Polymeric materials for theranostic applications

Discovery and Feasibility Study of Medical Fluorophore 33 as a Novel Theranostic Agent

Fluorescent dyes have garnered significant attention as theranostic platforms owing to their inherent characteristics. In this study, we present the discovery of Medical Fluorophore 33 (MF33), a novel and potent theranostic agent with a phenaleno-isoquinolinium salt structure that can serve as a cancer therapeutic strategy. The synthesis of MF33 is readily achievable through a simple Rh(III)-catalyzed reaction. Moreover, MF33 displayed strong fluorescence signals, excellent microsomal stability, and high biocompatibility in vivo. It induces significant apoptosis in cancer cells via the p53/p21/caspase-3 signaling pathway, leading to selective cytotoxicity in various cancer cells. In vivo fluorescence imaging with MF33 enabled the visualization of sentinel lymph nodes in living mice. Notably, repeated intraperitoneal administration of MF33 resulted in antitumor activity in mice with colorectal cancer. Collectively, our findings suggest that phenaleno-isoquinolinium salt-based MF33 is a viable theranostic agent for biomedical imaging and cancer treatment.

Tailoring Polymer-Based Nanoassemblies for Stimuli-Responsive Theranostic Applications

Polymer assemblies on the nanoscale represent a powerful toolbox for the design of theranostic systems when combined with both therapeutic compounds and diagnostic reporting ones. Here, recent advances in the design of theranostic systems for various diseases, containing-in their architecture-either polymers or polymer assemblies as one of the building blocks are presented. This review encompasses the general principles of polymer self-assembly, from the production of adequate copolymers up to supramolecular assemblies with theranostic functionality. Such polymer nanoassemblies can be further tailored through the incorporation of inorganic nanoparticles to endow them with multifunctional therapeutic and/or diagnostic features. Systems that change their architecture or properties in the presence of stimuli are selected, as responsivity to changes in the environment is a key factor for enhancing efficiency. Such theranostic systems are based on the intrinsic properties of copolymers or one of the other components. In addition, systems with a more complex architecture, such as multicompartments, are presented. Selected systems indicate the advantages of such theranostic approaches and provide a basis for further developments in the field.

Exploring new Horizons in overcoming P-glycoprotein-mediated multidrug-resistant breast cancer via nanoscale drug delivery platforms

The high probability (13%) of women developing breast cancer in their lifetimes in America is exacerbated by the emergence of multidrug resistance after exposure to first-line chemotherapeutic agents. Permeation glycoprotein (P-gp)-mediated drug efflux is widely recognized as the major driver of this resistance. Initial in vitro and in vivo investigations of the co-delivery of chemotherapeutic agents and P-gp inhibitors have yielded satisfactory results; however, these results have not translated to clinical settings. The systemic delivery of multiple agents causes adverse effects and drug-drug interactions, and diminishes patient compliance. Nanocarrier-based site-specific delivery has recently gained substantial attention among researchers for its promise in circumventing the pitfalls associated with conventional therapy. In this review article, we focus on nanocarrier-based co-delivery approaches encompassing a wide range of P-gp inhibitors along with chemotherapeutic agents. We discuss the contributions of active targeting and stimuli responsive systems in imparting site-specific cytotoxicity and reducing both the dose and adverse effects.

Stimuli-Responsive Polymeric Nanoplatforms for Cancer Therapy

Polymeric nanoparticles have been widely used as carriers of drugs and bioimaging agents due to their excellent biocompatibility, biodegradability, and structural versatility. The principal application of polymeric nanoparticles in medicine is for cancer therapy, with increased tumor accumulation, precision delivery of anticancer drugs to target sites, higher solubility of pharmaceutical properties and lower systemic toxicity. Recently, the stimuli-responsive polymeric nanoplatforms attracted more and more attention because they can change their physicochemical properties responding to the stimuli conditions, such as low pH, enzyme, redox agents, hypoxia, light, temperature, magnetic field, ultrasound, and so on. Moreover, the unique properties of stimuli-responsive polymeric nanocarriers in target tissues may significantly improve the bioactivity of delivered agents for cancer treatment. This review introduces stimuli-responsive polymeric nanoparticles and their applications in tumor theranostics with the loading of chemical drugs, nucleic drugs and imaging molecules. In addition, we discuss the strategy for designing multifunctional polymeric nanocarriers and provide the perspective for the clinical applications of these stimuli-responsive polymeric nanoplatforms.

A mechanistic insight into benefits of aggregation induced emissive luminogens in cancer

Exploration of advanced chemotheranostics that benefit from a combined in vivo strategy of cancer diagnosis and chemotherapy simultaneously is highly valued and will expose novel possibilities in modifying treatment and reduce side effects. In recent years, nanodrug delivery systems that incorporate aggregation-induced emissive luminogens (AIEgens) have been developed to track and monitor anticancer drug release, trace translocation processes and predict chemotherapeutic responses. There are several classes of AIEgen based chemotheranostics such us stimuli-responsive nanoprodrugs, pH-sensitive mesoporous silica nanocarriers, supramolecular polymer systems, drug encapsulated carriers, carrier-free nanodrugs, self-indicating drug delivery nanomachines and AIEgen-prodrug co-assembly. The present review conveys mechanistic insight into the benefits of AIEgens in the theranostic application by illustrating the recent breakthroughs in chemotheranostic nanomedicines that incorporate these unique fluorophores as signal reporters. The perspectives that can be further explored are also highlighted with the hope to instil more research interest in the advancement of AIE active cancer chemotheranostics for imaging and treatment in vivo.HIGHLIGHTSAggregation induced emissive materials (AIEgens) exhibit unique advantages over conventional luminogens for synergistic diagnosis and chemotherapy of cancer in vivo.The combination of AIE and nanotechnology offers an excellent platform to fabricate advanced chemotheranostics for cancer therapy.

Synthesis of Water-Soluble Copolymers of N-vinylpyrrolidone with N-vinyldithiocarbamate as Multidentate Polymeric Chelation Systems and Their Complexes with Indium and Gallium

Dithiocarbamate (DTC) derivatives of N-vinylpyrrolidone-N-vinylamine (VP–VA) copolymers were synthesized via reaction between the copolymers and carbon disulfide in alkaline medium; molecular masses of the products were 12 and 29 kDa; the VP:VDTC ratios were 94:6 and 83:17 mol.%. Complexation between the obtained DTC derivatives and metal ions (indium and gallium) was investigated. It was demonstrated that metal–DTC ligand complexes with 1:3 ratio between components were formed. Gallium metal–polymer complexes (MPC) were unstable in solution. Individual indium MPC were isolated and characterized by spectral and chromatographic methods. Unlike similar gallium MPC, they appeared to be stable in histidine challenge reaction.

Biodegradable and biocompatible spherical dendrimer nanoparticles with a gallic acid shell and a double-acting strong antioxidant activity as potential device to fight diseases from "oxidative stress"

Gallic acid (GA) is a natural polyphenol with remarkable antioxidant power present in several vegetables and fruits. A normal feeding regime leads to a daily intake of GA which is reasonably regarded as "natural" and "safe" for humans. It owns strong potentials as alternative to traditional drugs to treat several diseases triggered by oxidative stress (OS), but poor gastrointestinal absorbability, pharmacokinetic drawbacks, and fast metabolism limit its clinical application. In this work, a fifth-generation polyester-based dendrimer was firstly prepared as a better absorbable carrier to protect and deliver GA. Then, by its peripheral esterification with GA units, a GA-enriched delivering system (GAD) with remarkable antioxidant power and high potential against diseases from OS was achieved. Scanning electron microscopy results and dynamic light scattering analysis revealed particles with an average size around 387 and 375 nm, respectively, and an extraordinarily spherical morphology. These properties, by determining a large particles surface area, typically favour higher systemic residence time and bio-efficiency. Z-potential of - 25 mV suggests satisfactory stability in solution with tendency to form megamers and low polydispersity index. GAD showed intrinsic antioxidant power, higher than GA by 4 times and like prodrugs, and it can carry contemporary several bioactive GA units versus cells. In physiological condition, the action of pig liver esterase (PLE), selected as a model of cells esterase, hydrolyses GAD to non-cytotoxic small molecules, thus setting free the bioactive GA units, for further antioxidant effects. Cytotoxicity studies performed on two cell lines demonstrated a high cell viability. Graphical Abstract Graphical Abstract.

Dual-pH Sensitive Charge-Reversal Drug Delivery System for Highly Precise and Penetrative Chemotherapy

PURPOSE

The complex physiological barriers impose extremely conflicting demands on systemic drug delivery, so both particle size and surface charge of the nanoplatforms become vital factors. As a carbon-based nanomaterial with excellent optical properties, carbon dots are not suitable for direct systemic transport in vivo, which limits their application in the field of biomedical imaging, especially in the areas of diagnosis and cancer treatment. Liposomes have been developed as universal nanocarriers for various drugs. In this study, we aimed to build a highly precise and penetrative drug delivery system (DDS) using carbon dots encapsulated by liposomes.

METHODS

Carbon dots (CDs) were synthesized by the hydrothermal method using citric acid and ethylenediamine. Furthermore, simian virus 40 large T-antigen derived the nuclear targeting sequence (NLS) was bonded on the surface of CDs to obtain CDs-NLS. The antitumor drug doxorubicin was loaded onto the CDs-NLS through an acid-labile hydrazine bond to obtain DOX@CDs. Finally, DOX@CDs were encapsulated in aqueous centers of folate-coated and pH-sensitive liposomes, named pHSL-FA.

RESULTS

In this paper, a nucleus-targeted nanocomposite (DOX@CDs), which bonds with the nuclear targeting sequence (NLS) and the anticancer drug doxorubicin (DOX), has physicochemical properties of particle size of about 3.8 nm, zeta potential of +31.8 mV and high quantum yield of 64.53%. The negatively charged folate-coated and pH-sensitive liposomes (pHSL-FA) are used as a carrier to reverse the surface charge of DOX@CDs. Compared to free DOX@CDs, pHSL-FA show higher tumor accumulation in 4 T1 tumor-bearing mice and further improve cytotoxicity to tumor cells.

CONCLUSIONS

This work proposes a unique nanomedical approach that enables the precise delivery of chemotherapy drugs and significantly reduces side effects, which is promising for clinical translation.

Recent advances in theranostic polymeric nanoparticles for cancer treatment: A review

Nanotheranostics is fast-growing pharmaceutical technology for simultaneously monitoring drug release and its distribution, and to evaluate the real time therapeutic efficacy through a single nanoscale for treatment and diagnosis of deadly disease such as cancers. In recent two decades, biodegradable polymers have been discovered as important carriers to accommodate therapeutic and medical imaging agents to facilitate construction of multi-modal formulations. In this review, we summarize various multifunctional polymeric nano-sized formulations such as polymer-based super paramagnetic nanoparticles, ultrasound-triggered polymeric nanoparticles, polymeric nanoparticles bearing radionuclides, and fluorescent polymeric nano-sized formulations for purpose of theranostics. The use of such multi-modal nano-sized formulations for near future clinical trials can assist clinicians to predict therapeutic properties (for instance, depending upon the quantity of drug accumulated at the cancerous site) and observed the progress of tumor growth in patients, thus improving tailored medicines.

Polyester-Based Dendrimer Nanoparticles Combined with Etoposide Have an Improved Cytotoxic and Pro-Oxidant Effect on Human Neuroblastoma Cells

Etoposide (ETO) is a cytotoxic drug that exerts its effect by increasing reactive oxygen species (ROS) production. Although ETO is widely used, fast metabolism, poor solubility, systemic toxicity, and multi-drug resistance induction all limit its administration dosage and its therapeutic efficiency. In order to address these issues, a biodegradable dendrimer was prepared for entrapping and protecting ETO and for enhancing its solubility and effectiveness. The achieved dendrimer complex with ETO (CPX 5) showed the typical properties of a well-functioning delivery system, i.e., nanospherical morphology (70 nm), optimal Z-potential (-45 mV), good drug loading (37%), very satisfying entrapment efficiency (53%), and a remarkably improved solubility in biocompatible solvents. In regards to its cytotoxic activity, CPX 5 was tested on neuroblastoma (NB) cells with very promising results. In fact, the dendrimer scaffold and ETO are able to exert per se a cytotoxic and pro-oxidant activity on human NB cells. When CPX 5 is combined with ETO, it shows a synergistic action, slowly releasing the drug over time and significantly improving and protracting bioactivity. On the basis of these findings, the prepared ETO reservoir represents a novel biodegradable and promising device for the delivery of ETO into NB cells.

Nanocomposites as biomolecules delivery agents in nanomedicine

Nanoparticles (NPs) are atomic clusters of crystalline or amorphous structure that possess unique physical and chemical properties associated with a size range of between 1 and 100 nm. Their nano-sized dimensions, which are in the same range as those of vital biomolecules, such as antibodies, membrane receptors, nucleic acids, and proteins, allow them to interact with different structures within living organisms. Because of these features, numerous nanoparticles are used in medicine as delivery agents for biomolecules. However, off-target drug delivery can cause serious side effects to normal tissues and organs. Considering this issue, it is essential to develop bioengineering strategies to significantly reduce systemic toxicity and improve therapeutic effect. In contrast to passive delivery, nanosystems enable to obtain enhanced therapeutic efficacy, decrease the possibility of drug resistance, and reduce side effects of "conventional" therapy in cancers. The present review provides an overview of the most recent (mostly last 3 years) achievements related to different biomolecules used to enable targeting capabilities of highly diverse nanoparticles. These include monoclonal antibodies, receptor-specific peptides or proteins, deoxyribonucleic acids, ribonucleic acids, [DNA/RNA] aptamers, and small molecules such as folates, and even vitamins or carbohydrates.

Facile Preparation of Reduction-Responsive Micelles Based on Biodegradable Amphiphilic Polyurethane with Disulfide Bonds in the Backbone

In this paper, we synthesized a biodegradable amphiphilic polymer of polyurethane-polyethylene glycol with disulfide bonds in the main chain (PEG-PU(SS)-PEG). DLS and SEM showed that the polymer could self-assemble into micelles in aqueous solution and could be used to load the hydrophobic anticancer drug DOX. Intriguingly, drug release in vitro indicated that DOX-loaded PEG-PU(SS)-PEG micelles had good stability under the extracellular physiological environment, but the disulfide bonds broke rapidly and DOX was released quickly under the intracellular reducing conditions. CCK-8 assays showed that DOX-loaded PEG-PU(SS)-PEG micelles had a high in vitro antitumor activity in C6 cells, whereas blank PEG-PU(SS)-PEG micelles were nontoxic to C6 cells. It was also found that there was strong and persistent accumulation of DOX-loaded PEG-PU(SS)-PEG as compared with PEG-PU-PEG both by the cell internalization tests and the flow cytometry measurements. Hence, PEG-PU(SS)-PEG micelles will have a potential use for clinical treatment of cancer in the future.

Preparation of ellagic acid micro and nano formulations with amazingly increased water solubility by its entrapment in pectin or non-PAMAM dendrimers suitable for clinical applications

Innovative antioxidant ellagic acid (EA) formulations suitable for oral and parenteral EA administration were achieved avoiding the use of harmful additives.

Dendrimer- and copolymer-based nanoparticles for magnetic resonance cancer theranostics

Cancer theranostics is one of the most important approaches for detecting and treating patients at an early stage. To develop such a technique, accurate detection, specific targeting, and controlled delivery are the key components. Various kinds of nanoparticles have been proposed and demonstrated as potential nanovehicles for cancer theranostics. Among them, polymer-like dendrimers and copolymer-based core-shell nanoparticles could potentially be the best possible choices. At present, magnetic resonance imaging (MRI) is widely used for clinical purposes and is generally considered the most convenient and noninvasive imaging modality. Superparamagnetic iron oxide (SPIO) and gadolinium (Gd)-based dendrimers are the major nanostructures that are currently being investigated as nanovehicles for cancer theranostics using MRI. These structures are capable of specific targeting of tumors as well as controlled drug or gene delivery to tumor sites using pH, temperature, or alternating magnetic field (AMF)-controlled mechanisms. Recently, Gd-based pseudo-porous polymer-dendrimer supramolecular nanoparticles have shown 4-fold higher T1 relaxivity along with highly efficient AMF-guided drug release properties. Core-shell copolymer-based nanovehicles are an equally attractive alternative for designing contrast agents and for delivering anti-cancer drugs. Various copolymer materials could be used as core and shell components to provide biostability, modifiable surface properties, and even adjustable imaging contrast enhancement. Recent advances and challenges in MRI cancer theranostics using dendrimer- and copolymer-based nanovehicles have been summarized in this review article, along with new unpublished research results from our laboratories.

Preparation of poly-l-lysine-based nanoparticles with pH-sensitive release of curcumin for targeted imaging and therapy of liver cancer in vitro and in vivo

Poly-l-lysine (PLL) nanoparticle (NP) system was prepared for the controlled release of curcumin (CUR) by pH stimuli, and its theranostic efficacy on cancer was compared to that of CUR solution in vitro and in vivo. Deoxycholic acid (DOCA), methoxy polyethylene glycol (MPEG) and cyanine 5.5 (cy5.5) were conjugated to the amine group of PLL through condensation reaction (PLL-DOCA-MPEG-cy5.5), followed by encapsulation of CUR by dialysis method (PLL-DOCA-MPEG-cy5.5/CUR NPs). The composition, morphology and size distribution of PLL-DOCA-MPEG-cy5.5 NPs were characterized by proton nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. In vitro tests exhibited that changes in the charge and size of the NPs at low pH led to the improved cellular uptake of CUR into human hepatoma Hep3B cell line by electrostatically absorptive endocytosis. PEGylation with MPEG was turn out to be very effective to have a prolonged blood circulation time, in turn increased the EPR effect. In addition, the incorporation of Cy5.5 into NPs provided successful biodistribution images in vivo and ex vivo. Our findings suggest that PLL-DOCA-MPEG-cy5.5/CUR NPs may have promising applications in cancer theranosis.

Theranostics based on AIEgens

The utilization of luminogens with aggregation-induced emission (AIE) characteristics has recently been developed at a tremendous pace in the area of theranostics, mainly because AIE luminogens (AIEgens) hold various distinct advantages, such as good biocompatibility, excellent fluorescence properties, simple preparation and modification, perfect size of nano-aggregation for enhanced permeability and retention effect, promoted efficiencies of photodynamic and photothermal therapies, efficient photoacoustic imaging, and ready constructions of multimodal imaging and therapy. Significant breakthroughs and developments of theranostics based on AIEgens have been achieved in the past few years, and great progress has been witnessed in many theranostic modalities, indicating that AIEgens remarkably complement conventional theranostic materials and promote the development of theranostics. This review provides theoretical insights into the advantages of AIEgens in theranostics, and systematically summarizes the basic concepts, seminal studies, recent trends and perspectives in theranostics based on AIEgens. We believe that AIEgens would be promising multifunctional theranostic platforms in clinical fields and facilitate significant advancements in this research-active area.

Hydrophilic and amphiphilic water-soluble dendrimer prodrugs suitable for parenteral administration of a non-soluble non-nucleoside HIV-1 reverse transcriptase inhibitor thiocarbamate derivative

Drugs delivered by proper carriers enter into the cells much more rapidly and carry out their action much more promptly than in the free forms. A high drug concentration can be sustained for longer periods of time at the target site in the cell. In in vivo conditions, this would translate into a reduction of systemic toxicity, dosage and frequency of dosing. Dendritic polymers significantly affect drug delivery in terms of reaching the target site, modifying the bio-distribution of the drug, and enhancing the efficacy of different drugs including anticancer compounds. 2-({[2-({[(2-tolyl)amino]carbonothioyl}oxy)ethyl]amino}carbo-nyl)benzoic acid 1 is a thiocarbamate derivative belonging to an already reported class of non-nucleoside HIV-1 reverse transcriptase inhibitors. In in vitro assay it showed no cytotoxic effects but was endowed with very low solubility and poor activity against wild-type HIV-1 (EC₅₀ = 27 μM). With the aim at improving its water solubility, 1 has been successfully incorporated inside non-toxic amino acids-modified core-shell hetero dendrimers. IR, NMR, zeta potential, mean size of particles, buffer capacity and in vitro release profile of prepared materials were reported. All dendriplexes were evaluated in cell-based assays to assess their cytotoxic profile. The obtained complexes, which harmonize a peripheral polycationic character and a buffer capacity which presuppose efficient cells penetration and increased residence time with a not PAMAM structured biodegradable scaffold, were well water-soluble and could rationally appear as a promising set of prodrugs for safe in vivo administrations.

Probing Cellular Processes Using Engineered Nanoparticles

Nanoparticles, the building blocks of nanotechnology, have been widely utilized in various biomedical applications, such as detection, diagnosis, imaging, and therapy. However, another emerging, albeit under-represented, area is the employment of nanoparticles as tools to understand cellular processes (e.g., oxidative stress-induced signaling cascades). Such investigations have enormous potential to characterize a disease from a different perspective and unravel some new features that otherwise would have remained a mystery. In this review, we summarize the intrinsic biological properties of unmodified as well surface modified nanoparticles and discuss how such properties could be utilized to interrogate biological processes and provide a perspective for future evolution of this field.

Theranostic Nanoparticles for Tracking and Monitoring Disease State

The development of novel nanoparticles consisting of both diagnostic and therapeutic components has increased over the past decade. These "theranostic" nanoparticles have been tailored toward one or more types of imaging modalities and have been developed for optical imaging, magnetic resonance imaging, ultrasound, computed tomography, and nuclear imaging comprising both single-photon computed tomography and positron emission tomography. In this review, we focus on state-of-the-art theranostic nanoparticles that are capable of both delivering therapy and self-reporting/tracking disease through imaging. We discuss challenges and the opportunity to rapidly adjust treatment for individualized medicine.

Metal ion assisted interface re-engineering of a ferritin nanocage for enhanced biofunctions and cancer therapy

The bottom-up self-assembly of protein subunits into supramolecular nanoarchitectures is ubiquitously exploited to recapitulate and expand the features of natural proteins to advance nanoscience in medicine. Various chemical and biological re-engineering approaches are available to render diverse functions in the given proteins. They are, unfortunately, capable of compromising protein integrity and stability after extensive modifications. In this study, we introduce a new protein re-engineering method, metal ion assisted interface re-engineering (MAIR), to serve as a robust and universal strategy to extend the functions of self-assembly proteins by boosting structural features to advance their diverse biomedical applications. In particular, the MAIR strategy was applied to a widely used natural protein, ferritin, as a model protein to coordinate with copper ions in its mutagenic artificial metal binding domain. Structure directed rational protein mutagenesis was carried out at the C2 interface amino acid residues of the ferritin subunit for metal ion coordination site optimization. Copper binding at the artificial binding pocket was highly specific over the other divalent ions present in physiological fluids, and the structurally embedded copper ion in turn strengthened the overall protein integrity and stability. In the presence of isotopic copper-64, the interface re-engineered ferritin worked as a chelator-free molecular nanoprobe with an extraordinarily high specific activity to allow PET imaging of tumors in live animals. We also found that the re-engineered ferritin coordinating with copper ions demonstrates high drug loading capacity of a widely used anti-cancer agent, doxorubicin (DOX), to achieve significant drug retention at the tumor site and enhance tumor regression for improved anti-cancer effects. The MAIR approach, thus, exploited the copper ion to facilitate efficient one-step labeling of mutant ferritin derivatives for simultaneous molecular imaging and drug delivery. The reported interface re-engineering strategy provides an unparalleled opportunity to expand protein biofunctions to serve as a new theranostic agent in cancer research.

Cancer-Associated, Stimuli-Driven, Turn on Theranostics for Multimodality Imaging and Therapy

Advances in bioinformatics, genomics, proteomics, and metabolomics have facilitated the development of novel anticancer agents that have decreased side effects and increased safety. Theranostics, systems that have combined therapeutic effects and diagnostic capabilities, have garnered increasing attention recently because of their potential use in personalized medicine, including cancer-targeting treatments for patients. One interesting approach to achieving this potential involves the development of cancer-associated, stimuli-driven, turn on theranostics. Multicomponent constructs of this type would have the capability of selectively delivering therapeutic reagents into cancer cells or tumor tissues while simultaneously generating unique signals that can be readily monitored under both in vitro and in vivo conditions. Specifically, their combined anticancer activities and selective visual signal respond to cancer-associated stimuli, would make these theranostic agents more highly efficient and specific for cancer treatment and diagnosis. This article focuses on the progress of stimuli-responsive turn on theranostics that activate diagnostic signals and release therapeutic reagents in response to the cancer-associated stimuli. The present article not only provides the fundamental backgrounds of diagnostic and therapeutic tools that have been widely utilized for developing theranostic agents, but also discusses the current approaches for developing stimuli-responsive turn on theranostics.

Li+ activated nanohydroxyapatite doped with Eu3+ ions enhances proliferative activity and viability of human stem progenitor cells of adipose tissue and olfactory ensheathing cells. Further perspective of nHAP:Li+, Eu3+ application in theranostics

Spinal cord injuries (SCI) often require simultaneous regeneration of nerve tissue and bone. Hydroxyapatites are described as bioresorbable materials with proper biocompatibility and osteoconductivity, therefore its application for spinal surgery is considered. In this paper, we present repeatable method for developing nanocrystalline calcium hydroxyapatites structurally modified with Li⁺ ions (nHAP:Li⁺). Obtained biomaterials were profoundly characterized in terms of their physicochemical properties. Moreover, we have shown that nHAP:Li⁺ doped with europium (Eu³⁺) may serve as a theranostic agent, what additionally extend its potential usage for SCI treatment. The biocompatibility of nHAP:Li⁺ was determined using human olfactory ensheathing cells (hOECs) and adipose tissue-derived multipotent stromal cells (hASCs). Both population of cells are eagerly applied for cell-based therapies in SCI, mainly due to their paracrine activity. The extensive in vitro studies showed that nHAP:Li⁺ promotes the cells proliferation, viability and cell-cell interactions. Obtained results provides encouraging approach that may have potential application in regenerative medicine and that could fulfil the promise of personalized medicine - important in SCI treatment.

Recent strategies to design vascular theranostic nanoparticles

Vascular disease is a leading cause of death and disability worldwide. Current surgical intervention and treatment options for vascular diseases have exhibited limited long-term success, emphasizing the need to develop advanced treatment paradigms for early detection and more effective treatment of dysfunctional cells in a specific blood vessel lesion. Advances in targeted nanoparticles mediating cargo delivery enables more robust prevention, screening, diagnosis, and treatment of vascular disorders. In particular, nanotheranostics integrates diagnostic imaging and therapeutic function into a single agent, and is an emerging platform towards more effective and localized vascular treatment. This review article highlights recent advances and current challenges associated with the utilization of targeted nanoparticles for real-time diagnosis and treatment of vascular diseases. Given recent developments, nanotheranostics offers great potential to serve as an effective platform for targeted, localized, and personalized vascular treatment.

Nanoparticles as safe and effective delivery systems of antifungal agents: Achievements and challenges

Invasive fungal infections are becoming a major health concern in several groups of patients leading to severe morbidity and mortality. Moreover, cutaneous fungal infections are a major cause of visits to outpatient dermatology clinics. Despite the availability of several effective agents in the antifungal drug arena, their therapeutic outcome is less than optimal due to limitations related to drug physicochemical properties and toxicity. For instance, poor aqueous solubility limits the formulation options and efficacy of several azole antifungal drugs while toxicity limits the benefits of many other drugs. Nanoparticles hold great promise to overcome these limitations due to their ability to enhance drug aqueous solubility, bioavailability and antifungal efficacy. Further, drug incorporation into nanoparticles could greatly reduce its toxicity. Despite these interesting nanoparticle features, there are only few marketed nanoparticle-based antifungal drug formulations. This review sheds light on different classes of nanoparticles used in antifungal drug delivery, such as lipid-based vesicles, polymeric micelles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and dendrimers with emphasis on their advantages and limitations. Translation of these nanoformulations from the lab to the clinic could be facilitated by focusing the research on overcoming problems related to nanoparticle stability, drug loading and high cost of production and standardization.

Gadolinium functionalized carbon dots for fluorescence/magnetic resonance dual-modality imaging of mesenchymal stem cells

The development of multimodal nanoprobes is of great importance in nanomedicine because it integrates the advantages of each imaging modality and offers a significantly enhanced diagnostic effect. In this work, gadolinium(iii) functionalized fluorescent carbon dots (Gd-CDs) are synthesized by means of a one-step hydrothermal approach. As a fluorescent nanomaterial, the obtained Gd-CDs exhibit strong and stable fluorescence with excitation-independent emission behavior. Moreover, as an MRI contrast agent, the Gd-CDs exhibited a longitudinal relaxation rate of 6.06 mM^-1 s^-1, which is significantly higher than that of the commercially available MRI agent Gadovist (4.24 mM^-1 s^-1). In addition, the cellular experiment reveals that Gd-CDs promote the proliferation of human mesenchymal stem cells (hMSCs), which is tracked by the fluorescence/Magnetic Resonance dual-modality imaging of hMSCs by the Gd-CDs.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Coarse-grained model of adsorption of blood plasma proteins onto nanoparticles

We present a coarse-grained model for evaluation of interactions of globular proteins with nanoparticles (NPs). The protein molecules are represented by one bead per aminoacid and the nanoparticle by a homogeneous sphere that interacts with the aminoacids via a central force that depends on the nanoparticle size. The proposed methodology is used to predict the adsorption energies for six common human blood plasma proteins on hydrophobic charged or neutral nanoparticles of different sizes as well as the preferred orientation of the molecules upon adsorption. Our approach allows one to rank the proteins by their binding affinity to the nanoparticle, which can be used for predicting the composition of the NP-protein corona. The predicted ranking is in good agreement with known experimental data for protein adsorption on surfaces.

Supramolecular PEGylated Dendritic Systems as pH/Redox Dual-Responsive Theranostic Nanoplatforms for Platinum Drug Delivery and NIR Imaging

Recently, self-assembling small dendrimers into supramolecular dendritic systems offers an alternative strategy to develop multifunctional nanoplatforms for biomedical applications. We herein report a dual-responsive supramolecular PEGylated dendritic system for efficient platinum-based drug delivery and near-infrared (NIR) tracking. With a refined molecular/supramolecular engineering, supramolecular dendritic systems were stabilized by bioreducible disulfide bonds and endowed with NIR fluorescence probes, and PEGylated platinum derivatives coordinated onto the abundant peripheral groups of supramolecular dendritic templates to generate pH/redox dual-responsive theranostic supramolecular PEGylated dendritic systems (TSPDSs). TSPDSs markedly improved the pharmacokinetics and biodistribution of platinum-based drugs, owing to their stable nanostructures and PEGylated shells during the blood circulation. Tumor intracellular environment (low pH value and high glutathione concentration) could trigger the rapid disintegration of TSPDSs due to acid-labile coordination bonds and redox-cleavable disulfide linkages, and then platinum-based drugs were delivered into the nuclei to exert antitumor activity. In vivo antitumor treatments indicated TSPDSs not only provided high antitumor efficiency which was comparable to clinical cisplatin, but also reduced renal toxicity of platinum-based drugs. Moreover, NIR fluorescence of TSPDSs successfully visualized in vitro and in vivo fate of nanoplatforms and disclosed the intracellular platinum delivery and pharmacokinetics. These results confirm tailor-made supramolecular dendritic system with sophisticated nanostructure and excellent performance is a promising candidate as smart theranostic nanoplatforms.

Nanoparticles and DNA - a powerful and growing functional combination in bionanotechnology

Functionally integrating DNA and other nucleic acids with nanoparticles in all their different physicochemical forms has produced a rich variety of composite nanomaterials which, in many cases, display unique or augmented properties due to the synergistic activity of both components. These capabilities, in turn, are attracting greater attention from various research communities in search of new nanoscale tools for diverse applications that include (bio)sensing, labeling, targeted imaging, cellular delivery, diagnostics, therapeutics, theranostics, bioelectronics, and biocomputing to name just a few amongst many others. Here, we review this vibrant and growing research area from the perspective of the materials themselves and their unique capabilities. Inorganic nanocrystals such as quantum dots or those made from gold or other (noble) metals along with metal oxides and carbon allotropes are desired as participants in these hybrid materials since they can provide distinctive optical, physical, magnetic, and electrochemical properties. Beyond this, synthetic polymer-based and proteinaceous or viral nanoparticulate materials are also useful in the same role since they can provide a predefined and biocompatible cargo-carrying and targeting capability. The DNA component typically provides sequence-based addressability for probes along with, more recently, unique architectural properties that directly originate from the burgeoning structural DNA field. Additionally, DNA aptamers can also provide specific recognition capabilities against many diverse non-nucleic acid targets across a range of size scales from ions to full protein and cells. In addition to appending DNA to inorganic or polymeric nanoparticles, purely DNA-based nanoparticles have recently surfaced as an excellent assembly platform and have started finding application in areas like sensing, imaging and immunotherapy. We focus on selected and representative nanoparticle-DNA materials and highlight their myriad applications using examples from the literature. Overall, it is clear that this unique functional combination of nanomaterials has far more to offer than what we have seen to date and as new capabilities for each of these materials are developed, so, too, will new applications emerge.

Theranostic multimodular potential of zinc-doped ferrite-saturated metal-binding protein-loaded novel nanocapsules in cancers

The present study successfully developed orally deliverable multimodular zinc (Zn) iron oxide (Fe3O4)-saturated bovine lactoferrin (bLf)-loaded polymeric nanocapsules (NCs), and evaluated their theranostic potential (antitumor efficacy, magnetophotothermal efficacy and imaging capability) in an in vivo human xenograft CpG-island methylator phenotype (CIMP)-1(+)/CIMP2(-)/chromosome instability-positive colonic adenocarcinoma (Caco2) and claudin-low, triple-negative (ER(-)/PR(-)/HER2(-); MDA-MB-231) breast cancer model. Mice fed orally on the Zn-Fe-bLf NC diet showed downregulation in tumor volume and complete regression in tumor volume after 45 days of feeding. In human xenograft colon cancer, vehicle-control NC diet-group (n=5) mice showed a tumor volume of 52.28±11.55 mm(3), and Zn-Fe-bLf NC diet (n=5)-treated mice had a tumor-volume of 0.10±0.073 mm(3). In the human xenograft breast cancer model, Zn-Fe-bLf NC diet (n=5)-treated mice showed a tumor volume of 0.051±0.062 mm(3) within 40 days of feeding. Live mouse imaging conducted by near-infrared fluorescence imaging of Zn-Fe-bLf NCs showed tumor site-specific localization and regression of colon and breast tumor volume. Ex vivo fluorescence-imaging analysis of the vital organs of mice exhibited sparse localization patterns of Zn-Fe-bLf NCs and also confirmed tumor-specific selective localization patterns of Zn-Fe-bLf NCs. Dual imaging using magnetic resonance imaging and computerized tomography scans revealed an unprecedented theranostic ability of the Zn-Fe-bLf NCs. These observations warrant consideration of multimodular Zn-Fe-bLf NCs for real-time cancer imaging and simultaneous cancer-targeted therapy.

Facile synthesis of a multifunctional copolymer via a concurrent RAFT-enzymatic system for theranostic applications

Through a straightforward concurrent RAFT-enzymatic multicomponent polymerization system and subsequent post-polymerization modifications, a multi-functional copolymer for theranostic application has been efficiently prepared.

Engineered mesenchymal stem cells with enhanced tropism and paracrine secretion of cytokines and growth factors to treat traumatic brain injury

Traumatic brain injury (TBI) is the leading cause of death and disability worldwide. Mesenchymal stem cells (MSCs) are promising for the treatment of various diseases and injuries. Many strategies have been applied to attract MSCs to injury site after systemic infusion. In this study, we evidenced that the CXC chemokine receptor 4 (CXCR4)-SDF1α (stromal cell-derived factor 1α) axis in engineered MSCs serves not only to attract MSC migration to TBI but also to activate Akt kinase signaling pathway in MSCs to promote paracrine secretion of cytokines and growth factors. This leads to enhanced vasculogenesis and neuroprotection at the boundary of TBI for improved blood supply, recovery of axon connectivity, and behavioral ability and results in positive feedback loop to enhance additional MSC tropism to injury. These findings indicate a new aspect of SDF1α in mediating CXCR4 engineered MSCs for brain trauma homing and recovery. This potential mechanism may be applicable to other injuries, where CXCR4-SDF1α interaction is highly associated.

Microfluidics-assisted generation of stimuli-responsive hydrogels based on alginates incorporated with thermo-responsive and amphiphilic polymers as novel biomaterials

We used a droplet-based microfluidics technique to produce monodisperse responsive alginate-block-polyetheramine copolymer microgels. The polyetheramine group (PEA), corresponding to a propylene oxide /ethylene oxide ratio (PO/EO) of 29/6 (Jeffamine(®) M2005), was condensed, via the amine link, to alginates with various mannuronic/guluronic acids ratios and using two alginate:jeffamine mass ratios. The size of the grafted-alginate microgels varied from 60 to 80 μm depending on the type of alginate used and the degree of substitution. The droplet-based microfluidics technique offered exquisite control of both the dimension and physical chemical properties of the grafted-alginate microgels. These microgels were therefore comparable to isolated grafted-alginate chains in retaining both their amphiphilic and thermo-sensitive properties. Amphiphilicity was demonstrated at the oil-water interface where grafted-alginate microgels were found to decrease interfacial tension by ∼ 50%. The thermo-sensitivity of microgels was clearly demonstrated and a 10 to 20% reduction in size between was evidenced on increasing the temperature above the lower critical solution temperature (TLCST) of Jeffamine. In addition, the reversibility of thermo-sensitivity was demonstrated by studying the oil-water affinity of microgels with temperature after Congo red labeling. Finally, droplet-based microfluidics was found to be a good and promising tool for generating responsive biobased hydrogels for drug delivery applications and potential new colloidal stabilizers for dispersed systems such as Pickering emulsions.

Multifunctional gold nanostars for molecular imaging and cancer therapy

Plasmonics-active gold nanoparticles offer excellent potential in molecular imaging and cancer therapy. Among them, gold nanostars (AuNS) exhibit cross-platform flexibility as multimodal contrast agents for macroscopic X-ray computer tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), as well as nanoprobes for photoacoustic tomography (PAT), two-photon photoluminescence (TPL), and surface-enhanced Raman spectroscopy (SERS). Their surfactant-free surface enables versatile functionalization to enhance cancer targeting, and allow triggered drug release. AuNS can also be used as an efficient platform for drug carrying, photothermal therapy, and photodynamic therapy (PDT). This review paper presents the latest progress regarding AuNS as a promising nanoplatform for cancer nanotheranostics. Future research directions with AuNS for biomedical applications will also be discussed.

Polymeric Nanovehicle Regulated Spatiotemporal Real-Time Imaging of the Differentiation Dynamics of Transplanted Neural Stem Cells after Traumatic Brain Injury

Recent advances in neural stem cell (NSC) transplantation have led to an inspiring progress in alleviating central nervous system (CNS) damages and restoring brain functions from diseases or injuries. One challenge of NSC transplantation is directed differentiation of transplanted NSCs into desired neuronal subtypes, such as neurons, to compensate the adverse impact of brain injury; another challenge lies in the lack of tools to noninvasively monitor the dynamics of NSC differentiation after transplantation in vivo. In this study, we developed a polymer nanovehicle for morphogen sustained release to overcome the drawbacks of conventional methods to realize the long-term directed NSC differentiation in vivo. Moreover, we constructed a bicistronic vector with a unique neuron specific gene tubb3 promoter to drive reporter gene expression for real-time imaging of NSC differentiation and migration. The developed uniform nanovehicle showed efficient NSC uptake and achieved a controlled release of morphogen in cytosol to consistently stimulate NSC differentiation into neurons at a sustainably effective concentration. The spatiotemporal imaging results showed a multiplexed migration, proliferation, differentiation, and apoptosis orchestra of transplanted NSCs regulated by nanovehicles in TBI mice. The imaging results also uncovered the peak time of NSC differentiation in vivo. Although we observed only a handful of NSCs ultimately migrated to the TBI area and differentiated into neurons, those neurons were functional, ameliorating the detrimental impact of TBI. The imaging findings enabled by the nanovehicle and the neuron specific bicistronic vector provide additional understanding of the in vivo behaviors of transplanted NSCs in neuronal regenerative medicine.

Self-Assembled Hybrids of Fluorescent Carbon Dots and PAMAM Dendrimers for Epirubicin Delivery and Intracellular Imaging

Advanced nanomaterials integrating imaging and therapeutic modalities on a single platform offers a new horizon in current cancer treatment strategies. Recently, carbon dots (CQDs) have been successfully employed for bioimaging of cancer cells. In the present study, luminescent CQDs with anionic terminus and cationic acetylated G5 poly(amido amine) (G5-Ac85) dendrimers were combined via noncovalent interactions to form self-assembled fluorescent hybrids. The fluorescence of CQDs in hybrids is enhanced in the vicinity of primary amine groups of dendrimers, making them suitable as cellular imaging probes. Encapsulation of chemo-drug epirubicin (EPI) in the dendrimer interiors endowed the fluorescent hybrids with therapeutic potential. The in vitro release of an entrapped EPI drug from CQDs@EPI⊂G5-Ac85 hybrids was faster in an acidic environment than under physiological conditions. Herein, multifunctional CQDs@EPI⊂G5-Ac85 hybrids serve as a dual-emission delivery system, to track the intracellular distribution and cytotoxic effects of EPI drugs. Green emission properties of CQDs were used for fluorescence microscopic imaging and cellular uptake by flow cytometry. Cell cycle analysis, field-emission scanning electron microscopy (FE-SEM), reactive oxygen species (ROS) generation, and up-regulation of apoptotic signaling genes unanimously demonstrated the apoptosis inducing ability of CQDs@EPI⊂G5-Ac85 hybrids in breast cancer (MCF-7) cells. Therefore, we have evaluated CQDs@EPI⊂G5-Ac85 hybrids as prospective candidates to achieve simultaneous imaging and drug delivery in cancer cells.