Deepened Photodynamic Therapy through Skin Optical Clearing Technology in the Visible Light Window.

The trade-off that shorter wavelength light facilitates the efficient generation of reactive oxygen species (ROS) from photosensitizer (PS) while facing the drawback of limited penetration depth through skin tissue restricts the further development of photodynamic therapy (PDT). Here, we address this contradiction and achieve visible-light-tailored deep PDT combined with the skin optical clearing technology. With the help of the prepared skin optical clearing gel, the refractive index inhomogeneity between skin tissue components is greatly attenuated, and the light scattering effect within the skin tissue is remarkably reduced. As a consequence, the transmittance of visible light at 600 nm through in vitro porcine skin and in vivo mouse skin after treatment increases from approximately 10 and 40 to 70 and 70%, respectively. Furthermore, in the tumor cell eradication experiment, the local ROS generation efficiency in the experimental group is several times higher than that in the control group owing to improved visible transmittance, which is thus responsible for the complete eradication of tumor cells, even when shaded by skin tissue. The results suggest that this strategy may serve as a valuable supplement to the current deep PDT strategies.

Superhydrophilic 2D Covalent Organic Frameworks as Broadband Absorbers for Efficient Solar Steam Generation.

The intrinsic hydrophobicity and limited light absorption especially in the near-infrared (NIR) region of porous organic polymers are two bottlenecks impeding their applications in solar steam generation (SSG). Herein, we develop a 1,4,5,8-tetrakis(phenylamino)anthracene-9,10-dione (TPAD)-based covalent organic framework (COF) (TPAD-COF) featuring both superhydrophilicity and broad light absorption covering from the entire UV/Vis to NIR regions for SSG. TPAD-COF serving as a highly efficient photothermal conversion material without any additives displays an excellent water evaporation of 1.42 kg m-2 h-1 and achieves a high energy conversion efficiency of 94 % under 1 sun irradiation. Further extension of the light absorption range of the TPAD-based COF is realized through post-synthetic modification by chelating BF2 moieties. Systematic control experiments and analysis confirm that the hydrophilicity of photothermal conversion materials plays a more dominant role in the current TPAD-based COFs for SSG.

Dark Ionic Liquid for Flexible Optoelectronics.

Owing to a wide visual angle, few aberrations, and great depth of focus, flexible optoelectronics have become one subject of intense investigation for rescue equipment and endoscopy tools. Ionic liquids are rising as a kind of fluidic "semiconductor" with advantages of high flexibility and self-healing. However, challenges in the molecular design of photoresponsive ionic liquids impede the exploration of ionic liquids as intrinsic flexible liquid optoelectronics. This work demonstrated an imidazole-based ionic liquid covalently linked with a polypyrrole oligomer by alkyl chains. Such an ionic liquid has wide absorption from the visible light range to the near-infrared light range. The imidazole moiety acts as an electrical conductor which is thermally responsive. On the other hand, the polypyrrole segment serving as a light antenna is able to convert light energy to thermal heat. The alkyl linker tailors the energy transfer between polypyrrole and an imidazole cation. Negligible molecular aggregation and phase separation are attributed to the preservation of the fluidic nature at room temperature. This photoresponsive ionic liquid is successfully exploited as a flexible light detector that is adaptable to special sensing tests in bending states.

[Study on physicochemical properties of paeonol-Helix aspersa muller nanogel and its inhibitory effects on hypertrophic scar tissue in rabbit ear].

To prepare Helix aspersa muller-paeonol nanogel( PAE-HAM-Gels) with anti-proliferative scar effect,evaluate its skin penetration,retention and irritation,and to investigate its prevention and treatment effect for hypertrophic scar in rabbit ears. The dermal retention,transdermal rate and cumulative permeability of paeonol were investigated in vitro by using the modified Franz diffusion cell and the abdominal skin of suckling pigs,SD rats and KM mice,respectively,and the in vitro permeation curves were drawn. The normal skin of the back of New Zealand rabbits was continuously treated with PAE-HAM-Gels for 7 days,and the physiological state of the skin was observed under light microscope after HE staining by using homologous left and right contrast method. The hypertrophic scar model in rabbit ears was established,and the New Zealand rabbits were randomly divided into blank group,model group,positive drug group,PAE-Gels group and PAE-HAM-Gels group. After 28 days of administration,the scar hyperplasia rate and scar elevation index( SEI) of each group were calculated; the scar tissues were taken and stained with Masson for observation of collagen fibers and muscle fibers hyperplasia under light microscope,and the expression level of TGF-ß1 in each group was detected. The Qnof PAE-HAM-Gels in aqueous solution was in line with the Higuchi equation,and its transdermal rate,cumulative permeation and dermal retention in different animal skins were all higher than those of PAE-Gels. The skin of the drug-administered group was intact,without erythema,edema or other phenomena; under light microscope,the subcutaneous tissue and the epidermal cells were neatly arranged with uniform thickness,which showed no difference from the blank group. The scar hyperplasia rate of the PAE-HAM-Gels group was 62. 50%; SEI was 2. 17±0. 33 and TGF-ß1 was( 815. 4±34. 69) ng·L~(-1),significantly different from those in model group( P<0. 01). Masson staining showed that as compared with the model group,the number of collagen fibers and muscle fibers was small and the arrangement was loose and tidy in the PAE-HAM-Gels group,with regular arrangement of chondrocytes and a small number of inflammatory cells and microvessels.PAE-HAM-Gels have good transdermal properties and dermal retention without skin irritation,offering a promising therapeutic strategy for transdermal delivery during the prevention and treatment of hypertrophic scar in rabbit ears.

[Effect of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B on proliferation,migration and cell cycle of human skin fibroblasts].

Hypertrophic scar( HS) is a very common skin fibrosis disorder after human skin injury and wound healing. The objective of this study was to investigate the efficacy of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B( SAB-TAT-LIP) on proliferation,migration and cell cycle of human skin fibroblasts( HSF),and preliminarily evaluate its effect on prevention and treatment of HS. HSF were cultured in vitro,and MTT assay was used to detect the inhibitory effect of SAB-TAT-LIP on cell proliferation. Cell migration was assessed by Transwell chamber method and scratch method; and cell cycle change was detected by flow cytometry. In vitro cell studies showed that blank liposome basically had no toxic effect on HSF. Different concentrations of SABTAT-LIP inhibited proliferation on HSF in varying degrees after intervention for different periods in a dose and time dependent manner;meanwhile,SAB-TAT-LIP significantly inhibited the migration and invasion of HSF. At the same time,SAB-TAT-LIP could block the cell cycle at G0/G1 phase after intervention for 48 h,P<0.01 as compared with the blank control group. Conclusively,our experimental data quantitatively demonstrate that SAB-TAT-LIP has significant inhibitory effect on cells proliferation,invasion and migration,with blocking effect on G0/G1 phase. This may offer a promising therapeutic strategy for transdermal delivery in prevention and treatment of HS.

A Degradable and Recyclable Photothermal Conversion Polymer.

Decomposition and repolymerization of conjugated polymers offer great promise for developing recyclable photothermal conversion materials, which yet remain challenging. Herein, a crosslinked conjugated polymer based on a dynamic covalent bond of Schiff base is developed. This polymer possesses photothermal conversion efficiency as high as 90.4 %. Decomposition of the polymer under specialized conditions is corroborated by various characterizations. The kinetics study is also investigated to understand this degradation process. Furthermore, those decomposed species can be repolymerized back to conjugated polymers which possess the same photothermal conversion efficiency as the pristine polymer. Such a degradable and recyclable photothermal polymer is successfully used as a heat source for photothermal-electrical conversion to generate Seebeck voltage under either near infrared (NIR) irradiation or solar illumination.

Formulating Polyethylene Glycol as Supramolecular Emulsifiers for One-Step Double Emulsions.

One-step double emulsions via only one-step emulsification are leading to an attractive branch of emulsion research studies owing to the ease of preparation and reduced surfactant numbers. In addition to controlling the oil/water ratio, exploiting emulsifiers with desirable amphiphilicity that can stabilize both the inner and outer water/oil interfaces is crucial to the formation of one-step double emulsions. In particular, new emulsifiers with saving laborious efforts are highly preferred in consideration of low cost and practical applications. In this work, a commonly used homopolymer, polyethylene glycol (PEG), was attempted as emulsifiers to prepare emulsions via one-step emulsification. PEG is generally considered as a hydrophilic polymer and always anchored with a hydrophobic polymer to make the copolymer amphiphilic. In the water-chloroform binary system, PEG itself exhibits amphiphilic performance and tailors the formation of single emulsions or double W/O/W emulsions on the dependence of the oil/water ratio and the PEG concentration. A possible mechanism as explained by dissipative particle dynamics simulation was proposed to demonstrate the amphiphilic feature and emulsification capability of PEG. The amphiphilicity of PEG was further tuned by interacting with iodine as a result of the formation of a supramolecular complex, which, in turn, led to the conversion from single emulsions to O/W/O double emulsions. It is believed that this line of research provides inspiration for the preparation of controllable emulsions through supramolecular routes.

Radiofrequency Thermocoagulation in Relieving Refractory Pain of Knee Osteoarthritis.

To investigate the efficacy of radiofrequency thermocoagulation (RFTC) in relieving refractory pain of knee osteoarthritis (OA), we selected 54 patients with chronic knee OA pain, 27 treated with RFTC (case group) and 27 receiving regular treatments (control group). Response evaluations were conducted before treatment, and at the termination of treatment, and 3-month follow-up, applying the visual analog scale, the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and American Knee Society Score (AKSS). Data analyses were performed with SPSS 21.0. At the termination of treatments and 3-month follow-ups, cases gained significantly increased scores in vitality, bodily pain, general health perceptions, physical functioning, and social role functioning by SF-36 scaling and in pain, range of motion, stability, walking, and stair climbing by AKSS (all P < 0.05). Controls received higher scores by AKSS in pain at the termination of treatments and in pain, range of motion, and walking at the termination of 3-month follow-ups (all P < 0.05). Both cases and controls presented significant difference between visual analog scale scores before treatments and those at the termination of 3-month follow-ups (both P < 0.05). All patients felt less pain after treatments, cases presenting better improvement (P < 0.05). Pain was stronger in females compared with males and in a positive correlation with age while had no obvious relation to disease course. In conclusion, RFTC may have better efficacy in relieving refractory pain and promoting function recovery in patients with knee OA than regular treatment.

N(2)-Selective Iodofunctionalization of Olefins with NH-1,2,3-Triazoles to provide N(2)-Alkyl-Substituted 1,2,3-Triazoles.

A new method was developed to synthesize N(2)-alkyl-substituted 1,2,3-triazole through N-iodosuccinimide (NIS) mediated iodofuctionalization reaction of the alkene group with bi-, mono-, and unsubstituted NH-1,2,3-triazoles. The favored N-1 type hydrogen bond between the iodonium ion intermediate and 1,2,3-triazole was supposed to be generated, which gave the desired N(2)-alkyl triazole with a high N(2)-selectivity.

Ultradeep Photothermal Therapy Strategies.

Photothermal therapy (PTT) mediated by the second near-infrared light (NIR-II) is considered as the most promising PTT in deep tissues due to the superior penetrability of NIR-II through biological tissues. However, the effective therapeutic depth of NIR-II mediated PTT is limited to only several millimeters beneath the skin tissues. So far, deep PTT still cannot satisfy the depth requirement for most common cancers, including but not limited to lung, pancreatic, colorectal, and stomach cancers. Therefore, it is highly desirable to develop ultradeep PTT strategies to enhance the therapeutic depth with clinical availability. This Perspective highlights the latest research progress in regard to ultradeep PTT strategies, including larger laser spot PTT, skin tissue optical clearing technology enhanced PTT, and optical fiber assisted PTT, followed with pertinent evaluations and expectations. In addition, challenges and perspectives in this fast-growing area of ultradeep PTT are discussed.

Controllable Degradation of Polyurethane Thermosets with Silaketal Linkages in Response to Weak Acid.

Polyurethane (PU) thermosets offer great favors to our daily life on account of their excellent mechanical, physical, and chemical properties as well as appreciable biocompatibility. Nevertheless, PU waste is increasingly causing environmental and health-related problems as it is mostly resistant to chemical degradation under mild conditions. Herein, we report a kind of PU thermoset with silaketal leakages in its main chains to enable polymer degradation in response to weak acids, even in edible vinegar. The degradation rate is significantly influenced by the alkyl substituents on the silicon atoms, with entire degradation in hours, days, weeks, or months. Besides controllable degradation, investigations are also provided into the recycling of PU thermosets by means of thermal reprocessing based on carbamate bond exchange or repolymerization of degradation residuals. Because of the controllable degradation and easy recycling, this particular kind of PU thermoset exhibits great potential in manufacturing green polymer products that can be decomposed by nature or reutilized after disposal.

Coupling molecular rigidity and flexibility on fused backbones for NIR-II photothermal conversion.

Great attention is being increasingly paid to photothermal conversion in the near-infrared (NIR)-II window (1000-1350 nm), where deeper tissue penetration is favored. To date, only a limited number of organic photothermal polymers and relevant theory have been exploited to direct the molecular design of polymers with highly efficient photothermal conversion, specifically in the NIR-II window. This work proposes a fused backbone structure locked via an intramolecular hydrogen bonding interaction and double bond, which favors molecular planarity and rigidity in the ground state and molecular flexibility in the excited state. Following this proposal, a particular class of NIR-II photothermal polymers are prepared. Their remarkable photothermal conversion efficiency is in good agreement with our strategy of coupling polymeric rigidity and flexibility, which accounts for the improved light absorption on going from the ground state to the excited state and nonradiative emission on going from the excited state to the ground state. It is envisioned that such a concept of coupling polymeric rigidity and flexibility will offer great inspiration for developing NIR-II photothermal polymers with the use of other chromophores.

Polydiacetylene-Polyurethane Crisscross Elastomer as an Intrinsic Shape Memory Conductive Polymer.

Owing to the high phase transition temperature and incompatibility with thermoplastic elastomers, conjugated polymers are hardly formulated as shape memory materials. This work presents a crisscross polymer composed of polyurethane and polydiacetylene. Phase separation is completely avoided based on the photoinduced polymerization of polydiacetylene from polyurethane chains. The two backbones are intercrossed and covalently linked to each other. Particularly, polyurethane acts as a soft segment to provide elastic performance, and the rigid polydiacetylene provides conductive pathways. Such a crisscross topology, combined with soft and rigid compositions, renders the possibility to serve the polymer as an intrinsically elastic conductive polymer. Intriguingly, the polymer possesses shape memory performance, meanwhile retaining the reliable conductivity. Electrical tests demonstrate that the shape memory conductive polymer is one attractive candidate for exploiting shape-customized strain sensors.

Crystal-confined freestanding ionic liquids for reconfigurable and repairable electronics.

Liquid sensors composed of ionic liquids are rising as alternatives to solid semiconductors for flexible and self-healing electronics. However, the fluidic nature may give rise to leakage problems in cases of accidental damages. Here, we proposed a liquid sensor based on a binary ionic liquid system, in which a flowing ionic liquid [OMIm]PF6 is confined by another azobenzene-containing ionic liquid crystalline [OMIm]AzoO. Those crystal components provide sufficient pinning capillary force to immobilize fluidic components, leading to a freestanding liquid-like product without the possibility of leakage. In addition to owning ultra-high temperature sensitivity, crystal-confined ionic liquids also combine the performances of both liquid and solid so that it can be stretched, bent, self-healed, and remolded. With respect to the reconfigurable property, this particular class of ionic liquids is exploited as dynamic circuits which can be spatially reorganized or automatically repaired.

Spider-Inspired Multicomponent 3D Printing Technique for Next-Generation Complex Biofabrication.

The shortage of tissue resources is currently a serious challenge that limits the clinical therapy to patients with tissue loss or end-stage organ failure. The booming development of 3D printing offers unprecedented hope for tissue engineering since it can construct cells and biomaterials into a 3D tissue-mimicking object with precise control over size and shape. However, it is still challenging to fabricate artificial living tissues or organs due to the extreme complexity of biological tissues. Herein, we propose a new concept of spider-inspired 3D printing technique (SI-3DP) for continuous multicomponent 3D printing based on in situ gelation at a multibarrel printing nozzle. The printing process allows for rapid construction of 3D architectures composed of different inks in the desired position. To present the potential in biomedical applications, the SI-DIP also prints vessel-like hollow hydrogel microfibers and cell-laden hollow fibers, indicating good biocompatibility of this technique. The newly developed SI-3DP technique is envisioned to promote the development of next-generation complex biofabrication.