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The use of bioabsorbable threads has become a common minimally invasive technique for the nonsurgical lifting of sagged facial tissues. It entails the passage of barbed threads that form a support structure under the skin of the face and neck to mechanically reposition sagging tissue. Poly(L-lactide-co-ε-caprolactone) has long been used as absorbable sutures and as such has a well-demonstrated efficacy and safety profile. This biomaterial also has a well-defined biocompatibility and degradation profile. All studies reviewed in this paper show that thread lifting with absorbable barbed threads is an effective and well-tolerated procedure for correction of ptosis in facial and neck soft tissue and is associated with minor and reversible adverse effects. Most patients and surgeons consider the procedure satisfactory, with good to excellent results. This publication reviews the literature and clinical data supporting the degradation, absorbability, biocompatibility, safety, and effectiveness of these threads when used for tissue repositioning and facial rejuvenation procedures.

Fast scanning calorimetry (FSC) is an effective analytical tool to characterize the thermal properties of polymers. Heating rates up to 100 000 K/s allow studies at time scales inaccessible with conventional calorimeters, whose rates are typically less than about 0.5 K/s. Recent studies have successfully demonstrated methods for obtaining quantitative analysis of thermal properties of polymer samples using chip-based FSC. Therefore very small sample sizes, such as particles or nonwovens, can be characterized. In this study, we investigated the thermal properties of poly(L-lactide) PLLA with FSC compared to the results from standard DSC methods. PLLA specimens were fabricated via solution casting and needle electrospinning. The results suggest a significant influence of heating rates on the melting temperature of PLLA. The results show that different fabrication methods lead to changes in crystallinity and that FSC results are not completely comparable with standard DSC measurements.

Nonwoven tubular bioresorbable matrices with an inner diameter of 1.1 mm were obtained by electroforming from solutions of poly (L-lactide) (PLA). Matrices were implanted into the abdominal aorta of rats as a tissue-engineering vascular implant for a period of 2 days to 16 months and showed high biocompatibility, nontoxicity, and pronounced atrombogenic properties. The total implant patency was 93%. Morphometric analysis of the dynamics of population of the matrix with cells showed that, for all observation periods in the outer half of the matrix wall, the number of cells prevails, which indicates the migration of cells from the connective tissue capsule surrounding the matrix. It is shown that two parallel processes occur in the matrix wall: bioresorption of PLA fibers and the formation of connective tissue. Complete bioresorption of matrices with replacement by native tissues, as well as formation of the endothelial and subendothelial layers, took place over the 16 months of the experiment. By this time, all the experimental animals in the reconstruction zone revealed an aneurysmal expansion that did not lead to rupture of the implant. To prevent the development of such complications, it is necessary to develop a method for additional strengthening of the matrix wall.

As cartilage is incapable of self-healing upon severe degeneration because of the lack of blood vessels, cartilage tissue engineering is gaining importance in the treatment of cartilage defects. This study was designed to improve cartilage tissue regeneration by expressing tissue transglutaminase variant 2 (TGM2_v2) in mesenchymal stem cells (MSC) derived from bone marrow of rats. For this purpose, rat MSCs transduced with TGM2_v2 were grown and differentiated on three-dimensional polybutylene succinate (PBSu) and poly-l-lactide (PLLA) blend scaffolds. The transduced cells could not only successfully express the short form transglutaminase-2, but also deposited the protein onto the scaffolds. In addition, they could spontaneously produce cartilage-specific proteins without any chondrogenic induction, suggesting that TGM2_v2 expression provided the cells the ability of chondrogenic differentiation. PBSu:PLLA scaffolds loaded with TGM2_v2 expressing MSCs could be used in repair of articular cartilage defects.

Binary and ternary poly (L-lactide) (PLLA) based nanocomposites, containing nanolignin (1% wt.) and different metal oxide nanoparticles (0.5% wt., Ag2O, TiO2, WO3, Fe2O3 and ZnFe2O4) were realized ...

Skin wound healing is an intricate orchestration that involves different cell types, an extracellular matrix (ECM), cytokines, and growth factors. On the basis of the great benefits of cell-derived...

A total of 47 patients who underwent the craniofacial implantation of unsintered hydroxyapatite particles and a poly-L-lactide device were evaluated for clinical local findings and computed tomography (CT) images after about 6 months. Long-term follow-up of 3 patients was done from 5 to 11 years. The patients underwent CT imaging pre- and postoperatively, while local clinical examination was done upon follow-up. For the 3 patients who were followed up for more than 5 years, implant changes were evaluated by using CT. Computed tomography revealed 3 patients of dislocation, 2 patients of insufficient bone union, and 3 patients of implant breakage. All patients healed well with no complications requiring a secondary operation. The CT findings of the long-term cases revealed the following: a plate and screw were still present 5 years postsurgery (patient 1), mesh implants were completely resorbed after 9 years and 6 months (patient 2), and plates were almost resorbed after 11 years but some of their shapes remained (patient 3).The unsintered hydroxyapatite/poly-L-lactide device is useful in the maxillofacial region in terms of strength and radiographic contrast. However, since the absorption rate is slow, it is necessary to keep in mind its long-term radiographic detectability and the possibility of late-onset granuloma.

Poly l-Lactide (PLLA) composites with short flax fibers (from 0 to 10 wt/wt%)with close to maximum theoretical stiffness are prepared by melt-compounding and injection-molding followed by a two-step isothermal crystallization protocol that fully separates the nucleation and growth stages (Tammann). The use of fast chip scanning calorimetry for thermal characterization avoids the complicating issues of crystal reorganization during the cooling and heating steps between the isothermal stages. Flax fibers are very efficient and selective nucleating agents of PLLA favoring the ordered 𝜶 form. The resulting morphology exhibits trans-crystallization on the fibers surface, predominantly at fiber defects, with a clear reduction of crystal size and a very strong fiber matrix cohesion. Efficient nucleation further leads to a large reduction of the overall crystallization time. Avrami analysis evidences a reduction of crystal growth dimensionality, consistent with both optical and scanning electron microscopy. The high modulus of the composites is unambiguously related to the strong orientation of the fibers in the tensile direction, to their high aspect ratio and to the excellent matrix-fibers cohesion. On the other hand, the tensile strength and hardness appear isotropic within experimental uncertainty and are unfavorably influenced by the presence of the fibers and by the two-stage annealing.

Bioresorbable polymers composed of Poly(lactide), Poly(glycolide) and their related copolymers have become increasingly popular for the preparation of bone substitute constructs. In vitro tests assessing the degradative changes in physicochemical, mechanical, and biological properties of bioresorbable polymers are generally carried out at 37 °C, in pH 7.4 phosphate-buffered saline (PBS). However, long degradation times, varying from months to years make it difficult to assess these polymers at their late stages of degradation. An increased temperature accelerated degradation methodology, that simulates the long-term degradation of Poly( d , l -lactide-co-glycolide) and Poly( l -lactide-co-glycolide), has been validated in this study. Samples were degraded in PBS, under sterile conditions. Degradation temperatures of 47 °C, 57 °C and 70 °C were selected and compared to physiological temperature, 37 °C. At predetermined time intervals, samples were retrieved and evaluated for changes in mass, swelling, molecular weight, crystallinity, and thermal properties. The results from this study suggest that the degradation mechanism at elevated temperatures is similar to that observed at 37 °C. It is recommended that 47 °C is adopted by the research community to accelerate the degradation of these polymers. It is hoped the application of this methodology could be used as a valuable tool, prior to the assessment of the long-term biocompatibility of these polymers.

Background: Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been suggested as an alternative source of MSCs. However, the studies on its bone formation ability in oral maxillo-facial bone defect are rare. This study investigated the bone formation ability of recombinant human bone morphogenetic protein-7 (rhBMP-7)-induced hUC-MSCs combined with nano-hydroxyapatite/collagen/poly(L-lactide) (nHAC/PLA) in the back of nude mice and jaw bone defect of rabbit. Methods: The characteristics of hUC-MSCs were analyzed by plastic adherence, cell phenotype and multilineage differentiation potential. Cell proliferation was examined using a CCK-8 assay. Osteogenic differentiation was evaluated by quantitative calcium concentration, phosphorous concentration, alkaline phosphatase (ALP) activity, osteocalcin (OCN) concentration, mineral formation, and the mRNA levels of ALP, OCN and bone morphogenetic protein (BMP)-2. Scanning electron microscopy was used to observe cell adhesion, growth and differentiation. Bone formation was assessed by immunohistochemical staining, micro-CT and hematoxylin and eosin staining. Results: The isolated hUC-MSCs expressed CD105, CD90 and CD73, did not express CD45, CD34, CD11a and HLA-DR, exhibited self-renewal potential, and favored osteogenesis and adipogenesis. The exogenously-added rhBMP-7 attenuated the inhibitory effect of the serum-free osteogenic media (OMD) on the proliferation of hUC-MSCs combined with nHAC/PLA, increased the promoting effect of OMD on osteogenic differentiation of hUC-MSCs in two or three-dimensional culture, and enhanced its heterotopic bone formation and jaw bone defect repair abilities. Furthermore, the bone formation of in situ bone defect was significantly superior to heterotopic bone formation. Conclusions: That the microenvironment formed by the regenerative engineered constructs and the in situ bone defect microenvironment closely matched that of the bone tissue in its native state may be essential for sufficient and timely bone regeneration. The endogenously-produced BMPs may serve an important regulatory role in the process. These results paved the way for developing allogeneic hUC-MSCs-based constructs for clinical jaw bone regenerative therapeutic applications.

The purpose of this study is to report the outcomes of a series of orbital fracture repairs, their assessment with the Hess area ratio (HAR%), and the use of unsintered hydroxyapatite (HA) implants for reconstruction.This study involved 207 consecutive unilateral orbital fractures with symptomatic diplopia that underwent surgical repair within 28 days of injury. Ocular movement was measured presurgery and at 3 and 6 months postsurgery by Hess chart with calculation of the HAR%.Surgery was conducted on 207 patients (161 males and 46 females; mean age, 27.8 years) at a mean of 9.9 days postinjury and with a mean follow-up of 8.6 months. There were 160 patients with orbital floor fractures, 27 with medial wall fractures, and 20 with combined orbital medial wall and floor fractures, 135 of 207 patients had orbital blowout fractures, and 72 had orbital trap-door fractures. The HAR% improved significantly from a mean of 73.8% preoperatively to 92.7% postoperatively (P .01). Orbital fractures were reconstructed with either unsintered HA particles/poly l-lactide composite sheet (133 patients), a silicone silastic sheet (47 patients), a combination of sheets (15 patients), or without an implant (12 patients). There was no significant difference in the HAR% improvement between the different implants.Very good outcomes can be achieved with early orbital floor fracture repair surgery, which can be assessed preoperatively and postoperatively by HAR%. Unsintered HA/poly l-lactide composite sheets are an effective absorbable material for orbital floor fracture reconstruction.

Purpose The blood-brain barrier limits the application of idarubicin in the therapy of glioblastoma multiforme. Biodegradable, intracranial wafers with prolonged release may increase therapy efficiency. Methods Blank wafers, wafers containing 5% w/w and 10% w/w of idarubicin were formulated by solution casting from poly(L-lactide-co-glycolide) and poly(glycolide-co-ε-caprolactone). The following methods were used: NMR, GPC, DSC, FTIR, AFM, UV-VIS, and a viability and proliferation assay for idarubicin action (U87MG cell line). Results Wafers showed a surface with numerous immersions and hills. A lack of interactions between idarubicin and the copolymers was observed. The substance was entrapped in the matrix and released in two phases for all wafers with the appropriate bolus and maintenance dose. The burst effect was observed for all wafers, however, the biggest bolus for poly(L-lactide-co-glycolide) wafers containing 5% w/w of idarubicin was noted. The stable and steady degradation of poly(glycolide-co-ε-caprolactone) wafers containing 5% w/w of idarubicin ensures the most optimal release profile and high inhibition of proliferation. Conclusions Copolymer wafers with idarubicin are an interesting proposition with great potential for the local treatment of glioblastoma multiforme. The release rate and dose may be regulated by the amount and kind of wafers for various effects.

Vascular endothelial growth factor A (VEGF-A) is an important growth factor that plays a major role in angiogenesis. With different isoforms distributed in various tissues, the shortest isoform of VEGF-A is VEGF121, one of the physiologically functional variants next to VEGF165. It is well known that VEGF has a shorter half-life, and the stability of the protein must be considered in therapeutic aspects. Poly-l-lactide (PLA) microparticles can release the encapsulated protein in a sustained release mode. In this study, the VEGF121 gene was cloned and expressed in a prokaryotic expression system (Escherichia coli). The recombinant VEGF121 was encapsulated with PLA microparticles and studied in vitro and ex ovo for the sustained release mechanism. The PLA-VEGF microparticles and the recombinant VEGF121 were explored for their bioactivity in human umbilical vein endothelial cells (HUVEC). VEGF released in vitro from PLA microparticles on days 1, 20, and 30 showed remarkable biological activity compared to PBS-loaded PLA microparticles such as the ability of the cells to proliferate, migrate, and form tubes similar to recombinant VEGF121. Besides, PLA-VEGF microparticles and the recombinant VEGF121 were also tested for their proangiogenic action in embryonated eggs by chicken chorioallantoic membrane assay (CAM), and the effect was observed in both forms. This study suggests that PLA-loaded VEGF microparticles in a sustainable release format can be effectively used in proangiogenic therapy and reduce the adverse effects caused due to multiple dosages.

The novel synthesized tetra Poly (L-lactide) Carboxamide-cobalt (II) phthalocyanine (CoTPLLCAPc) is characterized by various spectral methods and as well as electrochemical investigations. The modified CoTPLLCAPc/MWCNTs/GCE was detecting the nanomolar concentration of Hydrazine in presence of L-Cysteine for detecting the separate cathodic peak potential, the modified electrode is determinations of multi-methods like cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chrono-amperometry (CA) with individual determinations of Hydrazine and L-Cysteine, the low detection limit of Hydrazine (CVs: 0.33, DPV: 0.033, CA: 6 nmol), L-Cysteine (CVs: 1.33, DPV: 1, CA: 3.33 nmol), Linear range; Hydrazine and L-cysteine were (CVs: 2-10, DPV: 1-10, CA: 5-50 nmol L-1), and high sensitivity (CVs: 1.299, DPV: 4.325, CA: 0.945 μAnM-1 cm-2 of hydrazine) and (CVs: 1.719, DPV: 4.193, CA: 0.770 μAnM-1 cm-2 of L-Cysteine), the CoTPLLCAPc/ MWCNTs/GCE was good reproducibility, repeatability, stability, and selectivity.

Electrospun poly(L-lactide) (PLLA) nonwoven represent potential options for biodegradable medical implants. They can be manufactured with high reproducibility and do offer the potential for chemical modification to alter matrix properties. In our study, we investigate the mechanical, thermal and morphological properties of PLLA fiber matrices. Fibrous nonwovens were fabricated from polymer solution by needle electrospinning. The polymer solutions were loaded with Triton X-100 (TX- 100), formic acid and tetraethyl ammonium chloride (TEAC) with respect to polymer weight. Morphology of the PLLA nonwoven scaffolds was examined with SEM. We performed uniaxial tensile tests and differential scanning calorimetry (DSC). Different concentrations of the additives TEAC, formic acid and Triton X-100 lead to strong changes regarding mechanical and thermal properties of the electrospun PLLA fiber matrices. In comparison with mechanical properties of established biological tissue materials, the results indicate the suitability for medical applications.

As a new type of intestinal stent, the MAO/PLLA/paclitaxel/Mg–Zn–Y–Nd alloy stent has shown good degradability, although its biocompatibility in vitro and in vivo has not been investigated in detail. In this study, its in vivo biocompatibility was evaluated by animal study. New Zealand white rabbits were implanted with degradable intestinal Mg–Zn–Y–Nd alloy stents that were exposed to different treatments. Stent degradation behavior was observed both macroscopically and using a scanning electron microscope (SEM). Energy dispersion spectrum (EDS) and histological observations were performed to investigate stent biological safety. Macroscopic analysis showed that the MAO/PLLA/paclitaxel/Mg–Zn–Y–Nd stents could not be located 12 days after implantation. SEM observations showed that corrosion degree of the MAO/PLLA/paclitaxel/Mg–Zn–Y–Nd stents implanted in rabbits was significantly lower than that in the PLLA/Mg–Zn–Y–Nd stent group. Both histopathological testing and serological analysis of in vivo biocompatibility demonstrated that the MAO/PLLA/paclitaxel/Mg–Zn–Y–Nd alloy stents could significantly inhibit intestinal tissue proliferation compared to the PLLA/Mg–Zn–Y–Nd alloy stents, thus providing the basis for designing excellent biodegradable drug stents.

Unicameral bone cysts are fluid-filled benign lesions that occur mostly in the long bones. Unicameral bone cysts in the pelvis are extremely rare. Continuous decompression using titanium or hydroxyapatite screws has been reported as a treatment. Screws made from a composite of unsintered hydroxyapatite particles and poly-l-lactide can be used for the treatment. An adolescent male patient presented with a unicameral bone cyst in the ilium extending to a region adjacent to the hip joint. As initial treatment, the cortex was fenestrated when the patient was 13 years old and β-tricalcium phosphate implanted. The cyst first reoccurred when the patient was 15 years old and again when he was 17 years old. During the most recent treatment, unsintered hydroxyapatite particles and poly-l-lactide composite screws were placed, and no recurrence was observed during 2 years of follow-up. The slow biodegradability and absorbability of the screws may allow continuous drainage of unicameral bone cysts.

Summary Introduction Bone defect reconstruction in orbital wall fractures with absorbable alloplastic such as the unsintered hydroxyapatite and poly L-lactide composite (u-HA/PLLA) system is gaining popularity. The u-HA/PLLA material has osteoconductive and osteosynthetic properties. However, quantitative, long-term outcome data after the use of u-HA/PLLA for orbital wall fractures are lacking. Patients and Methods We retrospectively analyzed 115 patients who underwent surgical repair of orbital wall fractures with a u-HA/PLLA sheet from 2011 to 2016. A chart review was performed, and the time-dependent changes at fracture sites were assessed by imaging. The immediate postoperative and the latest follow-up bony orbital volumes of the affected side were compared. Results Seventy patients were eligible for this study (mean age, 44.6 ± 22.1 years; 48 men and 22 women; mean follow-up period, 29.7 ± 12.8 months). Except for one case of hematoma, there were no postoperative wound complications. Of the 70 patients, 10 had postoperative diplopia and 2 had enophthalmos; these conditions were presumably caused by the extension and severity of the fracture. Satisfactory reduction in the entire orbital wall, without pathological changes, was demonstrated. There were no significant differences in the mean bony orbital volumes of the affected side immediately after surgery (24.774 ± 3.092 cm3) and at the latest follow-up (24.749 ± 3.205 cm3) (p = 0.756). Conclusion The u-HA/PLLA sheet is useful for orbital wall fracture reconstruction because of its desirable handling characteristics, initial mechanical strength, long-term maintenance of structural stability, radiopacity, and few associated complications. Future randomized controlled trials need to be performed to compare u-HA/PLLA with other conventional materials.

Introduction: Axonal regeneration after a sectioning lesion is variable and depends on the environmental conditions of the two end points. An important enzymatic action and an immune response occur at this point. The Schwann cell at the end of the proximal segment starts a rapid mitotic division in an attemptto locate the target tissue for the severed neuron. The capacity for axonal regeneration after a sectioning lesion is variable and depends on the environmental conditions of the two end points. Objective: To insulate the region of nerve regeneration from biological activities coming from foreign tissues, reducing the immune and enzymatic response and improving the healing conditions of the two end points. Methods: The sciatic nerves of the right paw of twenty WISTAR EPM rats were sectioned, with a gap of 5 to 8mm.In ten animals a 20mm Poly-L Lactide-Co P-Lactide tube involved both sectioned extremities,without nerve suture. After 6 months the animals were sacrificed, the nerve was dissected and photographed. The distal muscles of the paw were sent to histological examination. Results: All animals in which entubulation with Poly-L Lactide- Co P-Lactide was performed demonstrated an excellent nerveregeneration. Histological examination demonstrated complete muscle regeneration. In the animals not submitted to nerve entubulation no nerve regeneration was demonstrated and histological examination demonstrated severe muscle atrophy. Conclusions: Poly-L Lactide-Co P-Lactide entubulationdemonstrated satisfactory nerve regeneration without nerve suture after six months spam. Paw innervated muscles did not show any histological atrophic characteristics.

The aim of this study was to assess compositional changes in a forged-unsintered hydroxyapatite and poly-L-lactide (uHA/PLLA) mesh at 651 days after insertion into human body.A 35-year-old female patient had left tripod fracture, orbital medial wall and floor fracture, and superficial lateral palpebral ligament rupture. On the 9th posttrauma day, the tripod fracture was reduced and fixed with plates, and the orbital wall and floor were reconstructed with a resorbable mesh. The floor and medial wall were reconstructed with a trimmed mesh made of uHA/PLLA (Osterotrans-MX; Takiron Co, Umeda, Japan). On postoperative day 620, she complained of enophthalmos of left eye (right eye, 18 mm; left eye, 16 mm). Secondary reconstruction of the orbital floor was performed with an iliac bone graft 651 days after insertion. During the secondary operation, the uHA/PLLA mesh that had been previously inserted was removed. The mesh was removed and analyzed using gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR).The GPC revealed that the weight average molecular weight (Mw) decreased from 542,000 to 83,300 Da and the number average molecular weight (Mn) decreased from 124,000 to 20,200 Da in the specimen from the operation. In the postinsertion FTIR spectrum, weak 1648.6 and 1656.1/cm peaks newly appeared. The strong 1038/cm peak of the initial specimen changed slightly into a less strong 1041.8/cm peak.In conclusion, the reduced Mw and Mn in the postinsertion specimen suggest that uHA/PLLA has one of the favorable degradation properties. The newly appeared bands are thought to be carbon-carbon double bonds of alkenes.

We studied human bone healing characteristics and the histological osteogenic environment by using devices made of a composite of uncalcined and unsintered hydroxyapatite (u-HA) and poly-L-lactide (PLLA). In eight cases of fixation, we used u-HA/PLLA screws for maxillary alveolar ridge augmentation, for which mandibular cortical bone block was used in preimplantation surgery. Five appropriate samples with screws were evaluated histologically and immunohistochemically for runt-related transcription factor 2 (RUNX2), transcription factor Sp7 (Osterix), and leptin receptor (LepR). In all cases, histological evaluation revealed that bone components had completely surrounded the u-HA/PLLA screws, and the bone was connected directly to the biomaterial. Inflammatory cells did not invade the space between the bone and the u-HA/PLLA screw. Immunohistochemical evaluation revealed that many cells were positive for RUNX2 or Osterix, which are markers for osteoblast and osteoprogenitor cells, in the tissues surrounding u-HA/PLLA. In addition, many bone marrow&ndash, derived mesenchymal stem cells were notably positive for both LepR and RUNX2. The u-HA/PLLA material showed excellent bioactive osteoconductivity and a highly biocompatibility with bone directly attached. In addition, our findings suggest that many bone marrow&ndash, derived mesenchymal stem cells and mature osteoblast are present in the osteogenic environment created with u-HA/PLLA screws and that this environment is suitable for osteogenesis.

Current poly-l-lactide acid (PLLA) scaffolds have issues of inadequate mechanical strength leading to thrombosis formation. Designing a novel bioabsorbable PLLA stent with a novel structure and improved mechanical property is urgently needed. In this study, stent structure modification and optimization based on bioresorbable vascular scaffold Version 1.1 (BVS 1.1, Abbott Laboratories) were conducted. The mechanical property of the redesigned stent was studied using both computerized finite element analysis and experimental mechanical deformation testing, including radial strength (RS), acute recoil (AR), foreshortening (FS), and bending stiffness (BS). The simulated and experimental results showed that the mechanical properties of the modified structure were significantly improved (modified stent vs. BVS 1.1: RS: 2.25 vs. 1.29 N/mm; AR: 3.03 vs. 4.41%; FS: 1.13 vs. 6.89%; BS: 1.49 vs. 0.72 N mm2 ).

Obstructive salivary gland diseases are common conditions that arise following the disruption of the secretary ductal system and usually results in the swelling and pain of the affected gland(s). There has been an increase in the use of sialendoscopy for the treatment and diagnosis of obstructive salivary gland infection. If damage occurs to a duct or papilla following sialendoscopy, a stent may be necessary to prevent restenosis and for maintaining the salivary duct open after complete sialendoscopy. Currently, there are only non-biodegradable salivary duct stents available. The aim of the current study was to establish a methodology for the fabrication of a biodegradable poly-L-lactide (PLLA) salivary duct stent and to examine its function in an animal model. In the current study, PLLA was used to fabricate a salivary duct stent, which was compared with other commercially available non-biodegradable products. The mechanical tests revealed that the tensile strength of the PLLA stent was similar to that of the commercially available non-biodegradable stents. The Young's modulus, which measures the stiffness of a solid material, was significantly higher for the PLLA stent compared with the commercially available non-biodegradable stents. In addition, the current study demonstrated that the PLLA salivary duct stent was easily used with current sialendoscopy techniques, allowing accurate stent placement in an animal model.

Uncalcined/unsintered hydroxyapatite and poly-l-lactide-co-glycolide (u-HA/PLLA/PGA) is a new bioresorbable nanomaterial with superior characteristics compared with current bioresorbable materials, including appropriate mechanical properties, outstanding bioactive/osteoconductive features, and remarkably shorter resorption time. Nevertheless, the bone regeneration characteristics of this nanomaterial have not been evaluated in maxillofacial reconstructive surgery. In this study, we used a rat mandible model to assess the bone regeneration ability of u-HA/PLLA/PGA material, compared with uncalcined/unsintered hydroxyapatite and poly-l-lactide acid (u-HA/PLLA) material, which has demonstrated excellent bone regenerative ability. A 4-mm-diameter defect was created at the mandibular angle area in 28 Sprague Dawley male rats. The rats were divided into three groups: u-HA/PLLA/PGA (u-HA/PLLA/PGA graft + defect), u-HA/PLLA (u-HA/PLLA graft + defect), and sham control (defect alone). At 1, 3, 8, and 16 weeks after surgeries, the rats were sacrificed and assessed by micro-computed tomography, histological analysis with hematoxylin and eosin staining, and immunohistochemical analyses. The results confirmed that the accelerated bone bioactive/regenerative osteoconduction of u-HA/PLLA/PGA was comparable with that of u-HA/PLLA in the rat mandible model. Furthermore, this new regenerative nanomaterial was able to more rapidly induce bone formation in the early stage and had great potential for further clinical applications in maxillofacial reconstructive surgery.

Objective To determine the efficacy of a newly developed scaffold (col/β-TCP) in a preclinical rat model as compared with the gold standard treatment (autograft) and control scaffolds (PLLA/PCL). Design Fifty-six Sprague-Dawley rats were randomized into four experimental groups, and critical-sized alveolar defects (7 × 4 × 3 mm) were created in each animal. Group A was the blank defect group, group B received autograft, group C received col/β-TCP scaffolds, and group D received PLLA/PCL blend scaffolds to fill the bone defects. New bone formation was assessed radiomorphometrically, histomorphometrically, and molecular-biologically at 1 and 4 months following surgery. Results Radiomorphometrically, the best new bone volume rate at 1 month (43.7%) and 4 months (45.4%) was observed in the autograft group, and the difference was significantly higher than in the other three groups ( P ≤ .005, P ≤ .001, P ≤ .001 for 1 month and P = .004, P ≤ .001, P ≤ .001 for 4 months). Even though the new bone volume rate in the col/β-TCP group (21.5%) was higher than that of the PLLA/PCL group (18.2%), the difference was not significant ( P = .08). Molecular-genetic analysis revealed significantly higher BSP and ALP gene expression levels in the autograft and col/β-TCP groups than in the blank defect group ( P = .002 and P = .004). Conclusion The engineered tissue scaffolds described herein have great potential as an alternative treatment option when cost, donor region morbidity, and duration of hospitalization are considered.

Relevance of the work is due to the need for new materials that are used in medicine as a substitute for natural bone tissue injuries, fractures, etc. The aim of the work is to obtain composites with improved biocompatible properties based on poly-L-lactide (PLA) and hydroxyapatite (HA) and to perform pilot analysis of interaction PLA, HA, composite PLA-HA with primary human monocytes-derived macrophages in vitro. The pilot experiments using human primary monocytes cultivated on the surface of the samples demonstrated that PLA-HA can stimulate release of anti-inflammatory cytokines that indicates the presence of potential anti-inflammatory properties of the composites

The ringless spherulites of poly(L-lactide) (PLLA), fabricated via isothermal crystallization at temperatures of 100 °C and 140 °C (PLLA100 and PLLA140, respectively), were used to evaluate the effect of spherulites on MC3T3-E1 cell functions, including adhesion, proliferation, and differentiation. The atomic force microscopy (AFM) images indicated that PLLA100 presented a ridge width of 50–100 μm and a ride depth of 50–100 nm, whereas the values of PLLA140 were 25–50 μm and 100–350 nm, respectively. The cytoskeleton and nuclear alignment were observed on PLLA140, while no alignment was found on PLLA100. More interestingly, MC3T3-E1 cell proliferation and differentiation were also promoted significantly on PLLA140 compared with PLLA100. Our results, undoubtedly, provide a fundamental understanding regarding the effects of polymer spherulites on cell functions.

We present here a porous poly (L-lactide)/chitosan (PLLA/CS) composite scaffold with micro/nano-fiber hierarchical structure that was innovatively fabricated by combining 3D printing and thermally induced phase separation technology. Moreover, bioactive quercetin (Qu) was chosen to further functionalize the PLLA/CS scaffold with polydopamine (PDA) layer. The final results showed that the hydrophilicity and mechanical properties of the resulting PLLA/CS-D/Qu scaffold were obviously superior to those of the pure 3D printing PLLA scaffold. In vitro MC3T3-E1 cell experiments suggested that the introducing CS nanofiber network helped cells grow into the interior of the scaffold and promoted cell adhesion and proliferation. More importantly, the synergistic effect of the CS nanofiber network, PDA layer and especially sustain-released Qu, can endow the PLLA/CS-D/Qu scaffolds with not only excellent cell affinity and osteogenic activity, but also good anti-inflammatory property. Thus, the PLLA/CS-D/Qu scaffolds are expected to have good application prospects in the field of bone tissue engineering.

Fe3O4 nanoparticles were loaded into poly-l-lactide (PLLA) with concentrations of 2% and 5%, respectively, using an electrospinning method. In vivo animal experiments were then performed to evaluate the potential of the Fe3O4/PLLA nanofibrous material for bone tissue engineering applications. Bony defects with a diameter of 4 mm were prepared in rabbit tibias. Fe3O4/PLLA nanofibers were grafted into the drilled defects and histological examination and computed tomography (CT) image detection were performed after an eight-week healing period. The histological results showed that the artificial bony defects grafted with Fe3O4/PLLA nanofibers exhibited a visibly higher bone healing activity than those grafted with neat PLLA. In addition, the quantitative results from CT images revealed that the bony defects grafted with 2% and 5% Fe3O4/PLLA nanofibers, respectively, showed 1.9- and 2.3-fold increases in bone volume compared to the control blank sample. Overall, the results suggest that the Fe3O4/PLLA nanofibers fabricated in this study may serve as a useful biomaterial for future bone tissue engineering applications.

The use of biodegradable materials is gaining popularity in medicine, especially in orthopedic applications. However, preclinical evaluation of biodegradable materials can be challenging, since they are located in close contact with host tissues and might be implanted for a long period of time. Evaluation of these compounds requires biodegradability and biocompatibility studies and meticulous pathology examination. We describe 2 preclinical studies performed on Sprague-Dawley rats for 52 weeks, to evaluate clinical pathology, biocompatibility, biodegradability, and systemic toxicity after implantation of 2-layered films or saline-inflated balloon-shaped implants of downsized InSpace™ devices (termed “test device”). The test devices are made from a copolymer of poly-l-lactide-co-∊-caprolactone in a 70:30 ratio, identical to the device used in humans, intended for the treatment of rotator cuff tears. Intra-articular film implantation and subcutaneous implantation of the downsized device showed favorable local and systemic tolerability. Although the implanted materials have no inherent toxic or tumorigenic properties, one animal developed a fibrosarcoma at the implantation site, an event that is associated with a rodent-predilection response where solid materials cause mesenchymal neoplasms. This effect is discussed in the context of biodegradable materials along with a detailed description of expected pathology for biodegradable materials in long-term rodent studies.

The incidence of failed rotator cuff repairs remains high, especially in the setting of massive tears or revision repairs. The purpose of this study was to evaluate patient outcomes and repair integrity after augmentation with the repair patch, a poly-l-lactide synthetic polymer.Sixteen consecutive patients with massive or recurrent rotator cuff tears underwent open repair with synthetic poly-l-lactide patch augmentation. Two patients required the patch to bridge defects, and 1 patient retore after a motor vehicle accident and had revision surgery at another institution. The 13 remaining patients were retrospectively evaluated from 1.2 to 1.7 years (average, 1.5 years) after surgery by PENN, American Shoulder and Elbow Surgeons, and Single Assessment Numeric Evaluation scores. Magnetic resonance imaging was used to examine the integrity of the repair at a minimum of 1 year of follow-up.The mean age was 57.3 years (42-68 years). Five patients (38%) had an intact rotator cuff at the time of follow-up. The remaining patients (62%) had full-thickness tears. PENN scores significantly improved from a preoperative score of 50.9 to 77.6 (P.005). American Shoulder and Elbow Surgeons scores significantly improved from 32.8 to 74.2 (P = .0001). Single Assessment Numeric Evaluation scores at latest follow-up were 76.2.Poly-l-lactide repair patch augmentation of massive and recurrent large to massive rotator cuff tears demonstrates significant improvement in shoulder outcome measures for this difficult population, despite a retear rate of 62%. Further investigation with larger, prospective long-term studies is needed to determine whether this technique provides a true benefit compared with traditional, nonaugmented repair.

This work examined the effect of nucleating agents on the strain-induced crystallization of poly(L-lactide) (PLLA). Talc and poly(D-lactide) (PDLA) were used as the nucleating agents of PLLA. Wide angle X-ray scattering (WAXS) revealed that the original injection molded specimens of nucleated PLLA blends were free of PLLA a crystal. The structural evolution during uniaxial stretching of neat and nucleated PLLA above the glass transition temperature was investigated by in-situ WAXS. It was observed that the nucleating agents significantly accelerated the crystallization of PLLA during stretching. The accelerating effect for the PLLA crystallization during stretching increased in the following order: PDLA/talc > PDIA > talc. In step-strain measurements with a high stretching speed, the effect of nucleating agents on the crystallization of PLLA showed a strain-dependence. The enhancement of crystallization by nucleating agents was remarkable at 200% strain. However, with 500% strain, the strain-induced crystallization was dominant and the effect of nucleating agents on crystallization of PLLA was not obvious. The results were analyzed considering the nucleating effect of nucleating agents on PLLA. (C) 2015 Elsevier Ltd. All rights reserved.

In this work, a novel, effective and simple approach to largely improve the thermomechanical properties and heat distortion resistance of biodegradable poly(l-lactide) (PLLA) by using a new nucleating agent (NA), i.e., itself high-melting-point homocrystallites (hPLLA crystallites) is reported. Specially, hPLLA crystallites with a melting temperature (Tm) of 187 °C were introduced into the PLLA matrix with a lower Tm, i.e., 168 °C via simply melt blending at 170 °C which is between the Tms of the two PLLAs. Nonisothermal and isothermal crystallization results reveal that hPLLA crystallite is an efficient nucleating agent for PLLA. Also, hPLLA crystallites show much more prominently promoting effect on the crystallization rate of PLLA in comparison with two widely reported NAs for PLLA, talc and stereocomplex crystallites. Most importantly, this promoting effect is still efficient at very high cooling rate, leading to a crystallinity of 39.1% at a cooling rate of 100 °C/min, which can help to obtain high-c...

One of the major problems in orthopedic surgery is infection associated with implantation. The treatment is a very difficult and long-term process. A solution to this issue can be the use of implants which additionally constitute an antibiotic carrier preventing the development of an infection. Prototypes of biodegradable intramedullary nails made of three different composites with a poly( l -lactide) matrix were designed. The nails served as gentamicin sulfate (GS) carrier — an antibiotic commonly used in the treatment of osteomyelitis. The matrix was reinforced with carbon fibers (CF), alginate fibers (Alg) and magnesium alloy wires (Mg), as well as modified with bioactive particles of tricalcium phosphate (TCP) in various systems. In this way, novel, multi-phase and multifunctional degradable intramedullary nails were obtained. The tests demonstrated strong dependence between the type of the modifying phase introduced into the composite, and the rate of drug release. Introduction of gentamicin into the nail structure strengthened and prolonged antibacterial activity of the nails.

Electrospun scaffolds have been widely used in tissue engineering due to their similar structure to native extracellular matrices (ECM). However, one of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nano-sized pores, which inhibit cell infiltration into the scaffolds. To overcome this limitation, we approached to make layers which are consisted of cells onto the electrospun sheet and then tubular structure was constructed by rolling. We called this as 'Cell Matrix Engineering' because the electrospun sheets were combined with the cells to form one matrix. They maintained 3-D tubular structures well and their diameters were 4.1 mm (±0.1 mm). We compared the mechanical and biological properties of various vascular grafts with the electrospun PLCL sheets of different thickness. In these experiments, the vascular graft made with thin sheets showed a better cell proliferation and attachment than the grafts made with thick sheets because the thin layer allowed for more efficient mass transfer and better permeability than the thick layer. Culturing under physiological pulsatile flow condition was demonstrated in this work. These dynamic conditions provided the improved mass transport and aerobic cell metabolism. Therefore, the Cell Matrix Engineered vascular graft holds a great promise for clinical applications by overcoming the limitations associated with conventional scaffolds.

Here we report a novel bioactive electrospun mat based on poly(L-lactide-co-caprolactone) (PLLC) and collagen for wound dressing and sustained drug delivery of gentamicin. PLLC/collagen electrospun mat loaded with 10% gentamicin showed bioactivity for 15 days against Gram-positive and Gram-negative bacteria. The in vitro cell culture of 3T3 fibroblasts confirmed that these electrospun mat provide an increased specific interface area and hydrophilicity to enhance cell attachment, proliferation, and migration. The modified PLLC/collagen mat provided an excellent enhancement in properties of antibacterial wound dressings with a minimum in vitro toxicity and high potency for promoting wound healing stages.

Poly(l-lactide) electrospun mats with random and aligned fiber orientation and films have been produced with degrees of crystallinity ranging from 0 up to nearly 50%. The overall surface roughness is practically constant irrespective of the sampling areas (1 × 1 µm to 20 × 20 µm) for degrees of crystallinity below 30%, increasing for higher degrees of crystallinity for the larger sampling areas. Further, due to fiber confinement, surface roughness variations are smaller in electrospun mats. Samples with 50% of crystallinity show the lowest osteoblast and the highest fibroblast proliferation. Therefore, it is verified that higher roughness promotes lower osteoblast but higher fibroblast proliferation. The overall results indicate the relevant role of the sub-microenvironment variations associated to the microscale roughness in determining the different cell responses.

Fibrous materials of poly(l-lactide- co-d,l-lactide), poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol), and curcumin were prepared by electrospinning. The incorporation of poly(ethylene glycol) in the fibers caused a decrease in the mean fiber diameters down to 700 nm and in the water contact angle value, the latter being equal to 0 at poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol) 60/40 weight ratio. The water contact angle values of poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials considerably exceeded those of films of the same composition (approximately 120° as compared to approximately 95°, for electrospun mats and solution-cast films, respectively). Curcumin affected the thermal stability of the fibrous materials and the crystallinity degree of the polymers. The mechanical properties of the electrospun materials also depended on the composition of the polymer matrix and the amount of curcumin therein. In the curcumin-containing fibers, curcumin was found in the amorphous state, while higher antioxidant activity was exhibited by poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol)/curcumin fibrous materials. In vitro determination of the activated partial thromboplastin time and prothrombin time showed that poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials displayed anticoagulant activity. Antibacterial effect toward Staphylococcus aureus was manifested by the curcumin-containing mats.

Cheng-Hung Lee,1,2 Chia-Ying Yu,2 Shang-Hung Chang,1 Kuo-Chun Hung,1 Shih-Jung Liu,2 Chao-Jan Wang,3 Ming-Yi Hsu,3 I-Chang Hsieh,1 Wei-Jan Chen,1 Yu-Shien Ko,1 Ming-Shien Wen1 1Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital-Linkou, Tao-Yuan, Taiwan; 2Department of Mechanical Engineering, Chang Gung University, Tao-Yuan, Taiwan; 3Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Tao-Yuan, Taiwan Introduction: This work reports on the development of a biodegradable dual-drug-eluting stent with sequential-like and sustainable drug-release of anti-platelet acetylsalicylic acid and anti-smooth muscle cell (SMC) proliferative paclitaxel.Methods: To fabricate the biodegradable stents, poly-L-lactide strips are first cut from a solvent-casted film. They are rolled onto the surface of a metal pin to form spiral stents. The stents are then consecutively covered by acetylsalicylic acid and paclitaxel-loaded polylactide-polyglycolide nanofibers via electrospinning.Results: Biodegradable stents exhibit mechanical properties that are superior to those of metallic stents. Biodegradable stents sequentially release high concentrations of acetylsalicylic acid and paclitaxel for more than 30 and 60 days, respectively. In vitro, the eluted drugs promote endothelial cell numbers on days 3 and 7, and reduce the proliferation of SMCs in weeks 2, 4, and 8. The stents markedly inhibit the adhesion of platelets on days 3, 7, and 14 relative to a non-drug-eluting stent. In vivo, the implanted stent is intact, and no stent thrombosis is observed in the stent-implanted vessels without the administration of daily oral acetylsalicylic acid. Promotion of endothelial recovery and inhibition of neointimal hyperplasia are also observed on the stented vessels.Conclusion: The work demonstrates the efficiency and safety of the biodegradable dual-drug-eluting stents with sequential and sustainable drug release to diseased arteries. Keywords: sequential-like and sustainable release, biodegradable drug-eluting stents, poly-L-lactide, polylactide-polyglycolide, mechanical properties&nbsp