In addition, the interparticle distance of the 2D array can be tuned by the concentration of the microgel dispersion. Besides rigid substrates (such as glass slides, quartz slides, and silicon wafers), flexible polymer films, including polyethylene terephthalate and poly(vinyl chloride) films, were also successfully used as substrates for the fabrication of 2D microgel CCs.

Hydrogen Sulfide Triggered Charge-Reversal Micelles for Cancer-Targeted Drug Delivery and Imaging

Currently, the development of polymeric micelles combining diagnosis and targeted therapy is theoretically and practically significant in cancer treatment. In addition, it has been reported that cancer cells can produce large amounts of hydrogen sulfide (H2S) and their survival depends on the content of H2S. In this study, a series of N-(2-hydroxyethyl)-4-azide-1,8-naphthalimide ended amphiphilic diblock copolymer poly(2-hydroxyethyl methacrylate)-block-poly(methyl methacrylate) (N3-Nap-PHEMA-b-PMMA-N3) micelles were prepared. Around cancer tissues, the N3-Nap-PHEMA45-b-PMMA42-N3 micelles exhibited dual characteristics of monitoring H2S and H2S triggered charge reversal with the reduction of the azido group. The surface charge of N3-Nap-PHEMA45-b-PMMA42-N3 micelles reversed from negative to positive after monitoring H2S. With H2S triggered charge reversal, the cellular uptake of DOX-loaded N3-Nap-PHEMA45-b-PMMA42-N3 micelles was effectively enhanced through electrostatic attraction mediated targeting, and a fast doxorubicin (DOX) release rate was observed. The MTT assay demonstrated that N3-Nap-PHEMA45-b-PMMA42-N3 micelles were biocompatible to HeLa cells, and DOX-loaded N3-Nap-PHEMA45-b-PMMA42-N3 micelles showed enhanced cytotoxicity in HeLa cells in the presence of H2S. Furthermore, in vivo fluorescence imaging and biodistribution experiments revealed that DOX-loaded N3-Nap-PHEMA45-b-PMMA42-N3 micelles could provide good tumor imaging and accumulate in tumor tissue. Therefore, N3-Nap-PHEMA45-b-PMMA42-N3 micelles can be used as a promising platform for tumor diagnosis and therapy.

Tailor-Made Temperature-Sensitive Micelle for Targeted and On-Demand Release of Anticancer Drugs

The design of nanomedicines from the tuned architecture polymer is a leading object of immense research in recent years. Here, smart thermoresponsive micelles were prepared from novel architecture four-arm star block copolymers, namely, pentaerythritol polycaprolactone-b-poly(N-isopropylacrylamide) and pentaerythritol polycaprolactone-b-poly(N-vinylcaprolactam). The polymers were synthesized and tagged with folic acid (FA) to render them as efficient cancer cell targeting cargos. FA-conjugated block copolymers were self-assembled to a nearly spherical (ranging from 15 to 170 nm) polymeric micelle (FA-PM) with a sufficiently lower range of critical micelle concentration (0.59 × 10(-2) to 1.52 × 10(-2) mg/mL) suitable for performing as an efficient drug carrier. The blocks show lower critical solution temperature (LCST) ranging from 30 to 39 °C with high DOX-loading content (24.3%, w/w) as compared to that reported for a linear polymer in the contemporary literature. The temperature-induced reduction in size (57%) of the FA-PM enables a high rate of DOX release (78.57% after 24 h) at a temperature above LCST. The DOX release rate has also been tuned by on-demand administration of temperature. The in vitro biocompatibilities of the blank and DOX-loaded FA-PMs have been studied by the MTT assay. The cellular uptake study proves selective internalization of the FA-PM into cancerous cells (C6 glioma) compared that into normal cells (HaCaT). In vivo administration of the DOX-loaded FA-PMs into the C6 glioma rat tumor model resulted in significant accumulation in tumor sites, which drastically inhibited the tumor volume by ∼83.9% with respect to control without any significant systemic toxicity.

Fluorene–morpholine-based organic nanoparticles: lysosome-targeted pH-triggered two-photon photodynamic therapy with fluorescence switch on–off

We synthesized fluorene–morpholine NPs that showed reversible fluorescence switch ON–OFF properties, which rendered the real time monitoring of PDT activity.

Self-assembled peptide microspheres for sustainable release of sulfamethoxazole

Porous peptide microspheres have been used for the loading and sustained release of the bacteriostatic antibiotic sulfamethoxazole.

pHe-induced charge-reversible NIR fluorescence nanoprobe for tumor-specific imaging

Inspired by the specificity of acid tumor microenvironment, we constructed a flexible charge-reversible near-infrared (NIR) fluorescence nanoprobe in response to tumor extracellular pH (pHe) for effective tumor-specific imaging. The nanoprobe consists of an NIR-emitted CuInS2/ZnS quantum dot (CIS/ZS QDs) core and a tailored lauric acid and 2,3-dimethylmaleic anhydride modified ε-polylysine (ε-PL-g-LA/DMA) shell, which provides not only a dense protective layer for the QDs but also the ability of pHe-induced positive charge-mediated endocytosis into tumor cells. The results showed that the QDs@ε-PL-g-LA/DMA nanoprobe with a uniform size of 40 nm had high chemical stability at pH 7.4 and excellent optical properties. Especially, it swiftly reversed its surface charge to positive in 20 min when exposed to pHe due to the cleavage of the β-carboxyl amide bond of ε-PL-g-LA/DMA. Moreover, the cell uptake of the pHe-sensitive QDs nanoprobe exposed at pH 6.8 into HeLa cells is much more significant than that at pH 7.4, which further verified the availability of the electrostatic adsorptive endocytosis facilitated targeting ability. The pHe-induced targeting imparted the QDs nanoprobe a broad targeting ability in a variety of solid tumors. Furthermore, as an effective alternative mechanism for tumor targeting, responsive charge reversion is also universally applicable to other cancer theranostics agent.

Mechanisms and implications of dual-acting methotrexate in folate-targeted nanotherapeutic delivery

The rational design of a nanoplatform in drug delivery plays a crucial role in determining its targeting specificity and efficacy in vivo. A conventional approach relies on the surface conjugation of a nanometer-sized particle with two functionally distinct types of molecules, one as a targeting ligand, and the other as a therapeutic agent to be delivered to the diseased cell. However, an alternative simplified approach can be used, in which a single type of molecule displaying dual function as both a targeting ligand and therapeutic agent is conjugated to the nanoparticle. In this review, we evaluate the validity of this new strategy by using methotrexate, which displays multifunctional mechanisms of action. Methotrexate binds to the folate receptor, a surface biomarker frequently overexpressed in tumor cells, and also inhibits dihydrofolate reductase, an enzyme critical for cell survival and division. Thus we describe a series of fifth generation poly(amido amine) dendrimers conjugated with methotrexate, and discuss several lines of evidence supporting the efficacy of this new platform strategy based on surface plasmon resonance spectroscopy, enzyme activity assays, and cell-based studies with folate receptor (+) KB cancer cells.

A multifunctional PEG–PLL drug conjugate forming redox-responsive nanoparticles for intracellular drug delivery

Tumor-targeting camptothecin (CPT)-conjugated nanoparticles with high stability and GSH-triggered drug release were developed for cancer targeting drug delivery.

Virus-inspired mimics: self-assembly of dendritic lipopeptides into arginine-rich nanovectors for improving gene delivery

With inspirations from natural viruses, arginine-containing dendritic lipopeptides were designed for bioinspired fabrication.

Thermo and pH dual-controlled charge reversal amphiphilic graft copolymer micelles for overcoming drug resistance in cancer cells

A novel thermo and pH dual-controlled charge reversal PSMA₈₉-g-P(DMA₁₆-co-SD₅₆) graft copolymer micelle was developed with effectively enhanced cellular uptake for overcoming multi-drug resistance in cancer cells.

Multicomponent polymeric nanoparticles enhancing intracellular drug release in cancer cells

Three kinds of amphiphilic copolymer, that is, poly(ε-caprolactone)-SS-poly(ethylene glycol) (PCL-SS-PEG), poly(ε-caprolactone)-polyethylenimine (PCL-PEI), and poly(ε-caprolactone)-polyethylenimine-folate (PCL-PEI-Fol) were synthesized and self-assembled into surface engineered hybrid nanoparticles (NPs). Morphological studies elucidated the stable, spherical, and uniform sandwich structure of the NPs. PCL-PEI and PCL-SS-PEG segments have introduced pH and reduction responsive characteristics in these NPs, while PCL-PEI-FA copolymers could provide specific targeting capability to cancer cells. The stimuli responsive capabilities of these NPs were carried out. Negative-to-positive charge reversible property, in response to the pH change, was investigated by zeta potential and nuclear magnetic resonance (NMR) measurements. The structure cleavage, due to redox gradient, was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). These NPs showed controlled degradation, better drug release, less toxicity, and effective uptake in MCF-7 breast cancer cells. These multifunctional NPs showed promising potential in the treatment of cancer.

Nanostructural systems developed with positive charge generation to drug delivery

The surface charge of a nanostructure plays a critical role in modulating blood circulation time, nanostructure-cell interaction, and intracellular events. It is unfavorable to have positive charges on the nanostructure surface before arriving at the disease site because positively charged nanostructures interact strongly with blood components, resulting in rapid clearance from the blood, and suboptimal targeted accumulation at the tumor site. Once at the tumor site, however, the positive charge on the nanostructure surface accelerates uptake by tumor cells and promotes the release of payloads from the lysosomes to the cytosol or nucleus inside cells. Thus, the ideal nanocarrier systems for drug delivery would maintain a neutral or negatively charged surface during blood circulation but would then generate a positive surface charge after accumulation at the tumor site or inside the cancer cells. This Progress Report focuses on the design and application of various neutral or negatively charged nanostructures that can generate a positive charge in response to the tumor microenvironment or an external stimulus.

Tailor-made charge-conversional nanocomposite for pH-responsive drug delivery and cell imaging

Imaging labels, therapeutic drugs, as well as many other agents can all be integrated into one nanoplatform to allow for molecular imaging and therapy. With this in mind, herein we report the first example of a tailor-made charge-conversional nanocomposite composed of mesoporous γ-AlO(OH) and upconversion nanoparticles (UCNPs) via a simple and versatile method, and the obtained nanocomposite could be performed as a drug delivery carrier and applied for cell imaging. The nanocomposite (UCNPs-Al) was found to be able to efficiently transport DOX, a typical chemotherapeutic anticancer drug, into the cancer cell and release DOX from UCNPs-Al triggering by the mildly acidic environment. In vitro cell cytotoxicity assay verified that DOX-loaded nanocomposites (UCNPs-Al-DOX) exhibited greater cytotoxicity with respect to free DOX at the same concentrations, because of the increase in cell uptake of anti-cancer drug delivery vehicles mediated by the charge-conversional property. Moreover, the UCL emission from UCNPs and the red fluorescence of DOX allow the nanocomposite to track and monitor the drug delivery system simultaneously. These findings have opened up new insights into designing and producing the highly versatile multifunctional nanoparticles for simultaneous imaging and therapeutic applications.

Synthesis and in vitro evaluation of charge reversal photoresponsive quinoline tethered mesoporous silica for targeted drug delivery

We developed excellent charge reversal photoresponsive nanoparticles for targeted delivery of the anticancer drug chlorambucil.

Shining light on nuclear-targeted therapy using gold nanostar constructs

Nuclear-targeted therapy has received increasing attention as a potential strategy to improve the therapeutic efficacy of treating cancer. The main challenges include targeting, drug-delivery efficiency and release of anticancer agents to the cancer cell nucleus. Nanoparticles as nanocarriers have started to address some of these issues. However, a lack of understanding in how nanoconstructs interact with the nucleus has precluded detailed studies. In this article, we highlight a nanoconstruct composed of gold (Au) nanostars loaded with nucleolin-specific aptamers. This nanoconstruct induced major changes in the nuclear phenotype through nuclear envelope (NE) invaginations. Femtosecond, light-triggered release of the aptamers from the surface of the Au nanostars further increased the number of NE deformations. Cancer cells with more NE folding showed increased apoptosis as well as decreased cell viability. The author's of this article have revealed that correlation between drug-induced changes in nuclear phenotypes and increased therapeutic efficacy can provide new insight into nuclear-targeted cancer therapy.

Stimulus-sensitive polymeric nanoparticles and their applications as drug and gene carriers

Polymeric nanoparticles are promising candidates as drug and gene carriers. Among polymeric nanoparticles, those that are responsive to internal or external stimuli are of greater interest because they allow more efficient delivery of therapeutics to pathological regions. Stimulus-sensitive polymeric nanoparticles have been fabricated based on numerous nanostructures, including micelles, vesicles, crosslinked nanoparticles, and hybrid nanoparticles. The changes in chemical or physical properties of polymeric nanoparticles that occur in response to single, dual, or multiple stimuli endow these nanoparticles with the ability to retain cargoes during circulation, target the pathological region, and release their cargoes after cell internalization. This Review focuses on the most recent developments in the preparation of stimulus-sensitive polymeric nanoparticles and their applications in drug and gene delivery.

Cationic polymers and their therapeutic potential

The last decade has witnessed enormous research focused on cationic polymers. Cationic polymers are the subject of intense research as non-viral gene delivery systems, due to their flexible properties, facile synthesis, robustness and proven gene delivery efficiency. Here, we review the most recent scientific advances in cationic polymers and their derivatives not only for gene delivery purposes but also for various alternative therapeutic applications. An overview of the synthesis and preparation of cationic polymers is provided along with their inherent bioactive and intrinsic therapeutic potential. In addition, cationic polymer based biomedical materials are covered. Major progress in the fields of drug and gene delivery as well as tissue engineering applications is summarized in the present review.