Host-Guest Interaction Mediated Interfacial Co-Assembly of Cyclodextrin and Bottlebrush Surfactants for Precisely Tunable Photonic Supraballs.

Investigations of host-guest interactions at water-oil (w/o) interfaces are limited in single emulsion systems producing simple self-assembled objects with limited uses. Here, within hierarchically ordered water-in-oil-in-water (w/o/w) multiple emulsion droplets, interfacial self-assembly of (polynorbornene-graft-polystyrene)-block-(polynorbornene-graft-polyethylene glycol) (PNPS-b-PNPEG) bottlebrush block copolymers can be precisely controlled through host-guest interactions. α-Cyclodextrin (α-CD) in the aqueous phase can thread onto PEG side chains of the bottlebrush surfactants adsorbed at the w/o interface, leading to dehydration and collapsed chain conformation of the PEG block. Consequently, spherical curvature of the w/o internal droplets increases with the increased asymmetry of the bottlebrush molecules, producing photonic supraballs with precisely tailored structural parameters as well as photonic bandgaps. This work provides a simple but highly effective strategy for precise manipulation of complex emulsion systems applicable in a variety of applications, such as photonic pigments, cosmetic products, pesticides, artificial cells, etc.

Photonic Pigments of Polystyrene-block-Polyvinylpyrrolidone Bottlebrush Block Copolymers via Sustainable Organized Spontaneous Emulsification.

Prior studies on photonic pigments of amphiphilic bottlebrush block copolymers (BBCPs) through an organized spontaneous emulsification (OSE) mechanism have been limited to using polyethylene glycol (PEG) as the hydrophilic side chains and toluene as the organic phase. Herein, a family of polystyrene-block-polyvinylpyrrolidone (PS-b-PVP) BBCPs are synthesized with PVP as the hydrophilic block. Biocompatible and sustainable anisole is employed for dissolving the obtained BBCPs followed by emulsification of the solutions in water. Subsequent evaporation of oil-in-water emulsion droplets triggers the OSE mechanism, producing thermodynamically stable water-in-oil-in-water (w/o/w) multiple emulsions with uniform and closely packed internal droplet arrays through the assembly of the BBCPs at the w/o interface. Upon solidification, the homogeneous porous structures are formed within the photonic microparticles that exhibit visible structural colors. The pore diameter is widely tunable (150∼314 nm) by changing the degree of polymerization of BBCP (69∼110), resulting in tunable colors across the whole visible spectrum. This work demonstrates useful knowledge that OSE can be generally used in the fabrication of ordered porous materials with tunable internal functional groups, not only for photonic applications, but also offers a potential platform for catalysis, sensing, separation, encapsulation, etc.

Experiences and perspectives on the optimal timing for initiating advance care planning in patients with mild to moderate dementia: A meta-synthesis.

BACKGROUND: Advance care planning is typically initiated during the last six months of a patient's life. However, due to the progressive decline in the decision-making process in individuals with dementia, their involvement in advance care planning is limited to the early stages of the disease. Currently, there is no consensus on the optimal timing for initiating advance care planning for people with dementia, and a comprehensive review of the literature addressing this matter is lacking. OBJECTIVE: To explore the experiences and perspectives of people with dementia, their family caregivers, and health care professionals with regard to the optimal timing for initiating advance care planning. DESIGN: A meta-synthesis was conducted. DATA SOURCE: The following eight electronic databases were searched: PubMed, Embase, Web of Science, Cochrane Library, CINAHL and CNKI, WanFang and Vip. REVIEW METHODS: This review uses thematic synthesis to systematically synthesize qualitative evidence and report findings according to The Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) and the Joanna Briggs Institute Manual for Evidence Synthesis. Study selection and data extraction were conducted independently by two researchers, and quality was evaluated using the Joanna Briggs Institute's Qualitative Research Standard Assessment tool. FINDINGS: Twenty-one studies were selected for this review. This review involved an overarching theme: The utilization of pivotal elements to transition from delayed initiation to comprehensive implementation. Three themes emerge, including the prerequisites for initiating advance care planning, not ready to start advance care planning and struggling along narrow roads. For health care professionals, the selection of an opportune moment to initiate advance care planning for people with dementia is not only a challenge but also a crucial prerequisite for the successful implementation of advance care planning. Health care professionals' experience, attitude toward advance care planning, trust relationship with patients, cultural differences among people with dementia and their caregivers, and economic disparities all influence health care professionals' judgment of the timing for initiating advance care planning. CONCLUSIONS: Determining the optimal timing for initiating advance care planning is a complex process that requires a comprehensive consideration of the realities faced by health care professionals, people with dementia and their caregivers. Therefore, it is imperative to provide relevant training to health care professionals to ensure the successful implementation of advance care planning.

Dignity-preserving care of people with dementia in different nursing environments: a qualitative systematic review.

AIMS: To systematically identify, evaluate and synthesize qualitative evidence about the dignity-related nursing experiences of people with dementia in families and nursing homes, summarize the similarities and differences and analyse the causes and influencing factors. METHODS: A synthesis of qualitative studies retrieved from eight databases that were published before September 2022. Two reviewers independently screened and selected studies. Inclusion criteria were established according to the PICOS principle. Quality assessment was guided by Joanna Briggs Institute's Qualitative Assessment and Review Instrument and the structured topic synthesis method was used to summarise studies eligible for inclusion. RESULTS: Three key themes were extracted from 14 included studies; the living environment, relationship needs and self-awareness, which focused on improving the dementia-centred nursing environment, meeting the needs of the relationship-centred nursing network, and finally, improving the self-awareness of people with dementia to promote dignity. CONCLUSION: This systematic review shows people with dementia need to integrate into society and maintain their dignity in a dementia-friendly environment that is respectful, inclusive environment that promotes freedom.

Clinical practice guidelines for the nutrition of colorectal cancer patients: a systematic review.

PURPOSE: The aim of this study is to rigorously assess the methodological quality of published clinical practice guidelines (CPGs) related to nutrition among colorectal cancer patients, to compile consensus recommendations, and to evaluate the quality of the included CPGs. METHODS: The systematic search covered eight electronic databases, two relevant professional association websites, and six guideline websites from their inception up to January 22, 2023. The methodological quality of the eligible guidelines was evaluated using the Appraisal of Guidelines Research and Evaluation II (AGREE II) instrument, and then, consensus recommendations were synthesized. The scores for each domain were expressed as the mean ± standard deviation (SD). Using the mean score as the benchmark for comparison, they were subsequently ranked from highest to lowest. The included guidelines were then categorized as having "high," "moderate," or "low" quality based on their scores. RESULTS: The literature search yielded ten guidelines. The findings indicated that the "Clarity of presentation" domain had the highest mean score (65.2 ± 7.7). This demonstrates how the guidelines effectively articulate recommendations. Additionally, the "Scope and purpose" domain achieved a mean score of 60.7 ± 10.9, followed by "Rigor of development" (51.7 ± 15.7), "Editorial independence" (51.1 ± 21), "Stakeholder involvement" (48 ± 16.8), and "Applicability" domains (47.5 ± 17.3). Two CPGs received an overall rating of "high quality" and were recommended; four CPGs received an overall rating of "moderate" and were recommended with modifications; and four CPGs received an overall rating of "low quality" and were not recommended. Furthermore, this study compiled twenty consensus recommendations related to nine distinct clinical issues. CONCLUSION: This study identified disparities in the methodological quality of the included CPGs, particularly in the "Applicability" domain, thus emphasizing the need for advancement in clinical feasibility and implementation. Notably, there is few guidelines specifically targeting colorectal cancer nutrition. These synthesized findings provided an intuitive, convenient, and comprehensive reference for evaluating nutrition among colorectal cancer patients. When applying these results, users should make careful decisions based on their specific situations.

The impact of education/training on nurses caring for patients with stroke: a scoping review.

BACKGROUND: Stroke survivors have complex needs that necessitate the expertise and skill of well-trained healthcare professionals to provide effective rehabilitation and long-term support. Limited knowledge exists regarding the availability of specialized education and training programs specifically designed for nurses caring for stroke patients. AIM: This review aims to assess the content and methods of training for nurses caring for stroke patients, examine its impact on both nurses and patients, and identify key facilitators and barriers to its implementation. METHODS: We conducted a comprehensive scoping review by reviewing multiple databases, including PubMed, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, Embase, Web of Science, Scopus, ProQuest Dissertations and Theses, Google Scholar, and Cochrane databases. Data extraction and narrative synthesis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines. RESULTS: Seventeen articles were included in this review. We found that education/training not only enhanced patients' self-care abilities, nursing outcomes, and satisfaction, but also had a positive impact on the knowledge, skills, and practices of nurses. The obstacles to education/training included feasibility and cost-effectiveness, while the driving factors were management support and participation, professional education/training, and controlled environment creation. CONCLUSIONS: This review highlights the crucial role of education/training in enhancing stroke care provided by nurses. Effective education/training integrates various educational methods and management support to overcome implementation barriers and optimize clinical practice benefits. These findings indicate the necessity of universal and consistent stroke education/training for nurses to further improve patient outcomes in stroke care.

Dynamic carboxymethyl chitosan prodrug hydrogel precisely mediates robust therapy on wound infection.

Dynamic antibacterial polysaccharide prodrug hydrogels are in great demand for treatment of wound infection owing to their unique advantages such as excellent biocompatibility, superior antimicrobial property as well as favorable wound healing capacity. Herein, this work highlights the successful development of a dynamic carboxymethyl chitosan (CMC) prodrug hydrogel, which is facilely constructed through Schiffer base reaction between antibacterial components (amikacin and CMC) and crosslinker (dialdehyde PEG). Moderate dynamic imine linkages endow the hydrogel with excellent injectable and self-healing capability as well as targeted on-demand drug release in slightly alkaline condition at infected wound. All ingredients and their strong intermolecular interactions endow the hydrogel with favorable swelling and moisture retention capability. Moreover, the covalent and non-covalent interactions also endow the hydrogel with superior adhesion and mechanical property. These attractive characteristics enable hydrogel to effectively kill pathogens, promote wound healing and reduce side effects of amikacin. Thereby, such a dynamic CMC prodrug hydrogel may open a new avenue for a robust therapy on wound infection, greatly advancing their use in clinics.

Microplastic fragmentation by rotifers in aquatic ecosystems contributes to global nanoplastic pollution.

The role of aquatic organisms in the biological fragmentation of microplastics and their contribution to global nanoplastic pollution are poorly understood. Here we present a biological fragmentation pathway that generates nanoplastics during the ingestion of microplastics by rotifers, a commonly found and globally distributed surface water zooplankton relevant for nutrient recycling. Both marine and freshwater rotifers could rapidly grind polystyrene, polyethylene and photo-aged microplastics, thus releasing smaller particulates during ingestion. Nanoindentation studies of the trophi of the rotifer chitinous mastax revealed a Young's modulus of 1.46 GPa, which was higher than the 0.79 GPa for polystyrene microparticles, suggesting a fragmentation mechanism through grinding the edges of microplastics. Marine and freshwater rotifers generated over 3.48 × 105 and 3.66 × 105 submicrometre particles per rotifer in a day, respectively, from photo-aged microplastics. Our data suggest the ubiquitous occurrence of microplastic fragmentation by different rotifer species in natural aquatic environments of both primary and secondary microplastics of various polymer compositions and provide previously unidentified insights into the fate of microplastics and the source of nanoplastics in global surface waters.

Sustainable DNA Data Storage on Cellulose Paper.

DNA is a promising material for high density and long-term archival data storage. In addition to algorithms for encoding digital information into DNA sequences, the DNA writing (chemical synthesis) and reading (DNA sequencing), the preservation of DNA mixtures with high sequence diversity is another critical issue for sustainable, long-term, and large-scale DNA data storage. Here, this work demonstrates a method for low-cost, convenient and sustainable DNA data storage on cellulose paper. A DNA pool comprising thousands of sequences, in which archival data are encoded, is conveniently stored on a cellulose paper with a calculated density as high as 15 TB per mm3 through electrostatic adsorption. This work demonstrates that these digitally encoded DNA pools can be stable for years on the cellulose paper after drying even when directly exposed to air. Furthermore, the reversible electrostatic adsorption enables repeated loading/retrieval of DNA on/off cellulose paper. Therefore, this sustainable DNA preservation on cellulose paper through the convenient electrostatic adsorption exhibits a great advantage in terms of storage capacity and cost that is crucial for practical systems to achieve large-scale and long-time data storage.

The influence of web-based decision aids on informal caregivers of people with dementia: A systematic mixed-methods review.

Caring for people with dementia is considered one of the most stressful and difficult forms of care. Informal caregivers constantly face high physical and emotional burdens. Therefore, it is essential to provide them with effective and practical support. Web-based decision aids can provide convenient and effective decision support for informal caregivers. The aim of this study was to assess and synthesize the influence of web-based decision aids on informal caregivers of people with dementia. Searches of electronic databases (CINAHL, MEDLINE, Web of Science Core Collection, Embase, PsycINFO, CNKI, Open Grey and Baidu Wenku) and reference lists of relevant studies were conducted in July 2022. Qualitative, quantitative and mixed-methods studies published in Chinese and English on the use of web-based decision aids by informal caregivers of people with dementia were included. The studies were selected by screening titles, abstracts and full texts, and the quality of each study was assessed by two researchers independently. Fourteen studies were published between 2010 and 2022, including five qualitative studies, four quantitative studies and five mixed-methods studies. Web-based decision aids have a positive influence on informal caregivers of people with dementia by providing decision support, satisfying needs, promoting psychological health, improving communication ability and reducing caregiver burden. Informal caregivers of people with dementia are receptive to web-based decision aids and expect their functionality to be optimized further. Web-based decision aids offer potential benefits to informal caregivers by providing effective decision-making support and improving their psychological health and ability to communicate.

Self-Assembly and In Situ Quaternization of Triblock Bottlebrush Block Copolymers via Organized Spontaneous Emulsification for Effective Loading of DNA.

Microspheres bearing large pores are useful in the capture and separation of biomolecules. However, pore size is typically poorly controlled, leading to disordered porous structures with limited performances. Herein, ordered porous spheres with a layer of cations on the internal surface of the nanopores are facilely fabricated in a single step for effective loading of DNA bearing negative charges. Triblock bottlebrush copolymers (BBCPs), (polynorbornene-g-polystyrene)-b-(polynorbornene-g-polyethylene oxide)-b-(polynorbornene-g-bromoethane) (PNPS-b-PNPEO-b-PNBr), are designed and synthesized for fabrication of the positively charged porous spheres through self-assembly and in situ quaternization during an organized spontaneous emulsification (OSE) process. Pore diameter as well as charge density increase with the increase of PNBr content, resulting in a significant increase of loading density from 4.79 to 22.5 ng µg-1 within the spheres. This work provides a general strategy for efficient loading and encapsulation of DNA, which may be extended to a variety of different areas for different real applications.

How to manage comorbidities in people with dementia: A scoping review.

BACKGROUND: People with dementia experience a high prevalence of comorbidities that seriously affect patient outcomes. The aim of this study was to map the evidence and components related to comorbidity management, including interventions to facilitate and support the practice of management. METHODS: A scoping review was conducted. In June 2022, PubMed, Web of Science, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), The National Institute of Health and Care Excellence (NICE), Open grey, and the Cochrane Library were searched to identify relevant literature. The inclusion criteria were outlined to identify studies on comorbidity management in people with dementia. RESULTS: We found 43 items that met the inclusion criteria. The majority of the studies were published since 2010. Most research focused on medication management, health care service use and provision, and comorbidity-related monitoring and management; there were a small number of studies that involved decision-making. Only 6 studies developed interventions to support dementia care, which included comorbidity management. Studies involving the comorbidity management process were mainly based on qualitative methods, which make it difficult to quantify the impact of these processes on comorbidity management. CONCLUSIONS: Given the serious impact of dementia on managing comorbidities, there is a need to develop systematic interventions targeting the management of comorbidities.

Polyurethane-Based Stretchable Semiconductor Nanofilms with High Intrinsic Recovery Similar to Conventional Elastomers.

Polymer semiconductors with large elastic recovery (ER) under high strain in thin film state are highly desirable for stretchable electronics. Here we report a type of stretchable semiconductor PU(DPP)x, by copolymerization of oligodiketopyrrolopyrrole-based conjugated block and hydrogenated polybutadiene flexible block via urethane linkage for intermolecular hydrogen bonding. By regulating block ratio, PU(DPP)35 with 35 wt % conjugated block exhibits high intrinsic ER > 80% under 175% strain (ε) in pseudo free-standing thin film state, comparable with commercial elastomers, and crack onset strain (COS) > 300% along with maximum hole mobility of 0.19 cm2 V-1 s-1 in organic thin film transistors to bring it to the best performing block copolymer-type stretchable semiconductors. Enhanced mobility is achieved using PU(DPP)35 as the binder for conjugated polymer PDPPT3. The 25 wt %-PDPPT3 blend displays mobility up to 1.28 cm2 V-1 s-1 along with COS ∼120%, and 10 wt %-PDPPT3 blend exhibits ER of 78% at ε = 150%, COS of ∼230%, modulus of 36.5 MPa, maximum mobility of 0.62 cm2 V-1 s-1 and no obvious degradation of mobility at ε = 150% after 100 cycles of strain. Moreover, the structural similarity enables the blend film uniform and stable microstructure against mechanical and thermal deformation. Notably, PU(DPP)35 and the blend are characterized by high mechanical performance similar to that of commercial elastomers in thin film state, and demonstrate their potential for high performance stretchable electronics.

Precise Tailoring of Polyester Bottlebrush Amphiphiles toward Eco-Friendly Photonic Pigments via Interfacial Self-Assembly.

Biodegradable photonic microspheres with structural colors are promising substitutes to polluting microbeads and toxic dyes. Here, amphiphilic polyester-block-poly(ethylene glycol) bottlebrush block copolymers (BBCPs) with polylactic acid or poly(ϵ-caprolactone) as the hydrophobic block are synthesized and used to fabricate eco-friendly photonic pigments. Molecular parameters of BBCPs, including rigidity and symmetry, are precisely tailored by variation of side chain lengths, which enables effective manipulation of interfacial tension (γ). Organized spontaneous emulsion mechanism is enabled only when γ falls in a suitable range (10.6-14.3 mN m-1 ), producing ordered water-in-oil-in-water multiple emulsions and ordered porous structures. Consequently, highly saturated and tunable structural colors are observed due to coherent light scattering from the porous structures. Such photonic materials are nontoxic as confirmed by careful safety tests using aquatic model organisms.

Interfacial Self-Assembly of Amphiphilic Core-Shell Bottlebrush Block Copolymers Toward Responsive Photonic Balls Bearing Ionic Channels.

Photonic balls can be facilely obtained through interfacial self-assembly of amphiphilic bottlebrush block polymers (BBCPs) within a water-in-oil-in-water (w/o/w) multiple emulsion system, and polystyrene (PS) has been employed as the skeleton of the balls showing no responsive properties. Here, the design and synthesis of core-shell BBCPs are demonstrated with a poly(tert-butyl acrylate)-block-polystyrene (PtBA-b-PS) block copolymer as the hydrophobic side chains and poly(ethylene glycol) as the hydrophilic block. Interfacial self-assembly of the core-shell BBCPs within shrinking droplets produces porous microspheres with full-spectrum structural colors through an organized spontaneous emulsification process. The PtBA core wrapped by PS in the skeleton of the balls can be converted into polyacrylic acid (PAA) forming an ionic channel responsive to pH variations. Consequently, the hydrolyzed photonic balls show different colors under different pH conditions dependent on varying degrees of ionization and hydration of the PAA channel. Reflected colors can be verified using an optical spectrometer, providing an effective strategy for precise pH indication.

Investigation and Analysis of Blood Biochemical Indexes and Molecular Biology of Methylmalonic Acidemia.

BACKGROUND: To compare MMA-related gene mutations in MMA children and the population in Qingdao, discuss the blood propionyl carnitine (C3), free carnitine (C0) methionine (MET), the mutual ratio and division difference in normal group, carrier group, and MMA group to analyze the relationship between some hotspot mutations and biochemical indicators. METHODS: In total 3,700 newborns testing negative in tandem mass spectrometry (MS/MS) were selected at random and submitted for testing 8 pathogenic sites in MMACHC and 10 in MMUT. The gene mutations in 84 cases with detected mutation genes and 42 diagnosed children were compared. The levels and concentration distribution of C3, C0, MET, C3/C2, C3/C0, C3/MET in the blood samples of three groups were analyzed as well as the difference of biochemical indicators in newborns with hotspot mutations (c.609A>G, c.482G>A, and c.658-660delAAG). RESULTS: All 8 pathogenic mutations in MMACHC in the population were detected and were basically consistent with the mutation types and frequency order in MMA group. The first three were c.609G>A, c.482G>A, and c.658_660delAAG. There were more types of mutation sites detected in MMA group than carrier group. Five out of 10 MMUT gene mutations were detected in the population, and 9 MMUT gene mutation sites were detected in MMA group. The findings in the two groups and the preset sites were not completely consistent. C3, C0, C3/C2, C3/C0, C3/MET in MMA group were higher than carrier and normal groups, and the difference was statistically significant; the MET in MMA group was lower than carrier and normal groups, and the difference was statistical¬ly significant. Based on the three sets of data distribution graphs, C3, C3/C2, C3/C0, and C3/MET were well distinguished. There were differences in the average C3 and C0 levels between carrier and normal groups, but with an obvious cross distribution in the graphs, and no difference in other indicators. In contrast to non-carrier group, C0, C3, C3/C0, C3/C2, and C3/MET concentration levels were higher in 609A>G mutation group, while MET level was lower, with statistical significance; in c.482G>A mutation group, C3, C3/C0, C3/C2, and C3/MET concentration levels were lower than non-carrier group, while MET level was higher, with statistical significance; in c.658-660delAAG mutation group, C0, C3, C3/C0, C3/C2, MET, and C3/MET concentration levels were not statistically different in contrast to other groups. CONCLUSIONS: The top three mutations in MMA children in Qingdao area are c.609A>G, c.482G>A, c.658-660del AAG mutations in MMAHC; C3, C3/C2, C3/C0 can be used as specific prompt indicators for MMA screening; C3, C3/C2, C3/C0, C3/MET can be used as specific prompt indicators for combined MMA screening; abnormalities in biochemical indicators in hotspot mutation group intuitively explains c.609A>G mutation and early-onset MMA. c.482G>A mutation links with late-onset MMA.

Janus Photonic Microspheres with Bridged Lamellar Structures via Droplet-Confined Block Copolymer Co-Assembly.

Artificial self-assembly systems typically exhibit limited capability in creating nature-inspired complex materials with advanced functionalities. Here, an effective co-assembly strategy is demonstrated for the facile creation of complex photonic structures with intriguing light reflections. Two different lipophilic and amphiphilic bottlebrush block copolymers (BCPs) are placed within shrinking droplets to enable a cooperative working mechanism of microphase segregation and organized spontaneous emulsification, respectively. Layer assemblies of the lipophilic BCP and uniform water nanodroplets stabilized by the bottlebrush surfactant are both generated, and co-assembled into a bridged lamellar structure with the alternating arrangement of layers and closely packed nanodroplet arrays. Janus microspheres with diverse dual optical characteristics are successfully fabricated, and reflected wavelengths of light are highly tunable simply by changing the formulation or molecular weight of BCP.

Supersoft Elastic Bottlebrush Microspheres with Stimuli-Responsive Color-Changing Properties in Brine.

Solvent-free supersoft elastomer is highly desirable for building photonic structures with significant stimuli-responsive color changes. We report supersoft elastic porous microspheres with vivid structural colors obtained via self-assembly of amphiphilic bottlebrush block copolymers at the water/oil interface templated by ordered water-in-oil-in-water double emulsions. The porous structure is composed of cross-linked bottlebrush polydimethylsiloxane (PDMS) as the supersoft elastic skeleton and bottlebrush poly(ethylene oxide) (PEO) as the internal responsive layer. The obtained microspheres show large reversible volume changes through well-controlled dehydration or hydration of PEO in response to salt ions in an aqueous environment. As a result, full-spectrum colors are obtained dependent on different salt concentrations. In-situ observation of color reflection of a microsphere indicates a gradual structural transition from the outside to the inside corresponding to migration of water molecules and salt ions. Moreover, rod-like bottlebrush PEO exhibits an anion-induced salting-out behavior different from that of random coil polymers. The significantly responsive behaviors of bottlebrush block copolymer (BBCP) assemblies in the presence of salt ions primarily rely on the supersoft elastic skeleton of the porous structure, providing a facile route to the creation of stimuli-responsive photonic materials by low-cost self-assembly methods.

Rapid Responsive Mechanochromic Photonic Pigments with Alternating Glassy-Rubbery Concentric Lamellar Nanostructures.

Photonic pigment particles prepared via self-assembly have been suffering from their poor mechanical performances; i.e., they can easily be damaged and lose structural color under a compression force. This greatly limits their uses as mechanochromic pigments. Here, a nanoscale concentric lamellar structure of alternating glassy-rubbery microdomains is successfully created within photonic microparticles through a confined self-assembly and photo-cross-linking strategy. The glassy domain is composed of polystyrene, and cross-linked bottlebrush polydimethylsiloxane served as the supersoft elastic domain. The obtained photonic structure not only shows large deformation and visible color changes under a loaded compression force but also rapidly recovers to its original state in less than 1 s (∼0.16 s) upon unloading. Continuously loading-unloading micro compression test indicates that no obvious damage can be identified after 250 cycles, indicating the high durability of the pigments against deformation. These pigments with different reflected colors are simply obtained using bottlebrush block copolymer formulations with tunable weight percentages of polymer additives. The mechanical robust photonic pigments may be useful in many important applications.

Self-Assembled Photonic Microsensors with Strong Aggregation-Induced Emission for Ultra-Trace Quantitative Detection.

Ultratrace quantitative detection based on fluorescence is highly desirable for many important applications such as environmental monitoring or disease diagnosis, which however has remained a great challenge because of limited and irregular fluorescence responses to analytes at ultralow concentrations. Herein the problem is circumvented via local enrichment and detection of analytes within a microsensor, that is, photonic porous microspheres grafted with aggregation-induced emission gens (AIEgens). The obtained microspheres exhibit dual structural and molecular functions, namely, bright structural colors and strong fluorescence. Large fluorescence quenching induced by nitrophenol compounds in an aqueous environment is observed at ultralow concentrations (10-12-10-8 mol/L), enabling quantitative detection at a ppb level (ng/L). This is achieved within a porous structure with good connectivity between the nanopores to improve analyte diffusion, an internal layer of poly(ethylene oxide) (PEO) for analyte enrichment via hydrogen bonding, and homogeneous distribution of AIEgens within the PEO layer for enhanced fluorescence quenching. The fluorescent porous microspheres can be readily obtained in a single step templated by well-ordered water-in-oil-in-water double emulsion droplets with AIE amphiphilic bottlebrush block copolymers as the effective stabilizer.