Clinical Outcomes of Transaxillary Reverse-Sequence Endoscopic Nipple-Sparing Mastectomy and Direct-to-Implant Prepectoral Breast Reconstruction: A Prospective Study of Initial 68 Procedures.

BACKGROUND: Minimal access breast surgery improves cosmetic outcomes over conventional breast surgery but still faces barriers in becoming standard procedure for breast reconstruction. This report introduces a novel technique of transaxillary reverse-sequence endoscopic nipple-sparing mastectomy (R-E-NSM) followed by direct-to-implant prepectoral breast reconstruction (DTI-PBR) and describes its clinical outcomes. METHODS: This prospective study enrolled patients who underwent R-E-NSM and DTI-PBR from March 2021 to December 2021 at a single institution. Perioperative data, surgical complications, oncologic outcomes, and patient- and surgeon-reported cosmetic results were noted. RESULTS: The 60 patients in this study who underwent 68 R-E-NSM and DTI-PBR had a mean age was 40.4 ± 10.3 years. The average durations of uni- and bilateral operations were 156.5 ± 48.3 min and 191.3 ± 36.1 min, respectively. The overall surgical complication rate was 13.3%, including 10.0% of patients with minor complications and 3.3% of patients with major complications. The study had one case (1.7%) of implant loss and one case (1.7%) of skin flap necrosis treated by reoperation. During the median follow-up period of 24 months, one patient (1.7%) who discontinued chemotherapy for myelosuppression experienced liver metastases 5 months postoperatively, and one patient experienced new-onset contralateral ductal carcinoma in situ 24 months postoperatively. The preoperative and 18-month postoperative Breast-Q scores for satisfaction with breasts, psychosocial well-being, sexual well-being, and chest well-being did not differ significantly, and the Scar-Q was 81.2 ± 14.5 points. The good-to-excellent rate in surgeon-reported cosmetic results reached 90%. CONCLUSIONS: Transaxillary R-E-NSM followed by DTI-PBR is a safe and efficient technique with high cosmetic outcomes and reliable medium-term oncologic results.

Minimally Invasive and Innovative Management of Prosthesis Infections in Endoscopic-Assisted Breast Reconstruction.

BACKGROUND: Implant infection continues to be the most common complication of breast reconstruction, and it can lead to serious consequences of implant loss. Recently, endoscopic-assisted nipple-sparing mastectomy with direct-to-implant breast reconstruction is being performed more frequently, with similar prosthetic infection incidence compared to conventional techniques. But there is little information published in the literature on the management of periprosthetic infection in endoscopic-assisted breast reconstruction. METHODS: A retrospective review was performed of patients who underwent endoscope-assisted breast reconstruction and developed periprosthetic infection between January 2020 and December 2022. Prosthesis infection was defined as any case where antibiotics were given, beyond the surgeon's standard perioperative period, in response to clinical signs such as swelling, pain, erythema, increased temperature, fever, etc. We summarized our clinical approach and treatment protocol for periprosthetic infection patients. Collected data include preoperative basic information, surgical details, postoperative data, and outcomes. RESULTS: A total of 580 patients (713 reconstructions) underwent endoscopic-assisted immediate breast reconstruction. There were 58 patients developed periprosthetic infection, 14 of whom had bilateral prosthesis reconstruction with unilateral prosthesis infection. The incidence of infection was 10.0%. Average follow-up was 17.3 ± 8.9 months (range = 2-37 months). Of the 58 patients, 53 (91.4%) patients successful salvaged implant and 5(8.6%) patients removed prosthesis. During follow-up, Baker III capsular contracture occurred in 2 patients (3.8%) who had radiotherapy. CONCLUSION: Our management of prosthesis infections in endoscopic-assisted breast reconstruction is easy, minimally invasive, and inexpensive. This method can be repeated if the implant infection does not improve after the first drainage. What's more, our data suggest that our prosthesis salvage of periprosthetic infection is effective. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An Innovative and Highly Efficient Single-Port Endoscopic Nipple-/Skin-Sparing Mastectomy and Dual-Plane Direct-to-Implant Breast Reconstruction: A Prospective Study from a Single Institution.

BACKGROUND: The difficulty in creating and maintaining a stable workspace of the breast makes endoscopic nipple-/skin-spring mastectomy (E-N/SSM) develop slowly. This study aims to report the preliminary results of a novel endoscopic technique for N/SSM followed by dual-plane direct-to-implant (DP-DTI) breast reconstruction. METHODS: A prospectively maintained database was reviewed that included patients who underwent single-axillary-incision E-N/SSM and DP-DTI breast reconstruction from September 2020 to April 2021 at a single institution by three surgeons. The data were collected prospectively and analyzed to determine the efficacy, feasibility, safety, and esthetic results of the operation, as well as quality of life (QoL). RESULTS: During the study period, a total of 68 E-N/SSM and DP-DTI reconstruction procedures through a single axillary incision were performed in 63 female patients. Among all the procedures, the majority were performed for grade 1-3 ptotic breasts (n =46, 73.0%). During the median follow-up of 26.5 months, the major and minor surgical complication rates were 1.6% (1/63) and 9.5% (6/63), respectively. The cosmetic complication rate was 14.3%. One patient suffered local recurrence 4 months postoperation. The average scores in patient-reported outcomes at 2 years postoperation of satisfaction with breast (66.57), psychosocial well-being (75.93) and sexual well-being (56.29) were not significantly different compared with the baseline, except for physical well-being: chest (69.85). CONCLUSIONS: The proposed procedure for E-N/SSM and DP-DTI breast reconstruction is feasible, time-saving and safe with good outcomes in terms of cosmetic results and QoL and expands the indications of DTI reconstruction to ptotic breasts, making it easier to popularize. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Multifunctional Asymmetric Bacterial Cellulose Membrane with Enhanced Anti-Bacterial and Anti-Inflammatory Activities for Promoting Infected Wound Healing.

An asymmetric wound dressing acts as a skin-like structure serves as a protective barrier between a wound and its surroundings. It allows for the absorption of tissue fluids and the release of active substances at the wound site, thus speeding up the healing process. However, the production of such wound dressings requires the acquisition of specialized tools, expensive polymers, and solvents that contain harmful byproducts. In this study, an asymmetric bacterial cellulose (ABC) wound dressing using starch as a porogen has been developed. By incorporating silver-metal organic frameworks (Ag-MOF) and curcumin into the ABC membrane, the wound dressing gains antioxidant, reactive oxygen species (ROS) scavenging, and anti-bacterial activities. Compared to BC-based wound dressings, this dressing promotes efficient dissolution and controlled release of curcumin and silver ions. In a full-thickness skin defect model, wound dressing not only inhibits the growth of bacteria on infected wounds but also regulates the release of curcumin to reduce inflammation and promote the production of epithelium, blood vessels, and collagen. Consequently, this dressing provides superior wound treatment compared to BC-based dressing.

The Calcium Channel Inhibitor Nimodipine Shapes the Uveitogenic T Cells and Protects Mice from Experimental Autoimmune Uveitis through the p38-MAPK Signaling Pathway.

Autoimmune uveitis (AU) is a sight-threatening ocular inflammatory disorder, characterized by massive retinal vascular leakage and inflamed lesions with infiltration of the uveitogenic T cells in the retina and disorders of the T cell-related immune response in the system. Stimulation of TCRs can trigger calcium release and influx via Ca2+ channels and then transmit signals from the surface to the nucleus, which are important for energy metabolism, proliferation, activation, and differentiation. Inhibition of Ca2+ influx by pharmacological modulation of Ca2+ channels may suppress T cell function, representing a novel anti-inflammatory strategy in the treatment of AU. This study investigated the effects of the l-type voltage-gated calcium channel blocker nimodipine in experimental AU (EAU). Nimodipine was found to not only decrease the clinical and histopathological inflammation score of EAU (C57BL/6J mice) but also dwindle the infiltration of uveitogenic CD4+ T cells into the retina. Moreover, nimodipine decreased the effector T cells and increased the regulatory T cells in the immune system. In vitro, nimodipine reduced the effector T cell differentiation of the IRBP1-20-specific CD4+ T cells of EAU mice and LPS-stimulated PBMCs of uveitis patients. Meanwhile, nimodipine suppressed the energy metabolism, proliferation, activation, and Th1 cell differentiation of T cells. Further studies on RNA sequencing and molecular mechanisms have established that nimodipine alleviates EAU by regulating T cells response through the p38-MAPK pathway signaling. Taken together, our data reveal a novel therapeutic potential of the l-type Ca2+ channels antagonist nimodipine in AU by regulating the balance of T cell subsets.

Melatonin, an endogenous hormone, modulates Th17 cells via the reactive-oxygen species/TXNIP/HIF-1α axis to alleviate autoimmune uveitis.

BACKGROUND: Melatonin, an indoleamine produced by the pineal gland, plays a pivotal role in maintaining circadian rhythm homeostasis. Recently, the strong antioxidant and anti-inflammatory properties of melatonin have attracted attention of researchers. We evaluated the therapeutic efficacy of melatonin in experimental autoimmune uveitis (EAU), which is a representative animal model of human autoimmune uveitis. METHODS: EAU was induced in mice via immunization with the peptide interphotoreceptor retinoid binding protein 1-20 (IRBP1-20). Melatonin was then administered via intraperitoneal injection to induce protection against EAU. With EAU induction for 14 days, clinical and histopathological scores were graded to evaluate the disease progression. T lymphocytes accumulation and the expression of inflammatory cytokines in the retinas were assessed via flow cytometry and RT-PCR, respectively. T helper 1 (Th1), T helper 17 (Th17), and regulatory T (Treg) cells were detected via flow cytometry for both in vivo and in vitro experiments. Reactive-oxygen species (ROS) from CD4 + T cells was tested via flow cytometry. The expression of thioredoxin-interacting protein (TXNIP) and hypoxia-inducible factor 1 alpha (HIF-1α) proteins were quantified via western blot. RESULTS: Melatonin treatment resulted in notable attenuation of ocular inflammation in EAU mice, evidenced by decreasing optic disc edema, few signs of retinal vasculitis, and minimal retinal and choroidal infiltrates. Mechanistic studies revealed that melatonin restricted the proliferation of peripheral Th1 and Th17 cells by suppressing their transcription factors and potentiated Treg cells. In vitro studies corroborated that melatonin restrained the polarization of retina-specific T cells towards Th17 and Th1 cells in addition to enhancing the proportion of Treg cells. Pretreatment of retina-specific T cells with melatonin failed to induce EAU in naïve recipients. Furthermore, the ROS/ TXNIP/ HIF-1α pathway was shown to mediate the therapeutic effect of melatonin in EAU. CONCLUSIONS: Melatonin regulates autoimmune T cells by restraining effector T cells and facilitating Treg generation, indicating that melatonin could be a hopeful treatment alternative for autoimmune uveitis.

What Is the Optimal Strategy for Drain Removal After Mastectomy and Axillary Surgery in Breast Cancer Patients? A Multicenter, Three-Arm Randomized Clinical Trial.

INTRODUCTION: The best strategy for drain removal after mastectomy and axillary surgery in breast cancer patients has remained controversial. We conducted a multicenter, three-arm randomized clinical trial to determine the optimal strategy. METHODS: A total of 187 eligible breast cancer patients who underwent mastectomy and axillary surgery were randomized into 10 mL (n = 62), 20 mL (n = 63), and 30 mL (n = 63) groups for drain removal on the first day when the output decreased to a corresponding volume in 24 h. The drain duration, total drain duration, incidence of seroma, quality of life, outpatient visit times, healthcare costs, and postoperative complications were evaluated. RESULTS: The median axillary drain durations and total drain durations were all significantly different between three groups (both P < 0.001). The incidences of seroma were 31.1%, 38.3%, and 52.1%, and the difference between the 30 mL and 10 mL groups was significant (RR = 2.41). The 20 mL group reported significantly better quality of life (QoL) in terms of physical functioning (PF) at the 2-week (30 mL versus 20 mL, HR:-14.18) and 3-week (20 mL versus 10 mL, HR: 11.65) follow-up and role functioning (RF) at the 2-week follow-up (20 mL versus 10 mL, HR: 18.15). No between-group differences were found in G-QoL, outpatient visits, costs, or complications. CONCLUSIONS: The 20 mL group had a moderate drain duration, total drain duration, and incidence of seroma but a significant advantage over the other two groups in terms of PF and RF, with relatively low outpatient costs and comparable postoperative complication rates. These findings could aid in clinical decision-making regarding drain removal timing (http://www.chictr.org.cn/: ChiCTR2000028729).

Video-assisted Transaxillary Nipple-sparing Mastectomy and Immediate Implant-based Breast Reconstruction: A Novel and Promising Method.

BACKGROUND: Although video-assisted breast surgery is gaining popularity, endoscopic reconstruction after mastectomy is still facing lots of problems, bring about that endoscopic method has not yet become a standard procedure for breast cancer reconstruction. Here, we introduce a novel surgical technique of video-assisted transaxillary nipple-sparing mastectomy and immediate implant-based breast reconstruction and describe the detailed surgical procedure using this technique. METHODS: Detailed steps of surgical procedure, the patient characteristics and the mean operative time of this new technique were described in this article. All patients were asked to score their satisfaction with their reconstructed breasts preoperatively, 1 month, 3 months, 6 months and 12 months postoperatively using the BREAST-Q. RESULTS: At first, we used our "conventional method" and performed on 10 patients from April 2017 to June 2020; the operative time was 324.80 ± 66.39 minutes. After improving several procedures of the technique, the "optimized method" was performed on 14 cases from July 2020 to November 2020; the operative time decreased to 193.71 ± 28.75 minutes with shortest was 133 minutes; the optimized method was novel and easy to learn and be generalized. Most of the patients were satisfied with the reconstruction results. There was no significant difference between preoperative scores and scores at 3 months, 6 months and 12 months (p = 0.364). Since there is no wound on the breast dome, no obvious postoperative complications were observed except for one patient presented with infection. CONCLUSIONS: This new technique has allowed surgeons to achieve excellent and reproducible outcomes in a single-stage procedure and represents an excellent technique for patients who wish to have a scarless and aesthetically pleasing appearance after mastectomy for breast cancer. This article also highlights the mean operative time (193.71 ± 28.75 minutes) that has been made possible with this new technique. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

The production of bacterial cellulose in Gluconacetobacter xylinus regulated by luxR overexpression of quorum sensing system.

Quorum sensing is a mechanism that facilitates cell-to-cell communication. Through signal molecular density for signal recognition, which leads to the regulation of some physiological and biochemical functions. Gluconacetobacter xylinus CGMCC 2955, which produces bacterial cellulose (BC), synthesizes the LuxR protein belonging to the LuxI/LuxR type QS system. Here, a luxR overexpression vector was transformed into G. xylinus CGMCC 2955. The overexpression of luxR increased the yield of BC by 15.6% after 16 days static culture and reduced the cell density by 15.5% after 120-h-agitated culture. The glucose was used up by G. xylinus-pMV24-luxR at 72-h-agitated fermentation, which 12 h earlier than the wild-type (WT). The total N-acylhomoserine lactones (AHL) content of the luxR-overexpressing strain and the WT strain attained 1367.9 ± 57.86 mg/L and 842.9 ± 54.22 mg/L, respectively. The C12-HSL and C14-HSL contents of G. xylinus-pMV24-luxR were 202 ± 21.66 mg/L and 409.6 ± 0.91 mg/L, which were significantly lower than that of WT. In contrast, C6-HSL showed opposite results. The difference of AHL content proved that overexpression of luxR improved the binding of AHL and showed preference for some specific AHL. The metabolic results demonstrated that upon glucose exhaustion, the consumption of gluconic acid was promoted by luxR overexpression, and the content of D- ( +)-trehalose, an antiretrograde metabolite, increased significantly. KEY POINTS: • The overexpression of luxR increased the yield of bacterial cellulose • The content of signal molecules was significantly different • Differential metabolites were involved in multiple metabolic pathways.

Tailoring bacterial cellulose structure through CRISPR interference-mediated downregulation of galU in Komagataeibacter xylinus CGMCC 2955.

Diverse applications of bacterial cellulose (BC) have different requirements in terms of its structural characteristics. culturing Komagataeibacter xylinus CGMCC 2955, BC structure changes with alterations in oxygen tension. Here, the K. xylinus CGMCC 2955 transcriptome was analyzed under different oxygen tensions. Transcriptome and genome analysis indicated that BC structure is related to the rate of BC synthesis and cell growth, and galU is an essential gene that controls the carbon metabolic flux between the BC synthesis pathway and the pentose phosphate (PP) pathway. The CRISPR interference (CRISPRi) system was utilized in K. xylinus CGMCC 2955 to control the expression levels of galU. By overexpressing galU and interfering with different sites of galU sequences using CRISPRi, we obtained strains with varying expression levels of galU (3.20-3014.84%). By testing the characteristics of BC, we found that the porosity of BC (range: 62.99-90.66%) was negative with galU expression levels. However, the crystallinity of BC (range: 56.25-85.99%) was positive with galU expression levels; galU expression levels in engineered strains were lower than those in the control strains. Herein, we propose a new method for regulating the structure of BC to provide a theoretical basis for its application in different fields.

A prospective Study on Femoral Hernia Repair: Is the Inguinal Better Than The Infrainguinal Approach?

BACKGROUND: Femoral hernia repair has various surgical methods. However, controversy still exists regarding the best method for management. This study aimed to compare the infrainguinal with the inguinal approach in the treatment of femoral hernias. MATERIALS AND METHODS: Eighty patients with primary unilateral femoral hernias were prospectively randomized to either the infrainguinal (n = 40) or inguinal approach groups (n = 40). Patient demographics, operative time, duration of hospital stay, postoperative complications, and recurrence rate were recorded. RESULTS: There were no statistically significant differences between both study groups with respect to the patients' demographics and associated comorbidities. Regarding inpatient outcomes, there were no differences between the infrainguinal and inguinal approach groups concerning the postoperative duration of stay (P = 0.248), urinary retention (P = 0.494), superficial wound infection (P = 0.494), seroma (P = 0.615), foreign body sensation (P = 0.615), and chronic pain (P = 0.359). However, total complications were encountered in 3 patients (7.5%) in the infrainguinal approach group compared to 11 patients (27.5 %) in the inguinal approach group (P = 0.037). Also, the mean operative time was significantly shorter in the infrainguinal approach group compared to that in the inguinal group (P < 0.001). Throughout the 15 mo median follow-up duration, there was no recurrence in the inguinal approach group and one (2.5%) recurrence in the infrainguinal approach group (P = 1.000). CONCLUSIONS: In patients undergoing elective primary femoral hernia repair, the infrainguinal approach has a similar clinical curative effect to that of the inguinal approach. However, the former has the advantages of simple operation, short operation time, and fewer complications.

Applications of cellulose and chitin/chitosan derivatives and composites as antibacterial materials: current state and perspectives.

The bacterial infections have always a serious problem to public health. Scientists are developing new antibacterial materials to overcome this problem. Polysaccharides are promising biopolymers due to their diverse biological functions, low toxicity, and high biodegradability. Chitin and chitosan have antibacterial properties due to their cationic nature, while cellulose/bacterial cellulose does not possess any antibacterial activity. Moreover, the insolubility of chitin in common solvents, the poor solubility of chitosan in water, and the low mechanical properties of chitosan have restricted their biomedical applications. In order to solve these problems, chemical modifications such as quaternization, carboxymethylation, cationization, or surface modification of these polymers with different antimicrobial agents, including metal and metal oxide nanoparticles, are carried out to obtain new materials with improved physiochemical and biological properties. This mini review describes the recent progress in such derivatives and composites with potential antibacterial applications.

Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry.

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

Self-Assembled Microporous Peptide-Polysaccharide Aerogels for Oil-Water Separation.

We report a new kind of peptide-polysaccharide aerogel which was formed by the coassembly of the fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and the polysaccharide konjac glucomannan (KGM). The porosity and hydrophobicity of the hybrid aerogels could be facilely tailored by modifying the mass ratio of Fmoc-FF and KGM. The aerogels with tunable architecture showed good performance for the separation of a wide variety of oil-water mixtures. The results provide an opportunity for the design of peptide materials as a new class of biocompatible absorbents with potential applications in biomedicine and separation.

The Levels of T Lymphocyte Subsets in Immune Thrombocytopenia Associated with Anti-GPIIb/IIIa- and/or Anti-GPIbα-Mediated Responses Are Differentially Sensitive to Dexamethasone.

OBJECTIVE: The aim of this work was to investigate the influence of T lymphocyte subsets and platelet-specific autoantibodies on immune thrombocytopenia (ITP) with dexamethasone therapy. METHODS: The samples were obtained from patients before therapy. T lymphocyte subsets were measured by flow cytometry, and platelet-specific autoantibodies were evaluated by modified monoclonal antibody immobilization of platelet antigen assay. RESULTS: A total of 50 ITP patients were involved in the study. Twenty-three were anti-GPIbα antibody positive and were treated with dexamethasone, with a response rate of 47.8%. Twenty-seven cases were anti-GPIbα antibody negative, with a response rate of 77.8%. A significant difference was detected (p < 0.05). The level of CD4+ T lymphocytes in ITP patients was lower compared with the control group (p < 0.05). The level of CD8+ T lymphocytes was higher than that in the normal controls (p < 0.05). Additionally, the patients with a higher level of CD8+ T lymphocytes and lower level of CD4+ T lymphocytes were more likely to respond to dexamethasone treatment. Moreover, we observed that ITP patients associated with anti-GPIIb/IIIa antibodies had lower levels of CD4+ T lymphocytes and higher CD8+ T lymphocyte levels. CONCLUSIONS: There was insensitivity to dexamethasone treatment in ITP patients who were anti-GPIbα antibody positive. The detection of T lymphocyte subsets is useful in ITP patients for forecasting the outcome of dexamethasone treatment. There were some relationships between the different antibodies and the levels of T lymphocyte subsets.

Reconfigurable Chiral Self-Assembly of Peptides through Control of Terminal Charges.

Self-assembly of chiral nanostructures is of considerable interest, since the ability to control the chirality of these structures has direct ramifications in biology and materials science. A new approach to design chiral nanostructures from self-assembly of N-(9-fluorenylmethoxycarbonyl)-protected phenylalanine-tryptophan-lysine tripeptides is reported. The terminal charges can induce helical twisting of the assembled ß-sheets, enabling the formation of well-defined chiral nanostructures. The degree and direction of twisting in the ß-sheets can be precisely tailored through in situ pH and temperature modulations. This enables the assembly of reconfigurable chiral nanomaterials with easily adjustable size and handedness. These results offer new insight into the mechanism of helical twist formation, which may enable the precise assembly of highly dynamical materials with potential applications in biomedicine, chiroptics, and chiral sensing.

Capillary Force-Driven, Hierarchical Co-Assembly of Dandelion-Like Peptide Microstructures.

The wetting and drying of drops on flexible fibers occurs ubiquitously in nature, and the capillary force underlying this phenomenon has motivated our great interest in learning how to direct supramolecular self-assembly. Here, the hierarchical co-assembly of two aromatic peptides, diphenylalanine (FF) and ferrocene-diphenylalanine (Fc-FF), is reported via sequential, combinatorial assembly. The resulting dandelion-like microstructures have highly complex architectures, where FF microtube arrays serve as the scapes and the Fc-FF nanofibers serve as the flower heads. Homogeneous FF microtubes with diameters tailored between 1 and 9 µm and wall thickness ranging from 70 to 950 nm are initially formed by controlling the degree of supersaturation of the FF and the water content. Once the FF microtubes are formed, the growth of the dandelion-like microstructures is then driven by the capillary force, derived from the wetting and drying of the Fc-FF solution on the FF microtubes. This simple and ingenious strategy offers many opportunities to develop new and creative methods for controlling the hierarchical self-assembly of peptides and thus building highly complex nano and microstructures.

Electrostatic and aromatic interaction-directed supramolecular self-assembly of a designed Fmoc-tripeptide into helical nanoribbons.

Supramolecular self-assembly offers an efficient pathway for creating macroscopically chiral structures in biology and materials science. Here, a new peptide consisting of an N-(9-fluorenylmethoxycarbonyl) headgroup connected to an aromatic phenylalanine-tryptophan dipeptide and terminated with zwitterionic lysine (Fmoc-FWK) and its cationic form (Fmoc-FWK-NH2) were designed for self-assembly into chiral structures. It was found that the Fmoc-FWK peptide self-assembled into left-handed helical nanoribbons at pH 11.2-11.8, whereas it formed nanofibers at pH 5 and 12 and large flat ribbons composed of many nanofibers in the pH range of 6-11. However, only nanofibers were observed in the cases of Fmoc-FWK-NH2 at different values. A series of structural characterizations based on CD, FTIR, UV-vis and fluorescence spectroscopy reveal that the electrostatic and aromatic interactions and the associated hydrogen bonding direct the self-assembly into various structures. The enhanced π-π stacking and hydrogen bonding were found in the helical nanoribbons. This difference in intermolecular interactions should be derived from the ionization of carboxyl and amino groups from lysine residues at different pH values. Furthermore, we performed molecular dynamics simulations to gain insight into the assembly mechanisms. The results imply that a relatively rigid molecular conformation and the strong intramolecular aromatic interaction between Trp and Fmoc groups favor chiral self-assembly. This study is the first attempt to design a Fmoc-tripeptide for the fabrication of helical structures with macroscopic chirality, which provides a successful example and allows us to create new peptide-based chiral assembly systems.