MACULAR HOLE ASSOCIATED WITH AGE-RELATED MACULAR DEGENERATION: Pathogenesis and Surgical Outcomes.

PURPOSE: To ascertain the pathogenesis of macular hole (MH) associated with age-related macular degeneration (AMD) and its surgical outcomes. METHODS: Patients with full-thickness MH associated with AMD (higher grades than intermediate) were enrolled. The mechanism of MH formation and closure rate after vitrectomy (surgical outcome) were determined using optical coherence tomography imaging. RESULTS: The mechanism of MH formation (35 eyes) associated with AMD was classified into four types: vitreomacular traction (42.9%), gradual retinal thinning caused by subretinal drusen or pigment epithelial detachment (22.9%), massive subretinal hemorrhage (20.0%), and combined (14.3%). In the 41 eyes that underwent vitrectomy, the logarithm of the minimum angle of resolution best-corrected visual acuity improved from 0.82 (0.10-2.30) preoperative to 0.69 (0.10-2.30) postoperative (P = 0.001). Successful closure of the MH was achieved in 33 eyes (80.5%) after vitrectomy. No significant association was observed between the closure rate of MH after vitrectomy and mechanism of MH formation (P = 0.083). CONCLUSION: The mechanism of MH formation associated with AMD was classified into four types and was not related to its surgical outcome. Considering visual improvement and surgical outcome after vitrectomy in our study, active surgical treatment can be considered for MH associated with AMD.

Suture Fiber Reinforcement of a 3D Printed Gelatin Scaffold for Its Potential Application in Soft Tissue Engineering.

Gelatin has excellent biological properties, but its poor physical properties are a major obstacle to its use as a biomaterial ink. These disadvantages not only worsen the printability of gelatin biomaterial ink, but also reduce the dimensional stability of its 3D scaffolds and limit its application in the tissue engineering field. Herein, biodegradable suture fibers were added into a gelatin biomaterial ink to improve the printability, mechanical strength, and dimensional stability of the 3D printed scaffolds. The suture fiber reinforced gelatin 3D scaffolds were fabricated using the thermo-responsive properties of gelatin under optimized 3D printing conditions (-10 °C cryogenic plate, 40-80 kPa pneumatic pressure, and 9 mm/s printing speed), and were crosslinked using EDC/NHS to maintain their 3D structures. Scanning electron microscopy images revealed that the morphologies of the 3D printed scaffolds maintained their 3D structure after crosslinking. The addition of 0.5% (w/v) of suture fibers increased the printing accuracy of the 3D printed scaffolds to 97%. The suture fibers also increased the mechanical strength of the 3D printed scaffolds by up to 6-fold, and the degradation rate could be controlled by the suture fiber content. In in vitro cell studies, DNA assay results showed that human dermal fibroblasts' proliferation rate of a 3D printed scaffold containing 0.5% suture fiber was 10% higher than that of a 3D printed scaffold without suture fibers after 14 days of culture. Interestingly, the supplement of suture fibers into gelatin biomaterial ink was able to minimize the cell-mediated contraction of the cell cultured 3D scaffolds over the cell culture period. These results show that advanced biomaterial inks can be developed by supplementing biodegradable fibers to improve the poor physical properties of natural polymer-based biomaterial inks.

Chitosan for Tissue Engineering.

Chitosan, a deacetylated chitin, is one of the few natural polymers similar to glycosaminoglycans (GAGs) widely distributed throughout connective tissues. It has been believed that the excellent biocompatibility of chitosan is largely attributed to this structural similarity. Chitosan is also known to possess biodegradability, antimicrobial activity and low toxicity and immunogenicity which are essential for scaffolds. In addition, the existence of free amine groups in its backbone chain enables further chemical modifications to create the additional biomedical functionality. For these reasons, chitosan has found a tremendous variety of biomedical applications in recent years. This chapter introduces the basic contents of chitosan and discusses its applications to artificial skin, artificial bone, and artificial cartilage in tissue engineering purpose.

MRI Monitoring of Tumor-Selective Anticancer Drug Delivery with Stable Thermosensitive Liposomes Triggered by High-Intensity Focused Ultrasound.

Monitoring of drug release from a heat-activated liposome carrier provides an opportunity for real-time control of drug delivery and allows prediction of the therapeutic effect. We have developed short-chain elastin-like polypeptide-incorporating thermosensitive liposomes (STLs). Here, we report the development of STL encapsulating gadobenate dimeglumine (Gd-BOPTA), a MRI contrast agent, and doxorubicin (Dox) (Gd-Dox-STL). The Dox release profile from Gd-Dox-STL was comparable to Gd-Dox-LTSL; however, the serum stability of Gd-Dox-STL was much higher than Gd-Dox-LTSL. MRI studies showed that the difference in T1 relaxation time between 37 and 42 °C for Gd-Dox-STL was larger than the difference for Gd-Dox-LTSL. Although relaxivity for both liposomes at 42 °C was similar, the relaxivity of Gd-Dox-STL at 37 °C was 2.5-fold lower than that of Gd-Dox-LTSL. This was likely due to Gd-BOPTA leakage from the LTSL because of low stability at 37 °C. Pharmacokinetic studies showed plasma half-lives of 4.85 and 1.95 h for Gd-Dox-STL and Gd-Dox-LTSL, respectively, consistent with in vitro stability data. In vivo MRI experiments demonstrated corelease of Dox and Gd-BOPTA from STL under mild hyperthermia induced by high-intensity focused ultrasound (HIFU), which suggests STL is a promising tumor selective formulation when coupled with MR-guided HIFU.

Anti-VEGF PolysiRNA Polyplex for the Treatment of Choroidal Neovascularization.

Choroidal neovascularization (CNV) is a major cause of severe vision loss in patients with age-related macular degeneration (AMD). Present ocular siRNA delivery technology is limited due to poor delivery through the retina to the choroid, where CNV originates. Our goal was to develop an optimized nanosized polyRNAi-based therapeutic delivery system to the subretinal space. We developed it by siRNA multimerization (polysiRNA) followed by coating with branched polyethylenimine and hyaluronic acid, and then evaluated its efficacy in vitro and in vivo. The polysiRNA polyplex showed a narrow size distribution (260.7 ± 43.27 nm) and negative charge (-4.98 ± 0.47 mV) owing to the hyaluronic acid outer layer. In vitro uptake of the polysiRNA polyplex by human ARPE cells was discovered, and the direct inhibition of VEGF mRNA translation was confirmed in B16F10 cells. The intravitreally administered polysiRNA polyplex overcame both the vitreous and retina barriers in vivo and reached the subretinal space efficiently. Intravitreal injection of the polysiRNA polyplex was not toxic to the retina in histopathology. Furthermore, intravitreal injections of the polysiRNA polyplex at both 1 and 7 days after laser photocoagulation inhibited laser-induced choroidal neovascularization, compared to that of the control (p < 0.05). These results suggest that anti-VEGF polysiRNA polyplexes show great potential in delivering multimeric RNAi-based therapeutics to treat retinal or choroidal disorders.

Fabrication of conductive polymer-based nanofiber scaffolds for tissue engineering applications.

Natural and synthetic polymers, in particular those that are conductive, are of great interest in the field of tissue engineering and the pursuit of biomimetic extracellular matrix (ECM) structures for adhesion, proliferation, and differentiation of cells. In the present study, natural chitin and conductive polyaniline (PANi) blended solutions were electrospun to produce biodegradable and conductive biomimetic nanostructured scaffolds. The chitin/PANi (Chi-PANi) nanofibrous materials were characterized using field emission scanning electron microscopy, Fourier transform-infrared spectroscopy, wettability analysis, mechanical testing, and electrical conductivity measurements using a 4-point probe method. The calculated electrical conductivities of the PANi-containing nanofiber scaffolds significantly increased as the amount of PANi increased, reaching 5.21 ± 0.28 x 10(-3) S/cm for 0.3 wt% content of the conducting polymer. In addition, the viability of human mesenchymal stem cells (hMSCs) cultured on the Chi-PANi nanofiber scaffolds in vitro was found to be excellent. These results suggest that the Chi-PANi nanofiber scaffolds have great potential for use in tissue engineering applications that involve electrical stimulation.

Changes in retro-odontoid mass after upper cervical spine surgery.

A non-neoplastic mass posterior to the dens is termed a retro-odontoid mass (R-OM). This retrospective study evaluated radiographic and clinical outcomes and R-OM changes after upper cervical spine surgery. This study included 69 patients who underwent upper cervical spine surgery, including atlantoaxial fusion, occipitocervical fusion, or decompression. All patients underwent preoperative magnetic resonance imaging (MRI). Six-month follow-up MRI examinations were performed in 30 patients who had preoperative R-OMs. Radiographic outcomes of the anterior and posterior atlantodental intervals were measured using X-rays and computed tomography. The R-OM and space available for the cord (SAC) were measured using MRI. Clinical outcomes were evaluated using neck and arm pain visual analog scales, the Japanese Orthopedic Association score, the neck disability index, and the patient-reported subjective improvement rate. The anterior atlantodental interval decreased, while the posterior atlantodental interval and SAC increased postoperatively. Among the clinical outcomes, the neck and arm pain and the neck disability index decreased postoperatively, while the Japanese Orthopedic Association score increased. All clinical and radiographic outcomes improved postoperatively. The R-OM either decreased in size or disappeared after fusion surgery in all cases, except in one patient who underwent decompression surgery. In conclusion, stabilization through fusion surgery is essential for treating R-OM.

Comparison of Temperature and Pain Changes between the Drip and Topical Methods of Administering the Transnasal Sphenopalatine Ganglion Block.

The objective of this study was to compare facial temperatures and the visual analogue scale (VAS) between the drip method and the topical method of transnasal sphenopalatine ganglion block (SPGB). The transnasal SPGB is administered to patients with facial or head and neck pain. In the transnasal approach, the drip and topical methods are frequently used. We compared facial temperatures and VAS after transnasal SPGB. Medical records of 74 patients who visited the pain clinic and underwent transnasal SPGB were retrospectively reviewed. A total of 156 transnasal SPGB were performed. The patients were divided into the drip-method and topical-method groups. Facial temperatures were measured in six areas of the right and left forehead, maxilla, and mandible before and 30 min after completion of the transnasal SPGB. Temperatures were compared before and 30 min after SPGB in each group and between the two groups. VAS scores were compared at the same times of SPGB in each group and between the two groups. In the drip-method group, there were significant increases at four areas of the face in temperature changes at 30 min after SPGB. In the topical-method group, there was no significant difference in the temperature changes at 30 min after SPGB. There were statistically significant differences in the facial temperature changes between the two groups in the right forehead (p = 0.001), left forehead (p = 0.015), and right maxillary area (p = 0.046). In herpes zoster, there were statistically significant differences in the VAS scores between before and 30 min after SPGB in both groups (p < 0.001, p = 0.008) and between two groups (p < 0.001). In migraine, there were statistically significant differences in VAS scores between before and 30 min after SPGB in both groups (p < 0.001, p = 0.004) and between two groups (p = 0.014). Transnasal SPGB using two methods showed different temperature changes and VAS scores.

Efficacy of bone formation of microporous sphere-shaped biphasic calcium phosphate in a rabbit skull bone defect model.

Bone graft is required in various surgical procedures. Although autograft is the gold standard, it has limited availability. Various compounds have been proposed as alternatives such as biphasic calcium phosphate (BCP), which is the most widely used compound. The newly synthesized microporous sphere-shaped BCP has the advantage of increasing contact surface, and it can induce the formation of microbone structures. A putty-type contains the addition of a fluid carrier to the sphere-shaped BCP and can be easily used for a small orifice large bone defect. To compare the widely used BCP products, new bone formation and residual graft materials (RGM) were evaluated for 6 and 12 weeks in a rabbit calvarial bone defect model. Although existing BCP products and the microporous sphere-type product did not differ significantly with respect to new bone formation and RGM, the putty-type product was largely washed out and had low new bone formation at 6 and 12 weeks. Overall, the results suggest that microporous sphere-shaped BCP showed similar bone formation capability to existing products and was able to maintain higher initial mechanical stability.

In situ polytetrafluoroethylene graft bypass for primary infected aneurysm of the infrarenal abdominal aorta.

BACKGROUND: Reinfection is a major issue of surgical treatment for patients with infected abdominal aortic aneurysm (AAA). The present report describes outcomes after use of our procedure for treating patients with infected aneurysm of the infrarenal abdominal aorta. The procedure involved an in situ polytetrafluoroethylene (PTFE) graft bypass and omental wrapping of the graft. The procedure was used regardless of the presence of Gram-stain-positive pus or tissue or the type of pathogen identified. METHODS: We retrospectively reviewed nine consecutive patients with primary infected aneurysms of the infrarenal abdominal aorta treated from June 2001 to August 2006 at the Asan Medical Center, Seoul, Korea. Diagnosis was based on preoperative abdominopelvic CT scans. Treatment involved removal of all infected tissue, including infected aorta tissue, in situ PTFE graft reconstruction, and wrapping of the graft with retrocolically transposed great omentum. Sensitive antibiotics were administered before and after the operation. RESULTS: In all cases, aneurysms were the result of aortitis and aortic wall perforation, and presented as aortic pseudoaneurysms with rupture. The pathogens identified were Salmonella non-typhi (n = 4), Klebsiella pneumoniae (n = 2), Streptococcus pneumoniae (n = 1), Citrobacter freundii (n = 1), and Brucella abortus (n = 1). There was no infection-related morbidity or mortality during a median follow-up period of 49 months. CONCLUSIONS: Surgical treatment comprising complete removal of all infected tissue, in situ PTFE graft reconstruction, and omental wrapping of the graft was effective in treating infected AAA. Key adjunct procedures were a precise preoperative diagnosis using abdominopelvic CT scans, and pre- and postoperative sensitive antibiotic treatment.

Three-Dimensional Culture of Salivary Gland Stem Cell in Orthotropic Decellularized Extracellular Matrix Hydrogels.

Radiotherapy in patients with cancer can kill cancer cells but also damage normal cells or tissues. During the treatment of patients with head and neck cancer or thyroid cancer, hyposalivation is a representative chronic side effect of radio-damaged salivary glands (SGs). The major symptom of hyposalivation is mouth dryness, resulting in several subsequent long-term complications. No effective therapeutic approaches have been developed to manage this symptom. In this study, we developed the first rat SG tissue-derived decellularized extracellular matrix hydrogel (DSGM-hydrogel) as a functional orthotropic bioscaffold for future efficient SG stem cell therapy. DSGM-hydrogels were characterized by rheological or biochemical analyses, and rat SG stem/progenitor cells (rSGSCs) were then subjected to three-dimensional culture in the DSGM-hydrogels. Interestingly, DSGM-hydrogel-embedded rSGSCs survived and expressed SG functional differentiation marker of amylase IA and increased enzyme activity of α-amylase in protein level, whereas they showed reduced levels of adult ductal stem/progenitor markers, including c-Kit, c-Met, and CD44. Furthermore, the expression levels of basic epithelial tight junction markers were recovered to levels similar to those naked SG tissues after culture in DSGM-hydrogels in transcription level. Therefore, our findings suggested that the DSGM-hydrogels could provide an appropriate microenvironment for stem/progenitor cell survival and a source of SG cytodifferentiation. This approach could be an applicable method to SG stem cell research as a potential source for an organoid and for clinical regenerative reagents to manage radio-damaged SGs in vivo. Impact Statement In this study, we established the first rat salivary gland (SG) tissue-derived decellularized extracellular matrix hydrogel (DSGM-hydrogel) and assessed the role of this hydrogel as a functional orthotropic bioscaffold. Our findings provide important insights into the applications of the DSGM-hydrogel as a biocompatible matrix for regenerative therapy of radio-damaged SGs.

Effect of cross-linking on the dimensional stability and biocompatibility of a tailored 3D-bioprinted gelatin scaffold.

Biocompatible and biodegradable gelatin is a good candidate bioink for use in 3D bioprinting technologies, but viscous gelatin solution has a low printability. In order to improve the poor printability of gelatin, we optimized the rheological properties of gelatin solution. 3D gelatin scaffolds were then cross-linked using physical or chemical methods to maintain the 3D structure. The physicochemical and biological differences between the two types of cross-linked gelatin scaffolds were studied. Scanning electron microscopy images revealed that the morphologies of the resulting cross-linked 3D scaffolds maintained their structural stabilities. The physically cross-linked 3D scaffolds maintained their surface sizes without a significant decrease (less than a 3% reduction in the surface size was observed) after cross-linking. To evaluate the differences in cell affinity by two types of cross-linking method, human dermal fibroblasts cultured on the cross-linked 3D scaffolds. After 14 days of culturing, DNA assays showed that the cell proliferation rate of the physically cross-linked 3D scaffold was 44% higher than that of the chemically cross-linked 3D scaffold. In conclusion, the optimized physically cross-linked 3D scaffold retained its surface size without significant decreases after cross-linking, as required by 3D-printed patient-specific tissue engineered customized scaffolds, despite the use of water-soluble gelatin hydrogels.

Hysteresis in a carbon nanotube based electroactive polymer microfiber actuator: numerical modeling.

Hysteretic behavior is an important consideration for smart electroactive polymer actuators in a wide variety of nano/micro-scale applications. We prepared an electroactive polymer actuator in the form of a microfiber, based on single-wall carbon nanotubes and polyaniline, and investigated the hysteretic characteristics of the actuator under electrical potential switching in a basic electrolyte solution. For actuation experiments, we measured the variation of the length of the carbon-nanotube-based electroactive polymer actuator, using an Aurora Scientific Inc. 300B Series muscle lever arm system, while electrical potentials ranging from 0.2 V to 0.65 V were applied. Based on the classical Preisach hysteresis model, we presented and validated a numerical model that described the hysteretic behavior of the carbon-nanotube-based electroactive polymer actuator. Inverse hysteretic behavior was also simulated using the model to demonstrate its capability to predict an input from a desired output. This numerical model of hysteresis could be an effective approach to micro-scale control of carbon-nanotube-based electroactive polymer actuators in potential applications.

Evaluation of postoperative complications according to treatment of third molars in mandibular angle fracture.

OBJECTIVES: The aim of this study was to evaluate the implication of third molars in postoperative complications of mandibular angle fracture with open reduction and internal fixation (ORIF). MATERIALS AND METHODS: Data were collected on patients who presented with mandibular angle fracture at our Department of Oral and Maxillofacial Surgery between January 2011 and December 2015. Of the 63 total patients who underwent ORIF and perioperative intermaxillary fixation (IMF) with an arch bar, 49 patients were identified as having third molars in the fracture line and were followed up with until plate removal. The complications of postoperative infection, postoperative nerve injury, bone healing, and changes in occlusion and temporomandibular joint were evaluated and analyzed using statistical methods. RESULTS: In total, 49 patients had third molars in the fracture line and underwent ORIF surgery and perioperative IMF with an arch bar. The third molar in the fracture line was retained during ORIF in 39 patients. Several patients complained of nerve injury, temporomandibular disorder (TMD), change of occlusion, and postoperative infection around the retained third molar. The third molars were removed during ORIF surgery in 10 patients. Some of these patients complained of nerve injury, but no other complications, such as TMD, change in occlusion, or postoperative infection, were observed. There was no delayed union or nonunion in either of the groups. No statistically significant difference was found between the non-extraction group and the retained teeth group regarding complications after ORIF. CONCLUSION: If the third molar is partially impacted or completely nonfunctional, likely to be involved in pathologic conditions later in life, or possible to remove with the plate simultaneously, extraction of the third molar in the fracture line should be considered during ORIF surgery of the mandible angle fracture.

Gelatin blending and sonication of chitosan nanofiber mats produce synergistic effects on hemostatic functions.

To improve the hemostatic function of chitosan nanofiber mats, we studied the synergetic effects of gelatin blending and porosity control. Gelatin-blended-chitosan (Chi-Gel) nanofiber mats were evaluated with respect to surface morphology, mechanical properties and wettability, and functionally tested in a blood clotting study. The blood clotting efficiency of Chi-Gel nanofiber mats using rabbit whole blood in vitro was superior to that of chitosan nanofibers. Moreover, Chi-Gel nanofiber mats with enlarged porosity, produced by ultra-sonication, showed improved blood clotting efficiency, cell viability and cell infiltration compared with non-sonicated Chi-Gel nanofiber mats. Field-emission scanning electron microscopy revealed a richer density of platelets on sonicated nanofiber mats than on non-sonicated nanofiber mats after 3 min of blood clotting. The proliferation of human dermal fibroblast cells on sonicated Chi-Gel nanofiber mats using the DNA assay was higher than that on non-sonicated chitosan nanofiber mats after 7 days of culture. Confocal z-stack images showed that sonicated Chi-Gel nanofiber mats with high porosity supported active cell migration and infiltration into the 3-dimensional nanofiber mats. These results suggest that hydrophilic gelatin blending and sonication of chitosan nanofiber mats yields synergistic effects that not only improve hemostatic function but also promote wound repair.

Improvement of Antitumor Efficacy by Combination of Thermosensitive Liposome with High-Intensity Focused Ultrasound.

High intensity focused ultrasound (HIFU), allowing for precise heating of the deep and local area, is emerging as the source of mild hyperthermia for delivery of doxorubicin (DOX) using thermosensitive liposomes (TSLs). Conventionally, HIFU has been used for intravascular drug release at tumor tissue by inducing mild hyperthermia immediately upon systemic administration of DOX-TSLs. This immediate heating approach (IHA), however, limits the deep penetration of DOX for high anticancer efficacy. In an attempt to maximize the accumulation of DOX at tumor, the delayed heating approach (DHA) has been explored. In this approach, DOX-TSLs were intravenously administered into the tumor-bearing mice after pre-treatment of tumor tissue with HIFU to increase vascular permeability. We developed the fatty acid-cojugated elastinlike polypeptide bearing TSL (FTSL). The DOX-loaded FTSLs had a hydrodynamic size of 142 nm. In vivo biodistribution study demonstrated that DOX-FTSLs were selectively accumulated at tumor tissue with the maximum amount of DOX at 6 h post-injection. Thereafter, the tumor tissue was heated to 42 °C to induce rapid release of DOX from FTSLs. The results have demonstrated that, compared to IHA, DHA significantly enhances the antitumor efficacy of DOX-FTSLs because of their effective penetration to tumor tissue via the enhanced permeation retention effect, followed by rapid release of DOX.

Formulation optimization and in vivo proof-of-concept study of thermosensitive liposomes balanced by phospholipid, elastin-like polypeptide, and cholesterol.

One application of nanotechnology in medicine that is presently being developed involves a drug delivery system (DDS) employing nanoparticles to deliver drugs to diseased sites in the body avoiding damage of healthy tissue. Recently, the mild hyperthermia-triggered drug delivery combined with anticancer agent-loaded thermosensitive liposomes was widely investigated. In this study, thermosensitive liposomes (TSLs), composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-PEG), cholesterol, and a fatty acid conjugated elastin-like polypeptide (ELP), were developed and optimized for triggered drug release, controlled by external heat stimuli. We introduced modified ELP, tunable for various biomedical purposes, to our thermosensitive liposome (e-TSL) to convey a high thermoresponsive property. We modulated thermosensitivity and stability by varying the ratios of e-TSL components, such as phospholipid, ELP, and cholesterol. Experimental data obtained in this study corresponded to results from a simulation study that demonstrated, through the calculation of the lateral diffusion coefficient, increased permeation of the lipid bilayer with higher ELP concentrations, and decreased permeation in the presence of cholesterol. Finally, we identified effective drug accumulation in tumor tissues and antitumor efficacy with our optimized e-TSL, while adjusting lag-times for systemic accumulation.

Temperature-triggered tumor-specific delivery of anticancer agents by cRGD-conjugated thermosensitive liposomes.

One of the most effective methods to treat cancer is the specific delivery of anticancer drugs to the target site. To achieve this goal, we designed an anticancer drug with mild hyperthermia-mediated triggering and tumor-specific delivery. To enhance the thermosensitive drug release, we incorporated elastin-like polypeptide (ELP), which is known to be a thermally responsive phase transition peptide into the dipalmitoylphosphatidylcholine (DPPC)-based liposome surface. Additionally, cyclic arginine-glycine-aspartic acid (cRGD) binds to αvß3 integrin, which is overexpressed in angiogenic vasculature and tumor cells, was introduced on the liposome. ELP-modified liposomes with the cRGD targeting moiety were prepared using a lipid film hydration method, and doxorubicin (DOX) was loaded into the liposome by the ammonium sulfate-gradient method. The cRGD-targeted and ELP-modified DOX-encapsulated liposomes (RELs) formed spherical vesicles with a mean diameter of 181 nm. The RELs showed 75% and 83% DOX release at 42°C and 45°C, respectively. The stability of RELs was maintained up to 12h without the loss of their thermosensitive function for drug release. Flow cytometry results showed that the cellular uptake of DOX in RELs into αvß3 integrin-overexpressing U87MG and HUVEC cells was 8-fold and 10-fold higher, respectively, than that of non-targeting liposomes. Confocal microscopy revealed that REL released DOX only under the mild hyperthermia condition at 42°C by showing the localization of DOX in nuclei and the liposomes in the cytosol. The cell cytotoxicity results demonstrated that REL can efficiently kill U87MG cells through cRGD targeting and thermal triggering. The in vivo tumoral accumulation measurement showed that the tumor-targeting effect of RELs was 5-fold higher than that of non-targeting liposomes. This stable, target-specific, and thermosensitive liposome shows promise to enhance therapeutic efficacy if it is applied along with a relevant external heat-generating medical system.

Fabrication of sonicated chitosan nanofiber mat with enlarged porosity for use as hemostatic materials.

Electrospinning of pure chitosan was employed to obtain a nanofibrous hemostatic material. Owing to the water-solubility of the resulting acidic chitosan nanofibers, the optimum neutralization conditions were identified by testing various alkaline solutions, so that an insoluble material could be achieved. The pore size and thickness of the neutralized chitosan nanofibers mat could be controlled using ultra-sonication. The porosity of the chitosan mat was increased from 79.9% to 97.2% with ultra-sonication treatment for 1 min, and the water absorption time decreased from 110s to 9s. The blood clotting efficiency measured for the sonicated chitosan nanofiber mat was 1.35- and 3.41-fold better than the efficiencies of the Surgicel(®) and chitosan sponge, respectively. In addition, the proliferation of normal human dermal fibroblasts on the sonicated nanofiber mat was found to be 1.4-fold higher than that on the non-sonicated material after 7 days of culture.

Novel temperature-triggered liposome with high stability: formulation, in vitro evaluation, and in vivo study combined with high-intensity focused ultrasound (HIFU).

We developed a novel temperature-sensitive liposome, STL composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-PEG-2000), cholesterol, and a fatty acid conjugated elastin-like polypeptide (ELP). The STL had a unilamellar spherical shape with a mean diameter of 160 nm. Doxorubicin (DOX) was encapsulated by the STL using an ammonium sulfate gradient method with a lipid to drug ratio of 1:0.2 (w/w), resulting in 95% loading efficiency. The STL exhibited better stability than conventional low temperature sensitive liposome (LTSL-lysolipid-based temperature sensitive liposomes; DPPC:MSPC:DSPE-PEG-2000=90:10:4) at 37 °C in the presence of serum; there was rapid release of doxorubicin in the range of 39-42 °C (≥95% release at 42 °C within 10s). A confocal microscope revealed that DOX encapsulated in STL (STL-DOX) was taken up much better by cell nuclei at 42 °C than at 37 °C. The difference in cell viability between 37 and 42 °C was 63% relative to STL-DOX and 18% for LTSL-DOX. The pharmacokinetics (PK) and antitumor effect of STL-DOX combined with high-intensity focused ultrasound (HIFU) were studied, and compared with LTSL. An in vivo study demonstrated that STL-DOX is highly stable, with a long circulating property (half life=2.03±0.77 h) in HIFU-untreated mice, and resulted in significant tumor regression for 2 days after intravenous injection of STL-DOX at 5 mg DOX/kg in combination with HIFU. These results are better than conventional LTSL, for which the blood circulation time is short (0.92±0.17 h) and inhibition of tumor growth is weak. These results indicate that the properties of stability at 37 °C and burst release at 42 °C of STL-DOX act synergistically against tumors.