Stochastic Model of Virus–Endosome Fusion and Endosomal Escape of pH-Responsive Nanoparticles

In this paper, we set up a stochastic model for the dynamics of active Rab5 and Rab7 proteins on the surface of endosomes and the acidification process that govern the virus–endosome fusion and endosomal escape of pH-responsive nanoparticles. We employ a well-known cut-off switch model for Rab5 to Rab7 conversion dynamics and consider two random terms: white Gaussian and Poisson noises with zero mean. We derive the governing equations for the joint probability density function for the endosomal pH, Rab5 and Rab7 proteins. We obtain numerically the marginal density describing random fluctuations of endosomal pH. We calculate the probability of having a pH level inside the endosome below a critical threshold and therefore the percentage of viruses and pH-responsive nanoparticles escaping endosomes. Our results are in good qualitative agreement with experimental data on viral escape.

Shell-Sheddable Micelles Based on Poly(ethylene glycol)-hydrazone-poly[R,S]-3-hydroxybutyrate Copolymer Loaded with 8-Hydroxyquinoline Glycoconjugates as a Dual Tumor-Targeting Drug Delivery System

The development of selective delivery of anticancer drugs into tumor tissues to avoid systemic toxicity is a crucial challenge in cancer therapy. In this context, we evaluated the efficacy of a combination of nanocarrier pH-sensitivity and glycoconjugation of encapsulated drugs, since both vectors take advantage of the tumor-specific Warburg effect. Herein, we synthesized biodegradable diblock copolymer, a poly(ethylene glycol)-hydrazone linkage-poly[R,S]-3-hydroxybutyrate, which could further self-assemble into micelles with a diameter of ~55 nm. The hydrazone bond was incorporated between two copolymer blocks under an acidic pH, causing the shell-shedding of micelles which results in the drug's release. The micelles were stable at pH 7.4, but decompose in acidic pH, as stated by DLS studies. The copolymer was used as a nanocarrier for 8-hydroxyquinoline glucose and galactose conjugates as well as doxorubicin, and exhibited pH-dependent drug release behavior. In vitro cytotoxicity, apoptosis, and life cycle assays studies of blank and drug-loaded micelles were performed on Normal Human Dermal Fibroblasts-Neonatal (NHDF-Neo), colon carcinoma (HCT-116), and breast cancer (MCF-7) for 24, 48, and 72 h. A lack of toxicity of blank micelles was demonstrated, whereas the glycoconjugates-loaded micelles revealed enhanced selectivity to inhibit the proliferation of cancer cells. The strategy of combining pH-responsive nanocarriers with glycoconjugation of the drug molecule provides an alternative to the modus operandi of designing multi-stimuli nanocarriers to increase the selectivity of anticancer therapy.

Quantifying the Endosomal Escape of pH-Responsive Nanoparticles Using the Split Luciferase Endosomal Escape Quantification Assay

All nanoparticles have the potential to revolutionize the delivery of therapeutic cargo such as peptides, proteins, and RNA. However, effective cytosolic delivery of cargo from nanoparticles represents a significant challenge in the design of more efficient drug delivery vehicles. Recently, research has centered on designing nanoparticles with the capacity to escape endosomes by responding to biological stimuli such as changes in pH, which occur when nanoparticles are internalized into the endo-/lysosomal pathway. Current endosomal escape assays rely on indirect measurements and yield little quantitative information, which hinders the design of more efficient drug delivery vehicles. Therefore, we adapted the highly sensitive split luciferase endosomal escape quantification (SLEEQ) assay to better understand nanoparticle-induced endosomal escape. We applied SLEEQ to evaluate the endosomal escape behavior of two pH-responsive nanoparticles: the first with a poly(2-diisopropylamino ethyl methacrylate) (PDPAEMA) core and the second with 1:1 ratio of poly(2-diethylamino ethyl methacrylate) (PDEAEMA) and PDPAEMA. SLEEQ directly measured the cytosolic delivery and showed that engineering the nanoparticle disassembly pH could improve the endosomal escape efficiency by fivefold. SLEEQ is a versatile assay that can be used for a wide range of nanomaterials and will improve the development of drug delivery vehicles in the future.

Activation of Antibiotic-Grafted Polymer Brushes by Ultrasound

The ultrasound-mediated activation of drugs from macromolecular architectures using the principles of polymer mechanochemistry (sonopharmacology) is a promising strategy to gain spatiotemporal control over drug activity. Yet, conceptual challenges limit the applicability of this method. Especially low drug-loading content and low mechanochemical efficiency require the use of high carrier mass concentrations and prolonged exposure to ultrasound. Moreover, the activated drug is generally shielded by the hydrodynamic coil of the attached polymer fragment leading to a decreased drug potency. Here we present a carrier design for the ultrasound-induced activation of vancomycin, which is deactivated with its H-bond-complementary peptide target sequence. We show that the progression from mechanophore-centered linear chains to mechanophore-decorated polymer brushes increases drug-loading content, mechanochemical efficiency, and drug potency. These results may serve as a design guideline for future endeavors in the field of sonopharmacology.

Application of molecular docking in elaborating molecular mechanisms and interactions of supramolecular cyclodextrin

The cyclodextrin (CD)-based supramolecular nanomedicines have attracted growing interest because of their superior characteristics, including desirable biocompatibility, low toxicity, unique molecular structure and easy functionalization. The smart structures of CD impart host-guest interaction for meeting the multifunctional needs of disease therapy. However, it faces challenges in formulation design and inclusion mechanism clarification of the functional supramolecular assemblies owing to the complicated structures and mechanisms. Fortunately, molecular docking helps the researchers to comprehend the interaction between the drug and the target molecule for achieving high-through screening from the database. In this review, we summarized the category and characteristics of molecular docking along with the properties and applications of CD. Significantly, we highlighted the application of molecular docking in elaborating molecular mechanisms and simulating complex structures at molecular levels. The issues and development of CD and molecular docking were also presented to provide beneficial reference and new insights for supramolecular nano-systems.

Crosslinking-Dependent Drug Kinetics in Hydrogels for Ophthalmic Delivery

Drug-diffusion kinetics in 2-hydroxyethyl methacrylate hydrogels were studied as a function of the crosslinking density and porosity. By varying the concentration of the crosslinker, tetraethylene glycol dimethacrylate, we demonstrated how the release of Timolol maleate could be optimized to allow for efficient drug delivery. FTIR and spectrophotometry supplied optical inferences into the functional groups present. By studying the swelling and degradation of hydrogels, supplemented with drug-release kinetics studies, the relationship between these two tenets could be formulated.

Functional pH-responsive polymers containing dynamic enaminone linkages for the release of active organic amines

Dynamic covalent bonds have attracted attention for the development of pH-responsive polymers, however, studies using acid-cleavable enaminone linkages as a means of controlled drug release have been limited. Herein, we...

Synthesis of multiple stimuli-responsive degradable block copolymers via facile carbonyl imidazole-induced postpolymerization modification

A robust approach that centers on carbonyl imidazole chemistry was used to synthesize a triple-stimuli-responsive degradable block copolymer labeled with acetal, disulfide, and o-nitrobenzyl groups exhibiting acid, reduction, and light responses.

Engineered Aptamer-Organic Amphiphile Self-Assemblies for Biomedical Applications: Progress and Challenges

Currently, nucleic acid aptamers are exploited as robust targeting ligands in the biomedical field, due to their specific molecular recognition, little immunogenicity, low cost, ect. Thanks to the facile chemical modification and high hydrophilicity, aptamers can be site-specifically linked with hydrophobic moieties to prepare aptamer-organic amphiphiles (AOAs), which spontaneously assemble into aptamer-organic amphiphile self-assemblies (AOASs). These polyvalent self-assemblies feature with enhanced target-binding ability, increased resistance to nuclease, and efficient cargo-loading, making them powerful platforms for bioapplications, including targeted drug delivery, cell-based cancer therapy, biosensing, and bioimaging. Besides, the morphology of AOASs can be elaborately manipulated for smarter biomedical functions, by regulating the hydrophilicity/hydrophobicity ratio of AOAs. Benefiting from the boom in DNA synthesis technology and nanotechnology, various types of AOASs, including aptamer-polymer amphiphile self-assemblies, aptamer-lipid amphiphile self-assemblies, aptamer-cell self-assemblies, ect, have been constructed with great biomedical potential. Particularly, stimuli-responsive AOASs with transformable structure can realize site-specific drug release, enhanced tumor penetration, and specific target molecule detection. Herein, the general synthesis methods of oligonucleotide-organic amphiphiles are firstly summarized. Then recent progress in different types of AOASs for bioapplications and strategies for morphology control are systematically reviewed. The present challenges and future perspectives of this field are also discussed.

Nanoparticles for vaccine and gene therapy: Overcoming the barriers to nucleic acid delivery

Nucleic acid therapeutics can be used to control virtually every aspect of cell behavior and therefore have significant potential to treat genetic disorders, infectious diseases, and cancer. However, while clinically approved to treat a small number of diseases, the full potential of nucleic acid therapeutics is hampered by inefficient delivery. Nucleic acids are large, highly charged biomolecules that are sensitive to degradation and so the approaches to deliver these molecules differ significantly from traditional small molecule drugs. Current studies suggest less than 1% of the injected nucleic acid dose is delivered to the target cell in an active form. This inefficient delivery increases costs and limits their use to applications where a small amount of nucleic acid is sufficient. In this review, we focus on two of the major barriers to efficient nucleic acid delivery: (1) delivery to the target cell and (2) transport to the subcellular compartment where the nucleic acids are therapeutically active. We explore how nanoparticles can be modified with targeting ligands to increase accumulation in specific cells, and how the composition of the nanoparticle can be engineered to manipulate or disrupt cellular membranes and facilitate delivery to the optimal subcellular compartments. Finally, we highlight how with intelligent material design, nanoparticle delivery systems have been developed to deliver nucleic acids that silence aberrant genes, correct genetic mutations, and act as both therapeutic and prophylactic vaccines. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Stimuli-responsive nanomaterials for cancer treatment: boundaries, opportunities and applications

Small molecule drugs, including most chemotherapies, are rapidly degraded and/or eliminated from the body, which is why high doses of these drugs are necessary, potentially producing toxic effects. Several types of nanoparticles loaded with anti-cancer drugs have been designed to overcome the disadvantages of conventional therapies. Modified nanoparticles can circulate for a long time, thus improving the solubility and biodistribution of drugs. Furthermore, they also allow the controlled release of the payload once its target tissue has been reached. These mechanisms can reduce the exposure of healthy tissues to chemotherapeutics, since the drugs are only released in the presence of specific tumour stimuli. Overall, these properties can improve the effectiveness of treatments while reducing undesirable side effects. In this article, we review the recent advances in stimuli-responsive albumin, gold and magnetic nanostructures for controlled anti-cancer drug delivery. These nanostructures were designed to release drugs in response to different internal and external stimuli of the cellular environment, including pH, redox, light and magnetic fields. We also describe various examples of applications of these nanomaterials. Overall, we shed light on the properties, potential clinical translation and limitations of stimuli-responsive nanoparticles for cancer treatment.

Tumor microenvironment based stimuli-responsive CRISPR/Cas delivery systems: A viable platform for interventional approaches

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems have emerged as robust tools in cancer gene therapy due to their simplicity and versatility. Nevertheless, the genome editing efficiency in tumor sites and the clinical applications of CRISPR/Cas have been compromised by non-specific delivery and genotoxicity. Recently, intelligent delivery systems incorporating sensitive materials in response to endogenous stimuli of the tumor microenvironment (TME) have represented viable platforms for tumor-specific genome editing and reduced side effects of CRISPR/Cas. Spurred by this promising direction, this review first introduces the CRISPR/Cas systems widely employed in cancer therapeutic explorations. Various types of CRISPR/Cas delivery systems sensitive to the stimuli in TME and typical dual-/multiple-responsive CRISPR/Cas carriers are further discussed, emphasizing the correlations between sensitive components and spatiotemporal delivery mechanisms. The genome editing efficiencies of CRISPR/Cas-loaded stimuli-responsive carriers are also summarized both in vitro and in vivo. Collectively, stimuli-responsive CRISPR/Cas delivery systems hold great promise for potent cancer gene therapy.

Design and fabrication of hybrid triple-responsive κ-carrageenan-based nanospheres for controlled drug delivery

In the last two decades, the utilization of magnetic nanospheres in intelligent polymeric structures have received increased attention of researchers in numerous biomedical applications. Here, hybrid nanostructured triple-responsive magnetic nanospheres (κ-Car-g-P(AA/DMA)@Fe₃O₄) containing inorganic iron oxide core (Fe₃O₄) and organic graft copolymeric shell based on κ-carrageenan (κ-Car) and poly(acrylic acid/dimethylaminoethyl methacrylate) (P(AA/DMA)) were synthesized by microwave induced co-precipitation technique. The structure, size, surface morphology, magnetic property and stability of synthesized κ-Car-g-P(AA/DMA)@Fe₃O₄ magnetic nanospheres were characterized using FTIR, UV, XRD, TEM, Zeta-sizer, and VSM. κ-Car-g-P(AA/DMA)@Fe₃O₄ nanospheres were loaded with 5-Fluorouracil (5-FU) as an antineoplastic drug, and their 5-FU release behavior was explored in diverse graft yields, pH values, temperatures and in the existence of an alternating magnetic field. The κ-Car-g-P(AA/DMA)@Fe₃O₄ nanospheres demonstrated pH-, thermo-, and magnetic field-responsive 5-FU release with good biocompatibility and excellent anticancer activity. In addition, 5-FU release under 50 mT magnetic field reached to 100% within 4 h. This work exhibits that hybrid nanospheres have a triple stimuli-responsive influence, which is of principal importance for the future design and application of multi-functional responsive platforms to develop externally stimulated release of active agents and their healthcare capability.

Stimuli-Responsive Polymeric Nanomaterials for the Delivery of Immunotherapy Moieties: Antigens, Adjuvants and Agonists

Immunotherapy has been investigated for decades, and it has provided promising results in preclinical studies. The most important issue that hinders researchers from advancing to clinical studies is the delivery system for immunotherapy agents, such as antigens, adjuvants and agonists, and the activation of these agents at the tumour site. Polymers are among the most versatile materials for a variety of treatments and diagnostics, and some polymers are reactive to either endogenous or exogenous stimuli. Utilizing this advantage, researchers have been developing novel and effective polymeric nanomaterials that can deliver immunotherapeutic moieties. In this review, we summarized recent works on stimuli-responsive polymeric nanomaterials that deliver antigens, adjuvants and agonists to tumours for immunotherapy purposes.

Polymer-Based Nanosystems-A Versatile Delivery Approach

Polymer-based nanoparticles of tailored size, morphology, and surface properties have attracted increasing attention as carriers for drugs, biomolecules, and genes. By protecting the payload from degradation and maintaining sustained and controlled release of the drug, polymeric nanoparticles can reduce drug clearance, increase their cargo's stability and solubility, prolong its half-life, and ensure optimal concentration at the target site. The inherent immunomodulatory properties of specific polymer nanoparticles, coupled with their drug encapsulation ability, have raised particular interest in vaccine delivery. This paper aims to review current and emerging drug delivery applications of both branched and linear, natural, and synthetic polymer nanostructures, focusing on their role in vaccine development.

A New pH-Responsive Nano Micelle for Enhancing the Effect of a Hydrophobic Bactericidal Agent on Mature Streptococcus mutans Biofilm

The bactericidal effect on biofilm is the main challenge currently faced by antibacterial agents. Nanoscale drug-delivery materials can enhance biofilm penetrability and drug bioavailability, and have significant applications in the biomedical field. Dental caries is a typical biofilm-related disease, and the acidification of biofilm pH is closely related to the development of dental caries. In this study, a pH-responsive core-shell nano micelle (mPEG-b-PDPA) capable of loading hydrophobic antibacterial agents was synthesized and characterized, including its ability to deliver antibacterial agents within an acidic biofilm. The molecular structure of this diblock copolymer was determined by hydrogen-1 nuclear magnetic resonance (¹H-NMR) and gel permeation chromatography (GPC). The characters of the micelles were studied by dynamic light scattering (DLS), TEM, pH titration, and drug release detection. It was found that the hydrophilic micelles could deliver bedaquiline, a hydrophobic antibacterial agent on S. mutans, in acidic environments and in mature biofilm. No cytotoxic effect on the periodontal cells was detected within 48 h. This pH-responsive micelle, being able to load hydrophobic antibacterial agent, has good clinical application potential in preventing dental caries.

Development of next generation nanomedicine-based approaches for the treatment of cancer: we've barely scratched the surface

Interest in nanomedicines has grown rapidly over the past two decades, owing to the promising therapeutic applications they may provide, particularly for the treatment of cancer. Personalised medicine and 'smart' actively targeted nanoparticles represent an opportunity to deliver therapies directly to cancer cells and provide sustained drug release, in turn providing overall lower off-target toxicity and increased therapeutic efficacy. However, the successful translation of nanomedicines from encouraging pre-clinical findings to the clinic has, to date, proven arduous. In this review, we will discuss the use of nanomedicines for the treatment of cancer, with a specific focus on the use of polymeric and lipid nanoparticle delivery systems. In particular, we examine approaches exploring the surface functionalisation of nanomedicines to elicit active targeting and therapeutic effects as well as challenges and future directions for nanoparticles in cancer treatment.

The Urokinase Receptor (uPAR) as a "Trojan Horse" in Targeted Cancer Therapy: Challenges and Opportunities

Simple Summary

Discovered more than three decades ago, the urokinase-type plasminogen activator receptor (uPAR) has now firmly established itself as a versatile molecular target holding promise for the treatment of aggressive malignancies. The copious abundance of uPAR in virtually all human cancerous tissues versus their healthy counterparts has fostered a gradual shift in the therapeutic landscape targeting this receptor from function inhibition to cytotoxic approaches to selectively eradicate the uPAR-expressing cells by delivering a targeted cytotoxic insult. Multiple avenues are being explored in a preclinical setting, including the more innovative immune- or stroma targeting therapies. This review discusses the current state of these strategies, their potentialities, and challenges, along with future directions in the field of uPAR targeting.

Abstract

One of the largest challenges to the implementation of precision oncology is identifying and validating selective tumor-driving targets to enhance the therapeutic efficacy while limiting off-target toxicity. In this context, the urokinase-type plasminogen activator receptor (uPAR) has progressively emerged as a promising therapeutic target in the management of aggressive malignancies. By focalizing the plasminogen activation cascade and subsequent extracellular proteolysis on the cell surface of migrating cells, uPAR endows malignant cells with a high proteolytic and migratory potential to dissolve the restraining extracellular matrix (ECM) barriers and metastasize to distant sites. uPAR is also assumed to choreograph multiple other neoplastic stages via a complex molecular interplay with distinct cancer-associated signaling pathways. Accordingly, high uPAR expression is observed in virtually all human cancers and is frequently associated with poor patient prognosis and survival. The promising therapeutic potential unveiled by the pleiotropic nature of this receptor has prompted the development of distinct targeted intervention strategies. The present review will focus on recently emerged cytotoxic approaches emphasizing the novel technologies and related limits hindering their application in the clinical setting. Finally, future research directions and emerging opportunities in the field of uPAR targeting are also discussed.

Construction and antitumor properties of a targeted nano-drug carrier system responsive to the tumor microenvironment

Doxorubicin (DOX) is one of the most commonly used and effective chemotherapy drugs among anthracyclines. An inherent limitation of DOX is its nonspecificity, which can cause serious side effects, thereby preventing the therapeutic use of high drug doses. In this study, we designed and created a simple nano-drug delivery system (PEG-MAF = P) with low biological toxicity that was responsive to the tumor environment. PEG-MAF = P was designed to self-assemble into nanospheres via control of a phenylalanine dipeptide (FF). The N-terminus of the peptide was linked to aldehyde groups at both ends of oxidized Pluronic F127 (F127-CHO) via Schiff bonds. The acidic environment surrounding the tumors was suitable for triggering the Schiff bonds, causing the nanospheres to disintegrate. The C-terminus of FF was connected to a ligand peptide, ATN-161, which was able to recognize cells expressing high levels of integrin α5β1 antigens both in vivo and in vitro. To prevent the impediment in drug release, PEG was linked via a matrix metalloproteinase-9 response peptide. Therefore, in an acidic tumor microenvironment containing MMP-9, PEG-MAF = P disintegrated and rapidly released the drug. PEG-MAF = P exhibited low cytotoxicity, high drug-loading rate, and excellent antitumor properties both in vivo and in vitro. Compared with free DOX, PEG-MAF = P-DOX reduced injury to normal tissues.

Controlling the semi-permeability of protein nanocapsules influences the cellular response to macromolecular payloads

Nanocapsules are an excellent platform for the delivery of macromolecular payloads such as proteins, nucleic acids or polyprodrugs, since they can both protect the sensitive cargo and target its delivery to the desired site of action. However, the release of macromolecules from nanocapsules remains a challenge due to their restricted diffusion through the nanoshell compared to small molecule cargo. Here, we designed degradable protein nanocapsules with varying crosslinking densities of the nanoshell to control the release of model macromolecules. While the crosslinking did not influence the degradability of the capsules by natural proteases, it significantly affected the release profiles. Furthermore, the optimized protein nanocapsules were successfully used to deliver and effectively release a bioactive macromolecular vaccine adjuvant in vitro and, thus, can be used as an efficient platform for the design of potential nanovaccines.

Stimuli-Responsive Polymeric Nanosystems for Controlled Drug Delivery

Biocompatible nanosystems based on polymeric materials are promising drug delivery nanocarrier candidates for antitumor therapy. However, the efficacy is unsatisfying due to nonspecific accumulation and drug release of the nanoparticles in normal tissue. Recently, the nanosystems that can be triggered by tumor-specific stimuli have drawn great interest for drug delivery applications due to their controllable drug release properties. In this review, various polymers and external stimuli that can be employed to develop stimuli-responsive polymeric nanosystems are discussed, and finally, we delineate the challenges in designing this kind of Nanomedicine to improve the therapeutic efficacy.

Breaking Isolation to Form New Networks: pH-Triggered Changes in Connectivity inside Lipid Nanoparticles

There is a growing demand to develop smart nanomaterials that are structure-responsive as they have the potential to offer enhanced dose, temporal and spatial control of compounds and chemical processes. The naturally occurring pH gradients found throughout the body make pH an attractive stimulus for guiding the response of a nanocarrier to specific locations or (sub)cellular compartments in the body. Here we have engineered highly sensitive lyotropic liquid crystalline nanoparticles that reversibly respond to changes in pH by altering the connectivity within their structure at physiological temperatures. At pH 7.4, the nanoparticles have an internal structure consisting of discontinuous inverse micellar "aqueous pockets" based on space group Fd3m. When the pH is ≤6, the nanoparticles change from a compartmentalized to an accessible porous internal structure based on a 2D inverse hexagonal phase (plane group p6mm). We validate the internal symmetry of the nanoparticles using small-angle X-ray scattering and cryogenic transmission electron microscopy. The high-resolution electron microscopy images obtained have allowed us for the first time to directly visualize the internal structure of the Fd3m nanoparticles and resolve the two different-sized inverse micelles that make up the structural motif within the Fd3m unit cell, which upon structural analysis reveal excellent agreement with theoretical geometrical models.

Mechanical computing

Mechanical mechanisms have been used to process information for millennia, with famous examples ranging from the Antikythera mechanism of the Ancient Greeks to the analytical machines of Charles Babbage. More recently, electronic forms of computation and information processing have overtaken these mechanical forms, owing to better potential for miniaturization and integration. However, several unconventional computing approaches have recently been introduced, which blend ideas of information processing, materials science and robotics. This has raised the possibility of new mechanical computing systems that augment traditional electronic computing by interacting with and adapting to their environment. Here we discuss the use of mechanical mechanisms, and associated nonlinearities, as a means of processing information, with a view towards a framework in which adaptable materials and structures act as a distributed information processing network, even enabling information processing to be viewed as a material property, alongside traditional material properties such as strength and stiffness. We focus on approaches to abstract digital logic in mechanical systems, discuss how these systems differ from traditional electronic computing, and highlight the challenges and opportunities that they present.

Cascade Release Nanocarriers for the Triple-Negative Breast Cancer Near-Infrared Imaging and Photothermal-Chemo Synergistic Therapy

Triple-negative breast cancer (TNBC) has inadequate treatment approaches and a poor prognosis. It is urgent to develop new treatment approaches for TNBC. The combination of photothermal therapy (PTT) and chemotherapy is a very effective potential therapy for TNBC. However, asynchronous accumulation, unclear efficacy, and toxic side effects hinder the further promotion of this method. Therefore, we designed and constructed a new type of nanocarriers, the cascade release near-infrared imaging (NIFI) & thermal-chemo combination nanoparticles (CNC NPs), that can release drugs through the cascade of ultrasound triggering and pH responding to achieve the synchronous tumor accumulation, monitoring and synergistic treatment of two functional molecules. The key material of CNC NPs is the polydopamine (PDA), which, through self-assembling, forms a rigid shell that contains doxorubicin (DOX) and NIF fluorescent dye IR780 on the surface of the perfluorohexane (PFH) microbubbles. The results show that CNC NPs have a hollow core-shell structure with an average particle size of 97.3 ± 27.2 nm and have exceptional colloidal stability and photothermal conversion efficiency. The NPs can effectively perform cascade drug release through ultrasound triggering and pH responding. CNC NPs have good in vivo biological safety and excellent fluorescence imaging, drug delivery, and therapeutic abilities in the TNBC models. These results provide an experimental basis for the development of new clinical treatment methods for TNBC.

Wavelength-Selective Softening of Hydrogel Networks

Photoresponsive hydrogels hold key potential in advanced biomedical applications including tissue engineering, regenerative medicine, and drug delivery, as well as intricately engineered functions such as biosensing, soft robotics, and bioelectronics. Herein, the wavelength-dependent degradation of bio-orthogonal poly(ethylene glycol) hydrogels is reported, using three selective activation levels. Specifically, three chromophores are exploited, that is, ortho-nitrobenzene, dimethyl aminobenzene, and bimane, each absorbing light at different wavelengths. By examining their photochemical action plots, the wavelength-dependent reactivity of the photocleavable moieties is determined. The wavelength-selective addressability of individual photoreactive units is subsequently translated into hydrogel design, enabling wavelength-dependent cleavage of the hydrogel networks on-demand. Critically, this platform technology allows for the fabrication of various hydrogels, whose mechanical properties can be fine-tuned using different colors of light to reach a predefined value, according to the chromophore ratios used. The softening is shown to influence the spreading of pre-osteoblastic cells adhering to the gels as a demonstration of their potential utility. Furthermore, the materials and photodegradation processes are non-toxic to cells, making this platform attractive for biomaterials engineering.

Controlled Drug Delivery Systems: Current Status and Future Directions

The drug delivery system enables the release of the active pharmaceutical ingredient to achieve a desired therapeutic response. Conventional drug delivery systems (tablets, capsules, syrups, ointments, etc.) suffer from poor bioavailability and fluctuations in plasma drug level and are unable to achieve sustained release. Without an efficient delivery mechanism, the whole therapeutic process can be rendered useless. Moreover, the drug has to be delivered at a specified controlled rate and at the target site as precisely as possible to achieve maximum efficacy and safety. Controlled drug delivery systems are developed to combat the problems associated with conventional drug delivery. There has been a tremendous evolution in controlled drug delivery systems from the past two decades ranging from macro scale and nano scale to intelligent targeted delivery. The initial part of this review provides a basic understanding of drug delivery systems with an emphasis on the pharmacokinetics of the drug. It also discusses the conventional drug delivery systems and their limitations. Further, controlled drug delivery systems are discussed in detail with the design considerations, classifications and drawings. In addition, nano-drug delivery, targeted and smart drug delivery using stimuli-responsive and intelligent biomaterials is discussed with recent key findings. The paper concludes with the challenges faced and future directions in controlled drug delivery.

Natural Polymers for the Maintenance of Oral Health: Review of Recent Advances and Perspectives

The success of modern dental treatment is strongly dependent on the materials used both temporarily and permanently. Among all dental materials, polymers are a very important class with a wide spectrum of applications. This review aims to provide a state-of-the-art overview of the recent advances in the field of natural polymers used to maintain or restore oral health. It focuses on the properties of the most common proteins and polysaccharides of natural origin in terms of meeting the specific biological requirements in the increasingly demanding field of modern dentistry. The use of naturally derived polymers in different dental specialties for preventive and therapeutic purposes has been discussed. The major fields of application cover caries and the management of periodontal diseases, the fabrication of membranes and scaffolds for the regeneration of dental structures, the manufacturing of oral appliances and dentures as well as providing systems for oral drug delivery. This paper also includes a comparative characteristic of natural and synthetic dental polymers. Finally, the current review highlights new perspectives, possible future advancements, as well as challenges that may be encountered by researchers in the field of dental applications of polymers of natural origin.

Acid-Responsive Poly(glyoxylate) Self-Immolative Star Polymers

Self-immolative polymers have significant potential for applications such as drug or gene delivery. However, to realize this potential, such materials need to be customized to respond to specific variations in biological conditions. In this work, we investigated the design of new star-shaped self-immolative poly(ethyl glyoxylate)s (PEtGs) and their incorporation into responsive nanoparticles. PEtGs are a subclass of stimulus-responsive self-immolative polymers, which can be combined with different stimuli-responsive functionalities. Two different tetrathiol initiators were used for the polymerization in combination with a variety of potential pH-responsive end-caps, yielding a library of star PEtG polymers which were responsive to pH. Characterization of the depolymerization behavior of the polymers showed that the depolymerization rate was controlled by the end caps rather than the architecture of the polymer. A selection of the star polymers were modified with amines to allow introduction of charge-shifting properties. It was shown that pH-responsive nanoparticles could be prepared from these modified polymers and they demonstrated pH-dependent particle disruption. The pH responsiveness of these particles was studied by dynamic light scattering and ¹H nuclear magnetic resonance spectroscopy.

A Critical Review on Polymeric Biomaterials for Biomedical Applications

Natural and synthetic polymers have been explored for many years in the field of tissue engineering and regeneration. Researchers have developed many new strategies to design successful advanced polymeric biomaterials. In this review, we summarized the recent notable advancements in the preparation of smart polymeric biomaterials with self-healing and shape memory properties. We also discussed novel approaches used to develop different forms of polymeric biomaterials such as films, hydrogels and 3D printable biomaterials. In each part, the applications of the biomaterials in soft and hard tissue engineering with their in vitro and in vivo effects are underlined. The future direction of the polymeric biomaterials that could pave a path towards successful clinical implications is also underlined in this review.

Dissecting the Inorganic Nanoparticle-Driven Interferences on Adhesome Dynamics

Inorganic nanoparticles have emerged as an attractive theranostic tool applied to different pathologies such as cancer. However, the increment in inorganic nanoparticle application in biomedicine has prompted the scientific community to assess their potential toxicities, often preventing them from entering clinical settings. Cytoskeleton network and the related adhesomes nest are present in most cellular processes such as proliferation, migration, and cell death. The nanoparticle treatment can interfere with the cytoskeleton and adhesome dynamics, thus inflicting cellular damage. Therefore, it is crucial dissecting the molecular mechanisms involved in nanoparticle cytotoxicity. This review will briefly address the main characteristics of different adhesion structures and focus on the most relevant effects of inorganic nanoparticles with biomedical potential on cellular adhesome dynamics. Besides, the review put into perspective the use of inorganic nanoparticles for cytoskeleton targeting or study as a versatile tool. The dissection of the molecular mechanisms involved in the nanoparticle-driven interference of adhesome dynamics will facilitate the future development of nanotheranostics targeting cytoskeleton and adhesomes to tackle several diseases, such as cancer.

Prevent or Cure-The Unprecedented Need for Self-Reporting Materials

Self-reporting smart materials are highly relevant in modern soft matter materials science, as they allow for the autonomous detection of changes in synthetic polymers, materials, and composites. Despite critical advantages of such materials, for example, prolonged lifetime or prevention of disastrous material failures, they have gained much less attention than self-healing materials. However, as diagnosis is critical for any therapy, it is of the utmost importance to report the existence of system changes and their exact location to prevent them from spreading. Thus, we herein critically review the chemistry of self-reporting soft matter materials systems and highlight how current challenges and limitations may be overcome by successfully transferring self-reporting research concepts from the laboratory to the real world. Especially in the space of diagnostic self-reporting systems, the recent SARS-CoV-2 (COVID-19) pandemic indicates an urgent need for such concepts that may be able to detect the presence of viruses or bacteria on and within materials in a self-reporting fashion.

Biomedical Applications of Supramolecular Materials in the Controllable Delivery of Steroids

Glucocorticoids are a class of steroid hormones secreted from the adrenal glands. The strong anti-inflammatory effects make it be one of the most popular and versatile drugs available to treat chronic inflammatory diseases. Additionally, supramolecular materials have been widely exploited in drug delivery, due to their biocompatibility, tunability, and predictability. Thus, steroid-based supramolecular materials and the release of steroids have been applied in the treatment of inflammatory diseases. This mini-review summarized recent advances in supramolecular materials loaded with glucocorticoid drugs in terms of hydrophobic interactions, electrostatic interactions, hydrogen bonding, and π-π stackings. We also discussed and prospected the application of the glucocorticoid drugs-based supramolecular system on chronic rhinosinusitis, multifactorial inflammatory disease of the nasal and paranasal sinuses mucosal membranes. Overall, supramolecular materials can provide an alternative to traditional materials as a novel delivery platform in clinical practice.

Photoluminescent Nanoparticles for Chemical and Biological Analysis and Imaging

Research related to the development and application of luminescent nanoparticles (LNPs) for chemical and biological analysis and imaging is flourishing. Novel materials and new applications continue to be reported after two decades of research. This review provides a comprehensive and heuristic overview of this field. It is targeted to both newcomers and experts who are interested in a critical assessment of LNP materials, their properties, strengths and weaknesses, and prospective applications. Numerous LNP materials are cataloged by fundamental descriptions of their chemical identities and physical morphology, quantitative photoluminescence (PL) properties, PL mechanisms, and surface chemistry. These materials include various semiconductor quantum dots, carbon nanotubes, graphene derivatives, carbon dots, nanodiamonds, luminescent metal nanoclusters, lanthanide-doped upconversion nanoparticles and downshifting nanoparticles, triplet-triplet annihilation nanoparticles, persistent-luminescence nanoparticles, conjugated polymer nanoparticles and semiconducting polymer dots, multi-nanoparticle assemblies, and doped and labeled nanoparticles, including but not limited to those based on polymers and silica. As an exercise in the critical assessment of LNP properties, these materials are ranked by several application-related functional criteria. Additional sections highlight recent examples of advances in chemical and biological analysis, point-of-care diagnostics, and cellular, tissue, and in vivo imaging and theranostics. These examples are drawn from the recent literature and organized by both LNP material and the particular properties that are leveraged to an advantage. Finally, a perspective on what comes next for the field is offered.

Simultaneous surface functionalization and drug loading: A novel method for fabrication of cellulose nanocrystals-based pH responsive drug delivery system

Herein, a novel strategy for surface functionalization and drug loading of cellulose nanocrystals (CNCs) through formation of hydrazone bonds between functionalized CNCs and aldehyde group containing polyethylene glycol (CHO-PEG)/anticancer drug doxorubicin (DOX) was reported for the first time. DOX could be loaded on PEGylated CNCs with high capacity and released from drug complexes (P-CNCs-D) with pH dependent behavior. The biological evaluation results demonstrated that drug carriers (CNCs-EBO-NH) showed negative cytotoxicity while DOX could be transported into cells and exhibits desirable anticancer effects. As compared with other method, the method developed in this work is rather simple and effective and can be achieved for simultaneous for surface functionalization and drug loading in a one-pot route. This work will open a new avenue for fabrication of various multifunctional composites based on other carbohydrate polymers or materials and to explore their applications in biomedical fields.

Smart gating porous particles as new carriers for drug delivery

The design of smart drug delivery carriers has recently attracted great attention in the biomedical field. Smart carriers can specifically respond to physical and chemical changes in their environment, such as temperature, photoirradiation, ultrasound, magnetic field, pH, redox species, and biomolecules. This review summarizes recent advances in the integration of porous particles and stimuli-responsive gatekeepers for effective drug delivery. Their unique structural properties play an important role in facilitating the diffusion of drug molecules and cell attachment. Various techniques for fabricating porous materials, with their major advantages and limitations, are summarized. Smart gatekeepers provide advanced functions such as "open-close" switching by functionalized stimuli-responsive polymers on a particle's pores. These controlled delivery systems enable drugs to be targeted at specific rates, time programs, and sites of the human body. The gate structures, gating mechanisms, and controlled release mechanisms of each trigger are detailed. Current ongoing research and future trends in targeted drug delivery, tissue engineering, and regenerative medicine applications are highlighted.

Poly Lactic-Co-Glycolic Acid- (PLGA-) Loaded Nanoformulation of Cisplatin as a Therapeutic Approach for Breast Cancers

Despite recent advancements in cisplatin (cis-diamminedichloroplatinum II) and other platinum-based chemotherapeutic drugs for treating solid tumors, their uses are limited by either in terms of toxicity and/or acquired drug resistance. These side effects have a dangerous problem with higher dose for severe patients. To overcome the low therapeutic ratio of the free drug, a polymeric nanoparticle drug delivery system has been explored promoting delivery of cisplatin to tumors. Recently, the applications of nanoparticles (NPs) have been underlined for encouraging the effects of chemotherapeutic drugs in cancerous cells. The intention of this project is to assess the potential of poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) for enhancing the effects of anticancer drug cisplatin. For the purpose, we have synthesized PLGA-cisplatin nanoparticles for increasing its bioavailability and studied the comparative cytotoxicity of free cisplatin and PLGA-cisplatin against MCF-7 cancer cell lines and HEK-293 normal cell lines. We have also analyzed the hallmarks of PLGA-cisplatin-induced apoptosis. The outcomes of this study may provide the possibility of delivery of anticancer drug to their specific site, which could minimize toxicity and optimize the drug efficacy.

TMTP1-Modified, Tumor Microenvironment Responsive Nanoparticles Co-Deliver Cisplatin and Paclitaxel Prodrugs for Effective Cervical Cancer Therapy

Background and Purpose

Cisplatin-paclitaxel (TP) combination chemotherapy as the first-line therapy for numerous cancers is hindered by its inadequate accumulation in tumors and severe side effects resulting from non-specific distribution. The aim of this study is to explore whether TMTP1-modified, cisplatin and paclitaxel prodrugs co-loaded nanodrug could improve cervical cancer chemotherapy and relieve its side effects through active and passive tumor targeting accumulation and controlled drug release.

Methods

TDNP, with capacities of active targeting for tumors and controlled drug release, was prepared to co-deliver cisplatin and paclitaxel prodrugs. The characteristics were investigated, including the diameter, surface zeta potential, stability and tumor microenvironment (TME) dependent drug release profiles. Cellular uptake, cytotoxicity, drug accumulation in tumors, antitumor effects and safety analysis were evaluated in vitro and in vivo.

Results

The oxidized cisplatin and the paclitaxel linked to the polymer achieved a high loading effciency of over 80% and TME-dependent sustained drug release. Moreover, TMTP1 modification enhanced cellular uptake of TDNP and further improved the cytotoxicity of TDNP in vitro. In vivo, TDNP showed an extended blood circulation and increased accumulation in SiHa xenograft models with the aid of TMTP1. More importantly, TDNP controlled tumor growth without life-threatening side effects.

Conclusion

Our study provided a novel TP co-delivery platform for targeted chemotherapy of cervical cancer, which was promising to improve the therapeutic effcacy of TP and may also have application in other tumors.

Inflammatory microenvironment-targeted nanotherapies

Inflammatory microenvironments (IMEs) are common pathological characteristics and drive the development of multiple chronic diseases. Thus, IME-targeted therapies exhibit potential for the treatment of inflammatory diseases. Nanoplatforms have significant advantages in improving the efficiency of anti-inflammatory treatments. Owing to their improved therapeutic effects and reduced side effects, IME-targeted nanotherapies have recently drawn interest from the research community. This review introduces IMEs and discusses the application of IME-targeted nanotherapies for inflammatory diseases. The development of rational targeting strategies tailored to IMEs in damaged tissues can help promote therapies for chronic diseases.

The Use of Iron Oxide Nanoparticles to Reprogram Macrophage Responses and the Immunological Tumor Microenvironment

The synthesis and functionalization of iron oxide nanoparticles (IONPs) is versatile, which has enhanced the interest in studying them as theranostic agents over recent years. As IONPs begin to be used for different biomedical applications, it is important to know how they affect the immune system and its different cell types, especially their interaction with the macrophages that are involved in their clearance. How immune cells respond to therapeutic interventions can condition the systemic and local tissue response, and hence, the final therapeutic outcome. Thus, it is fundamental to understand the effects that IONPs have on the immune response, especially in cancer immunotherapy. The biological effects of IONPs may be the result of intrinsic features of their iron oxide core, inducing reactive oxygen species (ROS) and modulating intracellular redox and iron metabolism. Alternatively, their effects are driven by the nanoparticle coating, for example, through cell membrane receptor engagement. Indeed, exploiting these properties of IONPs could lead to the development of innovative therapies. In this review, after a presentation of the elements that make up the tumor immunological microenvironment, we will review and discuss what is currently known about the immunomodulatory mechanisms triggered by IONPs, mainly focusing on macrophage polarization and reprogramming. Consequently, we will discuss the implications of these findings in the context of plausible therapeutic scenarios for cancer immunotherapy.