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Conventional tumor-targeted drug delivery systems (DDSs) face challenges, such as unsatisfied systemic circulation, low targeting efficiency, poor tumoral penetration, and uncontrolled drug release. Recently, tumor cellular molecules-triggered DDSs have aroused great interests in addressing such dilemmas. With the introduction of several additional functionalities, the properties of these smart DDSs including size, surface charge and ligand exposure can response to different tumor microenvironments for a more efficient tumor targeting, and eventually achieve desired drug release for an optimized therapeutic efficiency. This review highlights the recent research progresses on smart tumor environment responsive drug delivery systems for targeted drug delivery. Dynamic targeting strategies and functional moieties sensitive to a variety of tumor cellular stimuli, including pH, glutathione, adenosine-triphosphate, reactive oxygen species, enzyme and inflammatory factors are summarized. Special emphasis of this review is placed on their responsive mechanisms, drug loading models, drawbacks and merits. Several typical multi-stimuli responsive DDSs are listed. And the main challenges and potential future development are discussed., Graphical abstract Image, graphical abstract

Stimulus responsive elastomers are advanced engineered materials that perform desired functionalities when triggered by external stimuli. Liquid crystal elastomers (LCEs) are one important example that exhibit reversible actuation when cycled above and below their nematic-to-isotropic transition temperature. Here, we propose a micromechanical-based model that is centered on the evolution of the chain distribution tensor of the LCE network. Our model, framed within the statistical model of the chain network, enables a mesoscale description of their mechanical response under an external thermal stimulus. We compare the model to prior experimental observations of the bending response of 3D printed LCE elements with controlled director alignment.

Stimuli-responsive polymers are materials that can display remarkable changes in their properties with slight change in environmental conditions. Substantial change in the structure and properties can be made to the textiles by the incorporation of smart polymers into them. The following characteristics for intelligent polymers viz., thermal-, moisture-, and light-responsive polymers, and thermal- and pH-responsive hydrogels, have been incorporated into the fabrics to improve or achieve smart fabric functionalities. The functional components include esthetic appeal, comfort, drug release, fantasy design (color changing), wound monitoring, smart wetting properties, and protection against tough environmental alterations. In this chapter, the applications of stimuli-responsive polymer/composites in fabrics and the clothing field have been deliberated upon; the related issues on the fabrication of clothing and their potential applications in the years to come are elucidated.

Nanotheranostic platform has been proposing innovative strategies in the field of nanotechnology for the diagnosis and treatment of several types of cancer. Among the metal nanocarriers, gold nanoparticles (AuNPs) have focused attractive attention in cancer theranostics owing to their distinctive physicochemical properties such as large surface area to volume ratio, surface plasmon resonance, surface chemistry with multifunctionalization ability and stability. This chapter highlights the physiology of tumor and tumor microenvironment, nanotheranostics, and several types of gold nanosystems developed as nanotheranostics. A special emphasis has been given on the effect of various stimuli such as internal stimuli (pH, enzymes, and glutathione) and external stimuli (temperature, laser, and ultrasound) on AuNPs for diagnosis and treatment of cancer. Some latest promising developments with their functionalization, in vitro and in vivo effects of stimuli-responsive AuNPs are also discussed.

The understanding of progressive advances in the development of intelligent systems based on biocompatible, biodegradable, and renewable resources and their applications in important fields, such as medical, pharmaceutical, agricultural, and industrial, have increased attention in the use of cellulose for obtaining stimuli-responsive materials. Within the smart polymer systems, one of the most relevant is hydrogels, which are materials with important characteristics of water absorption, elasticity, and multifunctionality. These materials have been developed from several renewable sources such as chitin, starch, and cellulose; in particular, cellulose and cellulose by-products have allowed the designing of hydrogels with a wide range of functionalities and applications. Of interest for us, hydrogels are capable of experiencing a response as a result of changes in their environment or external stimuli, which can be chemical or/and physical, for example, pH, temperature, ionic strength, and electromagnetic fields, among others. Initially, in this chapter, physical-chemical properties and the importance of cellulose as a polymeric material will be described, emphasizing its use for obtaining stimuli-responsive hydrogels and their applications, in particular, in the biomedical field. In this way, their properties, the obtaining routes, and characterization methods of stimuli-responsive cellulose-based hydrogels (CBHG), from physical to chemical, are analyzed and described. Finally, significant applications of stimuli-responsive, CBHGs in drug-controlled release and tissue engineering are shown and discussed.

This century has witnessed a revolution in nanodrug delivery systems to meet the increasing demands of managing chronic inflammatory diseases. As nanodrug delivery poses certain limitations in the form of uncontrolled drug release, drug leakages, and nonspecific biodistribution, smart drug delivery systems have come into focus to address these issues for delivering the drug in controlled and timely manner at precise location. This chapter focuses on the various smart drug delivery systems that are stimuli responsive such as redox, enzyme pH, temperature, and magnet and responsive drug delivery systems that are promising in delivering natural drugs that help to cure numerous inflammatory diseases.

Stimuli-responsive nanofibrous materials have attracted considerable attention as smart versatile tools that show various potential in the biomedical field. In this chapter, an overview is given of recent developments of nanofiber-based drug delivery systems. The characteristics of stimuli-responsive electrospun nanofibers with different triggered-release mechanism are discussed, and the advantages of these advanced stimuli-responsive polymeric systems are highlighted. Hence, several emerging internal and external stimuli including pH, temperature, light, and electric/magnetic field are considered to realize more advanced control and manipulation of precise and efficient release of therapeutic materials through nanofibrous structures. In brief, it can be stated that the stimuli-responsive nanofibrous materials are promising candidate to mimic the living systems with both functions of the fibrous structural feature and bio-regulation function as an on demand drug release carrier.

Our contribution to mesoporous silica materials in the field of biomedicine are reported in this article. This perspective article represents our work in the basics of the material, preparingdifferent ranges of mesoporous silica nanoparticles with different diameters and with varied pore sizes. We demonstrated the high loading capacity of these materials. Additionally, the possibility of functionalizing both internal and external surface with different organic or inorganic moieties allowed the development of stimuli-responsive features which allowed a proper control on the administered dose. In addition, we have demonstrated that these carriers are not toxic, and we have also ensured that the load reaches its destination without affecting healthy tissues. Statement of Significance: Advances on mesoporous silica materials in the field of biomedicine are herein reported. This perspective article represents our work on the fundametals of the material, preparing different ranges of mesoporous silica nanoparticles with different diameters and with varied pore sizes. The high drug loading capacity of these materials is demonstrated. Moreover, the possibility of functionalizing both internal and external surface with different organic or inorganic moieties allowed the development of stimuli-responsive nanocarriers which allowed a proper control on the administered dose. In addition, we have demonstrated that these carriers are not toxic, and we have also ensured that the load reaches its target without affecting healthy tissues.

Drug delivery systems are greatly used in biomedical applications due to their distinctive therapeutic advantages such as controlled drug release over prolonged time intervals, protection from early drug degradation, and reductions in drug toxicity and drug-drug interactions. Tuberculosis is a highly contagious disease spread by Mycobacterium tuberculosis. Nanoparticle-based drug delivery platforms have obtained significance for use through the pulmonary route. A variety of nanocarrier systems have been developed to optimize the delivery of antituberculosis drugs. The nanocarriers introduced enhance the bioavailability and targeting efficiency of loaded nanocarriers into the affected areas. Such nanocarriers are generally developed with stimuli-responsive materials that can be triggered with internal and external stimuli such as pH, temperature, magnetic fields, light, or hypoxia. They can be further induced by assured biological changes such as enzyme hydrolysis and molecular conformational changes, which lead to the controlled release of drugs into the target sites. In this chapter, we discuss the various stimuli-responsive nanotherapy drug delivery systems and current strategies for antituberculosis treatment.

As science progresses, human beings have gone to the production and use of smart technologies. Smart drug release systems have recently become an exciting field. In this context, responsive polymers are integral parts. Stimuli-sensitive or intelligent polymers undergo an abrupt change in their physical properties in response to a small external or internal environmental stimulus. Temperature, pH, light, electric or magnetic, and biostimulants are the driving forces for controlling drug release. Therefore understanding the structures of these stimuli-responsive polymers is a crucial point for smart drug release systems. This chapter serves as a bridge between polymer science and drug release knowledge.

Stimuli-responsive materials, frequently designated as “smart/intelligent materials”, can modify their structure or properties by either a biological, physical, or chemical stimulus which, if properly controlled, could be used for specific applications. Such materials have been studied and exploited in several fields, like electronics, photonics, controlled drugs administration, imaging and medical diagnosis, among others, as well as in Analytical Chemistry where they have been used as chromatographic stationary phases, as part of sensors and for extraction purposes. This review article pretends to provide an overview of the most recent applications of these materials (mostly polymeric materials) in sample preparation for extraction purposes, as well as to provide a general vision of the current state-of-the-art of this field, their potential use and future applications., J.G.S. would like to thank “Cabildo de Tenerife” for the Agustín de Betancourt contract at the Universidad de La Laguna. The support of the Spanish Ministry of Science and Innovation (project PGC2018-094503-B-C21) is granted. This article is also based upon work from the Sample Preparation Task Force and Network supported by the Division of Analytical Chemistry of the European Chemical Society.

The rapid development of nanotechnology results in the emergence of nanomedicines, but the effective delivery of drugs to tumor sites remains a great challenge. Prodrug-based cancer nanomedicines thus emerged due to their unique advantages, including high drug load efficiency, reduced side effects, efficient targeting, and real-time controllability. A distinctive characteristic of prodrug-based nanomedicines is that they need to be activated by a stimulus or multi-stimulus to produce an anti-tumor effect. A better understanding of various responsive approaches could allow researchers to perceive the mechanism of prodrug-based nanomedicines effectively and further optimize their design strategy. In this review, we highlight the stimuli-responsive pathway of prodrug-based nanomedicines and their anticancer applications. Furthermore, various types of prodrug-based nanomedicines, recent progress and prospects of stimuli-responsive prodrug-based nanomedicines and patient data in the clinical application are also summarized. Additionally, the current development and future challenges of prodrug-based nanomedicines are discussed. We expect that this review will be valuable for readers to gain a deeper understanding of the structure and development of prodrug-based cancer nanomedicines to design rational and effective drugs for clinical use.

“Smart” stimuli-responsive materials have been the subject of decades of research because of their versatility and particularly their use in medical and sensing applications. While these materials are often composed exclusively of responsive polymers, there is growing interest in smart hybrid systems that contain at least two distinct components, each contributing uniquely to the final material. Cellulose nanocrystals (CNCs) have found extensive application in smart hybrid systems, as CNCs can both contribute to the mechanical and optical properties of the system and bear stimuli-responsive surface modifications. This review covers the recent body of work on CNC-containing smart hybrid systems, with attention given to the fabrication methodologies that have been employed to generate both physically and optically adaptable CNC-based smart systems. Additionally, the unique application of CNCs in self-healing composites and shape memory polymers will be discussed. Keywords: Sustainable nanomaterials, Smart materials, Polymers, Hybrid systems

This chapter highlights the new strategies in application of polyelectrolyte multilayers for delivery of drugs and bioactives with focus on the biocompatible and biodegradable components. Further, it incorporates extensive information on recent achievements in encapsulation of bioactives and drugs into multilayers, their structure as well as the driving forces and the mechanisms of stimuli responsive films and capsules. The case studies are discussed for (1) formation of multilayers for polynucleotides and proteins protection and delivery; (2) hydrogels as promising carriers for drug delivery, (3) decoration of surfaces of implants, and (4) target delivery of cells, genes, proteins, etc. using functional multilayered systems. PE multilayers have elaborative applications in regenerative medicine, anticancer therapy, bionic devices, and biosensing.

Natural polymer-based stimuli-responsive hydrogels change properties according to the external environment. The fundamental understanding of the mechanisms of responsiveness and the effects of natural polymers in chemical stimulations, physical stimulations, biostimulations are important. In this chapter, the advancements of stimuli-responsive natural polymer-based hydrogels in recent years will be discussed.

Silk-based natural polymeric materials widely known for its mechanical strength, biocompatibility, and biodegaradability have now shown wide potential as a class of smart materials. These materials are capable to respond to peripheral stimuli such as pH, salt, temperature, magnetic or electric, optical field, etc. Smart polymer materials have huge potentials for drug delivery system, gene carrier, tissue engineering, protein purification, dentistry, cosmetics, bioimaging, sensing, etc. This chapter inclusively summarizes the content of this book, which tries to provide overview of smart polymers. We review the different types of smart polymers and describe reported silk-based biopolymers that are extensively studied for stimuli responsive system. Finally, we conclude the current state of and expected outcomes of the smart materials in medical application.

Conventional chemotherapeutic drugs cause severe adverse effects during clinical uses. A compact delivery vehicle triggered to release its payload in the tumor microvasculature without affecting healthy tissues which could be a very likely to improve the therapeutic window of any anticancer drug. Sugar-based hydrogels possess an inherent ability to respond toward environmental stimuli. These types of bioinspired hydrogels are capable of mimicking the native tumor microenvironment by generating three-dimensional tumor models which are emerging hotspots in modern cancer research. Therefore, they have very promising applications both for fundamental cancer research as in vitro tumor model and for anticancer drug screening. This chapter is specifically themed to give a glimpse of the different approaches developed using hydrogels to study various aspects of cancer biology. The primary aim is to motivate researchers toward the design and synthesis of novel stimuli-responsive sugar-derived bioinspired hydrogels for making next-generation smart materials.

Stimuli-responsive drug delivery nanosystems have received great attention recently, due to their significant advantages, such as their ability for targeted content release, by responding to the altered conditions of the pathological tissues, such as temperature and pH. Toward the development of new and more effective stimuli-responsive nanosystems for biomedical applications, a great variety of different smart stimuli-responsive polymers has been exploited. The combination of different in nature biomaterials, such as lipids and stimuli-responsive polymers, can provide chimeric/mixed advanced drug delivery liposomal nanosystems and also stabilize other nonlamellar lyotropic lipidic liquid crystalline nanosystems with upgraded functionality. In this chapter, the two abovementioned categories of stimuli-responsive lipidic nanocarriers are examined through different literature examples, also highlighting useful characterization techniques that should be applied toward the rational development and evaluation of this highly promising class of nanosystems.

Recent years, carbon nanotubes (CNTs) have drawn much interest by the scientists and researchers worldwide on account of their small dimensional and unique architectural structures. CNTs rolled up seamless cylinders of graphene sheets exhibiting improved chemical, physical, as well as mechanical features, which render these with enormous potential in a variety of biomedical fields, particularly in the nano-drug delivery and drug targeting applications. On the basis of graphene layer numbers, a single nanotube is composed. CNTs are classified as single-walled, double-walled, and multiple-walled nanotubes. This chapter deals an overview of types, production methods, and functionalization approaches of CNTs, which are being utilized in order to render CNTs more useful the domain of drug delivery and drug targeting applications. Besides providing a bird’s eye views on the drug delivery by using CNTs, this chapter also presents a thoughtful insight with regulatory concerns, which is required to be addressed before the CNTs-based drug delivery and drug targeting systems are actually launched in the market. Amongst all the preferable properties, the CNTs must be customized with elegant polymers before use in controllable delivery of drug. To develop stimuli-responsive delivery of drug, much effort has been made, from which the release of drug is made under particular stimuli response.

Advances in polymer science have enabled to mimic the response of living system to external stimuli by developing a group of polymers that can undergo reversible large, significant physiochemical changes in response to small external changes in the environmental conditions, such as pH, temperature, light, ionic factors, magnetic or electric field, biological molecules, etc. Challenges confronted by oral insulin delivery now-a-days, demand sensitive efficient systems for successful oral delivery with improved oral insulin bioavailability not compromising with the safety and hypoglycemic episodes. The “stimuli responsive” or “smart” polymers have gained considerable attention in the regard because their changes are reversible; they are capable of releasing entrapped insulin at the appropriate time and site of action in response to specific physiological triggers. Moreover, these polymers exhibit a nonlinear response to a small stimulus owing to macroscopic alteration in their structural properties. Their responses also vary widely from swelling contraction to disintegration. Synthesis and application of stimuli- responsive polymers with better biodegradability and greater biocompatibility would enhance the efficacy of oral insulin delivery. The most fascinating features of the stimuli-responsive polymers arise from the versatility and their tunable sensitivity. However, slow response time can be a significant weakness of stimuli-sensitive polymers. Therefore, combinatorial synthesis can help in tuning the polymer sensitivity to a given stimulus within a narrow range. In this chapter, we will highlight various applications and the mechanism of action of stimuli-responsive polymers in advanced oral insulin delivery.

Diabetes mellitus is reported as one of the most severe and lethal diseases in the world, formed by the accumulation of glucose in the blood and the number of diabetic patients will be going to cross ~ 552 million by 2030. However, after so many innovations and discoveries, insulin is the only drug used to maintain blood glucose levels and gives prolong lives to the diabetic patients. The traditional administration of insulin was based on frequent subcutaneous insulin injections which have certain side effects like pain, infection, local tissue necrosis, and nerve damage. Therefore, the fabrication of self-regulated insulin delivery systems which can automatically regulate the amount of insulin released according to the change of blood glucose level is in high demand. On this context, stimuli-responsive systems have gained attention of researchers due to their less side effects and improved efficacy. Stimuli-responsive polymers have the ability to respond to a certain external environmental changes (termed as “stimulus”) by altering some of their physical and chemical properties. For insulin delivery, the majority of the stimuli- responsive system lies on the change in pH and/or glucose concentration; however, recently, some of the temperature, electrochemical, and redox-responsive polymeric systems were reported. These systems show rapid change in their structure and/or respond with respect to the variation in pH, temperature, glucose concentration, etc., so that rapid release of insulin can take place. This chapter is an effort to combine the past, present, and future of the stimuli-responsive polymer-based drug delivery system for treatment of diabetes mellitus in a simplest way.

Responding to a stimulus is a natural phenomenon within living systems as most biomolecules are able to change their structures and one or more of their properties in response to external stimuli. Nature serves as the model for stimuli-responsive materials but it still a challenge to create new nanosized supramolecules that can sense various external physical and chemical stimuli. This chapter concentrate on recent developments and new exciting approaches to create nanosized supramolecular gold(I) complexes capable of sensing mechanical, thermal, light, and chemical stimuli. Gold(I) centers are particularly versatile as the component of such systems based on their high tendency to form aurophilic Au ··· Au interaction that can be highly sensitive to external stimuli. The role of weak and flexible noncovalent interactions, including metal-ligand, metal-metal, hydrogen bonding, π ··· π stacking, and metal-solvent in triggering the stimuli-responsive behavior of solid-state materials is presented. Stimuli-responsive self-assembled materials based on gold(I) that are sensitive to various physical and chemical stimuli and show reversible structural transformations as well as visual color or emission color changes is the main focus of the chapter. Exciting multistimuli-responsive photoluminescence of some self-assembled structures and aggregation-induced emission (AIE) of nanoaggregates are also discussed. Such stimuli-responsive functional materials with switchable photoluminescence properties attract considerable attention for a variety of applications, including optical storage and memories, optoelectronic and display devices, and mechanical and chemical sensors.

Carbohydrates are ubiquitous in nature and intervene in a wide range of biological activities. They exhibit interesting properties such as low toxicity, biocompatibility, stability, low cost, hydrophilic nature, and availability of reactive sites for chemical modification. During the last decade, there have been many attempts to integrate carbohydrates in nanomaterials. In particular, smart glycopolymers have received remarkable attention due to their responsiveness to specific stimuli, making them promising candidates for more accurate and programmable drug delivery. Carbohydrate-based nanoparticles with pH, enzyme, magnetic, redox, and temperature-sensitive properties have been developed. In addition, sugar-based nanogels have also emerged as potential nanocarriers. Under this light, the state-of-the-art of stimuli-responsive glyconanoparticles will be covered. We highlight the design of tunable and versatile carbohydrate-based nanoparticles as targeted carriers with stimuli-triggered controlled and localized drug release. We hope this will stimulate the development of novel glyconanomedicines that are easier to handle, compatible with physiological media, and suitable for further clinical developments.

The introduction of stimuli-responsiveness in therapeutic systems facilitates/tunable release of the therapeutic(s) at the target site, improving their bioavailability and reducing the off target toxicity. The functionality of such drug delivery systems can further be enhanced by the incorporation of an imaging modality. This allows precise spatiotemporal focusing of the trigger as well as real-time imaging and control of the dose, while tracking the response to the therapy. This chapter discusses the emerging trends in different stimuli-responsive smart polymers with image-guidance capability along with their therapeutic applications and clinical prospects.

There is a considerable research interest in polymers for drug delivery systems in the medical and pharmaceutical field. Several polymeric materials have been investigated in the development of nanostructures for drug delivery to increase therapeutic advantages while minimizing side effects. The cutting-edge and emerging research focuses involve the design and development of stimuli-responsive materials. In particular, polymersomes are artificial polymeric vesicles that have received significant attention due to their entangled architecture. Smart polymersomes can recognize some environmental stimuli and release the drug loaded in dose-, spatial-, and temporal-controlled manners. This chapter aims to cover the recent advances in biological-stimuli-responsive and external-stimuli-responsive polymersomes. Aspects related to the mechanism involved in the drug release and some examples of their main biomedical applications will be highlighted. Also, the use of stimuli-responsive polymersomes for cancer therapy will be stressed.

Environment-responsive drug delivery systems have emerged as attractive alternative to traditional systems, delivering therapeutic agents on-demand to their target tissue. Temperature and pH arise as two of the most commonly utilized stimuli for triggering these responses. Among polymeric carriers, temperature and pH dual-responsive nanocarriers were developed to exhibit changes in drug-release rate or particle size upon change in environment’s pH and temperature. In this chapter, various design aspects of temperature- and pH-dual-responsive polymeric nanocarriers are discussed in details with examples, illustrating different responsive polymeric materials used in their fabrication. The interplay between temperature and pH responsiveness within the polymeric nanocarriers is discussed too.

Stimuli-responsive polymers are the type of polymeric materials defined as the responsive materials with the ability to react, sense, and respond to external condition in a predetermined shape. When stimuli-responsive polymers laminated/coated to a fabric, a smart fabric (waterproof, windproof, and breathable) is formed. It is also possible to coat polymeric materials on a fabric such that its permeability changes as the wearer’s environment and body (skin) temperature change to form an ideal combination of thermal insulation and vapor permeability for clothing. After forming the functional fabric, the laminated/coated textiles will be able to sense the temperature and humidity. When the temperature is low, the textiles will be less permeable and keeps the body warm but when the temperature is high and body is in a sweat condition, it will allow the water molecule to pass through because its moisture permeability becomes very high with increased temperature. Stimuli-responsive textiles have many applications like thermal protective clothing, sportswear, shape memory fibers, smart fabric, packaging, transportation, and other uses.

This chapter discusses the state of the art of stimuli-responsive nanomaterials including nanocomposites, metallic nanomaterials, sensors, biosensors, nanomedicine, and mesoporous materials with potential biomedical applications and focuses on the interest of nanomaterials. Nanomaterials are multifunctional due to the incorporation of both therapeutic and bioimaging agents. The different types of nanomaterials are fabricated using several approaches ranging from conventional chemical methods to more sophisticated processes such as surface modification by synthesis of inorganic and organic nanomaterials to obtain layers free of pollutant without purification and isolation processes, among other advantages for obtaining new materials of special physical-chemical properties.

In this chapter, stimuli responsive or “smart” nanosystems with applications in the pharmaceutical and biomedical fields are described. Responsive polymeric nanotherapeutics are capable of performing interesting functions in response to an appropriate stimulus, whether internal or external such as pH, temperature, ultrasound, light, magnetic, radiation, redox, or biological stimuli as enzymes, reactive oxygen species, adenosine triphosphate, glutathione, glucose, and dual-responsive stimuli are described. Such kinds of nanosystems open new possibilities for therapy of many diseases with special reference to cancer.

Ocular drug delivery (ODD) imposes challenges to the formulation scientist because of physiological constraints. The use of stimuli-responsive polymers in ophthalmic formulations results in increase in absorption of drug as well as residence time. In recent years, pharmaceutical formulations based on stimuli-responsive polymers have gained increasing interest especially in the fields of targeted and controlled drug delivery systems. Stimuli-sensitive polymers such as thermo-responsive, pH-sensitive, ion-sensitive, or dual-responsive polymers are utilized in ODD systems. This chapter focuses on the recent developments, current applications, and future trends dealing with stimuli-responsive polymers in the field of ODD. This chapter also outlines various ophthalmic formulations based on stimuli-responsive polymers.

Recent advancements in membrane technology have led to the creation of responsive materials in which the interfacial properties can be controlled by external stimuli. This has made the development of switchable molecular sieving responsive membranes with a self-cleaning capability possible. This chapter is dedicated to summarizing the progress of stimuli responsive membranes with reversibly switchable physicochemical properties. Here, the implementation of stimuli responsive membranes in water treatment is introduced. Structural flexibility of stimuli responsive materials is discussed to initiate the requirements of stimuli membranes. Next, types of stimuli responsive membranes and their applications as separation tools for controllable physicochemical changes in response to environmental cues are reviewed. Topics on synthesis and modification of stimuli responsive membranes are also introduced and discussed. Finally, the feasibility of implementing stimuli responsive membranes for industrial processes is highlighted.

If we define the smartness of a material as the capacity of that material to significantly change some of its properties in a controlled way as response to an external stimuli, such as temperature, pH, light, electric or magnetic fields, not many materials can be considered as smart material and only a few proteins fit in this classification. In this chapter, we not only will explore these smart proteins but the capacity to be processed as fibers. We will explore the possibilities that peptide-based fibrous systems, silk-based fibers, and elastin-based materials offers to be processed as fibers that heritage their smart properties. We will travel across the applications in which these fibers are being tested or applied.

The formation of ordered nanostructures within the gel phase from colloidal systems can be driven by different types of external stimuli such as temperature, light, ultrasound, electric and magnetic fields, and through the processes of transformation, diffusion, and chemical sensitivity. This chapter illustrates some gains from this area of research and presents building blocks of enormous potential for the development of intelligent materials based on molecules that will bring improvements and improvements to systems based on nanotechnology.

Stimulus-responsive micelles are considered important because of their capability to change their properties rapidly in response to the environment. The functions and properties of such micelles can be modified by a slight adjustment in pH, temperature, light, redox environment, and so forth. These micelles can also respond to biological stimuli and are used as “smart” nanocarriers for imaging agents or anticancer therapeutics for cancer diagnosis and therapy. The applications of micelles as nanocarriers are extensively explored due to their exceptional biocompatible and physicochemical properties, friendly preparation methods, excellent drug-loading and release capabilities, and cancer targetability. They can be easily integrated with various moieties to introduce versatile functionalities for further improvement in their role in terms of circulation time, bioavailability, tumor targeting, and anticancer efficiency. Moreover, multiresponsive micelles are promising material for drug delivery due to their ability to tune via several mechanisms. Here, we discuss the recent development in responsive micelles, especially their ability to increase bioavailability, targeted drug delivery, and drug-loading and release capacities.

Nano drug delivery system is a well-defined strategy for cancer therapy. The basic features of delivery system are the encapsulation of insoluble chemotherapeutic cargo, increased circulation time in body, and reasonable accumulation of drug at the target site. Recently stimuli-responsive nano drug delivery systems have gained popularity due to the additional feature of controlling drug release on command (external) or based on cancer environment (internal). In this chapter, we have provided an overview of various kinds of external (photothermal, photodynamic, magnetic, and ultrasound) and internal (pH, Redox, Enzyme, ROS) stimuli-responsive nanoparticle drug delivery systems and future perspective.

The development of stimuli-responsive nanomedicines with tunable cargo release is gathering an increased applicability in bone regeneration and precision biomedicine. Yet, the formulation of nanocarriers that explore skeletal-specific stimuli remains remarkably challenging to materialize due to several endogenous and disease-specific barriers that must be considered during particle design stages. Such anatomo-physiological constrains ultimately hinder nanocarriers bioavailability in target bone tissues and impact the overall therapeutic outcome. This review aims to showcase and critically discuss the hurdles encountered upon responsive nanocarriers delivery in the context of skeletal diseases or tissue regeneration scenarios. Such focus is complemented with an in-depth and up-to-date analysis of advances in the development of stimuli-responsive, bone-focused delivery systems. In a holistic perspective, a deeper knowledge of human osteology combined with advances in materials functionalization via simple precision-chemistry is envisioned to incite the manufacture of stimuli-triggered nanomedicines with more realistic potential for clinical translation. published