External Environmental Stimuli Research Articles

Poly(N‐isopropylacrylamide) and Its Copolymers: A Review on Recent Advances in the Areas of Sensing and Biosensing

AbstractStimuli‐responsive polymers have received increasing attention for various applications due to their ability to adapt physical and chemical properties in response to external environmental stimuli. In this regard, poly(N‐isopropylacrylamide) (PNIPAM) is the most extensively studied stimuli‐responsive polymer and, consequently has been prominently featured in (bio)‐sensor development, adaptive coating technology, drug delivery, wound healing, tissue regeneration, artificial actuator design, sensor technology, responsive coatings, and soft robotics. This success can be mainly attributed to the accessible and versatile nature of the PNIPAM platform, thus allowing the synthesis of a wide variety of copolymer architectures, topologies and compositions. Within this review, the structural and compositional features of PNIPAM‐based materials in sensor and biosensor applications are discussed with a focus on the literature from 2016 until now. The reader is provided with the current state of the art regarding PNIPAM‐based sensor development and their molecular design. Finally, the challenges ahead in the successful implementation of PNIPAM‐based sensors are highlighted, as well as the opportunities in the rational design of improved PNIPAM‐based sensors. Altogether, this review provides comprehensive insights into the exciting and rapidly expanding field of PNIPAM‐based sensing systems, which will benefit the chemical, pharmaceutical, textile, and biotech industries is believed.

How Essential Oils Affect Children with Congenital Zika Virus Syndrome (CZVS)

Introduction: Within the field of dentistry, essential oils are well-known and extensively researched; eugenol is one of the most used, which until recently characterized the predominant smell of dental offices. Children with congenital Zika virus syndrome (CZVS) have various impairments, and in the dental area, the vast majority exhibit underdevelopment of the stomatognathic system compared to established normality standards. Many use various medications, such as anticonvulsants, muscle relaxants, sedatives, neuroleptics, among others, to control symptoms. These drug interactions can trigger involuntary muscle movements, including bruxism. There are several treatment proposals for teeth grinding and clenching, including appliance therapy, emotional therapies, medication, and also aromatherapy. Material and method: Syndromic and bruxist children were selected through validated questionnaires and clinical examination. A convenience sample of 19 syndromic children from Maceió was divided into two random groups: group 1 received a blend of essential oils, and group 2 received a control oil. They were instructed to apply it topically to the masseter, temples, and cervical area twice a day for two months. Sleep analysis was carried out through a questionnaire with 15 questions plus filling out a sleep chart for three days and collecting saliva in Salivette tubes for cortisol evaluation, with both data sets collected pre and post-use of essential oils. Discussion: Previous studies report that individuals with cognitive difficulties are more prone to bruxism due to spasticity, however, they are not definitive according to other studies. There are other factors such as stress, depression, external environmental stimuli that can influence this condition, in addition to the drug interaction they use to alleviate symptoms such as seizures, drooling, muscle spasms, muscle stiffness, insomnia. The etiology of bruxism is still considered multifactorial, requiring a multidisciplinary clinical team for more effective treatment. The use of essential oils as a stress and insomnia reliever is reported in studies with satisfactory results, being observed in this research. Result: In the finalization phase. Conclusion: Given the above, the proposal was to evaluate the efficacy of using essential oils in syndromic and bruxist children. Although we cannot confirm results yet, there are reports from mothers who evaluated the initiative positively, corroborating in some way the alleviation of symptoms and drug interactions, providing more emotional and physical comfort for those involved. However, more clinical trials are still necessary regarding the safety and efficacy aspects of essential oils.

Research Progress in Skin Aging and Immunity.

Skin aging is a complex process involving structural and functional changes and is characterized by a decrease in collagen content, reduced skin thickness, dryness, and the formation of wrinkles. This process is underpinned by multiple mechanisms including the free radical theory, inflammation theory, photoaging theory, and metabolic theory. The skin immune system, an indispensable part of the body's defense mechanism, comprises macrophages, lymphocytes, dendritic cells, and mast cells. These cells play a pivotal role in maintaining skin homeostasis and responding to injury or infection. As age advances, along with various internal and external environmental stimuli, skin immune cells may undergo senescence or accelerated aging, characterized by reduced cell division capability, increased mortality, changes in gene expression patterns and signaling pathways, and altered immune cell functions. These changes collectively impact the overall function of the immune system. This review summarizes the relationship between skin aging and immunity and explores the characteristics of skin aging, the composition and function of the skin immune system, the aging of immune cells, and the effects of these cells on immune function and skin aging. Immune dysfunction plays a significant role in skin aging, suggesting that immunoregulation may become one of the important strategies for the prevention and treatment of skin aging.

Present and Future Use of Exosomes in Dermatology

Abstract Exposure to external environmental stimuli can lead to skin aging, pigmentation, hair loss, and various immune-mediated as well as connective tissue diseases. Although conventional treatments are routinely used and favoured, they fail to achieve an adequate balance between clinical and cosmetic outcomes. Exosomes are vesicles with a lipid bilayer released by several cell types. These bioactive vesicles play a crucial role in intercellular communication and in several other physiological and pathological processes. They serve as vehicles for bioactive substances including lipids, nucleic acids, and proteins, making them appealing as cell-free treatments. According to studies, exosomes play a vital role in preventing scarring, and senescence, and promoting wound healing. Moreover, research on the biology of exosomes is growing, which has enabled the creation of specific guidelines and quality control methodologies to support their potential implementation in the future. In this review, we have mainly focused on the role of exosomes in various dermatological diseases, their clinical applications, and the potential for further research pertaining to this.

β-sheets mediate the conformational change and allosteric signal transmission between the AsLOV2 termini.

Avena sativa phototropin 1 light-oxygen-voltage 2 domain (AsLOV2) is a model protein of Per-Arnt-Sim (PAS) superfamily, characterized by conformational changes in response to external environmental stimuli. This conformational change begins with the unfolding of the N-terminal A'α helix in the dark state followed by the unfolding of the C-terminal Jα helix. The light state is characterized by the unfolded termini and the subsequent modifications in hydrogen bond patterns. In this photoreceptor, β-sheets are identified as crucial components for mediating allosteric signal transmission between the two termini. Through combined experimental and computational investigations, the Hβ and Iβ strands are recognized as the most critical and influential β-sheets in AsLOV2's allosteric mechanism. To elucidate the role of these β-sheets, we introduced 13 distinct mutations (F490L, N492A, L493A, F494L, H495L, L496F, Q497A, R500A, F509L, Q513A, L514A, D515V, and T517V) and conducted comprehensive molecular dynamics simulations. In-depth hydrogen bond analyses emphasized the role of two hydrogen bonds, Asn482-Leu453 and Gln479-Val520, in the observed distinct behaviors of L493A, L496F, Q497A, and D515V mutants. This illustrates the role of β-sheets in the transmission of the allosteric signal upon the photoactivation of the light state.

Hexosamine biosynthesis and related pathways, protein N-glycosylation and O-GlcNAcylation: their interconnection and role in plants.

N-Acetylglucosamine (GlcNAc), a fundamental amino sugar moiety, is essential for protein glycosylation, glycolipid, GPI-anchor protein, and cell wall components. Uridine diphosphate-GlcNAc (UDP-GlcNAc), an active form of GlcNAc, is synthesized through the hexosamine biosynthesis pathway (HBP). Although HBP is highly conserved across organisms, the enzymes involved perform subtly distinct functions among microbes, mammals, and plants. A complete block of HBP normally causes lethality in any life form, reflecting the pivotal role of HBP in the normal growth and development of organisms. Although HBP is mainly composed of four biochemical reactions, HBP is exquisitely regulated to maintain the homeostasis of UDP-GlcNAc content. As HBP utilizes substrates including fructose-6-P, glutamine, acetyl-CoA, and UTP, endogenous nutrient/energy metabolites may be integrated to better suit internal growth and development, and external environmental stimuli. Although the genes encoding HBP enzymes are well characterized in microbes and mammals, they were less understood in higher plants in the past. As the HBP-related genes/enzymes have largely been characterized in higher plants in recent years, in this review we update the latest advances in the functions of the HBP-related genes in higher plants. In addition, HBP's salvage pathway and GlcNAc-mediated two major co- or post-translational modifications, N-glycosylation and O-GlcNAcylation, are also included in this review. Further knowledge on the function of HBP and its product conjugates, and the mechanisms underlying their response to deleterious environments might provide an alternative strategy for agricultural biofortification in the future.

Virtual reality and tourism destinations marketing: can it transform travel? evaluating the impact of immersive experiences on travel intentions

ABSTRACT This study investigates the relationship between the immersive VR experience, destination cognitive image, destination affective image, and tourists’ travel intention. The sample of this research is 167 visitors of three tourist attractions of Isfahan Province in Iran, through 360-degree virtual reality videos. In order to collect research data, an online survey and convenience sampling methods were used. PLS-SEM was utilised to assess both the measurement and structural models. The findings indicated that among factors of external technical environment stimuli, media richness has a stronger effect on the formation of the destination's cognitive image than the affective image. Also, perceived interactivity compared to media richness has a significant impact on the formation of the destination's affective image. In addition, vision consistency as an internal technical environment stimulus has a positive effect on the formation of the cognitive and affective image of the destination. Finally, the affective image of the destination resulting from the immersive VR experience has a stronger effect on travel intention than the cognitive image.

Chronic restraint stress induces abnormal behaviors in pain sensitivity and cognitive function in mice: the role of Keap1/Nrf2 pathway

Stress is a series of physical and psychological responses to external and internal environmental stimuli. Growing studies have demonstrated the detrimental impacts of acute restraint stress (ARS) and chronic restraint stress (CRS) on animal behavior. However, the related pathogenesis and therapeutic mechanisms remain unclear. Hence, the present study aimed to examine whether unfolded protein response (UPR) and Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 related factor 2 (Nrf2) pathway are associated with ARS- and CRS- induced abnormal behaviors of pain sensitivity and cognitive function. We here used four behavioral tests to evaluate pain sensitivity and cognitive function in ARS and CRS mice. CRS markedly decreased Paw Withdrawal Mechanical Threshold (PWMT) and Tail-flick Latency (TFL) scores, whereas ARS altered TFL but had no effect on PWMT scores. Additionally, CRS, but not ARS, significantly changed behaviors in nest building behavior and MWMT. Intriguingly, the expression of Keap1 and Nrf2 protein were decreased in the spinal cord and hippocampus in CRS mice, but not in ARS mice. Moreover, neither the ARS nor the CRS groups significantly differed from the control group in terms of endoplasmic reticulum stress (ERS). Taken together, this study demonstrated that CRS could induce abnormal pain sensitivity and cognitive function probably via Keap1/Nrf2 pathway in spinal cord and hippocampus. It is therefore likely that effective intervention of Keap1/Nrf2 pathway may contribute to preventing and treating hyperalgesia and cognitive dysfunction in CRS.

Regional immunity involved in the maintenance and imbalance of periodontal homeostasis

The concept of homeostatic medicine has helped the researchers to understand the periodontal tissues in a completely new dimension. Periodontal tissues are subjected to complex external environmental stimuli and the internal tissues are continuously undergoing active remodeling. Periodontal regional immunity is continuously activated by local stimuli and interacts with the epithelial barrier, stromal tissue/extracellular matrix, and bone-coupled systems in a complex manner. Together, this complex network shapes the periodontal homeostasis. Under physiological conditions, moderate regional immunity relies on barrier function, intrinsic immune cells to control periodontal microbiota and maintain homeostasis. Under pathological conditions, pathogenic microbiota drive the periodontal homeostasis imbalance through over-activated regional immunity such as neutrophils, helper T (Th) 17 cells and B cells, causing periodontitis. Using the most basic immunological classification as a framework, this paper provides a systematic overview of the above mechanisms by which regional immunity regulates periodontal homeostasis, reviews the translational studies that have been carried out on homeostatic remodeling strategies targeting regional immunity, and proposes a series of periodontal homeostasis medicine research directions worth exploring, as well as potential new targets and strategies for homeostatic remodeling.

Особливості психічного стану у кваліфікованих борців

Purpose: research of psychical state in qualified wrestlers in stage of special basic fitness. Material and methods. The study involved 31 skilled Greco-Roman wrestlers aged 14-16 years, pupils of the wrestling club in Kremenchuk. To assess the mental state of skilled wrestlers, the Luscher color test was used. According to the results of the study, the following indicators were obtained: performance, fatigue, anxiety, deviation from the autogenous norm, eccentricity, concentricity, vegetative coefficient, heteronomy and autonomy. Heart rate variability was studied as an indicator of mental stress. The cardiac monitor «Fazagraf» was used. Based on the results of the study, we obtained statistical processing indicators and spectral characteristics of cardiac intervals. Non-parametric statistics with the determination of the median, lower and upper quartiles were used to assess the differences between the studied parameters. Results: in wrestlers with high tension of the autonomic regulation system, a deterministic functional system aimed at ensuring the mental state is revealed. At the same time, an increase in the tension of autonomic regulation is accompanied by mental fatigue, anxiety, passivity and the presence of mental stress. Prevention of mental stress in skilled wrestlers may be associated with the activation of the athlete to external environmental stimuli, optimism and a mood for positive behavior. The relationship between the indicators of mental state and the parameters of mental functions in skilled wrestlers was revealed. The moderate tension of the heart rate regulation system in skilled wrestlers is accompanied by an increase in mental performance and a decrease in anxiety. In turn, the increase in the tension of autonomous regulation is reflected in the presence of internal psychological discomfort and independence in the formation of decision-making. However, there is an increase in anxiety and a decrease in mental performance. Conclusions. The relationship between indicators of mental state and parameters of psychical functions in qualified wrestlers was revealed. Moderate tension of the heart rhythm regulation system in qualified wrestlers is accompanied by an increase in mental capacity and a decrease in anxiety. The increase in the tension of autonomous regulation in qualified wrestlers is reflected in the presence of internal psychological discomfort and independence in decision-making. Keywords: mental state, qualified wrestlers, heart rate regulation, indicators, analysis.

Eu3+ -Directed Supramolecular Metallogels with Reversible Quadruple-Stimuli Response Behaviors.

Smart luminescent materials that have the ability to reversibly adapt to external environmental stimuli and possess a wide range of responses are continually emerging, which place higher demands on the means of regulation and response sites. Here, europium ions (Eu3+ )-directed supramolecular metallogels are constructed by orthogonal self-assembly of Eu3+ based coordination interactions and hydrogen bonding. A new organic ligand (L) is synthesized, consisting of crown ethers and two flexible amide bonds-linked 1,10-phenanthroline moieties to coordinate with Eu3+ . Synergistic intermolecular hydrogen bonding in L and Eu3+ -L coordination bonding enable Eu3+ and L to self-assemble into shape-persistent 3D coordination metallogels in MeOH solution. The key to success is the utilization of crown ethers, playing dual roles of acting both as building blocks to build L with C2 -symmetrical structure, and as the ideal monomer for increasing the energy transfer from L to Eu3+ 's excited state, thus maintaining the excellent luminescence of metallogels. Interestingly, such assemblies show K+ , pH, F- , and mechano-induced reversible gel-sol transitions and tunable luminescence properties. Above findings are useful in the studies of molecular switches, dynamic assemblies, and smart luminescent materials.

Extracellular vesicles derived from mesenchymal stem cells: the wine in Hebe's hands to treat skin aging.

Owing to its constant exposure to the external environment and various stimuli, skin ranks among the organs most vulnerable to manifestations of aging. Preventing and delaying skin aging has become one of the prominent research subjects in recent years. Mesenchymal stem cells (MSCs) are multipotent stem cells derived from mesoderm with high self-renewal ability and multilineage differentiation potential. MSC-derived extracellular vesicles (MSC-EVs) are nanoscale biological vesicles that facilitate intercellular communication and regulate biological behavior. Recent studies have shown that MSC-EVs have potential applications in anti-aging therapy due to their anti-inflammatory, anti-oxidative stress, and wound healing promoting abilities. This review presents the latest progress of MSC-EVs in delaying skin aging. It mainly includes the MSC-EVs promoting the proliferation and migration of keratinocytes and fibroblasts, reducing the expression of matrix metalloproteinases, resisting oxidative stress, and regulating inflammation. We then briefly discuss the recently discovered treatment methods of MSC-EVs in the field of skin anti-aging. Moreover, the advantages and limitations of EV-based treatments are also presented.

Aging alters functional connectivity of motor theta networks during sensorimotor reactions

ObjectiveBoth cognitive and primary motor networks alter with advancing age in humans. The networks activated in response to external environmental stimuli supported by theta oscillations remain less well explored. The present study aimed to characterize the effects of aging on the functional connectivity of response-related theta networks during sensorimotor tasks. MethodsElectroencephalographic signals were recorded in young and middle-to-older age adults during three tasks performed in two modalities, auditory and visual: a simple reaction task, a Go-NoGo task, and a choice-reaction task. Response-related theta oscillations were computed. The phase-locking value (PLV) was used to analyze the spatial synchronization of primary motor and motor control theta networks. ResultsPerformance was overall preserved in older adults. Independently of the task, aging was associated with reorganized connectivity of the contra-lateral primary motor cortex. In younger adults, it was synchronized with motor control regions (intra-hemispheric premotor/frontal and medial frontal). In older adults, it was only synchronized with intra-hemispheric sensorimotor regions. ConclusionsMotor theta networks of older adults manifest a functional decoupling between the response-generating motor cortex and motor control regions, which was not modulated by task variables. The overall preserved performance in older adults suggests that the increased connectivity within the sensorimotor network is associated with an excessive reliance on sensorimotor feedback during movement execution compensating for a deficient cognitive regulation of motor regions during sensorimotor reactions. SignificanceNew evidence is provided for the reorganization of motor networks during sensorimotor reactions already at the transition from middle to old age.

Meta-analysis of influence of yoga activities on reaction time as a component of skill related fitness

Introduction: Yoga practices are known to have beneficial effect on cognitive functions. Reaction is a purposeful voluntary response to external stimuli. Reaction time is a component of skill related fitness. Humans gives response to different external environmental stimuli with different speed. Majority of daily work is done in response to visual and auditory stimuli. Yoga practices may improve reaction time. Objectives: To study influence of yoga practices on auditory reaction time and visual reaction time. Methods: Researchers used the Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) guidelines for reporting systematic reviews and meta-analysis. Researchers searched articles on PubMed, Google scholar and by manual search. Searched articles were screened for relevancy. By use of inclusion and exclusion criteria potential articles were selected. Results: Out of 287articles, finally 5 studies included in current meta-analysis. Yoga activities has effect on visual reaction time (VRT): SMD = 3.06, 95% CI = –0.66–6.78, P < 0.01 and auditory reaction time (ART): SMD = 2.86, 95% CI = –0.37–6.09. Conclusion: Yogic activities can provide beneficial effect on reaction time. Improved reaction time is important for reactive activity like sports. Yoga can be useful as a part of training in skill related work. There is wide scope for further studies to evaluate beneficial effects of yoga activities.

Research progress of nociplastic pain in the clinical treatment of chronic pain diseases

Chronic pain is increasingly developing into a worldwide health problem. Due to the money and treatment required for care and rehabilitation, as well as the complexity of the various types of pain, chronic pain sufferers often bear a huge financial burden as well as a psychological one. According to statistics, 23% of chronic pain sufferers have suicidal thoughts. In 2017, the third category pain named "nociplastic pain" was proposed for the first time by the International Association for the Study of Pain (IASP) which is disparate with the first kind nociceptive pain and the second pain neuropathic. The physiological mechanisms behind this type of pain are not known. However, it is commonly thought to be associated with a hypersensitivity response in the central nervous system and can be resulted in chronic nociceptive pain, so nociplastic pain is able to occur by itself, and can combine with other pain. At the same time, this type of pain affects the central system and produces other derived symptoms. Examples include stimulation of the limbic system, including impaired processing of emotions by the amygdala, amplified pain perception, sleep disturbances, increased fatigue and sensitivity to external environmental stimuli. There are no very clear and obvious diagnostic criteria or methods, and clinical detection is difficult. Due to the many symptoms, patients usually undergo multiple tests, with high medical costs and a poor prognosis. Patients suffer both physical and psychological distress. The disease with its complexity characteristic leads the difficulty for doctors to diagnosis it plagues patients with the condition, while increasing the difficulty of medical diagnosis and the cost of medical treatment. This article synthesizes the existing developments in outcomes in nociplastic pain from introduction and classification to diagnosis and treatment, it discusses the existing research findings.

Reduced neural connectivity in the caudate anterior head predicts hallucination severity in schizophrenia.

Caudate functional abnormalities have been identified as one critical neural substrate underlying sensory gating impairments that lead to auditory phantom hallucinations in both patients with schizophrenia (SZ) and tinnitus, characterized by the perception of internally generated sounds in the absence of external environmental auditory stimuli. In this study, we tested the hypothesis as to whether functional connectivity abnormalities in distinct caudate subdivisions implicated in sensory gating and auditory phantom percepts in tinnitus, which are currently being localized for neuromodulation targeting using deep brain stimulation techniques, would be associated with auditory phantom hallucination severity in SZ. Twenty five SZ and twenty eight demographically-matched healthy control (HC) participants, completed this fMRI resting-state study and clinical assessments. Between-group seed-to-voxel analyses revealed only one region, the caudate anterior head, which showed reduced functional connectivity with the thalamus that survived whole-brain multiple comparison corrections. Importantly, connectivity between the caudate anterior head with thalamus negatively correlated with hallucination severity. In the present study, we deliver the first evidence of caudate subdivision specificity for the neural pathophysiology underlying hallucinations in schizophrenia within a sensory gating framework that has been developed for auditory phantoms in patients with tinnitus. Our findings provide transdiagnostic convergent evidence for the role of the caudate in the gating of auditory phantom hallucinations, observed across patients with SZ and tinnitus by specifying the anterior caudate division is key to mediation of hallucinations, and creating a path towards personalized treatment approaches to arrest auditory phantom hallucinations from reaching perceptual awareness.

The Stimulus-Organism-Response (S-O-R) Paradigm as a Guiding Principle in Environmental Psychology: Comparison of its Usage in Consumer Behavior and Organizational Culture and Leadership Theory

The Stimulus-Organism-Response (S-O-R) paradigm developed by Mehrabian and Russell in 1974 is a guiding principle of environmental psychology theory and transferred from consumer behavior to organizational behavior and leadership studies. The S-O-R model suggests that an organism’s internal feelings or Behavior (person) are caused by the external environment (stimuli). This internal processing of the activation can be conscious or unconscious and includes perceptions and environmental interpretations that influence someone’s feelings. This influence further triggers an emotion that leads to a response and decision-making. The S-O-R paradigm is a leading concept in multiple global management theories and is, therefore, a model mainly developed and used in various research fields. This paper presents an analysis in the form of a scoping literature review of prior and current research dimensions of the S-O-R model in branding and consumer behavior theory. It compares the usage of the model in branding theory to the usage in organizational Behavior and leadership theory. Besides a summary of similarities of the same model used in both research fields, three main differencing correlations and characteristics have been developed and described. The main differencing factors are the motivation and aim of usage of the model itself, the process and relation of the stimuli-organism-reaction stages, and certain moderating variables and influencing factors throughout the decision-making process, such as marketing, branding on the one hand or leadership and organizational culture on the other hand.

Unraveling the adaptive chemical traits of Rhamnidium elaeocarpum Reissek in response to fire in pantanal wetlands

We conducted a study on the effects of fire on Rhamnidium elaeocarpum, a widely distributed woody species found in the Pantanal wetlands, using LC–MS metabolomics, total phenolic and tannin content analysis, and thermogravimetric behavior. We sampled individuals from four groups: No Fire, Fire 2019, Fire 2020, and APD 20 (individuals whose aerial parts had died during the 2020 fire event). We found that recent fires had no significant impact on the species' phenolic metabolism except for those in the fourth group. These specimens showed a decline in secondary metabolites due to leaching. The high levels of phenolics in R. elaeocarpum suggest that this species has a biochemical tolerance to the stress caused by seasonal fires. Metabolomic profiling revealed the presence of proanthocyanidin oligomers, which protect against oxidative stress and post-fire environmental disturbances. However, the passage of fire also led to a high incidence of toxic karwinaphthopyranone derivatives, which could be a concern for the species' medicinal use. Finally, the thermogravimetric analysis showed that the species is thermotolerant, with an intrinsic relationship between the secondary compounds and thermotolerance. Our research has deepened the comprehension of how fire affects the metabolic processes of woody plants. The challenge now lies in determining if the identified chemical changes are adaptive characteristics that evolved over time or merely transient responses to external environmental stimuli.

Smart dental materials for antimicrobial applications.

Smart biomaterials can sense and react to physiological or external environmental stimuli (e.g., mechanical, chemical, electrical, or magnetic signals). The last decades have seen exponential growth in the use and development of smart dental biomaterials for antimicrobial applications in dentistry. These biomaterial systems offer improved efficacy and controllable bio-functionalities to prevent infections and extend the longevity of dental devices. This review article presents the current state-of-the-art of design, evaluation, advantages, and limitations of bioactive and stimuli-responsive and autonomous dental materials for antimicrobial applications. First, the importance and classification of smart biomaterials are discussed. Second, the categories of bioresponsive antibacterial dental materials are systematically itemized based on different stimuli, including pH, enzymes, light, magnetic field, and vibrations. For each category, their antimicrobial mechanism, applications, and examples are discussed. Finally, we examined the limitations and obstacles required to develop clinically relevant applications of these appealing technologies.

Sponge-like, semi-interpenetrating self-sensory hydrogel for smart photothermal-responsive soft actuator with biomimetic self-diagnostic intelligence

Actuators based on hydrogels are good candidates for biomimetic soft robots due to their excellent mechanical properties and flexibility. Despite great efforts in hydrogel-based actuators, their actuation process still differs from the “recognition-judgment-execution” process that conscious intelligent beings go through owing to the lack of perceptive capacity. Herein, to imitate the intelligent actuation process of conscious organisms, a fast photo-thermal responsive and self-sensory soft actuator is proposed based on sponge-like hydrogel with semi-interpenetrating (semi-IPN) polymer network of thermosensitive poly (N-isopropylacrylamide) (PNIPAM) and electronically conductive polyaniline (PANI). The proposed actuator exhibits excellent photo-thermal responsiveness enabling remotely triggered actuation controlled by near infrared light (NIR), covering all azimuths with ultrafast response rate (within 2 s) and recover rate (within 1 s). Meanwhile, the conformational transition of PNIPAM networks during the course of actuation also lead to accompanying migration of the interpenetrated PANI chains and significant variation of local conductivity (>15%), endowing the actuator with self-sensing capacity to monitor its deformations. Eventually, a smart self-adaptive actuator is designed inspired by neuromuscular in intelligent organisms, which can actively perceive external environmental stimuli and consciously regulate its own shape transformation by monitoring and analyzing electrical signal. This sensory actuating hydrogel can provide insights into the development of artificial intelligent soft robotics with higher levels of autonomy and complexity.