Degradation of Drug Delivery Nanocarriers and Payload Release: A Review of Physical Methods for Tracing Nanocarrier Biological Fate

Hydrogels in cardiac tissue engineering: application and challenges

Cardiovascular disease remains the leading cause of global mortality. Current stem cell therapy and heart transplant therapy have limited long-term stability in cardiac function. Cardiac tissue engineering may be one of the key methods for regenerating damaged myocardial tissue. As an ideal scaffold material, hydrogel has become a viable tissue engineering therapy for the heart. Hydrogel can not only provide mechanical support for infarcted myocardium but also serve as a carrier for various drugs, bioactive factors, and cells to increase myocardial contractility and improve the cell microenvironment in the infarcted area, thereby improving cardiac function. This paper reviews the applications of hydrogels and biomedical mechanisms in cardiac tissue engineering and discusses the challenge of clinical transformation of hydrogel in cardiac tissue engineering, providing new strategies for treating cardiovascular diseases.

Evodiamine and its nano-based approaches for enhanced cancer therapy: recent advances and challenges

Evodiamine is a bioactive alkaloid extracted from the Evodia rutaecarpa plant. It has various pharmacological effects including anti-cancer, anti-bacterial, anti-obesity, anti-neurodegenerative, anti-depressant, and cardiac protective properties. Evodiamine demonstrates potent anti-cancer activity by inhibiting the proliferation of cancer cells in vitro and in vivo. Despite the health-promoting properties of evodiamine, its clinical use is hindered by low water solubility, poor bioavailability, and toxicity. Thus, there is a need to develop alternative drug delivery systems for evodiamine to enhance its solubility, permeability, and stability, as well as to facilitate targeted, prolonged, and controlled drug release. Nanocarriers can increase the therapeutic potential of evodiamine in cancer therapy while reducing adverse side effects. To date, numerous attempts have been made through the development of smart nanocarriers to overcome the drawbacks of evodiamine. This review focuses on the pharmacological applications, anti-cancer mechanisms, and limitations of evodiamine. Various nanocarriers, including lipid-based nanoparticles, polymeric nanoparticles, cyclodextrins, and so forth, have been discussed extensively for evodiamine delivery. Nano-drug delivery systems could increase the solubility, bioavailability, stability, and therapeutic efficacy of evodiamine. This review aims to present a comprehensive and critical evaluation of several nano-formulations of evodiamine for cancer therapy. © 2024 Society of Chemical Industry.

Mechanisms of extracellular vesicle uptake and implications for the design of cancer therapeutics

The translation of pre-clinical anti-cancer therapies to regulatory approval has been promising, but slower than hoped. While innovative and effective treatments continue to achieve or seek approval, setbacks are often attributed to a lack of efficacy, failure to achieve clinical endpoints, and dose-limiting toxicities. Successful efforts have been characterized by the development of therapeutics designed to specifically deliver optimal and effective dosing to tumour cells while minimizing off-target toxicity. Much effort has been devoted to the rational design and application of synthetic nanoparticles to serve as targeted therapeutic delivery vehicles. Several challenges to the successful application of this modality as delivery vehicles include the induction of a protracted immune response that results in their rapid systemic clearance, manufacturing cost, lack of stability, and their biocompatibility. Extracellular vesicles (EVs) are a heterogeneous class of endogenous biologically produced lipid bilayer nanoparticles that mediate intercellular communication by carrying bioactive macromolecules capable of modifying cellular phenotypes to local and distant cells. By genetic, chemical, or metabolic methods, extracellular vesicles (EVs) can be engineered to display targeting moieties on their surface while transporting specific cargo to modulate pathological processes following uptake by target cell populations. This review will survey the types of EVs, their composition and cargoes, strategies employed to increase their targeting, uptake, and cargo release, and their potential as targeted anti-cancer therapeutic delivery vehicles.

Application of Box-Behnken design in the optimization and development of albendazole-loaded zein nanoparticles as a drug repurposing approach for colorectal cancer management

Colorectal cancer (CRC) is the second cancer worldwide representing a major global health challenge. Numerous effective anticancer drugs have been developed in the last decade, yet the problem remains due to their low therapeutic index and nonspecificity. A new anticancer therapeutic paradigm is based on repurposing and nanoformulating drugs. Albendazole (ALB), a popular anthelmintic agent, was recently repurposed against CRC cells. In this study zein, an amphiphilic protein, was used to formulate nanoparticles (NPs) loaded with ALB. Box-Behnken design was selected to optimize the loaded NPs, the concentrations of polyvinyl alcohol, acetic acid, and the weight of zein were the independent variables. The dependent variables were the particle size, polydispersity index, and zeta potential. The optimized formula displayed a size of 84.3 ± 0.41 nm, PDI 0.13 ± 0.012, and a zeta potential of 42.5 ± 2.35 mV. ALB was successfully encapsulated into zein NPs and the release study revealed a desirable pH-responsive drug release behavior, that was negligible release during the first 2 h at pH 1.2 and progressive in the simulated colon environment reaching 71.1 ± 0.34 % at 6 h and 92.4 ± 1.11 % at 24 h. The anticancer effect of the loaded NPs on the human HCT116 cells showed favorable effects at 1 μM concentration with a significant decrease in the IC50 at days 2 and 3 upon loading albendazole into zein NPs. Zein nanoparticles proved to be prospective nanocarriers that could be used for the delivery of repurposed drugs in CRC treatment.

Synthesis, evaluation and modification of heterofunctional polyester dendrimers with internally queued bromide groups

Heterofunctional polyester dendrimers up to the third generation, containing 21 internally queued bromine atoms, have been successfully synthesized for the first time using a divergent growth approach. Direct azidation reactions enabled the conversion of the bromide groups to clickable azide pendant functionalities. Therapeutic and chemical moeities could then be coupled to the internal azide or bromide functionalities and external hydroxyl groups of the heterofunctional dendrimers through CuAAC, thiol-bromo click and esterification reactions, expanding their potential for biomedical applications.

pH-tailored delivery of a multitarget anticancer benzimidazole derivative using a PEGylated β-cyclodextrin-curcumin functionalized nanocomplex

In this study, we aimed to enhance the bioavailability of a benzimidazole derivative with potent anticancer potential through a nano-based approach. Benzimidazole-loaded polyethylene glycol-β-cyclodextrin-functionalized curcumin nanocomplex (BMPE-Cur) was prepared and characterized for its physicochemical properties and drug release profiles under different pH conditions. In addition, the biological activities of the nanocomplex including antioxidant potentials and pro-apoptogenic properties, against HepG2, PC3, and the chemo-resistant MCF-7-ADR cell lines relative to the normal Wi-38 cell line were in vitro assessed and compared with those of the free benzimidazole compound. In addition to FTIR, XRD, and NMR spectral studies, a polymeric nanocomplex with an average particle size of 467.7 nm and high stability was successfully developed, as indicated by the negative zeta potential (-28.24 mV). The nanocomplex also showed prolonged pH-sensitive sustained drug release under conditions that replicated the tumor's extra/intracellular pH. The formulated nanocomplex also demonstrated potent radical scavenging capacity owing to the inclusion of curcumin, a known radical quencher. In addition, compared with the free compound, BMPE-Cur induced DNA fragmentation-driven cell cycle arrest in HepG2, PC3, and MCF-7-ADR cells at the G1/S, G1 & S phases; respectively, with remarkable selectivity. In conclusion, the newly formulated BMPE-Cur nanocomplex represents an attractive multitarget anticancer candidate.

Fillable Magnetic Microrobots for Drug Delivery to Cardiac Tissues In Vitro

Many cardiac diseases, such as arrhythmia or cardiogenic shock, cause irregular beating patterns that must be regulated to prevent disease progression toward heart failure. Treatments can include invasive surgery or high systemic drug dosages, which lack precision, localization, and control. Drug delivery systems (DDSs) that can deliver cargo to the cardiac injury site could address these unmet clinical challenges. Here, a microrobotic DDS that can be mobilized to specific sites via magnetic control is presented. This DDS incorporates an internal chamber that can protect drug cargo. Furthermore, the DDS contains a tunable thermosensitive sealing layer that gradually degrades upon exposure to body temperature, enabling prolonged drug release. Once loaded with the small molecule drug norepinephrine, this microrobotic DDS modulated beating frequency in induced pluripotent stem-cell derived cardiomyocytes (iPSC-CMs) in a dose-dependent manner, thus simulating drug delivery to cardiac cells in vitro. The DDS also navigates several maze-like structures seeded with cardiomyocytes to demonstrate precise locomotion under a rotating low-intensity magnetic field and on-site drug delivery. This work demonstrates the utility of a magnetically actuating DDS for precise, localized, and controlled drug delivery which is of interest for a myriad of future opportunities such as in treating cardiac diseases.

A second generation of senotherapies: the development of targeted senolytics, senoblockers and senoreversers for healthy ageing

Cellular senescence, a form of terminal cell cycle arrest, is as a key driver of organismal ageing and an important factor in age-related diseases. Insights into the senescent phenotype have led to the development of novel therapeutic strategies, collectively known as senotherapies, that aim to ameliorate the detrimental effects of senescent cell accumulation in tissues. The senotherapeutic field has rapidly evolved over the past decade, with clinical translation of the first drugs discovered currently underway. What began as the straightforward removal of senescent cells using repurposed compounds, which were given the name of senolytics, has grown into an expanding field that uses different state of the art approaches to achieve the goal of preventing the build-up of senescent cells in the body. Here, we summarize the emergence of a new generation of senotherapies, based on improving the efficacy and safety of the original senolytics by making them targeted, but also branching out into drugs that prevent senescence (senoblockers) or revert it (senoreversers).The use of nanotechnology, specific antibodies, cell-based approaches and restored immunosurveillance is likely to revolutionize the field of senotherapies in the near future, hopefully allowing it to realize its full clinical potential.

Carbon nanomaterials as carriers for the anti-cancer drug doxorubicin: a review on theoretical and experimental studies

The incidence of cancer is increasing worldwide in a life-threatening manner. In such a scenario, the development of anti-cancer drugs with minimal side effects and effective drug delivery systems is of paramount importance. Doxorubicin (DOX) is one of the powerful anti-cancer drugs from the chemical family anthracycline, which is used to treat a wide variety of cancers, including breast, prostate, ovarian, and hematological malignancies. However, DOX has been associated with many side effects, including lethal cardiotoxicity, baldness, gastrointestinal disturbances and cognitive function impairment. Even though DOX is administered in liposomal formulations to reduce its toxicity and enhance its therapeutic profile, the liposomal formulations themselves have certain therapeutic profile limitations such as "palmar-plantar erythrodysesthesia (PPE)", which shows severe swelling and redness in the skin, thus restricting the dosage and reducing patient compliance. In contemporary chemotherapy research, there is a great interest in the utilization of nanomaterials for precise and targeted drug delivery applications, especially using carbon-based nanomaterials. This review provides a comprehensive overview of both experimental and theoretical scientific works, exploring diverse forms of carbon-based materials such as graphene, graphene oxide, and carbon nanotubes that function as carriers for DOX. In addition, the review consolidates information on the fate of the carriers after the delivery of the payload at the site of action through different imaging techniques and the various pathways through which the body eliminates these nanomaterials. In conclusion, the review presents a detailed overview of the toxicities associated with these carriers within the human body, contributing to the development of enhanced drug delivery systems.

Exploring Simple Particle-Based Signal Amplification Strategies in a Heterogeneous Sandwich Immunoassay with Optical Detection

Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current "gold standard" enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidin-functionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C-reactive protein (CRP), the analyte sensitivity achievable with optimized PSP systems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept.

Raman Flow Cytometry and Its Biomedical Applications

Raman flow cytometry (RFC) uniquely integrates the "label-free" capability of Raman spectroscopy with the "high-throughput" attribute of traditional flow cytometry (FCM), offering exceptional performance in cell characterization and sorting. Unlike conventional FCM, RFC stands out for its elimination of the dependency on fluorescent labels, thereby reducing interference with the natural state of cells. Furthermore, it significantly enhances the detection information, providing a more comprehensive chemical fingerprint of cells. This review thoroughly discusses the fundamental principles and technological advantages of RFC and elaborates on its various applications in the biomedical field, from identifying and characterizing cancer cells for in vivo cancer detection and surveillance to sorting stem cells, paving the way for cell therapy, and identifying metabolic products of microbial cells, enabling the differentiation of microbial subgroups. Moreover, we delve into the current challenges and future directions regarding the improvement in sensitivity and throughput. This holds significant implications for the field of cell analysis, especially for the advancement of metabolomics.

Organic and Biogenic Nanocarriers as Bio-Friendly Systems for Bioactive Compounds' Delivery: State-of-the Art and Challenges

"Green" strategies to build up novel organic nanocarriers with bioperformance are modern trends in nanotechnology. In this way, the valorization of bio-wastes and the use of living systems to develop multifunctional organic and biogenic nanocarriers (OBNs) have revolutionized the nanotechnological and biomedical fields. This paper is a comprehensive review related to OBNs for bioactives' delivery, providing an overview of the reports on the past two decades. In the first part, several classes of bioactive compounds and their therapeutic role are briefly presented. A broad section is dedicated to the main categories of organic and biogenic nanocarriers. The major challenges regarding the eco-design and the fate of OBNs are suggested to overcome some toxicity-related drawbacks. Future directions and opportunities, and finding "green" solutions for solving the problems related to nanocarriers, are outlined in the final of this paper. We believe that through this review, we will capture the attention of the readers and will open new perspectives for new solutions/ideas for the discovery of more efficient and "green" ways in developing novel bioperformant nanocarriers for transporting bioactive agents.

Biohybrid Nanoparticle-Based In Situ Monitoring of In Vivo Drug Delivery

Nanomaterials have gained huge attention worldwide owing to their unique physicochemical characteristics which enable their applications in the field of biomedicine and drug delivery systems. Although nanodrug delivery systems (NDDSs) have better target specificity and bioavailability than traditional drug delivery systems, their behavior and clearance mechanisms in living subjects remain unclear. In this regard, the importance of bioimaging methods has come to the forefront for investigating the biodistribution of nanocarriers and discovering drug release mechanisms in vivo. In this review, we introduce several examples of biohybrid nanoparticles and their clinical applications, focusing on their advantages and limitations. The various bioimaging methods for monitoring the fate of nanodrugs in biological systems and the future perspectives of NDDSs have also been discussed.

Fucoidan-loaded electrospun Polyvinyl-alcohol/Chitosan nanofibers with enhanced antibacterial activity for skin tissue engineering

The polymeric nanofiber may interact and control certain regeneration processes at the molecular level to repair damaged tissues. This research focuses on the development of characterization and antibacterial capabilities of polyvinyl alcohol (PVA)/chitosan (CS) nanofibres containing fucoidan (FUC) for tissue engineering as a skin tissue substitute. A control group consisting of 13% PVA/(0.1)% CS nanofiber was prepared. To confer antibacterial properties to the nanofiber, 10, 20, and 30 mg of FUC were incorporated into this control group. The scanning electron microscope (SEM) proved the homogeneous and beadless structures of the nanofibers. The antibacterial activity of the 13% PVA/(0.1)% CS/(10, 20, 30) FUC was tested against the S.aureus and E.coli and the results showed that with FUC addition, the antibacterial activities of the nanofibers increased. The biocompatibility test was performed with a fibroblast cell line for 1, 3, and 7 days of incubation and the results demonstrated that FUC addition enhanced the bioactivity of the 13% PVA/(0.1)% CS nanofibers. In addition, the biocompatibility results showed that 13% PVA/(0.1)% CS/10 FUC had the highest viability value for all incubation periods compared to the others. In addition, the tensile test results showed that; the maximum tensile strength value was observed for 13% PVA/(0.1)% CS/10 FUC nanofibers.

Harnessing biomaterial architecture to drive anticancer innate immunity

Immunomodulation is a powerful therapeutic approach that harnesses the body's own immune system and reprograms it to treat diseases, such as cancer. Innate immunity is key in mobilizing the rest of the immune system to respond to disease and is thus an attractive target for immunomodulation. Biomaterials have widely been employed as vehicles to deliver immunomodulatory therapeutic cargo to immune cells and raise robust antitumor immunity. However, it is key to consider the design of biomaterial chemical and physical structure, as it has direct impacts on innate immune activation and antigen presentation to stimulate downstream adaptive immunity. Herein, we highlight the widespread importance of structure-driven biomaterial design for the delivery of immunomodulatory cargo to innate immune cells. The incorporation of precise structural elements can be harnessed to improve delivery kinetics, uptake, and the targeting of biomaterials into innate immune cells, and enhance immune activation against cancer through temporal and spatial processing of cargo to overcome the immunosuppressive tumor microenvironment. Structural design of immunomodulatory biomaterials will profoundly improve the efficacy of current cancer immunotherapies by maximizing the impact of the innate immune system and thus has far-reaching translational potential against other diseases.

Advancement in Biopolymer Assisted Cancer Theranostics

Applications of nanotechnology have increased the importance of research and nanocarriers, which have revolutionized the method of drug delivery to treat several diseases, including cancer, in the past few years. Cancer, one of the world's fatal diseases, has drawn scientists' attention for its multidrug resistance to various chemotherapeutic drugs. To minimize the side effects of chemotherapeutic agents on healthy cells and to develop technological advancement in drug delivery systems, scientists have developed an alternative approach to delivering chemotherapeutic drugs at the targeted site by integrating it inside the nanocarriers like synthetic polymers, nanotubes, micelles, dendrimers, magnetic nanoparticles, quantum dots (QDs), lipid nanoparticles, nano-biopolymeric substances, etc., which has shown promising results in both preclinical and clinical trials of cancer management. Besides that, nanocarriers, especially biopolymeric nanoparticles, have received much attention from researchers due to their cost-effectiveness, biodegradability, treatment efficacy, and ability to target drug delivery by crossing the blood-brain barrier. This review emphasizes the fabrication processes, the therapeutic and theragnostic applications, and the importance of different biopolymeric nanocarriers in targeting cancer both in vitro and in vivo, which conclude with the challenges and opportunities of future exploration using biopolymeric nanocarriers in onco-therapy with improved availability and reduced toxicity.

Rational nanoparticle design: Optimization using insights from experiments and mathematical models

Polymeric nanoparticles are highly tunable drug delivery systems that show promise in targeting therapeutics to specific sites within the body. Rational nanoparticle design can make use of mathematical models to organize and extend experimental data, allowing for optimization of nanoparticles for particular drug delivery applications. While rational nanoparticle design is attractive from the standpoint of improving therapy and reducing unnecessary experiments, it has yet to be fully realized. The difficulty lies in the complexity of nanoparticle structure and behavior, which is added to the complexity of the physiological mechanisms involved in nanoparticle distribution throughout the body. In this review, we discuss the most important aspects of rational design of polymeric nanoparticles. Ultimately, we conclude that many experimental datasets are required to fully model polymeric nanoparticle behavior at multiple scales. Further, we suggest ways to consider the limitations and uncertainty of experimental data in creating nanoparticle design optimization schema, which we call quantitative nanoparticle design frameworks.

Cellular uptake and retention studies of silica nanoparticles utilizing senescent fibroblasts

Understanding the interplay between nanoparticles (NPs) and cells is essential to designing more efficient nanomedicines. Previous research has shown the role of the cell cycle having impact on the efficiency of cellular uptake and accumulation of NPs. However, there is a limited investigation into the biological fate of NPs in cells that are permanently withdrawn from the cell cycle. Here we utilize senescent WI-38 fibroblasts, which do not divide and provide a definitive model for tracking the biological fate of silica nanoparticles (SiNPs) independent of cell cycle. We use several methods to measure the cellular uptake kinetics and intracellular retention of SiNPs, including confocal laser scanning microscopy (CLSM), flow cytometry, and transmission electron microscopy (TEM). We demonstrate that SiNPs readily enter into senescent cells. Once internalized, SiNPs do not exit and accumulate in the cytoplasm for long term. Our study provides a basis for future development of NP-based tools that can detect and target senescent cells for therapy.

Nanocapsules: An Emerging Drug Delivery System

BACKGROUND

Controlled drug release and site-specific delivery of drugs make nanocapsules the most approbative drug delivery system for various kinds of drugs, bioactive, protein, and peptide compounds. Nanocapsules (NCs) are spherical shape microscopic shells consisting of a core (solid or liquid) in which the drug is positioned in a cavity enclosed by a distinctive polymeric membrane.

OBJECTIVES

The main objective of the present patent study is to elaborate on various formulation techniques and methods of nanocapsules (NCs). The review also spotlights various biomedical applications as well as on the patents of NCs to date.

METHODS

The review was extracted from the searches performed using various search engines such as PubMed, Google Patents, Medline, Google Scholars, etc. In order to emphasize the importance of NCs, some published patents of NCs have also been reported in the review.

RESULTS

NCs are tiny magical shells having incredible reproducibility. Various techniques can be used to formulate NCs. The pharmaceutical performance of the formulated NCs can be judged by evaluating their shape, size, entrapment efficiency, loading capacity, etc., using different analytical techniques. Their main applications are found in the field of agrochemicals, genetic manipulation, cosmetics, hygiene items, strategic distribution of drugs to tumors, nanocapsule bandages to combat infection, and radiotherapy.

CONCLUSION

In the present review, our team made a deliberate effort to summarize the recent advances in the field of NCs and focus on new patents related to the implementation of NCs delivery systems in the area of some life-threatening disorders like diabetes, cancer, and cardiovascular diseases.

Recent Progress in the Hesperetin Delivery Regimes: Significance of Pleiotropic Actions and Synergistic Anticancer Efficacy

BACKGROUND

In the plant kingdom, flavonoids are widely distributed with multifunctional immunomodulatory actions. Hesperetin (HST) remains one of the well-studied compounds in this domain, initially perceived in citrus plants as an aglycone derivative of hesperidin (HDN).

OBSERVATIONS

Natural origin, low in vivo toxicity, and pleiotropic functional essence are the foremost fascinations for HST use as an anticancer drug. However, low aqueous solubility accompanied with a prompt degradation by intestinal and hepatocellular enzymes impairs HST physiological absorption.

MOTIVATION

Remedies attempted herein comprise the synthesis of derivatives and nanocarrier (NC)-mediated delivery. As the derivative synthesis aggravates the structural complexity, NC-driven HST delivery has emerged as a sustainable approach for its sustained release. Recent interest in HST has been due to its significant anticancer potential, characterized via inhibited cell division (proliferation), new blood vessel formation (angiogenesis), forceful occupation of neighboring cell's space (invasion), migration to erstwhile physiological locations (metastasis) and apoptotic induction. The sensitization of chemotherapeutic drugs (CDs) by HST is driven via stoichiometrically regulated synergistic actions. Purpose and Conclusion: This article sheds light on HST structure-function correlation and pleiotropic anticancer mechanisms, in unaided and NC-administered delivery in singular and with CDs synergy. The discussion could streamline the HST usefulness and long-term anticancer efficacy.

Metal-Organic Frameworks as Intelligent Drug Nanocarriers for Cancer Therapy

Metal-organic frameworks (MOFs) are crystalline porous materials with periodic network structures formed by self-assembly of metal ions and organic ligands. Attributed to their tunable composition and pore size, ultrahigh surface area (1000-7000 m2/g) and pore volume (1.04-4.40 cm3/g), easy surface modification, appropriate physiological stability, etc., MOFs have been widely used in biomedical applications in the last two decades, especially for the delivery of bioactive agents. In the initial stage, MOFs were widely used to load small molecule drugs with ultra-high doses. Whereafter, more recent work has focused on the load of biomacromolecules, such as nucleic acids and proteins. Over the past years, we have devoted extensive effort to investigate the function of MOF materials for bioactive agent delivery. MOFs can be used not only as an intelligent nanocarrier to deliver or protect bioactive agents but also as an activator for their release or activation in response to the different microenvironments. Altogether, this review details the current progress of MOF materials for bioactive agent delivery and looks into their future development.

Shining Light on Polymeric Drug Nanocarriers with Fluorescence Correlation Spectroscopy

The use of nanoparticles as carriers is an extremely promising way for administration of therapeutic agents, such as drug molecules, proteins and nucleic acids. Such nanocarriers (NCs) can increase the solubility of hydrophobic compounds, protect their cargo from the environment, and if properly functionalized, deliver it to specific target cells and tissues. Polymer-based NCs are especially promising, because they offer high degree of versatility and tunability. However, in order to get a full advantage of this therapeutic approach and develop efficient delivery systems, a careful characterization of the NCs is needed. This Feature Article highlights the fluorescence correlation spectroscopy (FCS) technique as a powerful and versatile tool for NCs characterization at all stages of the drug delivery process. In particular, FCS can monitor and quantify the size of the NCs and the drug loading efficiency after preparation, the NCs stability and possible interactions with, e.g., plasma proteins in the blood stream and the kinetic of drug release in the cytoplasm of the target cells. This article is protected by copyright. All rights reserved.

Light-Decomposable Polymeric Micelles with Hypoxia-Enhanced Phototherapeutic Efficacy for Combating Metastatic Breast Cancer

Oxygen dependence and anabatic hypoxia are the major factors responsible for the poor outcome of photodynamic therapy (PDT) against cancer. Combining of PDT and hypoxia-activatable bioreductive therapy has achieved remarkably improved antitumor efficacy compared to single PDT modality. However, controllable release and activation of prodrug and safety profiles of nanocarrier are still challenging in the combined PDT/hypoxia-triggered bioreductive therapy. Herein, we developed a near infrared (NIR) light-decomposable nanomicelle, consisting of PEGylated cypate (pCy) and mPEG-polylactic acid (mPEG_2k-PLA_2k) for controllable delivery of hypoxia-activated bioreductive prodrug (tirapazamine, TPZ) (designated TPZ@pCy), for combating metastatic breast cancer via hypoxia-enhanced phototherapies. TPZ@pCy was prepared by facile nanoprecipitation method, with good colloidal stability, excellent photodynamic and photothermal potency, favorable light-decomposability and subsequent release and activation of TPZ under irradiation. In vitro experiments demonstrated that TPZ@pCy could be quickly internalized by breast cancer cells, leading to remarkable synergistic tumor cell-killing potential. Additionally, metastatic breast tumor-xenografted mice with systematic administration of TPZ@pCy showed notable tumor accumulation, promoting tumor ablation and lung metastasis inhibition with negligible toxicity upon NIR light illumination. Collectively, our study demonstrates that this versatile light-decomposable polymeric micelle with simultaneous delivery of photosensitizer and bioreductive agent could inhibit tumor growth as well as lung metastasis, representing a promising strategy for potent hypoxia-enhanced phototherapies for combating metastatic breast cancer.

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.

Design of a Platelet-Mediated Delivery System for Drug-Incorporated Nanospheres to Enhance Anti-Tumor Therapeutic Effect

The objective of this study is to construct a platelet-mediated delivery system for drug-incorporated nanospheres. Nanospheres of poly(lactic-co-glycolic acid) (PLGA-NS) with different sizes and surface properties were prepared by changing the preparation parameters, such as the type of polymer surfactant, the concentration of polymer surfactant and PLGA, and the stirring rate. When incubated with platelets, PLGA-NS prepared with poly(vinyl alcohol) suppressed the platelet activation. Scanning electron microscopic and flow cytometry examinations revealed that platelets associated with PLGA-NS (platelet hybrids, PH) had a similar appearance and biological properties to those of the original platelets. In addition, the PH with PLGA-NS specifically adhered onto the substrate pre-coated with fibrin to a significantly great extent compared with PLGA-NS alone. When applied in an in vitro model of tumor tissue which was composed of an upper chamber pre-coated with fibrin and a lower chamber culturing tumor cells, the PH with PLGA-NS incorporating an anti-tumor drug were delivered to the tumor cells through the specific adhesion onto the upper chamber and, consequently, drug release from the upper chamber took place, resulting in the growth suppression of tumor cells. It is concluded that the drug delivery system based on PH is promising for tumor treatment.