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Pickering nanoemulsions were prepared using dual-protein natural symbiotic particles and their physicochemical stability was analyzed to broaden their potential application in the food industry. This study employed alkali extraction-isoelectric point precipitation (AE) and salt extraction-dialysis (SE) to enrich soy protein and flaxseed protein from soybean-flaxseed mixed meal for fabricating dual-protein symbiotic natural particles (SFNPs). First, two dual-protein symbiotic particles were characterized using appearance observation, AFM, circular dichroism, and Raman spectroscopy. Then, Pickering nanoemulsions were prepared with them as particle stabilizers and characterized for their physical and chemical stability. Results demonstrated that AE-SFNPs had a higher uniformity of size and better dispersibility. AE-SFNPs also showed a higher proportion (as high as 51.25%) of β-sheet in its secondary structure, endowing it a more tightly ordered and flexible structure compared with SE-SFNPs. Moreover, both AE-SFNPs and SE-SFNPs could be used to generate Pickering nanoemulsion. During 28 days of storage, the particle size of the stabilized emulsion of AE-SFNPs increased only about 14 nm and its ζ-potential was stabilized at about -34 mV. In contrast, the particle size of the stabilized emulsion of SE-SFNPs increased about 12 fold, and its ζ-potential was decreased 1.32 fold. The stability index (TSI, 5.83) of the AE-SFNPs was much smaller than the TSI value (55.13) of the SE-SFNPs when stored until the 28th day. Notably, the Pickering nanoemulsion stabilized by AE-SFNPs exhibited higher physical and chemical stability than that prepared by sodium caseinate (a common emulsifier used in food processing). Therefore, AE-SFNPs can serve as a natural and efficient plant protein-based particle stabilizer to prepare Pickering nanoemulsion. This work provides a new strategy to enhance the industrial application of nanoemulsions.

During the extraction of membrane proteins from oil bodies (OBs), organic solvents dissolve the lipid core and precipitate proteins through solvent stress. Here the effects of solvent type and defatting sequence on the composition and structure of membrane proteins were investigated via SDS-PAGE, FTIR, and SEM-EDS. High purity oleosin (86 %) was obtained by treatment first with a Floch solution and then with cold acetone and petroleum ether after twice washing OBs with urea. The 3D spatial structure of oleosin was predicted using AlphaFold 2, revealing that the secondary structure of oleosin was dominated by α-helices (>60 %). Oleosin consisted of two district types, with oleosin-H (16–17 kDa) being the part of the molecule with limited water solubility, while oleosin-L (13–14 kDa) constituted the non-soluble part. The results provided a technical means of efficient extraction of Camellia oleosins and selective separation of oleosin-L and oleosin-H.

Abstract Non‐volatile photomemory based on photomodulated luminescent materials offers unique advantages over voltage‐driven memory, including low residual crosstalk and high storage speed. However, conventional materials have thus far been volatile and insecure for data storage because of low trap depth and single‐level storage channels. Therefore, the development of a novel non‐volatile multilevel storage medium for data encryption remains a challenge. Herein, a robust, non‐volatile, multilevel optical storage medium is reported, based on a photomodulated Ba3MgSi2O8:Eu3+, which combined the merits of light‐induced valence (Eu3+ → Eu2+) and photochromic phenomena using optical stimulation effects, accompanied by larger luminescent and color contrasts (>90%). These two unique features provided dual‐level storage channels in a single host, significantly improving the data storage security. Notably, dual‐level optical signals could be written and erased simultaneously by alternating 265 and 365 nm light stimuli. Theoretical calculations indicated that robust color centers induced by intrinsic interstitial Mg and vacancy defects with suitable trap depths enable excellent reversibility and long‐term storage capability. By relying on different luminescent readout mechanisms, the encrypted dual‐level information can be accurately decrypted by separately probing the Eu2+ and Eu3+ signals, thus ensuring information security. This study proposes a novel approach for constructing multilevel information storage channels for information security.

Abstract Distinct types of luminescence that are activated by various stimuli in a single material offer exciting developmental opportunities for functional materials. A versatile sensing platform that exhibits photoluminescence (PL), persistent luminescence (PersL), and mechanoluminescence (ML) is introduced, which enables the sensitive detection of temperature, pressure, and force/stress. The developed Sr2MgSi2O7:Eu2+/Dy3+ material exhibits a linear relationship between ML intensity and force and can be used as an ML stress sensor. Additionally, the bandwidth of the PL emission band and the PL lifetime of this material are remarkably sensitive to temperature, with values of ≈0.05 nm K−1 and 1.29%/K, respectively. This study demonstrates PersL pressure sensing for the first time, using long‐lasting (seconds) lifetime as a manometric parameter. The developed material functions as an exceptionally sensitive triple‐mode visual pressure sensor; specifically, it exhibits: i) a sensitivity of ≈−297.4 cm GPa−1 (8.11 nm GPa−1) in bandshift mode, ii) a sensitivity of ≈272.7 cm−1/GPa (14.8 nm GPa−1) in bandwidth mode, and iii) a sensitivity of 42%GPa−1 in PL‐lifetime mode, which is the highest value reported to date. Notably, anti‐counterfeiting, night‐vision safety‐sign, 8‐bit optical‐coding, and QR‐code applications that exhibit intense PersL are demonstrated by 3D‐printing the studied material in combination with a polymer.

Photo-stimuli responsive materials show great potential in the fields of information encryption and storage due to their distinctive spatial or temporal color changes. However, the conventional single or multi-color static outputs by light stimulus difficulty meet practical requirements for high-security optical storage technologies. Here, a novel dynamic irradiation-responsive phosphor of Na2Ba2Si2O7:Eu is demonstrated, exhibiting high storage stability and convenient readout behaviors. The inherent Eu2+ luminescence can be dynamically tuned, instantly read out, and conveniently erased by controlling irradiation duration of a portable diode laser (365 nm). The modulation mechanism is unraveled by optically induced oxidation reactions of Eu2+→Eu3+ and defects as killer centers. The excellent luminescence modulation degree (ΔRt = 89.5%) and the accompanying larger color contrast enable the creation of invisible optical codes with multi-level encryption in bright or dark field. These results indicate potential applications of Na2Ba2Si2O7-based materials in information encryption and invisible optical storage, and are expected to expand more investigations on optically induced PL modulation behaviors based on mixed valences and defects.

Abstract Mechanoluminescence (ML) sensing technologies open up new opportunities for intelligent sensors, self-powered displays and wearable devices. However, the emission efficiency of ML materials reported so far still fails to meet the growing application requirements due to the insufficiently understood mechano-to-photon conversion mechanism. Herein, we propose to quantify the ability of different phases to gain or lose electrons under friction (defined as triboelectric series), and reveal that the inorganic-organic interfacial triboelectricity is a key factor in determining the ML in inorganic-organic composites. A positive correlation between the difference in triboelectric series and the ML intensity is established in a series of composites, and a 20-fold increase in ML intensity is finally obtained by selecting an appropriate inorganic-organic combination. The interfacial triboelectricity-regulated ML is further demonstrated in multi-interface systems that include an inorganic phosphor-organic matrix and organic matrix-force applicator interfaces, and again confirmed by self-oxidization and reduction of emission centers under continuous mechanical stimulus. This work not only gives direct experimental evidences for the underlying mechanism of ML, but also provides guidelines for rationally designing high-efficiency ML materials.

Abstract The quest for mechanoluminescence (ML) in zinc sulfide (ZnS) spans more than a century, initially sparked by observations of natural minerals. There has been a resurgence in research into ML materials in recent decades, driven by advances in optoelectronic technologies and a deeper understanding of their luminescent properties under mechanical stress. ZnS, in particular, has garnered attention owing to its remarkable ability to sustain luminescence after more than 100,000 mechanical stimulations, positioning it as a standout candidate for optoelectronic applications. In contrast to conventional photoluminescent and electroluminescent light sources, ZnS composite elastomers have emerged as flexible, stretchable self‐powered light sources with considerable practical implications. This review introduces the development history, ML mechanisms, prototype ML devices, ZnS‐based ML material preparation methods, and their diverse applications spanning environmental mechanical‐to‐optical energy conversion, E‐signatures, anti‐counterfeiting, wearable information sensing devices, advanced battery‐free displays, biomedical imaging, and optical fiber sensors for human–computer interactions, among others. By integrating insights from ML‐optics, mechanics, and flexible optoelectronics, and by summarizing pertinent perspectives on current scientific challenges, application technology hurdles, and potential solutions for emerging scientific frontiers, this review aims to furnish fundamental guidance and conceptual frameworks for the design, advancement, and cutting‐edge application of novel mechanoluminescent materials.

Abstract Visible light‐based human–machine interactive media is capable of transmitting electrical readouts to machines and providing intuitive feedback to users simultaneously. Currently, many inorganic mechanoluminescent (ML) materials‐based interactive media, typically ZnS‐loaded phosphors (ZLPs), have been successfully demonstrated. However, organic ML materials‐based solutions were rarely exploited despite their huge merits of strong structural modification, abundant luminescence property, low cost, easy preparation, and so on. Here, we propose a novel interactive tactile display (ITD) based on organic ML materials (Cz‐A6‐dye) and triboelectric nanogenerator, with ultra‐brightness (130% enhancement) and ultra‐low threshold pressure (57% reduction) as compared to ZLPs. The proposed ITD achieves the conversion of weak mechanical stimuli into visible light and electrical signals simultaneously, without extra power supplies. Furthermore, the relationship between the luminous performance of organic ML materials and mechanical force is quantified, benefiting from the uniform ML layer prepared. Enabled by convolutional neural networks, the high‐accuracy recognition (97.1%) for handwriting and identity of users is realized at the same time. Thus, the ITD has great potential for intelligent wearable electronics and classified military applications.

Gliadin nanoparticle (GNP) is a promising foaming agent, but its application is hindered by the limited foam stability under low acidic conditions. Herein, we attempted to tune the foam stability of GNP by coating it with flaxseed gum (FG) and investigated the structure, interfacial behaviors, and foam functionality of gliadin-FG (GFG) particles at pH 4.5. Results showed that the formation of GFG complex particles was driven by an electrostatic interaction between positive charge patches on the surface of GNP (~17 mV) and negative charges in FG molecule (~−13 mV) at all tested ratios. The addition of appropriate amounts of FG (1:0.05) effectively improved the foam stability of GNP. This was because GFG with larger sizes and lower surface charge possessed higher rigidity after coating with FG. When they adsorbed at the air/water interface, their deformation process was slower than that of GNP, as indicated by interfacial dilatational rheology and cryo-SEM, and the covered particles seemed to be more closely distributed to form solid-like and dense interfacial films. Notably, the addition of FG at a higher ratio (1:0.3) promoted the foam stability of GNP by about five folds because the larger GFG with suitable flexibility and wettability could form a stiff interface layer with more significant elastic response, and the unabsorbed particles and FG could form a gel-like network structure in the continuous phase. These characteristics effectively prevented foam disproportionation and coalescence, as well as retard the drainage. Our findings demonstrate that coating GNPs with FG is an effective approach to improve their application in foamed foods.

Abstract Mechanoluminescence is a smart light‐emitting phenomenon in which applied mechanical energy is directly converted into photon emissions. In particular, mechanoluminescent materials have shown considerable potential for applications in the fields of energy and sensing. This study thoroughly investigates the mechanoluminescence and long afterglow properties of singly doped and codoped Sr2MgSi2O7(SMSO) with varying concentrations of Eu2+ and Dy3+ ions. Subsequently, a comprehensive analysis of its multimode luminescence properties, including photoluminescence, mechanoluminescence, long afterglow, and X‐ray‐induced luminescence, is conducted. In addition, the density of states mapping is acquired through first‐principles calculations, confirming that the enhanced mechanoluminescence properties of SMSO primarily stem from the deep trap introduced by Dy3+. In contrast to traditional mixing with Polydimethylsiloxane, in this study, the powders are incorporated into optically transparent wood to produce a multiresponse with mechanoluminescence, long afterglow, and X‐ray‐excited luminescence. This structure is achieved by pretreating natural wood, eliminating lignin, and subsequently modifying the wood to overall modification using various smart phosphors and epoxy resin composites. After natural drying, a multifunctional composite wood structure with diverse luminescence properties is obtained. Owing to its environmental friendliness, sustainability, self‐power, and cost‐effectiveness, this smart mechanoluminescence wood is anticipated to find extensive applications in construction materials and energy‐efficient displays.

This study characterized and compared the physical and emulsifying properties of pea protein (PP) and its modified proteins (ultrasound treated- PP (PPU), flaxseed gum (FG) treated PP (PPFG) and ultrasound treated- PPFG (PPFGU)). The results showed FG triggered the formation of loosely attached complex with PP via physical modification under gentle magnetic stirring at pH 7.0, while ultrasound played an important role in reducing protein size, increasing surface hydrophobicity and molecular fluidity onto oil-water interface. So ultrasound further enhanced the interaction of PP with FG, and produced the PPFGU complex with smaller droplet size, higher ζ-potential and lower turbidity. Further, combination of FG and ultrasound improved the physical properties of PP with higher viscosity, stiffer gels (defined as higher elastic modulus), stronger hydrophobic properties, better thermal stability, and fast protein absorption rate. Therefore, the PPFGU coarse emulsion performed highest emulsifying activity index (EAI) and emulsion stability index (ESI) that the stabilized nanoemulsion obtained smallest droplet size, higher ζ-potential, and longest storage stability. The combination of FG and ultrasonic treatment will be an effective approach to improving the emulsifying property and thermal stability of PP, which can be considered as a potential plant-based emulsifier applied in the food industry.

The ability to locate and quantify large strains will significantly improve the real‐world application scenario of flexible and stretchable strain sensors. However, current methods for implementing stretchable distributed strain sensing still face challenges such as complicated demodulation, multisensor crosstalk, and high power consumption. Herein, a self‐powered and stretchable optical fiber strain sensor is reported with distributed sensing capability based on mechanoluminescent optical fiber, where mechanoluminescent phosphors with different emission color light are discretely integrated onto the outer cladding of the elastomer optical fiber. Based on the wavelength coding technique and time‐domain filtering comparison method, the capability of strain magnitude quantification (10–60%) and strain location identification together in a single stretchable optical fiber is successfully realized, even at multiple positions simultaneously in the strain‐applied situation. Moreover, this stretchable optical fiber strain sensor shows insensitivity to bending, compression, and temperature disturbances and outstanding durability (>8000 cycles). Due to the excellent light confinement of the elastomer optical fiber, demonstrations such as bright‐field measurement, saline water operation, and wearable glove application exhibit its potential as a promising technology for future self‐powered distributed optical sensing systems.

Abstract Flexible organic materials that exhibit dynamic ultralong room temperature phosphorescence (DURTP) via photoactivation have attracted increasing research interest for their fascinating functions of reversibly writing-reading-erasing graphic information in the form of a long afterglow. However, due to the existence of a nonnegligible activation threshold for the initial exposure dose, the display mode of these materials has thus far been limited to binary patterns. By resorting to halogen element doping of carbon dots (CDs) to enhance intersystem crossing and reduce the activation threshold, we were able to produce, for the first time, a transparent, flexible, and fully programmable DURTP composite film with a reliable grayscale display capacity. Examples of promising applications in UV photography and highly confidential steganography were constructed, partially demonstrating the broad future applications of this material as a programmable platform with a high optical information density.

Mechanoluminescence (ML) sensors offer full-field strain/stress measurements and have the advantages of easy implementation, non-invasiveness, and low cost. However, knowledge of the mechanism of carrier detrapping owing to mechanical forces remains elusive as it may include one or more complicated processes. Several attempts to develop calibration models for converting the light emitted by ML sensors into mechanical stress have been reported, but few studies have tested the ML response under static or quasi-static loading rates. In this study, we built a real-time measurement system to evaluate the constitutive strain-luminescence relationship of ML sensors. The ML response was investigated at loading rates as low as 5 µm/s (i.e., strain rates as low as 16.2 μst/s). The results showed that the light of ML sensors was still excited under quasi-static loading rates. A double-exponential function was applied to describe nonlinear changes in light intensity over time. We used this function to modify the previous model and predict the ML responses under variable loading rate conditions. The results predicted by the model proposed in this paper are in good agreement with the experimental results.

Abstract Mechanoluminescence, a smart luminescence phenomenon in which light energy is directly produced by a mechanical force, has recently received significant attention because of its important applications in fields such as visible strain sensing and structural health monitoring. Up to present, hundreds of inorganic and organic mechanoluminescent smart materials have been discovered and studied. Among them, strontium‐aluminate‐based materials are an important class of inorganic mechanoluminescent materials for fundamental research and practical applications attributed to their extremely low force/pressure threshold of mechanoluminescence, efficient photoluminescence, persistent afterglow, and a relatively low synthesis cost. This paper presents a systematic and comprehensive review of strontium‐aluminate‐based luminescent materials’ mechanoluminescence phenomena, mechanisms, material synthesis techniques, and related applications. Besides of summarizing the early and the latest research on this material system, an outlook is provided on its environmental, energy issue and future applications in smart wearable devices, advanced energy‐saving lighting and displays.

Mechanoluminescence (ML) materials, which directly convert mechanical energy into light emission, have emerged as an emerging class of light-emitting materials with various applications. Although significant progress has been made in the development of new ML materials and devices, their practical application is limited by their low intensity and homogenously structured host structures. Thus, multiple-structured host ML materials with high ML intensity and reproducibility are needed, particularly for wearable and printable ML light sources with high brightness. In this study, various Mn-doped ternary heterojunction ML materials, CaZnOS-ZnS-SrZnOS, are synthesised by high-temperature solid-phase reactions, and their luminescence properties are systematically tested. The result indicates that the ternary heterojunction materials have a higher ML intensity over 60 times stronger than the state-of-art SrZnOS: Mn2+, which is currently the brightest sample we have obtained. ML linearly depends on the magnitude of the applied force. Based on the synthesised ternary ML heterojunctions, repetitive self-driving luminescence of the zipper is achieved for the first time through powder modification and inlay; the clothes composed of our prepared zippers are pulled and bent when worn on the body to emit bright visible light. Additionally, a Velcro that can achieve light emission is developed; it provides a new idea for the development of wearable flexible self-luminous devices in the future. Simultaneously, movement-driven stress luminous printable objects that can be printed on the surface of various commodities or their packaging are demonstrated. The preparation of self-driven, battery-free, and electrode-free stress luminescence wearable low light sources has an important application trend, which can avoid the interference of the circuit and improve the stability of the devices, thus promising a wide range of applications in smart wear, energy-saving displays, safety and rescue, robotic skin, and information security.

Organic mechanophores have been widely adopted for polymer mechanotransduction. However, most examples of polymer mechanotransduction inevitably experience macromolecular chain rupture, and few of them mimic mussel’s mechanochemical regeneration, a mechanically mediated process from functional units to functional materials in a controlled manner. In this paper, inorganic mechanoluminescent (ML) materials composed of CaZnOS-ZnS-SrZnOS: Mn2+ were used as a mechanotransducer since it features both piezoelectricity and mechanolunimescence. The utilization of ML materials in polymerization enables both mechanochemically controlled radical polymerization and the synthesis of ML polymer composites. This procedure features a mechanochemically controlled manner for the design and synthesis of diverse mechanoresponsive polymer composites.

Abstract Mechanoluminescent (ML) materials that directly convert mechanical energy into photon emission have emerged as promising candidates for various applications. Despite the recent advances in the development of both novel and conventional ML materials, the limited access to ML materials that simultaneously have the attributes of high brightness, low cost, self‐recovery, and stability, and the lack of appropriate designs for constructing ML devices represent significant challenges that remain to be addressed to boost the practical application of ML materials. Herein, ML hybrids derived from a natural source, waste eggshell, with the aforementioned attributes are demonstrated. The introduction of the eggshell not only enables the preparation of the hybrid in a simple and cost‐effective manner but also contributes to the homochromatism (red, green, or blue emission), high brightness, and robustness of the resultant ML hybrids. The significant properties of the ML hybrids, together with the proposed structural design, such as porosity or core–shell structure, could expedite a series of mechanic‐optical applications, including the self‐luminous shoes for the conversion of human motions into light and light generators that efficiently harvest water wave energy. The fascinating properties, versatile designs, and the efficient protocol of “turning waste into treasure” of the ML hybrids represent significant advances in ML materials, promising a leap to the practical applications of this flouring material family.

Abstract Persistent mechanoluminescence (ML) with long lifetime is highly required to break the limits of the transient emitting behavior under mechanics stimuli. However, the existing materials with persistent ML are completely trap‐controlled, and a pre‐irradiation is required, which severely hinders the practical applications. In this work, a novel type of ML, self‐charging persistent ML, is created by compositing the Sr3Al2O5Cl2:Dy3+ (SAOCD) powders into flexible polydimethylsiloxane (PDMS) matrix. With no need for any pre‐irradiation, the as‐fabricated SAOCD/PDMS elastomer could exhibit intense and persistent ML under mechanics stimuli directly, which greatly facilitates its applications in mechanics lighting, displaying, imaging, and visualization. By investigating the matrix effects as well as the thermoluminescence, cathodoluminescence, and triboelectricity properties, the interfacial triboelectrification‐induced electron bombardment processes are demonstrated to be responsible for the self‐charged energy in SAOCD under mechanics stimuli. Based on the unique self‐charging processes, the SAOCD/PDMS further exhibits mechanics storage and visualized reading activities, which brings novel ideas and approaches to deal with the mechanics‐related problems in the fields of mechanical engineering, bioengineering, and artificial intelligence.

In order to expand the applications of plant protein in food formulations, enhancement of its functionalities is meaningful. Herein, the effects of ultrasonic (20 KHz, 400 W, 20 min)-assisted pH shift (pH 10 and 12) treatment on the structure, interfacial behaviors, as well as the emulsifying and foaming properties of perilla protein isolate (PPI) were investigated. Results showed that the solubility of PPI treated by ultrasonic-assisted pH shift (named UPPI-10/12) exceeded 90 %, which was at least 2 and 1.4 times that of untreated PPI and ultrasound-based PPI. Meanwhile, UPPI-10/12 possessed higher foamability (increasing by at least 1.2 times) and good emulsifying stability. Ultrasonic-assisted pH shift treatment decomposed large PPI aggregates into tiny particles, evident from the dynamic light scattering (DLS) and atomic force microscopy results. Besides, this approach induced a decrease in α-helix of PPI and an increase in β-sheet, which might result in the exposure of the hydrophobic group on the structural surface of PPI, thus leading to the increase of surface hydrophobicity. The smaller size and higher hydrophobicity endowed UPPI-10/12 faster adsorption rate, tighter interfacial structure, and higher elastic modulus at the air- and oil–water interfaces, evident from the cryo-SEM and interfacial dilatational rheological results. Thus, the emulsifying and foaming properties could evidently enhance. This study demonstrated that ultrasonic-assisted pH shift technique was a simple approach to effectively improve the functional performance of PPI.

Under the excitation of ultraviolet, X-ray, and mechanical stress, intense orange luminescence (Mn2+, 4T1 → 6A1) can be generated in Mn2+-doped SrZn2S2O crystal in orthorhombic space group of Pmn21. Herein, the multiple energy conversion in SrZn2S2O:Mn2+, that is, photoluminescence (PL), X-ray-induced luminescence, and mechanoluminescence, is investigated. Insight in luminescence mechanisms is gained by evaluating the Mn2+ concentration effects. Under the excitation of metal-to-ligand charge-transfer transition, the most intense PL is obtained. X-ray-induced luminescence shows similar features with PL excited by band edge UV absorption due to the same valence band to conduction band transition nature. Benefiting much from trap levels introduced by Mn2+ impurities, the quenching behavior mechanoluminescence is more like the directly excited PL from Mn2+ d-d transitions. Interestingly, this concentration preference leads to varying degrees of spectral redshift in each mode luminescence. Further, SrZn2S2O:Mn2+ exhibits a good linear response to the excitation power, which makes it potential candidates for applications in X-ray radiation detection and mechanical stress sensing.

With the capability of completing a task or achieving a goal in an uncertain environment while simultaneously having the characteristics of adaptability, self‐optimization, self‐diagnostics, and self‐maintenance, intelligent systems have witnessed extraordinary progress in recent years. These advances involve robotics, artificial intelligence and machine learning, automation, human–machine interfaces, the Internet of Things, control theory and control systems, smart and responsive materials, intelligent sensing systems, and programmed self‐assembly. As an active technology conveying mechanical stimuli to a wide range of electrical and optical signals, tactile sensors are essential elements of intelligent systems and have accelerated the emergence of advanced intelligent systems by enabling the accurate recognition and safe interaction of humans and machines, smart sensing of control systems, precise control of robotics, and synergetic work of artificial intelligent systems. Herein, the recent advances of tactile sensors for advanced intelligent systems are reviewed, emphasizing these with the working principles of piezoresistance, resistance, capacitance, piezoelectricity, triboelectricity, and optics. Representative examples of their applications in advanced intelligent systems, such as robotics, human–machine interfaces, and artificial intelligence, are explored. The remaining challenges and perspectives in this emerging field are also discussed.

Casticin has wide-ranging functional activities, but its water solubility is poor in food products. Here, a nanoemulsion stabilized by Maillard whey protein isolate conjugates (MWPI) was fabricated to encapsulate casticin. The nanoemulsion, with an average diameter of 200 nm, possessed the capability to load 700 μg/g casticin. MWPI-stabilized nanoemulsion showed better stability than that of the WPI nanoemulsion during 4 weeks of storage. Both the inhibition effects of the casticin-loaded nanoemulsion on cancer cells and the process of cellular uptake were studied. Results revealed that the casticin-loaded nanoemulsion had better inhibitory activity in HepG2 and MCF-7 cells than free casticin. Cellular uptake of the nanoemulsion displayed a time-dependent manner. After the nanoemulsion passed into HepG2 and MCF-7 cells, it would locate in the lysosome but not in the nucleus. The main pathway for the nanoemulsion to enter HepG2 cells was pinocytosis, whereas, it entered MCF-7 predominantly through the clathrin-mediated pit. This work implies that MWPI-stabilized nanoemulsions could be utilized as an effective delivery system to load casticin and have the potential to be applied in the food and pharmaceutical industries.

Phase and size of lanthanide-doped nanoparticles are the most important characteristics that dictate optical properties of these nanoparticles and affect their technological applications. Herein, we present a systematic study to examine the effect of alkaline earth doping on the formation of NaYF4 upconversion nanoparticles. We show that alkaline earth doping has a dual function of tuning particle size of hexagonal phase NaYF4 nanoparticles and stabilizing cubic phase NaYF4 nanoparticles depending on composition and concentration of the dopant ions. The study described here represents a facile and general strategy to tuning the properties of NaYF4 upconversion nanoparticles.

Er3+ and Yb3+ co-doped CaBi2Ta2O9 (CBT)-based bismuth layered-structure oxides were synthesized by a simple solid-state reaction method. Their up-conversion (UC) luminescence, dielectric and ferroelectric properties were investigated. Two strong green emission bands centered at 526 and 547 nm and a weak red emission band centered at 658 nm were obtained under a 980 nm laser excitation at room temperature. These emission bands originated from the radiative relaxation of Er3+ from 2H11/2, 4S3/2, and 4F9/2 levels to the ground state 4I15/2, respectively. At the meantime, the fluorescence intensity ratio (FIR) variation of two green UC emissions at 526 and 547 nm has been studied as a function of temperature in the range of 153–603 K. The maximum sensor sensitivity obtained was 39 × 10-4 K-1 at 590 K, which indicated that Er3+/Yb3+ co-doped CBT ceramic is a promising candidate for applications in optical high temperature sensor.

Er3+ doped SrBi4Ti4O15 (SBT) bismuth layered-structure ferroelectric ceramics were synthesized by the traditional solid-state method, and their upconversion photoluminescent (UC) properties were investigated as a function of Er3+ concentration and incident pump power. Green (555 nm) and red (670 nm) emission bands were obtained under 980 nm excitation at room temperature, which corresponded to the radiative transitions from 4S3/2, and 4F9/2 to 4I15/2, respectively. The emission color of the samples could be changed with moderating the doping concentrations. The dependence of UC intensity on pumping power indicated a two-photon emission process. Studies on dielectric properties indicated that the introduction of Er increased the ferroelectric-paraelectric phase transition temperature (Tc) of SBT, thus making this ceramic suitable for piezoelectric sensor applications at higher temperatures. Piezoelectric measurement showed that the doped SBT had a relative higher piezoelectric constant d33 compared with the non-doped ceramics. The thermal annealing behaviors of the doped sample revealed a stable piezoelectric property. The doped SBT showed bright UC emission while simultaneously having increased Tc and d33. As a multifunctional material, Er doped SBT ferroelectric oxide showed great potential in application of sensor, future optical-electro integration and coupling devices.