Alizarin Complexone Functionalized Mesoporous Silica Nanoparticles: A Smart System Integrating Glucose-Responsive Double-Drugs Release and Real-Time Monitoring Capabilities

Nanomaterials for diabetes: diagnosis, detection and delivery

537 million people worldwide suffer from diabetes mellitus, a problem of glucose management that is related to a number of major health risks, including cardiovascular diseases. There is a need for new, efficient formulations of diabetic medications to address this condition and its related consequences because existing treatments have a number of drawbacks and limits. This encouraged the development of treatment plans to get around some of these restrictions, like low therapeutic drug bioavailability or patients' disobedience to existing therapies. Approaches based on nanotechnology have a lot of promise to enhance the treatment of diabetic patients. In order to manage blood glucose, this review article highlights recent developments and explores the potential applications of different materials (polymeric, ceramic, dendrimers, etc.) as nanocarriers for the delivery of insulin and other antidiabetic medications. Using an injectable and acid-degradable polymeric network produced by the electrostatic interaction of oppositely charged dextran nanoparticles loaded with insulin and glucose-specific enzymes, we reviewed a glucose-mediated release approach for the self-regulated delivery of insulin, in which, after a degradable nano-network was subcutaneously injected into type 1 diabetic mice,in vivoexperiments confirmed that these formulations improved glucose management. In addition, a discussion of silica-based nanocarriers, their potential for treating diabetes and controlling blood glucose levels, and an explanation of the role of dendrimers in diabetes treatment have been covered. This is done by utilizing the properties of silica nanoparticles, such as their tuneable particle and pore size, surface chemistry, and biocompatibility. The article summarized the significance of nanomaterials and their uses in the diagnosis and treatment of diabetes overall, illuminating the field's potential and outlining its prospects for the future.

Potential Applications and Additive Manufacturing Technology-Based Considerations of Mesoporous Silica: A Review

Nanoporous materials are categorized as microporous (pore sizes 0.2-2 nm), mesoporous (pore sizes 2-50 nm), and macroporous (pore sizes 50-1000 nm). Mesoporous silica (MS) has gained a significant interest due to its notable characteristics, including organized pore networks, specific surface areas, and the ability to be integrated in a variety of morphologies. Recently, MS has been widely accepted by range of manufacturer and as drug carrier. Moreover, silica nanoparticles containing mesopores, also known as mesoporous silica nanoparticles (MSNs), have attracted widespread attention in additive manufacturing (AM). AM commonly known as three-dimensional printing is the formalized rapid prototyping (RP) technology. AM techniques, in comparison to conventional methods, aid in reducing the necessity for tooling and allow versatility in product and design customization. There are generally several types of AM processes reported including VAT polymerization (VP), powder bed fusion (PBF), sheet lamination (SL), material extrusion (ME), binder jetting (BJ), direct energy deposition (DED), and material jetting (MJ). Furthermore, AM techniques are utilized in fabrication of various classified fields such as architectural modeling, fuel cell manufacturing, lightweight machines, medical, and fabrication of drug delivery systems. The review concisely elaborates on applications of mesoporous silica as versatile material in fabrication of various AM-based pharmaceutical products with an elaboration on various AM techniques to reduce the knowledge gap.

Recent Advancements on Self-Immolative System Based on Dynamic Covalent Bonds for Delivering Heterogeneous Payloads

The precisely spatial-temporal delivery of heterogeneous payloads from a single system with the same pulse is in great demand in realizing versatile and synergistic functions. Very few molecular architectures can satisfy the strict requirements of dual-release translated from single triggers, while the self-immolative systems based on dynamic covalent bonds represent the "state-of-art" of ultimate solution strategy. Embedding heterogeneous payloads symmetrically onto the self-immolative backbone with dynamic covalent bonds as the trigger, can respond to the quasi-bio-orthogonal hallmarks which are higher at the disease's microenvironment to simultaneously yield the heterogeneous payloads (drug A/drug B or drug/reporter). In this review, the modular design principles are concentrated to illustrate the rules in tailoring useful structures, then the rational applications are enumerated on the aspects of drug codelivery and visualized drug-delivery. This review, hopefully, can give the general readers a comprehensive understanding of the self-immolative systems based on dynamic covalent bonds for delivering heterogeneous payloads.

An ultrasensitive split-type electrochemical immunosensor based on controlled-release strategy for detection of CA19-9

In this study, a novel split-type electrochemical immunosensor based on controlled release strategy was proposed for sensitive analysis and detection of tumor marker carbohydrate antigen 199 (CA19-9). Specifically, glucose (Glu) was encapsulated in carrier mesoporous silica (MSN) with encapsulation technology, and surface functionalized Zinc sulfide (ZnS) caps were used as "gatekeepers". The complex is formed by encapsulating Glu within MSN with ZnS (ZnS@MSN-Glu) as a signal amplifier labeled on the signal antibody (Ab₂). And the Ab₂ can detect the presence of antibodies. To reduce the interference of biological analysis, the immune recognition process of ZnS@MSN-Glu-Ab₂ bioconjugate and antigen was carried out in 96-well microplate, which did not interfere with the electrochemical analysis process. Therefore, the low sensitivity detection caused by biofouling of nanomaterials and immunoreaction on the testing platform is eliminated. Subsequently, the opening and timed release of mesopores were controlled by external stimuli, the disulfide bond cleavage by dithiothreitol (DTT), and glucose was effectively released. Then nickel cobalt layered double hydroxide (NiCo-LDH) were directly hydrothermally grown on carbon cloth (CC) electrodeposited with copper selenide (CuSe) nanosheets to construct three-dimensional (3D) cactus-like NiCo-LDH/CuSe/CC sensing platform. It can realize the catalytic oxidation of released glucose, triggering glucose-mediated signal amplification. The synergistic effect of the 3D cactus structure and active nanomaterials promotes electron conduction. Taking the detection of carbohydrate antigen CA19-9 as an example, the immunosensor shows a wide linear concentration range (0.001-100 U/mL) with the limit of detection of 0.0005 U/mL, realizing highly sensitive detection of CA19-9. This biosensing technique has considerable advantages and provides an innovative approach for trace detection of other biomarkers.

Supplementation of Polymeric Reservoirs with Redox-Responsive Metallic Nanoparticles as a New Concept for the Smart Delivery of Insulin in Diabetes

Type 1 diabetes is caused by the inability of the pancreatic beta cells to produce sufficient amounts of insulin, an anabolic hormone promoting the absorption of the blood glucose by various cells in the body, primarily hepatocytes and skeletal muscle cells. This form of impaired metabolism has been traditionally treated with subcutaneous insulin injections. However, because one such method of administration does not directly correspond to the glucose concentrations in the blood and may fail to reduce hyperglycemia or cause hypoglycemia, the delivery of insulin in a glucose-dependent manner has been researched intensely in the present and past. This study tested the novel idea that the supplementation of polymeric reservoirs containing insulin with metallic nanoparticle precursors responsive to the redox effect of glucose could be used to create triggers for the release of insulin in direct response to the concentration of glucose in the tissue. For that purpose, manganese oxide nanoparticles were dispersed inside a poly(ε-caprolactone) matrix loaded with an insulin proxy and the resulting composite was exposed to different concentrations of glucose. The release of the insulin proxy occurred in direct proportion to the concentration of glucose in the medium. Mechanistically, as per the central hypothesis of the study, glucose reduced the manganese cations contained within the metal oxide phase, forming finer and more dissipative zero-valent metallic nanoparticles, thus disrupting the polymeric network, opening up pores in the matrix and facilitating the release of the captured drug. The choice of manganese for this study over other metals was justified by its use as a supplement for protection against diabetes. Numerical analysis of the release mechanism revealed an increasingly nonlinear and anomalous release accompanied by a higher diffusion rate at the expense of chain rigidity as the glucose concentration increased. Future studies should focus on rendering the glucose-controlled release (i) feasible within the physiological pH range and (ii) sensitive to physiologically relevant glucose concentrations. These technical improvements of the fundamental new concept proven here may bring it closer to a real-life application for the mitigation of symptoms of hyperglycemia in patients with diabetes.

Silica-Based Nanomaterials for Diabetes Mellitus Treatment

Diabetes mellitus, a chronic metabolic disease with an alarming global prevalence, is associated with several serious health threats, including cardiovascular diseases. Current diabetes treatments have several limitations and disadvantages, creating the need for new effective formulations to combat this disease and its associated complications. This motivated the development of therapeutic strategies to overcome some of these limitations, such as low therapeutic drug bioavailability or poor compliance of patients with current therapeutic methodologies. Taking advantage of silica nanoparticle characteristics such as tuneable particle and pore size, surface chemistry and biocompatibility, silica-based nanocarriers have been developed with the potential to treat diabetes and regulate blood glucose concentration. This review discusses the main topics in the field, such as oral administration of insulin, glucose-responsive devices and innovative administration routes.

Novel Drug and Gene Delivery System and Imaging Agent Based on Marine Diatom Biosilica Nanoparticles

Mesoporous silica nanoparticles (MSNs) have great potential for applications as a drug delivery system (DDS) due to their unique properties such as large pore size, high surface area, biocompatibility, biodegradability, and stable aqueous dispersion. The MSN-mediated DDS can carry chemotherapeutic agents, optical sensors, photothermal agents, short interfering RNA (siRNA), and gene therapeutic agents. The MSN-assisted imaging techniques are applicable in cancer diagnosis. However, their synthesis via a chemical route requires toxic chemicals and is challenging, time-consuming, and energy-intensive, making the process expensive and non-viable. Fortunately, nature has provided a viable alternative material in the form of biosilica from marine resources. In this review, the applications of biosilica nanoparticles synthesized from marine diatoms in the field of drug delivery, biosensing, imaging agents, and regenerative medicine, are highlighted. Insights into the use of biosilica in the field of DDSs are elaborated, with a focus on different strategies to improve the physico-chemical properties with regards to drug loading and release efficiency, targeted delivery, and site-specific binding capacity by surface functionalization. The limitations, as well as the future scope to develop them as potential drug delivery vehicles and imaging agents, in the overall therapeutic management, are discussed.

Insight into the Progress on Natural Dyes: Sources, Structural Features, Health Effects, Challenges, and Potential

(1) Background: Dyes play an important role in food, medicine, textile, and other industries, which make human life more colorful. With the increasing demand for food safety, the development of natural dyes becomes more and more attractive. (2) Methods: The literature was searched using the electronic databases PubMed, Web of Science, and SciFinder and this scoping review was carried out following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). (3) Results: 248 articles were included in this review. This review summarizes the research progress on natural dyes in the last ten years. According to structural features, natural dyes mainly include carotenoids, polyphenols, porphyrins, and alkaloids, and some of the newest dyes are summarized. Some pharmacological activities of carotenoids, anthocyanin, curcumin, and betalains in the last 10 years are summarized, and the biological effects of dyes regarding illumination conditions. The disadvantages of natural dyes, including sources, cost, stability, and poor bioavailability, limit their application. Here, some feasible strategies (potential resources, biotechnology, new extraction and separation strategies, strategies for improving stability) are described, which will contribute to the development and utilization of natural dyes. (4) Conclusion: Natural dyes show health benefits and potential in food additives. However, it is necessary for natural dyes to pass toxicity tests and quality tests and receive many regulatory approvals before their final entry into the market as food colorants or as drugs.

Stimuli-responsive mesoporous silica nanoparticles: A custom-tailored next generation approach in cargo delivery

The pre-mature release of therapeutic cargos in the bloodstream or off-target sites is a major hurdle in drug delivery. However, stimuli-specific drug release responses are capable of providing greater control over the cargo release. Herein, various types of nanocarriers have been employed for such applications. Among various types of nanoparticles, mesoporous silica nanoparticles (MSNPs) have several attractive characteristics, such as high loading capacity, biocompatibility, small size, porous structure, high surface area, tunable pore size and ease of functionalization of the external and internal surfaces, which facilitates the entrapment and development of stimuli-dependent release of drugs. MSNPs could be modified with such stimuli-responsive entities like nucleic acid, peptides, polymers, organic molecules, etc., to prevent pre-mature cargo release, improving the therapeutic outcome. This controlled drug release system could be modulated to function upon extracellular or intracellular specific stimuli, including pH, enzyme, glucose, glutathione, light, temperature, etc., and thus provide minimal side effects at non-target sites. This system has great potential applications for the targeted delivery of therapeutics to treat clinically challenging diseases like cancer. This review summarizes the synthesis and design of stimuli-responsive release strategies of MSNP-based drug delivery systems along with investigations in biomedical applications.

Alizarin-based molecular probes for the detection of hydrogen peroxide and peroxynitrite

Phenol fluorophores are a large family of fluorophores, which have attracted more and more attention in the design of probes.

Tailoring of silica-based nanoporous pod by spermidine multi-activity

Ubiquitous in nature, polyamines (PAs) are a class of low-molecular aliphatic amines critically involved in cell growth, survival and differentiation. The polycation behavior is validated as a successful strategy in delivery systems to enhance oligonucleotide loading and cellular uptake. In this study, the chemical features and the functional roles of the PA spermidine are synergistically exploited in the synthesis and bioactive functionalization of SiO2-based structures. Inspired by biosilicification, the role of spermidine is assessed both as catalyst and template in a biomimetic one-pot synthesis of dense silica-based particles (SPs) and as a competitive agent in an interfacial reassembly strategy, to empty out SPs and generate spermidine-decorated hollow silica nanoporous pods (spd-SNPs). Spermidine bioactivity is then employed for targeting tumor cell over-expressed polyamine transport system (PTS) and for effective delivery of functional miRNA into melanoma cells. Spermidine decoration promotes spd-SNP cell internalization mediated by PTS and along with hollow structure enhances oligonucleotide loading. Accordingly, the functional delivery of the tumor suppressor miR-34a 3p resulted in intracellular accumulation of histone-complexed DNA fragments associated with apoptosis. Overall, the results highlight the potential of spd-SNP as a multi-agent anticancer therapy.

Chitosan-Gated Fluorescent Mesoporous Silica Nanocarriers for the Real-Time Monitoring of Drug Release

We have constructed a novel gated nanocarrier for the real-time monitoring of drug release, consisting of three parts: (i) mesoporous silica nanoparticles (MSNs) as the drug carrier, (ii) chitosan as the nanovalve to block and unlock the pores, and (iii) 1,8-naphthalimide fluorophore as a connecting arm and fluorescent signal source. In the absence of glutathione (GSH), the integrity of the system results in the formation of pores in a closed state and the sulfone would block the intramolecular charge transfer (ICT) process, leading to no fluorescence emission. However, the nucleophilic attack of GSH can cause the removal of the chitosan and recovery of ICT property, thus triggering drug release and green fluorescence emission. The results demonstrate that the change of GSH concentration in vivo or vitro would lead to a change in drug release as well as a concurrent change in fluorescence signal, which can expand the application of our gated nanocarrier for monitoring different drug release in real time.

Biologically Inspired and Chemically Derived Methods for Glucose-Responsive Insulin Therapy

The controlled delivery of therapeutics in a manner responsive to physiological indicators has promise in realizing new therapeutic approaches to combat disease. This approach is especially relevant in the context of diabetes. Natural fluctuations in blood glucose seen in the healthy state, complete with peaks and troughs, are poorly regulated as a result of detrimental production or ineffective signaling of the insulin hormone. While several manifestations of diabetes are treated with regularly administered exogenous insulin, the present standard of care results in suboptimal glycemic management that poorly recreates natural hormone control, leading to long-term instability and a significantly increased risk for secondary health complications. New synthetic technologies that make insulin available only when needed, and at the exact dose required, have been explored under the broad vision of realizing a "fully synthetic pancreas." Yet, many challenges remain to realizing a technology that is appropriately responsive, safe, and well integrated into a manageable routine. Herein, many of the approaches explored thus far to sense physiological blood glucose and elicit response through the release of therapeutic insulin are summarized. The approaches point to a new, autonomous approach to managing diabetes with biomimetic therapy.

Advances in mesoporous silica nanoparticles for targeted stimuli-responsive drug delivery: an update

INTRODUCTION

Mesoporous silica nanoparticles (MSNs) are outstanding nanoplatforms for drug delivery. Herein, the most recent advances to turn MSN-based carriers into minimal side effect drug delivery agents are covered.

AREAS COVERED

This review summarizes the scientific advances dealing with MSNs for targeted and stimuli-responsive drug delivery since 2015. Delivery aspects to diseased tissues together with approaches to obtain smart MSNs able to respond to internal or external stimuli and their applications are here described. Special emphasis is done on the combination of two or more stimuli on the same nanoplatform and on combined drug therapy.

EXPERT OPINION

The use of MSNs in nanomedicine is a promising research field because they are outstanding platforms for treating different pathologies. This is possible thanks to their structural, chemical, physical and biological properties. However, there are certain issues that should be overcome to improve the suitability of MSNs for clinical applications. All materials must be properly characterized prior to their in vivo evaluation; furthermore, preclinical in vivo studies need to be standardized to demonstrate the MSNs clinical translation potential.

Wetting transition in nanochannels for biomimetic free-blocking on-demand drug transport

Water wetting behavior in nanometer dimensions is of great importance to the signal transmission and substance transport of organisms, e.g., aquaporins on cell membranes. A biological channel can control the transport of water and ions by regulating channel wettability, which results from the transition between the intrinsic hydrophobic state and the stimulus-induced hydration state. Inspired by aquaporins in nature, herein, a biomimetic free-blocking on-demand delivery system is proposed, which is constructed by controlling the wettability of the inner surface of nanochannels of mesoporous silica nanoparticles (MSNs). Such a system is completely different from the traditional physically occluding pore controlled release system. It circumvents the use of other extra capping agents, thus overcoming the limitations of the traditional nano "gate" blockage system with inherent instability, poor plugging capability and low biocompatibility. Additionally, further applications in drug delivery have shown that this system can selectively release entrapped drugs in beta cells triggered by intracellular glucose in a controlled manner but not in normal cells. This hydrophobic gating drug delivery system with simple and effective performance provides a new opportunity for constructing a mass transport platform from the perspective of surface wettability.

Mesoporous Silica Nanoparticles: A Comprehensive Review on Synthesis and Recent Advances

Recent advancements in drug delivery technologies utilizing a variety of carriers have resulted in a path-breaking revolution in the approach towards diagnosis and therapy alike in the current times. Need for materials with high thermal, chemical and mechanical properties have led to the development of mesoporous silica nanoparticles (MSNs). These ordered porous materials have garnered immense attention as drug carriers owing to their distinctive features over the others. They can be synthesized using a relatively simple process, thus making it cost effective. Moreover, by controlling the parameters during the synthesis; the morphology, pore size and volume and particle size can be transformed accordingly. Over the last few years, a rapid increase in research on MSNs as drug carriers for the treatment of various diseases has been observed indicating its potential benefits in drug delivery. Their widespread application for the loading of small molecules as well as macromolecules such as proteins, siRNA and so forth, has made it a versatile carrier. In the recent times, researchers have sorted to several modifications in the framework of MSNs to explore its potential in drug resistant chemotherapy, antimicrobial therapy. In this review, we have discussed the synthesis of these multitalented nanoparticles and the factors influencing the size and morphology of this wonder carrier. The second part of this review emphasizes on the applications and the advances made in the MSNs to broaden the spectrum of its use especially in the field of biomedicine. We have also touched upon the lacunae in the thorough understanding of its interaction with a biological system which poses a major hurdle in the passage of this carrier to the clinical level. In the final part of this review, we have discussed some of the major patents filed in the field of MSNs for therapeutic purpose.

Applications of mesoporous silica in biosensing and controlled release of insulin

The development of new oral insulin delivery systems could bring significant benefits to insulin-dependent patients due to the simplicity of the method, avoidance of pain caused by parenteral administration and maintenance of optimal therapeutic levels for a longer period. However, administration of such therapeutic proteins orally remains a challenge because insulin (Ins) is a very sensitive molecule and can be easily degraded under the existing pH conditions in the stomach and intestines. Moreover, due to the large size of insulin, intestinal epithelium permeability is very low. This could be improved by immobilizing insulin in the mesoporous silica pores (MSN), acting as a shield to protect the molecule integrity from the proteolytic degradation existing in the stomach and upper part of the small intestine. Due to the high adsorption capacity of insulin, biocompatibility, ease of functionalization with various organic and/or inorganic groups, high mechanical and chemical resistance, adjustable pore size and volume, MSN is considered an ideal candidate for the development of controlled release systems that are sensitive to various stimuli (pH, temperature) as well as to glucose. Modifying MSN surfaces by coating with various mucoadhesive polymers (chitosan, alginate, etc.) will also facilitate interaction with the intestinal mucus and improve intestinal retention time. Moreover, the development of glucose-responsive systems for achieving MSN-based self-regulated insulin delivery, decorated with various components serving as sensors - glucose oxidase (GOD_x) and phenylboronic acid (PBA) that can control the insulin dosage, avoiding overdose leading to serious hypoglycemia. MSN have also been tested for application as biosensors for glucose monitoring.

Encoding materials for programming a temporal sequence of actions

Materials are usually synthesized to allow a function that is either independent of time or that can be triggered in a specific environment.

Silica-based systems for oral delivery of drugs, macromolecules and cells

According to the US Food and Drug Administration and the European Food Safety Authority, amorphous forms of silica and silicates are generally recognized to be safe as oral delivery ingredients in amounts up to 1500mg per day. Silica is used in the formulation of solid dosage forms, e.g. tablets, as glidant or lubricant. The synthesis of silica-based materials depends on the payload nature, drug, macromolecule or cell, and on the target release (active or passive). In the literature, most of the examples deal with the encapsulation of drugs in mesoporous silica nanoparticles. Still to date limited reports concerning the delivery of encapsulated macromolecules and cells have been reported in the field of oral delivery, despite the multiple promising examples demonstrating the compatibility of the sol-gel route with biological entities, likewise the interest of silica as an oral carrier. Silica diatoms appear as an elegant, cost-effective and promising alternative to synthetic sol-gel-based materials. This review reports the latest advances silica-based systems and discusses the potential benefits and drawbacks of using silica for oral delivery of drugs, macromolecules or cells.

Encapsulation of 16-Hydroxycleroda-3,13-Dine-16,15-Olide in Mesoporous Silica Nanoparticles as a Natural Dipeptidyl Peptidase-4 Inhibitor Potentiated Hypoglycemia in Diabetic Mice

Natural supplements comprise good efficacy with less adverse effects as against diabetic therapy, but their advancement as anti-diabetic agents is unsatisfactory with regard to the delivery system. Dipeptidyl peptidase-4 (DPP4)/CD26) can degrade glucagon-like pepetide-1 (GLP-1) which renders a decrease of blood glucose levels. 16-hydroxycleroda-3,13-dine-16,15-olide (HCD) extracted from Polyalthia longifolia, exhibits numerous medicinal potentials including hypoglycemic potential. On consideration of HCD application, the bioavailability is affected by low solubility. Extended experiments of anti-diabetic efficacy confirmed HCD biocompatible with mesoporous silica nanoparticles (MSNs) encapsulation resulted in a sustained release property in delivering HCD for the inhibition of DPP4 via the activity and protein levels of DPP4 analysis. In the enzymatic activity assay, MSN-HCD directly changed DPP4 activity. Moreover, MSN-HCD nanoparticles were treated with Caco-2 cells and the protein levels of DPP4 determined within the cells. The results revealed that MSN-HCD caused reduction of DPP4 activity in a time- and dose-dependent fashion. Orally administered MSN-HCD in diet-induced diabetic mice alleviated blood glucose via an oral glucose tolerance test. In addition, administration of MSN-HCD for five weeks revealed that the biochemical cues such as pyruvate transaminase (GPT), glutamate oxaloacetate transaminase (GOT), triglycerides (TG), cholesterol (CHO), and glycated hemoglobin (HbA1c) in mice were commendable as further confirmation of MSN-HCD efficacy and less adverse effects in down-regulation of hyperglycemia. Furthermore, this formulation effectively controlled blood glucose and significantly decreased the body weight of mice, suggesting that MSN-HCD exerts natural DPP4 inhibitor as a potential clinical drug for the treatment of diabetes.

Multifunctional nanoparticle composites: progress in the use of soft and hard nanoparticles for drug delivery and imaging

With continued advancements in nanoparticle (NP) synthesis and in the interfacing of NPs with biological systems has come the exponential growth in the use of NPs for therapeutic drug delivery and imaging applications. In recent years, the advent of NP multifunctionality-the ability to perform multiple, disparate functions on a single NP platform-has garnered much excitement for the potential realization of highly functional NP-mediated drug delivery for use in the clinical setting. This Overview will survey the current state of the art (reports published within the last 5 years) of multifunctional NPs for therapeutic drug delivery, imaging or a combination thereof. We provide extensive examples of both soft (micelles, liposomes, polymeric NPs) and hard (noble metals, quantum dots, metal oxides) NP formulations that have been used for multimodal drug delivery and imaging. The criteria for inclusion, herein, is that there must be at least two therapeutic drug cargos or imaging agents or a combination of the two. We next offer an assessment of the cytotoxicity of therapeutic NP constructs in biological systems. We then conclude with a forward-looking perspective on how we expect this field to develop in the coming years. WIREs Nanomed Nanobiotechnol 2017, 9:e1466. doi: 10.1002/wnan.1466 For further resources related to this article, please visit the WIREs website.

Boronic Acid as Glucose-Sensitive Agent Regulates Drug Delivery for Diabetes Treatment

In recent years, glucose-sensitive drug delivery systems have attracted considerable attention in the treatment of diabetes. These systems can regulate payload release by the changes of blood glucose levels continuously and automatically with potential application in self-regulated drug delivery. Boronic acid (BA), especially phenylboronic acid (PBA), as glucose-sensitive agent has been the focus of research in the design of glucose-sensitive platforms. This article reviews the previous attempts at the developments of PBA-based glucose-sensitive drug delivery systems regarding the PBA-functionalized materials and glucose-triggered drug delivery. The obstacles and potential developments of glucose-sensitive drug delivery systems based on PBA for diabetes treatment in the future are also described. The PBA-functionalized platforms that regulate drug delivery induced by glucose are expected to contribute significantly to the design and development of advanced intelligent self-regulated drug delivery systems for treatment of diabetes.

Polypeptide-participating complex nanoparticles with improved salt-tolerance as excellent candidates for intelligent insulin delivery

The strategy of introducing synthetic polypeptides with hierarchical ordered structures into glucose-responsive materials is reported in this study to achieve self-regulated release of insulin under physiological salt concentration.