Interpenetrating Polymer Network HA/Alg-RGD Hydrogel: An Equilibrium of Macroscopic Stability and Microscopic Adaptability for 3D Cell Growth and Vascularization.

Two-dimensional (2D) cell culture methods dominate the current research. However, the inherent responsiveness of cells to their native three-dimensional (3D) microenvironment necessitates a paradigm shift toward the development of advanced hydrogels that faithfully mimic the intricacies of the extracellular matrix (ECM) and enable continuous cell-ECM interactions. To address the constraints of traditional static hydrogel networks that impede effective cell-matrix and cell-cell interactions, and to tackle the inherent stability issues associated with dynamically cross-linked hydrogels, which have become a pressing concern. Herein, we present an interpenetrating polymer network (IPN) hydrogel (HA/Alg-RGD hydrogel) that combines a physically cross-linked network between alginate and calcium ions (Alg-Ca2+) for the enhanced cell growth adaptability with a chemically cross-linked hyaluronic acid (HA) network to ensure macroscopic stability during cell culture. The incorporation of arginine-glycine-aspartic peptide modified alginate (Alg-RGD) further facilitates cell adhesion and improves the cell-hydrogel interaction. Notably, this IPN hydrogel demonstrates mechanical stability and enables cell spreading and growth within its structural framework. Leveraging the reversible characteristics of the ionically cross-linked Alg-Ca2+ network within IPN hydrogels, we demonstrate the feasibility of the gelatin sacrificial solution for 3D printing purposes within the hydrogel matrix. Subsequent UV-induced covalent cross-linking enables the fabrication of vascularized microfluidic channels within the resulting construct. Our results demonstrate endothelial cell spreading and spontaneous cell sprouting within the hydrogel matrix, thus highlighting the efficacy of this IPN hydrogel system in facilitating 3D cell growth. Additionally, our study emphasizes the potential of 3D printed constructs as a promising approach for vascularization in tissue engineering. The importance of RGD peptides in promoting favorable cell-hydrogel scaffold interactions is also highlighted, emphasizing their critical role in optimizing biomaterial-cell interfaces.

MMP-Responsive Nanoparticle-Loaded, Injectable, Adhesive, Self-Healing Hydrogel Wound Dressing Based on Dynamic Covalent Bonds.

Developing a multifunctional hydrogel wound dressing with good injectability, self-healing, tissue adhesion, biocompatibility, and fast skin wound healing efficiency remains challenging. In this work, an injectable adhesive dopamine-functionalized oxidized hyaluronic acid/carboxymethyl chitosan/collagen (AHADA/CCS/Col) hydrogel was constructed. The Schiff dynamic bond between AHADA and CCS, the N-Ag-N bond between CCS and Ag ions, and the S-Ag-S dynamic bond between sulfhydryl-modified collagen (ColSH) and Ag ions allowed the hydrogel to be both injectable and self-healing. Moreover, the aldehyde groups and catechol groups presented in the hydrogel could generate force with several groups on the tissue interface; therefore, the hydrogel also had good tissue adhesion. In vitro experiments proved that this hydrogel exhibited good biocompatibility and could promote cell proliferation. Additionally, curcumin (Cur)-loaded gelatin nanoparticles (Cur@Gel NPs) were prepared, which could respond to matrix metalloproteinases (MMPs) and controllably release Cur to hasten wound healing efficiency. Animal experiment results showed that this AHADA/CCS/Col hydrogel loaded with Cur@Gel NPs promoted wound repairing better, indicating its potential as a wound dressing.

OH planar laser-induced fluorescence imaging system using a kilohertz-rate 283 nm UV Ti:sapphire laser.

A narrow linewidth Ti:sapphire laser is developed and characterized for the generation of an ultraviolet nanosecond laser pulses for the planar laser-induced fluorescence (PLIF) imaging of hydroxyl (OH). With a pump power of 11.4 W at 1 kHz, the Ti:sapphire laser produces 3.5 mJ at 849 nm with pulse duration of 17 ns and achieves a conversion efficiency of 28.2%. Accordingly, its third-harmonic generation outputs 0.56 mJ at 283 nm in BBO with type I phase match. An OH PLIF imaging system has been built; a 1 to 4 kHz fluorescent image of OH of a propane Bunsen burner has been captured based on this laser system.

In Situ Forming Cellulose Nanofibril-Reinforced Hyaluronic Acid Hydrogel for Cartilage Regeneration.

Hyaluronic acid (HA) based hydrogels are one of most functional natural biomaterials in the field of cartilage tissue engineering (CTE). Even with the promising advantages of HA hydrogels, the complicated mechanical properties of the native cartilage have not been realized, and fabricating HA hydrogels with excellent mechanical properties to make them practical in CTE still remains a current challenge. Here, a strategy that integrates hydrogels and nanomaterials is shown to form a HA hydrogel with sufficient mechanical loading for cartilage tissue production and recombination. Cellulose nanofibrils (CNFs) are promising nanomaterial candidates as they possess high mechanical strength and excellent biocompatibility. In this study, we developed methacrylate-functionalized CNFs that are able to photo-crosslink with methacrylated HA to fabricate HA/CNF nanocomposite hydrogels. The present composite hydrogels with a compressive modulus of 0.46 ± 0.05 MPa showed adequate compressive strength (0.198 ± 0.009 MPa) and restorability, which can be expected to employ as a stress-bearing tissue such as articular cartilage. Besides, this nanocomposite hydrogel could provide a good microenvironment for bone marrow mesenchymal stem cell proliferation, as well as chondrogenic differentiation, and exhibit prominent repair effect in the full-thickness cartilage defect model of SD rats. These results suggest that the HA/CNF nanocomposite hydrogel creates a new possibility for fabricating a scaffold in CTE.

Endovascular hypothermia improves post-resuscitation myocardial dysfunction by increasing mitochondrial biogenesis in a pig model of cardiac arrest.

The aim of the study was to investigate the effects of endovascular hypothermia on mitochondrial biogenesis in a pig model of prolonged cardiac arrest (CA). Ventricular fibrillation was electrically induced, and animals were left untreated for 10 min; then after 6min of cardiopulmonary resuscitation (CPR), defibrillation was attempted. 25 animals that were successfully resuscitated were randomized into three groups: Sham group (SG, 5, no CA), normal temperature group (NTG, 5 for 12 h observation and 5 for 24 h observation), and endovascular hypothermia group (EHG, 5 for 12 h observation and 5 for 24 h observation). The core temperatures (Tc) in the EHG were maintained at 34 ±â€¯0.5 °C for 6 h by an endovascular hypothermia device (Coolgard 3000), then actively increased at the speed of 0.5 °C per hour during the next 6 h to achieve a normal body temperature, while Tc were maintained at 37.5 ±â€¯0.5 °C in the NTG. Cardiac and mitochondrial functions, the quantification of myocardial mitochondrial DNA (mtDNA), peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), nuclear respiratory factor (NRF)-1, and NRF-2 were examined. Results showed that myocardial and mitochondrial injury and dysfunction increased significantly at 12 h and 24 h after CA. Endovascular hypothermia offered a method to rapidly achieve the target temperature and provide stable target temperature management (TTM). Cardiac outcomes were improved and myocardial injuries were alleviated with endovascular hypothermia. Compared with NTG, endovascular hypothermia significantly increased mitochondrial activity and biogenesis by amplifying mitochondrial biogenesis factors' expressions, including PGC-1α, NRF-1, and NRF-2. In conclusions, endovascular hypothermia after CA alleviated myocardial and mitochondrial dysfunction, and was associated with increasing mitochondrial biogenesis.

L-band mode-locked femtosecond fiber laser with gigahertz repetition rate.

We demonstrate an L-band passively mode-locked femtosecond fiber laser with a fundamental repetition rate of 1.013 GHz based on a semiconductor saturable absorber mirror. Compared with other reported L-band fiber lasers that use overlong Er-doped fiber, the laser here consists of 10 cm heavily doped fiber to increase the fundamental pulse repetition rate to gigahertz level. An output ratio as low as 0.2% is used to make the central wavelength up to 1.6 µm. The laser operates at the soliton regime with a 3 dB spectral bandwidth of 13.6 nm and a pulse duration of 229 fs.

Compact low-noise passively mode-locked Er-doped femtosecond all-fiber laser with 2.68 GHz fundamental repetition rate.

A passively mode-locked Er-doped fiber laser with a fundamental repetition rate of 2.68 GHz is reported. The oscillator operating at a central wavelength of 1558.35 nm has a compact, robust structure and low-noise performance. The timing jitter integrated from 30 MHz down to 300 Hz is 82.5 fs, and the timing jitter performance is analyzed based on the theory model. The amplification and compression of the high repetition rate optical pulses are also investigated. After a three-stage amplifier, the average power is boosted to 430 mW. Meanwhile, based on the nonlinear self-phase modulation effect, the spectral bandwidth is broadened from 7.56 to 19.2 nm, and the corresponding pulse width is compressed to 244 fs.

Robust soliton crystals in a thermally controlled microresonator.

We demonstrate robust soliton crystals generation with a fixed frequency pump laser through a thermoelectric-cooler-based thermal-tuning approach in a butterfly-packaged complementary-metal-oxide-semiconductor-compatible microresonator. Varieties of soliton crystal states, exhibiting "palm-like" optical spectra that result from the strong interactions between the dense soliton ensembles and reflect their temporal distribution directly, are experimentally observed by sweeping one cavity resonance across the pump frequency from the blue-detuned side by reducing the operating temperature of the resonator. Benefitting from the tiny intra-cavity energy change, repeatable interconversion between the chaotic modulation instability and stable soliton crystal states can be successfully achieved via simple tuning of the temperature or pump power, showing the easy accessibility and excellent stability of such soliton crystals. This work could facilitate microresonator-based optical frequency combs towards a portable, adjustable, and low-cost system while avoiding the requirements of delicate frequency-sweeping pump techniques.

CPR feedback/prompt device improves the quality of hands-only CPR performed in manikin by laypersons following the 2015 AHA guidelines.

PURPOSE: We investigated the effects of a cardiopulmonary resuscitation (CPR) feedback/prompt device on the quality of chest compression (CC) during hands-only CPR following the 2015 AHA guidelines. METHODS: A total of 124 laypersons were randomly assigned into three groups. The first (n=42) followed the 2010 guidelines, the second (n=42) followed the 2015 guidelines with no feedback/prompt device, the third (n=40) followed the 2015 guidelines with a feedback/prompt device (2015F). Participants underwent manual CPR training and took a written basic life support examination, then required to perform 2min of hands-only CPR monitored by a CPR feedback/prompt device. The quality of CPR was quantified as the percentage of correct CCs (mean CC depth and rate, complete recoil and chest compression fraction (CCF)) per 20s, as recorded by the CPR feedback/prompt device. RESULTS: Significantly higher correct ratios of CC, CC depth, and rate were achieved in the 2010 group in each minute vs the 2015 group. The greater mean CC depth and rate were observed in the 2015F group vs the 2015 group. The correct ratio of CC was significantly higher in the 2015F group vs the 2015 group. CCF was also significantly higher in the 2015F group vs the 2015 group in the last 20s of CPR. CONCLUSIONS: It is difficult for a large percentage of laypersons to achieve the targets of CC depth and rate following the 2015 AHA guidelines. CPR feedback/prompt devices significantly improve the quality of hands-only CPR performance by laypersons following the standards of the 2015 AHA guidelines.

34-fs, all-fiber all-polarization-maintaining single-mode pulse nonlinear amplifier.

We present an all-fiber all-polarization-maintaining (PM) single mode (SM) fiber pulse nonlinear amplification system. The seed laser with a repetition rate of 200 MHz is amplified by two-section erbium-doped PM gain fibers with different peak-absorption rate. The amplified pulse duration can be compressed into 34-fs with 320-mW output power, which corresponds to 1.6-nJ pulse energy and approximate 23.5-kW peak power. In addition, the amplified and compressed pulse is further coupled into the high nonlinear fiber and an octave-spanning supercontinuum generation can be obtained. To the best of our knowledge, it is the highest peak power and the shortest pulse duration obtained in the field of all-fiber all-PM SM pulse-amplification systems.

Environmental-adaptability analysis of an all polarization-maintaining fiber-based optical frequency comb.

We demonstrate an all polarization-maintaining (PM) fiber-based optical frequency comb and provide the detailed environmental stability analysis results. The frequency comb has been built by commercial available PM fiber completely, and its static uncertainty in optical domain is 350 Hz in 1 s when referenced to a low noise oven controlled crystal oscillator. The acoustic resonant frequencies of the system have been measured. It is proved that acoustic-vibration induced phase noise could be eliminated by low pass vibration-isolation structure. Further, the existence of the optimum working temperature is illustrated. At this temperature (289.6 K), the out-loop integrated phase noise of f(r) and the temperature-drift induced instability of f(CEO) reach the lowest level 31.6 µrad and 0 kHz/(mW∙K) respectively. Finally, the system is proved to be stable under different humidity (18% ~80%) by a 240-day-long record of the f(CEO).

Spatiotemporal evolution of a cosine-modulated stationary field and Kerr frequency comb generation in a microresonator.

Based on the normalized spatiotemporal Lugiato-Lefever equation, the evolutions of cosine-modulated stationary fields relating to the generation of single-free spectral range (FSR) or multi-FSR Kerr frequency combs in a microresonator with anomalous dispersion are studied numerically. The research results show that a single-FSR comb arises when a dissipative soliton pulse or multiple nonequidistant soliton pulses form in the cavity. Compared with the smooth and regular spectral structure of a single soliton pulse, the comb corresponding to the uneven distribution of multiple soliton pulses exhibits a complex and irregular profile. When the stable intracavity field consists of a "roll" Turing pattern or N(N>1) evenly distributed soliton pulses separated by 2π/N, multi-FSR combs can be generated. In the case of the "roll" Turing pattern solution, it is found that third-order dispersion could modify the comb mode spacing and decrease the intensity of high-order comb modes. For the situation of multiple soliton pulse generation, the simulation results indicate that both the number and locations of the soliton pulses can be actively controlled through the careful selection of modulation frequency. In addition, for the selected cosine-modulated initial field profile, only those modes with the mode numbers being equal to an integer multiple of N can be greatly amplified by the parametric gain during propagation in the microresonator. This process eventually leads to the formation of a N-FSR frequency comb.

Compression-only cardiopulmonary resuscitation vs standard cardiopulmonary resuscitation: an updated meta-analysis of observational studies.

OBJECTIVES: To perform an updated meta-analysis of observational studies with unstratified cohort addressing whether compression-only cardiopulmonary resuscitation (CPR), compared with standard CPR, improves outcomes in adult patients with out-of-hospital cardiac arrest and a subgroup meta-analysis for the patients with cardiac etiology arrest. METHODS: We searched the relevant literature from MEDLINE and EMBASE databases. The baseline information and outcome data (survival to hospital discharge, favorable neurologic outcome at hospital discharge, and return of spontaneous circulation on hospital arrival) were extracted both in an out-of-hospital cardiac arrest and cardiac origin arrest subgroup. Meta-analyses were performed by using Review Manager 5.0. RESULTS: Eight studies involving 92,033 patients were eligible. Overall meta-analysis showed that standard CPR was associated with statistically improved survival to hospital discharge (risk ratio [RR], 0.95 [95% confidence interval, 0.91-0.99]) and return of spontaneous circulation on hospital arrival (RR, 0.95 [95% confidence interval, 0.92-0.99]) compared with compression-only CPR, but there is no significant difference in favorable neurologic outcome at hospital discharge between 2 CPR methods (RR, 0.97 [95% confidence interval, 0.91-1.04]). In the subgroup of patients with a cardiac cause of arrest, the pooled meta-analysis found compression-only CPR resulted in the similar survival to hospital discharge as standard CPR (RR, 0.99 [95% confidence interval, 0.94-1.05]). CONCLUSIONS: This meta-analysis found that compression-only CPR resulted in the similar survival rate as the standard CPR in the cardiac etiology subgroup. It is unclear for the patients with noncardiac cause of arrest and with long periods of untreated arrest.

An acoustic method (Spectral Flux) to analyze ECG signals for optimizing timing for defibrillation in a porcine model of ventricular fibrillation.

Aim: Spectral Flux (SF), which is based on common algorithms in the audio processing field, was applied to quantitatively analyze ECG signals to optimize the timing of defibrillation. With the aim of proving the performance in optimizing the timing of defibrillation, SF was compared with Amplitude Spectrum Area (AMSA) in a porcine model of ventricular fibrillation (VF) in a retrospective analysis experiment. Methods: A total of 56 male domestic pigs, weighing 40 ± 5 kg, were induced to undergo VF. Animals were then left untreated for 10 min, and after 6 min of cardiopulmonary resuscitation (CPR) defibrillation was performed. The respective SF and AMSA values were calculated every minute during VF and CPR. Comparisons were made through receiver operating characteristic (ROC) curves, one-way analyses of variance (one-way ANOVA), and scatterplots for the successful initial defibrillation sample (positive samples, Group R) and the failed initial defibrillation sample (negative samples, Group N) to illustrate the performance in optimizing the timing of defibrillation for the AMSA and SF methods. Result: Values of SF and AMSA gradually decreased during the 10 min VF period and increased in during the 6 min CPR period. The scatterplots showed that both metrics had the ability to distinguish positive and negative samples (p < .001). Meanwhile, ROC curves showed that SF (area under the curve, AUC = 0.798, p < .001) had the same ability as AMSA (AUC = 0.737, p < .001) to predict the successful defibrillation (Z = 1.35, p = 0.177). Moreover, when comparing the values for AMSA and SF between the successful initial defibrillation samples (Group R) and the failed initial defibrillation samples (Group N), the results showed that the values of both AMSA and SF in Group R were significantly higher than those in Group N (p < .001). Conclusion: In the present study, SF method had the same ability as AMSA to predict successful defibrillation with significantly higher values in cases of successful defibrillation than the instances in which defibrillation failed. Additionally, SF method might be more stable than AMSA for filtering out the higher frequency interference signals due to the narrower frequency range and had higher specificity and predictive accuracy than AMSA. So SF method had high clinical potential to optimize the timing of defibrillation. Nevertheless, further animal and clinical studies are still needed to confirm the effectiveness and practicality of SF as a predictive module for defibrillators in clinical practice.

An Injectable Hydrogel Composing Anti-Inflammatory and Osteogenic Therapy toward Bone Erosions Microenvironment Remodeling in Rheumatoid Arthritis.

Healing bone erosions in rheumatoid arthritis (RA) remains greatly challenging via biomaterial strategies. Given the unsuccessful innate bone erosion healing due to an inflammatory disorder, over-activated osteoclasts, and impaired osteoblasts differentiation, RA pathogenesis-guided engineering of an innovative hydrogel platform is needed for remodeling osteoimmune and osteogenic microenvironment of bone erosion healing. Herein, in situ adaptable and injectable interpenetrating polymer network (IPN) hydrogel is developed through an ingenious combination of a bio-orthogonal reaction between hyaluronic acid (HA) and collagen, along with effective electrostatic interactions leveraging bisphosphonate (BP)-functionalized HA macromers (HABP) and nanorod shaped zinc (Zn)-doped biphasic calcium phosphate (ZnBCP). IPN hydrogel exhibits exceptional adaptability to the local shape complexity at bone erosions, and by integrating ZnBCP and HABP, a multi-stage releasing platform is engineered, facilitating controlled cargo delivery for remodeling more anti-inflammatory M2 cells and reducing over-activated osteoclastic activities, thereby reconstructing the bone regeneration microenvironment. Sustainedly co-delivering multiple ions (calcium and phosphate) can display excellent osteogenic properties and be conducive to the bone formation process, by effects of osteogenesis-associated cell differentiation. Overall, the introduced bioactive IPN hydrogel therapy remodels the osteoimmune environment by synergistic pro-inflammation-resolving, osteogenesis, and anti-osteoclastic activities, displaying excellent bone reconstruction in the collagen-induced arthritis rabbit model.

Construction of adhesive and bioactive silk fibroin hydrogel for treatment of spinal cord injury.

Spinal cord injury (SCI) often causes severe and permanent disabilities due to the complexity of injury progression. The promising methods are generally based on tissue engineering technology using biocompatible hydrogels to achieve SCI repair. However, hydrogels are commonly incapable of close contact with the damaged spinal cord stumps and fail to support neural regeneration in SCI. Therefore, it is still a challenge to achieve stable contact with the transected nerve stumps and accelerate neural regeneration in the lesion microenvironment. Here, an in situ forming glycidyl methacrylated silk fibroin/ laminin-acrylate (SF-GMA/LM-AC) hydrogel was fabricated for SCI repair. The polymer chains formed a network quickly after ultraviolet (UV)-light trigger, in topological entanglement with the spinal cord, stitching the hydrogel and wet tissues together like a suture at the molecular scale. The SF-GMA/LM-AC hydrogel also provided a favorable environment for the growth of cells due to the incorporation of LM-AC. Compared with physical entrapment of LM, LM-AC immobilized in the hydrogel by covalent technology provided better microenvironments for neural stem cells (NSCs) growth. The repair of complete transection SCI in rats demonstrated that this hydrogel guided and promoted neural regeneration over 8 weeks, leading to hind limb locomotion recovery. This adhesive and bioactive SF-GMA/LM-AC hydrogel may open many opportunities in various therapeutic indications, including SCI. STATEMENT OF SIGNIFICANCE: Many materials have been developed for building transplanted scaffolds, but it is still a challenge to fabricate bioactive scaffolds and adhesion to wet tissues. In this study, we successfully developed an in situ forming SF-GMA/LM-AC hydrogel for SCI repair. This in situ forming hydrogel formed significant adhesion to the native spinal cord, stitching hydrogel and tissue together like a suture at the molecular scale. In addition, covalent immobilized LM-AC was used as the contact guidance biochemical cues for axonal outgrowth and had much better bioactive effects than physically entangled LM. Moreover, this universal strategy would open an avenue to fabricate adhesive and bioactive hydrogel for various disease treatments including SCI.

Mussel bioinspired, silver-coated and insulin-loaded mesoporous polydopamine nanoparticles reinforced hyaluronate-based fibrous hydrogel for potential diabetic wound healing.

Diabetes wounds take longer to heal due to extended inflammation, decreased angiogenesis, bacterial infection, and oxidative stress. These factors underscore the need for biocompatible and multifunctional dressings with appropriate physicochemical and swelling properties to accelerate wound healing. Herein, insulin (Ins)-loaded, and silver (Ag) coated mesoporous polydopamine (mPD) nanoparticles were synthesized (Ag@Ins-mPD). The nanoparticles were dispersed into polycaprolactone/methacrylated hyaluronate aldehyde dispersion, electrospun to form nanofibers, and then photochemically crosslinked to form a fibrous hydrogel. The nanoparticle, fibrous hydrogel, and nanoparticle-reinforced fibrous hydrogel were characterized for their morphological, mechanical, physicochemical, swelling, drug-release, antibacterial, antioxidant, and cytocompatibility properties. The diabetic wound reconstruction potential of nanoparticle-reinforced fibrous hydrogel was studied using BALB/c mice. The results indicated that Ins-mPD acted as a reductant to synthesize Ag nanoparticles on their surface, held antibacterial and antioxidant potential, and their mesoporous properties are crucial for insulin loading and sustained release. The nanoparticle-reinforced scaffolds were uniform in architecture, porous, mechanically stable, showed good swelling, and possessed superior antibacterial, and cell-responsive properties. Furthermore, the designed fibrous hydrogel scaffold demonstrated good angiogenic, anti-inflammatory, increased collagen deposition, and faster wound repair capabilities, therefore, it could be used as a potential candidate for diabetic wound treatment.

Nonlinear Absorption Response of Zirconium Carbide Films.

Zirconium carbide (ZrC), a novel representative of the MXene family, has attracted considerable interest because of its outstanding physicochemical properties and potential applications in optoelectronic devices. For improving its performance as an optical modulator for ultrashort lasers, there is a call to continue studying the nonlinear optical behavior of MXene ZrC. Herein, for the first time, MXene ZrC films were fabricated on fused silica by magnetron sputtering deposition technology and used as a saturable absorber (SA) optical modulator in a passive Q-switched Nd:YAG laser. The saturation absorption behaviors of the prepared ZrC films were characterized by the Z-scan method. Their morphology, band structure, damage threshold, carrier recovery time, and saturation absorption properties were analyzed. The experimental results show that the MXene ZrC SA films exhibit excellent nonlinear optical characteristics, with a saturation intensity of 48.4 MW/cm2, a large modulation depth of 6.9%, and an ultrashort recovery time of 2.72 ps. In addition, the damage threshold of MXene ZrC SA films was estimated to be greater than 0.2516 J/cm2. By integrating the ZrC SA film optical modulator into the oscillator of the Nd:YAG laser, we achieved stable operation of the Q-switched laser with a central wavelength at 1.06 µm, with the shortest pulse width of 78 ns. The results of this study demonstrate the potential use of MXene ZrC SA films as optical modulators in ultrashort lasers.

Multifaceted tannin crosslinked bioinspired dECM decorated nanofibers modulating cell-scaffold biointerface for tympanic membrane perforation bioengineering.

Tympanic membrane (TM) perforation leads to persistent otitis media, conductive deafness, and affects life quality. Ointment medication may not be sufficient to treat TM perforation (TMP) due to the lack of an underlying tissue matrix and thus requiring a scaffold-based application. The engineering of scaffold biointerface close to the matrix via tissue-specific decellularized extracellular matrix (dECM) is crucial in instructing cell behaviour and regulating cell-material interaction in the bioengineering domain. Herein, polycaprolactone (PCL) and TM-dECM (from Sprague-Dawley rats) were combined in a different ratio in nanofibrous form using an electrospinning process and crosslinked via tannic acid. The histological and biochemical assays demonstrated that chemical and enzymatic decellularization steps removed cellular/immunogenic contents while retaining collagen and glycosaminoglycan. The morphological, physicochemical, thermomechanical, contact angle, and surface chemical studies demonstrated that the tannin crosslinked PCL/dECM nanofibers fine-tune biophysical and biochemical properties. The multifaceted crosslinked nanofibers hold the tunable distribution of dECM moieties, assembled into a spool-shaped membrane, and could easily insert into perforated sites. The dECM decorated fibers provide a preferable biomimetic matrix for L929 fibroblast adhesion, proliferation, matrix adsorption, and f-actin saturation, which could be crucial for bioengineering. Overall, dECM patterning, surface hydrophilicity, interconnected microporosities, and multifaceted nanofibrous biosystem modulate cell-scaffold performance and could open opportunities to reconstruct TMP in a biomimetic fashion.

Injectable thioketal-containing hydrogel dressing accelerates skin wound healing with the incorporation of reactive oxygen species scavenging and growth factor release.

Wound healing is a complex dynamic process. During the occurrence of skin injury, the excessive reactive oxygen species (ROS) level is associated with sustained inflammatory response, which limits efficient wound repair. Although multifunctional hydrogels are considered ideal wound dressings due to their unique advantages, the development of hydrogel dressings with rapid gelling rates, shape adaptation, and antioxidant function is still a vital challenge. In this work, a ROS-responsive injectable polyethylene glycol hydrogel containing thioketal bonds (PEG-TK hydrogel) was synthesized and utilized to deliver epidermal growth factor (EGF). We adopted bio-orthogonal click chemistry for crosslinking the polymer chains to obtain the EGF@PEG-TK hydrogel with fast gelation time, injectability and shape-adaptability. More interestingly, the thioketal bonds in the PEG-TK hydrogel not only scavenged excessive ROS in the wound sites but also achieved responsive and controlled EGF release to facilitate regeneration. The EGF@PEG-TK hydrogel treatment offered the benefits of protecting cells from oxidative stress, accelerating wound closure, and reducing scar formation in the full-thickness skin defect model. This work provides a promising strategy for developing antioxidant hydrogel dressing for facilitating the repair of wounds.