Dual-rotor strategy for organic cocrystals with enhanced near-infrared photothermal conversion.

Organic cocrystal engineering provides a promising route to promote the near-infrared (NIR) light harvesting and photothermal conversion (PTC) abilities of small organic molecules through the rich noncovalent bond interactions of D/A units. Besides, the single-bond rotatable groups known as "rotors" are considered to be conducive to the nonradiative transitions of the excited states of organic molecules. Herein, we propose a single-/double-bond dual-rotor strategy to construct D-A cocrystals for NIR PTC application. The results reveal that the cocrystal exhibits an ultra-broadband absorption from 300 nm to 2000 nm profiting from the strong π-π stacking and charge transfer interactions, and the weakened p-π interaction. More importantly, the PTC efficiency of cocrystals at 1064 nm in the NIR-II region can be largely enhanced by modulating the number of rotor groups and the F-substituents of D/A units. As is revealed by fs-TA spectroscopy, the superior NIR PTC performance can be attributed to the nonradiative decays of excited states induced by the free rotation of the single-bond rotor (-CH3) from the donors and the inactive double-bond rotor ([double bond, length as m-dash]C(C[triple bond, length as m-dash]N)2) being in the active form of [-C(C[triple bond, length as m-dash]N)2] in the excited states from the acceptors. This prototype displays a promising route to extend the functionalization of small organic molecules based on organic cocrystal engineering.

Anion-Counterion Strategy toward Organic Cocrystal Engineering for Near-Infrared Photothermal Conversion and Solar-Driven Water Evaporation.

An anion-counterion strategy is proposed to construct organic mono-radical charge-transfer cocrystals for near-infrared photothermal conversion and solar-driven water evaporation. Ionic compounds with halogen anions as the counterions serve as electron donors, providing the necessary electrons for efficient charge transfer with unchanged skeleton atoms and structures as well as the broad red-shifted absorption (200-2000 nm) and unprecedented photothermal conversion efficiency (~90.5 %@808 nm) for the cocrystals. Based on these cocrystals, an excellent solar-driven interfacial water evaporation rate up to 6.1±1.1 kg ⋅ m-2 ⋅ h-1 under 1 sun is recorded due to the comprehensive evaporation effect from the cocrystal loading in polyurethane foams and chimney addition, such performance is superior to the reported results on charge-transfer cocrystals or other materials for solar-driven interfacial evaporation. This prototype exhibits the great potential of cocrystals prepared by the one-step mechanochemistry method in practical large-scale seawater desalination applications.

Prevalence and risk factors of subsyndromal delirium among postoperative patients: A systematic review and meta-analysis.

AIM: The aim of this study is to determine the prevalence and risk factors for subsyndromal delirium in the postoperative patient. DESIGN: A systematic review and meta-analysis. METHODS: The Review Manager 5.3 statistics platform and the Newcastle-Ottawa Scale were used for quality evaluation. DATA SOURCES: The following databases were searched: PubMed, Web of Science, EMBASE, The Cochrane Library, Scopus and EBSCO from January 2000 to December 2021. Additional sources were found by looking at relevant articles' citations. RESULTS: A total of 1744 titles were originally identified, and five studies including 962 patients were included in the systematic review, with a pooled prevalence of postoperative subsyndromal delirium (PSSD) of 30% (95% CI: 0.28-0.32). Significant risk variables for PSSD were older age, low levels of education (≤9 years), cognitive impairment, higher comorbidity score, and the duration of operation. CONCLUSION: PSSD is prevalent and is associated with a variety of risk factors as well as low academic performance. IMPACT: Identification and clinical management of patients with PSSD should be improved. Future research on PSSD risk factors should look at a wider range of intraoperative and postoperative risk factors that can be changed. PATIENT AND PUBLIC CONTRIBUTION: No Patient or Public Contribution.

Primary Structural Units "D+A-" Ion Pairs Dominating Near-Infrared Photothermal Conversion of Organic Ionic Cocrystals.

The specific stacking mode of D/A blocks is often considered to largely determine the physicochemical properties of cocrystals. However, this rule may fail when encountering a large degree of (integer or near-integer) charge transfer situations. Herein, we explore the extensive correlations between the possible smallest structural units, stacking modes, and near-infrared photothermal conversion (NIR-PTC) properties of F4TCNQ-based cocrystals with typical features of integer-charge-transfer. Surprisingly, these cocrystals with distinct stacking modes display analogous D-A interactions, broad red-shift absorption, ultrafast (1-3 ps) relaxation dynamics of excited states, and excellent NIR-PTC properties. This supports that the resulting "D+A-" ion pairs from integer-charge-transfer may serve as the primary structural units beneath the secondary stacking modes to dominate the property of cocrystals. The stacking modes play an important but only secondary role. This work provides new insights into the structure-dynamics-property correlations and modular design of organic cocrystals for PTC and other applications.

Somatic acupressure for the fatigue-sleep disturbance-depression symptom cluster in breast cancer survivors: A phase II randomized controlled trial.

OBJECTIVE: To evaluate the feasibility of the somatic acupressure (SA) for managing the fatigue-sleep disturbance-depression symptom cluster (FSDSC) among breast cancer (BC) survivors and its preliminary effects. METHODS: In this Phase II randomized controlled trial (RCT), 51 participants were randomised evenly into the true SA group, sham SA group, and usual care group. All the participants received usual care. The two SA groups performed additional true or sham self-acupressure daily for seven weeks. The primary outcomes related to the assessment of participants' recruitment and compliance with study questionnaires and interventions. Clinical outcomes assessed the preliminary effects of SA on fatigue, sleep disturbance, depression, and quality of life. Semi-structured interviews were undertaken to capture participants' experiences of participating in this study. The statistical effects of the intervention on the outcomes were modelled in repeated measures ANOVA and adjusted generalized estimating equations. RESULTS: Forty-five participants completed the SA intervention. No adverse events were reported. Over 85% of the participants could sustain for 25 days or more and 15 min or more per session, but the adherence to the intervention requirement was yet to improve. The group by time effect of the FSDSC and depression were significant (p < 0.05). Qualitative findings showed that participants positively viewed SA as a beneficial strategy for symptom management. CONCLUSIONS: The SA intervention protocol and the trial procedures were feasible. The results demonstrated signs of improvements in targeted outcomes, and a full-scale RCT is warranted to validate the effects of SA on the FSDSC.

Mechanochemistry toward Organic "Salt" via Integer-Charge-Transfer Cocrystal Strategy for Rapid, Efficient, and Scalable Near-Infrared Photothermal Conversion.

Invited for this month's cover is the group of Shun-Li Chen and Ming-De Li at the Shantou University. The image shows that one electron can be transferred easily from donor to acceptor unit to obtain integer-charge-transfer cocrystals for realizing high-efficient solar-harvesting and photothermal conversion. The Research Article itself is available at 10.1002/cssc.202300644.

The Transport of Charged Molecules across Three Lipid Membranes Investigated with Second Harmonic Generation.

Subtle variations in the structure and composition of lipid membranes can have a profound impact on their transport of functional molecules and relevant cell functions. Here, we present a comparison of the permeability of bilayers composed of three lipids: cardiolipin, DOPG (1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), and POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol)). The adsorption and cross-membrane transport of a charged molecule, D289 (4-(4-diethylaminostyry)-1-methyl-pyridinium iodide), on vesicles composed of the three lipids were monitored by second harmonic generation (SHG) scattering from the vesicle surface. It is revealed that structural mismatching between the saturated and unsaturated alkane chains in POPG leads to relatively loose packing structure in the lipid bilayers, thus providing better permeability compared to unsaturated lipid bilayers (DOPG). This mismatching also weakens the efficiency of cholesterol in rigidifying the lipid bilayers. It is also revealed that the bilayer structure is somewhat disturbed by the surface curvature in small unilamellar vesicles (SUVs) composed of POPG and the conical structured cardiolipin. Such subtle information on the relationship between the lipid structure and the molecular transport capability of the bilayers may provide clues for drug development and other medical and biological studies.

Mechanochemistry toward Organic "Salt" via Integer-Charge-Transfer Cocrystal Strategy for Rapid, Efficient, and Scalable Near-Infrared Photothermal Conversion.

Inspired by the concept of ionic charge-transfer complexes for the Mott insulator, integer-charge-transfer (integer-CT) cocrystals are designed for NIR photo-thermal conversion (PTC). With amino-styryl-pyridinium dyes and F4TCNQ (7,7',8,8'-Tetracyano-2,3,5,6-tetrafluoroquinodimethane) serving as donor/acceptor (D/A) units, integer-CT cocrystals, including amorphous stacking "salt" and segregated stacking "ionic crystal", are synthesized by mechanochemistry and solution method, respectively. Surprisingly, the integer-CT cocrystals are self-assembled only through multiple D-A hydrogen bonds (C-H⋅⋅⋅X (X=N, F)). Strong charge-transfer interactions in cocrystals contribute to the strong light-harvesting ability at 200-1500 nm. Under 808 nm laser illumination, both the "salt" and "ionic crystal" display excellent PTC efficiency beneficial from ultrafast (∼2 ps) nonradiative decay of excited states. Thus integer-CT cocrystals are potential candidates for rapid, efficient, and scalable PTC platforms. Especially amorphous "salt" with good photo/thermal stability is highly desirable in practical large-scale solar-harvesting/conversion applications in water environment. This work verifies the validity of the integer-CT cocrystal strategy, and charts a promising path to synthesize amorphous PTC materials by mechanochemical method in one-step.

Ultrafast excited-state energy dissipation pathway of diethylamino hydroxybenzoyl hexyl benzoate (DHHB) via the nanoparticles.

The organic UVA filter is popularized in sunscreen cosmetics due to the advantages of excellent light stability and high molar extinction coefficient. However, the poor water solubility of organic UV filters has been a common problem. Given that nanoparticles (NPs) can significantly improve the water solubility of organic chemicals. Meanwhile, the excited-state relaxation pathways of NPs might differ from their solution. Here, the NPs of diethylamino hydroxybenzoyl hexyl benzoate (DHHB), a popular organic UVA filter, were prepared by an advanced ultrasonic micro-flow reactor. The surfactant (sodium dodecyl sulfate) was selected as an effective stabilizer to prevent the self-aggregation of the NPs for DHHB. Femtosecond transient ultrafast spectroscopy (fs-TA) and theoretical calculations were utilized to trace and explain the excited-state evolution of DHHB in NPs suspension and its solution. The results reveal that the surfactant-stabilized NPs of DHHB reserve a similarly good performance of ultrafast excited-state relaxation. The stability characterization experiments demonstrate that the strategy of surfactant-stabilized NPs for sunscreen chemicals can maintain its stability and enhance the water solubility of DHHB compared with that of the solution phase. Therefore, the surfactant-stabilized NPs of organic UV filters are an effective method to improve water solubility and keep the stability from aggregation and photoexcitation.

Smart antimicrobial Pickering emulsion stabilized by pH-responsive cellulose-based nanoparticles.

Responsive antimicrobial materials can control and slow the release of antimicrobial agents smartly by responding to the stimulation of environmental conditions. In this study, we designed the pH-responsive cellulose-based nanoparticles (TOCNC-g-PEI) with amino and carboxyl groups by grafting polyethyleneimine (PEI) to carboxylated cellulose nanocrystals. Finally, the Pickering emulsion was endowed with smart antimicrobial properties by emulsifying the oregano essential oil (OEO) with nanoparticles. The TOCNC-g-PEI25000 had uniform size, greater dispersion, and excellent antimicrobial properties. The contact angles of nanoparticles were 78.70 ± 1.13°, 55.80 ± 1.58° and 55.35 ± 1.56° at neutral conditions, pH 4.0 and 8.0, respectively. The nanoparticles were responding to pH stimulation. The developed emulsion (4:6, 1.30 wt%) had exceptionally stabilized and encapsulated 98.56 ± 1.22 % of the oil phase. The OEO released rapidly within 0-12 h and slowly at 12-36 h. The cumulative release rates quickly reached 93.60 ± 3.73 % (pH 4.0) and 83.25 ± 0.36 % (pH 8.0) and stabilized gradually. The antimicrobial rates of emulsion stimulated for 4 h reached 100 % at pH 4.0, and both of them exceeded 96.10 ± 2.49 % at pH 8.0. The response of Pickering emulsion to pH stimulating controlled release antimicrobial agents and achieved smart antimicrobial.

Necrostatin-1 prevents skeletal muscle ischemia reperfusion injury by regulating Bok-mediated apoptosis.

BACKGROUND: Receptor interacting serine/threonine kinase 1 (RIPK1) mediates apoptosis by regulating the classic proapoptotic effectors Bcl-2-associated X protein (Bax) and Bcl-2 homologous antagonist/killer (Bak). Although Bcl-2-related ovarian killer (Bok) is structurally similar to Bak and Bax, it is unclear whether it mediates apoptosis in skeletal muscle ischemia reperfusion (IR) injury. We hypothesized that by regulating Bok-mediated apoptosis, inhibiting RIPK1 with necrostatin-1 would reduce skeletal muscle IR injury. METHODS: Rats were randomized into four groups: sham (SM), IR, IR treated with necrostatin-1 (NI), or vehicle dimethyl sulfoxide (DI). For the IR group, the right femoral artery was clamped for 4 hours and then reperfused for 4 hours, and for the NI and DI groups, necrostatin-1 (1.65 mg/kg) and the equal volume of dimethyl sulfoxide were intraperitoneally administered prior to IR induction. The structural damage of muscle tissue and protein expression of Bok, Bcl-2, and cleaved caspase-3 were investigated, and apoptotic cells were identified with terminal dUTP nick-end labeling (TUNEL) staining. In vitro, human skeletal muscle cells (HSMCs) were exposed to 6 hours of oxygen-glucose deprivation followed by normoxia for 6 hours to establish an oxygen-glucose deprivation/reoxygenation (OGD/R) model. To determine the role of Bok, cell viability, lactate dehydrogenase (LDH) release, and flow cytometry were examined to demonstrate the effects of necrostatin-1 and Bok knockdown on the OGD/R insult of HSMCs. RESULTS: Necrostatin-1 pretreatment markedly reduced IR-induced muscle damage and RIPK1, Bok, and cleaved caspase-3 expression, whereas upregualted Bcl-2 expression (p < 0.05). Furthermore, necrostatin-1 prevented mitochondrial damage and decreased TUNEL-positive muscle cells (p < 0.05). In vitro, HSMCs treated with necrostatin-1 showed reduced Bok expression, increased cell viability, and reduced LDH release in response to OGD/R (p < 0.05), and Bok knockdown significantly blunted the OGD/R insult in HSMCs. CONCLUSION: Necrostatin-1 prevents skeletal muscle from IR injury by regulating Bok-mediated apoptosis.

Probing catalytic reduction on the surface of Au nanoparticles by second-harmonic generation and two-photon luminescence.

The catalytic reduction of aromatic nitro compounds by metallic nanoparticles in the presence of sodium borohydride (NaBH4) has been widely studied as model reactions. However, the reaction mechanisms still need further investigations. For example, the origin of the induction time that has often been observed is still controversial. Here, we demonstrated that such catalytic reduction reactions on the surface of colloidal gold nanoparticles (AuNPs) may be inspected by the second-harmonic generation (SHG) and two-photon luminescence (TPL) emission from AuNPs. It was revealed that the SHG and TPL signals from AuNPs were sensitive to the substitution of citrate by active hydride species derived from the hydrolysis of NaBH4. Based on the UV-vis spectroscopy analyses and monitoring the SHG/TPL signals, the induction time in the catalytic reaction of 4-nitrothiophenol was revealed to originate from the hindered adsorption of hydride on the gold surface. This work demonstrated that SHG and TPL can provide a new approach for detecting active hydrides on the surface of metallic nanoparticles in colloids.

The effect of an evidence-based Tai chi intervention on the fatigue-sleep disturbance-depression symptom cluster in breast cancer patients: A preliminary randomised controlled trial.

PURPOSE: To explore the potential effects of Tai chi on the fatigue-sleep disturbance-depression symptom cluster (FSDSC) among breast cancer (BC) patients. METHODS: This study was conducted as a preliminary randomized controlled trial among 72 BC patients (36 Tai chi and 36 control participants). All the participants were provided with routine care, while participants in the Tai chi group received an additional 8-week Tai chi intervention. Participants' fatigue, sleep disturbance and depression were assessed by the Brief Fatigue Inventory, the Pittsburgh Sleep Quality Index, and the Hospital Anxiety and Depression Scale-Depression. Participants' quality of life (QoL) was assessed by the Functional Assessment of Cancer Therapy-Breast. Both covariates-unadjusted and adjusted GEE models were run to assess the effects of Tai chi intervention on the FSDSC and QoL and the relevant impacts of the covariates. RESULTS: Sixty-nine participants completed this study. In the unadjusted GEE model, compared with the control group and baseline, participants in the Tai chi group showed significant reductions in fatigue (p < 0.001), sleep disturbance (p < 0.001) and depression (p = 0.006), as well as a significant improvement in QoL (p = 0.032) at immediately post-intervention and four-week follow-up. The positive regression coefficients of the adjusted GEE model showed fatigue, sleep disturbance and depression can have impacts on each other (all at p < 0.05). CONCLUSION: Tai chi as an adjuvant intervention to routine care could relieve the symptom cluster of fatigue, sleep disturbance and depression and improve QoL among BC patients.

The Emerging Role of Immune Cells and Targeted Therapeutic Strategies in Diabetic Wounds Healing.

Poor wound healing in individuals with diabetes has long plagued clinicians, and immune cells play key roles in the inflammation, proliferation and remodeling that occur in wound healing. When skin integrity is damaged, immune cells migrate to the wound bed through the actions of chemokines and jointly restore tissue homeostasis and barrier function by exerting their respective biological functions. An imbalance of immune cells often leads to ineffective and disordered inflammatory responses. Due to the maladjusted microenvironment, the wound is unable to smoothly transition to the proliferation and remodeling stage, causing it to develop into a chronic refractory wound. However, chronic refractory wounds consistently lead to negative outcomes, such as long treatment cycles, high hospitalization rates, high medical costs, high disability rates, high mortality rates, and many adverse consequences. Therefore, strategies that promote the rational distribution and coordinated development of immune cells during wound healing are very important for the treatment of diabetic wounds (DW). Here, we explored the following aspects by performing a literature review: 1) the current situation of DW and an introduction to the biological functions of immune cells; 2) the role of immune cells in DW; and 3) existing (or undeveloped) therapies targeting immune cells to promote wound healing to provide new ideas for basic research, clinical treatment and nursing of DW.

Near-Infrared Light Triggered a High Temperature Utilizing Donor-Acceptor Cocrystals.

Developing a suitable initiation for the energetic materials that respond to a low-power near-infrared laser can aid in replacing the current expensive and bulky laser-initiation systems. Here, we report on a system of molecularly tailored 1:1 donor-acceptor (D-A) charge-transfer (CT) cocrystals that manifest ultrabroad absorption (200-2500 nm) characteristics as well as noteworthy very fast self-assembly behaviors. The very narrow highest occupied molecular orbital-lowest unoccupied molecular orbital gap enables N,N,N',N'-tetramethyl-p-phenylenediamine and tetrahalo-1,4-benzoquinones (TMPD-TXBQ) cocrystals to have a great light-harvesting ability in the near-infrared range. When irradiated with a low-power hand-held 808 nm laser with an input energy of only 40 mJ or a power density of 260 mW·cm-2, these TMPD-TXBQ cocrystals immediately undergo an efficient photothermal conversion followed by a dramatic exothermic thermal polymerization reaction due to the face-to-face D-A-D-A stacking in these cocystals to achieve a temperature as high as 318.9 °C. This temperature is high enough for a thermal initiation of most common energetic materials, and thus this TMPD-TXBQ cocrystal can potentially act as a near-infrared laser initiator that is compact, lightweight, and cost-effective.

[Features of intestinal flora in children with food protein-induced proctocolitis based on high-throughput sequencing]. / åŸºäºŽé«˜é€šé‡æµ‹åºæŠ€æœ¯åˆ†æžé£Ÿç‰©è›‹ç™½è¯±å¯¼æ€§ç›´è‚ ç»“è‚ ç‚Žæ‚£å„¿è‚ é“èŒç¾¤ç‰¹å¾.

OBJECTIVES: To study the features of intestinal flora in children with food protein-induced proctocolitis (FPIP) by high-throughput sequencing. METHODS: A total of 31 children, aged <6 months, who experienced FPIP after exclusive breastfeeding and attended the outpatient service of the Third Affiliated Hospital of Zunyi Medical University from October 2018 to February 2021 were enrolled as the FPIP group. Thirty-one healthy infants were enrolled as the control group. Fecal samples were collected to extract DNA for PCR amplification. High-throughput sequencing was used to perform a bioinformatics analysis of 16S rDNA V3-V4 fragments in fecal samples. RESULTS: The diversity analysis of intestinal flora showed that compared with the control group, the FPIP group had a lower Shannon index for diversity (P>0.05) and a significantly higher Chao index for abundance (P<0.01). At the phylum level, the intestinal flora in both groups were composed of Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Compared with the control group, the FPIP group had a significant reduction in the composition ratio of Actinobacteria (P<0.001) and a significant increase in the composition ratio of Proteobacteria (P<0.05). At the genus level, the intestinal flora in the FPIP group were mainly composed of Escherichia, Clostridium, Enterococcus, Klebsiella, and Bifidobacterium, and the intestinal flora in the control group were mainly composed of Bifidobacterium and Streptococcus. Compared with the control group, the FPIP group had a significant reduction in the composition ratio of Bifidobacterium and Ruminococcus (P<0.05) and significant increases in the composition ratios of Clostridium and Shigella (P<0.05). CONCLUSIONS: Compared with the control group, the FPIP group has a reduction in the diversity of intestinal flora and an increase in their abundance, and there are certain differences in several bacterial genera. These results suggest that changes in the composition of intestinal flora at genus level may play an important role in the development and progression of FPIP.

Boosting Near-Infrared Photothermal Conversion by Intermolecular Interactions in Isomeric Cocrystals.

Organic cocrystal exhibits excellent photothermal conversion (PTC), but how the intermolecular interactions of cocrystals regulate the PTC is obscure. Here, two isomeric donor molecules (phenanthrene and anthracene) and two electron-withdrawing molecules (7,7,8,8,8-tetracyanodimethylquinone and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethane) are self-assembled into the four cocrystals (PTQ, PFQ, ATQ, and AFQ). By changing the molecular configuration of the donor and the electron-withdrawing ability of the acceptor, the intrinsic influencing factors of the intermolecular interaction on the PTC were explored. Under near-infrared laser (808 nm) irradiation, the PTC efficiencies of PTQ, PFQ, AFQ, and ATQ are 35.85, 44.74, 57.00, and 60.53%, respectively. Based on the single-crystal X-ray diffraction, ultrafast time-resolved transient absorption, and excited-state theoretical calculations, we found that the π-π stacking in ATQ and AFQ is conducive to promoting the near-infrared light-harvesting ability and the p-π interaction of cocrystals can regulate the nonradiative rotation of -C(C≡N)2 groups, resulting in a tunable near-infrared PTC via the isomeric cocrystals. Accordingly, the evaporation rate of the porous polyurethane-AFQ foam can reach 1.33 kg·m-2·h-1 in the simulated solar-driven water evaporation system. This work provides a strategy to boost the PTC by the intermolecular interactions of cocrystal materials.

Ultrafast study of substituted-position-dependent excited-state evolution in benzophenone-carbazole dyads.

Donor and acceptor (D-A) compounds based on benzophenone (BP) and carbazole (Cz) were recently reported to exhibit an extraordinary long afterglow phosphorescence in the solid state. However, the BP derivatives' mechanism of long afterglow phosphorescence is obscure. BP-o-Cz, BP-m-Cz, and BP-p-Cz were designed by coupling Cz at the ortho-, meta- and para-positions of the BP's benzene ring to uncover the excited-state evolution of BP-Cz molecules. Femtosecond and nanosecond transient absorption and excited-state theoretical calculations were carried out to detect and trace the photophysical process of BP-Cz dyads. After the excitation, all dyads experience intramolecular charge transfer (ICT) and intersystem crossing (ISC) processes. The resulting charge-transfer (1CT and 3CT) state of BP-o-Cz will decay to the ground state directly and quickly via the fast charge recombination (CR) process, which may be caused by through-space D-A interaction due to the enforced proximity between BP and Cz. In contrast, for BP-m-Cz and BP-p-Cz dyads, the complete separation of HOMOs and LUMOs leads to extended ICT and slow CR processes, producing an obvious Cz cation radical intermediate and an ultralong-lived triplet state species after the 3CT. Herein, we demonstrated that the excited-state evolution channels could be modified by tuning the substituted positions of D-A dyads. This may pave the way for designing efficient D-A type luminescent materials.

Understanding the different cross-membrane transport kinetics of two charged molecules on the DOPG lipid surface with second harmonic generation and MD simulation.

A clear physical picture of the dynamic behavior of molecules on the surface of the lipid membrane is highly desired and has attracted great attention from researchers. In this study, a step forward in this direction based on previous studies was presented with second harmonic generation (SHG) and molecular dynamic (MD) simulation. Specifically, details on the orientation flipping and cross-membrane transport of two charged molecules, 4-(4-diethylaminostyry)-1-methyl-pyridinium iodide (D289) and malachite green (MG), on the surface of 2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG) lipids were presented. Firstly, the orientation flipping of the two molecules on the surface of lipids before their cross-membrane transport was confirmed by the MD simulation. Then, the concentration dependent rate of the cross membrane transport for MG/D289 was analyzed. It was found that a simplified model could satisfactorily interpret the faster cross-membrane transport of MG under higher bulk concentrations. A different concentration dependent dynamics was observed with D289 and the reason behind it was also discussed. With this investigation, the surface structures and dynamics of D289 and MG on the DOPG lipid surface were clearly presented.

Revealing the mechanisms of vesicle formation with multiple spectral methods.

The investigation of the self-assembly of amphiphilic molecules and the formation of micelles/vesicles has attracted significant attention. However, in situ and real-time methods for such studies are rare. Here, a surface-sensitive second harmonic generation (SHG) technique was applied to study the formation of vesicles in solutions of an anti-cancer drug, doxorubicin (DOX), and a generally used surfactant (sodium bis (2-ethylhexyl) sulfosuccinate, AOT). With the aid of two-photon fluorescence (TPF), Rayleigh scattering and TEM, we revealed the structural evolution of the aggregated micelles/vesicles. It was found that AOT and DOX molecules rapidly aggregated and formed micelles in the solution. The residual DOX then acted as a "glue" that induced the aggregating/growing of the micelles and the transformation from aggregates to vesicles. The existence of lipid films, which was considered as the necessary intermediate state for vesicle formation, was excluded via the SHG observations, indicating that hollow shells may be directly transformed from solid aggregated micelles in the self-assembly formation of complex vesicles. The combined spectroscopic methods were also used to investigate the formation of vesicles from a commonly used lipid (i.e., 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt, DOPG) from its stacked bilayers. The swelling, curving and sealing of the DOPG bilayers for vesicle formation was monitored and clear dynamics were revealed. This work shows that the vesicle formation mechanism varies with the initial state of the surfactant/lipid molecules. It not only demonstrates the capability of the combined spectroscopic methods in investigating the aggregated systems but also provides new insight for understanding the formation of vesicles.