Stereolithography printing of bone scaffolds using biofunctional calcium phosphate nanoparticles

Calcium phosphate(CaP)has been widely used for bone defect repair due to good biocompatibility and osteoconductivity.Additive manufacture of calcium phosphate bioceramics with tailored architectures and improved mechanical properties has recently attracted great attention.Herein,calcium phosphate nanoparticles with the size of~89-164 nm were synthesized by the hydrothermal treatment of amorphous calcium phosphate(ACP)precursors at 180°C for 24 h.Biofunctional elements including Mg,Sr and Zn have been doped into these calcium phosphate nanoparticles.Our results revealed that Mg^(2+)ions played critical roles in formation of whitlockite-type calcium phosphate(not hydroxyapatite)from ACP precursors.Moreover,gyroid scaffolds with bionic triply periodic minimal surface structures were fabricated using stereolithography printing of these calcium phosphate nanoparticles,which are likely used as biofunctional scaffolds for bone repair.

Preparation of Biodegradable Mg/β-TCP Biofunctional Gradient Materials by Friction Stir Processing and Pulse Reverse Current Electrodeposition

Mg alloys,as a new generation of biodegradable bone implant materials,are facing two tremendous challenges of enhancing strength and reducing degradation rate in physiological environment to meet clinical needs.In this study,tricalcium phosphate(β-TCP)particles were dispersed in Mg–2 Zn–0.46 Y–0.5 Nd alloy by friction stir processing(FSP)to produce Mg-based functional gradient materials(Mg/β-TCP FGM).On the surface of Mg/β-TCP FGM,the hydroxyapatite(HA)coating was prepared by electrodeposition.The effects of FSP and electrochemical parameter on the microstructure,microhardness,bonding strength and corrosion performance of the Mg/β-TCP FGM were investigated.After four passes of FSP,a uniform and fine-grained structure was formed in Mg/β-TCP and the microhardness increased from 47.9 to 76.3 HV.Compared to the samples withoutβ-TCP,the bonding strength of the Mg/β-TCP FGM increased from 23.1±0.462 to 26.3±0.526 MPa and the addition of degradableβ-TCP contributed to the in situ growth of HA coating.The thickness of HA coating could be dominated by controlling the parameters of electrodeposition.According to the results of immersion tests and electrochemical tests in simulated body fluid,it indicated that the degradation rate of the Mg/β-TCP FGM could be adjusted.

Inorganic Nanoparticles Conjugated with Biofunctional Molecules

1 Results We have attempted to conjugate inorganic nanoparticles with biofunctional molecules.Recently we were quite successful in demonstrating that a two-dimensional inorganic compound like layered double hydroxide (LDH),and natural and synthetic clays can be used as gene or drug delivery carriers1-4.To the best of our knowledge,such inorganic vectors are completely new and different from conventionally developed ones such as viruses and cationic liposomes,those which are limited in certain cases of ap...

Biofunctional magnesium coating of implant materials by physical vapour deposition

The lack of bioactivity of conventional medical materials leads to low osseointegration ability that may result in the occurrence of aseptic loosening in the clinic.To achieve high osseointegration,surface modifications with multiple biofunctions including degradability,osteogenesis,angiogenesis and antibacterial properties are required.However,the functions of conventional bioactive coatings are limited.Thus novel biofunctional magnesium(Mg)coatings are believed to be promising candidates for surface modification of implant materials for use in bone tissue repair.By physical vapour deposition,many previous researchers have deposited Mg coatings with high purity and granular microstructure on titanium alloys,polyetheretherketone,steels,Mg alloys and silicon.It was found that the Mg coatings with high-purity could considerably control the degradation rate in the initial stage of Mg alloy implantation,which is the most important problem for the application of Mg alloy implants.In addition,Mg coating on titanium(Ti)implant materials has been extensively studied both in vitro and in vivo,and the results indicated that their corrosion behaviour and biocompatibility are promising.Mg coatings continuously release Mg ions during the degradation process,and the alkaline environment caused by Mg degradation has obvious antibacterial effects.Meanwhile,the Mg coating has beneficial effects on osteogenesis and osseointegration,and increases the new bone-regenerating ability.Mg coatings also exhibit favourable osteogenic and angiogenic properties in vitro and increased long-term bone formation and early vascularization in vivo.Inhibitory effects of Mg coatings on osteoclasts have also been proven,which play a great role in osteoporotic patients.In addition,in order to obtain more biofunctions,other alloying elements such as copper have been added to the Mg coatings.Thus,Mg-coated Ti acquired biofunctions including degradability,osteogenesis,angiogenesis and antibacterial properties.These novel multi-functional Mg coatings are expected to significantly enhance the long-term safety of bone implants for the benefit of patients.This paper gives a brief review of studies of the microstructure,degradation behaviours and biofunctions of Mg coatings,and directions for future research are also proposed.

Interactive association between processing induced molecular structure changes and nutrient delivery on a molecular basis,revealed by cutting-edge vibrational biomolecular spectroscopy

Background:This study was conducted to determine protein molecular structure profiles and quantify the relationship between protein structural features and protein metabolism and bioavailability of blend pel eted products(BPP)based on co-products(canola or carinata)from processing with different proportions of pulse pea screenings and lignosulfonate chemical compound.Method:The protein molecular structures were determined using the non-invasive advanced vibrational molecular spectroscopy(ATR-FT/IR)in terms of chemical structure and biofunctional groups of amides(ⅠandⅡ),α-helix andβ-sheet.Results:The results showed that increasing the level of the co-products in BPP significantly increased the spectral intensity of the amide area and amide height.The products exhibited similar protein secondaryα-helix toβ-sheet ratio.The protein molecular structure profiles(amidesⅠandⅡ,α-helix toβ-sheet)were highly associated with protein degradation kinetics and intestinal digestion.In conclusion,the non-invasive vibrational molecular spectroscopy(ATR-FT/IR)could be used to detect inherent structural make-up characteristics in BPP.Conclusion:The molecular structural features related to protein biopolymer were highly associated with protein utilization and metabolism.

Production and Evaluation of Antimicrobial Microcapsules with Essential Oils Using Complex Coacervation

Nowadays, the needs and requirements to avoid infections during surgical operations, require to be more imaginative than ever. The one-use textiles substrates that are used in hospitals can be, also, a way to transport the antibacterial effect around the own building. This is the main objective of this work;to use clothes and textiles surfaces as antibacterial systems using natural components. Microencapsulation has shown in several occasions the effectivity to protect and vehiculize active principles that can be used for medical treatments. In this case, essential oils have been used as antimicrobial agent, that when combined with shell polymers based on Chitosan of different molecular weight distribution and Arabic gum, allows them to act against Gram (+) and Gram (−) bacteria. The study of the efficiency of all the samples made gave a high value due to its character similar to hydrogels, while the determination of solids was higher when it was a question of samples made with a low molecular weight. The essential oil used has a very volatile character formed by more than 40 components and with the help of FT-IR and TGA it has been possible to corroborate that all its components were encapsulated. The impregnation of the different samples to the tissue was successful and allowed the antibacterial study to be carried out, which was carried out in duplicate on each sample and demonstrated that they have bacterial activity.

Influence of Chitosan Characteristics in the Microencapsulation of Essential Oils

The fight against nosocomial infections in hospitals, has promoted the use of microencapsulated essential oils on medical wearing uniforms. These types of microcapsules can be improved with the use of antimicrobial polymers in the shell structure. Chitosan is one of the most used biopolymers and the effectiveness of the treatment can be increased with the combination of different molecular weight chains of chitosan. This modification in the composition of shell structure allows controlling the rate of hydrolysis and, therefore the amount of its cationic form. The main objective of this work is to define a methodology to get microcapsules with different shell compositions, using surfactants as stabilizers in their first step. Once they have been obtained, these microcapsules will be fixed into textile substrates with the objective to use these tissues as surgical and medical clothes to spread the antibacterial effect, in sanitary staff, as well as in the own patient. In the process of microencapsulation the molecular weight distribution of polymers, influences strongly the delivery mechanisms of the active principle, as well as the chemical characteristics of the textile substrate used in every case. In this work, several chitosan biopolymers have been checked. Structural changes in the stabilization first step and the influence of the cross-linking extension have been related with the final antibacterial effect when fixed on cotton substrates.

Research and development of Cordyceps in Taiwan

Cordyceps is treasured entomopathogenic fungi that have been used as antitumor,immunomodulating,antioxidant,and pro-sexual agent.Cordyceps,also called DongChongXiaCao in Chinese,Yartsa Gunbu(Tibetan),means winter worm-summer grass.Natural Cordyceps sinensis with parasitic hosts is difficult to be collected and the recent findings on its potential pharmacological functions,resulted in skyrocketing prices.Therefore,finding a mass-production method or an alternative for C.sinensis products is a top-priority task.In this review,we describe current status of Cordyceps research and its recent developments in Taiwan.The content and pharmacological activities of four major industrial species of Cordyceps(C.sinensis,Cordyceps militaris,Cordyceps cicadae and Cordyceps sobolifera)used in Taiwan,were reviewed.Moreover,we highlighted the effect of using different methods of fermentation and production on the morphology and chemical content of Cordyceps sp.Finally,we summarized the bottle-necks and challenges facing Cordyceps research as well as we proposed future road map for Cordyceps industry in Taiwan.

RGD peptide and graphene oxide co-functionalized PLGA nanofiber scaffolds for vascular tissue engineering

In recent years,much research has been suggested and examined for the development of tissue engineering scaffolds to promote cellular behaviors.In our study,RGD peptide and graphene oxide(GO)co-functionalized poly(lactide-co-glycolide,PLGA)(RGD-GO-PLGA)nanofiber mats were fabricated via electrospinning,and their physicochemical and thermal properties were characterized to explore their potential as biofunctional scaffolds for vascular tissue engineering.Scanning electron microscopy images revealed that the RGD-GO-PLGA nanofiber mats were readily fabricated and composed of randomoriented electrospun nanofibers with average diameter of 558nm.The successful co-functionalization of RGD peptide and GO into the PLGA nanofibers was confirmed by Fourier-transform infrared spectroscopic analysis.Moreover,the surface hydrophilicity of the nanofiber mats was markedly increased by co-functionalizing with RGD peptide and GO.It was found that the mats were thermally stable under the cell culture condition.Furthermore,the initial attachment and proliferation of primarily cultured vascular smoothmuscle cells(VSMCs)on the RGD-GO-PLGA nanofibermats were evaluated.It was revealed that the RGD-GO-PLGA nanofibermats can effectively promote the growth of VSMCs.In conclusion,our findings suggest that the RGD-GO-PLGA nanofiber mats can be promising candidates for tissue engineering scaffolds effective for the regeneration of vascular smooth muscle.