Printability and Critical Insight into Polymer Properties during Direct-Extrusion Based 3D Printing of Medical Grade Polylactide and Copolyesters.

Various 3D printing techniques currently use degradable polymers such as aliphatic polyesters to create well-defined scaffolds. Even though degradable polymers are influenced by the printing process, and this subsequently affects the mechanical properties and degradation profile, degradation of the polymer during the process is not often considered. Degradable scaffolds are today printed and cell-material interactions evaluated without considering the fact that the polymer change while printing the scaffold. Our methodology herein was to vary the printing parameters such as temperature, pressure, and speed to define the relationship between printability, polymer microstructure, composition, degradation profile during the process, and rheological behavior. We used high molecular weight medical-grade (co)polymers, poly(l-lactide-co-ε-caprolactone) (PCLA), poly(l-lactide-co-glycolide) (PLGA), and poly(d,l-lactide-co-glycolide) (PDLGA), with l-lactide content ranging from 25 to 100 mol %, for printing in an extrusion-based printer (3D Bioplotter). Optical microscopy confirmed that the polymers were printable at high resolution and good speed, until a certain degree of degradation. The results show also that printability can not be claimed just by optimizing printing parameters and highlight the importance of a careful analysis of how the polymer's structure and properties vary during printing. The polymers thermally decomposed from the first processing minute and caused a decrease in the average block length of the lactide blocks in the copolymers and generated lower crystallinity. Poly(l-lactide) (PLLA) and PCLA are printable at a higher molecular weight, less degradation before printing was possible, compared to PLGA and PDLGA, a result explained by the higher complex viscosity and more elastic polymeric melt of the copolymer containing glycolide (GA) and lactide (LA). In more detail, copolymers comprised of LA and ε-caprolactone (CL) formed lower molecular weight compounds over the course of printing, while the PLGA copolymer was more susceptible to intermolecular transesterification reactions, which do not affect the overall molecular weight, but cause changes in the copolymer microstructure. This results in a longer printing time for PLGA than PLLA and PCLA.

Poly(ε-caprolactone-co-p-dioxanone): a Degradable and Printable Copolymer for Pliable 3D Scaffolds Fabrication toward Adipose Tissue Regeneration.

The advancement of 3D printing technologies in the fabrication of degradable scaffolds for tissue engineering includes, from the standpoint of the polymer chemists, an urgent need to develop new materials that can be used as ink and are suitable for medical applications. Here, we demonstrate that a copolymer of ε-caprolactone (CL) with low amounts of p-dioxanone (DX) (15 mol %) is a degradable and printable material that suits the requirements of melt extrusion 3D printing technologies, including negligible degradation during thermal processing. It is therefore a potential candidate for soft tissue regeneration. The semicrystalline CL/DX copolymer is processed at a lower temperature than a commercial polycaprolactone (PCL), shaped as a filament for melt extrusion 3D printing and as porous and pliable scaffolds with a gradient design. Scaffolds have Young's modulus in the range of 60-80 MPa, values suitable for provision of structural support for damaged soft tissue such as breast tissue. SEM and confocal microscope indicate that the CL/DX copolymer scaffolds support adipose stem cell attachment, spreading, and proliferation.

Analytical review on the biocompatibility of surface-treated Ti-alloys for joint replacement applications.

INTRODUCTION: With the advancement of joint replacements such as total hip replacement (THR), Titanium (Ti) and its alloys are widely used as implant materials. The bearing surface of Ti improves the longevity of implants. In this perception, researchers design a Ti-alloy that increases the wear and corrosion resistance to enhance osteogenesis and mechanical stability. AREAS COVERED: : This paper is dedicated to finding the major causes of the failure of THR. Further, this paper provides an overview of the application of metallic alloys and their influencing factors that influence biocompatibility. The most contributing part of this paper focuses on the post-treatment impact on Ti-alloys biocompatibility. EXPERT OPINION: This paper revealed and discussed that Ti alloys' biocompatibility for orthopedic applications mainly depends on antibacterial activities that decide tissue-implant compatibility. Therefore, performing surface treatment enhances the biocompatibility of Ti alloys. It was also observed that more water contact angle (WCA) induces bacterial growth and enhances cell adhesion. In contrast, the treated surface increases the antibacterial activities at lower WCA. Surface heat treatment with sintering or micro-arc oxidation achieves suitable antibacterial or antimicrobial activities.

Understanding of how the properties of medical grade lactide based copolymer scaffolds influence adipose tissue regeneration: Sterilization and a systematic in vitro assessment.

Aliphatic polyesters are the synthetic polymers most commonly used in the development of resorbable medical implants/devices. Various three-dimensional (3D) scaffolds have been fabricated from these polymers and used in adipose tissue engineering. However, their systematic evaluation altogether lacks, which makes it difficult to select a suitable degradable polymer to design 3D resorbable implants and/or devices able to effectively mimic the properties of adipose tissue. Additionally, the impact of sterilization methods on the medical devices, if any, must be taken into account. We evaluate and compare five different medical-grade resorbable polyesters with l-lactide content ranging from 50 to 100 mol% and exhibiting different physiochemical properties depending on the comonomer (d-lactide, ε-caprolactone, glycolide, and trimethylene carbonate). The salt-leaching technique was used to prepare 3D microporous scaffolds. A comprehensive assessment of physical, chemical, and mechanical properties of the scaffolds was carried out in PBS at 37 °C. The cell-material interactions and the ability of the scaffolds to promote adipogenesis of human adipose tissue-derived stem cells were assessed in vitro. The diverse physical and mechanical properties of the scaffolds, due to the different composition of the copolymers, influenced human adipose tissue-derived stem cells proliferation and differentiation. Scaffolds made from polymers which were above their glass transition temperature and with low degree of crystallinity showed better proliferation and adipogenic differentiation of stem cells. The effect of sterilization techniques (electron beam and ethylene oxide) on the polymer properties was also evaluated. Results showed that scaffolds sterilized with the ethylene oxide method better retained their physical and chemical properties. Overall, the presented research provides (i) a detailed understanding to select a degradable polymer that has relevant properties to augment adipose tissue regeneration and can be further used to fabricate medical devices/implants; (ii) directions to prefer a sterilization method that does not change polymer properties.

Exploration of an innovative draw solution for a forward osmosis-membrane distillation desalination process.

Forward osmosis (FO) has emerged as a viable technology to alleviate the global water crisis. The greatest challenge facing the application of FO technology is the lack of an ideal draw solution with high water flux and low reverse salt flux. Hence, the objective of this study was to enhance FO by lowering reverse salt flux and maintaining high water flux; the method involved adding small concentrations of Al2(SO4)3 to a MgCl2 draw solution. Results showed that 0.5 M MgCl2 mixed with 0.05 M of Al2(SO4)3 at pH 6.5 achieved a lower reverse salt flux (0.53 gMH) than that of pure MgCl2 (1.55 gMH) using an FO cellulose triacetate nonwoven (CTA-NW) membrane. This was due possibly to the flocculation of aluminum hydroxide in the mixed draw solution that constricted membrane pores, resulting in reduced salt diffusion. Moreover, average water fluxes of 4.09 and 1.74 L/m2-h (LMH) were achieved over 180 min, respectively, when brackish water (5 g/L) and sea water (35 g/L) were used as feed solutions. Furthermore, three types of membrane distillation (MD) membranes were selected for draw solution recovery; of these, a polytetrafluoroethylene membrane with a pore size of 0.45 µm proved to be the most effective in achieving a high salt rejection (99.90%) and high water flux (5.41 LMH) in a diluted draw solution.

Nanoscale Topography on Black Titanium Imparts Multi-biofunctional Properties for Orthopedic Applications.

We have developed a chlorine based reactive ion etching process to yield randomly oriented anisotropic nanostructures that render the titanium metal surface 'black' similar to that of black silicon. The surface appears black due to the nanostructures in contrast to the conventional shiny surface of titanium. The nanostructures were found to kill bacteria on contact by mechanically rupturing the cells as has been observed previously on wings of certain insects. The etching was optimized to yield nanostructures of ≈1 µm height for maximal bactericidal efficiency without compromising cytocompatibility. Within 4 hours of contact with the black titanium surface, 95% ± 5% of E. coli, 98% ± 2% of P. aeruginosa, 92% ± 5% of M. smegmatis and 22% ± 8% of S. aureus cells that had attached were killed. The killing efficiency for the S. aureus increased to 76% ± 4% when the cells were allowed to adhere up to 24 hours. The black titanium supported the attachment and proliferation of human mesenchymal stem cells and augmented osteogenic lineage commitment in vitro. Thus, the bioinspired nanostructures on black titanium impart multi-biofunctional properties toward engineering the next-generation biomaterials for orthopedic implants.

Curcumin eluting nanofibers augment osteogenesis toward phytochemical based bone tissue engineering.

Curcumin is a phenolic compound isolated from Curcuma longa that is known to exhibit wide ranging biological activity including potential benefits for bone growth. The aim of this work was to engineer curcumin eluting tissue scaffolds and investigate their potential use in bone tissue regeneration. We prepared curcumin loaded poly(ε-caprolactone) (PCL) nanofibers by electrospinning. Morphological characterization of the nanofibers revealed that the average diameter of neat fibers and that of fibers with 1 wt% and 5 wt% curcumin is 840 ± 130 nm, 827 ± 129 nm and 680 ± 110 nm, respectively. Fourier transformation infrared spectroscopy and 1H nuclear magnetic resonance confirmed the successful loading of the drug in fibers. In aqueous medium, the fibers released ≈18% of the encapsulated drug in 3 d and ≈60% in 9 d. The cell response to the curcumin loaded nanofibers was assessed using MC3T3-E1 pre-osteoblasts. Cell proliferation was moderated with increased loading of curcumin and was 50% lower on the fibers containing 5% curcumin at day 10 than the control fibers. Osteogenesis was confirmed by assaying the expression of alkaline phosphatase and staining of mineral deposits by Alizarin red stain, which were both markedly higher for 1% curcumin compared to neat polymer but lower for 5% curcumin. Mineral deposition was also confirmed chemically by Fourier transform infrared spectroscopy. These results were corroborated by increased gene and protein expression of known osteogenic markers in 1% curcumin. Thus, controlled release of curcumin from polymer scaffolds is a promising strategy for bone tissue regeneration.

Modulated in Vitro Biocompatibility of a Unique Cross-Linked Salicylic Acid-Poly(ε-caprolactone)-Based Biodegradable Polymer.

Herein, we report the development of a unique architecture by chemically cross-linking salicylic acid (SA)-based poly(anhydride ester) onto a biodegradable amine-functionalized poly(caprolactone) (PCL), using lactic acid as a spacer. The ester and amide linkages in the SA-PCL polymer, synthesized through melt condensation, were confirmed by NMR and FT-IR spectroscopic techniques. The enzymatic and nonenzymatic hydrolytic degradation profile exhibited linear degradation kinetics over an extended time period (>5 weeks). The compatibility and growth of C2C12 myoblast cells were found to be significantly improved on the fast-degrading SA-PCL substrates compared to those over neat PCL and amine-functionalized PCL. Further, the decreased red blood cell damage, illustrated by 0.39% hemolysis activity and a minimal number of platelet adhesion on a SA-PCL polymeric surface confirmed good hemocompatibility of the as-synthesized polymer. Together with a moderate bactericidal property, the spectrum of properties of this novel polymer can be attributed to the synergistic effect of the presence of chemical moieties of SA and amine groups in PCL. In summary, it is considered that a SA-PCL-based cross-linked composite can be utilized as a new biodegradable polymer.

Unimpeded permeation of water through biocidal graphene oxide sheets anchored on to 3D porous polyolefinic membranes.

3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and hot-pressed samples revealed a clear picture as to how the morphology develops and coarsens over a function of time during post-processing operations like compression molding. The coarsening of PE/PEO blends was traced using X-ray micro-computed tomography and scanning electron microscopy (SEM) of annealed blends at different times. It is now understood from X-ray micro-computed tomography that by the addition of a compatibilizer (here lightly maleated PE), a stable morphology can be visualized in 3D. In order to anchor biocidal graphene oxide sheets onto these 3D porous membranes, the PE membranes were chemically modified with acid/ethylene diamine treatment to anchor the GO sheets which were further confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and surface Raman mapping. The transport properties through the membrane clearly reveal unimpeded permeation of water which suggests that anchoring GO on to the membranes does not clog the pores. Antibacterial studies through the direct contact of bacteria with GO anchored PE membranes resulted in 99% of bacterial inactivation. The possible bacterial inactivation through physical disruption of the bacterial cell wall and/or reactive oxygen species (ROS) is discussed herein. Thus this study opens new avenues in designing polyolefin based antibacterial 3D porous membranes for water purification.

Comparison of Opinion Referendum of Medical and Dental Postgraduates Towards Plagiarism in Bhopal - Central India.

OBJECTIVE: To evaluate awareness and attitude towards plagiarism of postgraduates of health fraternity in Bhopal, Central India. STUDY DESIGN: Across-sectional survey. PLACE AND DURATION OF STUDY: People's University, Bhopal, Madhya Pradesh, India, from January to March 2014. METHODOLOGY: A total of 164 postgraduates, medical (n = 80) and dental postgraduates (n = 84) were included in the study. A standard pre-tested self-administered questionnaire assessing positive, negative and subjective norms towards plagiarism was the assessing tool. Data was captured through distribution of the instrument and collected as scheduled from the study participants. The distribution of scores based on the responses to the individual questions in each dimension between the groups were compared using Mann-Whitney U-test. RESULTS: Among dental and medical postgraduates the median values for the questions under positive attitude was 34.0 and 32.0, negative attitude was 21.5 and 19, subjective norms was 29.0 and 27.5 respectively. The difference in the opinion regarding positive attitude was found to be statistically significant in between the groups (p < 0.05). CONCLUSION: Overall plagiarism was favored more by dental students as compared to medical students. Moreover, inadequate level of knowledge and awareness was observed in both the streams. Efforts should be undertaken to motivate health professionals to instill honest behavior in order to preserve the intellectual property right.

Influence of barium substitution on bioactivity, thermal and physico-mechanical properties of bioactive glass.

Barium with low concentration in the glasses acts as a muscle stimulant and is found in human teeth. We have made a primary study by substituting barium in the bioactive glass. The chemical composition containing (46.1-X) SiO2--24.3 Na2O-26.9 CaO-2.6 P2O5, where X=0, 0.4, 0.8, 1.2 and 1.6mol% of BaO was chosen and melted in an electric furnace at 1400±5°C. The glasses were characterized to determine their use in biomedical applications. The nucleation and crystallization regimes were determined by DTA and the controlled crystallization was carried out by suitable heat treatment. The crystalline phase formed was identified by using XRD technique. Bioactivity of these glasses was assessed by immersion in simulated body fluid (SBF) for various time periods. The formation of hydroxy carbonate apatite (HCA) layer was identified by FTIR spectrometry, scanning electron microscope (SEM) and XRD which showed the presence of HCA as the main phase in all tested bioactive glass samples. Flexural strength and densities of bioactive glasses have been measured and found to increase with increasing the barium content. The human blood compatibility of the samples was evaluated and found to be pertinent.

Assessment of periodontal status among eunuchs residing in Bhopal city, Madhya Pradesh, India: a cross-sectional study.

AIM: To assess the periodontal status among eunuchs residing in Bhopal city, Madhya Pradesh, India. MATERIALS AND METHODS: Based on convenient non-probability snow ball sampling technique, all the self-identifi ed eunuchs residing in the city of Bhopal along with a matched control consisting of cross section of the general population residing in the same locality where these eunuchs live was examined to assess the periodontal status of the population by using WHO oral health assessment proforma 1997. All the obtained data was entered into a personal computer on Microsoft excel sheet and analyzed by using a software; SPSS version 20. Data comparison was done by applying chi square test, ANOVA and multiple logistic regression analysis. RESULTS: A total of 639 subjects comprised of 207 eunuchs, 218 males and 214 females. The overall gingival and periodontal disease prevalence was 87.3% with calculus and shallow pocket contributing a major part i.e., 67%. Among study participants, 56.9% males were having highest prevalence for calculus. Whereas, eunuchs were having highest prevalence for bleeding (17.4%), shallow pocket (22.7%) and deep pocket (9.7%). However, highest of 19.7% males and 10.1% eunuchs were having attachment loss of 4-5 mm and 6-8 mm respectively. However, 6.3% eunuchs were having attachment loss of 12 mm or more. CONCLUSION: The results of the current study showed poor periodontal status among eunuch population with most of the population requiring simple therapy. This indicates that comprehensive oral hygiene instruction and dental prophylaxis need to be initiated.

Oral health-related knowledge, attitude and practices among eunuchs (hijras) residing in Bhopal City, Madhya Pradesh, India: A cross-sectional questionnaire survey.

BACKGROUND: The current cross-sectional questionnaire survey was conducted to assess the oral health-related knowledge, attitude and practices among eunuchs (hijras) residing in Bhopal city, Madhya Pradesh, India. MATERIALS AND METHODS: Based on a convenient non-probability snow ball sampling technique, all the self-identified eunuchs residing in the city of Bhopal who were present at the time of study and who fulfilled the selection criteria were approached. A cross section of the general population was also surveyed. An interviewer-based, predesigned, structured, close-ended 18-item questionnaire that had been designed based on the primary objective of the study was used. All the obtained data were analyzed using software, Statistical Package for Social Science version 20. RESULTS: According to 188 (86.2%) males, 187 (87.4%) females and 168 (81.2%) eunuchs, good oral health can improve the general health. Most of the study participants including 211 (98.6%) females, 210 (96.3%) males and 205 (99%) eunuchs use either tooth paste or tooth powder to clean their teeth. While, a majority of eunuchs, i.e., 113 (54.6%), were having habit of chewing smokeless tobacco containing products such as betel nut, betel quid, gutkha, etc., The difference in use of tobacco products was statistically significant. CONCLUSION: The information presented in this study adds to our understanding of the common oral hygiene practices which are performed among eunuch population. Efforts to increase the awareness of oral effects of tobacco use and to eliminate the habit are needed to improve oral and general health of this population.