Basic study of corn protein, zein, as a biomaterial in tissue engineering, surface morphology and biocompatibility

The zein films, were prepared for culturing human liver cells (HL-7702) and mice fibroblast cells (NIH3T3), while the Corning microplate and polylactic acid (PLA) were chosen as controls. The surface morphology of zein films prepared by two different methods was studied by scanning electron microscope (SEM), which revealed that the zein films were composed of particles of diameter 100-500 and 500-2500 nm, respectively. The biocompatibility of zein films was assessed by attachment, extensibility and proliferation of cells on them. Our study indicated that over 60% of both HL-7702 cells and NIH3T3 cells could attach to the Corning microplate, zein films and PLA at 3h after seeding. The concentration and particle sizes for preparing zein films did not seem to affect the proliferation of the cells tested. There were no significant differences in the proliferation of both HL-7702 cells and NIH3T3 cells between the Corning microplate and two kinds of zein films, except that the zein film composed of smaller particles at the lowest concentration exhibited a very good ability for proliferation of both the cells, while PLA was a poor matrix in the latter period of the cell proliferation. This preliminary study demonstrates that zein is a promising biomaterial with good biocompatibility for the development of tissue engineering.     

Effect of surface treatment on the biocompatibility of microbial polyhydroxyalkanoates.

The biocompatibility of microbial polyesters polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) were evaluated in vitro. The mouse fibroblast cell line L929 was inoculated on films made of PHB, PHBHHx and their blends, polylactic acid (PLA) as control. It was found that the growth of the cells L929 was poor on PHB and PLA films. The viable cell number ranged from 8.8 x 10(2) to 1.8 x 10(4)/cm2 only. Cell growth on the films made by blending PHB and PHBHHx showed a dramatic improvement. The viable cell number observed increased from 9.7 x 10(2) to 1.9 x 10(5) on a series of PHB/PHBHHx blended film in ratios of 0.9/0.1:0/1, respectively, indicating a much better biocompatibility in the blends contributed by PHBHHx. Biocompatibility was also strongly improved when these polymers were treated with lipases and NaOH, respectively. However, the effects of treatment were weakened when PHBHHx content increased in the blends. It was found that lipase treatment had more increased biocompatibility than NaOH. After the treatment biocompatibility of PHB was approximately the same as PLA, while PHBHHx and its dominant blends showed improved biocompatibility compared to PLA.     

Materials from Titanium—Cobalt Alloys for Hybrid Implants

We proposed a new method to increase the biocompatibility of porous materials that were synthesized from titanium and cobalt allows by the method of self-propagating high-temperature synthesis. This method suggested the introduction of calcium hydroxyapatite into the reaction mixture. Administration of calcium hydroxyapatite into the reaction mixture had a modifying effect on the structure and surface of the pore space and biocompatibility of composite materials. Administration of calcium hydroxyapatite crystals was followed by a significant decrease in the size of pores and appearance of water-soluble fractions, which inhibited the activity of cells. However, treatment with amorphous nanodispersed calcium hydroxyapatite increased the biocompatibility and adhesiveness of materials for mesenchymal stem cells. The pore space and mechanical characteristics of materials obtained with amorphous nanodispersed calcium hydroxyapatite were similar to the properties of natural bone. Moreover, these materials surpassed titanium—cobalt allows in biocompatibility. Our results indicate that the introduction of amorphous nanodispersed calcium hydroxyapatite into the reaction mixture during self-propagating high-temperature synthesis has a modifying effect on the pore space of composite materials and increases their biocompatibility and adhesiveness for cells. We conclude that these materials may be used as a carrier of stem cells and progenitor cells in hybrid implants. Translated from Kletochnye Tekhnologii v Biologii i Meditsine, No. 1, pp. 52–58, 2009     

In vitro biocompatibility and degradation of terpolyester 3HB-co-4HB-co-3HHx,consisting of 3-hydroxybutyrate, 4-hydroxybutyrate and 3-hydroxyhexanoate

A terpolyester consisting of 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB) and 3-hydroxyhexanoate (3HHx), abbreviated as P(3HB-co-4HB-co-3HHx), was studied for possible application as an implant biomaterial. L929 mouse fibroblasts, MC3T3-E1 murine osteoblasts and a human cell line of immortalized human keratinocyte (HaCat cells) were used to study the biocompatibility of P(3HB-co-4HB-co-3HHx). Cell morphology and cell activity were studied using scanning electron microscopy (SEM) and the MTT assay, respectively. All three cell types showed higher activities when grown on films of P(3HB-co-4HB-co-3HHx) compared with their growth on poly(lactic acid) (PLA), co-polyester PHBHHx films and on polylysine-coated plates (blank), respectively. The three cell types grown on the terpolyester also demonstrated a well-spread cell shape and large number of pseudopods due to strong cell–cell and cell–material interactions. It was clearly observed that P(3HB-co-4HB-co-3HHx) had a much faster degradation rate than PHBHHx after 15 weeks of incubation in phosphate-buffered saline under dynamic conditions. The results proved that the terpolyester had favorable biocompatibility and biodegradability compared with the well-studied polyesters PLA and PHBHHx.     

The simultaneous effect of polymer chemistry and device geometry on the in vitro activation of murine dendritic cells

Polyanhydrides are a promising class of biomaterials for use as vaccine adjuvants and as multi-component implants. Their properties can be tailored for such applications as controlled drug release, drug stability, and/or immune regulation (adjuvant effect). Understanding the induction of immunomodulatory mechanisms of this polymer system is important for the design and development of efficacious vaccines and tissue compatible multi-component implantable devices using this polymer system. This study describes the development of a rapid multiplexed method for the investigation of the adjuvanticity of polyanhydride nanospheres and films using murine dendritic cells (DCs). To assess the immune response, cell surface markers including MHC II, CD86, CD40, and CD209 and cytokines including IL-6, IL-12p40, and IL-10 were measured. The DCs incubated with nanospheres displayed enhanced expression of all the surface markers and the production of IL-12p40 compared to DCs incubated with polymer films in a chemistry-dependent manner. This suggests that polyanhydrides of various chemistries and device geometries can be tailored to achieve desired levels of immune cell activation for specific applications. The observed biocompatibility and activation of DCs by polyanhydride devices supports their inclusion in vaccine delivery devices as well as in multi-component medical implants.     

Concurrent improvement in biocompatibility and bioinertness of diamond-like carbon films with nitrogen doping

The surfaces of implantable biomaterials improving biocompatibility and bioinertness are critical for new application of bioimplantable devices. Diamond-like carbon (DLC) film is a promising biomaterial with use for coating bioimplantable devices because of its good biocompatibility, bioinertness, and mechanical properties. In this study, concurrent improvement in biocompatibility and bioinertness of DLC films has been achieved using N-incorporation technique. The N doping degree was found to play an important role in affecting the biocompatibility and bioinertness of N-doped DLC films. The results indicated that the N-doped DLC films deposited at N(2) concentration of 5% could help to create suitable condition of surface/structure/adhesion combination of DLC films in the both affinity of the L929 mouse fibroblasts and electrochemical inertness in the Hank's balanced salt solutions (simulating human body fluids). N doping supports the attachment and proliferation of cells and prevents the permeation of electrolyte solutions, thereby simultaneity improved the biocompatibility and bioinertness of DLC films. This finding is useful for the fabrication and encapsulation of in vivo devices without induced immune response in the human body. ? 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3151-3156, 2012.     

Designing of a Si-MEMS device with an integrated skeletal muscle cell-based bio-actuator

With the aim of designing a mechanical drug delivery system involving a bio-actuator, we fabricated a Micro Electro Mechanical Systems (MEMS) device that can be driven through contraction of skeletal muscle cells. The device is composed of a Si-MEMS with springs and ratchets, UV-crosslinked collagen film for cell attachment, and C2C12 muscle cells. The Si-MEMS device is 600 μm × 1000 μm in size and the width of the collagen film is 250 ~ 350 μm, which may allow the device to go through small blood vessels. To position the collagen film on the MEMS device, a thermo-sensitive polymer was used as the sacrifice-layer which was selectively removed with O₂ plasma at the positions where the collagen film was glued. The C2C12 myoblasts were seeded on the collagen film, where they proliferated and formed myotubes after induction of differentiation. When C2C12 myotubes were stimulated with electric pulses, contraction of the collagen film-C2C12 myotube complex was observed. When the edge of the Si-MEMS device was observed, displacement of ~8 μm was observed, demonstrating the possibility of locomotive movement when the device is placed on a track of adequate width. Here, we propose that the C2C12-collagen film complex is a new generation actuator for MEMS devices that utilize glucose as fuel, which will be useful in environments in which glucose is abundant such as inside a blood vessel.     

Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo

In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 ?broblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting.     

Effect of composition of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) on growth of fibroblast and osteoblast

Films made of poly (3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) (PHBHHx) consisting of 5%, 12% and 20% hydroxyhexanoate (HHx), respectively, were evaluated for biomedical application in comparison with poly (L-Lactide) (PLA). With the increase of HHx content in PHBHHx, the polymer surface properties changed accordingly. P(HB-co-20%-HHx) had the smoothest surface while PHB surface was most hydrophilic among the evaluated PHB and all the PHBHHx. All PHBHHx also showed strong protein affinity and biocompatibility. It was found that fibroblast and osteoblast had different responses to these polymers: fibroblast cells favored P(HB-co-20%-HHx), yet osteoblast cells preferred P(HB-co-12%-HHx). PHB and all PHBHHx appeared to have better biocompatibility for fibroblast and osteoblast compared with PLA. Polymers possessing different surface properties may help meet different cellular requirements. Combined with their good mechanical properties for elongation and adjustable biocompatibility, PHBHHx may meet the needs of growth requirements of different tissues and cells.     

Plasma deposition for biomedical applications: a brief review.

Radio frequency plasma-deposited thin films offer an advantageous mechanism to alter the surface properties of biomaterials and medical devices without affecting the mechanical properties or primary fabrication. Such coatings are tightly adherent, conformal, and easily applied. They also exhibit excellent biocompatibility qualities. Examples are presented of four different thin film plasma treatments that show promise for reducing the platelet reactivity of materials, enhancing their ability to grow cells, preventing protein pickup by surfaces, and improving the biocompatibility of ophthalmic devices.     

多孔状聚乳酸—聚乙醇酸材料基础与应用研究

有机高分子聚合物聚乳酸、聚乙醇酸具有良好的生物相容性和可降解性 ,已被广泛应用于临床。随着材料学的发展 ,该类材料又被制成多孔状 ,成为较为理想的细胞种植基质和生长因子载体 ,为骨和软骨缺损的修复和组织工程学的发展开创了崭新的局面。本文就多孔状聚乳酸、聚乙醇酸的制作技术、性能的特殊性和应用状况作一综述。     

Thyrotropin-releasing hormone inhibits long-term potentiation in synaptic systems of rat hippocampus

The effects of thyrotropin-releasing hormone (TRH) on long-term potentiation of field responses in mossy fibers—CA3 and Shaffer collaterals—CA1 synaptic systems were studied on rat hippocampal slices. Incubation with micromolar concentrations of TRH inhibited the development of long-term potentiation in both synaptic systems. It is suggested that this phenomenon underlies the antiamnesic effect of TRH. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 12, pp. 690–693, December, 1999     

Growth of various cell types in the presence of lactic and glycolic acids: the adverse effect of glycolic acid released from PLAGA copolymer on keratinocyte proliferation

Poly(α-hydroxy-acid)s derived from lactic acid (LA) and glycolic acid (GA) are bioresorbable polymers that are currently used in human surgery and in pharmacology to make temporary therapeutic devices. Nowadays, increasing attention is paid to these polymers in the field of tissue engineering. However, the literature shows that a large number of factors can affect many of their properties and the responses of biological systems. As part of our investigation of the biocompatibility of degradable aliphatic polyesters, the effects of LA and GA on the proliferation of various cells under in vitro cell culture conditions were studied. The release of LA and GA from films made of a copolymer synthesized by the zinc lactate method and composed of 37.5% L-lactyl, 37.5% D-lactyl, and 25% glycolyl repeating units was first investigated over a period of 30 days under abiotic conditions in a cell culture medium in order to identify a range of acid concentrations consistent with releases to be expected in real cell cultures. Four cell lines, namely 3T3-J2, C3H10^1/2, A431, and HaCat, and three primary cell cultures, namely rat endothelial cells, rat smooth muscle cells, and human dermal fibroblasts, were then allowed to grow in the presence of LA and GA at various concentrations taken within the selected 10–1000 mg/cm³ range. Little or no effect was observed on the proliferation of all cells except human keratinocytes, whose growth was dramatically inhibited by GA at concentrations as low as 10 mg/cm³. The inhibiting effect of GA was confirmed by considering the growth of keratinocytes on films made of the same copolymer, in comparison with poly(DL-lactic acid) and polystyrene taken as references. This work shows that GA-releasing degradable matrices are not adapted to the culture of keratinocytes with the aim of making skin grafts.     

Differences in quadriceps muscle strength and fatigue between lean and obese subjects

The present study aimed to compare quadriceps femoris muscle strength and fatigue between obese (grade II and III) and nonobese adults. Ten obese (mean age: 25 years; mean BMI: 41 kg/m2) and ten lean (mean age: 27 years; mean BMI: 23 kg/m2) men were tested. Quadriceps muscle fatigue was quantified as the (percent) torque loss during a voluntary isokinetic (50 maximal contractions at 180°/s) and an electrostimulated (40 Hz) isometric protocol (5 min, 10% of the maximal torque). Maximal voluntary isometric and isokinetic torque and power were also measured. Voluntary torque loss was significantly higher (P < 0.05) in obese (−63.5%) than in lean subjects (−50.6%). Stimulated torque decreased significantly (P < 0.05) but equally in the two subject groups. Obese subjects displayed higher absolute (+20%; P < 0.01) but lower relative (i.e., normalized to body mass) (−32%; P < 0.001) muscle torque and power than their lean counterparts. Obese individuals demonstrated lower fatigue resistance during voluntary but not during stimulated knee extensions compared to their nonobese counterparts. Peripheral mechanisms of muscle fatigue—at least those associated to the present stimulated test—were not influenced by obesity. The observed quadriceps muscle function impairments (voluntary fatigue and relative strength) probably contribute to the reduced functional capacity of obese subjects during daily living activities.     

Effect of Antibodies to Glutamate and GABA on the Stress Response in C57Bl/6 Mice

We studied the effect of antibodies to glutamate and GABA (active immunization with conjugates of glutamate—bovine serum albumin and GABA—bovine serum albumin) on the course of combined water-immersion stress in C57Bl/6 mice. Preimmunization of animals with the conjugate of glutamate—bovine serum albumin was accompanied by strong production of antibodies to glutamate, which reduced the majority of signs of the stress response. Antibodies to GABA had no effect on the development of stress. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 3, pp. 272–275, March, 2009     

Structural Characteristics and Properties of Silk Fibroin/Poly(lactic acid) Blend Films

This paper describes the preparation and characterization of blend films composed of regenerated silk fibroin (SF) and poly(lactic acid) (PLA). FT-IR and XRD of the SF/PLA blend films with different ratios indicated that the secondary structural transition of SF from Silk I to Silk II was induced upon blending with PLA. The effects of SF/PLA blend ratios on the mechanical and physical properties of the blend films were investigated. Compared to pure SF film, the mechanical and thermal properties of the blend films were improved, and surface hydrophilicity and swelling capacity decreased due to the secondary structural transition of SF to Silk II. Among the blend films with different ratios, the SF/PLA blend film with 7 wt% PLA content showed excellent mechanical properties. Meanwhile, the BSA adsorption amount on the blend film increased with the increase of PLA content. In vitro cell adhesion test showed that the blend film was a good matrix for the growth of L929 mouse fibroblast cells. Consequently, controlling the PLA content in the SF film can improve the mechanical and physical properties of the SF film and provide a promising opportunity to widen potential application of SF in the biomaterials field.     

Effects of chronic hypoxia and endurance training on muscle capillarity in rats

Skeletal muscle capillarity expressed as capillary density (CD), and number of capillaries per fibre (C/F), as well as the mean fibre cross-sectional area (FCSA), were determined in the extensor digitorum longus (EDL), plantaris (PLA) and soleus (SOL) muscles of four groups of eight rodents trained on a swimming exercise programme (T) or maintained sedentary (S), at sea level (SL) or at simulated altitude (HA), barometric pressure 61.7 kPa (463 torr) for 12 weeks. It was shown that both HA exposure and endurance training decreased body and skeletal muscles weights (P<0.001). However, neither HA exposure nor endurance training induce any variation in relative importance in the skeletal muscle mass. Altitude exposure and endurance training had increasing effects on CD in all muscles studied (P<0.001). This study confirms the fact that altitude exposure has no direct effect on capillary development. On the other hand, the capillary supply of the several slow- and fast- twitch skeletal muscles studied is increased by endurance training. This real enhancement in capillary network is ascertained by an increase in the C/F ratio (+7%, +26%, +16%, in PLA, EDL, and SOL muscles, respectively at sea level, and +19.5%, +30%, and +14% respectively at HA). These results indicate that the effects of chronic exercise on skeletal muscle capillarity estimated by the C/F ratio, are greater in an hypobaric environment than in a SL environment.     

Pathological changes in cardiospasm

Anatomicopathological changes of the esophagus and stomach at different stages of cardiospasm are shown. As the disease develops, macroscopic changes of the esophagus, manifesting themselves in its enlargement, and microscopic changes — perivascular lymphocyte and plasmacyte infiltration and muscle fiber hypertrophy and edema — are noted. During the development of cardiospasm inflammatory-degenerative changes progress in all esophageal layers. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 216–218, August, 1994 Presented by T. T. Berezov, Member of the Russian Academy of Medical Sciences     

In vivo evaluation of an ultra-thin polycaprolactone film as a wound dressing

The use of ultra-thin films as dressings for cutaneous wounds could prove advantageous in terms of better conformity to wound topography and improved vapour transmission. For this purpose, ultra-thin poly(epsilon-caprolactone) (PCL) films of 5-15 microm thickness were fabricated via a biaxial stretching technique. To evaluate their in vivo biocompatibility and feasibility as an external wound dressing, PCL films were applied over full and partial-thickness wounds in rat and pig models. Different groups of PCL films were used: untreated, NaOH-treated, untreated with fibrin, NaOH-treated with perforations, and NaOH-treated with fibrin and S-nitrosoglutathione. Wounds with no external dressings were used as controls. Wound contraction rate, histology and biomechanical analyses were carried out. Wounds re-epithelialized completely at a comparable rate. Formation of a neo-dermal layer and re-epithelialization were observed in all the wounds. A lower level of fibrosis was observed when PCL films were used, compared to the control wounds. Ultimate tensile strength of the regenerated tissue in rats reached 50-60% of that in native rat skin. Results indicated that biaxially-stretched PCL films did not induce inflammatory reactions when used in vivo as a wound dressing and supported the normal wound healing process in full and partial-thickness wounds.     

<Emphasis Type="Italic">In Vitro</Emphasis> Accumulation of Complexes of Endotoxin and Low-Density Lipoproteins by Macrophages and Arterial Wall

Binding and uptake of complexes of endotoxin and low-density lipoproteins (LPS—LDL) in the arterial wall and mononuclear phagocytes were studied under in vitro conditions. Incubation of aortic explants from Wistar rats with complexes of ¹²⁵I—LDL and S. minnesota R595 LPS or ¹²⁵I--LDL was accompanied by a 6-fold increase in binding (0°C) and 2-fold increase in the uptake (37°C) of LDL—LPS complexes as compared to free LDL. Binding and degradation of ¹²⁵I—LDL—LPS complexes in the culture of peritoneal macrophages were higher compared to the corresponding parameters for free ¹²⁵I—LDL. Our results suggest that the formation of LDL—LPS complexes is followed by the increased binding and accumulation of LDL in the arterial wall and macrophages. These changes probably induce the cascade of major atherogenic events in the vascular wall. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 2, pp. 148–151, February, 2009