Integrated GelMA and interleukin 8-loaded liposome composite scaffold for endogenous BMSCs recruitment in bone repair.

Bone repair strategies, based on endogenous stem cell recruitment, can effectively avoid immune rejection and the low utilization of exogenous stem cells. Endogenous stem cells can be recruited to the implantation site by loading chemokines onto bone tissue-engineered scaffolds. However, challenges such as unstable chemokine activity and easy inactivation after implantation remain significant. In the present study, composite fiber scaffolds ((IL8@LIP)-GelMA) consisting of Interleukin 8 (IL8) -loaded liposomes and GelMA were constructed by electrospinning and photocrosslinking, and its ability to recruit bone marrow-derived mesenchymal stem cells (BMSCs) and immunomodulatory effect was investigated. Compared to GelMA loaded directly with IL8, scaffolds of (IL8@LIP)-GelMA demonstrated superior protection of IL8 activity, ensuring a slow and continuous release. Both in vivo and in vitro experiments demonstrated that the (IL8@LIP)-GelMA scaffolds effectively recruited BMSCs to the desired sites. Additionally, the (IL8@LIP)-GelMA scaffolds exhibited the capacity to recruit more macrophages to the implantation site. Importantly, they promoted the polarization of macrophages toward the M2 anti-inflammatory phenotype, facilitating the transition from the inflammatory stage to the tissue repair stage. Therefore, (IL8@LIP)-GelMA scaffolds show great potential for cell-free tissue engineering applications and provide insights into the loading mode of growth factors in scaffolds.

Self-assembly of hydrazide-linked porous organic polymers rich in titanium for efficient enrichment of glycopeptides and phosphopeptides from human serum.

In this work, titanium-rich hydrazide-linked porous organic polymers (hydrazide-POPs-Ti4+) were synthesized using hydrazine, 2,3-dihydroxyterephthalaldehyde (DHTA) and trimethyl 1,3,5-benzenetricarboxylate (TP) as the ligands. Hydrazide-POPs-Ti4+ combined with HILIC and IMAC can be used for simultaneous enrichment of glycopeptides and phosphopeptides. The detection limit of this protocol is 0.1 fmol µL-1 for glycopeptides and 0.005 fmol µL-1 for phosphopeptides, and the selectivities are 1 : 1000 and 1 : 2000 for glycopeptides and phosphopeptides, respectively. For practical bio-sample analysis, 201 glycopeptides associated with 129 glycoproteins and 26 phosphopeptides associated with 21 phosphoproteins were selectively captured from healthy human serum, and 186 glycopeptides associated with 117 glycoproteins and 60 phosphopeptides associated with 50 phosphoproteins were enriched in the serum of breast cancer patients. Gene Ontology analysis indicated that the identified glycoproteins and phosphoproteins were linked to breast cancer, including the binding of complement component C1q and low-density lipoprotein particles, protein oxidation and complement activation, suggesting that these connected pathways are probably engaged in the disease pathology of breast cancer.

Engineering oleaginous yeast Yarrowia lipolytica for enhanced limonene production from xylose and lignocellulosic hydrolysate.

Limonene, a valuable cyclic monoterpene, has been broadly studied in recent decades due to its wide application in the food, cosmetics and pharmaceutical industries. Engineering of the yeast Yarrowia lipolytica for fermentation of renewable biomass lignocellulosic hydrolysate may reduce the cost and improve the economics of bioconversion for the production of limonene. The aim of this study was to engineer Y. lipolytica to produce limonene from xylose and low-cost lignocellulosic feedstock. The heterologous genes XR and XDH and native gene XK encoding xylose assimilation enzymes, along with the heterologous genes tNDPS1 and tLS encoding orthogonal limonene biosynthetic enzymes, were introduced into the Po1f strain to facilitate xylose fermentation to limonene. The initially developed strain produced 0.44 mg/L of limonene in 72 h with 20 g/L of xylose. Overexpression of genes from the mevalonate pathway, including HMG1 and ERG12, significantly increased limonene production from xylose to ∼9.00 mg/L in 72 h. Furthermore, limonene production peaked at 20.57 mg/L with 50% hydrolysate after 72 h when detoxified lignocellulosic hydrolysate was used. This study is the first to report limonene production by yeast from lignocellulosic feedstock, and these results indicate the initial steps toward economical and sustainable production of isoprenoids from renewable biomass by engineered Y. lipolytica.

Colloidal photonic crystal array chip based on nanoparticle self-assembly on patterned hydrophobic surface for signal-enhanced fluorescent assay of adenosine.

A controllable approach for preparing a portable colloidal photonic crystal (CPC) array chip is presented. The approach was inspired by the confinement effect of nanoparticle self-assembly on patterned surface. Hydrophobic polydimethylsiloxane substrate with reproducible micro-region array was fabricated by soft-lithography. The substrate was employed as the patterned template for self-assembly of monodisperse polystyrene nanoparticles. The CPC units can be prepared in several minutes, and exhibit consistent reflection wavelength. By adjusting the size of polystyrene nanoparticles and the shape of micro-regions, CPC units with multiple structure, colors and geometries were obtained. The CPC array chip features fluorescence enhancement owing to the optical modulation capability of the periodic nanostructure of the self-assembled CPC. With the reflection wavelength (523 nm) of green CPC units overlapping the emission wavelength (520 nm, with excitation wavelength of 490 nm) of 6-carboxyfluorescein-labeled DNA probe, the fluorescence intensity increased more than 10-fold. For signal-amplified assay of adenosine, the concentration range of linear response was 5.0 × 10-5 mol L-1 to 1.0 × 10-3 mol L-1, and the limit of detection was 1.3 × 10-6 mol L-1. Because of the enhancement effect of photonic crystal, the fluorescence images were more readable from the CPC array chip, compared with those from the planar substrate. The chip has potential applications in multiplex determination with high-throughput via encoding strategy based on the tunable structure, color or geometric shape. Graphical abstractSchematic diagram of signal-enhanced fluorescent detection of adenosine based on the colloidal photonic crystal array chip (PDMS, polydimethylsiloxane; PS NPs, polystyrene nanoparticles; CPC, colloidal photonic crystal; GO, graphene oxide; FAM, 6-carboxyfluorescein).

Audiological features in congenital bony atresia of external auditory canal with temporal-mandibular joint retroposition.

OBJECTIVES: To facilitate the diagnosis, treatment and surgical options for congenital bony atresia of external auditory canal (EAC) with temporal-mandibular joint (TMJ) retroposition by analyzing its audiological features and the morphology of temporal bone on CT scan. MATERIALS AND METHODS: Two cohorts of patients with congenital EAC bony atresia with (n=23) or without (n=21) TMJ retroposition were recruited from September 2012 to July 2014 at Beijing Tongren Hospital, Capital Medical University. The patients with TMJ retroposition were set as the group A and those without as group B. Based on the degree of TMJ retroposition, group A was further divided into two sub-groups A1 (n=13) and A2 (n=10). The temporal bone CT scan, pure tone average (PTA) and air-bone gap (ABG) were obtained for the main outcome measurements. SPSS 17.0 was used for the statistics analysis with t and t test. RESULTS: For group A, the average air conduction (AC) was 55.22±12.53dBHL, the average bone conduction (BC) was 7.07±3.34dBHL, and the average ABG was 50.69±8.60dBHL. For the sub-groups A1 and A2, the average AC was respectively 45.77±8.43dBHL and 59.50±7.43dBHL, BC 7.07±3.34dBHL and 6.89±4.37dBHL, and ABG 47.31±7.92dBHL and 53.00±7.91dBHL. For group B, the average AC was 70.24±5.63dBHL, BC 6.78±4.37dBHL, and ABG 60.19±6.09dBHL. CONCLUSIONS: The degree of TMJ retroposition is negatively related to the severity of hearing loss among patients with congenital EAC bony atresia, and those with TMJ have suffered less severe hearing loss than those without. Although TMJ retroposition might be a disadvantage for patients undergoing EAC plasty and tympanoplasty, it must be considered for its influence on hearing loss severity and auditory canal abnormality when planning the surgical treatment. Different from normal surgical protocol for congenital EAC bony atresia, we commend other hearing reconstruction methods such as BAHA and VSB, even without intervention.

Morphogenesis of starfish polymersomes.

The enhanced membrane stability and chemical versatility of polymeric vesicles have made them promising tools in micro/nanoreactors, drug delivery, cell mimicking, etc. However, shape control over polymersomes remains a challenge and has restricted their full potential. Here we show that local curvature formation on the polymeric membrane can be controlled by applying poly(N-isopropylacrylamide) as a responsive hydrophobic unit, while adding salt ions to modulate the properties of poly(N-isopropylacrylamide) and its interaction with the polymeric membrane. Polymersomes with multiple arms are fabricated, and the number of arms could be tuned by salt concentration. Furthermore, the salt ions are shown to have a thermodynamic effect on the insertion of poly(N-isopropylacrylamide) into the polymeric membrane. This controlled shape transformation can provide evidence for studying the role of salt ions in curvature formation on polymeric membranes and biomembranes. Moreover, potential stimuli-responsive non-spherical polymersomes can be good candidates for various applications, especially in nanomedicine.

An injectable hemostatic PEG-based hydrogel with on-demand dissolution features for emergency care.

Uncontrolled bleeding from internal noncompressible wounds is a major cause of prehospital death in military personnel and civilian populations. An ideal hemostatic sealant for emergency care should quickly control blood loss and be removed without debridement for the follow-up treatment in the operating room, yet the lack of suitable materials to meet both requirements is the bottleneck. Herein, we suggest an injectable and dissolvable hydrogel sealant for hemorrhage management of noncompressible wounds. To this end, a 4-arm poly(ethylene glycol) (PEG) crosslinker modified with thioester linkages and terminated with aldehyde groups is designed and synthesized, and to modulate the gel properties and make it suitable as a hemostatic sealant, a mixed amino component composed of poly(ethylene imine) and adipic dihydrazide is employed to react with the PEG crosslinker to form the adhesive and elastic sealant for the first time. The aldehyde groups provide the adhesion to the tissues, and the amino component affords the procoagulant ability. More importantly, the thioester moieties allow the on-demand dissolution of sealant via a thiol-thioester exchange reaction upon exposure to an exogenous thiolate solution. In the rat femoral artery puncture and liver injury models, the administration of the hydrogel sealant dramatically reduces blood loss, and its subsequent removal does not induce rebleeding. Consequently, this hydrogel sealant with the unique feature of on-demand dissolution can not only efficiently control bleeding in emergent scenarios, but also allow non-traumatic re-exposure of wounds during subsequent surgical care. STATEMENT OF SIGNIFICANCE: Sealants, adhesives or hemostatic dressings currently used in emergency situations not only require manual pressure to control bleeding, but also face removal by cutting and mechanical debridement to enable eventual surgical treatment. In this study, we design and develop an injectable and adhesive hydrogel sealant with good procoagulant capacity and on-demand dissolution feature. The application of the hydrogel sealant substantially reduces bleeding from internal noncompressible wounds without the need for direct pressure, and demonstrates for the first time that its controlled removal without debridement does not cause rebleeding. Considering that there are currently no commercial wound sealant systems with the feature of on-demand dissolution, the hydrogel sealant developed by us is expected to address an unmet clinical need.

Microfluidic preparation of polymer-lipid Janus microparticles with staged drug release property.

This work demonstrated a microfluidic preparation process for novel Janus microparticles with individual drug release properties in each compartment. A flow-focusing microfluidic chip was designed to produce oil-in-water droplets from a mixed solution of poly(lactic-co-glycolic acid) and a triglyceride type lipid. Based on solvent evaporation-induced phase separation, droplets evolved and were solidified into Janus particles, each of which had a polymer compartment and a lipid compartment. The ratio of the two compartments in a particle can be discretionarily regulated, and the particle structure can also be flexibly altered to Janus-patchy, triple, quadruple or core-shell type. Phase transition of the chosen lipid from solid to liquid would occur under physiological temperature, which was applied for rapid release of the loaded drug. The polymer compartment would undergo a slow degradation process in physiological environment, facilitating sustained drug release. Paclitaxel was loaded into Janus particles during preparation, and staged release was achieved, leading to a combination of rapid and sustained release, which is highly desired in target drug delivery. This study would start the application of hybrid Janus particles of polymer-lipid type with novel release kinetics in drug delivery systems.

Three-dimensional poly(lactic-co-glycolic acid)/silica colloidal crystal microparticles for sustained drug release and visualized monitoring.

In this paper, a three-dimensional (3D) poly(lactic-co-glycolic acid) (PLGA)/silica colloidal crystal drug delivery system with sustained drug release and visualized release monitoring was developed. This system had employed silica colloidal crystal microparticles as template skeleton, PLGA as drug carrier and dexamethasone (DEX) as therapeutic agent. The fabrication of the microparticle-based system included droplet formation based-on microfluidics, silica nanoparticle self-assembly and layer-by-layer deposition of PLGA containing DEX. In 370 µm droplets, the silica colloidal nanoparticles could self-assemble orderly into microparticles with a diameter of 187 µm, featuring red structure color. During the deposition of PLGA with the drug into the voids of the template microparticles, the reflection peak red-shifted and weakened until the voids were completely filled. Owing to the gradual degradation of PLGA, the release of DEX was triggered and sustained for 4 weeks with a cumulative release of 94.9%, while the structure color of the microparticles recovered during the release process. The color change could be recognized by the naked eyes, which would benefit the non-invasive monitoring of the drug release. The in vitro cytotoxicity and long-term inhibiting proliferation were investigated on retinal pigment epithelial cells. The inhibition effect of DEX released from the microparticles showed concentration-dependence from 40 to 200 µg mL-1 and time-dependence within 7 days. As a sustained drug delivery system with self-reporting drug release, the particles have potential applications in treatment of intraocular diseases.

Sustained Codelivery of Cisplatin and Paclitaxel via an Injectable Prodrug Hydrogel for Ovarian Cancer Treatment.

The sustained release of both the hydrophilic drug and hydrophobic drug from one delivery system remains challenging in pharmaceutics and biomaterials science. The combination of hydrophilic cisplatin and hydrophobic paclitaxel (PTX) exhibits a clinical survival advantage compared with the individual drug therapy against various tumors such as ovarian cancer. In this study, a localized, long-term codelivery system of cisplatin and PTX was developed using an injectable and thermosensitive polymer-platinum(IV) conjugate hydrogel as the carrier. The thermosensitive Bi(mPEG-PLGA)-Pt(IV) (PtGel) conjugate was synthesized via covalently linking two mPEG-PLGA copolymers onto a Pt(IV) prodrug, and its concentrated aqueous solution exhibited a reversible sol-gel transition upon heating. Meanwhile, the core-corona micelles formed by the amphiphilic conjugates in water could serve as a reservoir for the solubilization of PTX, and thus an injectable binary drug-loaded hydrogel formulation was obtained. We also found that the introduction of PTX into the conjugate hydrogel decreased its sol-gel transition temperature and improved its gel strength. In vitro release experiments showed that both of the loaded drugs were released in a sustained manner for as long as 2.5 months, which was the longest combination delivery of these two drugs ever reported. In vitro cellular assays revealed that the dual-drug system exhibited a synergistic anticancer effect against ovarian cancer cells. Finally, using the SKOV-3 ovarian cancer xenograft mouse model, we demonstrated that a single injection of the PTX-loaded conjugate hydrogel system resulted in enhanced anticancer efficacy and significantly reduced the side effects, when compared with the multiple injections of the free drug combination.

Water management challenges in the context of agricultural intensification and endemic fluorosis: the case of Yuanmou County.

Yuanmou County in Yunnan Province, China is situated in a dry hot valley where annual evaporation is almost six times the annual rainfall and thus the county suffers from chronic water shortages. Since the early 1980s the county has taken advantage of local warm climate and focused its economic development strategy on commercial vegetable plantations. This strategy successfully brings high income to the local government and farmers, but increases water consumption and adds an extra stressor to the already diminished water resources. Yuanmou County is one of the endemic fluorosis hotspots in China where both dental and skeletal fluorosis cases have been found among local villagers that were diagnosed as being water-borne. Despite measures to adapt to water shortages and control fluorosis taken by the local government and communities, new challenges are emerging. Herein, we describe the water management challenges facing the county as well as document the coping strategies adopted by the government and communities, analyze remaining and emerging challenges, and suggest an ecohealth framework for better management of water resources in Yuanmou.