Rotational Intravascular Multidirectional Ultrasound Catheter for Sonothrombolysis of Retracted Clots:An in Vitro and in Vivo Study

Thromboembolism in blood vessels poses a serious risk of stroke,heart attack,and even sudden death if not properly managed.Sonothrombolysis combined with ultrasound contrast agents has emerged as a promising approach for the effective treatment of thromboembolism.Recent reports have highlighted the potential of intravascular sonothrombolysis as a safe and effective treatment modality for deep vein thrombosis(DVT).However,its efficiency has not been validated through in vivo testing of retracted clots.This study aimed to develop a miniaturized multidirectional transducer featuring two 4-layer lead zir-conate titanate(PZT-5A)stacks with an aperture size of 1.4 mm1.4 mm,enabling both forward-and side-looking treatment.Integrated into a custom two-lumen 10-French(Fr)catheter,the capability of this device for intravascular sonothrombolysis was validated both in vitro and in vivo.With low-dose tissue plasminogen activators and nanodroplets,the rotational multidirectional transducer reduced the retracted clot mass(800 mg)by an average of 52%within 30 min during in vitro testing.The lysis rate was significantly higher by 37%than that in a forward-viewing transducer without rotation.This improvement was particularly noteworthy in the treatment of retracted clots.Notably,a long-retracted clot(>10 cm)was successfully treated within 40 min in vivo by creating a flow channel with a diameter>4 mm in a porcine DVT model.In conclusion,these findings strongly suggest the potential of this technique for clinical applications in sonothrombolysis,offering a feasible solution for effectively treating thromboembolism,particularly in challenging cases involving retracted clots.

Identification of stable normalization genes for quantitative real-time PCR in porcine articular cartilage

Background： Expression levels for genes of interest must be normalized with an appropriate reference, or housekeeping gene, to make accurate comparisons of quantitative real-time PCR results. The purpose of this study was to identify the most stable housekeeping genes in porcine articular cartilage subjected to a mechanical injury from a panel of 10 candidate genes. Results： Ten candidate housekeeping genes were evaluated in three different treatment groups of mechanically impacted porcine articular cartilage. The genes evaluated were： beta actin, beta-2-microglobulin, glyceraldehyde-3-phosphate dehydrogenase, hydroxymethylbilane synthase, hypoxanthine phosphoribosyl transferase, peptidylprolyl isomerase A （cyclophilin A）, ribosomal protein L4, succinate dehydrogenase flavoprotein subunit A, TATA box binding protein, and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein--zeta polypeptide The stability of the genes was measured using geNorm, BestKeeper, and NormFinder software. The four most stable genes measured via geNorm were （most to least stable） succinate dehydrogenase flavoprotein, subunit A, peptidylprolyl isomerase A, glyceraldehyde-3-phosphate dehydrogenase, beta actin; the four most stable genes measured via BestKeeper were glyceraldehyde-3-phosphate dehydrogenase, peptidylprolyl isomerase A, beta actin, succinate dehydrogenase flavoprotein, subunit A; and the four most stable genes measured via NormFinder were peptidylprolyl isomerase A, sucdnate dehydrogenase flavoprotein, subunit A, glyceraldehyde-3-phosphate dehydrogenase, beta actin. Conclusions： BestKeeper, geNorm, and NormFinder all generated similar results for the most stable genes in porcine articular cartilage. The use of these appropriate reference genes will facilitate accurate gene expression studies of porcine articular cartilage and suggest appropriate housekeeping genes for articular cartilage studies in other species.

Confinement-induced nanocrystal alignment of conjugated polymer by the soft-stamped nanoimprint lithography

Soft-stamped nanoimprint lithography（NIL） is considered as one of the most effective processes of nanoscale patterning because of its low cost and high throughput. In this work, this method is used to emboss the poly（9, 9-dioctylfluorene）film. By reducing the linewidth of the nanogratings on the stamp, the orientations of nanocrystals are confined along the grating vector in the nanoimprint process, where the confinement linewidth is comparable to the geometrical size of the nanocrystal. When the linewidth is about 400 nm, the poly（9, 9-dioctylfluorene）（PFO） nanocrystals could be orderly arranged in the nanogratings, so that both pattern transfer and well-aligned nanocrystal arrangement could be achieved in a single step by the soft-stamped NIL. The relevant mechanism of the nanocrystalline alignment in these nanogratings is fully discussed. The modulation of nanocrystal alignment is of benefit to the charge mobilities and other performances of PFO-based devices for the future applications.

A Biodegradable Knitted Cardiac Patch for Myocardium Regeneration Using Cardiosphere-Derived Cells(CDCs)

In order to regenerate myocardium and provide appropriate mechanical support after a heart attack,jersey,tuck and rib stitch structures were knitted from polylactic acid(PLA)yarns to fabricate a cardiac patch,which mimicked the mechanical properties of myocardium in both directions.Cardiosphere-derived cells(CDCs) were seeded on these PLA patch fabrics,and using scanning electron microscopy(SEM) characterization and an MTT assay the cells proliferated and attached successfully to the PLA fabrics.Based on the results,the rib stitch structure is the most promising candidate for fabricating cardiac patches due to its high elasticity and its ability to promote cell proliferation.

Multi-modal investigation of the bone micro- and ultrastructure, and elemental distribution in the presence of Mg-xGd screws at mid-term healing stages

Magnesium(Mg)–based alloys are becoming attractive materials for medical applications as temporary bone implants for support of fracture healing,e.g.as a suture anchor.Due to their mechanical properties and biocompatibility,they may replace titanium or stainless-steel implants,commonly used in orthopedic field.Nevertheless,patient safety has to be assured by finding a long-term balance between metal degradation,osseointegration,bone ultrastructure adaptation and element distribution in organs.In order to determine the implant behavior and its influence on bone and tissues,we investigated two Mg alloys with gadolinium contents of 5 and 10 wt percent in comparison to permanent materials titanium and polyether ether ketone.The implants were present in rat tibia for 10,20 and 32 weeks before sacrifice of the animal.Synchrotron radiation-based micro computed tomography enables the distinction of features like residual metal,degradation layer and bone structure.Additionally,X-ray diffraction and X-ray fluorescence yield information on parameters describing the bone ultrastructure and elemental composition at the bone-to-implant interface.Finally,with element specific mass spectrometry,the elements and their accumulation in the main organs and tissues are traced.The results show that Mg-xGd implants degrade in vivo under the formation of a stable degradation layer with bone remodeling similar to that of Ti after 10 weeks.No accumulation of Mg and Gd was observed in selected organs,except for the interfacial bone after 8 months of healing.Thus,we confirm that Mg-5Gd and Mg-10Gd are suitable material choices for bone implants.

Ultrasound-triggered noninvasive regulation of blood glucose levels using microgels integrated with insulin nanocapsules

Diabetes is a serious public health problem affecting 422 million people worldwide. Traditional diabetes management often requires multiple daily insulin injections, associated with pain and inadequate glycemia control. Herein, we have developed an ultrasound-triggered insulin delivery system capable of pulsatile insulin release that can provide both long-term sustained and fast on-demand responses. In this system, insulin-loaded poly（lactic-co-glycolic acid） （PLGA） nanocapsules are encapsulated within chitosan microgels. The encapsulated insulin in nanocapsules can passively diffuse from the nanoparticle but remain restricted within the microgel. Upon ultrasound treatment, the stored insulin in microgels can be rapidly released to regulate blood glucose levels. In a chemically-induced type I diabetic mouse model, we demonstrated that this system, when activated by 30 s ultrasound administration, could effectively achieve glycemic control for up to one week in a noninvasive, localized, and pulsatile manner.

Shape-controlled synthesis of liquid metal nanodroplets for photothermal therapy

The capping agents for liquid metal (LM) nanodroplets in aqueous solutions are restricted to thiol-containing and positively-charged molecules or macromolecules.However,both thiolate-metal complex and electrostatic interaction are liable to detachment upon strong mechanical forces such as sonication,leading to limited stability and applications.To address this,we utilized ultrasmall water soluble melanin nanoparticles (MNPs) as the capping agent,which exhibited strong metal binding capability with the oxide layer of gallium based LMs and resulted in enhanced stability.Interestingly,shape-controlled synthesis of LM nanodroplets can be achieved by the incorporation of MNPs.Various EGaln nanostructures including nanorice,nanosphere and nanorod were obtained by simply tuning the feed ratio,sonication time,and suspension temperature.Among these shapes,EGaln nanorice has the best photothermal conversion efficiency,which could be leveraged for photothermal therapy.

A trifunctional contraceptive gel enhances the safety and quality of sexual intercourse

Current contraceptive methods come with a number of drawbacks,including low efficacy,in the case of commercial contraceptive gels,and a reduction in the quality of sexual intercourse,in the case of condoms.Adding pharmacologically-active agents to contraceptive gels holds the potential to improve sexual experience,and hardbor safety and hygiene.In this study,we fabricated a carbomer-based contraceptive gel consisting of three agents:tenofovir,gossypol acetate,and nitroglycerin(TGN),with pH adjusted to 4.5(to be compatible with the vagina).In vitro,the gossypol component of the contraceptive gel proved to be an effective spermicide.When the concentration of gossypol acetate was 10 mg/ml,the spermicidal ability reached 100%after 30 s.In addition,tenofovir in the gel significantly inhibited lentiviral transfection efficiency in cell-containing media.In 6 pairs of rats,the gel successfully prevented all females from conceiving after successful mating.Moreover,increased sexual frequency and enhanced erection,which were promoted by the nitroglycerin in the components,were observed in male rats that had the gel applied to their penises.This novel TGN contraceptive gel yielded a higher contraceptive success rate than that of the commercial contraceptive gel(Contragel®).In addition,it has the added benefits to prevent sexually transmitted diseases and improve male libido and erectile function during sexual intercourse.Combining three FDA-approved and marketed agents together,our trifunctional TGN gel has a great potential for further translation and commercialization.

Nanodroplet-mediated catheter-directed sonothrombolysis of retracted blood clots

One major challenge in current microbubble(MB)and tissue plasminogen activator(tPA)-mediated sonothrombolysis techniques is effectively treating retracted blood clots,owing to the high density and low porosity of retracted clots.Nanodroplets(NDs)have the potential to enhance retracted clot lysis owing to their small size and ability to penetrate into retracted clots to enhance drug delivery.For the first time,we demonstrate that a sub-megahertz,forwardviewing intravascular(FVI)transducer can be used for ND-mediated sonothrombolysis,in vitro.In this study,we determined the minimum peak negative pressure to induce cavitation with low-boiling point phase change nanodroplets and clot lysis.We then compared nanodroplet mediated sonothrombolysis to MB and tPA mediate techniques.The clot lysis as a percent mass decrease in retracted clots was 9±8%,9±5%,16±5%,14±9%,17±9%,30±8%,and 40±9%for the control group,tPA alone,tPA+US,MB+US,MB+tPA+US,ND+US,and ND+tPA+US groups,respectively.In retracted blood clots,combined ND-and tPA-mediated sonothrombolysis was able to significantly enhance retracted clot lysis compared with traditional MB and tPA-mediated sonothrombolysis techniques.Combined nanodroplet with tPA-mediated sonothrombolysis may provide a feasible strategy for safely treating retracted clots.

Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds:anterior leaflets,posterior leaflets,and chordae tendineae

Mitral valve(MV)tissue engineering is still in its early stage,and one major challenge in MV tissue engineering is to identify appropriate scaffold materials.With the potential of acellular MV scaffolds being demonstrated recently,it is important to have a full understanding of the biomechanics of the native MV components and their acellular scaffolds.In this study,we have successfully characterized the structural and mechanical properties of porcine MV components,including anterior leaflet(AL),posterior leaflet(PL),strut chordae,and basal chordae,before and after decellularization.Quantitative DNA assay showed more than 90%reduction in DNA content,and Griffonia simplicifolia(GS)lectin immunohistochemistry confirmed the complete lack of porcine𝛼-Gal antigen in the acellular MV components.In the acellular AL and PL,the atrialis,spongiosa,and fibrosa trilayered structure,along with its ECM constitutes,i.e.,collagen fibers,elastin fibers,and portion of GAGs,were preserved.Never-theless,the ECM of both AL and PL experienced a certain degree of disruption,exhibiting a less dense,porous ECM morphology.The overall anatomical morphology of the strut and basal chordae were also maintained af-ter decellularization,with longitudinal morphology experiencing minimum disruption,but the cross-sectional morphology exhibiting evenly-distributed porous structure.In the acellular AL and PL,the nonlinear anisotropic biaxial mechanical behavior was overall preserved;however,uniaxial tensile tests showed that the removal of cellular content and the disruption of structural ECM did result in small decreases in maximum tensile modulus,tissue extensibility,failure stress,and failure strain for both MV leaflets and chordae.

An infusible biologically active adhesive for chemotherapy-related heart failure in elderly rats

Chemotherapy-induced cardiotoxicity with subsequent heart failure(HF)is a major cause of morbidity and mortality in cancer survivors worldwide.Chemotherapy-induced HF is exceptionally challenging as it generally manifests in patients who are typically not eligible for left ventricular device implantation or heart transplantation.To explore alternative treatment strategies for cancer survivors suffering from chemotherapy-induced HF,we developed a minimally invasive infusible cardiac stromal cell secretomes adhesive(MISA)that could be delivered locally through an endoscope-guided intrapericardial injection.To mimic the typical clinical presentation of chemotherapy-induced HF in elder patients,we established an aged rat model in which restrictive cardiomyopathy with sequential HF was induced via consecutive doxorubicin injections.In vitro,we prove that MISA not only enhanced cardiomyocytes proliferation potency and viability,but also inhibited their apoptosis.In vivo,we prove that MISA improved the ventricular contractility indexes and led to beneficial effects on histological and structural features of restrictive cardiomyopathy via promoting cardiomyocyte proliferation,angiogenesis,and mitochondrial respiration.Additionally,we also evaluated the safety and feasibility of MISA intrapericardial delivery in a healthy porcine model with an intact immune system.In general,our data indicates that MISA has a strong potential for translation into large animal models and ultimately clinical applications for chemotherapy-induced HF prior to the final option of heart transplantation.

Radiopaque FeMnN-Mo composite drawn filled tubing wires for braided absorbable neurovascular devices

Flow diverter devices are small stents used to divert blood flow away from aneurysms in the brain,stagnating flow and inducing intra-aneurysmal thrombosis which in time will prevent aneurysm rupture.Current devices are formed from thin(~25μm)wires which will remain in place long after the aneurysm has been mitigated.As their continued presence could lead to secondary complications,an absorbable flow diverter which dissolves into the body after aneurysm occlusion is desirable.The absorbable metals investigated to date struggle to achieve the necessary combination of strength,elasticity,corrosion rate,fragmentation resistance,radiopacity,and biocompatibility.This work proposes and investigates a new composite wire concept combining absorbable iron alloy(FeMnN)shells with one or more pure molybdenum(Mo)cores.Various wire configurations are produced and drawn to 25–250μm wires.Tensile testing revealed high and tunable mechanical properties on par with existing flow diverter materials.In vitro degradation testing of 100μm wire in DMEM to 7 days indicated progressive corrosion and cracking of the FeMnN shell but not of the Mo,confirming the cathodic protection of the Mo by the FeMnN and thus mitigation of premature fragmentation risk.In vivo implantation and subsequentμCT of the same wires in mouse aortas to 6 months showed meaningful corrosion had begun in the FeMnN shell but not yet in the Mo filament cores.In total,these results indicate that these composites may offer an ideal combination of properties for absorbable flow diverters.

Glucose-responsive oral insulin delivery for postprandial glycemic regulation

Controlling postprandial glucose levels for diabetic patients is critical to achieve the tight glycemic control that decreases the risk for developing long-term micro- and macrovascular complications.Herein,we report a glucose-responsive oral insulin delivery system based on Fc receptor (FcRn)-targeted liposomes with glucose-sensitive hyaluronic acid (HA) shell for postprandial glycemic regulation.After oral administration,the HA shell can quickly detach in the presence of increasing intestinal glucose concentration due to the competitive binding of glucose with the phenylboronic acid groups conjugated with HA.The exposed Fc groups on the surface of liposomes then facilitate enhanced intestinal absorption in an FcRn-mediated transport pathway.In vivo studies on chemically-induced type 1 diabetic mice show this oral glucose-responsive delivery approach can effectively reduce postprandial blood glucose excursions.This work is the first demonstration of an oral insulin delivery system directly triggered by increasing postprandial glucose concentrations in the intestine to provide an on-demand insulin release with ease of administration.

Advances in biomaterials and regenerative medicine for primary ovarian insufficiency therapy

Primary ovarian insufficiency(POI)is an ovarian dysfunction that affects more than 1%of women and is characterized by hormone imbalances that afflict women before the age of 40.The typical perimenopausal symptoms result from abnormal levels of sex hormones,especially estrogen.The most prevalent treatment is hormone replacement therapy(HRT),which can relieve symptoms and improve quality of life.However,HRT cannot restore ovarian functions,including secretion,ovulation,and fertility.Recently,as part of a developing field of regenerative medicine,stem cell therapy has been proposed for the treatment of POI.Thus,we recapitulate the literature focusing on the use of stem cells and biomaterials for POI treatment,and sum up the underlying mechanisms of action.A thorough understanding of the work already done can aid in the development of guidelines for future translational applications and clinical trials that aim to cure POI by using regenerative medicine and biomedical engineering strategies.

Nanomedicine for obesity treatment

Obesity, as a chronic condition, has been a serious public health issue over the last decades both in the affluent Western world and developing countries. As reported, the risk of several serious diseases increases with weight gain, including type 2 diabetes,coronary heart disease, cancer, and respiratory diseases. In addition to lifestyle modifications, pharmacotherapy has become an important strategy to control weight gain. However, most of the anti-obesity drugs often show poor outcome for weight-loss and cause severe adverse effects. This review surveys recent advances in nanomedicine as an emerging strategy for obesity treatment with an emphasis on the enhanced therapeutic efficiency and minimized side effects. The insights for future development are also discussed.

Cell and biomaterial-based approaches to uterus regeneration

Asherman’s syndrome(AS)is an endometrial disorder in which intrauterine adhesions crowd the uterine cavity and wall.The fibrotic adhesions are primarily the result of invasive uterine procedures that usually involve the insertion of surgical equipment into the uterus.This syndrome is accompanied by a number of clinical manifestations,including irregular or painful menstruation and infertility.The most prevalent treatment is hysteroscopy,which involves the physical removal of the fibrous strands.Within the last decade,however,the field has been exploring the use of cellbased therapeutics,in conjunction with biomaterials,to treat AS.This review is a recapitulation of the literature focused on cellular therapies for treating AS.

Light-triggered NO-releasing nanoparticles for treating mice with liver fibrosis

Liver fibrosis, resulting from chronic liver damage and characterized by the accumulation of extracellular matrix (ECM) proteins, is a characteristic of most types of chronic liver diseases. The activation of hepatic stellate cells (HSC) is considered an essential pathological hallmark in liver fibrosis. Although nitric oxide (NO) can effectively induce HSC apoptosis, the systemic administration of NO is ineffective and may cause severe complications such as hypotension. To overcome this limitation, nanoparticles were designed to target HSCs and release NO locally under the exposure of near infrared light (NIR). To achieve this, upconversion nanoparticle (UCNP) cores were enveloped in mesoporous silica shells (UCNP@mSiO2), which were modified with hyaluronic acid (HA-UCNP@mSiO2) and Roussin’s black salt (RBS). HA molecules recognize and bind to CD44 proteins, which are overexpressed on activated HSCs. Under exposure to a 980-nm NIR laser, the UCNP cores convert the 980-nm wavelength into ultraviolet (UV) light, which then energizes the RBS (NO donors), resulting in an efficient release of NO inside of the HSCs. Once released, NO triggers HSC apoptosis and reverses the liver fibrosis. This targeted and controlled release method provides the theoretical and experimental basis for novel therapeutic approaches to treat hepatic fibrosis.

Customized and in situ fenestrated stent-grafts:A reinforced poly-ε-caprolactone branch cuff designed to prevent type III endoleaks and enhance hemodynamics

Superior long-term anchorage of the bridging stent-grafts from the fenestrated main body endograft could be achieved with the addition of a flared cuff,capable of preventing the previously observed fabric fraying around the fenestration as a result of the balloon angioplasty of the seal zone.This novel stent cuff design will also facilitate more complete biointegration of the devices,eliminate the hemodynamic variation as well as significantly reduce the possibility of a Type III endoleak.The feasibility of this concept is demonstrated by observations made from in-situ tests performed in a Beta endograft design.Flared cuffs made of poly(ε-caprolactone)supported with a weft-knitted polyester structure can be manufactured with various configurations to optimize the transition from the main body of the endograft,thus preventing the currently marketed designs’hemodynamic perturbation while also promoting endograft biointegration.This concept represents an evolution in branch graft design,which may enhance the long-term durability of customized fenestrations and open new applications for in-vivo graft fenestration in the near future.Further ongoing investigation to optimize its structure,X-ray opacity,fixation to the flared stent,and material biocompatibility are still required to build upon this concept’s proof.

Hyaluronic acid-based hydrogels with tobacco mosaic virus containing cell adhesive peptide induce bone repair in normal and osteoporotic rats

Tobacco mosaic virus(TMV)has been studied as a multi-functional agent for bone tissue engineering.An osteo-inductive effect of wild-type TMV has been reported,as it can significantly enhance the bone differentiation potential of bone marrow stromal cells both on a two-dimensional substrate and in a three-dimensional(3D)hydrogel system.A TMV mutant(TMV-RGD1)was created which featured the adhesion peptide arginyl-glycyl-aspartic acid(RGD),the most common peptide motif responsible for cell adhesion to the extracellular matrix,on the surface of the virus particle to enhance the bio-functionality of the scaffold material.We hypothesised that the incorporation of either wild-type TMV or TMV-RGD1 in the 3D hydrogel scaffold would induce bone healing in critical size defects of the cranial segmental bone.We have previously tested the virus-functionalised scaffolds,in vitro,with a hyaluronic acid-based system as an in-situ hydrogel platform for 3D cell encapsulation,culture,and differentiation.The results of these experiments suggested the potential of the virus-functionalised hydrogel to promote in vitro stem cell differentiation.The hydrogel-forming system we employed was shown to be safe and biocompatible in vivo.Here,we further explored the physiological responses regarding bone regeneration of a calvarial defect in both normal and osteoporotic ovariectomized rat models.Our results,based on histological analysis in both animal models,suggested that both wild-type TMV and TMV-RGD1 functionalised hydrogels could accelerate bone regeneration,without systemic toxicity,evaluated by blood counts.New bone formation was intensified by the incorporation of the RGD-mutant viral particles.This finding increased the potential for use of the rodshaped plant virus as a platform for the addition of powerful biofunctionality for tissue engineering applications.This study was approved by the Ethics Committee on Animal Use of the Zhenjiang Affiliated First People’s Hospital affiliated to Jiangsu University.

Biodegradable elastomeric circuit boards from citric acid-based polyesters

Recyclable and biodegradable microelectronics,i.e.,“green”electronics,are emerging as a viable solution to the global challenge of electronic waste.Specifically,flexible circuit boards represent a prime target for materials development and increasing the utility of green electronics in biomedical applications.Circuit board substrates and packaging are good dielectrics,mechanically and thermally robust,and are compatible with microfabrication processes.Poly(octamethylene maleate(anhydride)citrate)(POMaC)–a citric acid-based elastomer with tunable degradation and mechanical properties–presents a promising alternative for circuit board substrates and packaging.Here,we report the characterization of Elastomeric Circuit Boards(ECBs).Synthesis and processing conditions were optimized to achieve desired degradation and mechanical properties for production of stretchable circuits.ECB traces were characterized and exhibited sheet resistance of 0.599Ωcm^(−2),crosstalk distance of<0.6 mm,and exhibited stable 0%strain resistances after 1000 strain cycles to 20%.Fabrication of single layer and encapsulated ECBs was demonstrated.