Efficient Subcellular Targeting to the Cell Nucleus of Quantum Dots Densely Decorated with a Nuclear Localization Sequence Peptide

Polypeptides-Based Nanocarriers in Tumor Therapy

Cancer remains a worldwide problem, and new treatment strategies are being actively developed. Peptides have the characteristics of good biocompatibility, strong targeting, functional diversity, modifiability, membrane permeable ability, and low immunogenicity, and they have been widely used to construct targeted drug delivery systems (DDSs). In addition, peptides, as endogenous substances, have a high affinity, which can not only regulate immune cells but also work synergistically with drugs to kill tumor cells, demonstrating significant potential for application. In this review, the latest progress of polypeptides-based nanocarriers in tumor therapy has been outlined, focusing on their applications in killing tumor cells and regulating immune cells. Additionally, peptides as carriers were found to primarily provide a transport function, which was also a subject of interest to us. At the end of the paper, the shortcomings in the construction of peptide nano-delivery system have been summarized, and possible solutions are proposed therein. The application of peptides provides a promising outlook for cancer treatment, and we hope this article can provide in-depth insights into possible future avenues of exploration.

Nanoassemblies designed for efficient nuclear targeting

One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.

An easy and simple method for the immobilization of dyes through click reactions: activated alkyne, copper not needed

The copper-free azide-alkyne click reaction has shown to be a successful alternative to immobilize covalently a fluorescente compound onto poly(-l-lactic) acid (PLLA) surfaces. Proceded by basic hydrolysis and amidation reaction, typical surface characterization techniques have validated each functionaliztion step and the success of the conjugation. This method offers a catalyst-free option for various surface conjugations, extremely demanded in biomedical and biosensory fields.

Adapting the in vitro micronucleus assay (OECD Test Guideline No. 487) for testing of manufactured nanomaterials: recommendations for best practices

The current Organisation for Economic Co-Operation and Development test guideline number 487 (OECD TG No. 487) provides instruction on how to conduct the in vitro micronucleus assay. This assay is one of the gold standard approaches for measuring the mutagenicity of test items; however, it is directed at testing low molecular weight molecules and may not be appropriate for particulate materials (e.g. engineered nanoparticles [ENPs]). This study aimed to adapt the in vitro micronucleus assay for ENP testing and underpins the development of an OECD guidance document. A harmonized, nano-specific protocol was generated and evaluated by two independent laboratories. Cell lines utilized were human lymphoblastoid (TK6) cells, human liver hepatocytes (HepG2) cells, Chinese hamster lung fibroblast (V79) cells, whole blood, and buffy coat cells from healthy human volunteers. These cells were exposed to reference ENPs from the Joint Research Council (JRC): SiO2 (RLS-0102), Au5nm and Au30nm (RLS-03, RLS-010), CeO2 (NM212), and BaSO4 (NM220). Tungsten carbide-cobalt (WC/Co) was used as a trial particulate positive control. The chemical controls were positive in all cell cultures, but WC/Co was only positive in TK6 and buffy coat cells. In TK6 cells, mutagenicity was observed for SiO2- and both Au types. In HepG2 cells, Au5nm and SiO2 showed sub-two-fold increases in micronuclei. In V79 cells, whole blood, and buffy coat cells, no genotoxicity was detected with the test materials. The data confirmed that ENPs could be tested with the harmonized protocol, additionally, concordant data were observed across the two laboratories with V79 cells. WC/Co may be a suitable particulate positive control in the in vitro micronucleus assay when using TK6 and buffy coat cells. Detailed recommendations are therefore provided to adapt OECD TG No. 487 for testing ENP.

CRISPR/Cas gene editing and delivery systems for cancer therapy

CRISPR/Cas systems stand out because of simplicity, efficiency, and other superiorities, thus becoming attractive and brilliant gene-editing tools in biomedical field including cancer therapy. CRISPR/Cas systems bring promises for cancer therapy through manipulating and engineering on tumor cells or immune cells. However, there have been concerns about how to overcome the numerous physiological barriers and deliver CRISPR components to target cells efficiently and accurately. In this review, we introduced the mechanisms of CRISPR/Cas systems, summarized the current delivery strategies of CRISPR/Cas systems by physical methods, viral vectors, and nonviral vectors, and presented the current application of CRISPR/Cas systems in cancer clinical treatment. Furthermore, we discussed prospects related to delivery approaches of CRISPR/Cas systems. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

An update on the biological effects of quantum dots: From environmental fate to risk assessment based on multiple biological models

Quantum dots (QDs) are zero-dimension nanomaterials with excellent physical and chemical properties, which have been widely used in environmental science and biomedicine. Therefore, QDs are potential to cause toxicity to the environment and enter organisms through migration and bioenrichment effects. This review aims to provide a comprehensive and systematic analysis on the adverse effects of QDs in different organisms based on recently available data. Following PRISMA guidelines, this study searched PubMed database according to the pre-set keywords, and included 206 studies according to the inclusion and elimination criteria. CiteSpace software was firstly used to analyze the keywords of included literatures, search for breaking points of former studies, and summarize the classification, characterization and dosage of QDs. The environment fate of QDs in the ecosystems were then analyzed, followed with comprehensively summarized toxicity outcomes at individual, system, cell, subcellular and molecular levels. After migration and degradation in the environment, aquatic plants, bacteria, fungi as well as invertebrates and vertebrates have been found to be suffered from toxic effects caused by QDs. Aside from systemic effects, toxicity of intrinsic QDs targeting to specific organs, including respiratory system, cardiovascular system, hepatorenal system, nervous system and immune system were confirmed in multiple animal models. Moreover, QDs could be taken up by cells and disturb the organelles, which resulted in cellular inflammation and cell death, including autophagy, apoptosis, necrosis, pyroptosis and ferroptosis. Recently, several innovative technologies, like organoids have been applied in the risk assessment of QDs to promote the surgical interventions of preventing QDs' toxicity. This review not only aimed at updating the research progress on the biological effects of QDs from environmental fate to risk assessment, but also overcame the limitations of available reviews on basic toxicity of nanomaterials by interdisciplinarity and provided new insights for better applications of QDs.

Efficient Synergistic Antibacterial Activity of α-MSH Using Chitosan-Based Versatile Nanoconjugates

The application of antimicrobial peptides has emerged as an alternative therapeutic tool to encounter against multidrug resistance of different pathogenic organisms. α-Melanocyte stimulating hormone (α-MSH), an endogenous neuropeptide, is found to be efficient in eradicating infection of various kinds of Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA). However, the chemical stability and efficient delivery of these biopharmaceuticals (i.e., α-MSH) to bacterial cells with a significant antibacterial effect remains a key challenge. To address this issue, we have developed a chitosan-cholesterol polymer using a single-step, one-pot, and simple chemical conjugation technique, where α-MSH is loaded with a significantly high amount (37.7%), and the final product is obtained as chitosan-cholesterol α-MSH polymer-drug nanoconjugates. A staphylococcal growth inhibition experiment was performed using chitosan-cholesterol α-MSH and individual controls. α-MSH and chitosan-cholesterol both show bacterial growth inhibition by a magnitude of 50 and 79%, respectively. The killing efficiency of polymer-drug nanoconjugates was very drastic, and almost no bacterial colony was observed (∼100% inhibition) after overnight incubation. Phenotypic alternation was observed in the presence of α-MSH causing changes in the cell structure and shape, indicating stress on Staphylococcus aureus. As a further consequence, vigorous cell lysis with concomitant release of the cellular material in the nearby medium was observed after treatment of chitosan-cholesterol α-MSH nanoconjugates. This vigorous lysis of the cell structure is associated with extensive aggregation of the bacterial cells evident in scanning electron microscopy (SEM). The dose-response experiment was performed with various concentrations of chitosan-cholesterol α-MSH nanoconjugates to decipher the degree of the bactericidal effect. The concentration of α-MSH as low as 1 pM also shows significant inhibition of bacterial growth (∼40% growth inhibition) of Staphylococcus aureus. Despite playing an important role in inhibiting bacterial growth, our investigation on hemolytic assay shows that chitosan-cholesterol α-MSH is significantly nontoxic at a wide range of concentrations. In a nutshell, our analysis demonstrated novel antimicrobial activity of nanoparticle-conjugated α-MSH, which could be used as future therapeutics against multidrug-resistant Staphylococcus aureus and other types of bacterial cells.

Quantum Dots and Their Interaction with Biological Systems

Quantum dots are nanocrystals with bright and tunable fluorescence. Due to their unique property, quantum dots are sought after for their potential in several applications in biomedical sciences as well as industrial use. However, concerns regarding QDs’ toxicity toward the environment and other biological systems have been rising rapidly in the past decade. In this mini-review, we summarize the most up-to-date details regarding quantum dots’ impacts, as well as QDs’ interaction with mammalian organisms, fungal organisms, and plants at the cellular, tissue, and organismal level. We also provide details about QDs’ cellular uptake and trafficking, and QDs’ general interactions with biological structures. In this mini-review, we aim to provide a better understanding of our current standing in the research of quantum dots, point out some knowledge gaps in the field, and provide hints for potential future research.

Bio-Conjugated Quantum Dots for Cancer Research: Detection and Imaging

Ultrasound, computed tomography, magnetic resonance, and gamma scintigraphy-based detection and bio-imaging technologies have achieved outstanding breakthroughs in recent years. However, these technologies still encounter several limitations such as insufficient sensitivity, specificity and security that limit their applications in cancer detection and bio-imaging. The semiconductor quantum dots (QDs) are a kind of newly developed fluorescent nanoparticles that have superior fluorescence intensity, strong resistance to photo-bleaching, size-tunable light emission and could produce multiple fluorescent colors under single-source excitation. Furthermore, QDs have optimal surface to link with multiple targets such as antibodies, peptides, and several other small molecules. Thus, QDs might serve as potential, more sensitive and specific methods of detection than conventional methods applied in cancer molecular targeting and bio-imaging. However, many challenges such as cytotoxicity and nonspecific uptake still exist limiting their wider applications. In the present review, we aim to summarize the current applications and challenges of QDs in cancer research mainly focusing on tumor detection, bio-imaging, and provides opinions on how to address these challenges.

Click and Bioorthogonal Chemistry: The Future of Active Targeting of Nanoparticles for Nanomedicines?

Over the years, click and bioorthogonal reactions have been the subject of considerable research efforts. These high-performance chemical reactions have been developed to meet requirements not often provided by the chemical reactions commonly used today in the biological environment, such as selectivity, rapid reaction rate, and biocompatibility. Click and bioorthogonal reactions have been attracting increasing attention in the biomedical field for the engineering of nanomedicines. In this review, we study a compilation of articles from 2014 to the present, using the terms "click chemistry and nanoparticles (NPs)" to highlight the application of this type of chemistry for applications involving NPs intended for biomedical applications. This study identifies the main strategies offered by click and bioorthogonal chemistry, with respect to passive and active targeting, for NP functionalization with specific and multiple properties for imaging and cancer therapy. In the final part, a novel and promising approach for "two step" targeting of NPs, called pretargeting (PT), is also discussed; the principle of this strategy as well as all the studies listed from 2014 to the present are presented in more detail.

Preparation and Characterization of Quantum Dot-Peptide Conjugates Based on Polyhistidine Tags

Quantum dots (QDs) offer bright and robust photoluminescence among several other advantages in comparison to fluorescent dyes. In order to leverage the advantageous properties of QDs for applications in bioanalysis and imaging, simple and reliable methods for bioconjugation are required. One such method for conjugating peptides to QDs is the use of polyhistidine tags, which spontaneously bind to the surface of QDs. We describe protocols for assembling polyhistidine-tagged peptides to QDs and for characterizing the resultant QD-peptide conjugates. The latter include both electrophoretic and FRET-based protocols for confirming successful peptide assembly, estimating the maximum peptide loading capacity, and measuring the assembly kinetics. Sensors for protease activity and intracellular delivery are briefly noted as prospective applications of QD-peptide conjugates.

Chemically Designed Nanoscale Materials for Controlling Cellular Processes

Nanoparticles are widely used in various biomedical applications as drug delivery carriers, imaging probes, single-molecule tracking/detection probes, artificial chaperones for inhibiting protein aggregation, and photodynamic therapy materials. One key parameter of these applications is the ability of the nanoparticles to enter into the cell cytoplasm, target different subcellular compartments, and control intracellular processes. This is particularly the case because nanoparticles are designed to interact with subcellular components for the required biomedical performance. However, cells are protected from their surroundings by the cell membrane, which exerts strict control over entry of foreign materials. Thus, nanoparticles need to be designed appropriately so that they can readily cross the cell membrane, target subcellular compartments, and control intracellular processes.In the past few decades there have been great advancements in understanding the principles of cellular uptake of foreign materials. In particular, it has been shown that internalization of foreign materials (small molecules, macromolecules, nanoparticles) is size-dependent: endocytotic uptake of materials requires sizes greater than 10 nm, and materials with sizes of 10-100 nm usually enter into cells by energy-dependent endocytosis via biomembrane-coated vesicles. Direct access to the cytosol is limited to very specific conditions, and endosomal escape of material appears to be the most practical approach for intracellular processing.In this Account, we describe how cellular uptake and intracellular processing of nanoscale materials can be controlled by appropriate design of size and surface chemistry. We first describe the cell membrane structure and principles of cellular uptake of foreign materials followed by their subcellular trafficking. Next, we discuss the designed surface chemistry of a 5-50 nm particle that offers preferential lipid-raft/caveolae-mediated endocytosis over clathrin-mediated endocytosis with minimum endosomal/lysosomal trafficking or energy-independent direct cell membrane translocation (without endocytosis) followed by cytosolic delivery without endosomal/lysosomal trafficking. In particular, we emphasize that the zwitterionic-lipophilic surface property of a nanoparticle offers preferential interaction with the lipid raft region of the cell membrane followed by lipid raft uptake, whereas a lower number of affinity biomolecules (<25) on the nanoparticle surface offers caveolae/lipid-raft uptake, while an arginine/guanidinium-terminated surface along with a size of <10 nm offers direct cell membrane translocation. Finally, we discuss how nanoprobes can be designed by adapting these surface chemistry and size preference principles so that they can readily enter into the cell, label different subcellular compartments, and control intracellular processes such as trafficking kinetics, exocytosis, autophagy, amyloid aggregation, and clearance of toxic amyloid aggregates. The Account ends with a Conclusions and Outlook where we discuss a vision for the development of subcellular targeting nanodrugs and imaging nanoprobes by adapting to these surface chemistry principles.

Methods for Intracellular Delivery of Quantum Dots

Quantum dots (QDs) have attracted considerable attention as fluorescent probes for life sciences. The advantages of using QDs in fluorescence-based studies include high brilliance, a narrow emission band allowing multicolor labeling, a chemically active surface for conjugation, and especially, high photostability. Despite these advantageous features, the size of the QDs prevents their free transport across the plasma membrane, limiting their use for specific labeling of intracellular structures. Over the years, various methods have been evaluated to overcome this issue to explore the full potential of the QDs. Thus, in this review, we focused our attention on physical and biochemical QD delivery methods-electroporation, microinjection, cell-penetrating peptides, molecular coatings, and liposomes-discussing the benefits and drawbacks of each strategy, as well as presenting recent studies in the field. We hope that this review can be a useful reference source for researches that already work or intend to work in this area. Strategies for the intracellular delivery of quantum dots discussed in this review (electroporation, microinjection, cell-penetrating peptides, molecular coatings, and liposomes).

Plasmon-Emitter Hybrid Nanostructures of Gold Nanorod-Quantum Dots with Regulated Energy Transfer as a Universal Nano-Sensor for One-step Biomarker Detection

Recently, biosensing based on weak coupling in plasmon-emitter hybrid nanostructures exhibits the merits of simplicity and high sensitivity, and attracts increasing attention as an emerging nano-sensor. In this study, we propose an innovative plasmon-regulated fluorescence resonance energy transfer (plasmon-regulated FRET) sensing strategy based on a plasmon-emitter hybrid nanostructure of gold nanorod-quantum dots (Au NR-QDs) by partially modifying QDs onto the surfaces of Au NRs. The Au NR-QDs showed good sensitivity and reversibility against refractive index change. We successfully employed the Au NR-QDs to fabricate nano-sensors for detecting a cancer biomarker of alpha fetoprotein with a limit of detection of 0.30 ng/mL, which displays that the sensitivity of the Au NR-QDs nano-sensor was effectively improved compared with the Au NRs based plasmonic sensing. Additionally, to demonstrate the universality of the plasmon-regulated FRET sensing strategy, another plasmon-emitter hybrid nano-sensor of Au nano-prism-quantum dots (Au NP-QDs) were constructed and applied for detecting a myocardial infarction biomarker of cardiac troponin I. It was first reported that the change of absorption spectra of plasmonic structure in a plasmon-emitter hybrid nanostructure was employed for analytes detection. The plasmon-regulated FRET sensing strategy described herein has potential utility to develop general sensing platforms for chemical and biological analysis.

Nucleic Acid Aptamers as a Potential Nucleus Targeted Drug Delivery System

BACKGROUND

Nucleus targeted drug delivery provides several opportunities for the treatment of fatal diseases such as cancer. However, the complex nucleocytoplasmic barriers pose significant challenges for delivering a drug directly and efficiently into the nucleus. Aptamers representing singlestranded DNA and RNA qualify as next-generation highly advanced and personalized medicinal agents that successfully inhibit the expression of certain proteins; possess extraordinary gene-expression for manoeuvring the diseased cell's fate with negligible toxicity. In addition, the precisely directed aptamers to the site of action present a tremendous potential to reach the nucleus by escaping the ensuing barriers to exhibit a better drug activity and gene expression.

OBJECTIVE

This review epigrammatically highlights the significance of targeted drug delivery and presents a comprehensive description of the principal barriers faced by the nucleus targeted drug delivery paradigm and ensuing complexities thereof. Eventually, the progress of nucleus targeting with nucleic acid aptamers and success achieved so far have also been reviewed.

METHODS

Systematic literature search was conducted of research published to date in the field of nucleic acid aptamers.

CONCLUSION

The review specifically points out the contribution of individual aptamers as the nucleustargeting agent rather than aptamers in conjugated form.

The hurdles of nanotoxicity in transplant nanomedicine

Nanomedicine has matured significantly in the past 20 years and a number of nanoformulated therapies are cleared by regulatory agencies for use across the globe. Transplant medicine is one area that has significantly benefited from the advancement of nanomedicine in recent times. However, while nanoparticle-based therapies have improved toxicological profiles of some drugs, there are still a number of aspects regarding the biocompatibility and toxicity of nanotherapies that require further research. The goal of this article is to review toxicological profiles of immunosuppressant therapies and their conversion into nanomedicine formulations as well as introduce future challenges associated with current in vitro and in vivo toxicological models.

Colloidal Nanobioconjugate with Complementary Surface Chemistry for Cellular and Subcellular Targeting

Chemically and biochemically functionalized colloidal nanoparticles with appropriate surface chemistry are essential for various biomedical applications. Although a variety of approaches are now available in making such functional nanoparticles and nanobioconjugates, the lack of complementary surface chemistry often leads to poor performance with respect to intended biomedical applications. This feature article will focus on our efforts to make colloidal nanobioconjugates with appropriate/complementary surface chemistry for better performance of a designed nanoprobe with respect to cellular and subcellular targeting applications. In particular, we emphasize polyacrylate-based coating chemistry followed by a conjugation strategy for transforming <10 nm inorganic nanoparticle to colloidal nanoprobe of 20-50 nm hydrodynamic size. We show that a colloidal nanoprobe can be chemically designed to control the cell-nanoparticle interaction, cellular endocytosis, and targeting/labeling of subcellular compartments. Further study should be directed to adapt this surface chemistry to different nanoparticles, fine tune the surface chemistry for targeting/imaging on the subcellular/molecular length scale, and develop a delivery nanocarrier for subcellular compartments.

Self-Assembled Double-Bundle DNA Tetrahedron for Efficient Antisense Delivery

DNA nanostructures are promising biomaterials capable of arranging multiple functional components with nanometer precision. Here, a double-bundle DNA tetrahedron is rationally designed to integrate with antisense oligonucleotides silencing proto-oncogene c-raf and nuclear targeting peptides. The functionalized DNA tetrahedron can be internalized by A549 cells and assists the delivery of antisense oligonucleotides toward the nucleus to increase the chance to downregulate target mRNA in nucleus and cytoplasm. Antisense strands released from the tetrahedron in response to the intracellular reducing environment can inhibit cell proliferation at a low concentration without transfection reagent. Finally, efficient knockdown of c-raf gene is observed, which verified our design. This designer DNA-based nanocarrier system will open a new avenue for efficient delivery of nucleic acid drugs.

Non-viral delivery systems for CRISPR/Cas9-based genome editing: Challenges and opportunities

In recent years, CRISPR (clustered regularly interspaced short palindromic repeat)/Cas (CRISPR-associated) genome editing systems have become one of the most robust platforms in basic biomedical research and therapeutic applications. To date, efficient in vivo delivery of the CRISPR/Cas9 system to the targeted cells remains a challenge. Although viral vectors have been widely used in the delivery of the CRISPR/Cas9 system in vitro and in vivo, their fundamental shortcomings, such as the risk of carcinogenesis, limited insertion size, immune responses and difficulty in large-scale production, severely limit their further applications. Alternative non-viral delivery systems for CRISPR/Cas9 are urgently needed. With the rapid development of non-viral vectors, lipid- or polymer-based nanocarriers have shown great potential for CRISPR/Cas9 delivery. In this review, we analyze the pros and cons of delivering CRISPR/Cas9 systems in the form of plasmid, mRNA, or protein and then discuss the limitations and challenges of CRISPR/Cas9-based genome editing. Furthermore, current non-viral vectors that have been applied for CRISPR/Cas9 delivery in vitro and in vivo are outlined in details. Finally, critical obstacles for non-viral delivery of CRISPR/Cas9 system are highlighted and promising strategies to overcome these barriers are proposed.

Multifunctional Gene Carriers with Enhanced Specific Penetration and Nucleus Accumulation to Promote Neovascularization of HUVECs in Vivo

Recently, gene therapy has attracted much attention, especially for the treatment of vascular disease. However, it is still challenging to develop the gene carriers with high biocompatibility as well as highly efficient gene delivery to overcome multiple barriers. Herein, a frequently used cell-penetrating peptide PKKKRKV (TAT) was selected as a functional sequence of the gene carrier with distinctive cell-penetrating ability. REDV peptide with selectively targeting function for endothelial cells (ECs) and nuclear localization signals (NLS) were integrated with this TAT peptide to obtain a highly efficient gene delivery system with ECs specificity and nucleus accumulation capacity. Besides, the glycine sequences with different repeat numbers were inserted into the above integrated peptide. These glycine sequences acted as a flexible spacer arm to exert the targeting, cell-penetrating, and nucleus accumulation functions of each functional peptide. Three tandem peptides REDV-G_m-TAT-G_m-NLS (m = 0, 1, and 4) complexed with pZNF580 plasmid to form gene complexes. The results of hemocompatibility and cytocompatibility indicated that these peptides and gene complexes were nontoxic and biocompatible. The internalization efficiency and mechanism of these gene complexes were investigated. The internalization efficiency was improved as the introduction of targeting REDV and glycine sequence, and the REDV-G₄-TAT-G₄-NLS/pZNF580 (TP-G4/pZNF580) complexes showed the highest cellular uptake among the gene complexes. The TP-G4/pZNF580 complexes also presented significantly higher internalization efficiency (∼1.36 times) in human umbilical vein endothelial cells (HUVECs) than human umbilical artery smooth muscle cells. TP-G4/pZNF580 complexes substantially promoted the expression of pZNF580 by confocal live cell imaging, gene delivery efficiency, and HUVECs migration assay. The in vitro and in vivo revascularization ability of transfected HUVECs was further enhanced obviously. In conclusion, these multifunctional REDV-G_m-TAT-G_m-NLS peptides offer a promising and efficacious delivery option for neovascularization to treat vascular diseases.

Simultaneous Gene Delivery and Tracking through Preparation of Photo-Luminescent Nanoparticles Based on Graphene Quantum Dots and Chimeric Peptides

Designing suitable nano-carriers for simultaneous gene delivery and tracking is in the research priorities of the molecular medicine. Non-toxic graphene quantum dots (GQDs) with two different (green and red) emission colors are synthesized by Hummer's method and characterized by UV-Vis, Photoluminescence (PL), Fourier Transform Infrared (FTIR) and Raman spectroscopies, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The GQDs are conjugated with MPG-2H1 chimeric peptide and plasmid DNA (pDNA) by non-covalent interactions. Following conjugation, the average diameter of the prepared GQDs increased from 80 nm to 280 nm in complex structure, and the ζ-potential of the complex increased (from -36.87 to -2.56 mV). High transfection efficiency of the nano-carrier and results of confocal microscopy demonstrated that our construct can be considered as a nontoxic carrier with dual functions for gene delivery and nuclear targeting.

The role of intracellular trafficking of CdSe/ZnS QDs on their consequent toxicity profile

Background

Nanoparticle interactions with cellular membranes and the kinetics of their transport and localization are important determinants of their functionality and their biological consequences. Understanding these phenomena is fundamental for the translation of such NPs from in vitro to in vivo systems for bioimaging and medical applications. Two CdSe/ZnS quantum dots (QD) with differing surface functionality (NH₂ or COOH moieties) were used here for investigating the intracellular uptake and transport kinetics of these QDs.

Results

In water, the COOH- and NH₂-QDs were negatively and positively charged, respectively, while in serum-containing medium the NH₂-QDs were agglomerated, whereas the COOH-QDs remained dispersed. Though intracellular levels of NH₂- and COOH-QDs were very similar after 24 h exposure, COOH-QDs appeared to be continuously internalised and transported by endosomes and lysosomes, while NH₂-QDs mainly remained in the lysosomes. The results of (intra)cellular QD trafficking were correlated to their toxicity profiles investigating levels of reactive oxygen species (ROS), mitochondrial ROS, autophagy, changes to cellular morphology and alterations in genes involved in cellular stress, toxicity and cytoskeletal integrity. The continuous flux of COOH-QDs perhaps explains their higher toxicity compared to the NH₂-QDs, mainly resulting in mitochondrial ROS and cytoskeletal remodelling which are phenomena that occur early during cellular exposure.

Conclusions

Together, these data reveal that although cellular QD levels were similar after 24 h, differences in the nature and extent of their cellular trafficking resulted in differences in consequent gene alterations and toxicological effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-017-0279-0) contains supplementary material, which is available to authorized users.

Intracellular localisation of proteins to specific cellular areas by nanocapsule mediated delivery

Nanocapsules are promising carriers with great potential for intracellular protein transport. Although many studies have intended to improve cell uptake efficacy, there is an increasing interest in understanding of subcellular distribution of cargoes inside cells, which is essential for purposeful delivery of biomolecules into specific sites within cells. Herein, we interrogate the intracellular localisation of exogenous proteins, including fluorescein isothiocyanate (FITC)-labelled bovine serum albumin (BSA) and green fluorescent protein (GFP), mediated by specially designed nanocapsules. The results show that the designed nanocapsules can deliver the two types of fluorescent proteins into different cellular destinations (cytosol, nucleus or the whole cell), depending on the composition of nanocapsules. Meanwhile, several impact factors that influence the distribution of proteins in cells have also been investigated, and the results suggest that the localisation of capsule-mediated proteins in cells is strongly affected by the surface properties of nanocapsules, the types of stabilisers and proteins, and environmental temperatures. The rational control of intracellular localised delivery of exogenous proteins as we demonstrated in this study might open new avenues to obtain desired magnitude of drug effects for modulating cell activity.

Direct Cytoplasmic Delivery and Nuclear Targeting Delivery of HPMA-MT Conjugates in a Microtubules Dependent Fashion

As the hearts of tumor cells, the nucleus is the ultimate target of many chemotherapeutic agents and genes. However, nuclear drug delivery is always hampered by multiple intracellular obstacles, such as low efficiency of lysosome escape and insufficient nuclear trafficking. Herein, an N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-based drug delivery system was designed, which could achieve direct cytoplasmic delivery by a nonendocytic pathway and transport into the nucleus in a microtubules dependent fashion. A special targeting peptide (MT), derived from an endogenic parathyroid hormone-related protein, was conjugated to the polymer backbone, which could accumulate into the nucleus a by microtubule-mediated pathway. The in vitro studies found that low temperature and NaN3 could not influence the cell internalization of the conjugates. Besides, no obvious overlay of the conjugates with lysosome demonstrated that the polymer conjugates could enter the tumor cell cytoplasm by a nonendocytic pathway, thus avoiding the drug degradation in the lysosome. Furthermore, after suppression of the microtubule dynamics with microtubule stabilizing docetaxel (DTX) and destabilizing nocodazole (Noc), the nuclear accumulation of polymeric conjugates was significantly inhibited. Living cells fluorescence recovery after photobleaching study found that the nuclear import rate of conjugates was 2-fold faster compared with the DTX and Noc treated groups. These results demonstrated that the conjugates transported into the nucleus in a microtubules dependent way. Therefore, in addition to direct cytoplasmic delivery, our peptide conjugated polymeric platform could simultaneously mediate nuclear drug accumulation, which may open a new path for further intracellular genes/peptides delivery.